CN108364613A - LED backlight drive circuit, LED backlight, television terminal - Google Patents
LED backlight drive circuit, LED backlight, television terminal Download PDFInfo
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- CN108364613A CN108364613A CN201810121747.0A CN201810121747A CN108364613A CN 108364613 A CN108364613 A CN 108364613A CN 201810121747 A CN201810121747 A CN 201810121747A CN 108364613 A CN108364613 A CN 108364613A
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- 239000003990 capacitor Substances 0.000 claims description 56
- 238000004804 winding Methods 0.000 claims description 42
- 230000005669 field effect Effects 0.000 claims description 36
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 238000000034 method Methods 0.000 description 10
- 238000010586 diagram Methods 0.000 description 7
- 230000007423 decrease Effects 0.000 description 6
- 230000015556 catabolic process Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 238000007599 discharging Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/10—Controlling the intensity of the light
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- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
A kind of LED backlight drive circuit of the application offer, LED backlight, television terminal.The circuit includes motherboard power supply, backlight electric power and BOOST circuits；Motherboard power supply exports the first predeterminated voltage, and backlight electric power exports the second predeterminated voltage；BOOST circuits are arranged between motherboard power supply and backlight electric power, for being adjusted an output voltage of backlight electric power to target voltage according to the first predeterminated voltage when receiving externally input control signal, so that another output voltage of backlight electric power is the sum of the second predeterminated voltage and target voltage；Target voltage is more than the first predeterminated voltage.The pressure voltage of each device is more than or equal to target voltage in the present embodiment BOOST circuits, reduces the pressure voltage of each device in BOOST circuits, can improve the service life of each device, while can reduce production cost.Also, the present embodiment can also reduce the conduction impedance of each device and reduce thermal losses.
Description
Technical Field
The application relates to the technical field of power supplies, in particular to an LED backlight driving circuit, an LED backlight and a television terminal.
Background
Fig. 1 is a circuit diagram of an LED backlight driving circuit provided in the related art. Referring to fig. 1, the transformer in the LED backlight driving circuit includes two secondary windings. The winding N13, the diode D11 and the capacitor C11 form a main board power supply, and 12V voltage is provided for the main board circuit. The winding N12, the diode D12 and the capacitor C12 constitute a backlight power supply, which outputs a voltage of 60V. Typically, the driving voltage of the LED is about 80V, and a BOOST circuit is added between the backlight power supply and the LED. Referring to fig. 1, in the BOOST circuit, the fet V12 is connected to the 60V voltage output terminal through the inductor L11, and when the fet V12 is turned on, the 60V voltage output terminal is grounded through the inductor L11 and the fet V12, that is, the inductor L11 is charged. When the fet V12 is turned off, the potential of the 60V voltage output terminal plus the inductor L11 charges the capacitor C13 through the diode D13, so that the voltage of the capacitor C13 becomes 80V and is output to the LED.
For the FET V12 and the capacitor C13 in the BOOST circuit, the withstand voltage value needs to be more than 80V. With the increase of the output voltage of the LED backlight driving circuit, the withstand voltage of the fet V12 and the capacitor C13 needs to be increased, which not only reduces the service life of the fet V12 and the capacitor C13, but also increases the production cost. When the current is not changed, the on-resistance of the fet V12 increases, which increases the amount of heat generated, resulting in a high temperature of the LED backlight driving circuit.
Disclosure of Invention
In view of this, the present application provides an LED backlight driving circuit, an LED backlight, and a television terminal, which are used to solve the problems of short service life and high manufacturing cost of the backlight driving circuit caused by too high withstand voltage values of a part of field effect transistors and a part of capacitors in the backlight driving circuit provided by the related art.
Specifically, the method is realized through the following technical scheme:
in a first aspect, an embodiment of the present application provides an LED backlight driving circuit, where the circuit includes a main board power supply, a backlight power supply, and a BOOST circuit; the main board power supply outputs a first preset voltage, and the backlight power supply outputs a second preset voltage;
the BOOST circuit is arranged between the mainboard power supply and the backlight power supply and used for adjusting the voltage at one output end of the backlight power supply to a target voltage according to the first preset voltage when receiving an externally input control signal so as to enable the voltage at the other output end of the backlight power supply to be the sum of the second preset voltage and the target voltage;
wherein the target voltage is greater than the first preset voltage.
