CN106211485B - Current control circuit and apply its LED drive circuit - Google Patents
Current control circuit and apply its LED drive circuit Download PDFInfo
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- CN106211485B CN106211485B CN201610795732.3A CN201610795732A CN106211485B CN 106211485 B CN106211485 B CN 106211485B CN 201610795732 A CN201610795732 A CN 201610795732A CN 106211485 B CN106211485 B CN 106211485B
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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]
- H05B45/40—Details of LED load circuits
- H05B45/44—Details of LED load circuits with an active control inside an LED matrix
- H05B45/46—Details of LED load circuits with an active control inside an LED matrix having LEDs disposed in parallel lines
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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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- 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]
- H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
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- Circuit Arrangement For Electric Light Sources In General (AREA)
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Abstract
The invention discloses a kind of current control circuit and apply its LED drive circuit, the present invention is by current control circuit in LED drive circuit, electric current inflow current control circuit in LED load, the electric current for flowing through LED load is adjusted by current control, the current control circuit is integrated in chip, first resistor outside piece is only intended to setting load current, thereon without flow through high current, therefore conventional, electric-resistance can be used, reduce the cost of system, the sampling resistor of the present invention is integrated in piece, even if short circuit occurs for first resistor, current limliting is then carried out by clamp circuit, it is not damage load and adjustment pipe；Meanwhile the present invention can be compatible with a variety of dimmer applications.
Description
Technical field
The present invention relates to power electronics fields, and in particular to a kind of current control circuit and the LED drivings using it
Circuit.
Background technology
LED light since it is than traditional fluorescent lamp and incandescent lamp energy conservation and environmental protection, so LED light slowly replacing it is existing
Fluorescent lamp and incandescent lamp.Linear LED drive circuit realizes advantage simple, at low cost with it, is used widely.
Fig. 1 is the prior art commonly linear LED drive circuit, the grid electricity that amplifier U00 passes through regulating switch pipe M01
Pressure so that sampling resistor R00 on voltage be reference voltage VREF1, by change sampling resistor size come adjust flow through LED bear
Electric current in load, to realize the current constant control on LED.
Since LED load electric current can all flow through sampling resistor R00, the above-mentioned R00 resistance of sampling in the prior art needs
Using power resistor, the cost of drive scheme is increased.In application process, if short circuit, switching tube occur for sampling resistor R00
The grid voltage of M01 can be got higher, and M01 is caused to enter saturation state, cause output current out of control, be easy to happen LED light and opened
Close pipe damage.
In addition, the change of the promotion and application with LED, more and more LED illumination occasions need to meet various light modulation need
It asks, and the linear LED drive circuit of the above-mentioned prior art, it is various to can not achieve PWM light modulations, simulation light modulation, controllable silicon light modulation etc.
The occasion for having light modulation demand limits the application of LED load.
Invention content
In view of this, the purpose of the present invention is to provide one kind load and tune are hardly damaged when short circuit occurs for off chip resistor
The current control circuit of homogeneous tube and its LED drive circuit is applied, and further compatible light modulation needs, and extends using model
It encloses, to solve technical problem of the existing technology.
Technical solution of the invention is to provide a kind of current control circuit with lower structure, including：
Adjustment pipe is connected with the first end of load in series, the adjustment pipe with the load, the sampled resistance of second end
Earthing potential；
Generating circuit from reference voltage, input terminal connection first resistor or connection the first control voltage connect through first resistor
Ground potential；The generating circuit from reference voltage generates reference voltage according to the electric current of its input terminal；Or its input terminal connection the
One resistance or/and the first control voltage ground current potential；The generating circuit from reference voltage generates ginseng according to the voltage of its input terminal
Examine voltage；
First amplifier, output end are connect with the control terminal of the adjustment pipe, and first input end receives the reference
Voltage, the second input terminal receive the current sampling signal that characterization flows through adjustment pipe transient current.
Preferably, the current control circuit is integrated circuit, first end, the generating circuit from reference voltage of pipe are adjusted
Input terminal and sampling resistor three pins of the ground terminal as integrated circuit, the first resistor is as discrete device position
In outside piece.
Preferably, the electric current of described its input terminal of generating circuit from reference voltage is the first electric current, the first electric current is through electricity
Traffic mirroring goes out on the second electric current to resistance element, second electric current on the resistance element generated pressure drop as institute
State reference voltage.
