CN218940677U

CN218940677U - Multi-series-parallel ultraviolet LED anti-breakdown circuit

Info

Publication number: CN218940677U
Application number: CN202223246097.3U
Authority: CN
Inventors: 张雪飞; 蓝卫; 吴亮斌
Original assignee: Hebei Aote Weili Medical Instrument Co ltd
Current assignee: Hebei Aote Weili Medical Instrument Co ltd
Priority date: 2022-12-05
Filing date: 2022-12-05
Publication date: 2023-04-28
Anticipated expiration: 2032-12-05

Abstract

The utility model relates to the technical field of ultraviolet LEDs, and provides a multi-series-parallel ultraviolet LED anti-breakdown circuit, which comprises a power supply module and an anti-breakdown LED circuit, wherein the anti-breakdown LED circuit comprises a resistor R3, a zener diode D1 and a matrix type parallel LED, a first end of the resistor R3 is connected with a power supply V+ end, a second end of the resistor R3 is connected with an anode of the matrix type parallel LED, a cathode of the matrix type parallel LED is connected with a power supply V-end, a cathode of the matrix type parallel LED is connected with an anode of the zener diode D1, and a cathode of the zener diode D1 is connected with a first end of the resistor R3. Through the technical scheme, the problem that partial ultraviolet LEDs are broken down under the condition that the voltage suddenly increases due to fluctuation of the power supply voltage in the prior art is solved.

Description

Multi-series-parallel ultraviolet LED anti-breakdown circuit

Technical Field

The utility model relates to the technical field of ultraviolet LEDs, in particular to a multi-series-parallel ultraviolet LED breakdown prevention circuit.

Background

The narrow-spectrum UVB-LEDs are used as light sources and are mostly applied to biomedical appliance phototherapy products, and a mode of connecting multiple strings of UVB-LEDs in parallel is mostly adopted to ensure that the light sources can uniformly and directly irradiate human skin. However, due to the characteristics of wavelength, light emitting angle, voltage, current, optical power and the like of the UVB-LEDs, the parallel output of the plurality of strings of UVB-LEDs has strict requirements on the design of all aspects.

In the process of using multiple strings of ultraviolet LEDs in parallel, the working state cannot be kept consistent due to the fact that the number of the ultraviolet LEDs in series is large, meanwhile, the power supply voltage fluctuates, and under the condition that the voltage suddenly increases, the problem that part of the ultraviolet LEDs are broken down exists.

Disclosure of Invention

The utility model provides a multi-series-parallel ultraviolet LED anti-breakdown circuit, which solves the problem that in the prior art, the power supply voltage fluctuates, and part of ultraviolet LEDs are broken down under the condition of sudden voltage increase.

The technical scheme of the utility model is as follows:

the multi-series-parallel ultraviolet LED breakdown prevention circuit comprises a power supply module,

the LED circuit comprises a resistor R3, a voltage stabilizing diode D1 and a matrix parallel LED, wherein a first end of the resistor R3 is connected with a power V+ end, a second end of the resistor R3 is connected with an anode of the matrix parallel LED, a cathode of the matrix parallel LED is connected with a power V-end, a cathode of the matrix parallel LED is connected with an anode of the voltage stabilizing diode D1, and a cathode of the voltage stabilizing diode D1 is connected with a first end of the resistor R3.

As a further technical scheme, the LED lamp further comprises an inductor L1, wherein a first end of the inductor L1 is connected with an anode of the zener diode D1, and a second end of the inductor L1 is connected with a cathode of the matrix parallel LED.

As a further technical scheme, the protection circuit further comprises a resistor R6, a capacitor C3, a unidirectional thyristor Q1, a zener diode D2 and a resistor R4, wherein a first end of the resistor R6 is connected with the anode of the matrix parallel LED, a second end of the resistor R6 is connected with the first end of the capacitor C3, a second end of the capacitor C3 is connected with the cathode of the matrix parallel LED, a first end of the resistor R6 is connected with the anode of the unidirectional thyristor Q1, a cathode of the unidirectional thyristor Q1 is connected with the second end of the capacitor C3, an anode of the unidirectional thyristor Q1 is connected with the cathode of the zener diode D2, an anode of the zener diode D2 is connected with the first end of the resistor R4, and a second end of the resistor R4 is connected with the gate of the unidirectional thyristor Q1.

