CN114828327A - Color temperature adjustable light emitting device, color temperature adjusting circuit/chip and LED equipment - Google Patents
Color temperature adjustable light emitting device, color temperature adjusting circuit/chip and LED equipment Download PDFInfo
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- H05B45/20—Controlling the colour of the light
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Abstract
The invention provides a color temperature adjustable light-emitting device, a color temperature adjusting circuit/chip and LED equipment, wherein the color temperature adjustable light-emitting device comprises: a first light emitting assembly; the second light-emitting component is connected with the first light-emitting component in parallel; the color temperature adjusting module is connected with the first light emitting assembly and the second light emitting assembly in series and adjusts currents respectively flowing through the first light emitting assembly and the second light emitting assembly by setting resistance values of resistors of the color temperature adjusting module; and the control module is connected with the color temperature adjusting module and outputs a pulse width adjustable control signal to control the equivalent output resistor of the color temperature adjusting module so as to realize adjustable mixed color temperature of the first light-emitting component and the second light-emitting component. The invention can finely adjust the resistance value of the related resistor in the color temperature adjusting module, can realize the fine adjustment of the color temperature under the condition of not moving the control module, and can ensure the consistency of the output target color temperature among the individual light-emitting devices even when the LED elements of different bins are adopted.
Description
Technical Field
The invention belongs to the technical field of illumination, relates to a light-emitting device, and particularly relates to a color temperature adjustable light-emitting device, a color temperature adjusting circuit/chip and LED equipment.
Background
The human eye has a very high resolution for the color and brightness of light and is particularly sensitive to differences and variations in color. In the early days, since LEDs were used primarily as indicator or display lights and were generally present as a single device, the requirements for sorting of their wavelengths and control of their brightness were not high. However, as the efficiency and brightness of LEDs are continuously improved, the application range of the LEDs is wider and wider. When LEDs are used as array display and screen elements, non-uniformity occurs with unsorted LEDs due to the sensitivity of the human eye to the wavelength and brightness of the color, thereby affecting the visual effect of people. Either the wavelength or the brightness is not uniform, giving an uncomfortable feeling. Sorting of LEDs is impossible to do for all parameters such as optical, electrical properties and lifetime and reliability, but sorting is done according to several key parameters generally of interest, including dominant wavelength, luminous intensity, luminous flux, color temperature, operating voltage, reverse breakdown voltage, etc.
One existing sorting method is to sort in the form of LED tubes, and a test sorter will automatically separate LEDs into different bins according to settings. Since the demand for LEDs has become increasingly stringent, the early sorters were 32Bin later increased to 64Bin, and there are now 72Bin commercial sorters. Even so, the number of sub-bins still cannot meet the demands of production and market, and still in the field of lighting. The production of the same lamp cannot ensure that the purchased LEDs are all the same Bin, so that the brightness or color temperature of the same lamp has macroscopic difference, and the quality of the product and the trust of customers are seriously influenced.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, it is an object of the present invention to provide a color temperature tunable light emitting device, a color temperature tuning circuit/chip and an LED apparatus, which are used to solve the problem of the existing light emitting component that the output color temperature is different from the target color temperature when LEDs of different bins are used.
To achieve the above and other related objects, the present invention provides a color temperature tunable light emitting device, including: a first light emitting assembly; the second light-emitting component is connected with the first light-emitting component in parallel; the color temperature adjusting module is connected with the first light-emitting assembly and the second light-emitting assembly in series and used for adjusting currents flowing through the first light-emitting assembly and the second light-emitting assembly respectively; and the control module is connected with the color temperature adjusting module and outputs a pulse width adjustable control signal to control the equivalent output resistor of the color temperature adjusting module so as to realize adjustable mixed color temperature of the first light-emitting component and the second light-emitting component.
In an embodiment of the present invention, the color temperature adjusting module includes 2 variable resistance modules; the other variable resistance module is connected with the second light-emitting component in series; and the adjustable end of the variable resistance module is connected with the output end of the control module.
In an embodiment of the present invention, the control module has 2 output terminals for respectively outputting 1-way pulse width adjustable control signal; 2 output ends of the control module are connected with the adjustable ends of the 2 variable resistance modules in a one-to-one correspondence manner.
In an embodiment of the invention, the color temperature adjustment module includes a first control terminal, a second control terminal, a first positive terminal, a second positive terminal, and a negative terminal; the first control end is an adjustable end of the variable resistance module, and the first positive end is a positive end of the adjustable resistance module; the second control end is an adjustable end of the other variable resistance module, and the second positive end is a positive end of the other adjustable resistance module; the negative ends are the negative ends of the 2 variable resistance modules; the first control end is connected with one output end of the control module, and the second control end is connected with the other output end of the control module; the first positive terminal is connected with the negative electrode of the first light-emitting component, and the second positive terminal is connected with the negative electrode of the second light-emitting component; the negative electrode end is used for being connected with a negative electrode of a power supply; the positive electrode of the first light-emitting assembly is connected with the positive electrode of the power supply, and the positive electrode of the second light-emitting assembly is connected with the positive electrode of the power supply.
