CN111200892B - LED control device, circuit and control method thereof - Google Patents
LED control device, circuit and control method thereof Download PDFInfo
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- CN111200892B CN111200892B CN202010128530.XA CN202010128530A CN111200892B CN 111200892 B CN111200892 B CN 111200892B CN 202010128530 A CN202010128530 A CN 202010128530A CN 111200892 B CN111200892 B CN 111200892B
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Abstract
The invention discloses an LED control device, a circuit and a control method thereof, wherein the LED control circuit comprises a control module, at least one LED lamp string and constant current source modules corresponding to the number of the LED lamp strings; the control module is used for outputting dimming voltage to the constant current source module according to an externally input dimming signal; the constant current source module is used for adjusting the working current of the LED lamp string according to the dimming voltage; the control module is further used for comparing the voltage value of the dimming signal with at least one preset comparison voltage, selecting a corresponding power supply voltage according to a comparison result, outputting the power supply voltage to the constant current source module, controlling the difference value between the power supply voltage and the output voltage of the constant current source module, and further avoiding the luminous flickering of the LED lamp string when the brightness is reduced and the conduction radiation caused by the abrupt change of the working current.
Description
Technical Field
The invention relates to the technical field of LEDs, in particular to an LED control device, an LED circuit and an LED control method.
Background
In LED dimming applications, a constant current circuit is generally used to control the current of an LED string to emit light, and the constant current circuit is composed of an operational amplifier and an N-type MOS tube, and the current flowing through the LED string can be controlled by adjusting the voltage of the non-inverting input terminal of the operational amplifier, so as to realize dimming applications.
As shown in fig. 1, when the line voltage is smaller than the LED string voltage, the inverting input terminal of the operational amplifier is grounded through the sampling resistor, the output voltage of the operational amplifier is VDD0, the MOS transistor Q is turned on, when the line voltage increases and is larger than the sum of the LED string voltage and the Vds voltage of the MOS transistor, the LED string starts to have a current flowing therethrough, the inverting input terminal voltage of the operational amplifier is equal to Rcs0×iled0, iled0 is the LED string current, and when the dimming voltage is unchanged, a response time is required for the inverting input terminal voltage of the operational amplifier to change to the output terminal voltage stability, and in the response time, the output terminal voltage of the operational amplifier is reduced from VDD0 to Vs0, vs0 is the output voltage of the operational amplifier corresponding to the dimming voltage, and the LED string current is also reduced from the LED string current corresponding to the VDD0 to the LED string current set to the dimming voltage, that is, the dimming voltage/Rcs 0. During the period that the voltage at the output end of the operational amplifier changes from VDD0 to Vs0, the time is determined by the response time of the operational amplifier, the LED string current generates abrupt change, and the magnitude of the abrupt change current is determined by the difference value of VDD0-Vs 0. When the dimming voltage is regulated to be smaller by the controller, the voltage Vs0 output when the operational amplifier is stable is smaller, the difference value between VDD0 and Vs0 is larger, the current mutation of the LED lamp string is larger, a series of problems such as low power factor, poor harmonic wave and conductive radiation are caused, and even when the brightness of the LED lamp string is regulated to a certain degree, the current mutation causes the LED lamp string to emit light and flash.
There is thus a need for improvements and improvements in the art.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide an LED control device, a circuit and a control method thereof, which can effectively avoid the flickering of the LED string light when the brightness is reduced and the conduction radiation caused by the abrupt change of the operating current.
In order to achieve the above purpose, the invention adopts the following technical scheme:
an LED control circuit comprises a control module, at least one LED lamp string and constant current source modules, wherein the number of the constant current source modules corresponds to that of the LED lamp strings; the control module is used for outputting dimming voltage to the constant current source module according to an externally input dimming signal; the constant current source module is used for adjusting the working current of the LED lamp string according to the dimming voltage; the control module is further used for comparing the voltage value of the dimming signal with at least one preset comparison voltage, selecting a corresponding power supply voltage according to the comparison result, outputting the power supply voltage to the constant current source module, and controlling the difference value between the power supply voltage and the output voltage of the constant current source module.
