LED power supply output current sampling circuit

Abstract

The utility model discloses an LED power supply output current sampling circuit, which relates to the technical field of LED power supplies, and comprises a power supply module used for supplying power; the power supply control module is used for electric energy transmission control; the constant-current driving module is used for current sampling and constant-current voltage stabilization regulation; the first LED module is used for illumination and current sampling; the second LED module is used for illumination and current sampling; the first sampling processing module and the second sampling processing module are both used for current and voltage conversion and signal amplification; and the fault judgment module is used for comparing the voltages of the signals output by the first sampling processing module and the second sampling processing module and carrying out fault judgment. The LED power supply output current sampling circuit provided by the utility model can carry out constant-current voltage-stabilizing power supply, independently carry out current sampling and signal processing on an LED group in a parallel state, timely judge current abnormity, carry out power-off protection, and improve the safety of the power supply.

Description

Technical Field

[0001] The utility model relates to the technical field of LED power supplies, in particular to an LED power supply output current sampling circuit. Background Art

[0002] LED, a light-emitting diode, is a commonly used light-emitting device that releases energy through the recombination of electrons and holes to emit light. It is widely used in the field of lighting. To ensure the stable operation of LEDs and extend the service life of LEDs, LED power supplies in the existing technology are generally composed of a constant current drive device, a field-effect transistor, and a sampling resistor. When driving one or more groups of LEDs, the LEDs can be driven with a constant current according to the current change state, and overcurrent protection can also be performed. However, when driving and sampling the current of multiple groups of LEDs in parallel, only the total current of the multiple groups of LEDs in parallel is sampled. When the current of one group of LEDs decreases and the current of the other group of LEDs increases, the total current will change less, resulting in the constant current drive device being unable to determine the current fault in time, which in turn causes damage to the LEDs. There are certain safety hazards, and therefore needs to be improved. Utility Model Content

[0003] The embodiment of the present invention provides an LED power supply output current sampling circuit to solve the problems raised in the above background technology.

[0004] To achieve the above objectives, the present invention provides the following technical solutions:

[0005] An LED power supply output current sampling circuit includes: a power supply module, a power supply control module, a constant current drive module, a first LED module, a second LED module, a first sampling processing module, a second sampling processing module and a fault judgment module;

[0006] a power module, configured to receive direct current power, filter and stabilize the direct current power, and output first power;

[0007] a power control module connected to the power module, the fault judgment module, the constant current drive module, the first LED module, and the second LED module, and configured to transmit the first electric energy to the constant current drive module, the first LED module, and the second LED module, and stop transmitting the first electric energy upon receiving a protection signal output by the fault judgment module;

[0008] a constant current driving module connected to the first LED module and the second LED module, configured to receive the first electric energy and perform constant current and voltage regulation on the electric energy input to the first LED module and the second LED module, perform current sampling on the first LED module and the second LED module, and adjust the operating electric energy of the first LED module and the second LED module according to the sampled first current signal;

[0009] The first LED module is used for performing lighting work and performing current sampling of working power energy to output a second current signal;

[0010] The second LED module is used for performing lighting work and performing current sampling of working power energy, and outputting a third current signal;

[0011] a first sampling and processing module, connected to the first LED module, configured to perform current-to-voltage conversion and amplification processing on the second current signal and output a first voltage signal;

[0012] a second sampling and processing module, connected to the second LED module, configured to perform current-to-voltage conversion and amplification processing on the third current signal and output a second voltage signal;

[0013] A fault judgment module is connected to the first sampling and processing module and the second sampling and processing module, and is used to compare the voltages of the first voltage signal and the second voltage signal, and output a protection signal when the voltage of the first voltage signal is greater than the voltage of the second voltage signal or the voltage of the second voltage signal is greater than the voltage of the first voltage signal.

[0014] As a further solution of the present invention: the constant current driving module includes a first resistor, a first diode, a third capacitor, a first driver, a first power tube and a second resistor;

[0015] Preferably, the first end of the first resistor is connected to the power control module, the second end of the first resistor is connected to the VDD end of the first driver and the cathode of the first diode and is connected to the anode of the first diode, the GND end of the first driver and one end of the second resistor through the third capacitor, the OUT end of the first driver is connected to the gate of the first power tube, the drain of the first power tube is connected to the first LED module and the second LED module, and the source of the first power tube is connected to the CS end of the first driver and the other end of the second resistor.

