CN218974551U

CN218974551U - Fault detection circuit for output voltage signal of switching power supply and switching power supply

Info

Publication number: CN218974551U
Application number: CN202223249006.1U
Authority: CN
Inventors: 王童童; 雍煜杰; 张鹏
Original assignee: Glorymv Electronics Co ltd
Current assignee: Glorymv Electronics Co ltd
Priority date: 2022-12-05
Filing date: 2022-12-05
Publication date: 2023-05-05
Anticipated expiration: 2032-12-05

Abstract

The utility model discloses a fault detection circuit for outputting a voltage signal of a switching power supply, which comprises a comparator circuit, an optocoupler N2 and diodes V1, V2 and V3, wherein the input end of the comparator circuit is respectively connected to a reference voltage circuit and the voltage output end of the switching power supply; the output end of the comparator circuit is connected to the cathode of the diode V1, the anode of the diode V1 is connected to the anode of the diode V2, the cathode of the diode V2 is connected to the anode of the optocoupler input end, and the cathode of the optocoupler input end is led out of the NORMAL terminal; the collector electrode of the output end of the optical coupler is connected to the anode of the diode V3; the collector electrode of the output end of the optocoupler is connected to the positive electrode of the power supply through a resistor R6; the collector electrode of the output end of the optical coupler is connected to the emitter electrode of the output end of the optical coupler through a capacitor C3, and the emitter electrode of the output end of the optical coupler is grounded; a FAULT terminal is led out from the cathode of the diode V3; the anode of the diode V1 is connected to the positive electrode of the power supply through a resistor R5; the NORMAL terminal, FAULT terminal outputs a voltage signal indicative of a FAULT condition of the output voltage of the switching power supply.

Description

Fault detection circuit for output voltage signal of switching power supply and switching power supply

Technical Field

The utility model relates to the field of detection of switching power supplies, in particular to a fault detection circuit of a switching power supply output voltage signal and a switching power supply.

Background

Along with the continuous innovation of the technology, the application prospect of the switching power supply is wider and wider, and the switching power supply is an indispensable part of the rapid development of the electronic information industry at present. As a way of stabilizing the output voltage, the stability of the output voltage is an important index, so in the prior art, how to adjust the output of the switching power supply to be more stable and reliable is often considered, and the output is kept at a set voltage value to meet the output requirement.

For example, patent application No. 202110410089.9 discloses a switching power supply and an output voltage compensation circuit thereof, which compensates the output of the switching power supply from the angle of voltage compensation, so as to ensure the stable and reliable output of the switching power supply, but mainly controls the output of the switching power supply in a regulating manner, but under certain fault conditions, the output of the switching power supply is still abnormal, for example, the output voltage is lower than the set voltage to a certain extent, which corresponds to the fault of the switching power supply, the fault of the switching power supply leads to the reduction or zero of the output voltage, the components are damaged lightly, and the whole switching power supply and the load thereof are in dangerous states, so that the fault state of the output voltage of the switching power supply also needs to be detected.

Most of the existing detection schemes are based on a mode of directly measuring the voltage output, detection is often not timely enough in actual use, intuitiveness is lacking, the detected voltage output is still required to be processed by a data processing unit to judge whether a fault exists, a control chip is required to be additionally added, and fault detection is often not timely and high in cost. Therefore, it is required to detect the voltage output state of the switching power supply in real time by a simple circuit.

Disclosure of Invention

The utility model aims to overcome the defects of the prior art, and provides a fault detection circuit of a switching power supply output voltage signal and a switching power supply, which are used for detecting the fault state of the switching power supply output voltage by adopting a simple circuit so as to solve the defects of the prior art that the fault detection is carried out by detecting the voltage output.