Preferably, the generating circuit from reference voltage includes the second amplifier, the first transistor, current mirror module and the
Two resistance, the first end of second amplifier receive the reference signal of the first current reference value of characterization, and the of second amplifier
Two ends receive the voltage of current control circuit input terminal, and the output end of the second amplifier and the control terminal of the first transistor connect
It connects；The first end of the first transistor is connect with the input terminal of the current mirror module, and the second of the first transistor
End receives the voltage of current control circuit input terminal；The output end of the current mirror module is connect with the second resistance.
Preferably, the generating circuit from reference voltage include the first current source, first current source with it is described
First resistor connection, the first current source in the first resistor produced pressure drop as the reference voltage.
Preferably, the current control circuit further includes clamp circuit, the clamp circuit is to first electricity
The voltage clamping of the voltage at both ends, the voltage at second resistance both ends or the first amplifier output end is hindered to voltage limiting value, to realize limit
Stream.
Preferably, the first resistor is the electricity that variable resistance or variable resistance are formed with fixed resistance connection in series-parallel
Resistance group.
Preferably, the first resistor is connected to dim signal block coupled in series or by the dim signal module
Between the input terminal and ground of generating circuit from reference voltage, the dim signal module is simulation dim signal or PWM light modulation letters
Number, according to the variation of the simulation dim signal or PWM dim signals, change the electric current for flowing through load, to realize light modulation.
Another technical solution of the present invention is to provide a kind of LED drives of the applied current control circuit with lower structure
Dynamic circuit, including LED load and any one of the above current control circuit, the rectified bridge of AC power obtain input voltage to institute
The LED load power supply stated.
The another technical solution of the present invention is to provide a kind of LED drives of the applied current control circuit with lower structure
Dynamic circuit, including LED load, the first current control circuit and the second current control circuit, AC power is successively through thyristor regulating
Light device and rectifier bridge obtain input voltage and power to the LED load, and first current control circuit is negative with the LED
Series connection is carried, first current control circuit is any one of the above current control circuit, second current control electricity
The first end on road is connect through power resistor with the hot end of the input voltage, the low electricity of second end and the input voltage
The connection of position end.
Preferably, when input voltage is more than the pressure drop at LED load both ends, then described in the control of the first current control circuit
LED load electric current be fixed value, when input voltage be less than LED load both ends pressure drop when, the electric current of LED load is zero,
At this point, second current control circuit generates supplemental current, so that input current is not less than the maintenance of controllable silicon dimmer
Electric current.
Preferably, second current control circuit is also a kind of current control circuit of any of the above, the electric current control
First resistor in circuit processed includes two concatenated resistance, the common end of two concatenated resistance and first current control
The ground potential of circuit connects.
Preferably, second current control circuit is also a kind of current control circuit of any of the above, the electric current control
First resistor in circuit processed is connect with the input terminal of generating circuit from reference voltage in the first current control circuit.
Circuit structure using the present invention has the following advantages compared with prior art：The present invention is by current control circuit
In LED drive circuit, electric current inflow current control circuit in LED load flows through LED load by current control adjusting
Electric current, the current control circuit is integrated in chip, and the first resistor outside piece is only intended to setting load current, thereon
Without flow through high current, therefore conventional, electric-resistance can be used, reduce the cost of system, sampling resistor of the invention is integrated in piece
It is interior, even if short circuit occurs for first resistor, then current limliting is carried out by clamp circuit, is not damage load and adjustment pipe；Meanwhile this
Invention can be compatible with a variety of dimmer applications.
Description of the drawings
Fig. 1 is the LED drive circuit schematic diagram of the prior art；
Fig. 2 is the circuit structure diagram of current control circuit embodiment one of the present invention；
Fig. 3 (a) is a kind of electrical block diagram of reference voltage circuit；
Fig. 3 (b) is another electrical block diagram of reference voltage circuit；
Fig. 4 (a) is the circuit structure diagram of current control circuit embodiment two of the present invention；
Fig. 4 (b) is the dimming curve figure when embodiment of the present invention two uses Fig. 3 (a) scheme；
Fig. 4 (c) is the dimming curve figure when embodiment of the present invention two uses Fig. 3 (b) scheme；
Fig. 5 (a) is the circuit structure diagram of current control circuit embodiment three of the present invention；
Fig. 5 (b) is the dimming curve figure when embodiment of the present invention three uses Fig. 3 (a) scheme；
Fig. 5 (c) is the dimming curve figure when embodiment of the present invention three uses Fig. 3 (b) scheme；
Fig. 6 (a) is the circuit structure diagram of current control circuit example IV of the present invention；
Fig. 6 (b) is the dimming curve figure when embodiment of the present invention four uses Fig. 3 (a) scheme；
Fig. 6 (c) is the dimming curve figure when embodiment of the present invention four uses Fig. 3 (b) scheme；
Fig. 7 is a kind of circuit structure diagram of LED drive circuit of the present invention；
Fig. 8 is another circuit structure diagram of LED drive circuit of the present invention；
Fig. 9 (a) Fig. 9 (b) is embodiment input voltage VIN and input under different thyristor operating angles of Fig. 7 of the present invention
The oscillogram of electric current iIN.