[0016] As a further solution of the present invention: the first LED module includes a first LED lamp and a third resistor; the second LED module includes a second LED lamp and a fourth resistor;

[0017] Preferably, the first end of the first LED lamp is connected to the first end of the second LED lamp and the power control module, the second end of the first LED lamp is connected to the first end of the third resistor and the first sampling and processing module, the second end of the second LED lamp is connected to the first end of the fourth resistor and the second sampling and processing module, and the second end of the third resistor is connected to the second end of the fourth resistor and the drain of the first power tube.

[0018] As a further solution of the present invention: the first sampling processing module includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a first operational amplifier; the second sampling processing module includes a signal conditioning device;

[0019] Preferably, one end of the fifth resistor is connected to the first end of the third resistor, the other end of the fifth resistor is connected to the non-inverting end of the first op amp and is grounded through the seventh resistor, one end of the sixth resistor is connected to the second end of the third resistor, the other end of the sixth resistor is connected to the inverting end of the first op amp and is connected to the output end of the first op amp through the eighth resistor, the first end and the second end of the signal conditioning device are respectively connected to the first end and the second end of the fourth resistor, and the third end of the signal conditioning device is connected to the fault judgment module.

[0020] As a further solution of the present invention: the fault judgment module includes a first comparator, a second comparator and a first logic chip;

[0021] Preferably, the non-inverting end of the first comparator is connected to the inverting end of the second comparator and the output end of the first op amp, the inverting end of the first comparator is connected to the non-inverting end of the second comparator and the third end of the signal conditioning device, the output end of the first comparator is connected to the B end of the first logic chip, the output end of the second comparator is connected to the A end of the first logic chip, and the Y end of the first logic chip is connected to the power control module.

[0022] As a further solution of the present invention: the power control module includes a ninth resistor, a second power tube and a first switch tube;

[0023] Preferably, the drain of the second power tube is connected to the second end of the first voltage regulator and one end of the second capacitor and is connected to the gate of the second power tube and the collector of the first switching tube through a ninth resistor, the emitter of the first switching tube is connected to the first end of the first voltage regulator and the ground end, the base of the first switching tube is connected to the Y end of the first logic chip, the source of the second power tube is connected to the first end of the first resistor and the first end of the first LED lamp, the third end of the first voltage regulator is connected to the first end of the power interface and is connected to the second end of the power interface, the first end of the first voltage regulator, the other end of the second capacitor and the ground end through the first capacitor.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: the output current sampling circuit of the LED power supply of the present invention can perform current sampling on the first LED module and the second LED module by the constant current driving module and perform constant current and voltage stabilization driving control on the first LED module and the second LED module; at the same time, the first sampling processing module performs current sampling and signal processing on the first LED module alone, and the second sampling processing module performs current sampling and signal processing on the second LED module alone; the fault judgment module detects whether the operating currents of the first LED module and the second LED module are the same, and if they are not equal, it is judged that the first LED module and the second LED module have a fault, and the power control module is directly controlled to perform power-off control, thereby improving the safety of the LED power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 This is a schematic diagram of the principle of an LED power supply output current sampling circuit provided by an example of the present utility model.

[0027] Figure 2 This is a circuit diagram of an LED power supply output current sampling circuit provided by an example of the present utility model.

[0028] Figure 3 This is a connection circuit diagram of the power control module provided by an example of the present utility model. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] In one embodiment, see Figure 1 , an LED power supply output current sampling circuit, comprising: a power supply module 1, a power supply control module 2, a constant current driving module 3, a first LED module 4, a second LED module 5, a first sampling processing module 6, a second sampling processing module 7 and a fault judgment module 8;

[0031] Specifically, the power module 1 is used to receive direct current power, filter and stabilize the direct current power, and output the first power;

[0032] a power control module 2 connected to the power module 1, the fault judgment module 8, the constant current drive module 3, the first LED module 4 and the second LED module 5, configured to transmit the first electric energy to the constant current drive module 3, the first LED module 4 and the second LED module 5, and stop transmitting the first electric energy upon receiving a protection signal output by the fault judgment module 8;

[0033] a constant current driving module 3 connected to the first LED module 4 and the second LED module 5, configured to receive the first electrical energy and perform constant current and voltage regulation on the electrical energy input to the first LED module 4 and the second LED module 5, perform current sampling on the first LED module 4 and the second LED module 5, and adjust the operating electrical energy of the first LED module 4 and the second LED module 5 according to the sampled first current signal;

[0034] The first LED module 4 is used for performing lighting work and performing current sampling of working power energy, and outputting a second current signal;

[0035] The second LED module 5 is used for performing lighting work and sampling the current of the working power energy, and outputting a third current signal;

[0036] a first sampling and processing module 6 connected to the first LED module 4, configured to perform current-to-voltage conversion and amplification processing on the second current signal and output a first voltage signal;

[0037] a second sampling and processing module 7 connected to the second LED module 5, configured to perform current-to-voltage conversion and amplification processing on the third current signal and output a second voltage signal;

[0038] The fault judgment module 8 is connected to the first sampling and processing module 6 and the second sampling and processing module 7, and is used to compare the voltages of the first voltage signal and the second voltage signal, and output a protection signal when the voltage of the first voltage signal is greater than the voltage of the second voltage signal or the voltage of the second voltage signal is greater than the voltage of the first voltage signal.