In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows: the fault detection circuit for outputting voltage signals of the switching power supply comprises a comparator circuit, an optocoupler N2, diodes V1, V2 and V3, wherein the input end of the comparator circuit is respectively connected to the reference voltage circuit and the voltage output end of the switching power supply; the output end of the comparator circuit is connected to the cathode of the diode V1, the anode of the diode V1 is connected to the anode of the diode V2, the cathode of the diode V2 is connected to the anode of the optocoupler input end, and the cathode of the optocoupler input end is led out of the NORMAL terminal; the collector electrode of the output end of the optical coupler is connected to the anode of the diode V3; the collector electrode of the output end of the optocoupler is connected to the positive electrode of the power supply through a resistor R6; the collector electrode of the output end of the optical coupler is connected to the emitter electrode of the output end of the optical coupler through a capacitor C3, and the emitter electrode of the output end of the optical coupler is grounded; a FAULT terminal is led out from the cathode of the diode V3; the anode of the diode V1 is connected to the positive electrode of the power supply through a resistor R5; the NORMAL terminal, FAULT terminal outputs a voltage signal indicative of a FAULT condition of the output voltage of the switching power supply.

The comparator circuit comprises a comparator N1, wherein the non-inverting input end of the comparator N1 is connected to the voltage output end of the switching power supply through a resistor R2; the non-inverting input end of the comparator N1 is grounded through a resistor R2; the inverting input end of the comparator N1 is connected to the reference voltage circuit; the output of the comparator N1 is connected to the cathode of the diode V1.

The reference voltage circuit comprises resistors R3 and R4 and a capacitor C2, and the positive electrode of the power supply is grounded after sequentially passing through the resistors R3 and R4 which are connected in series; the lead-out terminal between the resistors R3 and R4 connected in series is connected to the inverting input end of the comparator N1, and the capacitor C2 is arranged at two ends of the resistor R4 in parallel.

The FAULT terminal is connected to a FAULT indicator.

The NORMAL terminal is connected to a NORMAL indicator light.

A switching power supply adopts a fault detection circuit of a switching power supply output voltage signal to carry out fault detection on output voltage.

The utility model has the advantages that: whether the output voltage of the switching power supply is obviously abnormal or not can be detected rapidly and accurately, and a level signal representing faults can be output rapidly and timely, so that the fault state of the output voltage of the switching power supply can be obtained conveniently and timely, the power supply fault can be responded conveniently and timely, and the power supply is more reliable and safer; the fault signals can be output by adopting components such as a comparator, a diode, a resistor and the like, and a processor chip is not used, so that the detection is more accurate and rapid, the cost is low, the output high-low level signals can directly represent the fault state of the switching power supply, and the fault state of the switching power supply can be rapidly known based on the high-low level signals; and the LEDs with different colors can be driven based on the high and low levels, so that the fault state can be more clearly and obviously known.

Drawings

The contents of the drawings and the marks in the drawings of the present specification are briefly described as follows:

fig. 1 is a schematic diagram of a fault detection circuit for a switching power supply output voltage signal according to the present utility model.

Detailed Description

The following detailed description of the utility model refers to the accompanying drawings, which illustrate preferred embodiments of the utility model in further detail.

The utility model provides a voltage signal detection circuit, which utilizes a comparator to collect and compare voltage signals, and then generates normal or fault results through the processing of an optical coupler TLP521-1 so as to achieve the detection effect. Taking a voltage output signal collected by a switching power supply as an example, when the collected voltage output signal is too low or zero, a FAULT end behind an optical coupler outputs a high level, and NORMAL outputs a low level, and the voltage signal is in FAULT; the reverse voltage signal is normal. The specific circuit is as follows:

as shown in fig. 1, the fault detection circuit for outputting a voltage signal by a switching power supply comprises a comparator circuit, an optocoupler N2 and diodes V1, V2 and V3, wherein the input end of the comparator circuit is respectively connected to a reference voltage circuit and the voltage output end of the switching power supply; the output end of the comparator circuit is connected to the cathode of the diode V1, the anode of the diode V1 is connected to the anode of the diode V2, the cathode of the diode V2 is connected to the anode of the optocoupler input end, and the cathode of the optocoupler input end is led out of the NORMAL terminal; the collector electrode of the output end of the optical coupler is connected to the anode of the diode V3; the collector electrode of the output end of the optocoupler is connected to the positive electrode of the power supply through a resistor R6; the collector electrode of the output end of the optical coupler is connected to the emitter electrode of the output end of the optical coupler through a capacitor C3, and the emitter electrode of the output end of the optical coupler is grounded; a FAULT terminal is led out from the cathode of the diode V3; the anode of the diode V1 is connected to the positive electrode of the power supply through a resistor R5; the NORMAL terminal, FAULT terminal outputs a voltage signal indicative of a FAULT condition of the output voltage of the switching power supply. The optocoupler uses a TLP521-1 optocoupler.