Specific implementation mode
The preferred embodiment of the present invention is described in detail below in conjunction with attached drawing, but the present invention is not restricted to these
Embodiment.The present invention covers any replacement made in the spirit and scope of the present invention, modification, equivalent method and scheme.
In order to make the public have thorough understanding to the present invention, it is described in detail in following present invention preferred embodiment specific
Details, and description without these details can also understand the present invention completely for a person skilled in the art.
The present invention is more specifically described by way of example with reference to attached drawing in the following passage.It should be noted that attached drawing is adopted
Use with more simplified form and non-accurate ratio, only to it is convenient, lucidly aid in illustrating the embodiment of the present invention
Purpose.
Refering to what is shown in Fig. 2, illustrating the particular circuit configurations of current control circuit embodiment one of the present invention, and give this
Application of the invention in LED drive circuit.It is loaded by taking LED as an example, and input power is that exchange inputs, the exchange input warp
The input voltage of direct current, the i.e. input voltage as load are exported after rectifier bridge, the rectifier bridge is by diode D01~D04
Composition.Current control circuit in the present embodiment includes adjusting pipe M01, generating circuit from reference voltage U01 and the first amplifier U02,
The adjustment pipe M01 connects with LED load, and the first end of the adjustment pipe M01 is connect with the LED load, second end
Sampled resistance R00 earthing potentials；The input terminal of generating circuit from reference voltage U01 connects first resistor R02 and through first resistor
Earthing potential, although the case where the present embodiment attached drawing only describes connection first resistor R02, generating circuit from reference voltage U01
Input terminal can also be realized by connection the first control voltage, i.e., replaced on first resistor R02 with the first control voltage
Pressure drop, the first control voltage can need to be configured and adjust according to circuit.In the present embodiment, the reference voltage production
Raw circuit U 01 generates reference voltage VREF0, by adjusting first resistor R02's according to the pressure drop on the first resistor R02
Resistance value can adjust the value of reference voltage VREF0.The first of the output end of generating circuit from reference voltage U01 and the first amplifier U02
Input terminal (positive input terminal) connects, and adjustment pipe the second input terminals of M01 (negative input end) receive characterization and flow through adjustment pipe transient current
Current sampling signal, that is, be connected to sampling resistor R00 and adjust the common end of the second end of pipe M01.First amplifier U02's is defeated
Outlet is connect with the control terminal of the adjustment pipe M01.
The adjustment pipe M01 realizes that first end is drain electrode using NMOS, and second end is source electrode, and control terminal is grid
Pole is illustrated with NMOS herein, this can not constitute the limitation that pipe is adjusted using other types.First amplifier U02 passes through control
The grid voltage of system adjustment pipe M01 is so that the voltage on sampling resistor R00 is equal to VREF0, to realize adjusting LED load
Output constant current may be implemented in the case of no light modulation in electric current.
As seen from Figure 2, the current control circuit is integrated circuit, adjusts first end (OUT terminal), the reference of pipe
Three pins of the input terminal (ends EXT) of voltage generation circuit and the ground terminal (ends GND) of sampling resistor as integrated circuit, institute
The first resistor R02 stated is located at as discrete device outside piece.
Since current control circuit is desirably integrated into chip, when it is integrated into a chips, on first resistor R02 simultaneously
Without flow through LED current, be only intended to electric current in setting LED load, it is possible to select conventional, electric-resistance, reduce system schema at
This.And sampling resistor R00 is integrated in piece, is not susceptible to short circuit phenomenon.
With reference to shown in figure 3 (a), the particular circuit configurations of generating circuit from reference voltage U01 are illustrated, i.e., a kind of realization side
Formula.Generating circuit from reference voltage U01 generates fixed voltage at the ends EXT, then the electric current for flowing through first resistor R02 is i01 (as the
One electric current), generating circuit from reference voltage generates reference current Iref, flows through second resistance R01 (as resistance element) and arrives ground,
Iref and the proportional relationships of electric current i01, the reference current Iref (as the second electric current) generate pressure drop in second resistance R01
And VREF0 as the reference voltage.For the concrete structure in this attached drawing, wherein the generating circuit from reference voltage according to
Pressure drop on the first resistor R02 generates the first electric current i01, the first electric current i01 and goes out the second electricity through current mirror mirror image
Flow Iref to resistance element R01 on, the second electric current Iref on the resistance element R01 generated pressure drop as institute
State reference voltage VREF0.