In an embodiment of the present invention, the color temperature adjusting module further includes a voltage dividing module; the voltage division module is connected with the variable resistance module in parallel, and the output end of the voltage division module is connected with the adjustable end of the other variable resistance module; and the adjustable end of the variable resistance module is connected with the output end of the control module.
In an embodiment of the invention, the color temperature adjustment module includes a first control terminal, a first positive terminal, a second positive terminal, and a negative terminal; the first control end is an adjustable end of the variable resistance module, and the first positive end is a positive end of the adjustable resistance module; the negative ends are the negative ends of the 2 variable resistance modules; the first control end is connected with the output end of the control module; the first positive terminal is connected with the negative electrode of the first light-emitting component, and the second positive terminal is connected with the negative electrode of the second light-emitting component; the negative electrode end is used for being connected with a negative electrode of a power supply; the positive electrode of the first light-emitting assembly is connected with the positive electrode of the power supply, and the positive electrode of the second light-emitting assembly is connected with the positive electrode of the power supply.
In an embodiment of the present invention, the variable resistance module includes a MOS transistor, a first resistor, a second resistor, a positive terminal, a negative terminal, and an adjustable terminal; the grid electrode of the MOS tube is connected with the adjustable end, the source electrode of the MOS tube is connected with one end of the second resistor, and the drain electrode of the MOS tube is connected with the positive end; one end of the first resistor is connected with the drain electrode of the MOS tube, and the other end of the first resistor is connected with the cathode end; the other end of the second resistor is connected with the negative electrode end; the adjustable end is connected with the output end of the control module.
In an embodiment of the invention, the first light emitting device includes a set of LED circuits; the second light emitting assembly comprises a set of LED circuits; the first light-emitting component and the second light-emitting component have different color temperatures.
In an embodiment of the present invention, the control module outputs a pulse width adjustable control signal with a duty ratio δ to control an equivalent output resistance of a variable resistance module in the color temperature adjusting module to be VR:
when the constant current source supplies power to the variable resistance module, the current flowing through the variable resistance module is constant and is I; when the variable resistance module receives the high level of the pulse width adjustable control signal, the variable powerThe MOS tube in the resistance module is conducted, the equivalent resistance between the positive terminal and the negative terminal of the variable resistance module is that the first resistance RA and the second resistance RB are connected in parallel, namely the resistance value of the equivalent resistance is
At this time, the voltage between the positive electrode end and the negative electrode end of the variable resistance module is U '═ I · R'; when the variable resistance module receives the low level of the pulse width adjustable control signal, the MOS tube in the variable resistance module is turned off, only the first resistor RA is connected between the positive terminal and the negative terminal of the variable resistance module, and the voltage between the positive terminal and the negative terminal of the variable resistance module is U ═ I · RA at the moment; the average voltage between the positive terminal and the negative terminal of the variable resistance module in the whole PWM period is as follows:
in the whole PWM period, the average resistance value between the positive terminal and the negative terminal of the variable resistance module is the equivalent output resistance VR of the variable resistance module.
In an embodiment of the present invention, the control module outputs a pulse width adjustable control signal with a duty ratio δ to control an equivalent output resistance of a variable resistance module in the color temperature adjusting module to be VR:
when the constant voltage source supplies power to the variable resistance module, the voltage between the positive terminal and the negative terminal of the variable resistance module is constant and is U; when the variable resistance module receives the high level of the pulse width adjustable control signal, the current flowing into the positive end and the negative end of the variable resistance module is
When the variable resistance module receives the low level of the pulse width adjustable control signal, the current flowing into the positive end and the negative end of the variable resistance module is
The average value of the current flowing into the positive terminal and the negative terminal of the variable resistance module in the whole PWM period is as follows:
in the whole PWM period, the average resistance value between the positive terminal and the negative terminal of the variable resistance module is the equivalent output resistance VR of the variable resistance module.
In an embodiment of the present invention, the control module outputs a pulse width adjustable control signal with a duty cycle δ 1 to control an equivalent output resistance of one variable resistance module in the color temperature adjusting module to be VR1, and outputs a pulse width adjustable control signal with a duty cycle δ 2 to control an equivalent output resistance of another variable resistance module in the color temperature adjusting module to be VR2, so that the equivalent output resistance of the color temperature adjusting module is VR; when the current is controlled by a constant current source I total When the color temperature adjustable light-emitting device is powered, the voltage drop of the first light-emitting component is V LED1 The average current flowing through the first light-emitting component is I1; the voltage drop of the second light-emitting component is V LED2 The average current flowing through the second light-emitting component is I2; according to the relational expression
Therefore, the control module changes the duty ratio of any one of the two pulse width adjustable control signals, i.e., changes VR2/VR1, and further changes the current ratios respectively flowing through the first light-emitting assembly and the second light-emitting assembly, so that the light-emitting ratios of the first light-emitting assembly and the second light-emitting assembly are changed, and the mixed color temperature of the first light-emitting assembly and the second light-emitting assembly is changed.
The present invention also provides a color temperature adjusting chip for controlling a mixed color temperature of at least 2 sets of light emitting components, the color temperature adjusting chip comprising: the color temperature adjusting module is respectively connected with the at least two groups of light-emitting components in series and is used for adjusting the current flowing through each light-emitting component; and the control module is connected with the color temperature adjusting module and outputs a pulse width adjustable control signal to control the equivalent output resistor of the color temperature adjusting module so as to realize that the mixed color temperature of at least 2 groups of light-emitting components is adjustable.
