Over-temperature protection circuit of switching power supply transformer

Abstract

The utility model discloses an over-temperature protection circuit for a switching power supply transformer, which comprises a temperature acquisition module, an over-temperature protection module and an auxiliary power supply module which are arranged on the transformer, and the output end of the auxiliary power supply module is respectively connected with the power supply input ends of the temperature acquisition module and the over-temperature protection module. The output end of the temperature acquisition module is connected with the input end of the over-temperature protection module, and the output end of the over-temperature protection module is connected with the input end of the switching power supply main control chip; the output end of the over-temperature protection circuit is connected with a display used for displaying over-temperature alarm information. The temperature acquisition module and the transformer are integrated together to acquire the temperature of the transformer, when the temperature acquisition module detects that the temperature of the transformer reaches the set maximum temperature, the temperature acquisition module outputs a high-level signal to the over-temperature protection module, and the over-temperature protection module outputs a low-level state signal to the outside after receiving the high-level signal. And the module stops working, so that the effect of protecting the transformer is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of switching power supplies, and more specifically to an over-temperature protection circuit for a switching power supply transformer. Background Art

[0002] At present, temperature protection function is usually not adopted for switching power supply transformers. The cooling fan is used to cool down all components inside the module. Under normal circumstances, the heat generated and dissipated by the transformer will reach a balance. At this time, the transformer temperature will not rise any further and reach a stable and safe temperature. However, if the switching power supply works under overload for a long time, the heat balance of the transformer will be broken, the transformer temperature will rise rapidly, and eventually cause thermal damage to the transformer. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a switching power supply transformer over-temperature protection circuit, which can monitor the transformer temperature in real time and avoid thermal damage to the transformer due to excessive temperature.

[0004] In order to solve the above technical problems, the technical solutions adopted by the present utility model are as follows.

[0005] A switching power supply transformer over-temperature protection circuit comprises a temperature acquisition module arranged on the transformer for acquiring transformer temperature, an over-temperature protection module for issuing an over-temperature protection signal, and an auxiliary power supply module for providing power, wherein the output end of the auxiliary power supply module is respectively connected to the power input ends of the temperature acquisition module and the over-temperature protection module, the output end of the temperature acquisition module is connected to the input end of the over-temperature protection module, and the output end of the over-temperature protection module is connected to the input end of the switching power supply main control chip; the output end of the over-temperature protection circuit is connected to a display for displaying over-temperature alarm information.

[0006] To further optimize the technical solution, the auxiliary power supply module and the temperature acquisition module are connected via a twisted pair cable, the auxiliary power supply module and the over-temperature protection module are connected via circuit board routing, and the temperature acquisition module and the over-temperature protection module are connected via flying wires.

[0007] To further optimize the technical solution, the temperature acquisition module is arranged on the outer layer of the secondary end coil of the transformer, and includes a sampling resistor connected in series for collecting temperature information and a temperature switch for controlling whether to connect the over-temperature protection circuit. The sampling resistor and the temperature switch are connected in series, one end is connected to the auxiliary power supply module, and the other end is connected to the over-temperature protection circuit.

[0008] To further optimize the technical solution, the over-temperature protection module includes an over-temperature display circuit for displaying over-temperature information, a protection circuit for outputting a protection signal, and a fault output circuit for outputting fault information. The input ends of the over-temperature display circuit, the protection circuit, and the fault output circuit are connected to the output end of the temperature acquisition module, the output end of the over-temperature display module is connected to the input end of the display, the protection circuit is connected to the control end of the main control chip of the switching power supply, and the output end of the fault output circuit is connected to the fault output end of the main control chip.

[0009] To further optimize the technical solution, the over-temperature display circuit includes a capacitor C48 and a diode V42, one end of the capacitor C48 is connected to the output end of the temperature acquisition module, the other end of the capacitor C48 is grounded, the cathode of the diode V42 is connected to the output end of the temperature acquisition module, and the anode of the diode V42 is connected to the display.

[0010] To further optimize the technical solution, the protection circuit includes a diode V06, a current limiting resistor R42, and a transistor V13 which are connected in series at the output end of the temperature acquisition module. The collector of the transistor is connected to the control end of the switching power supply main control chip through a diode V60. The positive electrode of the diode V06 is connected to the output end of the temperature acquisition module. The negative electrode of the diode V06 is connected to the base of the transistor V13 through the current limiting resistor R42. The emitter of the transistor V13 is connected to the ground through a resistor R26.