Optionally, the BOOST circuit includes: the device comprises an inductor, a first field effect transistor, a first controller, a first diode and a first capacitor;
the first end of the inductor is connected with one output end of the mainboard power supply, and the other output end of the mainboard power supply is grounded; the second end of the inductor is respectively connected with the drain electrode of the first field effect transistor and the anode of the first diode;
the grid electrode of the first field effect transistor is connected with the first controller, and the source electrode of the first field effect transistor is grounded;
the anode of the first capacitor is respectively connected with the cathode of the first diode and one output end of the backlight power supply, and the cathode is grounded.
Optionally, the withstand voltage values of the first field effect transistor and the first capacitor are greater than or equal to the target voltage.
Optionally, the BOOST circuit further comprises a first resistor; the first resistor is connected between the source electrode of the first field effect transistor and the ground in series;
and the first input end of the first controller is connected with the source electrode of the first field effect transistor.
Optionally, the BOOST circuit further comprises a second resistor; the second resistor is connected between the first output end of the LED backlight driving circuit and the ground in series; the voltage between the first output end of the LED backlight driving circuit and the other output end of the backlight power supply is the sum of the second preset voltage and the target voltage;
the second input end of the first controller is connected with one end, far away from the ground, of the second resistor.
Optionally, the LED backlight driving circuit includes a second field effect transistor and a second controller; and the grid electrode of the second field effect transistor is connected with the second controller, the drain electrode of the second field effect transistor is connected with the first output end of the LED backlight driving circuit, and the source electrode of the second field effect transistor is grounded.
Optionally, the main board power supply includes a third field effect transistor and a third controller, a primary winding and a first secondary winding of a transformer, a second diode, and a second capacitor;
the different-name end of the primary winding of the transformer is connected with the anode of the direct-current power supply, and the same-name end of the primary winding of the transformer is connected with the drain electrode of the third field-effect tube;
the grid electrode of the third field effect transistor is connected with the third controller, and the source electrode of the third field effect transistor is connected with the negative electrode of the direct-current power supply;
the cathode of the second capacitor is respectively connected with the synonym end of the first secondary winding and one output end of the main board power supply;
and the anode of the second diode is connected with the dotted terminal of the first secondary winding, and the cathode of the second diode is respectively connected with the anode of the second capacitor and the other output terminal of the main board power supply.
Optionally, the backlight power supply and the main board power supply share a third field effect transistor, a third controller and a primary winding of a transformer, and the backlight power supply further includes a third capacitor, a third diode and a second secondary winding of the transformer;
the cathode of the third capacitor is respectively connected with the synonym end of the second secondary winding and one output end of the backlight power supply;
and the anode of the third diode is connected with the dotted terminal of the second secondary winding, and the cathode of the third diode is respectively connected with the anode of the third capacitor and the other output terminal of the backlight power supply.
In a second aspect, an embodiment of the present application provides an LED backlight, including the LED backlight driving circuit described in the first aspect.
In a third aspect, an embodiment of the present application provides a television terminal, including: the LED backlight of the second aspect.
According to the technical scheme, the BOOST circuit is arranged between the main board power supply and the backlight power supply, and one output end of the backlight power supply is adjusted to the target voltage according to the first preset voltage output by the main board power supply, so that the other output end of the backlight power supply outputs the sum of the second preset voltage and the target voltage. It can be seen that in this embodiment, the withstand voltage value of each device in the BOOST circuit is greater than or equal to the target voltage, and does not need to be greater than the sum of the second preset voltage and the target voltage, that is, the withstand voltage value of each device in the BOOST circuit is reduced in this embodiment, and the service life of each device can be prolonged. In addition, in the embodiment, a device with a smaller voltage withstanding value can be selected, so that the production cost of the LED backlight driving circuit is reduced. Further, as the breakdown voltage value decreases, the on-resistance of each device also decreases, and the thermal loss can be reduced.
