CN210120681U

CN210120681U - LED constant power regulation and control circuit

Info

Publication number: CN210120681U
Application number: CN201822243576.7U
Authority: CN
Inventors: 田宝军; 安飞虎; 李欣
Original assignee: Shenzhen Fei Rui Polytron Technologies Inc
Current assignee: Shenzhen Fei Rui Polytron Technologies Inc
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2020-02-28
Anticipated expiration: 2028-12-28

Abstract

The utility model discloses a LED constant power regulation and control circuit relates to the electronic product field, including host system, operational amplification module, current adjustment module, sampling module and LED banks, the input of operational amplification module is connected respectively to host system's output and sampling module's output, and current adjustment circuit's input is connected to operational amplifier's output, and current adjustment module's output is connected to sampling module's input, and current adjustment module is connected with the negative pole of LED banks, and the positive pole of LED banks and power supply's anodal the connection. The utility model discloses a different reference voltage of host system output, provide multiple constant current for the LED banks through control operational amplification module and current regulation module, need not to adjust the electric current through multichannel current-limiting circuit, have that the circuit is simple, power regulation is convenient, the adjustable gear is numerous not influenced by LED pressure drop individual difference and supply voltage's advantage, but wide application in various electronic products such as beauty instrument, fruit vegetables cultivation lighting apparatus.

Description

LED constant power regulation and control circuit

Technical Field

The utility model belongs to the technical field of the electronic product and specifically relates to a LED constant power regulation and control circuit.

Background

Electronic products such as beauty instrument, fruit and vegetable cultivation lighting apparatus need send specific wavelength, the light of specific power, consequently, need the LED lamp plate to be in the operating condition of constant current constant power, general simple control circuit carries out the constant voltage power supply for the lamp plate, adopt the mode that changes current-limiting resistance and adjust LED lamp plate operating current simultaneously to realize, but when the luminous intensity output of needs more shelves, required current-limiting resistance branch road is too many, and because there is great deviation in LED pressure drop value individual, the LED quantity of series connection is big more, the pressure drop difference is big more, still can lead to the operating current and the output power of lamp plate to produce obvious change, influence electronic product's result of use.

SUMMERY OF THE UTILITY MODEL

The present invention aims at solving at least one of the technical problems in the related art to a certain extent. Therefore, an object of the present invention is to provide a LED constant power regulation circuit with simple structure, convenient power regulation and no influence from individual difference of LED voltage drop and power supply voltage.

The utility model adopts the technical proposal that:

the utility model provides a LED constant power regulation and control circuit, including power supply, host system, operational amplification module, current adjustment module, sampling module and LED banks, host system is used for exporting different reference voltage, host system's output with sampling module's output is connected respectively the input of operational amplification module, the output of operational amplification module is connected current adjustment circuit's input, sampling module's input is connected current adjustment module's output, current adjustment module with the negative pole of LED banks is connected, the positive pole of LED banks with power supply's anodal connection.

Furthermore, the operational amplification module comprises an operational amplifier, the non-inverting input end of the operational amplifier is connected with the output end of the main control module, the inverting input end of the operational amplifier is connected with the output end of the sampling module, and the output end of the operational amplifier is connected with the input end of the current adjustment module.

Further, the current regulation module comprises a first triode, a first resistor and a third resistor, wherein the base of the first triode is connected with one end of the third resistor, the other end of the third resistor is connected with the output end of the operational amplifier, the collector of the first triode is connected with the negative electrode of the LED lamp bank, the emitter of the first triode is connected with the input end of the sampling module, one end of the first resistor is connected with the collector of the first triode, and the other end of the first resistor is connected with the emitter of the first triode.

Furthermore, the sampling module comprises a second resistor and a fourth resistor, one end of the second resistor is connected with the emitter of the first triode, the other end of the second resistor is grounded, one end of the fourth resistor is connected with the emitter of the first triode, and the other end of the fourth resistor is connected with the inverting input end of the operational amplification module.

Further, the sampling module further comprises a first capacitor, and the first capacitor is connected in parallel with the fourth resistor.

Further, still include the reference voltage module, the input of reference voltage module is connected host system's output, the output of reference voltage module is connected operational amplification module's input, the reference voltage module includes fifth resistance, sixth resistance and third electric capacity, the one end of fifth resistance is connected host system's output, the other end of fifth resistance is connected operational amplifier's in-phase input end, the one end of sixth resistance is connected operational amplifier's in-phase input end, the other end ground connection of sixth resistance, the third electric capacity with sixth resistance is parallelly connected.