As a further technical scheme, the protection circuit further comprises a thermistor R5 and a zener diode D3, wherein the anode of the unidirectional thyristor Q1 is connected with the first end of the thermistor R5, the second end of the thermistor R5 is connected with the cathode of the zener diode D3, and the anode of the zener diode D3 is connected with the gate of the unidirectional thyristor Q1.

As a further technical scheme, the power supply module comprises a constant-current constant-voltage driving circuit, the constant-current constant-voltage driving circuit comprises a rectifying circuit, a PWM control circuit and a constant-current constant-voltage control circuit which are sequentially connected, the PWM control circuit comprises a control chip U1, a transduction transformer B, an optocoupler U2, a resistor R8, a capacitor C5 and a diode D5, the output end of the rectifying circuit is connected with the first end of the first primary coil of the transduction transformer B, the first end of the capacitor C5 is connected with the first end of the resistor R8, the second end of the resistor R8 is connected with the cathode of the diode D5, the anode of the diode D5 is connected with the second end of the first primary coil of the transduction transformer B, the second end of the first primary coil of the transduction transformer B is connected with the output end of the control chip U1, the control end of the optocoupler U2 is connected with the emitter of the first primary coil of the optocoupler U, the output end of the second primary coil of the optocoupler U2 is connected with the second end of the second primary coil of the optocoupler B, and the anode of the second end of the second primary coil of the optocoupler B is connected with the cathode of the secondary coil of the constant-current transformer.

As a further technical scheme, the constant-current constant-voltage control circuit comprises a resistor R9, a triode Q2, a rheostat RP2, a resistor R11, a resistor R10, a change-over switch K, a resistor R12, a rheostat RP3, a controllable precise voltage stabilizing source U3, a voltage stabilizing diode D7 and a capacitor C9, wherein the first end of a secondary coil of a transduction transformer B is connected with the first end of the resistor R9, the second end of the resistor R9 is connected with an anode of an optocoupler U2 diode, a cathode of the optocoupler U2 diode is connected with a collector of the triode Q2, a base of the triode Q2 is connected with a first end of the rheostat RP2, a second end of the rheostat RP2 is grounded, a collector of the triode Q2 is connected with a cathode of the voltage stabilizing diode D7, an anode of the voltage stabilizing diode D7 is grounded, an emitter of the triode Q2 is connected with a first end of the resistor R11, an emitter of the triode Q2 is connected with a first end of the resistor R10, a second end of the triode Q2 is connected with the second end of the resistor R12, a second end of the resistor R12 is connected with the resistor R12, a second end of the rheostat is connected with the resistor R12, a second end of the resistor R12 is connected with the resistor R3, and the resistor R3 is connected with the precise voltage stabilizing source is connected with the resistor R3.

The working principle and the beneficial effects of the utility model are as follows:

in the process of switching on the power supply for irradiation of the matrix parallel LEDs, the voltage of the power supply module can fluctuate, the voltage value is negligent, and when the voltage is overlarge, the matrix parallel LEDs can be broken down, so that the LEDs are damaged; in this embodiment, the zener diode D1 is adopted, so that when the output voltage of the power module is too large, the zener diode D1 can be broken down and turned on to form a short circuit, so as to protect the matrix parallel LEDs and avoid breakdown caused by too large voltage.

Drawings

The utility model will be described in further detail with reference to the drawings and the detailed description.

FIG. 1 is a schematic diagram of an anti-breakdown LED circuit in accordance with the present utility model;

FIG. 2 is a schematic diagram of a protection circuit according to the present utility model;

fig. 3 is a schematic diagram of a constant current constant voltage driving circuit in the present utility model.

Detailed Description

The technical solutions of the embodiments of the present utility model will be clearly and completely described below in conjunction with the embodiments of the present utility model, and it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

As shown in fig. 1, the embodiment proposes a multi-series-parallel ultraviolet LED breakdown prevention circuit, which comprises a power module,

In the process of switching on the power supply for irradiation of the matrix parallel LEDs, the voltage of the power supply module can fluctuate, the voltage value is negligent, and when the voltage is overlarge, the matrix parallel LEDs can be broken down, so that the LEDs are damaged;

in this embodiment, the zener diode D1 is adopted, so that when the output voltage of the power module is too large, the zener diode D1 can be broken down and turned on to form a short circuit, so as to protect the matrix parallel LEDs and avoid breakdown caused by too large voltage.