In the LED control circuit, the control module is specifically configured to compare a voltage value of the dimming signal with a first preset comparison voltage and a second preset comparison voltage, and output a first supply voltage to the constant current source module when the voltage value of the dimming signal is smaller than the first preset comparison voltage; outputting a second power supply voltage to the constant current source module when the voltage value of the dimming signal is larger than the first preset comparison voltage and smaller than the second preset voltage; outputting a third power supply voltage to the constant current source module when the voltage value of the dimming signal is larger than the second preset voltage; the first preset comparison voltage is smaller than the second preset comparison voltage.
In the LED control circuit, the control module comprises a comparison unit, a control unit and a voltage output unit; the voltage output unit is used for outputting the power supply voltage to the constant current source module according to a reference voltage; the comparison unit is used for comparing the voltage value of the dimming signal with the first preset voltage and the second preset voltage and outputting a corresponding level signal to the control unit according to a comparison result; and the control unit controls the voltage output unit to output corresponding power supply voltage to the constant current source module according to the level signal.
In the LED control circuit, the comparison unit comprises a first comparator and a second comparator; the non-inverting input end of the first comparator is connected with the dimming signal input end, the inverting input end of the first comparator is connected with a first preset comparison voltage input end, and the output end of the first comparator is connected with the control unit; the positive phase input end of the second comparator is connected with the dimming signal input end, the negative phase input end of the second comparator is connected with the second preset comparison voltage input end, and the output end of the second comparator is connected with the control unit.
In the LED control circuit, the control unit comprises a first switch, a second resistor and a third resistor; one end of the first switch is connected with the voltage output unit and one end of the first resistor, the other end of the first switch and the other end of the first resistor are connected with one end of the second switch and one end of the second resistor, and the other end of the second resistor and the other end of the second switch are connected with the voltage output unit; the control end of the first switch and the control end of the second switch are both connected with the comparison unit.
In the LED control circuit, the voltage output unit comprises a first operational amplifier, a first MOS tube, a third resistor and a fourth resistor; the positive input end of the first operational amplifier is connected with a reference voltage input end, the negative input end of the first operational amplifier is connected with the control unit and one end of the fourth resistor, the output end of the first operational amplifier is connected with the grid electrode of the first MOS tube, the source electrode of the first MOS tube is connected with the other end of the fourth resistor and the constant current source module, and the drain electrode of the first MOS tube is connected with the voltage input end; one end of the third resistor is connected with the control unit, and the other end of the third resistor is grounded.
In the LED control circuit, the control module further includes a filtering unit, where the filtering unit is configured to perform filtering processing on the dimming signal and output the filtered dimming signal to the comparing unit.
In the LED control circuit, the filtering unit comprises a capacitor and a fifth resistor; one end of the capacitor is connected with one end of the fifth resistor and the comparison unit, and the other end of the capacitor is grounded; the other end of the fifth resistor is connected with the dimming signal input end.
A control method based on the LED control circuit described above, comprising the steps of:
the control module outputs dimming voltage to the constant current source module according to an externally input dimming signal;
the constant current source module adjusts the working current of the LED lamp string according to the dimming voltage;
the control module is used for comparing the voltage value of the dimming signal with at least one preset comparison voltage, outputting a corresponding power supply voltage to the constant current source module according to the comparison result, and controlling the difference value between the power supply voltage and the output voltage of the constant current source module.
The LED control device comprises a shell, wherein a PCB is arranged in the shell, and the LED control device is characterized in that the LED control circuit is arranged on the PCB.
Compared with the prior art, the LED control device, the circuit and the control method thereof provided by the invention have the advantages that the LED control circuit comprises a control module, at least one LED lamp string and constant current source modules corresponding to the LED lamp strings in number; the control module is used for outputting dimming voltage to the constant current source module according to an externally input dimming signal; the constant current source module is used for adjusting the working current of the LED lamp string according to the dimming voltage; the control module is further used for comparing the voltage value of the dimming signal with at least one preset comparison voltage, selecting a corresponding power supply voltage according to a comparison result, outputting the power supply voltage to the constant current source module, controlling the difference value between the power supply voltage and the output voltage of the constant current source module, and further avoiding the luminous flickering of the LED lamp string when the brightness is reduced and the conduction radiation caused by the abrupt change of the working current.
Drawings
FIG. 1 is a schematic circuit diagram of a conventional LED control circuit;
fig. 2 is a block diagram of an LED control circuit according to the present invention;
FIG. 3 is a schematic circuit diagram of a first embodiment of an LED control circuit according to the present invention;
FIG. 4 is a schematic circuit diagram of a second embodiment of an LED control circuit according to the present invention;
fig. 5 and fig. 6 are schematic circuit diagrams of a constant current source module and an LED string in the LED control circuit provided by the present invention;
fig. 7 is a flowchart of steps of a control method of an LED control circuit provided by the present invention.