Further, the generating circuit from reference voltage includes the second amplifier U05, the first transistor M05, current mirror mould
The first end (positive input terminal) of block and second resistance R01, the second amplifier U05 receive the first current reference value of characterization and (also may be used
Be considered characterize first resistor pressure drop reference value) reference signal Vref, the second end (negative input of the second amplifier U05
End) pressure drop on first resistor R02 is received, the output end of the second amplifier U05 and the control terminal of the first transistor M05 connect
It connects；The first end of the first transistor M05 is connect with the input terminal of the current mirror module, the first transistor M05
Second end connection first resistor and through first resistor earthing potential；The output end of the current mirror module and described second
Resistance R01 connections.The current mirror module is made of two PMOS M06 and M07.
For the first transistor M05 by taking NMOS as an example, control terminal is grid, and first end is drain electrode, and second end is source electrode.
Second amplifier U05 is reference voltage Vref to control the voltage on resistance R02 by the grid of control the first transistor M05,
PMOS M06 and M07 forms current mirror so that the proportional relationship of electric current of electric current Iref and M06 on M07, i.e. electric current on M07
With the proportional relationship of electric current on resistance R02.If M06 and M07 are PMOS, breadth length ratio respectively (W/L) and k1 (W/L),
Then M07 electric currents and M06 current ratios are k1 (k1 is any number), then it is k1* (R01/R00) * to flow through LED load size of current
Vref/R02。
It is in parallel that clamp circuit U03, clamp circuit U03 and second resistance R01 are further illustrated in Fig. 3 (a).Since there are clampers
Circuit U 03, even if short circuit occurs for the first resistor R02 for setting electric current, output current can also be controlled in VCLAMP/
R00, wherein VCLAMP is the clamp voltage of clamp circuit.When current control circuit is integrated into a chips, current sample electricity
Resistance R00 is integrated in chip interior, avoids sampling resistor short circuit in traditional scheme, causes output current is excessive system is caused to damage
It is bad.
The way of LED current current limliting be not limited only to it is above-mentioned described that clamp circuit U03 and resistance R01 is in parallel, can also
Current limliting is carried out in generating circuit from reference voltage U01, to ensure that voltage is not above certain value on R01；It can also be first
The output end of amplifier U02 carries out voltage clamping, to limit LED current.
With reference to shown in figure 3 (b), the particular circuit configurations of generating circuit from reference voltage U01 are illustrated, i.e., another realization side
Formula.In this attached drawing, the generating circuit from reference voltage U01 include the first current source I15, the first current source I15 with
The first resistor R02 connections, the first current source I15 on the first resistor R02 produced pressure drop as the ginseng
Examine voltage VREF0.Based on integrated circuit, then the internal current source I15 of generating circuit from reference voltage U01 is in the generation fixation of the ends EXT
Electric current, then the voltage on first resistor R02 is VREF0.Setting for clamp circuit U03, then can be by clamp circuit U03 and electricity
It is in parallel to hinder R02, the voltage of clamper VREF0.When VREF0 is to reach clamp voltage, VREF0=I15*R02, then LED current is big
Small is I15*R02/R00, to carry out current limliting to load.
With reference to shown in figure 4 (a), the circuit structure principle of current control circuit embodiment two of the present invention is illustrated, with implementation
It is improved on the basis of example one, that is, increases the function of light modulation.First resistor R02 setting electric currents are utilized in the present embodiment
Characteristic, that is, load current can be changed by changing first resistor R02, to realize light modulation, therefore first resistor R02 is arranged to can be changed
Resistance or variable resistance group, for example, adjustable resistance R02 can also be in series or in parallel with a fixed resistance and an adjustable resistance
Mode is realized.
When generating circuit from reference voltage U01 uses the scheme of Fig. 3 (a), LED current size is k1* as previously described
(R01/R00) * Vref/R02, i.e. resistance R02 is bigger, and output current is smaller；Resistance R02 is smaller, and output current is bigger.Pass through pincers
Position circuit limits maximum output current, shown in dimming curve such as Fig. 4 (b)；When generating circuit from reference voltage U01 uses Fig. 3 (b)
Scheme when, LED current size as previously described be I15*R02/R00, i.e. resistance R02 is bigger, and output current is bigger；Resistance
R02 is smaller, and output current is smaller.Maximum output current is limited by clamp circuit, shown in dimming curve such as Fig. 4 (c).