As shown in fig. 1, the LED display device further comprises an inductor L1, wherein a first end of the inductor L1 is connected with an anode of the zener diode D1, and a second end of the inductor L1 is connected with a cathode of the matrix parallel LED.

In this embodiment, the power supply voltage of the matrix parallel LEDs may be further stabilized by the inductor L1, so as to avoid large fluctuation of the matrix parallel LEDs, and ensure the stability of the working illumination of the matrix parallel LEDs.

The protection circuit comprises a resistor R6, a capacitor C3, a unidirectional thyristor Q1, a voltage stabilizing diode D2 and a resistor R4, wherein the first end of the resistor R6 is connected with the anode of the matrix parallel LED, the second end of the resistor R6 is connected with the first end of the capacitor C3, the second end of the capacitor C3 is connected with the cathode of the matrix parallel LED, the first end of the resistor R6 is connected with the anode of the unidirectional thyristor Q1, the cathode of the unidirectional thyristor Q1 is connected with the second end of the capacitor C3, the anode of the unidirectional thyristor Q1 is connected with the cathode of the voltage stabilizing diode D2, the anode of the voltage stabilizing diode D2 is connected with the first end of the resistor R4, and the second end of the resistor R4 is connected with the gate of the unidirectional thyristor Q1.

In this embodiment, when the matrix parallel LED fails, the matrix parallel LED is in an open circuit state, and then current will flow through the zener diode D2 and the resistor R4, the zener diode D2 breaks down reversely, the gate of the unidirectional thyristor Q1 obtains a control conducting signal, and the unidirectional thyristor Q1 is turned on, so that current flows through the unidirectional thyristor Q1, and an electrical signal applied to the matrix parallel LED can be transferred in time, so that the matrix parallel LED is prevented from being electrified for a long time in a non-bright state, and an electric shock hazard caused by a human hand touching the matrix parallel LED is avoided.

The protection circuit further comprises a thermistor R5 and a zener diode D3, wherein the anode of the unidirectional thyristor Q1 is connected with the first end of the thermistor R5, the second end of the thermistor R5 is connected with the cathode of the zener diode D3, and the anode of the zener diode D3 is connected with the gate of the unidirectional thyristor Q1.

In this embodiment, the thermistor R5 senses the temperature of the matrix parallel LED in real time, if the temperature is too high in the working process of the matrix parallel LED, the resistance of the thermistor R5 decreases, the voltage division on the thermistor R5 decreases, the voltage on the zener diode D3 increases, the zener diode D3 breaks down and conducts, the gate of the unidirectional thyristor Q1 is further controlled to conduct, the unidirectional thyristor Q1 conducts, so that current flows from the unidirectional thyristor Q1 to protect the failed matrix parallel LED.

As shown in fig. 3, the power module includes a constant current and constant voltage driving circuit, the constant current and constant voltage driving circuit includes a PWM control circuit and a constant current and constant voltage control circuit that connect gradually, the PWM control circuit includes a control chip U1, a converter transformer B, an optocoupler U2, a resistor R8, a capacitor C5 and a diode D5, a first end of a first primary coil of the converter transformer B is used for connecting an output end of a rectifying circuit, a first end of the capacitor C5 is connected to a first end of the first primary coil of the converter transformer B, a first end of the capacitor C5 is connected to a first end of the resistor R8, a second end of the resistor R8 is connected to a cathode of the diode D5, an anode of the diode D5 is connected to a second end of the first primary coil of the converter transformer B, a second end of the converter transformer B is connected to an output end of the control chip U1, a control end of the converter transformer U1 is connected to an emitter of the optocoupler U2, a first end of the optocoupler U2 is connected to a second end of the converter transformer B, a second end of the diode B is connected to a second end of the cathode of the converter transformer B, and the anode of the diode is connected to a second end of the diode B is connected to a second end of the diode of the converter transformer.