In an embodiment of the present invention, the color temperature adjusting module includes at least 2 variable resistance modules; each variable resistance module is connected with each light-emitting component in series in a one-to-one correspondence manner; and the adjustable end of the variable resistance module is connected with the output end of the control module.
In an embodiment of the invention, the color temperature adjusting chip further includes: and the communication module is in communication connection with the control module and is used for receiving a duty ratio setting instruction of the pulse width adjustable control signal.
The invention also provides a color temperature adjusting chip which comprises the color temperature adjusting circuit.
The invention also provides LED equipment which comprises the color temperature adjustable light-emitting device.
The invention also provides LED equipment which comprises the color temperature adjusting circuit.
The invention also provides LED equipment which comprises the color temperature adjusting chip.
As described above, the color temperature adjustable light emitting device, the color temperature adjusting circuit/chip and the LED apparatus according to the present invention have the following advantages:
the invention can finely adjust the resistance value of the related resistor in the color temperature adjusting module, can realize the fine adjustment of the color temperature under the condition of not moving the control module, can ensure the consistency of the output target color temperature among the individual light-emitting devices even when adopting LED elements of different bins, not only has attractive appearance and high quality, but also is convenient for the management of production and supply chains.
Drawings
Fig. 1 is a schematic structural diagram illustrating an implementation of a color temperature adjustable light emitting device according to an embodiment of the invention.
Fig. 2 is a schematic diagram illustrating an implementation structure of a color temperature adjusting module of a color temperature adjustable light emitting device according to an embodiment of the invention.
Fig. 3A is a schematic diagram illustrating an implementation structure of a control module of a color temperature adjustable light emitting device according to an embodiment of the invention.
Fig. 3B is a schematic view illustrating a port structure of a color temperature adjusting module of the color temperature adjustable light emitting device according to an embodiment of the invention.
Fig. 3C and fig. 3D are schematic circuit diagrams illustrating an exemplary circuit structure of a color temperature adjusting module of a color temperature adjustable light emitting device according to an embodiment of the invention.
Fig. 4A is a schematic diagram illustrating another implementation structure of the control module of the color temperature adjustable light emitting device according to the embodiment of the invention.
Fig. 4B is a schematic view illustrating another port structure of the color temperature adjusting module of the color temperature adjustable light emitting device according to the embodiment of the invention.
Fig. 4C is a schematic circuit diagram illustrating another exemplary circuit structure of the color temperature adjusting module of the color temperature adjustable light emitting device according to the embodiment of the invention.
Fig. 4D is a schematic circuit diagram illustrating a third exemplary circuit structure of a color temperature adjusting module of a color temperature adjustable light emitting device according to an embodiment of the invention.
Fig. 5A is a schematic diagram illustrating an implementation structure of a color temperature adjustment circuit according to an embodiment of the invention.
Fig. 5B is a schematic diagram illustrating an implementation structure of a color temperature adjustment module of a color temperature adjustment circuit according to an embodiment of the invention.
Fig. 5C is a schematic diagram illustrating another implementation structure of the color temperature adjustment circuit according to the embodiment of the invention.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.
Referring to fig. 1, the present invention provides a color temperature adjustable light emitting device 100, which includes: the first light emitting device 110, the second light emitting device 120, the color temperature adjusting module 130, and the control module 140.
The first light-emitting component is used for emitting light and comprises a group of LEDs; the group of LEDs can be formed by connecting any number of LEDs in series, parallel, series-parallel or the like.
The second light-emitting assembly is connected with the first light-emitting assembly in parallel. The second group of light emitting elements is generally the same structure as the first group of light emitting elements. The second light-emitting component is used for emitting light and comprises a group of LEDs; the group of LEDs can be formed by connecting any number of LEDs in series, parallel, series-parallel or the like. The color temperature of the first light-emitting component and the color temperature of the second light-emitting component are deviated due to different bins of the LEDs.
The color temperature adjusting module is connected with the first light emitting assembly and the second light emitting assembly in series, and adjusts currents respectively flowing through the first light emitting assembly and the second light emitting assembly by setting resistance values of resistors of the color temperature adjusting module. The invention can finely adjust the resistance value of the related resistor in the color temperature adjusting module, can finely adjust the color temperature under the condition of not moving the control module, and can ensure the consistency of the output target color temperature of the lamp when adopting the LED elements of different bins.
The control module is connected with the color temperature adjusting module and outputs a pulse width adjustable control signal to control the equivalent output resistor of the color temperature adjusting module so as to realize adjustable mixed color temperature of the first light-emitting component and the second light-emitting component. The invention adopts PWM signal to control the equivalent impedance of the variable resistance module to change, so as to change the current of the LED groups with different color temperatures, thus achieving the purpose of color temperature adjustment.
Referring to fig. 2, in an embodiment of the present invention, the color temperature adjustment module includes 2 variable resistance modules 131; the other variable resistance module is connected with the second light-emitting component in series; and the adjustable end of the variable resistance module is connected with the output end of the control module.