Detailed Description
The LED control device, the circuit and the control method thereof can effectively avoid the luminous flicker of the LED lamp string when the brightness is reduced and the conduction radiation caused by the abrupt change of the working current.
In order to make the objects, technical solutions and effects of the present invention clearer and more specific, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Referring to fig. 2, the LED control circuit provided by the present invention includes a rectifying module 100, a control module 200, at least one LED string 300, and constant current source modules 400 corresponding to the number of LED strings 300; when the number of the LED light strings 300 is one or more, the LED light strings 300 are connected in series, and the positive electrode of the LED light string 300 obtained after the series connection is connected with the rectifying module 100 and the negative electrode thereof is connected with the constant current source module 400; when the LED string 300 is one, the positive electrode of the LED string 300 is connected to the rectifying module 100, and the negative electrode of the LED string 300 is connected to the constant current source module 400; the rectification module 100 is further connected to an ac input terminal and the control module 200, and the control module 200 is further connected to the constant current source module 400.
The rectifying module 100 converts an input alternating current into a line voltage and outputs the line voltage to the LED string 300 and the control module 200, and provides electric energy for the control module 200 and the LED string 300; the control module 200 is configured to output a dimming voltage to the constant current source module 400 according to an externally input dimming signal; the constant current source module 400 is configured to adjust the working current of the LED string 300 according to the dimming voltage; the control module 200 is further configured to compare the voltage value of the dimming signal with at least one preset comparison voltage, and select a corresponding power supply voltage VDD according to the comparison result, and output the power supply voltage VDD to the constant current source module 400, to control a difference between the power supply voltage VDD and an output voltage of the constant current source module 400, and specifically, to control to reduce the difference between the power supply voltage VDD and the output voltage of the constant current source module 400; according to the invention, the control module 200 controls the power supply voltage VDD to change along with the voltage value of the dimming signal, so that the difference between the power supply voltage VDD and the output voltage of the constant current source module 400 is reduced, the abrupt change of the working current of the LED lamp string 300 is reduced, the light-emitting flickering of the LED lamp string 300 when the brightness is reduced is improved, the power factor is increased, and the harmonic value is reduced.
Further, the present invention specifically describes the working process in the LED control circuit by setting two comparison preset voltages, and in other embodiments, the number of comparison voltages may be set according to the needs, which is not limited by the present invention.
The control module 200 is specifically configured to compare the voltage value of the dimming signal with a first preset comparison voltage Vref1 and a second preset comparison voltage Vref2, where the first preset comparison voltage Vref1 is smaller than the second preset comparison voltage Vref2, and output a first supply voltage to the constant current source module 400 when the voltage value of the dimming signal is smaller than the first preset comparison voltage Vref 1; when the voltage value of the dimming signal is greater than the first preset comparison voltage Vref1 and smaller than the second preset voltage, outputting a second power supply voltage to the constant current source module 400; when the voltage value of the dimming signal is greater than the second preset voltage, outputting a third power supply voltage to the constant current source module 400, dividing the voltage value of the dimming signal into three parts by setting two comparison voltages, namely outputting a corresponding power supply voltage VDD according to the voltage value of the dimming signal, so that the power supply voltage VDD is changed according to the change of the dimming signal, and further reducing the difference between the power supply voltage VDD and the output voltage of the constant current source module 400 to reduce the abrupt change of the working current of the LED lamp string 300; when more comparison voltages are set, the voltage value of the dimming signal is divided more finely, and the corresponding difference value between the power supply voltage VDD and the output voltage is smaller, so that the power factor is further improved, and the harmonic wave is reduced.
In specific implementation, referring to fig. 3, in the first embodiment of the present invention, the control module 200 includes a comparing unit 210, a control unit 220, and a voltage output unit 230, where the comparing unit 210 is connected to the dimming signal input end and the control unit 220, the control unit 220 is further connected to the voltage output unit 230, and the voltage output unit 230 is further connected to the constant current source module 400 and the rectifying module 100.