In this embodiment, the control chip U1 is TOP223Y, and the constant-current and constant-voltage control circuit can control TOP223Y to be switched into a constant-current output mode and a constant-voltage output mode respectively, when the output current increases (constant-current output mode) or the output voltage increases (constant-voltage output mode), the conduction of the optocoupler U2 is enhanced, the input current at the control end of the control chip U1 increases, and the duty ratio of the output voltage pulse of the control chip U1 decreases, so that the output current of the circuit decreases (constant-current mode) or the output voltage decreases (constant-voltage mode); similarly, when the output current of the circuit is reduced (constant current mode) or the output voltage is reduced (constant voltage mode), the control of the optocoupler U2 on the control chip U1 increases the duty ratio of the output voltage pulse, so that the output current of the circuit is increased (constant current mode) or the output voltage of the circuit is increased (constant voltage mode), the constant output current of the circuit (constant current mode) or the constant output voltage of the circuit (constant voltage mode) is finally realized, and the light emitting stability of the matrix parallel LEDs is ensured.

As shown in fig. 3, the constant-current and constant-voltage control circuit includes a resistor R9, a triode Q2, a varistor RP2, a resistor R11, a resistor R10, a switch K, a resistor R12, a varistor RP3, a controllable precision voltage regulator source U3, a voltage regulator diode D7, and a capacitor C9, wherein a first end of a secondary winding of the transduction transformer B is connected to the first end of the resistor R9, a second end of the resistor R9 is connected to an anode of the optocoupler U2 diode, a cathode of the optocoupler U2 diode is connected to a collector of the triode Q2, a base of the triode Q2 is connected to a first end of the varistor RP2, a second end of the varistor RP2 is grounded, a collector of the triode Q2 is connected to a cathode of the diode D7, an anode of the diode D7 is grounded, an emitter of the triode Q2 is connected to a first end of the resistor R11, an emitter of the triode Q2 is connected to a first end of the resistor R10, a second end of the triode Q10 is connected to the second end of the resistor R12, a second end of the resistor Q12 is connected to the second end of the resistor R12, a resistor Q12 is connected to the second end of the resistor Q2, and the resistor Q12 is connected to the second end of the resistor Q12.

In this embodiment, the controllable precise voltage-stabilizing source U3 is TL431, when the switch K is switched to the second selection end (2 pins), the circuit is in a constant current output mode, the anode and the control electrode of the controllable precise voltage-stabilizing source U3 are shorted, the controllable precise voltage-stabilizing source U3 is in a cut-off state, and the constant voltage control circuit is in a cut-off state.

The constant current control circuit is composed of a triode Q2 and a resistor R10 and is used for keeping the output current constant. The method comprises the following steps: when the output current is increased, the voltage at two ends of the current is increased by flowing through the resistor R10, and then the current is amplified by the triode Q2, the collector current of the triode Q2, namely the current flowing through the diode of the optocoupler U2, is increased, the conduction of the optocoupler U2 is enhanced, the triode current of the optocoupler U2 is enhanced, namely the input current at the control end of the control chip U1 is increased, the duty ratio of the output voltage pulse of the control chip U1 is reduced, and the output current of the circuit is reduced; when the output current decreases, the control process of the circuit is reversed from that described above.

By adjusting the varistor RP2, a constant value of the output current can be adjusted.

When the change-over switch K is switched to a first selection end (1 pin), the circuit is in a constant voltage output mode, at the moment, the resistance value of the resistor R11 and the resistor R10 connected in parallel is smaller, when the output current is smaller, the triode Q2 is in a cut-off state, the constant voltage control circuit is composed of a controllable precise voltage stabilizing source U3, a resistor R12 and a rheostat RP3, the output voltage is regulated through the rheostat RP3, when the output voltage is increased, the output voltage is divided by the resistor R12 and the rheostat RP3, the voltage separated from the two ends of the resistor R12 is also increased, the current flowing through the diode U2 is increased through the control of the controllable precise voltage stabilizing source U3, meanwhile, the duty ratio of the output voltage pulse of the control chip U1 is reduced, and the output current of the circuit is reduced; when the output voltage decreases, the control process of the circuit is reversed from that described above. Through the control process, the output voltage can be kept stable, and finally the constant-voltage output of the driving circuit is realized.

The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the utility model.