Drawings
Fig. 1 is a circuit diagram of an LED backlight driving circuit provided in the related art;
fig. 2 is a circuit diagram of an LED backlight driving circuit according to an embodiment of the present application;
fig. 3 is a circuit diagram of an LED backlight driving circuit according to another embodiment of the present application.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.
Fig. 1 shows a circuit diagram of an LED backlight driving circuit provided in the related art. Referring to fig. 1, the main board power supply in the LED backlight driving circuit only supplies 12V to the main board. The backlight power supply provides 60V voltage for the LED, and in order to meet the requirement that the input voltage of the LED is 80V, the BOOST circuit needs to adjust the 60V voltage to 80V voltage. In the adjusting process, the FET V12 and the capacitor C13 in the BOOST circuit bear the voltage of 60V at the lowest and bear the voltage of 80V at the highest. In practical application, the voltage withstanding values of the field effect transistor V12 and the capacitor C13 are required to be more than 80V. It can be understood that as the output voltage of the LED backlight driving circuit increases, the withstand voltages of the fet V12 and the capacitor C13 also increase, which not only reduces the service lives of the fet V12 and the capacitor C13, but also increases the production cost. When the current is not changed, the on-resistance of the fet V12 increases, which increases heat generation and reduces the lifetime of the fet V12.
In order to solve the above problem, an embodiment of the present application provides an LED backlight driving circuit, and fig. 2 is a circuit diagram of the LED backlight driving circuit according to an embodiment of the present application. Referring to fig. 2, the LED backlight driving circuit includes: motherboard power supply 100, backlight power supply 200, and BOOST circuit 300. The main board power supply 100 outputs a first preset voltage, and the backlight power supply 200 outputs a second preset voltage;
the BOOST circuit 300 is disposed between the main board power supply 100 and the backlight power supply 200, and is configured to adjust a voltage at one output terminal of the backlight power supply 200 to a target voltage according to a first preset voltage when receiving an externally input control signal, so that the voltage at the other output terminal of the backlight power supply 200 is a sum of a second preset voltage and the target voltage; the target voltage is greater than a first preset voltage.
It should be noted that, in the present embodiment, the first preset voltage may be 12V. Of course, a person skilled in the art may adjust the value of the first preset voltage according to the requirement of the motherboard, for example, 5V, which is not limited herein.
Similarly, the second predetermined voltage may be 60V in this embodiment. Of course, a person skilled in the art may adjust the value of the second preset voltage according to the input voltage of the LED, for example, 80V, which is not limited herein.
It should be noted that the externally input control signal is used to control a switching device, such as a field effect transistor, in the BOOST circuit 300. The externally input control signal may be a controller in the LED backlight driving circuit or a controller in the motherboard, and the scheme of the present application may be implemented. In practical applications, the externally input control signal may be a PWM signal, and the target voltage may be adjusted by adjusting a duty ratio of the PWM signal. Since the PWM control technique is already mature, it will not be described in detail here.
As can be seen from the above technical solutions, in the embodiment of the present application, the BOOST circuit 300 is disposed between the motherboard power supply 100 and the backlight power supply 200, and one output terminal of the backlight power supply 200 is adjusted to the target voltage according to the first preset voltage output by the motherboard power supply 100, so that the voltage at the other output terminal of the backlight power supply 200 is the sum of the second preset voltage and the target voltage. It can be seen that in this embodiment, the withstand voltage value of each device in the BOOST circuit is greater than or equal to the target voltage, and does not need to be greater than the sum of the second preset voltage and the target voltage, that is, the withstand voltage value of each device in the BOOST circuit is reduced in this embodiment, and the service life of each device can be prolonged. In addition, in the embodiment, a device with a smaller voltage withstanding value can be selected, so that the production cost of the LED backlight driving circuit is reduced. Further, as the breakdown voltage value decreases, the on-resistance of each device also decreases, and thus the heat loss can be reduced.