The voltage output unit 230 is configured to output the power supply voltage VDD to the constant current source module 400 according to a reference voltage; the comparing unit 210 is configured to compare the voltage value of the dimming signal with the first preset voltage and the second preset voltage, and output a corresponding level signal to the control unit 220 according to the comparison result; the control unit 220 controls the voltage output unit 230 to output the corresponding power supply voltage VDD to the constant current source module 400 according to the level signal; the comparing unit 210 compares that when the voltage value of the dimming signal is smaller than the first preset comparison voltage Vref1, two low level signals are output to the control unit 220, and the control unit 220 controls the voltage output unit 230 to output a first supply voltage to the constant current source module 400; when the voltage value of the dimming signal is greater than the first preset comparison voltage Vref1 and less than the second preset voltage, a low level signal and a high level signal are output to the control unit 220, and the corresponding voltage output unit 230 outputs a second supply voltage to the constant current source module 400; when the voltage value of the dimming signal is greater than the second preset voltage, two high-level signals are output to the control unit 220, and the corresponding voltage output unit 230 outputs a third power supply voltage to the constant current source module 400, so that different power supply voltages VDD are output according to the voltage value of the dimming signal.
Further, the comparing unit 210 includes a first comparator COMP1 and a second comparator COMP2; the non-inverting input end of the first comparator COMP1 is connected with the dimming signal input end, the inverting input end of the first comparator COMP1 is connected with the input end of a first preset comparison voltage Vref1, and the output end of the first comparator COMP1 is connected with the control unit 220; the positive input end of the second comparator COMP2 is connected to the dimming signal input end, the negative input end of the second comparator COMP2 is connected to the second preset comparison voltage Vref2 input end, the output end of the second comparator COMP2 is connected to the control unit 220, in this embodiment, an analog voltage dimming signal is used as the dimming signal, the first comparator COMP1 directly compares the input dimming signal with the first preset comparison voltage Vref1, the second comparator COMP2 compares the dimming signal with the second preset comparison voltage Vref2, when the voltage value of the dimming signal is smaller than the first preset comparison voltage Vref1, the first comparator COMP1 and the second comparator COMP2 both output a low level, when the voltage value of the dimming signal is larger than the first preset comparison voltage Vref1 and smaller than the second preset voltage, the first comparator COMP1 outputs a high level signal, and when the second comparator COMP2 outputs a high level signal, and when the voltage value of the second comparator COMP2 is larger than the second preset voltage, and the second comparator COMP2 outputs a high level signal, and the control unit further realizes the dimming signal.
Further, with continued reference to fig. 3, the control unit 220 includes a first switch K1, a second switch K2, a second resistor R2, and a third resistor R3; one end of the first switch K1 is connected to the voltage output unit 230 and one end of the first resistor R1, the other end of the first switch K1 and the other end of the first resistor R1 are connected to one end of the second switch K2 and one end of the second resistor R2, the other end of the second resistor R2 and the other end of the second switch K2 are connected to the voltage output unit 230, and the first switch K1 and the second switch K2 can be implemented through a relay, a triode, a MOSFET, a transmission gate, and the like; the control end of the first switch K1 is connected to the output end of the second comparator COMP2, the control end of the second switch K2 is connected to the output end of the first comparator COMP1, the first comparator COMP1 controls the on or off of the second switch K2, the second comparator COMP2 controls the on or off of the first switch K1, and further controls the connection states of the first resistor R1 and the second resistor R2 to change the voltage division of the reference voltage, so as to change the magnitude of the supply voltage output by the voltage output unit 230.
Further, the voltage output unit 230 includes a first operational amplifier OP1, a first MOS transistor Q1, a third resistor R3, and a fourth resistor R4; the non-inverting input end of the first operational amplifier OP1 is connected to a reference voltage input end, the inverting input end of the first operational amplifier OP1 is connected to the control unit 220 and one end of the fourth resistor R4, the output end of the first operational amplifier OP1 is connected to the gate of the first MOS transistor Q1, the source of the first MOS transistor Q1 is connected to the other end of the fourth resistor R4 and the constant current source module 400, and the drain of the first MOS transistor Q1 is connected to the voltage input end; one end of the third resistor R3 is connected to the control unit 220, and the other end of the third resistor R3 is grounded, and the voltage output unit 230 provides the power supply voltage VDD for the constant current source module 400 according to the reference voltage.