The comparator circuit comprises a comparator N1, wherein the non-inverting input end of the comparator N1 is connected to the voltage output end of the switching power supply through a resistor R2; the non-inverting input end of the comparator N1 is grounded through a resistor R2; the inverting input end of the comparator N1 is connected to the reference voltage circuit; the output of the comparator N1 is connected to the cathode of the diode V1. The reference voltage circuit comprises resistors R3 and R4 and a capacitor C2, and the positive electrode of the power supply is grounded after sequentially passing through the resistors R3 and R4 which are connected in series; the lead-out terminal between the resistors R3 and R4 connected in series is connected to the inverting input end of the comparator N1, and the capacitor C2 is arranged at two ends of the resistor R4 in parallel.

The working principle is as follows:

the output voltage of the switching power supply is sent to a voltage dividing circuit formed by R1 and R2 through an output end OUT+ of the switching power supply, the voltage divided by R1 and R2 is sent to a non-inverting input end of a comparator N1, and a capacitor C1 plays roles in filtering and voltage stabilization; the reference voltage generating circuit uses +5V power supply, the +5V power supply divides the voltage through R3 and R4 to obtain reference voltage, the reference voltage is sent to the inverting input end of the comparator N1, and the voltage input to N1 is filtered by C2. The comparator N1 compares the output voltage of the switching power supply with the reference voltage, when the switching power supply fails, the voltage at the output end of the switching power supply is too low or 0, the comparator N1 outputs a low level, so that the +12V power supply is conducted to V1, the +12V power supply is conducted through an anode of R5V1 and a cathode of V1, and V2 is not conducted, thus NO voltage flows on the input side of the optocoupler, the output of the NO RMAL terminal is a low level, the triode on the output side of the optocoupler is cut off, the diode V3 is conducted by the 12V power supply on the output side of the optocoupler, and at the moment, the FAULT terminal outputs a high level, and whether the switching power supply fails can be directly judged through high-low level signals output by the FAULT terminal and the NORMAL terminal; similarly, when the switching power supply is normal, the switching power supply outputs normal voltage, the output end of the N1 is at a high level at the moment, the high level can cause the non-conduction of the V1, and the 12V power supply is conducted through the R5 and the V2 at the moment; the output of the NORMA L terminal is high level, the triode at the output side is conducted, the power supply at the output side is grounded after passing through the resistor R6 and the collector and the emitter of the triode at the output side, the diode V3 is short-circuited and can not be conducted, and the low voltage is output by the FAULT terminal. Thus, the fault state can be quickly acquired according to the high-low level of the two terminals.

In a preferred embodiment, the present application implements an indication of failure or not by means of a light emitting diode, the FAULT terminal being connected to the red light emitting diode; the NORMAL terminal is connected to the green light emitting diode. Thus, when a FAULT occurs, the FAULT terminal to which the positive electrode of the red light emitting diode is connected is high voltage, so that the light emitting diode is turned on to emit red light. And in the same way, when the signal is obtained, the green light-emitting diode emits light, so that the fault of the switching power supply can be rapidly realized, and the protection action and the like can be rapidly performed after the signal is obtained.

The application also provides a switching power supply, and the switching power supply adopts the fault detection circuit of the switching power supply output voltage signal to carry out fault detection on the output voltage.