[0011] To further optimize the technical solution, the fault output circuit includes a diode V70 and a current limiting resistor R71 connected to the negative output end of the diode V06, the other end of the current limiting resistor R71 is connected to the fault output end of the main control chip, the positive electrode of the diode V70 is connected to the negative electrode of the diode V06, and the negative electrode of the diode V70 is connected to the current limiting resistor R71.

[0012] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.

[0013] The utility model provides a switching power supply transformer over-temperature protection circuit, which integrates a temperature acquisition module and a transformer together to accurately acquire the temperature of the transformer in real time. When the temperature acquisition module detects that the transformer temperature reaches a set maximum temperature, it outputs a high-level signal to the over-temperature protection module. After receiving the high-level signal, the over-temperature protection module outputs a low-level state signal to the outside, so that the module stops working, thereby achieving the function of protecting the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural block diagram of the utility model;

[0015] Figure 2 The position of the temperature acquisition module of the utility model in the transformer;

[0016] Figure 3 This is a circuit diagram of the over-temperature protection module described in the utility model.

[0017] Among them: 1. Transformer secondary coil, 2. Temperature acquisition module. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] A switching power supply transformer over-temperature protection circuit, combined with Figure 1 As shown, it includes a temperature acquisition module, an over-temperature protection module and an auxiliary power supply module. The temperature acquisition module is arranged on the transformer to acquire the transformer temperature. The over-temperature protection module is used to send an over-temperature protection signal. The auxiliary power supply module is used to provide power. The output end of the auxiliary power supply module is respectively connected to the power input end of the temperature acquisition module and the over-temperature protection module. The output end of the temperature acquisition module is connected to the input end of the over-temperature protection module. The output end of the over-temperature protection module is connected to the input end of the switching power supply main control chip. The output end of the over-temperature protection circuit is connected to a display to display over-temperature alarm information.

[0020] The auxiliary power module and the temperature acquisition module are connected through a twisted pair cable, the auxiliary power module and the over-temperature protection module are connected through circuit board routing, and the temperature acquisition module and the over-temperature protection module are connected through flying wires.

[0021] The position of the temperature acquisition module 2 in the transformer is as follows: Figure 2 As shown, the temperature acquisition module 2 is arranged on the outer layer of the transformer secondary end coil 1. When the transformer manufacturer produces the transformer, it is fixed to the outermost layer of the transformer secondary end coil 1, so that the transformer and the temperature acquisition module can be tightly and firmly connected, and the transformer coil temperature can be accurately collected.

[0022] The temperature acquisition module includes a sampling resistor and a temperature switch. The sampling resistor is used to collect temperature information, and the temperature switch is used to control whether to connect to the over-temperature protection circuit. The sampling resistor and the temperature switch are connected in series, one end is connected to the auxiliary power module, and the other end is connected to the over-temperature protection circuit. When the temperature sampled by the sampling resistor reaches the set value, the temperature switch is closed, the sampling resistor is connected to the over-temperature protection circuit, and the over-temperature protection circuit starts to work to protect the switching power supply transformer.

[0023] The circuit diagram of the over-temperature protection module is as follows: Figure 3As shown, it includes an over-temperature display circuit, a protection circuit and a fault output circuit. The over-temperature display circuit is used to display over-temperature information, the protection circuit is used to output a protection signal, and the fault output circuit is used to output fault information. The input ends of the over-temperature display circuit, the protection circuit and the fault output circuit are connected to the output end of the temperature acquisition module, the output end of the over-temperature display circuit is connected to the input end of the display, the protection circuit is connected to the control end of the main control chip of the switching power supply, and the output end of the fault output circuit is connected to the fault output end of the main control chip.

[0024] The over-temperature display circuit includes a capacitor C48 and a diode V42. One end of the capacitor C48 is connected to the output end of the temperature acquisition module, the other end of the capacitor C48 is grounded, the cathode of the diode V42 is connected to the output end of the temperature acquisition module, and the anode of the diode V42 is connected to the display.

[0025] The protection circuit includes a diode V06, a current limiting resistor R42, and a transistor V13 which are connected in series at the output end of the temperature acquisition module. The collector of the transistor is connected to the control end of the switching power supply main control chip through a diode V60. The anode of the diode V06 is connected to the output end of the temperature acquisition module. The cathode of the diode V06 is connected to the base of the transistor V13 through the current limiting resistor R42. The emitter of the transistor V13 is connected to the ground through a resistor R26.