The output end of the voltage stabilizing module is connected with the power supply input end of the operational amplifier and is used for providing working voltage for the operational amplifier module.

Further, the operational amplifier is BU7242 or LM 358.

Further, the main control module comprises a single chip microcomputer with a DAC level output function.

The utility model has the advantages that:

the utility model discloses a different reference voltage of host system output provides multiple constant current for the LED banks through control operational amplification module and current regulation module, need not to regulate and control the electric current through multichannel current-limiting circuit, has that the circuit is simple, power regulation is convenient, adjustable gear is numerous, do not receive the advantage that LED pressure drop individual difference and supply voltage influence.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of an LED constant power regulation circuit according to the present invention;

FIG. 2 is a circuit diagram of another embodiment of the LED constant power control circuit of the present invention

Fig. 3 is a circuit diagram of an embodiment of the present invention, which is a constant power LED control circuit.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

As shown in fig. 1, fig. 1 is a schematic structural diagram of a specific embodiment of an LED constant power regulation and control circuit of the present invention, which includes a power supply, and is characterized by including: the LED lamp set comprises a main control module, an operational amplification module, a current adjustment module, a sampling module and an LED lamp set, wherein the main control module is used for outputting different reference voltages, the output end of the main control module and the output end of the sampling module are respectively connected with the input end of the operational amplification module, the output end of the operational amplification module is connected with the input end of a current adjustment circuit, the input end of the sampling module is connected with the output end of the current adjustment module, the current adjustment module is connected with the negative electrode of the LED lamp set, and the positive electrode of the LED lamp set is connected with the positive electrode of a power supply.

The main control module outputs different reference voltages, the sampling module samples the output current of the current adjusting module, the operational amplification module controls the output end current of the current adjusting module, when the output voltage of the main control module is compared with the sampling voltage of the sampling module, when the output voltage of the main control module is equal to the sampling voltage of the sampling module, the LED constant power regulating and controlling circuit enters a normal working state, the working current of the LED lamp bank is the output current of the current adjusting module and is irrelevant to the output voltage of a power supply, and when the current and the output power of the LED lamp bank are to be adjusted, only the output voltage of the main control module needs to be adjusted.

Fig. 2 is a schematic diagram of another embodiment of the present invention, further including a voltage stabilizing module and a reference voltage module, wherein an output terminal of the voltage stabilizing module is connected to an input terminal of the operational amplifier module, the voltage stabilizing module provides a working voltage for the operational amplifier module, an input terminal of the reference voltage module is connected to an output terminal of the main control module, an output terminal of the reference voltage module is connected to an input terminal of the operational amplifier module to perform a voltage dividing function,

as shown in fig. 3, fig. 3 is a circuit diagram of an embodiment of an LED constant power control circuit according to the present invention, which includes an LED lamp set, the main control module is a single chip with a DAC level output function, a DAC port of the single chip outputs a reference voltage V _ REF, the operational amplification module includes an operational amplifier U1, the current adjustment module includes a first triode Q1, a first resistor R1 and a third resistor, the sampling module includes a second resistor R2, a fourth resistor R4 and a first capacitor C1, the LED lamp set includes eight LED beads from LED1 to LED8, an anode of the LED lamp set is connected to a power supply VDD, a cathode of the LED lamp set is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is grounded, a collector of the first triode Q1 is connected to a middle node of the cathodes of the first resistor Q1 and the emitter of the first triode Q45 is connected to a middle node R85 2, the base of a first triode Q1 is connected with one end of a third resistor R3, the other end of a third resistor R3 is connected with the output end of an operational amplifier U1, the operational amplifier U1 is powered by VCC, one end of a second capacitor C2 is connected with VCC, the other end of a second capacitor C2 is grounded, the non-inverting input end of the operational amplifier is connected with one end of a fifth resistor R5, the other end of the fifth resistor R5 is connected with the output end of a single-chip DAC, the inverting input end of the operational amplifier U1 is connected with one end of a fourth resistor R4, the other end of the fourth resistor R4 is connected with the middle node of the first resistor R1 and the second resistor R2, the first capacitor C1 is connected with the fourth resistor R4 in parallel, one end of a third capacitor C3 is connected with the non-inverting input end of the operational amplifier U1, the other end of the third capacitor C3 is grounded, and the sixth.