With reference to shown in figure 5 (a), the circuit structure principle of current control circuit embodiment three of the present invention is illustrated, with implementation
The function of simulation light modulation is increased on the basis of example one, i.e., uses variable resistance light modulation different with embodiment two.Institute
The first resistor R02 stated and dim signal block coupled in series, the dim signal module is simulation light modulation letter in the present embodiment
Number U11 changes the electric current for flowing through LED load according to the simulation dim signal U11, to realize light modulation.When simulation dim signal
When U11 and resistance R02 connect, simulation dim signal U11 can be with R02 transpositions.
By taking the specific connection relation in Fig. 5 (a) as an example, when generating circuit from reference voltage uses the scheme in Fig. 3 (a),
The dimmer voltage of characterization simulation dim signal is higher, then the electric current of LED is smaller；Analog voltage is lower, and LED current is bigger.Work as table
When the dimmer voltage of sign simulation dim signal is 0, LED current size is identical with size when being added without simulation dim signal, when
When the dimmer voltage of characterization simulation dim signal reaches the reference voltage Vref in generating circuit from reference voltage, then output current is
0.Shown in dimming curve such as Fig. 5 (b), wherein i is the LED current size simulated when dim signal is 0.When reference voltage generates electricity
When road uses the scheme in Fig. 3 (b), if the voltage of simulation dim signal is higher, then the electric current of LED is bigger；Analog voltage is lower,
LED current is smaller.Shown in dimming curve such as Fig. 5 (c), wherein i is the LED current size simulated when dim signal is 0.Work as simulation
When voltage is 0, LED current size is identical with size when being added without simulation dim signal.When resistance R02 be 0, i.e., only simulate
When dim signal is connected between the ends EXT and ground, LED current can be to 0.
With reference to shown in figure 6 (a), the circuit structure principle of current control circuit example IV of the present invention is illustrated, with implementation
The function of PWM light modulations is increased on the basis of example one, i.e., is had using variable resistance and simulation light modulation with embodiment two and three
Institute is different.PWM dim signals U10 and R02 are connected, is connected between the ends EXT of current control circuit and ground and can be realized.Its
In, PWM voltage dim signals U10 can be with R02 transpositions.Can also PWM dim signals U10 be directly connected to the ends EXT
Between ground.
The present embodiment is when using generating circuit from reference voltage shown in Fig. 3 (a), when pwm signal is high, the wink of LED
When electric current be 0；When pwm signal is low, the transient current of LED is maximum value, i.e., the value not dimmed.Wherein, the height of pwm signal
Level needs to be higher than reference voltage Vref, and the low level of pwm signal is 0.Then the average current of LED is i* (1-D).Wherein, i is
LED current when non-dimmable, D are the percentage that pwm signal high level accounts for switch periods.Shown in dimming curve such as Fig. 6 (b).When
Using when generating circuit from reference voltage, when pwm signal is high, the transient current of LED is maximum value shown in Fig. 3 (b)；When
When pwm signal is low, the transient current of LED is the value not dimmed.Wherein, the low level of pwm signal is 0, then the average electricity of LED
Stream is i+ (V3/R00) * D.Wherein, LED current when i is non-dimmable, V3 are the value of PWM dim signal high level, wherein
I15*R02+V3 is less than clamped voltage value.When I15*R02+V3 is more than or equal to clamped voltage value, then LED average currents size is
VCLAMP*D/R00+i(1-D).Shown in dimming curve such as Fig. 6 (c).
Refering to what is shown in Fig. 7, illustrating the particular circuit configurations of the LED drive circuit of the present invention.The rectified bridge of AC power
Input voltage VIN is obtained to load supplying, C01 is input capacitance.The LED drive circuit includes LED load, the first electric current
Control circuit U15 and the second current control circuit U16, AC power obtain input electricity through controllable silicon dimmer and rectifier bridge successively
VIN is pressed to power the LED load, first current control circuit is connected with the LED load, the described first electricity
Flow control circuit U15 is any one of the above current control circuit, and the first end of the second current control circuit U16 is through work(
Rate resistance R12 is connect with the hot end of the input voltage VIN, the cold end of second end and the input voltage VIN
Connection.
When the pressure drop that input voltage VIN is more than LED load both ends adds the cut-in voltage of the first current control circuit U15
(the first current control circuit U15 cut-in voltages, which refer to minimum voltage between OUT and GND, can ensure that the first current control circuit can
With normal work), then the electric current of the first current control circuit U15 controls LED loads is fixed value, works as input voltage
When the pressure drop that VIN is less than LED load both ends adds the cut-in voltage of the first current control circuit U15, the electric current of LED load is
Zero, at this point, the second current control circuit U16 generates supplemental current, so that input current is not less than controllable silicon dimmer
Maintenance electric current.
