CN209897011U - Power amplifier output direct current monitoring circuit when power amplifier carries out short-circuit protection test - Google Patents
Power amplifier output direct current monitoring circuit when power amplifier carries out short-circuit protection test Download PDFInfo
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- CN209897011U CN209897011U CN201920879720.8U CN201920879720U CN209897011U CN 209897011 U CN209897011 U CN 209897011U CN 201920879720 U CN201920879720 U CN 201920879720U CN 209897011 U CN209897011 U CN 209897011U
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Abstract
The utility model discloses a power amplifier output direct current monitoring circuit when power amplifier carries out short-circuit protection test, singlechip including first operational amplifier, second operational amplifier and power amplifier, the negative pole input pin of first operational amplifier is connected with series connection's input resistance, and the normal phase signal of power amplifier output is sent to first operational amplifier through series connection's input resistance, and the inverted phase signal of power amplifier output passes through input resistance and ground capacitance, ground resistance to first operational amplifier, and first operational amplifier carries out the difference operation; the first operational amplifier is connected with the second operational amplifier through an RC filter; and an output end pin of the second operational amplifier is connected to the singlechip through an isolation resistor and an input resistor of the singlechip. The power amplifier is when carrying out the short-circuit protection test, the utility model discloses can the accurate output direct current that detects the power amplifier, ensure the safety of power amplifier, circuit structure is simple.
Description
Technical Field
The utility model relates to a power amplifier technical field, concretely relates to power amplifier output direct current monitoring circuit's when power amplifier carries out the short-circuit protection test technique.
Background
At present, a digital power amplifier circuit applied to a professional class D power amplifier product is mainly applied on the basis of an IR (infrared radiation) driver chip, for example, the IR IRS20957S driver chip is a digital audio driver chip, an overcurrent protection circuit is integrated in the driver chip, different power amplifier output powers are designed, external parameters need to be adjusted to match different MOS (metal oxide semiconductor) tubes, and the sensitivity of a protection circuit is very difficult to adjust because the overcurrent protection and the RDS (remote data service) temperature rise of an external MOS (metal oxide semiconductor) have close relation. Therefore, when the output end of the power amplifier is subjected to long-term short circuit test, the power amplifier can be damaged. Therefore, a protection circuit is generally designed for the power amplifier, a single chip microcomputer is used as a core, and the power amplifier is protected in a full range to work in a safe state by monitoring the output voltage and the output current of the power amplifier, outputting the frequency, supplying the power voltage of the power amplifier, and dynamically tracking the temperature of a power MOS tube. In the protection circuit, an operational amplifier circuit is often used, and it is necessary to accurately detect the load current.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects of the prior art, the utility model aims to provide a power amplifier output direct current monitoring circuit when power amplifier carries out short-circuit protection test can accurately detect the output direct current of power amplifier, ensures the safety of power amplifier, and circuit structure is simple.
In order to achieve the purpose, the utility model adopts the following technical proposal:
the utility model provides a power amplifier output direct current monitoring circuit when power amplifier carries out short-circuit protection test which characterized in that: the power amplifier output direct current monitoring circuit comprises a first operational amplifier, a second operational amplifier and a single chip microcomputer of the power amplifier, wherein a negative input end pin of the first operational amplifier is connected with an input resistor connected in series, a positive phase signal output by the power amplifier is sent to the first operational amplifier through the input resistor connected in series, a positive input end pin of the first operational amplifier is connected with the input resistor connected in series, a positive input end pin of the first operational amplifier is further connected with a grounding capacitor and a grounding resistor, a feedback capacitor and a feedback resistor are connected between the negative input end pin of the first operational amplifier and an output end pin of the first operational amplifier and are connected in parallel, and an inverted phase signal output by the power amplifier passes through the input resistor and the grounding capacitor, A ground resistor to the first operational amplifier, the first operational amplifier performing a differential operation; the first operational amplifier is connected with the second operational amplifier through an RC filter; the output end pin of the second operational amplifier is connected to the single chip microcomputer through an isolation resistor and an input resistor of the single chip microcomputer, the direct current signal amplified by the second operational amplifier is subjected to direct current monitoring operation through the single chip microcomputer, the single chip microcomputer firstly sends out an instruction to enable PWM of an output stage of the power amplifier to close output according to detected output direct current of the power amplifier, and finally sends out an instruction to close a switching power supply to cut off power supply of the power amplifier.
The RC filter comprises a resistor connected in series and a grounded capacitor connected in parallel.
The negative electrode input end pin of the second operational amplifier is connected with a first resistor and a second resistor, the other end of the first resistor is grounded, the other end of the second resistor is connected with the output end pin of the second operational amplifier, and the first resistor and the second resistor form a proportional amplification resistor of the second operational amplifier.