When the LED banks is in the bright operating condition entirely, thereby the accessible is adjusted the operating current of LED banks and is played the output who adjusts the LED banks, and the concrete principle is: the DAC port of the single chip microcomputer outputs a preset value of direct current voltage V _ REF which is divided by a fifth resistor R5 and a sixth resistor R6 and then is used as a reference voltage to be input to a non-inverting input port of an operational amplifier U1, the first triode Q1 is not conducted initially, therefore, the voltage at two ends of the second resistor R2 is the divided voltage of a power supply VDD through an LED lamp set, a first resistor R1, a second resistor R2 and a second resistor R2 on a ground node branch circuit, the voltage at two ends of the second resistor is small and is fed back to an inverting input end of the operational amplifier U1 through the fourth resistor R4, at the moment, the voltage at the non-inverting input end of the operational amplifier U1 is larger than the voltage at the inverting input end, the output end of the operational amplifier U1 outputs a high level, and the first triode Q1 is conducted. After the first triode Q1 is turned on, because the resistance value of the first resistor R1 is large, it can be considered that the first triode Q1 short-circuits the first resistor R1, so the current at the two ends of the second resistor R2 increases, the voltage at the two ends of the second resistor R2 increases, the voltage at the inverting input end of the first operational amplifier U1 increases, when the voltage at the non-inverting input end of the operational amplifier U1 is almost equal to the voltage at the inverting input end, a dynamic balance is achieved, at this time, the voltage value at the output end of the operational amplifier U1 is a fixed value, the first triode is in an amplification working interval, because the base current output by the first triode Q1 is small (only 2-3 mA at most), and can be ignored approximately compared with the working current of the LED lamp group, the working current of the LED lamp group ≈ the voltage at the two ends of the second resistor R2 (i.e. the non-inverting input voltage of the operational amplifier U1 ≈ R6326 ≈ the non-inverting input voltage of the first operational amplifier U1) (i.e. ≈ the voltage ≈ V ≈ R2 ≈ R638 .

Therefore, the working current and the output power of the LED lamp set can be adjusted by adjusting the DAC output voltage V _ REF of the single chip microcomputer or the resistance value of the second resistor R2.

When the LED lamp set is in the standby mode, the LED lamp set needs to emit dim light (indicating that the LED lamp set is in the LED light output working mode) to avoid over stimulating eyes, and at this time, V _ REF output by the DAC port of the single chip microcomputer is 0V, so that the input voltage of the non-inverting input terminal of the operational amplifier U1 is 0V. Because the power supply VDD is fed back to the ground through the LED lamp group, the first resistor R1, and the second resistor R2, a voltage drop exists at two ends of the second resistor R2, and the power supply VDD is fed back to the inverting input terminal of the operational amplifier U1 through the fourth resistor R4 and the first capacitor C1, so that the voltage of the inverting input terminal of the 6 th pin of the operational amplifier U1 is higher than the 0V voltage of the non-inverting input terminal, the output terminal of the operational amplifier U1 outputs a low level of 0V, the transistor Q1 is turned off, and the standby current of the LED lamp group is (VDD-LED lamp group voltage drop) ÷ (R1+ R2), because the second resistor R2 is much smaller than the first resistor R1, the standby current and the brightness of the LED lamp group are determined by the first resistor R1, and the standby light-emitting brightness of the LED lamp group is darker as the first resistor R1 is larger, specifically determined by the.

Specifically, the model of the operational amplifier U1 can be selected as BU7242 or LM358 operational amplifier, and the model of the single chip microcomputer with DAC output function can be selected as PIC16F 1937. For the application occasions that the power supply voltage VDD of the LED group is 20V, the red LED lamp group is 8, and the power supply voltage VCC of the operational amplifier U1 is 3V, the first transistor Q1 may select an NPN transistor with a current resistance of 200mA, a power of 0.35W, and a voltage resistance of 50V or more, such as a42 or 2N5551, and the first resistor R1 may select 100K to 120K ohms, so as to ensure that the luminance of the LED lamp group does not glary to eyes in the standby dim-bright mode (at this time, the first transistor Q1 is turned off). Because the single-chip DAC has a certain voltage jump interval between output voltages corresponding to each adjacent D/A value, the aim of precisely regulating and controlling the current is achieved by matching with the selection of the resistance value of the second resistor R2, and the second resistor R2 can be 6.2-6.8 ohms (depending on the working current of the LED group). The bypass capacitor of the operational amplifier U1, the second capacitor C2, the filter capacitor, the first capacitor C1, the third capacitor C3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the first capacitor C2, the third capacitor C3, the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6 are respectively 100nF, 10 kQ, 330 kQ 1% ohm and 220 kQ 1% ohm, respectively. When the model of the operational amplifier U1 is BU7242, the highest voltage of the 7 th pin of the output end can reach about 2.22V when the power supply VCC is 3V, and the third resistor R3 can select 750 ohms; if the operational amplifier U1 selects the LM358 operational amplifier IC, because of the influence of different internal voltage drops of the operational amplifier IC, the highest output voltage of the 7 th pin can only reach about 1.7V when the power supply VCC is 3V, so the third resistor R3 needs to be correspondingly reduced to 330 ohms, so as to ensure that the first triode Q1 can reach the same maximum base current and maximum conduction degree as those of the BU7242 operational amplifier IC, and the maximum regulation range of the working current of the LED lamp bank can be as large.