The invention can finely adjust the resistance value of the related resistor in the variable resistor module, can finely adjust the color temperature under the condition of not moving the control module, can ensure the consistency of the output target color temperature of the lamp when adopting the LED elements of different bins, is beautiful and high in quality, and is convenient for the management of production and supply chains.
Referring to fig. 3A, in an embodiment of the present invention, the control module has 2 output terminals for respectively outputting 1-way pulse width adjustable control signal; 2 output ends of the control module are connected with the adjustable ends of the 2 variable resistance modules in a one-to-one correspondence manner.
Referring to fig. 3B, in an embodiment of the invention, the color temperature adjustment module includes a first control terminal, a second control terminal, a first positive terminal, a second positive terminal, and a negative terminal; the first control end is an adjustable end of the variable resistance module, and the first positive end is a positive end of the adjustable resistance module; the second control end is an adjustable end of the other variable resistance module, and the second positive end is a positive end of the other adjustable resistance module; the negative ends are the negative ends of the 2 variable resistance modules; the first control end is connected with one output end of the control module, and the second control end is connected with the other output end of the control module; the first positive terminal is connected with the negative electrode of the first light-emitting component, and the second positive terminal is connected with the negative electrode of the second light-emitting component; the negative electrode end is used for being connected with a negative electrode of a power supply; the positive electrode of the first light-emitting assembly is connected with the positive electrode of the power supply, and the positive electrode of the second light-emitting assembly is connected with the positive electrode of the power supply.
Referring to fig. 3C and 3D, in an embodiment of the invention, the variable resistor module 131 includes a MOS transistor, a first resistor, a second resistor, a positive terminal, a negative terminal, and an adjustable terminal; the grid electrode of the MOS tube is connected with the adjustable end, the source electrode of the MOS tube is connected with one end of the second resistor, and the drain electrode of the MOS tube is connected with the positive end; one end of the first resistor is connected with the drain electrode of the MOS tube, and the other end of the first resistor is connected with the cathode end; the other end of the second resistor is connected with the negative electrode end; the adjustable end is connected with the output end of the control module.
The operation principle of fig. 3A to 3C is explained as follows:
scene 1: when the constant current source supplies power to the variable resistance module, the current flowing through the variable resistance module is constant and is I; the control module outputs a pulse width adjustable control signal with a duty ratio delta to control the equivalent output resistance of a variable resistance module in the color temperature adjusting module to be VR:
when the variable resistance module receives the high level of the pulse width adjustable control signal, the MOS transistor in the variable resistance module is turned on, and the equivalent resistance between the positive terminal and the negative terminal of the variable resistance module is that the first resistor RA and the second resistor RB are connected in parallel, that is, the resistance of the equivalent resistance is
At this time, the voltage between the positive electrode end and the negative electrode end of the variable resistance module is U '═ I · R';
when the variable resistance module receives the low level of the pulse width adjustable control signal, the MOS tube in the variable resistance module is turned off, only the first resistor RA is connected between the positive terminal and the negative terminal of the variable resistance module, and the voltage between the positive terminal and the negative terminal of the variable resistance module is U ═ I · RA at the moment;
the average voltage between the positive terminal and the negative terminal of the variable resistance module in the whole PWM period is as follows:
in the whole PWM period, the average resistance between the positive terminal and the negative terminal of the variable resistance module is the equivalent output resistance VR of the variable resistance module:
scene 2: when the constant voltage source supplies power to the variable resistance module, the voltage between the positive terminal and the negative terminal of the variable resistance module is constant and is U; the control module outputs a pulse width adjustable control signal with a duty ratio delta to control the equivalent output resistance of a variable resistance module in the color temperature adjusting module to be VR:
when the variable resistance module receives the high level of the pulse width adjustable control signal, the current flowing into the positive end and the negative end of the variable resistance module is
When the variable resistance module receives the low level of the pulse width adjustable control signal, the current flowing into the positive end and the negative end of the variable resistance module is
The average value of the current flowing into the positive terminal and the negative terminal of the variable resistance module in the whole PWM period is as follows:
in the whole PWM period, the average resistance between the positive terminal and the negative terminal of the variable resistance module is the equivalent output resistance VR of the variable resistance module:
in summary, no matter the constant voltage source or the constant current source supplies power to the variable resistance module, the equivalent resistance, i.e., the average resistance, between the terminal 1 and the terminal 2 is related to the duty ratio δ of the pulse width adjustable control signal (PWM), and changing the duty ratio δ can change the resistance value of the average resistance (or called equivalent resistance) between the positive terminal (terminal 1) and the negative terminal (terminal 2) of the variable resistance module, so as to change the current flowing through the first light emitting component or/and the second light emitting component, thereby realizing the adjustment of the mixed color temperature of the light emitting device.
Referring to fig. 4A, in an embodiment of the invention, the color temperature adjustment module 130 includes 2 variable resistance modules 131 and a voltage division module 132; the other variable resistance module is connected with the second light-emitting component in series; the voltage division module is connected with the variable resistance module in parallel, and the output end of the voltage division module is connected with the adjustable end of the other variable resistance module; and the adjustable end of the variable resistance module is connected with the output end of the control module.