[0039] In a specific embodiment, the power supply module 1 can adopt a power supply circuit composed of a power supply interface, a capacitor and a voltage stabilizer, can be connected to DC power, the DC power can be provided by a battery, and the DC power can be filtered and stabilized; the power control module 2 can adopt a power supply control circuit composed of a resistor, a field effect transistor and a resistor, which can control the transmission state of the power; the constant current drive module 3 can adopt a constant current drive circuit composed of a constant current drive device, a field effect transistor, a resistor, etc., which can detect the current state when the first LED module 4 and the second LED module 5 are connected in parallel, and perform constant current and voltage regulation on the power input to the first LED module 4 and the second LED module 5; the first LED module 4 can adopt a first LED lamp composed of a resistor D circuit, which can perform lighting work and sample and process the current during operation; the above-mentioned second LED module 5 can adopt a second LED circuit composed of an LED lamp and a resistor, which can perform lighting work and sample and process the current during operation; the above-mentioned first sampling processing module 6 can adopt a first sampling processing circuit composed of a resistor and an operational amplifier, which performs current-voltage conversion processing on the input signal and amplifies the converted electric energy; the above-mentioned second sampling processing module 7 can adopt a first sampling processing circuit composed of a signal conditioning device, which performs current-voltage conversion processing on the input signal and amplifies the converted electric energy; the above-mentioned fault judgment module 8 can adopt a fault judgment circuit composed of a comparator to compare the voltage magnitude relationship of the input signal.

[0040] In another embodiment, see Figure 1 、 Figure 2 and Figure 3 The constant current driving module 3 includes a first resistor R1, a first diode D1, a third capacitor C3, a first driver IC2, a first power tube Q1 and a second resistor R2;

[0041] Specifically, the first end of the first resistor R1 is connected to the power control module 2, the second end of the first resistor R1 is connected to the VDD end of the first driver IC2 and the cathode of the first diode D1 and is connected to the anode of the first diode D1, the GND end of the first driver IC2 and one end of the second resistor R2 through the third capacitor C3, the OUT end of the first driver IC2 is connected to the gate of the first power tube Q1, the drain of the first power tube Q1 is connected to the first LED module 4 and the second LED module 5, and the source of the first power tube Q1 is connected to the CS end of the first driver IC2 and the other end of the second resistor R2.

[0042] In a specific embodiment, the first driver IC2 may be a QX7136 constant current driver; the second resistor R2 is used as a current sampling resistor; and the first power transistor Q1 may be an N-channel field effect transistor.

[0043] Furthermore, the first LED module 4 includes a first LED lamp and a third resistor R3; the second LED module 5 includes a second LED lamp and a fourth resistor R4;

[0044] Specifically, the first end of the first LED lamp is connected to the first end of the second LED lamp and the power control module 2, the second end of the first LED lamp is connected to the first end of the third resistor R3 and the first sampling and processing module 6, the second end of the second LED lamp is connected to the first end of the fourth resistor R4 and the second sampling and processing module 7, and the second end of the third resistor R3 is connected to the second end of the fourth resistor R4 and the drain of the first power tube Q1.

[0045] In a specific embodiment, the third resistor R3 performs current sampling processing on the first LED lamp, and the fourth resistor R4 performs current sampling processing on the second LED lamp.

[0046] Furthermore, the first sampling processing module 6 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a first operational amplifier OP1; the second sampling processing module 7 includes a signal conditioning device;

[0047] Specifically, one end of the fifth resistor R5 is connected to the first end of the third resistor R3, the other end of the fifth resistor R5 is connected to the non-inverting end of the first operational amplifier OP1 and is grounded through the seventh resistor R7, one end of the sixth resistor R6 is connected to the second end of the third resistor R3, the other end of the sixth resistor R6 is connected to the inverting end of the first operational amplifier OP1 and is connected to the output end of the first operational amplifier OP1 through the eighth resistor R8, the first end and the second end of the signal conditioning device are respectively connected to the first end and the second end of the fourth resistor R4, and the third end of the signal conditioning device is connected to the fault judgment module 8.