[0026] The fault output circuit includes a diode V70 and a current limiting resistor R71 connected to the negative output end of the diode V06. The other end of the current limiting resistor R71 is connected to the fault output end of the main control chip. The positive electrode of the diode V70 is connected to the negative electrode of the diode V06, and the negative electrode of the diode V70 is connected to the current limiting resistor R71.

[0027] When the utility model is working, the over-temperature protection circuit takes the VCC voltage from the auxiliary power supply module, and is connected to the temperature acquisition module integrated in the transformer by means of flying wires. When the transformer reaches the set temperature of the temperature acquisition module, the temperature switch in the temperature acquisition module is closed. At this time, after the VCC voltage signal passes through the temperature switch, one path is transmitted to the front panel display through C48 and diode V42 for over-temperature alarm; the second path is transmitted to the main control chip through diode V06, current limiting resistor R42, transistor V13, etc. to control the module to shut down; the third path passes through diode V70 and current limiting resistor R71 to control the relay to close, thereby realizing the external fault signal output.

Claims

1. A switching power supply transformer over-temperature protection circuit, characterized in that: The invention comprises a temperature acquisition module (2) arranged on the transformer for acquiring the temperature of the transformer, an over-temperature protection module for issuing an over-temperature protection signal, and an auxiliary power supply module for providing power, wherein the output end of the auxiliary power supply module is respectively connected to the power input ends of the temperature acquisition module and the over-temperature protection module, the output end of the temperature acquisition module is connected to the input end of the over-temperature protection module, and the output end of the over-temperature protection module is connected to the input end of the switch power supply main control chip; the output end of the over-temperature protection circuit is connected to a display for displaying over-temperature alarm information.

2. The over-temperature protection circuit of a switching power supply transformer according to claim 1, characterized in that: The auxiliary power supply module and the temperature acquisition module are connected via a twisted pair, the auxiliary power supply module and the over-temperature protection module are connected via circuit board routing, and the temperature acquisition module and the over-temperature protection module are connected via flying wires.

3. The over-temperature protection circuit of a switching power supply transformer according to claim 1, characterized in that: The temperature acquisition module (2) is arranged on the outer layer of the transformer secondary coil (1), and comprises a sampling resistor for collecting temperature information and a temperature switch for controlling whether to connect the over-temperature protection circuit, which are connected in series. The sampling resistor and the temperature switch are connected in series, one end of which is connected to the auxiliary power supply module, and the other end of which is connected to the over-temperature protection circuit.

4. The over-temperature protection circuit of a switching power supply transformer according to claim 1, characterized in that: The over-temperature protection module includes an over-temperature display circuit for displaying over-temperature information, a protection circuit for outputting a protection signal, and a fault output circuit for outputting fault information. The input ends of the over-temperature display circuit, the protection circuit, and the fault output circuit are connected to the output end of the temperature acquisition module, the output end of the over-temperature display module is connected to the input end of the display, the protection circuit is connected to the control end of the main control chip of the switching power supply, and the output end of the fault output circuit is connected to the fault output end of the main control chip.

5. The over-temperature protection circuit of a switching power supply transformer according to claim 4, characterized in that: The over-temperature display circuit includes a capacitor C48 and a diode V42, one end of the capacitor C48 is connected to the output end of the temperature acquisition module, the other end of the capacitor C48 is grounded, the cathode of the diode V42 is connected to the output end of the temperature acquisition module, and the anode of the diode V42 is connected to the display.

6. The over-temperature protection circuit of a switching power supply transformer according to claim 4, characterized in that: The protection circuit includes a diode V06, a current limiting resistor R42, and a transistor V13 which are connected in series at the output end of the temperature acquisition module in sequence. The collector of the transistor is connected to the control end of the switching power supply main control chip through a diode V60. The anode of the diode V06 is connected to the output end of the temperature acquisition module. The cathode of the diode V06 is connected to the base of the transistor V13 through the current limiting resistor R42. The emitter of the transistor V13 is connected to the ground through a resistor R26.

7. The over-temperature protection circuit of a switching power supply transformer according to claim 4, characterized in that: The fault output circuit includes a diode V70 and a current limiting resistor R71 connected to the cathode output end of the diode V06. The other end of the current limiting resistor R71 is connected to the fault output end of the main control chip. The anode of the diode V70 is connected to the cathode of the diode V06, and the cathode of the diode V70 is connected to the current limiting resistor R71.

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