The single-path PWM signal control scheme adopted by the invention simplifies the control mode, makes the design of the control module easier to realize and has lower control error probability.
Referring to fig. 4B, in an embodiment of the invention, the color temperature adjustment module includes a first control terminal, a first positive terminal, a second positive terminal, and a negative terminal; the first control end is an adjustable end of the variable resistance module, and the first positive end is a positive end of the adjustable resistance module; the negative ends are the negative ends of the 2 variable resistance modules; the first control end is connected with the output end of the control module; the first positive terminal is connected with the negative electrode of the first light-emitting component, and the second positive terminal is connected with the negative electrode of the second light-emitting component; the negative electrode end is used for being connected with a negative electrode of a power supply; the positive electrode of the first light-emitting assembly is connected with the positive electrode of the power supply, and the positive electrode of the second light-emitting assembly is connected with the positive electrode of the power supply.
Referring to fig. 4C, in an embodiment of the invention, the variable resistance module 131 includes a MOS transistor (Q1, Q2), a first resistor (R1A, R2A), a second resistor (R1B, R2B), a positive terminal, a negative terminal, and an adjustable terminal; the grid electrode of the MOS tube is connected with the adjustable end, the source electrode of the MOS tube is connected with one end of the second resistor, and the drain electrode of the MOS tube is connected with the positive end; one end of the first resistor is connected with the drain electrode of the MOS tube, and the other end of the first resistor is connected with the cathode end; the other end of the second resistor is connected with the negative electrode end; the adjustable end is connected with the output end of the control module. The voltage division module comprises a third resistor and a fourth resistor which are connected in series; one end of the third resistor is connected with the source electrode of the MOS tube, and the other end of the third resistor is connected with the adjustable end of the other variable resistor module; one end of the fourth resistor is connected with the other end of the third resistor, and the other end of the fourth resistor is connected with the negative electrode end. The voltage divider module 132 includes a resistor R3 and a resistor R4.
Fig. 4D is a modified structure of the circuit structure shown in fig. 4C, which has the same function as fig. 4C and can be used as an alternative to fig. 4C. The voltage divider module 132 includes a resistor R3, a resistor R4, and a zener diode D.
The operation principle of fig. 4A to 4C is explained as follows:
the duty ratio of the PWM signal sent by the control module to one variable resistor module VR1 is δ 1, the duty ratio of the PWM signal sent by the control module to another variable resistor module VR2 is δ 2, the equivalent resistance value of the variable resistor module VR1 is VR1, and the equivalent resistance value of the variable resistor module VR2 is VR 2.
The current of the DC Power supply DC Power in scene 1 is I total 。
When the LED is usedWhen the LED is conducted, the voltage at the two ends of the LED can be regarded as constant conduction voltage drop and is not influenced by the magnitude of the flowing current, and the voltage drop of the 1 st LED group (namely the first light-emitting component) is recorded as V LED1 The average current flowing is I1; the voltage drop of the 2 nd LED group (i.e. the second light emitting assembly) is V LED2 The current flowing is I2; as can be seen from the circuit of scheme 1 shown in fig. 4C:
V LED1 +I1·VR1＝V LED2 + I2-VR 2 (formula 3.1)
I total I1+ I2 (formula 3.2)
Substituting (equation 3.2) into (equation 3.1) yields:
in the design of scheme 1, two groups of LEDs with different color temperatures should adopt elements with approximate rated conduction voltage drop, so that V in formula 2.2 LED1 -V LED2 The impact on I1 is negligibly small, and equation 3.3 can be approximated as:
the same can be obtained:
it can be seen that:
therefore, the control module changes the duty ratio of any one of the two paths of output PWM signals, namely, the VR2/VR1 can be changed, and the current proportion of the two LED groups with different color temperatures is changed, so that the light emitting proportion of the two LED groups with different color temperatures is changed, and the color temperature of the light finally output after light mixing is also changed.
The direct current power supply in the scheme 1 is a constant voltage source or a constant current source, and the equations 3.1 and 3.2 are both true, so the above conclusion is correct.
Alternatively, as shown by the dashed boxes in fig. 4A to 4C, a PWM-controlled dual variable equivalent resistance module dual-VR is formed by a circuit in which the equivalent resistance between the terminal 1 and the terminal 2 is VR1, the equivalent resistance between the terminal 4 and the terminal 2 is VR2, and the terminal 3 is a PWM signal receiving terminal. When the duty ratio of the received PWM signal is changed, the resistances of VR1 and VR2 are changed simultaneously, and the change directions are opposite.
As shown by the dashed line box in fig. 4C, the module dual-VR includes two MOSFETs Q1 and Q2, the sources of which are connected to resistors R1B and R2B respectively and then connected to terminal 2, the drains of Q1 and Q2 are connected to terminals 1 and 4 respectively, the gate of Q1 is connected to terminal 3, resistor R1A is connected between terminal 1 and terminal 2, resistor R2A is connected between terminal 4 and terminal 2, resistors R3 and R4 are connected in series between terminal 1 and terminal 2, and the middle point of connection of R3 and R4 is connected to the gate of Q2. When a PWM signal enables Q1 to be conducted at a high level, a source-drain voltage of Q1 is reduced, a gate voltage of Q1 is clamped to a low level, Q1 is cut off, when Q1 is cut off by the PWM signal, a gate voltage of Q2 is a voltage across R4, resistance values of R1A, R3 and R4 are properly designed, R1A < < R3+ R4 is enabled, and voltage drop across R4 is enabled to be higher than an opening threshold value of Q2 at the moment, and Q2 is conducted. It can be seen that Q1, Q2 work in anti-phase.