[0048] In a specific embodiment, the above-mentioned first operational amplifier OP1 can select an OP07 operational amplifier, and cooperate with the fifth resistor R5, the sixth resistor R6, the seventh resistor R7 and the eighth resistor R8 to convert the input current signal into a voltage signal and perform signal amplification processing; the circuit composition structure of the above-mentioned signal conditioning device is the same as the circuit composition structure of the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8 and the first operational amplifier OP1, and realizes current-voltage signal conversion and signal amplification.

[0049] Furthermore, the fault judgment module 8 includes a first comparator A1, a second comparator A2 and a first logic chip IC3;

[0050] Specifically, the non-inverting terminal of the first comparator A1 is connected to the inverting terminal of the second comparator and the output terminal of the first operational amplifier OP1, the inverting terminal of the first comparator A1 is connected to the non-inverting terminal of the second comparator A2 and the third terminal of the signal conditioning device, the output terminal of the first comparator A1 is connected to the B terminal of the first logic chip IC3, the output terminal of the second comparator A2 is connected to the A terminal of the first logic chip IC3, and the Y terminal of the first logic chip IC3 is connected to the power control module 2.

[0051] In a specific embodiment, both the first comparator A1 and the second comparator A2 can be LM358 comparators; and the first logic chip IC3 can be an XOR gate chip.

[0052] Furthermore, the power control module 2 includes a ninth resistor R9, a second power tube Q2 and a first switch tube V1; the power module 1 includes a power interface, a first capacitor C1, a second capacitor C2 and a first voltage regulator IC1;

[0053] Specifically, the drain of the second power tube Q2 is connected to the second end of the first voltage regulator IC1 and one end of the second capacitor C2 and is connected to the gate of the second power tube Q2 and the collector of the first switch tube V1 through the ninth resistor R9. The emitter of the first switch tube V1 is connected to the first end of the first voltage regulator IC1 and the ground end. The base of the first switch tube V1 is connected to the Y end of the first logic chip IC3. The source of the second power tube Q2 is connected to the first end of the first resistor R1 and the first end of the first LED lamp. The third end of the first voltage regulator IC1 is connected to the first end of the power interface and is connected to the second end of the power interface, the first end of the first voltage regulator IC1, the other end of the second capacitor C2 and the ground end through the first capacitor C1.

[0054] In a specific embodiment, the second power tube Q2 may be an N-channel field effect tube; the first switch tube V1 may be an NPN transistor; and the first voltage regulator IC1 may be an LM317 voltage regulator.

[0055] In an LED power supply output current sampling circuit of this embodiment, DC power is connected to the power interface, the first capacitor C1, the second capacitor C2 and the first voltage regulator IC1 perform voltage regulation processing, the second power tube Q2 transmits the power output by the first voltage regulator IC1, so that the first driver IC2 adjusts the conduction degree of the first power tube Q1 according to the current signal sampled by the second resistor R2, and then performs constant current and voltage regulation drive control on the first LED lamp and the second LED lamp. At the same time, the third resistor R3 and the fourth resistor R4 respectively perform current sampling processing on the first LED lamp and the second LED lamp, and the first operational amplifier OP1 cooperates with the fifth resistor R5, the sixth resistor R6 and the seventh resistor R7 to generate a constant current. Resistor R7 and the eighth resistor R8 convert the signal sampled by the third resistor R3 into a voltage signal and perform signal amplification processing. The signal sampled by the fourth resistor R4 is converted into a current-voltage signal and amplified by the signal conditioning device. When the voltage of the signal output by the first operational amplifier is greater than the voltage of the signal output by the signal conditioning device, the first comparator A1 outputs a high level, controls the first switch tube V1 to be turned on, the first power tube Q1 to be turned off, and power-off protection is performed. When the voltage of the signal output by the first operational amplifier OP1 is less than the voltage of the signal output by the signal conditioning device, the second comparator A2 outputs a high level, turns on the first switch tube V1, and turns off the first power tube Q1 to perform power-off protection.

