CN210579190U

CN210579190U - Audio circuit

Info

Publication number: CN210579190U
Application number: CN201921843172.XU
Authority: CN
Inventors: 陆明球
Original assignee: Dongguan Tingfeng Electronic Co ltd
Current assignee: Dongguan Tingfeng Electronic Co ltd
Priority date: 2019-10-30
Filing date: 2019-10-30
Publication date: 2020-05-19
Anticipated expiration: 2029-10-30

Abstract

The utility model relates to an audio circuit. The system comprises a processor, a DSP circuit, a BTL power amplifier circuit and a power supply circuit, wherein the power supply circuit respectively provides power for the processor, the DSP circuit and the BTL power amplifier circuit; the processor is respectively and electrically connected with the DSP circuit and the BTL power amplification circuit; the protection circuit is electrically connected with the BTL power amplification circuit and the processor respectively; the protection circuit comprises an over-temperature protection circuit, a horn output end direct current protection circuit and a power supply overvoltage protection circuit. The utility model can protect the BTL power amplifier circuit from over-temperature and over-voltage by arranging the protection circuit; meanwhile, the power amplifier circuit can be prevented from abnormally damaging equipment.

Description

Audio circuit

Technical Field

The utility model relates to a stereo set technical field especially relates to an audio circuit.

Background

Most of power amplifier circuits in the market at present are designed by taking a model IRS2092 chip as a driving chip, and along with the continuous development of electronic technology, the integrated functions of sound are more and more; the peripheral circuits of the power amplifier circuit are gradually enriched, so that the power on the power amplifier circuit board is larger, and the heat productivity is larger; when the external temperature is higher or the environment is sealed, the internal temperature is easy to be overhigh; cause inside electronic component's damage, especially BTL power amplifier circuit, and at present because the volume of stereo set is less, be unsuitable for installing radiator fan etc. in the stereo set, for the power amplifier circuit board that prevents the stereo set damages, need design a protection circuit to BTL power amplifier circuit, when inside high temperature, can control power amplifier circuit through CPU and stop work.

Disclosure of Invention

An object of the utility model is to provide an audio circuit to prior art not enough, this audio circuit can avoid the excess temperature to damage BTL power amplifier circuit.

An audio circuit comprises a processor, a DSP circuit, a BTL power amplifier circuit and a power circuit, wherein the power circuit respectively provides power for the processor, the DSP circuit and the BTL power amplifier circuit; the processor is respectively and electrically connected with the DSP circuit and the BTL power amplification circuit; the protection circuit is electrically connected with the BTL power amplification circuit and the processor respectively; the protection circuit comprises an over-temperature protection circuit, the over-temperature protection circuit comprises a switching tube, the output end of the switching tube is electrically connected with the processor through a resistor R89, the input end of the switching tube is connected with a power supply, the control end of the switching tube is connected with an adjusting circuit, the adjusting circuit comprises a triode Q19 and an NTC resistor, the power supply is grounded through a resistor R60 and a resistor R58 which are connected in series, the power supply is grounded through a resistor R90 and an NTC resistor which are connected in series, the base electrode of the triode Q19 is connected with the output end of a resistor R60, and the collector electrode of the triode Q19 is connected with the input end of the; the collector of the triode Q19 is connected with the control end of the switch tube through a resistor R86; when the temperature rises to reach a preset value, the NTC resistor is changed to be conducted by the triode Q19, the potential of the control end of the switch tube rises, the switch tube is conducted, the power supply is electrically connected with the processor through the switch tube and the resistor R89, the potential of the induction end of the processor is pulled down, and the processor controls the power amplifier chip to stop working.

Further, the switching tube is a transistor Q17.

Furthermore, the protection circuit also comprises a horn output end direct current protection circuit, wherein the horn output end direct current protection circuit comprises a resistor R38 and a resistor R41 which are respectively used for being connected with two signal output ends of the BTL power amplification circuit, and further comprises a PNP type triode Q6, a PNP type triode Q15 and an NPN type triode Q12; the output end of the resistor R38 and the output end of the resistor R41 are both connected with an emitter of the triode Q6, the output end of the resistor R41 is grounded through a capacitor C39, and the capacitor C39 is connected with a resistor R40 in parallel; the positive electrode of the capacitor C39 is connected with the base electrode of the triode Q15, the emitting electrode of the triode Q15 is connected with the base electrode of the triode Q6, the collecting electrode of the triode Q15 and the collecting electrode of the triode Q6 are connected with the base electrode of the triode Q12 through a resistor R49, the emitting electrode of the triode Q12 is connected with a power supply of-5V through an electrothermal C84, and the collecting electrode of the triode Q12 is connected with the processor through a resistor R72.