The second current control circuit U16 is also a kind of current control circuit of any of the above, the current control circuit
In first resistor include two concatenated resistance, i.e. R11 and R10, the common end of two concatenated resistance with it is described first electricity
The ground potential of flow control circuit U15 connects.
It is described as follows based on 7 concrete structure of attached drawing：The positive output end of input rectifying bridge is connected to the one of power resistor R12
End, the other end of power resistor R12 are connected to the OUT terminal of current control circuit U16, and the ground of current control circuit U16 is connected to
The negative output terminal of input rectifying bridge.The ends EXT of current control circuit U16 are connected to electricity by two concatenated resistance R10 and R11
The ground of flow control circuit U16.The positive input terminal of rectifier bridge is also connected to the anode of LED load, and the negative terminal of LED load is connected to electricity
The OUT terminal of flow control circuit U15, resistance R02 are connected between the ends EXT of current control circuit U15 and GND, current control electricity
The ground of road U15 is connected to the common end of resistance R10 and resistance R11.
The output current of first resistor R02 settings LED, when input voltage VIN is more than LED voltage VLED, then electric current control
It is I2 that circuit U 15 processed is arranged resistance R02 to control LED current size by output current；When input voltage VIN is less than LED voltage
When VLED, then electric current is 0 on LED.When input voltage is less than LED voltage, LED current 0, then needs addition in input is certain
Maintenance electric current so that it is silicon-controlled to be always maintained at conducting, prevent shutdown cause to flicker.When LED has electric current, then LED current stream
Resistance R11 is crossed, a constant pressure drop is generated on resistance R11.Since the electric current of the ends EXT outflow is much smaller than LED current, calculating
When the electric current of R12, the size of current that can be approximately considered power resistor R12 is：K*(Vref-iLED*R11)/R10；Wherein K is
Coefficient in current control circuit, as the circuit using Fig. 3 (a), and M06:M07=1:1, then K=(R01/R00).Therefore
LED current is bigger, then the electric current on power resistor R12 is smaller, when iLED*R11 is more than or equal to Vref, then power resistor R12
On electric current be 0.When LED current is 0, since resistance R11 is much smaller than resistance R10, size of current is on power resistor
K*Vref/R10=I1.In different controlled silicon conducting angles, input voltage VIN and input current iIN waveforms such as Fig. 9 (a) and 9
(b) shown in.By the way that current control circuit U16 and peripheral circuit is added so that when input voltage is less than LED voltage, input electricity
Stream can reach silicon-controlled maintenance electric current, prevent silicon-controlled shutdown from LED light being caused to flicker.And the maintenance size of current
It can be arranged by resistance, circuit is simple, and circuit cost is low.
Refering to what is shown in Fig. 8, illustrating another particular circuit configurations of the LED drive circuit of the present invention.Work as input voltage
VIN is more than cut-in voltage (the first current control circuit U15 of the pressure drop plus the first current control circuit U15 at LED load both ends
Cut-in voltage, which refers to minimum voltage between OUT and GND, can ensure that the first current control circuit can work normally), then first is electric
The electric current of the flow control circuit U15 controls LED load is fixed value, while the EXT of the second current control circuit U16 is higher than
Internal reference voltage, no electric current flow through R13, and also no electric current flows through R12；When input voltage VIN is less than LED load both ends
When pressure drop adds the cut-in voltage of the first current control circuit U15, the input terminal EXT output electricity of the first current control circuit U15
Stream starts to reduce, while the input terminal EXT of the second current control circuit U16 has electric current to flow through R13, at this point, second electricity
Flow control circuit U16 generates supplemental current and flows through R12, so that input current is not less than the maintenance electric current of controllable silicon dimmer.The
The compensation electric current of two current control circuit U16 is determined by resistance R13 and R02.When the ends EXT of the first current control U15 export electricity
When stream is zero, the compensation electric current of the second current control circuit U16 reaches maximum value.
In addition to this, although embodiment is separately illustrated and is illustrated above, it is related to the common technology in part, in this field
Those of ordinary skill apparently, can be replaced and integrate between the embodiments, be related to one of embodiment and record is not known
Content, then can refer to another embodiment on the books.It is related to the part of resistance, resistance group can also be understood as, i.e.,
It is composed in parallel by multiple resistance strings, for example, first resistor can be understood as resistance R11 and R12 series connection.