When the first comparator COMP1 and the second comparator COMP2 both output a low level signal, the first switch K1 and the second switch K2 are controlled to be turned off, and at this time, the first resistor R1 and the second resistor R2 are not shorted and connected to a circuit, and the supply voltage vdd=vref 3 (r4+r1+r2+r3)/(r1+r2+r3) is the first supply voltage; when the first comparator COMP1 outputs a high level signal, the second comparator COMP2 outputs a low level signal, controlling the second switch K2 to be turned on, and the first switch K1 is turned off, the second resistor R2 is short-circuited, and the supply voltage vdd=vref 3 (r4+r1+r3)/(r1+r3) is a second supply voltage; when the first comparator COMP1 and the second comparator COMP2 both output a high level, and the first switch K1 and the second switch K2 are controlled to be turned off, the first resistor R1 and the second resistor R2 are both shorted, and the supply voltage vdd=vref 3 (r4+r3)/R3 is the third supply voltage.
Therefore, by dividing the voltage value of the dimming signal into three parts (smaller than the first preset comparison voltage Vref1, larger than the first preset comparison voltage Vref1, smaller than the second preset comparison voltage Vref2, and larger than the second preset comparison voltage Vref 2), three different power supply voltages VDD are correspondingly generated, and the power supply voltage VDD has a low voltage value when the dimming signal voltage is low, and also has a high voltage value when the dimming signal voltage is high, compared with a mode of using only one VDD voltage, the difference between the power supply voltage VDD and the output voltage Vs of the constant current source module 400 is smaller, accordingly, when the LED lamp string 300 has a current flowing, the time from the output power supply voltage VDD to the stable output voltage Vs is shortened, the current variation range of the LED lamp string 300 is smaller, and thus the problems of light-emitting flicker of the LED lamp string 300 when the brightness is low, the power factor is improved, the harmonic value is reduced, and the conduction radiation caused by the current mutation of the LED lamp string 300 is improved.
Further, referring to fig. 4, in the second embodiment of the present invention, the control module 200 further includes a filtering unit 240, where the filtering unit 240 is configured to filter the dimming signal and output the filtered dimming signal to the comparing unit 210, in this embodiment, the PWM dimming signal is used as the dimming signal, the filtering unit 240 filters the input dimming signal to convert the dimming signal into an analog voltage signal, and then outputs the analog voltage signal to the first comparator COMP1 and the second comparator COMP2 to be compared respectively, so as to control the first switch K1 and the second switch K2, and since the working principles of the first comparator COMP1 and the second comparator COMP2 are the same as those of the first embodiment, the details are omitted.
Still further, the filtering unit 240 includes a capacitor C1 and a fifth resistor R5; one end of the capacitor C1 is connected to one end of the fifth resistor R5 and the comparing unit 210, and the other end of the capacitor C1 is grounded; the other end of the fifth resistor R5 is connected with a dimming signal input end, and filtering processing of the dimming signal is achieved through the fifth resistor R5 and the capacitor C1.
Further, the number of the LED strings 300 in the first embodiment and the second embodiment may be one or more, when the LED string 300 is one, as shown in fig. 5, that is, the LED control circuit is a single-segment LED string structure, and the corresponding constant current source module 400 controls the working current; in the single-segment LED string structure, when the line voltage output by the rectifying module 100 increases and is greater than the voltage of the LED string 300, the LED string 300 emits light according to the current set by the dimming voltage; when the line voltage output by the rectifying module 100 decreases and is smaller than the voltage of the LED string 300, no current flows through the LED string 300, and the LED string 300 does not emit light.
When there are a plurality of LED strings 300, as shown in fig. 6, the LED control circuit has a multi-segment LED string serial structure, in this embodiment, three segments of LED strings 300 (LED 1 string, LED2 string and LED3 string) are described in series, and of course, two segments, four segments or more segments may be also used, which is not limited in this invention, and three corresponding constant current source modules 400 are respectively provided to control the working current of each LED string 300; when the line voltage rises to be larger than the voltage of the LED1 lamp string and smaller than the voltage of the LED1+LED2 lamp string, the LED1 lamp string emits light according to the current set after the dimming voltage is divided; when the line voltage rises to be larger than the voltage of the LED1+LED2 lamp string and smaller than the voltage of the LED1+LED2+LED3 lamp string, the LED1 lamp string and the LED2 lamp string emit light according to the current set after the dimming voltage is divided, and the current is larger than the current when the LED1 lamp string emits light independently; when the line voltage continues to rise to be larger than the voltage of the LED1+LED2+LED3 lamp string, the LED1 lamp string, the LED2 lamp string and the LED3 lamp string emit light according to the current set after the dimming voltage is divided, and the current is larger than the current when the LED1+LED2 emits light together. Similarly, when the line voltage decreases, the current is turned off in the order of LED3-LED2-LED 1. Compared with the single-segment LED light string 300, the three-segment cascade structure has the advantages that in one line voltage period, the current of the LED light string 300 gradually increases along with the increase of the line voltage, the current of the LED light string 300 gradually decreases along with the decrease of the line voltage, and the LED light string 300 is lightened for a longer time, higher power factor, lower harmonic wave and higher light efficiency.