[0056] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0057] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An LED power supply output current sampling circuit, characterized in that: The LED power supply output current sampling circuit includes: a power supply module, a power supply control module, a constant current driving module, a first LED module, a second LED module, a first sampling processing module, a second sampling processing module and a fault judgment module; The power supply module is used to receive direct current power, filter and stabilize the direct current power, and output the first power; The power control module is connected to the power module, the fault judgment module, the constant current drive module, the first LED module and the second LED module, and is used to transmit the first power to the constant current drive module, the first LED module and the second LED module, and stop transmitting the first power when receiving the protection signal output by the fault judgment module; The constant current driving module is connected to the first LED module and the second LED module, and is used to receive the first electric energy and perform constant current and voltage regulation on the electric energy input to the first LED module and the second LED module, perform current sampling on the first LED module and the second LED module, and adjust the working electric energy of the first LED module and the second LED module according to the sampled first current signal; The first LED module is used to perform lighting work and perform current sampling of working power energy to output a second current signal; The second LED module is used to perform lighting work and perform current sampling of working power energy to output a third current signal; The first sampling and processing module is connected to the first LED module and is used to perform current-to-voltage conversion and amplification processing on the second current signal and output a first voltage signal; The second sampling and processing module is connected to the second LED module, and is used to perform current-to-voltage conversion and amplification processing on the third current signal and output a second voltage signal; The fault judgment module is connected to the first sampling and processing module and the second sampling and processing module, and is used to compare the voltages of the first voltage signal and the second voltage signal, and output a protection signal when the voltage of the first voltage signal is greater than the voltage of the second voltage signal or the voltage of the second voltage signal is greater than the voltage of the first voltage signal.

2. The LED power supply output current sampling circuit according to claim 1, characterized in that: The constant current driving module includes a first resistor, a first diode, a third capacitor, a first driver, a first power tube and a second resistor; The first end of the first resistor is connected to the power control module, the second end of the first resistor is connected to the VDD end of the first driver and the cathode of the first diode and is connected to the anode of the first diode, the GND end of the first driver and one end of the second resistor through the third capacitor, the OUT end of the first driver is connected to the gate of the first power tube, the drain of the first power tube is connected to the first LED module and the second LED module, and the source of the first power tube is connected to the CS end of the first driver and the other end of the second resistor.

3. The LED power supply output current sampling circuit according to claim 2, characterized in that: The first LED module includes a first LED lamp and a third resistor; the second LED module includes a second LED lamp and a fourth resistor; The first end of the first LED lamp is connected to the first end of the second LED lamp and the power control module, the second end of the first LED lamp is connected to the first end of the third resistor and the first sampling and processing module, the second end of the second LED lamp is connected to the first end of the fourth resistor and the second sampling and processing module, and the second end of the third resistor is connected to the second end of the fourth resistor and the drain of the first power tube.

4. The LED power supply output current sampling circuit according to claim 3, characterized in that: The first sampling processing module includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a first operational amplifier; the second sampling processing module includes a signal conditioning device; One end of the fifth resistor is connected to the first end of the third resistor, the other end of the fifth resistor is connected to the non-inverting end of the first operational amplifier and is grounded through the seventh resistor, one end of the sixth resistor is connected to the second end of the third resistor, the other end of the sixth resistor is connected to the inverting end of the first operational amplifier and is connected to the output end of the first operational amplifier through the eighth resistor, the first end and the second end of the signal conditioning device are respectively connected to the first end and the second end of the fourth resistor, and the third end of the signal conditioning device is connected to the fault judgment module.

5. The LED power supply output current sampling circuit according to claim 4, characterized in that: The fault judgment module includes a first comparator, a second comparator and a first logic chip; The non-inverting end of the first comparator is connected to the inverting end of the second comparator and the output end of the first op amp, the inverting end of the first comparator is connected to the non-inverting end of the second comparator and the third end of the signal conditioning device, the output end of the first comparator is connected to the B end of the first logic chip, the output end of the second comparator is connected to the A end of the first logic chip, and the Y end of the first logic chip is connected to the power control module.

6. The LED power supply output current sampling circuit according to claim 5, characterized in that: The power control module includes a ninth resistor, a second power tube and a first switching tube; the power module includes a power interface, a first capacitor, a second capacitor and a first voltage regulator; the drain of the second power tube is connected to the second end of the first voltage regulator and one end of the second capacitor and is connected to the gate of the second power tube and the collector of the first switching tube through the ninth resistor, the emitter of the first switching tube is connected to the first end of the first voltage regulator and the ground end, the base of the first switching tube is connected to the Y end of the first logic chip, the source of the second power tube is connected to the first end of the first resistor and the first end of the first LED lamp, the third end of the first voltage regulator is connected to the first end of the power interface and is connected to the second end of the power interface, the first end of the first voltage regulator, the other end of the second capacitor and the ground end through the first capacitor.

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