With continued reference to fig. 2, in an embodiment of the present application, the main board power supply 100 includes a third fet V3, a third controller DR3, a primary winding N11 and a first secondary winding N12 of a transformer T, a second diode D2, and a second capacitor C2. Wherein,
the synonym terminal of the primary winding N11 of the transformer T (the upper end of the primary winding N11 in FIG. 2) is connected with the positive electrode (indicated by a plus sign in FIG. 2) of the direct-current power supply 400, and the homonym terminal (the lower end of the primary winding N11 in FIG. 2 is marked by a plus sign) is connected with the drain electrode of the third field-effect transistor V3;
the gate of the third fet V3 is connected to the third controller DR3, and the source is connected to the negative electrode (denoted by "-" in fig. 2) of the dc power supply 400;
the cathode (the lower end of C2 in fig. 2) of the second capacitor C2 is respectively connected with the synonym terminal (the lower end of N12 in fig. 2) of the first secondary winding N12 and one output terminal a of the main board power supply 100;
an anode (left end of D2 in fig. 2) of the second diode D2 is connected to the same-name end (upper end of N12 in fig. 2) of the first secondary winding N12, and a cathode (right end of D2 in fig. 2) of the second diode D2 is connected to an anode (upper end of C2 in fig. 2) of the second capacitor C2 and another output end B of the main board power supply 100, respectively.
The working process of the motherboard power supply 100 includes: the third controller DR3 outputs a control signal to the gate of the third fet V3 to control the third fet V3 to turn on or off, so as to connect the negative terminal of the dc power supply 400 to the end of the transformer T that is the same name as the primary winding N11, and at this time, the dc power supply 400 charges the primary winding N11.
According to the transformer principle, the dotted terminal of the first secondary winding N12 of the transformer T induces a first preset voltage, and since the voltage induced by the first secondary winding N12 is greater than the anode voltage of the second capacitor C2, that is, the anode voltage of the second diode D2 is greater than the cathode voltage, the second diode D2 is turned on, so that the purpose that the dc power supply 400 charges the main board power supply 100 is achieved. The duty ratio of the control signal output by the third controller DR3 can be adjusted according to the first preset voltage and the discharge speed of the second capacitor C2, which will not be described in detail herein.
In this embodiment, the output terminal a and the output terminal B are respectively connected to the positive electrode and the negative electrode of each device in the motherboard, so as to achieve the purpose of providing the motherboard with the first preset voltage by the motherboard power supply 100.
With continued reference to fig. 2, in an embodiment of the present invention, the backlight power supply 200 and the main board power supply 100 share the third fet V3, the third controller DR3, and the primary winding N11 of the transformer T. In addition, the backlight power supply 200 further includes a third capacitor C3, a third diode D3, and a second secondary winding N13 of the transformer T;
the cathode (the lower end of C3 in fig. 2) of the third capacitor C3 is respectively connected with the synonym terminal (the lower end of N13 in fig. 2) of the second secondary winding N13 and one output terminal C of the backlight power supply 200;
the anode (left end of D3 in fig. 2) of the third diode D3 is connected to the same name end (upper end of N13 in fig. 2, marked "·") of the second secondary winding N13, and the cathode is connected to the anode of the third capacitor C3 and the other output end D of the backlight power supply 200, respectively.
The operation process of the backlight power supply 200 includes: the third controller DR3 outputs a control signal to the gate of the third fet V3 to control the third fet V3 to turn on or off, so as to connect the negative terminal of the dc power supply 400 to the end of the transformer T that is the same name as the primary winding N11, and at this time, the dc power supply 400 charges the primary winding N11.
According to the transformer principle, the end with the same name of the second secondary winding N13 of the transformer T induces a second preset voltage, and since the voltage induced by the second secondary winding N13 is greater than the voltage of the anode of the third capacitor C3, that is, the voltage of the anode of the third diode D3 is greater than the voltage of the cathode, the third diode D3 is turned on, so that the purpose that the dc power supply 400 charges the backlight power supply 200 is achieved.