Further, referring to fig. 2, each constant current source module 400 includes a second operational amplifier OP2 and a second MOS transistor Q2, a power input end of the second operational amplifier OP2 in each constant current source module 400 is connected to the control module 200, a non-inverting input end of the second operational amplifier OP2 is connected to the control module 200, an inverting input end of the second operational amplifier OP2 is connected to one end of the sampling resistor and a source electrode of the second MOS transistor Q2, an output end of the second operational amplifier OP2 is connected to a gate electrode of the second MOS transistor Q2, and a drain electrode of the second MOS transistor Q2 is connected to the rectifying module 100.
In the first embodiment and the second embodiment, the supply voltage output by the control module 200 is input to the power input end of the second operational amplifier, for example, the power input end of the second operational amplifier OP22 in fig. 5, or the power input ends of the second operational amplifiers OP22, OP23, OP24 in fig. 6, the power input ends of the second operational amplifiers OP22, OP23, OP24 share the supply voltage output by the control module 200, the output voltage of the constant current source module 400 refers to the output voltage of the output end of the second operational amplifier, the voltage of the dimming signal is divided into three parts (smaller than the first preset comparison voltage Vref1 and larger than the first preset comparison voltage Vref 2), three different supply voltages are correspondingly generated, the voltage values of the supply voltages are low when the voltage of the dimming signal is low, the voltage values of the supply voltages are also higher than the voltage VDD, the voltage of the supply voltages are higher when the voltage of the dimming signal is low, the voltage of the supply voltages are higher than the voltage VDD, the voltage of the LED strings are higher than the second preset comparison voltage, the LED strings are LED to be LED light-emitting, and the LED strings are LED light-emitting current is LED light, and the LED strings are LED light emitting current is LED light emitting from the LED strings are LED light emitting to the LED light emitting the LED light.
Based on the above-mentioned self-adaptive driving circuit for an LED lamp, referring to fig. 7, the present invention further provides a driving method for the self-adaptive driving circuit for an LED lamp, which specifically includes the following steps:
s100, the control module outputs dimming voltage to the constant current source module according to an externally input dimming signal;
s200, the constant current source module adjusts the working current of the LED lamp string according to the dimming voltage;
and S300, the control module compares the voltage value of the dimming signal with at least one preset comparison voltage, and outputs a corresponding power supply voltage to the constant current source module according to the comparison result to control the difference value between the power supply voltage and the output voltage of the constant current source module.
Based on the LED control circuit, the invention further correspondingly provides an LED control device, which comprises a shell, wherein a PCB is arranged in the shell, and the LED control circuit is arranged on the PCB, and the LED control circuit is not described in detail herein.
In summary, the LED control device, the circuit and the control method thereof provided by the invention, wherein the LED control circuit comprises a control module, at least one LED string and constant current source modules corresponding to the number of the LED strings; the control module is used for outputting dimming voltage to the constant current source module according to an externally input dimming signal; the constant current source module is used for adjusting the working current of the LED lamp string according to the dimming voltage; the control module is further used for comparing the voltage value of the dimming signal with at least one preset comparison voltage, selecting a corresponding power supply voltage according to a comparison result, outputting the power supply voltage to the constant current source module, controlling the difference value between the power supply voltage and the output voltage of the constant current source module, and further avoiding the luminous flickering of the LED lamp string when the brightness is reduced and the conduction radiation caused by the abrupt change of the working current.
It will be understood that equivalents and modifications will occur to those skilled in the art in light of the present invention and their spirit, and all such modifications and substitutions are intended to be included within the scope of the present invention as defined in the following claims.
