CN104682889A - Over-temperature protection circuit for loudspeaker box power amplifier - Google Patents
Over-temperature protection circuit for loudspeaker box power amplifier Download PDFInfo
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- CN104682889A CN104682889A CN201310630093.1A CN201310630093A CN104682889A CN 104682889 A CN104682889 A CN 104682889A CN 201310630093 A CN201310630093 A CN 201310630093A CN 104682889 A CN104682889 A CN 104682889A
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- isolated gate
- operational amplifier
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Abstract
The invention discloses an over-temperature protection circuit for a loudspeaker box power amplifier. The over-temperature protection circuit for the loudspeaker box power amplifier comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first insulated gate field-effect transistor, a second insulated gate field-effect transistor, a third insulated gate field-effect transistor, a fourth insulated gate field-effect transistor, a triode, a capacitor, an operational amplifier, a phase inverter and a direct-current power source, wherein a comparison circuit is formed by the fifth resistor, the sixth resistor, the first insulated gate field-effect transistor, the second insulated gate field-effect transistor, the triode and the operational amplifier, and a positive feedback circuit is formed by the third insulated gate field-effect transistor, the fourth insulated gate field-effect transistor, the capacitor and the phase inverter. According to the over-temperature protection circuit for the loudspeaker box power amplifier, temperature changes are converted into voltage signals, the voltage signals are input to the operational amplifier to be compared, and an over-temperature protection signal is generated. Due to the fact that the positive feedback circuit is added to the over-temperature protection circuit, sensitivity is high, and reliability is high.
Description
Technical field
The present invention relates to a kind of thermal-shutdown circuit for audio amplifier power amplifier, particularly relate to a kind of highly sensitive thermal-shutdown circuit for audio amplifier power amplifier.
Background technology
In the process of audio amplifier power amplifier work, inevitably power loss, these loss overwhelming majority will convert heat energy to and shed.In the situations such as, short circuit too high in ambient temperature, heat can not shed in time, thus causes the temperature of woofer amplifier sharply to rise, and temperature rising can cause the decrease in efficiency of amplifier, even can burn amplifier.The thermal-shutdown circuit sensitivity of current woofer amplifier is lower, cannot turn off amplifier rapidly.
Summary of the invention
Object of the present invention is just to provide a kind of highly sensitive thermal-shutdown circuit for audio amplifier power amplifier to solve the problem.
The present invention is achieved through the following technical solutions above-mentioned purpose:
Thermal-shutdown circuit for audio amplifier power amplifier of the present invention, comprises the first resistance, second resistance, 3rd resistance, 4th resistance, 5th resistance, 6th resistance, first isolated gate FET, second isolated gate FET, 3rd isolated gate FET, 4th isolated gate FET, triode, electric capacity, operational amplifier, inverter and DC power supply, the first end of described first resistance is as the signal input part of described thermal-shutdown circuit, second end of described first resistance is connected with the grid of described first isolated gate FET, the source electrode of described first isolated gate FET simultaneously with the first end of described second resistance, the grid of described second isolated gate FET connects, the drain electrode of described first isolated gate FET simultaneously with the emitter of described triode, the inverting input of described operational amplifier connects, the source electrode of described second isolated gate FET simultaneously with the first end of described 3rd resistance, the grid of described 3rd isolated gate FET connects, the source electrode of described 3rd isolated gate FET is connected with the first end of described 4th resistance, the drain electrode of described 3rd isolated gate FET is connected with the source electrode of described 4th isolated gate FET, the drain electrode of described second isolated gate FET simultaneously with the first end of described 5th resistance, the first end of described electric capacity, the drain electrode of described 4th isolated gate FET, the in-phase input end of described operational amplifier connects, the base stage of described triode simultaneously with the second end of described 5th resistance, the first end of described 6th resistance connects, the positive pole of described DC power supply simultaneously with the second end of described second resistance, second end of described 3rd resistance, second end of described 4th resistance, the power positive end of described operational amplifier connects, the negative pole of described DC power supply simultaneously with the collector electrode of described triode, second end of described 6th resistance, second end of described electric capacity, the power-of described operational amplifier extremely connects, the output of described operational amplifier is connected with the input of described inverter, and the output of described inverter is connected with the grid of described 4th isolated gate FET and as the signal output part of described thermal-shutdown circuit.
Beneficial effect of the present invention is:
Thermal-shutdown circuit for audio amplifier power amplifier of the present invention, converts variations in temperature to voltage signal input operational amplifier and compares, and produces temperature protection signal.This thermal-shutdown circuit is added with regenerative circuit, highly sensitive, and reliability is high.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of the thermal-shutdown circuit for audio amplifier power amplifier of the present invention.