The isolation resistor is connected with the 3.3V positive power supply through a third resistor, the isolation resistor is further connected with a first diode and a second diode, the anode of the first diode is connected with the cathode of the second diode, the anode of the second diode is grounded, the cathode of the first diode is connected with the 3.3V positive power supply, the third resistor is a power supply pull-up resistor, and the first diode and the second diode are pull-up diodes and used for pulling up level voltage of the single chip microcomputer.
The utility model discloses following beneficial effect has:
the utility model discloses owing to included first operational amplifier, the singlechip of second operational amplifier and amplifirer, the utilization uses first operational amplifier as the difference operational amplifier circuit that the core constitutes, and through the enlargeing of second operational amplifier, thereby the amplifirer is when carrying out the short-circuit protection test, detect the output direct current of amplifirer, and carry the singlechip with the output direct current of the amplifirer that detects, singlechip give-out order lets the PWM of amplifirer output level close the output, particularly, the singlechip carries out direct current monitoring operation, when detecting the amplifirer output direct current when positive and negative 1.5V, the singlechip sends out order to execution circuit earlier, let the PWM of amplifirer output level close the output. The power amplifier is when carrying out the short-circuit protection test, the utility model discloses can the accurate output direct current that detects the power amplifier, ensure the safety of power amplifier, circuit structure is simple.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below. It is obvious that the drawings described below are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be obtained from these drawings without inventive effort.
Fig. 1 is a schematic diagram of the structure of the output dc monitoring circuit of the power amplifier of the present invention.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings.
Wherein the showings are for the purpose of illustration only and are shown by way of illustration only and not in actual form, and are not to be construed as limiting the present patent; for a better understanding of the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not indicated or implied that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are used only for illustrative purposes and are not to be construed as limiting the present patent, and the specific meaning of the terms will be understood by those skilled in the art according to the specific circumstances.
As shown in fig. 1, the amplifier output dc monitoring circuit of the power amplifier of the present invention during short-circuit protection test is a power amplifier output dc monitoring circuit dedicated for use in the power amplifier protection circuit, and comprises a first operational amplifier IC1C, a second operational amplifier IC3B and a single chip of the power amplifier, wherein a negative input terminal pin of the first operational amplifier IC1C is connected with input resistors R206 and R205 connected in series, a positive phase signal output by the power amplifier is sent to the first operational amplifier IC1C through the input resistor connected in series, a positive input terminal pin of the first operational amplifier IC1C is connected with input resistors R208 and R207 connected in series, a positive input terminal pin of the first operational amplifier IC1C is further connected with a ground capacitor C99 and a ground resistor R203, a feedback capacitor C100 and a feedback resistor R204 are connected between the negative input terminal pin of the first operational amplifier IC1C and an output terminal of the first operational amplifier IC1C, and the feedback capacitor C100 and the feedback resistor R204 are connected in parallel, the inverted signal output by the power amplifier passes through input resistors R208 and R207, a grounded capacitor C99 and a grounded resistor R203 to a pin 10 of a first operational amplifier IC1C, and the first operational amplifier IC1C carries out differential operation; the first operational amplifier IC1C and the second operational amplifier IC3B are connected through an RC filter; the output end pin of the second operational amplifier IC3B is sent to the single chip microcomputer through the isolation resistor R215 and the input resistor R212 of the single chip microcomputer, the direct current signal amplified by the second operational amplifier IC3B is subjected to direct current monitoring operation by the single chip microcomputer, and the single chip microcomputer sends out an instruction according to the measured output direct current of the power amplifier to enable the PWM of the output stage of the power amplifier to be turned off for output. The feedback capacitor C100 is used for eliminating high-frequency interference, and the feedback resistor R204 is used for setting the amplification factor of the operational amplifier. The grounded capacitor C99 is used for eliminating interference, the first operational amplifier IC1C is used as a core to form a differential amplifier, and the value of the feedback resistor R204 divided by the value of R205+ R206 is the attenuation amplification factor of the circuit. The first operational amplifier IC1C is an operational chip TL072C by the company TI for outputting a sense attenuation amplifier.
The RC filter is mainly used for filtering noise interference. The RC filter comprises resistors R34 and R35 which are connected in series, and grounded capacitors C11 and C7 which are connected in parallel, wherein grounded capacitors C11 and C7 are connected in parallel at two ends of a resistor R35.