Let DC Power in FIG. 4C be constant current source, output current is constant at I total . The duty ratio of the PWM signal is recorded as delta, and the conduction voltage drop of the 1 st LED group is recorded as V LED1 The average value of the current flowing through the 1 st LED group is I1, and the conduction voltage drop of the 2 nd LED group is recorded as V LED2 The average value of the current flowing through the 2 nd LED group is I2. When the PWM signal is at high level, Q1 is turned on, Q2 is turned off, and it is noted that the current flowing through the 1 st LED group I1 'is I2', and:
I total = I1 '+ I2' (formula 5.1)
As seen by the circuit, at this time: v LED1 ＝V LED2 + I2'. R2A, derived:
when the PWM signal is low, Q1 is turned off and Q2 is turned on, and it is noted that the current flowing through the 1 st LED group I1 "is I2" since R1A<<R3+ R4, ignoring the current in the R3 and R4 branches at this time, we can: v LED1 +I1”·R1A＝V LED2 Due to I total I1 "+ I2", we conclude that:
the average value of the current flowing through the 1 st LED group in the whole PWM period is defined as:
as can be seen from equations 5.6 and 5.7, when the duty ratio of the PWM signal is changed, the average value of the current flowing through the 1 st LED group and the average value of the current flowing through the 2 nd LED group are changed, and the changed magnitudes are opposite, that is, when the duty ratio δ is increased, I1 is increased, I2 is decreased, and when the duty ratio δ is decreased, I1 is decreased, I2 is increased, so that changing the duty ratio δ of the PWM signal can change the current ratios flowing through the 1 st LED group and the 2 nd LED group, and change the light emitting ratios of the 1 st LED group and the 2 nd LED group, which results in a change in the color temperature of the output light after light mixing.
In the scheme 2, as can also be seen from the formulas 5.6 and 5.7, when the PWM duty ratio δ is determined, changing the resistance value of R1A or R2A can also change I1 and I2, and the change is opposite in magnitude. Once the design of the control module is determined, the control module can not change in mass production, namely, in the application of stepped color temperature adjustment, the duty ratio delta value of each gear output by the control module can not change after being determined, so that the control module is favorable for mass production. However, because the parameters of the LED elements are different in batch, different bins of the LEDs with the same specification are usually distinguished according to their conduction voltage drop or color temperature, and in order to improve the supply conditions of the elements during batch production, the LED elements with different bins need to be used to manufacture the same lamp product. Whether the LED conduction voltage drop or the slight difference of the color temperature of the elements may cause the deviation of the output color temperature of the lamp. When these lamps with color temperature deviation are installed in a space, the color temperature of the lamps can be disordered and the appearance of the lamps can be affected. After the invention is adopted, aiming at the LED elements of different bins, the duty ratio of the PWM signal output by the control module can be not changed, and the output color temperature of the lamp can be accurately adjusted only by determining a group of R1A and R2A according to the parameters of the LEDs of the different bins, so that the lamp can output light with a target color temperature with higher consistency, and the production and logistics management is simplified.
In the scheme 1, as can be seen from the formulas 2.3 and 3.6, when the duty ratios δ 1 and δ 2 of the PWM signals are both determined, the RA resistance in VR1 or VR2 is changed, that is, the equivalent resistance of the corresponding module is changed, so that the light emitting ratios of the two groups of LEDs are changed, and the output color temperature of the lamp is changed.
Referring to fig. 4C, the input of the control module of the present invention is connected to the multi-position switch, the control module determines the duty ratio of the output PWM signal according to the detected position of the switch, and if the output PWM duty ratios at different switch positions are different, the light emitting device with multi-step color temperature output controlled by the switch is formed.
Referring to fig. 5A, the embodiment of the invention further provides a color temperature adjusting circuit for controlling the mixed color temperature of at least 2 sets of light emitting components. The color temperature adjusting circuit 500 includes: a color temperature adjusting module 510 and a control module 520. The color temperature adjusting module is connected with the at least two groups of light-emitting components in series respectively and is used for adjusting the current flowing through each light-emitting component. The control module is connected with the color temperature adjusting module and outputs a pulse width adjustable control signal to control the equivalent output resistor of the color temperature adjusting module so as to realize the adjustable mixed color temperature of the at least 2 groups of light-emitting components.
Further, referring to fig. 5B, the color temperature adjustment module 510 includes at least 2 variable resistance modules; each variable resistance module is connected with each light-emitting component in series in a one-to-one correspondence manner; and the adjustable end of the variable resistance module is connected with the output end of the control module.