Embodiment
Below in conjunction with accompanying drawing, the invention will be further described:
As shown in Figure 1, the thermal-shutdown circuit for audio amplifier power amplifier of the present invention, comprises the first resistance R1, second resistance R2, 3rd resistance R3, 4th resistance R4, 5th resistance R5, 6th resistance R6, first isolated gate FET M1, second isolated gate FET M2, 3rd isolated gate FET M3, 4th isolated gate FET M4, triode Q, electric capacity C, operational amplifier A, inverter NT and DC power supply (in figure Vcc), the first end of the first resistance R1 is as the signal input part IN of thermal-shutdown circuit, second end of the first resistance R1 is connected with the grid of the first isolated gate FET M1, the source electrode of the first isolated gate FET M1 simultaneously with the first end of the second resistance R2, the grid of the second isolated gate FET M2 connects, the drain electrode of the first isolated gate FET M1 simultaneously with the emitter of triode Q, the inverting input of operational amplifier A connects, the source electrode of the second isolated gate FET M2 simultaneously with the first end of the 3rd resistance R3, the grid of the 3rd isolated gate FET M3 connects, the source electrode of the 3rd isolated gate FET M3 is connected with the first end of the 4th resistance R4, the drain electrode of the 3rd isolated gate FET M3 is connected with the source electrode of the 4th isolated gate FET M4, the drain electrode of the second isolated gate FET M2 simultaneously with the first end of the 5th resistance R5, the first end of electric capacity C, the drain electrode of the 4th isolated gate FET M4, the in-phase input end of operational amplifier A connects, the base stage of triode Q simultaneously with second end of the 5th resistance R5, the first end of the 6th resistance R6 connects, the positive pole of DC power supply simultaneously with second end of the second resistance R2, second end of the 3rd resistance R3, second end of the 4th resistance R4, the power positive end of operational amplifier A connects, the negative pole of DC power supply simultaneously with the collector electrode of triode Q, second end of the 6th resistance R6, second end of electric capacity C, the power-of operational amplifier A extremely connects, and the output of operational amplifier A is connected with the input of inverter NT, and the output of inverter NT is connected with the grid of the 4th isolated gate FET M4 and as the signal output part OUT of thermal-shutdown circuit.
Thermal-shutdown circuit for audio amplifier power amplifier of the present invention; 5th resistance R5, the 6th resistance R6, the first isolated gate FET M1, the second isolated gate FET M2, triode Q and operational amplifier A form comparison circuit, and the 3rd isolated gate FET M3, the 4th isolated gate FET M4, electric capacity C and inverter NT form regenerative circuit.The variations in temperature signal from thermistor of the signal input part IN input of this thermal-shutdown circuit; variations in temperature signal is converted to voltage signal input operational amplifier A to compare; operational amplifier A exports high level when the set temperature is reached; output low level after inverter NT; produce temperature protection signal and output to control end shutoff amplifier, reach the object of guard amplifier.Meanwhile, the grid that the low level signal that inverter NT exports is added to the 4th isolated gate FET M4 makes its conducting, the voltage difference of the input of operational amplifier A is increased, and improves sensitivity.
Claims (1)
1. for a thermal-shutdown circuit for audio amplifier power amplifier, it is characterized in that: comprise the first resistance, second resistance, 3rd resistance, 4th resistance, 5th resistance, 6th resistance, first isolated gate FET, second isolated gate FET, 3rd isolated gate FET, 4th isolated gate FET, triode, electric capacity, operational amplifier, inverter and DC power supply, the first end of described first resistance is as the signal input part of described thermal-shutdown circuit, second end of described first resistance is connected with the grid of described first isolated gate FET, the source electrode of described first isolated gate FET simultaneously with the first end of described second resistance, the grid of described second isolated gate FET connects, the drain electrode of described first isolated gate FET simultaneously with the emitter of described triode, the inverting input of described operational amplifier connects, the source electrode of described second isolated gate FET simultaneously with the first end of described 3rd resistance, the grid of described 3rd isolated gate FET connects, the source electrode of described 3rd isolated gate FET is connected with the first end of described 4th resistance, the drain electrode of described 3rd isolated gate FET is connected with the source electrode of described 4th isolated gate FET, the drain electrode of described second isolated gate FET simultaneously with the first end of described 5th resistance, the first end of described electric capacity, the drain electrode of described 4th isolated gate FET, the in-phase input end of described operational amplifier connects, the base stage of described triode simultaneously with the second end of described 5th resistance, the first end of described 6th resistance connects, the positive pole of described DC power supply simultaneously with the second end of described second resistance, second end of described 3rd resistance, second end of described 4th resistance, the power positive end of described operational amplifier connects, the negative pole of described DC power supply simultaneously with the collector electrode of described triode, second end of described 6th resistance, second end of described electric capacity, the power-of described operational amplifier extremely connects, the output of described operational amplifier is connected with the input of described inverter, and the output of described inverter is connected with the grid of described 4th isolated gate FET and as the signal output part of described thermal-shutdown circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310630093.1A CN104682889A (en) | 2013-11-29 | 2013-11-29 | Over-temperature protection circuit for loudspeaker box power amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310630093.1A CN104682889A (en) | 2013-11-29 | 2013-11-29 | Over-temperature protection circuit for loudspeaker box power amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104682889A true CN104682889A (en) | 2015-06-03 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310630093.1A Pending CN104682889A (en) | 2013-11-29 | 2013-11-29 | Over-temperature protection circuit for loudspeaker box power amplifier |
Country Status (1)
| Country | Link |
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| CN (1) | CN104682889A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110320952A (en) * | 2019-07-22 | 2019-10-11 | 苏州欧普照明有限公司 | A kind of thermal-shutdown circuit and system |
| CN114025413A (en) * | 2017-12-19 | 2022-02-08 | 海能达通信股份有限公司 | Temperature protection circuit and electronic equipment |
-
2013
- 2013-11-29 CN CN201310630093.1A patent/CN104682889A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114025413A (en) * | 2017-12-19 | 2022-02-08 | 海能达通信股份有限公司 | Temperature protection circuit and electronic equipment |
| CN114025413B (en) * | 2017-12-19 | 2023-12-19 | 海能达通信股份有限公司 | Temperature protection circuit and electronic equipment |
| CN110320952A (en) * | 2019-07-22 | 2019-10-11 | 苏州欧普照明有限公司 | A kind of thermal-shutdown circuit and system |
| CN110320952B (en) * | 2019-07-22 | 2024-05-31 | 苏州欧普照明有限公司 | Over-temperature protection circuit and system |
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| C06 | Publication | ||
| PB01 | Publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20150603 |