Claims (10)
1. The LED control circuit is characterized by comprising a control module, at least one LED lamp string and constant current source modules, wherein the number of the constant current source modules corresponds to that of the LED lamp strings; the control module is used for outputting dimming voltage to the constant current source module according to an externally input dimming signal; the constant current source module is used for adjusting the working current of the LED lamp string according to the dimming voltage; the control module is also used for comparing the voltage value of the dimming signal with at least one preset comparison voltage, selecting a corresponding power supply voltage according to the comparison result, outputting the power supply voltage to the constant current source module, and controlling and reducing the difference value between the power supply voltage and the output voltage of the constant current source module.
2. The LED control circuit of claim 1, wherein the control module is specifically configured to compare the voltage value of the dimming signal with a first preset comparison voltage and a second preset comparison voltage, and output a first supply voltage to the constant current source module when the voltage value of the dimming signal is less than the first preset comparison voltage; outputting a second power supply voltage to the constant current source module when the voltage value of the dimming signal is larger than the first preset comparison voltage and smaller than the second preset comparison voltage; outputting a third power supply voltage to the constant current source module when the voltage value of the dimming signal is larger than the second preset comparison voltage; the first preset comparison voltage is smaller than the second preset comparison voltage.
3. The LED control circuit of claim 2, wherein the control module comprises a comparison unit, a control unit, and a voltage output unit; the voltage output unit is used for outputting the power supply voltage to the constant current source module according to a reference voltage; the comparison unit is used for comparing the voltage value of the dimming signal with the first preset comparison voltage and the second preset comparison voltage, and outputting a corresponding level signal to the control unit according to a comparison result; and the control unit controls the voltage output unit to output corresponding power supply voltage to the constant current source module according to the level signal.
4. The LED control circuit of claim 3, wherein the comparison unit comprises a first comparator and a second comparator; the non-inverting input end of the first comparator is connected with the dimming signal input end, the inverting input end of the first comparator is connected with a first preset comparison voltage input end, and the output end of the first comparator is connected with the control unit; the positive phase input end of the second comparator is connected with the dimming signal input end, the negative phase input end of the second comparator is connected with the second preset comparison voltage input end, and the output end of the second comparator is connected with the control unit.
5. The LED control circuit of claim 3, wherein the control unit comprises a first switch, a second switch, a first resistor, and a second resistor; one end of the first switch is connected with the voltage output unit and one end of the first resistor, the other end of the first switch and the other end of the first resistor are connected with one end of the second switch and one end of the second resistor, and the other end of the second resistor and the other end of the second switch are connected with the voltage output unit; the control end of the first switch and the control end of the second switch are both connected with the comparison unit.
6. The LED control circuit of claim 3, wherein the voltage output unit comprises a first operational amplifier, a first MOS transistor, a third resistor, and a fourth resistor; the positive input end of the first operational amplifier is connected with a reference voltage input end, the negative input end of the first operational amplifier is connected with the control unit and one end of the fourth resistor, the output end of the first operational amplifier is connected with the grid electrode of the first MOS tube, the source electrode of the first MOS tube is connected with the other end of the fourth resistor and the constant current source module, and the drain electrode of the first MOS tube is connected with the voltage input end; one end of the third resistor is connected with the control unit, and the other end of the third resistor is grounded.
7. The LED control circuit of claim 3, wherein the control module further comprises a filtering unit, and the filtering unit is configured to filter the dimming signal and output the filtered dimming signal to the comparing unit.
8. The LED control circuit of claim 7, wherein the filter unit comprises a capacitor and a fifth resistor; one end of the capacitor is connected with one end of the fifth resistor and the comparison unit, and the other end of the capacitor is grounded; the other end of the fifth resistor is connected with the dimming signal input end.
9. A control method based on an LED control circuit according to any one of claims 1-8, comprising the steps of:
the control module outputs dimming voltage to the constant current source module according to an externally input dimming signal;
the constant current source module adjusts the working current of the LED lamp string according to the dimming voltage;
the control module is used for comparing the voltage value of the dimming signal with at least one preset comparison voltage, outputting a corresponding power supply voltage to the constant current source module according to the comparison result, and controlling the difference value between the power supply voltage and the output voltage of the constant current source module.
10. An LED control device comprising a housing, wherein a PCB board is arranged in the housing, characterized in that the PCB board is provided with the LED control circuit according to any one of claims 1-8.