Referring to fig. 5C, in an embodiment of the invention, the color temperature adjusting circuit 500 further includes: a communication module 530. The communication module 530 is communicatively connected to the control module and configured to receive a duty ratio setting instruction of the pulse width adjustable control signal.
The embodiment of the invention also provides a color temperature adjusting chip, which comprises the color temperature adjusting circuit.
The embodiment of the invention also provides LED equipment, and the LED equipment comprises the color temperature adjustable light-emitting device.
The embodiment of the invention also provides LED equipment, and the LED equipment comprises the color temperature adjusting circuit.
The embodiment of the invention also provides LED equipment, and the LED equipment comprises the color temperature adjusting chip.
The invention can finely adjust the resistance value of the related resistor in the variable resistor module, can finely adjust the color temperature under the condition of not moving the control module, can ensure the consistency of the output target color temperature of the lamp when adopting the LED elements of different bins, is beautiful and high in quality, and is convenient for the management of production and supply chains.
The invention adopts PWM signal to control the equivalent impedance of the variable resistance module to change, so as to change the current of the LED groups with different color temperatures, thus achieving the purpose of color temperature adjustment.
The single-path PWM signal control scheme adopted by the invention simplifies the control mode, makes the design of the control module easier to realize and has lower control error probability.
In conclusion, the present invention effectively overcomes various disadvantages of the prior art and has high industrial utilization value.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (18)
1. A color temperature tunable light emitting device, comprising:
a first light emitting assembly;
the second light-emitting component is connected with the first light-emitting component in parallel;
the color temperature adjusting module is connected with the first light emitting assembly and the second light emitting assembly in series and adjusts currents respectively flowing through the first light emitting assembly and the second light emitting assembly by setting resistance values of resistors of the color temperature adjusting module;
and the control module is connected with the color temperature adjusting module and outputs a pulse width adjustable control signal to control the equivalent output resistor of the color temperature adjusting module so as to realize adjustable mixed color temperature of the first light-emitting component and the second light-emitting component.
2. The color temperature tunable light emitting device according to claim 1, wherein: the color temperature adjusting module comprises 2 variable resistance modules; the other variable resistance module is connected with the second light-emitting component in series; and the adjustable end of the variable resistance module is connected with the output end of the control module.
3. The color temperature tunable light emitting device according to claim 2, wherein: the control module is provided with 2 output ends for respectively outputting 1 path of pulse width adjustable control signals; and 2 output ends of the control module are correspondingly connected with the adjustable ends of the 2 variable resistance modules one by one.
4. The color temperature tunable light emitting device according to claim 3, wherein: the color temperature adjusting module comprises a first control end, a second control end, a first positive end, a second positive end and a negative end; the first control end is an adjustable end of the variable resistance module, and the first positive end is a positive end of the adjustable resistance module; the second control end is an adjustable end of the other variable resistance module, and the second positive end is a positive end of the other adjustable resistance module; the negative ends are the negative ends of the 2 variable resistance modules; the first control end is connected with one output end of the control module, and the second control end is connected with the other output end of the control module; the first positive terminal is connected with the negative electrode of the first light-emitting component, and the second positive terminal is connected with the negative electrode of the second light-emitting component; the negative electrode end is used for being connected with a negative electrode of a power supply; the positive electrode of the first light-emitting assembly is connected with the positive electrode of the power supply, and the positive electrode of the second light-emitting assembly is connected with the positive electrode of the power supply.
5. The color temperature tunable light emitting device according to claim 2, wherein: the color temperature adjusting module also comprises a voltage dividing module; the voltage division module is connected with the variable resistance module in parallel, and the output end of the voltage division module is connected with the adjustable end of the other variable resistance module; and the adjustable end of the variable resistance module is connected with the output end of the control module.
6. The color temperature tunable light emitting device according to claim 5, wherein: the color temperature adjusting module comprises a first control end, a first positive end, a second positive end and a negative end; the first control end is an adjustable end of the variable resistance module, and the first positive end is a positive end of the adjustable resistance module; the negative ends are the negative ends of the 2 variable resistance modules; the first control end is connected with the output end of the control module; the first positive terminal is connected with the negative electrode of the first light-emitting component, and the second positive terminal is connected with the negative electrode of the second light-emitting component; the negative electrode end is used for being connected with a negative electrode of a power supply; the positive electrode of the first light-emitting assembly is connected with the positive electrode of the power supply, and the positive electrode of the second light-emitting assembly is connected with the positive electrode of the power supply.
7. The color temperature tunable light emitting device according to claim 2, wherein: the variable resistance module comprises an MOS tube, a first resistor, a second resistor, a positive terminal, a negative terminal and an adjustable terminal; the grid electrode of the MOS tube is connected with the adjustable end, the source electrode of the MOS tube is connected with one end of the second resistor, and the drain electrode of the MOS tube is connected with the positive end; one end of the first resistor is connected with the drain electrode of the MOS tube, and the other end of the first resistor is connected with the cathode end; the other end of the second resistor is connected with the negative electrode end; the adjustable end is connected with the output end of the control module.
8. The color temperature tunable light emitting device according to claim 1, wherein: the first light emitting assembly comprises a set of LED circuits; the second light emitting assembly comprises a set of LED circuits; the first light emitting assembly and the second light emitting assembly have different color temperatures.