The pin of the negative input end of the second operational amplifier IC3B is connected with a first resistor R25 and a second resistor R30, the other end of the first resistor R25 is grounded, the other end of the second resistor R30 is connected with the pin of the output end of the second operational amplifier IC3B, and the first resistor R25 and the second resistor R30 form a proportional amplification resistor of the second operational amplifier IC 3B. The isolation resistor R215 is connected with a 3.3V positive power supply through a third resistor R213, the isolation resistor is further connected with a first diode and a second diode, the anode of the first diode is connected with the cathode of the second diode, the anode of the second diode is grounded, the cathode of the first diode is connected with the 3.3V positive power supply, the third resistor is a power supply pull-up resistor, and the first diode and the second diode are pull-up diodes and are used for pulling up a level voltage of the single chip microcomputer.
The singlechip is connected with the switching power supply part of the power amplifier, and has the function that the PWM closing output of the output stage of the power amplifier fails, and the singlechip immediately continues to send a direct current signal to the switching power supply part to enable the switching power supply part to close power supply, so that the power amplifier is ensured to have no direct current output.
It should be noted that the above embodiments are only preferred embodiments of the present invention and the technical principles applied, and any changes or substitutions which can be easily conceived by those skilled in the art within the technical scope of the present invention are also included in the protection scope of the present invention.
Claims (4)
1. The utility model provides a power amplifier output direct current monitoring circuit when power amplifier carries out short-circuit protection test which characterized in that: the power amplifier output direct current monitoring circuit comprises a first operational amplifier, a second operational amplifier and a single chip microcomputer of the power amplifier, wherein a negative input end pin of the first operational amplifier is connected with an input resistor connected in series, a positive phase signal output by the power amplifier is sent to the first operational amplifier through the input resistor connected in series, a positive input end pin of the first operational amplifier is connected with the input resistor connected in series, a positive input end pin of the first operational amplifier is further connected with a grounding capacitor and a grounding resistor, a feedback capacitor and a feedback resistor are connected between the negative input end pin of the first operational amplifier and an output end pin of the first operational amplifier and are connected in parallel, and an inverted phase signal output by the power amplifier passes through the input resistor and the grounding capacitor, A ground resistor to the first operational amplifier, the first operational amplifier performing a differential operation;
the first operational amplifier is connected with the second operational amplifier through an RC filter;
the output end pin of the second operational amplifier is connected to the single chip microcomputer through an isolation resistor and an input resistor of the single chip microcomputer, the direct current signal amplified by the second operational amplifier is subjected to direct current monitoring operation through the single chip microcomputer, the single chip microcomputer firstly sends out an instruction to enable PWM of an output stage of the power amplifier to close output according to detected output direct current of the power amplifier, and finally sends out an instruction to close a switching power supply to cut off power supply of the power amplifier.
2. The power amplifier output dc monitoring circuit when the power amplifier performs the short-circuit protection test according to claim 1, wherein: the RC filter comprises a resistor connected in series and a grounded capacitor connected in parallel.
3. The power amplifier output dc monitoring circuit when the power amplifier performs the short-circuit protection test according to claim 2, wherein: the negative electrode input end pin of the second operational amplifier is connected with a first resistor and a second resistor, the other end of the first resistor is grounded, the other end of the second resistor is connected with the output end pin of the second operational amplifier, and the first resistor and the second resistor form a proportional amplification resistor of the second operational amplifier.
4. The power amplifier output dc monitoring circuit when the power amplifier performs the short-circuit protection test according to claim 2, wherein: the isolation resistor is connected with the 3.3V positive power supply through a third resistor, the isolation resistor is further connected with a first diode and a second diode, the anode of the first diode is connected with the cathode of the second diode, the anode of the second diode is grounded, the cathode of the first diode is connected with the 3.3V positive power supply, the third resistor is a power supply pull-up resistor, and the first diode and the second diode are pull-up diodes and used for pulling up level voltage of the single chip microcomputer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920879720.8U CN209897011U (en) | 2019-06-12 | 2019-06-12 | Power amplifier output direct current monitoring circuit when power amplifier carries out short-circuit protection test |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920879720.8U CN209897011U (en) | 2019-06-12 | 2019-06-12 | Power amplifier output direct current monitoring circuit when power amplifier carries out short-circuit protection test |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN209897011U true CN209897011U (en) | 2020-01-03 |
Family
ID=69001511
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920879720.8U Expired - Fee Related CN209897011U (en) | 2019-06-12 | 2019-06-12 | Power amplifier output direct current monitoring circuit when power amplifier carries out short-circuit protection test |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN209897011U (en) |
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2019
- 2019-06-12 CN CN201920879720.8U patent/CN209897011U/en not_active Expired - Fee Related
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| Date | Code | Title | Description |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200103 |