CN211406345U

CN211406345U - LED drive power supply open-circuit protection circuit compatible with inductive ballast

Info

Publication number: CN211406345U
Application number: CN201922264750.0U
Authority: CN
Inventors: 刘中林; 张伦
Original assignee: Suzhou Qixiang Electronic Technology Co ltd
Current assignee: Suzhou Qixiang Electronic Technology Co ltd
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2020-09-01
Anticipated expiration: 2029-12-17

Abstract

The utility model discloses a compatible inductive ballast LED drive power supply open-circuit protection circuit, which comprises an AC power switch circuit for short-circuiting the AC voltage output by the inductive ballast; an open circuit protection circuit for preventing damage to the circuit board when the load is open; the voltage rectifying and filtering circuit is used for converting alternating-current voltage into direct-current voltage; the current sampling comparison circuit is used for collecting load current and comparing the load current with a set value; the control pulse generating circuit is used for generating corresponding driving pulses to the alternating current power switching circuit; alternating current power switch circuit, overvoltage crowbar, voltage rectification filter circuit, current sampling comparison circuit and control pulse generating circuit connect gradually, the beneficial effects of the utility model are that: 1. the realization cost is low: only 2 low-power TVS tubes are needed; 2. and (3) working stability: because when the TVS works normally, the TVS tube is not conducted, and the performance change can not occur due to long service time.

Description

LED drive power supply open-circuit protection circuit compatible with inductive ballast

Technical Field

The utility model relates to a LED technical field specifically is a compatible inductive ballast's LED drive power supply open circuit protection circuit.

Background

When an LED is tested or used, due to some reason, when the load of the LED lamp strip is open, the constant current circuit outputs voltage which is two times higher than the normal use voltage of the filter electrolytic capacitor, the capacitor explodes, even fires, and the circuit is damaged greatly.

If the withstand voltage of the electrolytic capacitor is increased, the production cost is very high, and the space inside the lamp is limited, so that the scheme using the voltage twice higher than the normal operating voltage is difficult to realize.

Against this background, there is a need for a solution that can not only use a conventional electrolytic capacitor, but also prevent the electrolytic capacitor from being damaged by explosion due to overvoltage when the load is open, and the present invention is a research and development effort to solve the problem.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a compatible inductive ballast's LED drive power supply open circuit protection circuit to solve the problem that proposes in the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme:

an LED driving power supply open-circuit protection circuit compatible with an inductive ballast comprises an alternating current power switch circuit for short-circuiting alternating current voltage output by the inductive ballast; an open circuit protection circuit for preventing damage to the circuit board when the load is open; the voltage rectifying and filtering circuit is used for converting alternating-current voltage into direct-current voltage; the current sampling comparison circuit is used for collecting load current and comparing the load current with a set value; the control pulse generating circuit is used for generating corresponding driving pulses to the alternating current power switching circuit; the alternating current power switch circuit, the overvoltage protection circuit, the voltage rectification filter circuit, the current sampling comparison circuit and the control pulse generating circuit are sequentially connected.

As a further aspect of the present invention: the alternating current power switching circuit comprises a switching tube SCR1 and a switching tube SCR2, wherein a voltage monitoring device TVS tube TVS1 is connected between the anode and the control electrode of the switching tube SCR 1; a voltage monitoring device TVS tube TVS2 is connected between the anode and the control electrode of the switching tube SCR 2.

As a further aspect of the present invention: the voltage rectifying and filtering circuit selects a bridge rectifying circuit U2 and a capacitor CX 1.

As a further aspect of the present invention: the current sampling comparison circuit comprises a resistor R2, a resistor R4, a resistor R7 and a resistor R8.

As a further aspect of the present invention: the control pulse generating circuit comprises a resistor R1, a resistor R3 and a capacitor C1.

Compared with the prior art, the beneficial effects of the utility model are that: 1. the realization cost is low: only 2 low-power TVS tubes are needed; 2. and (3) working stability: because when the TVS works normally, the TVS tube is not conducted, and the performance change can not occur due to long service time.