Embodiments described above does not constitute the restriction to the technical solution protection domain.It is any in above-mentioned implementation
Modifications, equivalent substitutions and improvements etc., should be included in the protection model of the technical solution made by within the spirit and principle of mode
Within enclosing.
Claims (12)
1. a kind of current control circuit, it is characterised in that：Including：
Adjustment pipe is connected with the first end of load in series, the adjustment pipe with the load, the sampled resistance eutral grounding of second end
Current potential；
Generating circuit from reference voltage, input terminal connects first resistor or the first control voltage of connection is grounded by first resistor
Current potential；The generating circuit from reference voltage generates reference voltage according to the electric current of its input terminal；Or its input terminal connection first
Resistance or/and the first control voltage ground current potential；The generating circuit from reference voltage generates reference according to the voltage of its input terminal
Voltage；
First amplifier, output end are connect with the control terminal of the adjustment pipe, and first input end receives the reference voltage,
Its second input terminal receives the current sampling signal that characterization flows through adjustment pipe transient current；
The current control circuit is integrated circuit, adjusts the first end of pipe, the input terminal of generating circuit from reference voltage and adopts
Three pins of the ground terminal of sample resistance as integrated circuit, the first resistor are located at as discrete device outside piece.
2. current control circuit according to claim 1, it is characterised in that：Its input of the generating circuit from reference voltage
The electric current at end is the first electric current, and the first electric current goes out through current mirror on the second electric current to resistance element, and second electric current exists
Generated pressure drop is as the reference voltage on the resistance element.
3. current control circuit according to claim 2, it is characterised in that：The generating circuit from reference voltage includes the
The first end of two amplifiers, the first transistor, current mirror module and second resistance, second amplifier receives characterization the first electric current ginseng
Examine the reference signal of value, the second end of second amplifier receives the voltage of current control circuit input terminal, the second amplifier it is defeated
Outlet is connect with the control terminal of the first transistor；The first end of the first transistor and the current mirror module
Input terminal connects, and the second end of the first transistor receives the voltage of current control circuit input terminal；The current mirror mould
The output end of block is connect with the second resistance.
4. current control circuit according to claim 1, it is characterised in that：The generating circuit from reference voltage includes the
One current source, first current source are connect with the first resistor, and the first current source is produced in the first resistor
Raw pressure drop is as the reference voltage.
5. according to the current control circuit described in any one of claim 1-4, it is characterised in that：The current control electricity
Road further includes clamp circuit, the clamp circuit to the voltage at the first resistor both ends, the voltage at second resistance both ends or
The voltage clamping of first amplifier output end is to voltage limiting value, to realize current limliting.
6. according to the current control circuit described in any one of claim 1-4, it is characterised in that：The first resistor is
The resistance group that variable resistance or variable resistance are formed with fixed resistance connection in series-parallel.
7. according to the current control circuit described in any one of claim 1-4, it is characterised in that：The first resistor with
The dim signal module is connected between the input terminal of generating circuit from reference voltage and ground by dim signal block coupled in series,
The dim signal module is simulation dim signal or PWM dim signals, according to the simulation dim signal or PWM light modulation letters
Number variation, change and flow through the electric current of load, to realize light modulation.
8. a kind of LED drive circuit of applied current control circuit, it is characterised in that：Including LED load and the claims
Any one current control circuit in 1-7, the rectified bridge of AC power obtain input voltage and power to the LED load.
9. a kind of LED drive circuit of applied current control circuit, it is characterised in that：Including LED load, the first current control electricity
Road and the second current control circuit, AC power obtain input voltage to described through controllable silicon dimmer and rectifier bridge successively
LED load is powered, and first current control circuit is connected with the LED load, and first current control circuit is
Any one current control circuit of the claims 1-7, the first end of second current control circuit is through power resistor
It is connect with the hot end of the input voltage, second end is connect with the cold end of the input voltage.
10. the LED drive circuit of applied current control circuit according to claim 9, it is characterised in that：Work as input voltage
More than LED load both ends pressure drop when, then the electric current of the first current control circuit control LED load is fixed value, when
When input voltage is less than the pressure drop at LED load both ends, the electric current of LED load is zero, at this point, second current control circuit
Supplemental current is generated, so that input current is not less than the maintenance electric current of controllable silicon dimmer.