Furthermore, the protection circuit also comprises a power supply overvoltage protection circuit, the power supply overvoltage protection circuit comprises a switch diode ZD1 and a PNP type triode Q18, the positive electrode of the power supply of the BTL power amplification circuit is connected with the negative electrode of an inverted switch diode ZD1, and the positive electrode of the switch diode ZD1 is grounded through a resistor R29 and a resistor R30 which are connected in series; the output end of the resistor R29 is connected with the base electrode of the triode Q18 through the resistor R123, the emitter electrode of the triode Q18 is grounded, and the emitter electrode of the triode Q18 is connected with the processor through the resistor R47.

The utility model has the advantages that: the utility model can protect the BTL power amplifier circuit from over-temperature and over-voltage by arranging the protection circuit; meanwhile, the power amplifier circuit can be prevented from abnormally damaging equipment.

Drawings

Fig. 1 is a schematic circuit diagram of an audio circuit according to the present embodiment.

Fig. 2 is a schematic diagram of a framework of an audio circuit.

Fig. 3 is a schematic circuit diagram of the over-temperature protection circuit.

Fig. 4 is a schematic circuit diagram of a dc protection circuit at the output end of the horn.

Fig. 5 is a schematic circuit diagram of a power supply overvoltage protection circuit.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings. As shown in fig. 1-5.

Example 1: an audio circuit comprises a processor, a DSP circuit, a BTL power amplifier circuit and a power circuit, wherein the power circuit respectively provides power for the processor, the DSP circuit and the BTL power amplifier circuit; the processor is respectively and electrically connected with the DSP circuit and the BTL power amplification circuit; the protection circuit is electrically connected with the BTL power amplification circuit and the processor respectively; the protection circuit comprises an over-temperature protection circuit, the over-temperature protection circuit comprises a switching tube, the output end of the switching tube is electrically connected with the processor through a resistor R89, the input end of the switching tube is connected with a power supply, the control end of the switching tube is connected with an adjusting circuit, the adjusting circuit comprises a triode Q19 and an NTC resistor, the power supply is grounded through a resistor R60 and a resistor R58 which are connected in series, the power supply is grounded through a resistor R90 and an NTC resistor which are connected in series, the base electrode of the triode Q19 is connected with the output end of a resistor R60, and the collector electrode of the triode Q19 is connected with the input end of the; the collector of the triode Q19 is connected with the control end of the switch tube through a resistor R86; when the temperature rises to reach a preset value, the NTC resistor is changed to be conducted by the triode Q19, the potential of the control end of the switch tube rises, the switch tube is conducted, the power supply is electrically connected with the processor through the switch tube and the resistor R89, the potential of the induction end of the processor is pulled down, and the processor controls the power amplifier chip to stop working.

The DSP circuit, the BTL power amplifier circuit and the processor in the audio circuit can all be the prior art, the technical scheme is additionally provided with a protection circuit on the prior art, the protection circuit comprises an over-temperature protection circuit, and the type of a triode Q19 in the over-temperature protection circuit corresponds to the type of an NTC resistor; the NTC resistor is arranged near the power amplifier chip and used for sensing the temperature of the power amplifier chip; when the method is specifically set: the resistor R60 and the resistor 58 are connected in series between a power supply and the ground and form a reference circuit, the potential of the connection point of the resistor R60 and the resistor R58 is a reference potential, namely the potential of the base of the transistor Q19 is the reference potential, the potential of the connection point of the resistor R90 and the NTC resistor changes along with the temperature, the potential of the emitter of the transistor Q19 is a changing potential, and when the temperature rises, the potential of the emitter of the transistor Q19 changes until the transistor Q19 is conducted; and when the triode Q19 is switched on, the potential of the control end of the switch tube rises, the switch tube is switched on, the level of the control end of the processor is pulled down, and the processor sends a signal to the power amplifier chip to control the power amplifier chip to stop working. The MCU in fig. 1 is a processor.

Further, the switching tube is a transistor Q17.

The switch tube can be other electronic elements, such as a MOS tube and the like. The technical scheme adopts a triode as a switching tube.