Firstly, setting a voltage reference on the 2 end of a comparator N1 according to requirements; OUT+ is the voltage output signal that switching power supply gathered, and when switching power supply voltage output was too low or be zero, the 3 end of comparator N1 output a low level, and diode V1 switched on this moment, diode V2 and opto-coupler N2 can't switch on, and NORMAL end output low level, because opto-coupler N2 is non-conductive, so diode V3 switches on the FAULT end output high level, detects the FAULT signal promptly.

In contrast, when the output of the switching power supply is NORMAL, the 3 terminal of N1 outputs a high level, at this time, the diode V1 is not turned on, the diode V2 and the optocoupler N2 are turned on, the NORMAL terminal outputs a high level, and since the optocoupler N2 is turned on, +12v is directly pulled down through the optocoupler ground, the diode V3 cannot be turned on to the FAULT terminal to output a low level, i.e., at this time, the voltage output of the switching power supply is NORMAL.

Through the two processes, whether the voltage output of the switching power supply is normal or not can be timely detected, two ends of the FAULTD, NORMAL light-emitting diode can be directly connected with the red light-emitting diode and the green light-emitting diode respectively in actual use, so that the detection result is more visual, and meanwhile, different references can be set at the 2 end of the comparator N1 according to the output index requirements of the switching power supplies of different types, so that the voltage signal detection result is achieved.

It is obvious that the specific implementation of the present utility model is not limited by the above-mentioned modes, and that it is within the scope of protection of the present utility model only to adopt various insubstantial modifications made by the method conception and technical scheme of the present utility model.

Claims

1. The fault detection circuit of the output voltage signal of the switching power supply is characterized in that: the voltage detection circuit comprises a comparator circuit, an optocoupler N2, diodes V1, V2 and V3, wherein the input end of the comparator circuit is respectively connected to a reference voltage circuit and the voltage output end of a switching power supply; the output end of the comparator circuit is connected to the cathode of the diode V1, the anode of the diode V1 is connected to the anode of the diode V2, the cathode of the diode V2 is connected to the anode of the optocoupler input end, and the cathode of the optocoupler input end is led out of the NORMAL terminal; the collector electrode of the output end of the optical coupler is connected to the anode of the diode V3; the collector electrode of the output end of the optocoupler is connected to the positive electrode of the power supply through a resistor R6; the collector electrode of the output end of the optical coupler is connected to the emitter electrode of the output end of the optical coupler through a capacitor C3, and the emitter electrode of the output end of the optical coupler is grounded; a FAULT terminal is led out from the cathode of the diode V3; the anode of the diode V1 is connected to the positive electrode of the power supply through a resistor R5; the NORMAL terminal, FAULT terminal outputs a voltage signal indicative of a FAULT condition of the output voltage of the switching power supply.

2. The fault detection circuit of a switching power supply output voltage signal as claimed in claim 1, wherein: the comparator circuit comprises a comparator N1, wherein the non-inverting input end of the comparator N1 is connected to the voltage output end of the switching power supply through a resistor R2; the non-inverting input end of the comparator N1 is grounded through a resistor R2; the inverting input end of the comparator N1 is connected to the reference voltage circuit; the output of the comparator N1 is connected to the cathode of the diode V1.

3. A fault detection circuit for a switching power supply output voltage signal as claimed in claim 1 or claim 2, wherein: the reference voltage circuit comprises resistors R3 and R4 and a capacitor C2, and the positive electrode of the power supply is grounded after sequentially passing through the resistors R3 and R4 which are connected in series; the lead-out terminal between the resistors R3 and R4 connected in series is connected to the inverting input end of the comparator N1, and the capacitor C2 is arranged at two ends of the resistor R4 in parallel.

4. A fault detection circuit for a switching power supply output voltage signal as claimed in claim 1 or claim 2, wherein: the FAULT terminal is connected to a FAULT indicator.

5. A fault detection circuit for a switching power supply output voltage signal as claimed in claim 1 or claim 2, wherein: the NORMAL terminal is connected to a NORMAL indicator light.

6. A switching power supply, characterized by: the switching power supply adopts the fault detection circuit for the output voltage signal of the switching power supply according to any one of claims 1 to 5.