11. the LED drive circuit of applied current control circuit according to claim 10, it is characterised in that：It is negative including LED
It carries, the first current control circuit and the second current control circuit, AC power are obtained through controllable silicon dimmer and rectifier bridge successively
Input voltage powers to the LED load, and first current control circuit is connected with the LED load, and described the
One current control circuit is any one current control circuit of the claims 1-7, second current control circuit
First end is connect through power resistor with the hot end of the input voltage, the cold end of second end and the input voltage
Connection, when input voltage is more than the pressure drop at LED load both ends, then the first current control circuit controls the LED load
Electric current is fixed value, and when input voltage is less than the pressure drop at LED load both ends, the electric current of LED load is zero, at this point, described
Second current control circuit generates supplemental current, so that input current is not less than the maintenance electric current of controllable silicon dimmer, it is described
Second current control circuit is also above any one current control circuit of claim 1-7, the in the current control circuit
One resistance includes two concatenated resistance, the ground potential of the common end of two concatenated resistance and first current control circuit
Connection.
12. the LED drive circuit of applied current control circuit according to claim 10, it is characterised in that：It is negative including LED
It carries, the first current control circuit and the second current control circuit, AC power are obtained through controllable silicon dimmer and rectifier bridge successively
Input voltage powers to the LED load, and first current control circuit is connected with the LED load, and described the
One current control circuit is any one current control circuit of the claims 1-7, second current control circuit
First end is connect through power resistor with the hot end of the input voltage, the cold end of second end and the input voltage
Connection, when input voltage is more than the pressure drop at LED load both ends, then the first current control circuit controls the LED load
Electric current is fixed value, and when input voltage is less than the pressure drop at LED load both ends, the electric current of LED load is zero, at this point, described
Second current control circuit generates supplemental current, so that input current is not less than the maintenance electric current of controllable silicon dimmer, it is described
Second current control circuit is also above any one current control circuit of claim 1-7, the in the current control circuit
One resistance is connect with the input terminal of generating circuit from reference voltage in the first current control circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610795732.3A CN106211485B (en) | 2016-08-31 | 2016-08-31 | Current control circuit and apply its LED drive circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201610795732.3A CN106211485B (en) | 2016-08-31 | 2016-08-31 | Current control circuit and apply its LED drive circuit |
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| CN106211485A CN106211485A (en) | 2016-12-07 |
| CN106211485B true CN106211485B (en) | 2018-09-21 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107548206A (en) * | 2017-09-15 | 2018-01-05 | 佛山市华全电气照明有限公司 | By identifying that LED Vf values adjust the driving power circuit of output voltage |
| CN108430139B (en) | 2018-05-28 | 2020-03-06 | 矽力杰半导体技术(杭州)有限公司 | LED driving circuit with silicon controlled rectifier dimmer and control method thereof |
| CN110324935B (en) * | 2019-06-19 | 2024-05-24 | 杰华特微电子（张家港）有限公司 | Efficient linear LED driving circuit and method |
| CN114495844A (en) * | 2022-01-26 | 2022-05-13 | 北京奕斯伟计算技术有限公司 | Dimming circuit, backlight control system and display device of LED |
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| CN103179743A (en) * | 2009-03-04 | 2013-06-26 | 立锜科技股份有限公司 | Led driver with direct ac-dc conversion and control, and method and integrated circuit therefor |
| US8427073B2 (en) * | 2009-05-27 | 2013-04-23 | Green Solution Technology Co., Ltd. | LED driving circuit and backlight module |
| JP5720392B2 (en) * | 2011-04-14 | 2015-05-20 | 日亜化学工業株式会社 | Light emitting diode drive device |
| CN202652627U (en) * | 2012-05-30 | 2013-01-02 | 许瑞清 | Linear constant current controller |
| CN202889703U (en) * | 2012-08-23 | 2013-04-17 | 冠捷显示科技（厦门）有限公司 | DC light-modulation type LED drive circuit |
| CN205265954U (en) * | 2015-12-21 | 2016-05-25 | 无锡中感微电子股份有限公司 | Acoustic control LED circuit |
| CN105792441B (en) * | 2016-04-29 | 2018-02-23 | 苏州智浦芯联电子科技股份有限公司 | A kind of linear constant current circuit for controllable silicon light modulation |
| CN206042450U (en) * | 2016-08-31 | 2017-03-22 | 杰华特微电子（杭州）有限公司 | Current control circuit and use its LED drive circuit |
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Address after: Room 901-23, 9 / F, west 4 building, Xigang development center, 298 Zhenhua Road, Sandun Town, Xihu District, Hangzhou City, Zhejiang Province, 310030 Patentee after: Jiehuate Microelectronics Co.,Ltd. Address before: Room 424, building 1, 1500 Wenyi West Road, Cangqian street, Yuhang District, Hangzhou City, Zhejiang Province Patentee before: JOULWATT TECHNOLOGY (HANGZHOU) Co.,Ltd. |
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