Thermal protection circuit

Patent metadata

Field	Value
Publication number	US-9819172-B2
Application number	US-201514753245-A
Country	US
Kind code	B2
Filing date	Jun 29, 2015
Priority date	Apr 8, 2013
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

A thermal protection circuit which relates to the field of electronic technologies can detect temperature of multiple locations simultaneously and adjust a preset threshold flexibly, thereby improving system reliability. The thermal protection circuit includes: at least one temperature sensor, a detection circuit, an execution circuit, a self-locking and triggering circuit, a protective temperature regulation circuit, and a power supply circuit. The at least one temperature sensor converts a temperature signal into an electrical signal and sends the electrical signal to the detection circuit; the detection circuit detects whether temperature reaches the preset threshold, and sends a turn-off signal to the execution circuit if the temperature reaches the preset threshold; the execution circuit cuts off power supply to the system; and the self-locking and triggering circuit maintains, a power-off state of the system until a power switch is triggered.

First claim

What is claimed is:

1. A thermal protection circuit for a system, comprising:
a detection circuit;
an execution circuit;
a self-locking and triggering circuit; and
at least one temperature sensor, wherein the temperature sensor is configured to:
convert a temperature signal into an electrical signal; and
send the electrical signal to the detection circuit,

wherein the detection circuit is coupled to the temperature sensor and configured to:
detect, according to the electrical signal, whether a temperature of the system reaches a preset threshold temperature; and
send a turn-off signal to an execution circuit when the temperature reaches the preset threshold temperature,

wherein the execution circuit is coupled to the detection circuit and configured to cut off power to the system after receiving the turn-off signal, and
wherein the self-locking and triggering circuit is coupled to a power supply circuit and comprises:
a first diode;
a second diode coupled to the first diode;
a field-effect transistor coupled to the temperature sensor; and
a power switch coupled to each of the first and the second diodes, wherein the power switch is connected to a first connection point between a cathode of the first diode and a cathode of the second diode, wherein an anode of the first diode is connected to a second connection point between the temperature sensor and the field-effect transistor, and wherein an anode of the second diode is connected to the power supply circuit.

2. The thermal protection circuit according to claim 1 , wherein the temperature sensor is disposed outside a protected component, and wherein a distance between the temperature sensor and the protected component is within a specified range so that the protected component is within a monitoring range of the temperature sensor.

3. The thermal protection circuit according to claim 1 , wherein the self-locking and triggering circuit further comprises a first resistor with a first and a second resistor terminal, wherein the first resistor terminal is coupled to ground and the second resistor terminal is connected to a third connection point between the field effect transistor and the power supply circuit, wherein a first end of the field effect transistor is connected to the temperature sensor, wherein a second end of the field effect transistor is connected to the power supply circuit, and wherein a third and a fourth end of the field effect transistor are connected to the ground.

4. The thermal protection circuit according to claim 1 , wherein the detection circuit comprises a comparing circuit, wherein the comparing circuit comprises a comparator, wherein a first input end of the comparing circuit is connected to a protective temperature regulation circuit, and wherein a second input end of the comparing circuit is connected to the temperature sensor, and wherein an output end of the comparing circuit is connected to the execution circuit.

5. The thermal protection circuit according to claim 1 , wherein the detection circuit comprises a comparing circuit, wherein the comparing circuit comprises a microcontroller, wherein a first input end of the comparing circuit is connected to a protective temperature regulation circuit, and wherein a second input end of the comparing circuit is connected to the temperature sensor, and wherein an output end of the comparing circuit is connected to the execution circuit.

6. The thermal protection circuit according to claim 2 , wherein the execution circuit comprises a field effect transistor, wherein a first end of the execution circuit is connected to the detection circuit, wherein a second end of the execution circuit is connected to the power supply circuit in which the protected component in the system is located, and wherein a third end of the execution circuit is connected to a power source.

7. The thermal protection circuit according to claim 2 , wherein the execution circuit comprises a load switch, wherein a first end of the execution circuit is connected to the detection circuit, wherein a second end of the execution circuit is connected to the power supply circuit in which the protected component in the system is located, and wherein a third end of the execution circuit is connected to a power source.

8. The thermal protection circuit according to claim 1 , further comprising a protective temperature regulation circuit, wherein the protective temperature regulation circuit is configured to adjust the preset threshold temperature.

9. The thermal protection circuit according to claim 1 , wherein the self-locking and triggering circuit is configured to maintain, after the power to the system is cut off, a power-off state of the system until the power switch is triggered.

10. The thermal protection circuit according to claim 1 , wherein the detection circuit comprises a comparing circuit, wherein the comparing circuit comprises an operational amplifier, and wherein a first input end of the comparing circuit is connected to a protective temperature regulation circuit, a second input end of the comparing circuit is connected to the temperature sensor, and an output end of the comparing circuit is connected to the execution circuit.

11. A thermal protection circuit for a system, comprising:
at least one temperature sensor, wherein the temperature sensor is configured to convert a temperature signal into an electrical signal;
a detection circuit coupled to the temperature sensor and configured to generate a turn-off signal when a temperature of the system reaches a preset threshold temperature;
an execution circuit coupled to the detection circuit and configured to cut off power to the system according to the turn-off signal, and
a self-locking and triggering circuit coupled to a power supply circuit and configured to maintain a power-off state of the system until a power switch is triggered, wherein the self-locking and triggering circuit comprises:
a first diode;
a second diode coupled to the first diode;
a field-effect transistor coupled to the temperature sensor; and
wherein the power switch is coupled to each of the first and the second diodes, wherein the power switch is connected to a first connection point between a cathode of the first diode and a cathode of the second diode, wherein an anode of the first diode is connected to a second connection point between the temperature sensor and the field-effect transistor, and wherein an anode of the second diode is connected to the power supply.

12. The thermal protection circuit according to claim 11 , wherein the temperature sensor is disposed outside a protected component, and wherein a distance between the temperature sensor and the protected component is within a specified range so that the protected component is within a monitoring range of the temperature sensor.

13. The thermal protection circuit according to claim 11 , wherein the self-locking and triggering circuit further comprises a first resistor with a first and a second resistor terminal, wherein the first resistor terminal is coupled to ground and the second resistor terminal is connected to a third connection point between the field effect transistor and a power supply circuit, wherein a first end of the field effect transistor is connected to the temperature sensor, wherein a second end of the field effect transistor is connected to the power supply circuit, and wherein a third and a fourth end of the field effect transistor are connected to the ground.

14. The thermal protection circuit according to claim 11 , wherein the detection circuit comprises a comparing circuit, wherein the comparing circuit comp

Assignees

• Huawei Device Co Ltd
• Huawei Device (Dongguan) Co Ltd

Inventors

• Li Changqi
• Luo Bingwu

Classifications

• H02H5/042 Primary

  using temperature dependent resistors · CPC title