The operational amplifier U1 adopts a three-terminal voltage-stabilizing IC to supply power to VCC, so as to ensure the stability of the control voltage output by the 7 th pin of the operational amplifier U1, thereby the current of the LED lamp set is also kept stable, and the three-terminal voltage-stabilizing IC can select the types of HT7530 (voltage-stabilizing output 3.0V) and the like with higher input voltage and output current.

While the preferred embodiments of the present invention have been described, the present invention is not limited to the embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and such equivalent modifications or substitutions are intended to be included within the scope of the present invention as defined by the appended claims.

Claims

1. The utility model provides a LED constant power regulation and control circuit, includes power supply, its characterized in that includes: the LED lamp set comprises a main control module, an operational amplification module, a current adjustment module, a sampling module and an LED lamp set, wherein the main control module is used for outputting different reference voltages, the output end of the main control module and the output end of the sampling module are respectively connected with the input end of the operational amplification module, the output end of the operational amplification module is connected with the input end of a current adjustment circuit, the input end of the sampling module is connected with the output end of the current adjustment module, the current adjustment module is connected with the negative electrode of the LED lamp set, and the positive electrode of the LED lamp set is connected with the positive electrode of a power supply.

2. The LED constant power regulation and control circuit of claim 1, wherein the operational amplification module comprises an operational amplifier, a non-inverting input terminal of the operational amplifier is connected to the output terminal of the main control module, an inverting input terminal of the operational amplifier is connected to the output terminal of the sampling module, and an output terminal of the operational amplifier is connected to the input terminal of the current adjustment module.

3. The LED constant power regulation circuit of claim 2, wherein the current regulation module comprises a first transistor, a first resistor and a third resistor, a base of the first transistor is connected to one end of the third resistor, the other end of the third resistor is connected to the output terminal of the operational amplifier, a collector of the first transistor is connected to the negative electrode of the LED lamp set, an emitter of the first transistor is connected to the input terminal of the sampling module, one end of the first resistor is connected to the collector of the first transistor, and the other end of the first resistor is connected to the emitter of the first transistor.

4. The LED constant power regulation and control circuit according to claim 3, wherein the sampling module comprises a second resistor and a fourth resistor, one end of the second resistor is connected to the emitter of the first triode, the other end of the second resistor is grounded, one end of the fourth resistor is connected to the emitter of the first triode, and the other end of the fourth resistor is connected to the inverting input terminal of the operational amplification module.

5. The LED constant power regulation circuit of claim 4, wherein the sampling module further comprises a first capacitor, and the first capacitor is connected in parallel with the fourth resistor.

6. The LED constant power regulation and control circuit according to claim 2, further comprising a reference voltage module, wherein an input terminal of the reference voltage module is connected to an output terminal of the main control module, an output terminal of the reference voltage module is connected to an input terminal of the operational amplification module, the reference voltage module comprises a fifth resistor, a sixth resistor and a third capacitor, one end of the fifth resistor is connected to the output terminal of the main control module, the other end of the fifth resistor is connected to a non-inverting input terminal of the operational amplifier, one end of the sixth resistor is connected to a non-inverting input terminal of the operational amplifier, the other end of the sixth resistor is grounded, and the third capacitor is connected in parallel with the sixth resistor.

7. The LED constant power regulation and control circuit according to claim 2, further comprising a voltage stabilization module, wherein an output end of the voltage stabilization module is connected to a power input end of the operational amplifier, and is configured to provide an operating voltage for the operational amplification module.

8. The LED constant power regulation circuit of claim 2, wherein the operational amplifier is BU7242 or LM 358.

9. The LED constant power regulation and control circuit of claim 1, wherein the master control module comprises a single chip with DAC level output function.