Claims

1. The multi-series-parallel ultraviolet LED breakdown prevention circuit comprises a power supply module,

the LED lamp is characterized by further comprising an anti-breakdown LED circuit, wherein the anti-breakdown LED circuit comprises a resistor R3, a zener diode D1 and a matrix type parallel LED, a first end of the resistor R3 is connected with a power supply V+ end, a second end of the resistor R3 is connected with an anode of the matrix type parallel LED, a cathode of the matrix type parallel LED is connected with a power supply V-end, a cathode of the matrix type parallel LED is connected with an anode of the zener diode D1, and a cathode of the zener diode D1 is connected with a first end of the resistor R3.

2. The multi-series-parallel ultraviolet LED breakdown preventing circuit according to claim 1, further comprising an inductor L1, wherein a first end of the inductor L1 is connected to an anode of the zener diode D1, and a second end of the inductor L1 is connected to a cathode of the matrix-type parallel LED.

3. The multi-series-parallel ultraviolet LED breakdown preventing circuit according to claim 2, further comprising a protection circuit, wherein the protection circuit comprises a resistor R6, a capacitor C3, a unidirectional thyristor Q1, a zener diode D2 and a resistor R4, a first end of the resistor R6 is connected with the anode of the matrix parallel LED, a second end of the resistor R6 is connected with the first end of the capacitor C3, a second end of the capacitor C3 is connected with the cathode of the matrix parallel LED, a first end of the resistor R6 is connected with the anode of the unidirectional thyristor Q1, the cathode of the unidirectional thyristor Q1 is connected with the second end of the capacitor C3, the anode of the unidirectional thyristor Q1 is connected with the cathode of the zener diode D2, the anode of the zener diode D2 is connected with the first end of the resistor R4, and a second end of the resistor R4 is connected with the gate of the unidirectional thyristor Q1.

4. The multi-series-parallel ultraviolet LED breakdown preventing circuit according to claim 3, wherein the protection circuit further comprises a thermistor R5 and a zener diode D3, the anode of the unidirectional thyristor Q1 is connected to the first end of the thermistor R5, the second end of the thermistor R5 is connected to the cathode of the zener diode D3, and the anode of the zener diode D3 is connected to the gate of the unidirectional thyristor Q1.

5. The multi-series-parallel ultraviolet LED breakdown prevention circuit according to any one of claims 1 to 4, wherein the power module comprises a constant-current constant-voltage driving circuit, the constant-current constant-voltage driving circuit comprises a PWM control circuit and a constant-current constant-voltage control circuit which are sequentially connected, the PWM control circuit comprises a control chip U1, a transduction transformer B, an optocoupler U2, a resistor R8, a capacitor C5 and a diode D5, a first end of a first primary coil of the transduction transformer B is used for connecting an output end of a rectifying circuit, a first end of the capacitor C5 is connected with a first end of a first primary coil of the transduction transformer B, a first end of the capacitor C5 is connected with a first end of the resistor R8, a second end of the resistor R8 is connected with a cathode of the diode D5, an anode of the diode D5 is connected with a second end of a first primary coil of the transduction transformer B, a second end of the first primary coil of the transduction transformer B is connected with an output end of the control chip U1, a first end of the first primary coil of the transduction transformer B is connected with a second end of the optocoupler U2, a second end of the optocoupler B is connected with a second end of the optocoupler B, and the anode of the diode D2 is connected with a second end of the diode D is connected with a second end of the second primary coil of the diode.

6. The multi-series-parallel ultraviolet LED breakdown prevention circuit according to claim 5, wherein the constant current and constant voltage control circuit comprises a resistor R9, a triode Q2, a rheostat RP2, a resistor R11, a resistor R10, a switching switch K, a resistor R12, a rheostat RP3, a controllable precision zener diode D3, a zener diode D7 and a capacitor C9, a first end of a secondary winding of the transducing transformer B is connected to a first end of the resistor R9, a second end of the resistor R9 is connected to an anode of the optocoupler U2 diode, a cathode of the optocoupler U2 diode is connected to a collector of the triode Q2, a base of the triode Q2 is connected to a first end of the rheostat RP2, a second end of the rheostat RP2 is grounded, an emitter of the triode Q2 is connected to a first end of the resistor R11, a first end of the triode Q2 is connected to the first end of the resistor R10, a second end of the resistor R12 is connected to the second end of the resistor R12, a second end of the resistor Q2 is connected to the precision zener diode Q12, a second end of the resistor Q2 is grounded, a second end of the resistor Q2 is connected to the second end of the resistor R12 is connected to the precision resistor R12, and a second end of the resistor is grounded.