With continued reference to fig. 2, in an embodiment of the present application, the BOOST circuit 300 includes: the inductor L1, the first fet V1, the first controller DR1, the first diode D1, and the first capacitor C1. A first end (left end of L1 in fig. 2) of the inductor L1 is connected to an output end B of the motherboard power supply 100, and an output end a of the motherboard power supply 100 is grounded to GND; a second terminal (right end of L1 in fig. 2) of the inductor L1 is connected to the drain of the first fet V1 and the anode of the first diode D1 (left end of D1 in fig. 2), respectively;
the grid electrode of the first field effect transistor V1 is connected with the first controller DR1, and the source electrode is grounded GND;
the anode (the upper end of C1 in fig. 2) of the first capacitor C1 is connected to the cathode of the first diode D1 and an output terminal C of the backlight power supply 200, and the cathode is grounded to GND.
The operation process of the BOOST circuit 300 includes: the first controller DR1 outputs a control signal to the gate of the first fet V1 to control the first fet V1 to turn on or off.
When the first fet V1 is turned on, the second terminal of the inductor L1 and the ground GND are turned on. A loop is formed among the second capacitor C2, the inductor L1, the first fet V1, and the ground GND, that is, the main board power supply 100 charges the inductor L1, and during the charging process, the voltage (almost equal to zero) at the anode of the first diode D1 is lower than the cathode voltage, and at this time, the main board power supply 100 cannot charge the first capacitor C1. It can be understood that during the charging process, the voltage at the first terminal of the inductor L1 is higher than the voltage at the second terminal.
When the first fet V1 is turned off, the connection between the second terminal of the inductor L1 and the ground GND is disconnected, and the inductor L1 discharges. Due to the characteristics of the inductor, the inductor L1 can be equivalent to a battery with a first terminal voltage lower than a second terminal voltage in the discharging process, and a second capacitor C2 is further superimposed, at this time, the voltage of the anode of the first diode D1 is the sum of the anode voltage of the second capacitor C2 and the voltages of the two terminals of the inductor L1, and is much larger than the voltage of the cathode of the second capacitor C2, that is, the second capacitor C2 and the inductor L1 charge the first capacitor C1.
The first controller DR1 controls the first fet V1 to repeatedly turn on and off, and continuously charges the first capacitor C1, thereby stabilizing the voltage of the first capacitor C1 at the target voltage.
Since the anode of the first capacitor C1 is connected to the output terminal C of the backlight power supply 200, the voltage at the output terminal C can be stabilized at the target voltage. In conjunction with the pumping action of the third capacitor C3, the voltage at the output terminal D of the backlight power supply 200 may be the sum of the second preset voltage and the target voltage.
In the embodiment of the present application, the voltage withstanding values of the first fet V1 and the first capacitor C1 in the BOOST circuit 300 are only required to be greater than or equal to the target voltage, and compared with fig. 1, the voltage withstanding values of the first fet V1 and the first capacitor C1 are greatly reduced (from 80V to 20V), which is beneficial to improving the service life thereof. As the breakdown voltage value decreases, the on-resistance of the first field effect transistor V1 also decreases, and thus the heat loss can be reduced.
Fig. 3 is a circuit diagram of an LED backlight driving circuit according to another embodiment of the present application. Referring to fig. 3, the BOOST circuit 300 of the LED backlight driving circuit further includes a first resistor R1 on the basis of the LED backlight driving circuit shown in fig. 2. The first resistor R1 is connected in series between the source of the first fet V1 and ground GND. In this case, the first input terminal of the first controller DR1 is connected to the source of the first fet V1. In this way, in the present embodiment, the first controller DR1 may adjust the duty ratio of the output control signal according to the voltage or current at the upper end of the first resistor R1, so as to adjust the target voltage of the first capacitor C1, which is beneficial to improve the control accuracy of the target voltage through feedback adjustment.