9. The color temperature tunable light emitting device according to claim 7, wherein: the control module outputs a pulse width adjustable control signal with a duty ratio delta to control the equivalent output resistance of a variable resistance module in the color temperature adjusting module to be VR:
when the constant current source supplies power to the variable resistance module, the current flowing through the variable resistance module is constant and is I;
when the variable resistance module receives the high level of the pulse width adjustable control signal, the MOS tube in the variable resistance module is conducted, the equivalent resistance between the positive end and the negative end of the variable resistance module is that the first resistor RA and the second resistor RB are connected in parallel, namely the resistance value of the equivalent resistance is
At this time, the voltage between the positive electrode end and the negative electrode end of the variable resistance module is U '═ I · R';
when the variable resistance module receives the low level of the pulse width adjustable control signal, the MOS tube in the variable resistance module is turned off, only the first resistor RA is connected between the positive terminal and the negative terminal of the variable resistance module, and the voltage between the positive terminal and the negative terminal of the variable resistance module is U ═ I · RA at the moment;
the average voltage between the positive terminal and the negative terminal of the variable resistance module in the whole PWM period is as follows:
in the whole PWM period, the average resistance value between the positive terminal and the negative terminal of the variable resistance module is the equivalent output resistance VR of the variable resistance module.
10. The color temperature tunable light emitting device according to claim 7, wherein: the control module outputs a pulse width adjustable control signal with a duty ratio delta to control the equivalent output resistance of a variable resistance module in the color temperature adjusting module to be VR:
when the constant voltage source supplies power to the variable resistance module, the voltage between the positive terminal and the negative terminal of the variable resistance module is constant and is U;
when the variable resistance module receives the high level of the pulse width adjustable control signal, the current flowing into the positive end and the negative end of the variable resistance module is
When the variable resistance module receives the low level of the pulse width adjustable control signal, the current flowing into the positive end and the negative end of the variable resistance module is
The average value of the current flowing into the positive terminal and the negative terminal of the variable resistance module in the whole PWM period is as follows:
in the whole PWM period, the average resistance value between the positive terminal and the negative terminal of the variable resistance module is the equivalent output resistance VR of the variable resistance module.
11. The color temperature tunable light emitting device according to claim 7, wherein: the control module outputs a pulse width adjustable control signal with a duty ratio delta 1 to control the equivalent output resistance of one variable resistance module in the color temperature adjusting module to be VR1, and outputs a pulse width adjustable control signal with a duty ratio delta 2 to control the equivalent output resistance of the other variable resistance module in the color temperature adjusting module to be VR2, so that the equivalent output resistance of the color temperature adjusting module is VR;
when the current is controlled by a constant current source I total When the color temperature adjustable light-emitting device is powered, the voltage drop of the first light-emitting component is V LED1 The average current flowing through the first light-emitting component is I1; the voltage drop of the second light-emitting component is V LED2 The average current flowing through the second light-emitting component is I2;
according to the relational expression
Therefore, the control module changes the duty ratio of any one of the two pulse width adjustable control signals, i.e., changes VR2/VR1, and further changes the current ratios respectively flowing through the first light-emitting assembly and the second light-emitting assembly, so that the light-emitting ratios of the first light-emitting assembly and the second light-emitting assembly are changed, and the mixed color temperature of the first light-emitting assembly and the second light-emitting assembly is changed.
12. A color temperature adjustment circuit for controlling a mixed color temperature of at least 2 sets of light emitting elements, the color temperature adjustment circuit comprising:
the color temperature adjusting module is respectively connected with the at least two groups of light-emitting components in series and is used for adjusting the current flowing through each light-emitting component;
and the control module is connected with the color temperature adjusting module and outputs a pulse width adjustable control signal to control the equivalent output resistor of the color temperature adjusting module so as to realize that the mixed color temperature of at least 2 groups of light-emitting components is adjustable.
13. The color temperature adjustment circuit of claim 12, wherein: the color temperature adjusting module comprises at least 2 variable resistance modules; each variable resistance module is connected with each light-emitting component in series in a one-to-one correspondence manner; and the adjustable end of the variable resistance module is connected with the output end of the control module.
14. The color temperature adjustment circuit of claim 12, further comprising:
and the communication module is in communication connection with the control module and is used for receiving a duty ratio setting instruction of the pulse width adjustable control signal.
15. A color temperature adjustment chip, characterized in that the color temperature adjustment chip comprises the color temperature adjustment circuit of any one of claims 12 to 14.
16. An LED apparatus, characterized in that the LED apparatus comprises the color temperature tunable light emitting device of any one of claims 1 to 11.
17. An LED device characterized in that it comprises a color temperature adjusting circuit according to any one of claims 12 to 14.
18. An LED device, characterized in that the LED device comprises the color temperature adjusting chip of claim 15.
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| CN118413916A (en) * | 2024-07-04 | 2024-07-30 | 深圳市晟大光电有限公司 | Light source color mixing circuit, method and electronic equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN118413916A (en) * | 2024-07-04 | 2024-07-30 | 深圳市晟大光电有限公司 | Light source color mixing circuit, method and electronic equipment |
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