Drawings

Fig. 1 is a circuit diagram of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Example 1: referring to fig. 1, in an embodiment of the present invention, an LED driving power supply open-circuit protection circuit compatible with an inductive ballast includes an ac power switching circuit for short-circuiting an ac voltage output by the inductive ballast; an open circuit protection circuit for preventing damage to the circuit board when the load is open; the voltage rectifying and filtering circuit is used for converting alternating-current voltage into direct-current voltage; the current sampling comparison circuit is used for collecting load current and comparing the load current with a set value; the control pulse generating circuit is used for generating corresponding driving pulses to the alternating current power switching circuit; the alternating current power switch circuit, the overvoltage protection circuit, the voltage rectification filter circuit, the current sampling comparison circuit and the control pulse generating circuit are sequentially connected. The alternating current power switching circuit comprises a switching tube SCR1 and a switching tube SCR2, and a voltage monitoring device TVS tube TVS1 is connected between the anode and the control electrode of the switching tube SCR 1; a voltage monitoring device TVS tube TVS2 is connected between the anode and the control electrode of the switching tube SCR 2. The voltage rectifying and filtering circuit selects a bridge rectifying circuit U2 and a capacitor CX 1. The current sampling comparison circuit comprises a resistor R2, a resistor R4, a resistor R7 and a resistor R8. The control pulse generating circuit comprises a resistor R1, a resistor R3 and a capacitor C1. The TVS tube is connected to the control alternating current power switch circuit, so that when the main control circuit stops outputting trigger pulses, the trigger pulses can be automatically generated to regulate energy output transmitted to an LED load, the condition that the output voltage is too high to damage a filter electrolytic capacitor is limited, and the withstand voltage values of the TVS1 and the TVS2 are slightly higher than the normal working voltage in design, so that after the output voltage rises to the voltage threshold value, the TVS1 and the TVS2 are conducted due to overvoltage to output trigger signals to control an alternating current switch consisting of a silicon controlled rectifier, and the aim of regulating the output voltage is fulfilled; the control overvoltage protection device has the advantages of stable and reliable work, simple peripheral circuit and the like, and can enable the whole lamp to have high price advantage.

Example 2: on the basis of embodiment 1, the voltage rectifying and filtering circuit may also be composed of an integrated rectifier chip and a filter chip.

It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. An LED driving power supply open-circuit protection circuit compatible with an inductive ballast is characterized by comprising an alternating current power switch circuit for short-circuiting alternating current voltage output by the inductive ballast; an open circuit protection circuit for preventing damage to the circuit board when the load is open; the voltage rectifying and filtering circuit is used for converting alternating-current voltage into direct-current voltage; the current sampling comparison circuit is used for collecting load current and comparing the load current with a set value; the control pulse generating circuit is used for generating corresponding driving pulses to the alternating current power switching circuit; the alternating current power switch circuit, the overvoltage protection circuit, the voltage rectification filter circuit, the current sampling comparison circuit and the control pulse generating circuit are sequentially connected.

2. The LED driving power supply open-circuit protection circuit compatible with the inductive ballast as recited in claim 1, wherein the AC power switch circuit comprises a switching tube SCR1 and a switching tube SCR2, and a voltage monitoring device TVS tube TVS1 is connected between an anode and a control electrode of the switching tube SCR 1; a voltage monitoring device TVS tube TVS2 is connected between the anode and the control electrode of the switching tube SCR 2.

3. The LED driving power supply open-circuit protection circuit compatible with the inductive ballast as claimed in claim 2, wherein the voltage rectifying and filtering circuit is a bridge rectifier circuit U2 and a capacitor CX 1.

4. The LED driving power supply open-circuit protection circuit compatible with the inductive ballast as recited in claim 1, wherein the current sampling comparison circuit comprises a resistor R2, a resistor R4, a resistor R7 and a resistor R8.

5. The LED driving power supply open-circuit protection circuit compatible with the inductive ballast as recited in claim 3, wherein the control pulse generating circuit comprises a resistor R1, a resistor R3 and a capacitor C1.