With continued reference to fig. 3, the BOOST circuit 300 of the LED backlight driving circuit further includes a second resistor R2 on the basis of the LED backlight driving circuit shown in fig. 2. The second resistor R2 is connected in series between the first output terminal (LED-) of the LED backlight driving circuit and ground GND. Wherein, the voltage between the first output terminal (LED-) and the output terminal D of the backlight power supply 200 is the sum of the second preset voltage and the target voltage. A second input terminal of the first controller DR1 is connected to one end of the second resistor R2, which is far from the ground GND. Thus, in this embodiment, the first controller DR1 may adjust the duty ratio of the output control signal according to the current flowing through the second resistor R2, so as to adjust the target voltage of the first capacitor C1 and the voltage at the output terminal D of the backlight power supply 200, i.e., adjust the input voltage of the LED, thereby achieving the purpose of accurately controlling the brightness of the LED.
In one embodiment, with continued reference to fig. 3, the LED backlight driving circuit includes a second fet V2 and a second controller DR 2. The gate of the second fet V2 is connected to the second controller DR2, the drain is connected to the first output terminal (LED-) of the LED backlight driver circuit, and the source is grounded. It can be understood that, when the LED backlight driving circuit includes the second resistor R2, the drain of the second fet V2 is connected to the end of the second resistor R2 away from the ground GND. The second controller DR2 can control the on/off of the second fet V2, so as to control the LED to emit light or turn off.
The embodiment of the application also provides an LED backlight lamp, which comprises the LED backlight driving circuit in each embodiment.
An embodiment of the present application further provides a television terminal, where the television terminal includes: an LED backlight as described in the above embodiments.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.
Claims (10)
1. The LED backlight driving circuit is characterized by comprising a main board power supply, a backlight power supply and a BOOST circuit; the main board power supply outputs a first preset voltage, and the backlight power supply outputs a second preset voltage;
the BOOST circuit is arranged between the mainboard power supply and the backlight power supply and used for adjusting the voltage at one output end of the backlight power supply to a target voltage according to the first preset voltage when receiving an externally input control signal so as to enable the voltage at the other output end of the backlight power supply to be the sum of the second preset voltage and the target voltage;
wherein the target voltage is greater than the first preset voltage.
2. The LED backlight driver circuit of claim 1, wherein the BOOST circuit comprises: the device comprises an inductor, a first field effect transistor, a first controller, a first diode and a first capacitor;
the first end of the inductor is connected with one output end of the mainboard power supply, and the other output end of the mainboard power supply is grounded; the second end of the inductor is respectively connected with the drain electrode of the first field effect transistor and the anode of the first diode;
the grid electrode of the first field effect transistor is connected with the first controller, and the source electrode of the first field effect transistor is grounded;
the anode of the first capacitor is respectively connected with the cathode of the first diode and one output end of the backlight power supply, and the cathode is grounded.
3. The LED backlight driving circuit according to claim 2, wherein a withstand voltage value of the first field effect transistor and the first capacitor is greater than or equal to the target voltage.
4. The LED backlight driver circuit of claim 2, wherein the BOOST circuit further comprises a first resistor; the first resistor is connected between the source electrode of the first field effect transistor and the ground in series;
and the first input end of the first controller is connected with the source electrode of the first field effect transistor.
5. The LED backlight driver circuit of claim 2, wherein the BOOST circuit further comprises a second resistor; the second resistor is connected between the first output end of the LED backlight driving circuit and the ground in series; the voltage between the first output end of the LED backlight driving circuit and the other output end of the backlight power supply is the sum of the second preset voltage and the target voltage;
the second input end of the first controller is connected with one end, far away from the ground, of the second resistor.
6. The LED backlight driving circuit according to claim 1, wherein the LED backlight driving circuit comprises a second field effect transistor and a second controller; and the grid electrode of the second field effect transistor is connected with the second controller, the drain electrode of the second field effect transistor is connected with the first output end of the LED backlight driving circuit, and the source electrode of the second field effect transistor is grounded.