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Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009070878A (en) * | 2007-09-11 | 2009-04-02 | Seiko Npc Corp | Led drive circuit |
| KR20110049519A (en) * | 2009-11-05 | 2011-05-12 | 삼성엘이디 주식회사 | Circuit for driving led and power supply for led comprising the same |
| CN202632722U (en) * | 2012-05-04 | 2012-12-26 | 福建捷联电子有限公司 | LED drive circuit |
| CN103024992A (en) * | 2012-11-13 | 2013-04-03 | 深圳麦格米特电气股份有限公司 | Dimming method of LED (Light Emitting Diode) streetlamp |
| CN204425733U (en) * | 2015-02-13 | 2015-06-24 | 浙江生辉照明有限公司 | For the supply power voltage regulating system of LED linear constant current circuit |
| CN105163431A (en) * | 2015-08-21 | 2015-12-16 | 上海艾为电子技术股份有限公司 | Drive circuit, light-emitting diode and mobile terminal |
| CN206164914U (en) * | 2016-10-13 | 2017-05-10 | 伊戈尔电气股份有限公司 | Linear constant current drive's LED light source prevent dark light circuit |
| CN107846745A (en) * | 2017-10-11 | 2018-03-27 | 杭州士兰微电子股份有限公司 | LED drive circuit and its control method |
| WO2018086244A1 (en) * | 2016-11-11 | 2018-05-17 | 深圳市明微电子股份有限公司 | Led linear constant current control circuit and led light emitting device |
| CN108495419A (en) * | 2018-04-28 | 2018-09-04 | 深圳市晟碟半导体有限公司 | A kind of LED light adjusting circuits, light modulating device and light-dimming method reducing harmonic distortion |
| EP3457814A1 (en) * | 2017-09-15 | 2019-03-20 | Yu Jing Energy Technology Co., Ltd. | Dimming control optimization system |
| CN110831279A (en) * | 2019-10-25 | 2020-02-21 | 深圳市晟碟半导体有限公司 | LED driving device, driving circuit and driving method thereof |
| CN211509379U (en) * | 2020-02-28 | 2020-09-15 | 深圳市晟碟半导体有限公司 | LED control device and circuit |
-
2020
- 2020-02-28 CN CN202010128530.XA patent/CN111200892B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009070878A (en) * | 2007-09-11 | 2009-04-02 | Seiko Npc Corp | Led drive circuit |
| KR20110049519A (en) * | 2009-11-05 | 2011-05-12 | 삼성엘이디 주식회사 | Circuit for driving led and power supply for led comprising the same |
| CN202632722U (en) * | 2012-05-04 | 2012-12-26 | 福建捷联电子有限公司 | LED drive circuit |
| CN103024992A (en) * | 2012-11-13 | 2013-04-03 | 深圳麦格米特电气股份有限公司 | Dimming method of LED (Light Emitting Diode) streetlamp |
| CN204425733U (en) * | 2015-02-13 | 2015-06-24 | 浙江生辉照明有限公司 | For the supply power voltage regulating system of LED linear constant current circuit |
| CN105163431A (en) * | 2015-08-21 | 2015-12-16 | 上海艾为电子技术股份有限公司 | Drive circuit, light-emitting diode and mobile terminal |
| CN206164914U (en) * | 2016-10-13 | 2017-05-10 | 伊戈尔电气股份有限公司 | Linear constant current drive's LED light source prevent dark light circuit |
| WO2018086244A1 (en) * | 2016-11-11 | 2018-05-17 | 深圳市明微电子股份有限公司 | Led linear constant current control circuit and led light emitting device |
| EP3457814A1 (en) * | 2017-09-15 | 2019-03-20 | Yu Jing Energy Technology Co., Ltd. | Dimming control optimization system |
| CN107846745A (en) * | 2017-10-11 | 2018-03-27 | 杭州士兰微电子股份有限公司 | LED drive circuit and its control method |
| CN108495419A (en) * | 2018-04-28 | 2018-09-04 | 深圳市晟碟半导体有限公司 | A kind of LED light adjusting circuits, light modulating device and light-dimming method reducing harmonic distortion |
| CN110831279A (en) * | 2019-10-25 | 2020-02-21 | 深圳市晟碟半导体有限公司 | LED driving device, driving circuit and driving method thereof |
| CN211509379U (en) * | 2020-02-28 | 2020-09-15 | 深圳市晟碟半导体有限公司 | LED control device and circuit |
Non-Patent Citations (1)
| Title |
|---|
| 基于自动跟踪LED驱动电压控制电路的创新设计;罗晓琴;;大学物理实验;第29卷(第06期);18-21 * |
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