When the BTL power amplifier circuit is abnormal, two signal ends of the loudspeaker have direct current offset higher than the set value, the DCP circuit is needed to protect the safety of the loudspeaker and the power device, and equipment is guaranteed not to be damaged. The reference is made to-5 VA, the resistor R38 and the resistor R41 are direct current detection resistors, under the normal working condition, the amplitudes of signals at the SUB _ OUT +/SUB _ OUT-ends are equal, the polarities are opposite, the positive electrodes of the capacitor C39 are mutually offset to be 0 level, when a direct current component appears at any end of the SUB _ OUT + or the SUB _ OUT-, and a direct current voltage difference is greater than 600mV, and the direct current component is loaded to the base electrode of the triode Q6 or the base electrode of the triode Q15, the triode Q6 or the triode Q15 is conducted, meanwhile, the triode Q12 is conducted, the 3.3V level on the resistor R72 is reduced to about 0.2V, and after the MCU detects the low level, the DCP is triggered to cut off the power amplifier output, and the power supply of the power amplifier is turned off at the.

The power supply anode is the anode of a power discharge source, when a power amplifier power supply abnormally rises, and the power supply anode rises to a set upper limit value of 82V, the switch diode ZD1 breaks down, the base of the triode Q18 reaches a 0.6V level and is conducted, at the moment, the 3.3V level on the resistor R47 is pulled down to a low level about 0.2V, and after the MCU detects the low level, the OVP protection action is triggered to cut off the PWM output of the power amplifier, and meanwhile, the power amplifier power supply is closed, so that a loudspeaker and equipment are protected.

The above description is only for the preferred embodiment of the present invention, and for those skilled in the art, there are variations on the detailed description and the application scope according to the idea of the present invention, and the content of the description should not be construed as a limitation to the present invention.

Claims

1. An audio circuit comprises a processor, a DSP circuit, a BTL power amplifier circuit and a power circuit, wherein the power circuit respectively provides power for the processor, the DSP circuit and the BTL power amplifier circuit; the processor is respectively and electrically connected with the DSP circuit and the BTL power amplification circuit; the method is characterized in that: the protection circuit is electrically connected with the BTL power amplification circuit and the processor respectively; the protection circuit comprises an over-temperature protection circuit, the over-temperature protection circuit comprises a switching tube, the output end of the switching tube is electrically connected with the processor through a resistor R89, the input end of the switching tube is connected with a power supply, the control end of the switching tube is connected with an adjusting circuit, the adjusting circuit comprises a triode Q19 and an NTC resistor, the power supply is grounded through a resistor R60 and a resistor R58 which are connected in series, the power supply is grounded through a resistor R90 and an NTC resistor which are connected in series, the base electrode of the triode Q19 is connected with the output end of a resistor R60, and the collector electrode of the triode Q19 is connected with the input end of the; the collector of the triode Q19 is connected with the control end of the switch tube through a resistor R86; when the temperature rises to reach a preset value, the NTC resistor is changed to be conducted by the triode Q19, the potential of the control end of the switch tube rises, the switch tube is conducted, the power supply is electrically connected with the processor through the switch tube and the resistor R89, the potential of the induction end of the processor is pulled down, and the processor controls the power amplifier chip to stop working.

2. The audio circuit of claim 1, wherein: the switching tube is a triode Q17.

3. The audio circuit of claim 1, wherein: the protection circuit further comprises a horn output end direct current protection circuit, the horn output end direct current protection circuit comprises a resistor R38 and a resistor R41 which are respectively used for being connected with two signal output ends of the BTL power amplification circuit, and further comprises a PNP type triode Q6, a PNP type triode Q15 and an NPN type triode Q12; the output end of the resistor R38 and the output end of the resistor R41 are both connected with an emitter of the triode Q6, the output end of the resistor R41 is grounded through a capacitor C39, and the capacitor C39 is connected with a resistor R40 in parallel; the positive electrode of the capacitor C39 is connected with the base electrode of the triode Q15, the emitting electrode of the triode Q15 is connected with the base electrode of the triode Q6, the collecting electrode of the triode Q15 and the collecting electrode of the triode Q6 are connected with the base electrode of the triode Q12 through a resistor R49, the emitting electrode of the triode Q12 is connected with a power supply of-5V through an electrothermal C84, and the collecting electrode of the triode Q12 is connected with the processor through a resistor R72.

4. The audio circuit of claim 1, wherein: the protection circuit further comprises a power supply overvoltage protection circuit, the power supply overvoltage protection circuit comprises a switch diode ZD1 and a PNP type triode Q18, the positive electrode of the power supply of the BTL power amplification circuit is connected with the negative electrode of an inverted switch diode ZD1, and the positive electrode of the switch diode ZD1 is grounded through a resistor R29 and a resistor R30 which are connected in series; the output end of the resistor R29 is connected with the base electrode of the triode Q18 through the resistor R123, the emitter electrode of the triode Q18 is grounded, and the emitter electrode of the triode Q18 is connected with the processor through the resistor R47.