7. The LED backlight driving circuit according to claim 1, wherein the main board power supply comprises a third FET and a third controller, a primary winding and a first secondary winding of a transformer, a second diode and a second capacitor;
the different-name end of the primary winding of the transformer is connected with the anode of the direct-current power supply, and the same-name end of the primary winding of the transformer is connected with the drain electrode of the third field-effect tube;
the grid electrode of the third field effect transistor is connected with the third controller, and the source electrode of the third field effect transistor is connected with the negative electrode of the direct-current power supply;
the cathode of the second capacitor is respectively connected with the synonym end of the first secondary winding and one output end of the main board power supply;
and the anode of the second diode is connected with the dotted terminal of the first secondary winding, and the cathode of the second diode is respectively connected with the anode of the second capacitor and the other output terminal of the main board power supply.
8. The LED backlight driving circuit of claim 7, wherein the backlight power supply and the main board power supply share a third FET and a third controller, a primary winding of a transformer, and further comprising a third capacitor, a third diode, and a second secondary winding of the transformer;
the cathode of the third capacitor is respectively connected with the synonym end of the second secondary winding and one output end of the backlight power supply;
and the anode of the third diode is connected with the dotted terminal of the second secondary winding, and the cathode of the third diode is respectively connected with the anode of the third capacitor and the other output terminal of the backlight power supply.
9. An LED backlight comprising the LED backlight driving circuit according to any one of claims 1 to 8.
10. A television terminal, characterized in that the television terminal comprises: the LED backlight of claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810121747.0A CN108364613B (en) | 2018-02-07 | 2018-02-07 | LED backlight drive circuit, LED backlight lamp and television terminal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810121747.0A CN108364613B (en) | 2018-02-07 | 2018-02-07 | LED backlight drive circuit, LED backlight lamp and television terminal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108364613A true CN108364613A (en) | 2018-08-03 |
| CN108364613B CN108364613B (en) | 2020-03-06 |
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| CN201810121747.0A Active CN108364613B (en) | 2018-02-07 | 2018-02-07 | LED backlight drive circuit, LED backlight lamp and television terminal |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112785971A (en) * | 2020-03-18 | 2021-05-11 | 海信视像科技股份有限公司 | Display device and negative-pressure step power supply circuit |
| CN115459411A (en) * | 2022-11-10 | 2022-12-09 | 荣耀终端有限公司 | Power supply device and terminal equipment |
| US11783788B2 (en) | 2020-03-18 | 2023-10-10 | Hisense Visual Technology Co., Ltd. | Display apparatus and display control method |
| US11825577B2 (en) | 2020-08-24 | 2023-11-21 | Hisense Visual Technology Co., Ltd. | Display apparatus and step power circuit |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112785971A (en) * | 2020-03-18 | 2021-05-11 | 海信视像科技股份有限公司 | Display device and negative-pressure step power supply circuit |
| CN113436571A (en) * | 2020-03-18 | 2021-09-24 | 海信视像科技股份有限公司 | Display device and power supply circuit |
| CN112785971B (en) * | 2020-03-18 | 2022-03-18 | 海信视像科技股份有限公司 | Display device and negative-pressure step power supply circuit |
| CN113436571B (en) * | 2020-03-18 | 2022-10-18 | 海信视像科技股份有限公司 | Display device and power supply circuit |
| US11783788B2 (en) | 2020-03-18 | 2023-10-10 | Hisense Visual Technology Co., Ltd. | Display apparatus and display control method |
| US11825577B2 (en) | 2020-08-24 | 2023-11-21 | Hisense Visual Technology Co., Ltd. | Display apparatus and step power circuit |
| CN115459411A (en) * | 2022-11-10 | 2022-12-09 | 荣耀终端有限公司 | Power supply device and terminal equipment |
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| Publication number | Publication date |
|---|---|
| CN108364613B (en) | 2020-03-06 |
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Address after: 266555 Qingdao economic and Technological Development Zone, Shandong, Hong Kong Road, No. 218 Patentee after: Hisense Visual Technology Co., Ltd. Address before: 266555 Qingdao economic and Technological Development Zone, Shandong, Hong Kong Road, No. 218 Patentee before: QINGDAO HISENSE ELECTRONICS Co.,Ltd. |