A vehicle-mounted audio power amplifier nonlinear temperature drift dynamic bias detection circuit

Abstract

The utility model belongs to detection circuit technical field relates to a kind of nonlinear temperature drift dynamic bias detection circuit of vehicle-mounted audio power amplifier, including PTAT circuit, NTC circuit, A2B bus, difference operational amplifier circuit, voltage divider network, audio signal amplification circuit and its connection relationship.The utility model carries out mixed temperature detection by integration PTAT circuit and NTC circuit, then carry out difference design to eliminate non-linear error, generate compensation voltage V comp , temperature sampling of multiple temperature nodes is triggered by A2B bus protocol synchronization signal, temperature sampling and audio data time domain alignment are realized, and compensation voltage V comp It is injected into the voltage divider network of MP7722DF power amplifier chip REF pin, and bias voltage dynamic detection is realized.

Description

Technical Field

[0001] This utility model relates to the field of detection circuit technology, and in particular to a nonlinear temperature drift dynamic bias detection circuit for vehicle audio power amplifiers. Background Technology

[0002] Car audio amplifiers are a key component of modern car audio systems, and their performance directly affects the fidelity of audio playback and the user experience. With the development of electric vehicles, the requirements for the stability of car audio systems in a wide temperature range are becoming increasingly stringent, especially in the extreme temperature range of -40℃ to 80℃, ensuring the stable operation of audio amplifiers has become a technical challenge. Class D audio amplifiers, as the core component of mainstream car audio systems, are prone to nonlinear temperature drift in their input stage bias voltage over a wide temperature range. This leads to fluctuations in the on-resistance of the output stage MOSFET amplifier transistors, causing audio distortion and reduced efficiency. Utility Model Content

[0003] The purpose of this invention is to solve the technical problems existing in the background art. To this end, a nonlinear temperature drift dynamic bias detection circuit for vehicle audio power amplifiers is provided.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] A nonlinear temperature drift dynamic bias detection circuit for an in-vehicle audio power amplifier includes multiple temperature nodes set on the in-vehicle audio equipment. Each temperature node is equipped with a hybrid temperature detection circuit, and the hybrid temperature detection circuits of each temperature node are connected to each other via an A2B bus.

[0006] The hybrid temperature detection circuit includes a PTAT circuit and an NTC circuit. The output terminals of the PTAT circuit and the NTC circuit are respectively connected to the two input terminals of a differential operational amplifier circuit. The output terminal of the differential operational amplifier circuit outputs a compensation voltage V. comp The compensation voltage V comp It is connected to the audio signal amplification circuit through a voltage divider network.

[0007] The following is a further defined technical solution of this utility model: the PTAT circuit includes MOS transistors M1, M2, and M3 and transistors Q1 and Q2;

[0008] The sources of the three MOS transistors M1, M2, and M3 are all connected to voltage VDD.

[0009] The drain of the MOS transistor M1 is connected to the emitter of the transistor Q1. The base and collector of the transistor Q1 are both grounded. The drain of the MOS transistor M2 is connected to the emitter of the transistor Q2 through a resistor R1. The base and collector of the transistor Q2 are both grounded. The drain of the MOS transistor M3 serves as the output terminal of the PTAT circuit.

[0010] The gates of the three MOS transistors M1, M2, and M3 are all interconnected and electrically connected to the output terminal of the operational amplifier U0. The drain of the MOS transistor M1 is connected to the inverting input terminal of the operational amplifier U0, and the drain of the MOS transistor M2 is connected to the non-inverting input terminal of the operational amplifier U0.

[0011] The following is a further defined technical solution of this utility model: the NTC circuit includes an NTC thermistor and a resistor R. fix Resistors R2 and R3, capacitor C1, and operational amplifier U1;

[0012] The resistor R fix One end of the amplifier is connected to voltage VCC, and the other end is connected to one end of an NTC thermistor. The other end of the NTC thermistor is connected to GND. A capacitor C1 is connected in parallel across the two ends of the NTC thermistor. The non-inverting input of the operational amplifier is connected to resistor R. fix On the line between the operational amplifier U1 and the NTC thermistor, the inverting input terminal of the operational amplifier U1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the GND terminal. The inverting input terminal and the output terminal of the operational amplifier U1 are electrically connected to the resistor R3. The output terminal of the operational amplifier U1 serves as the output terminal of the NTC circuit.

[0013] The following is a further defined technical solution of this utility model: the voltage divider network includes resistors R4, R5, R6 and capacitor C20;

[0014] One end of resistor R4 is connected to a compensation voltage V comp The other end of resistor R4 is connected to one end of capacitor C20, and the other end of capacitor C20 is connected to GND.

[0015] One end of resistor R5 is connected to voltage VDD, and the other end of resistor R5 is connected to one end of resistor R6, and the other end of resistor R6 is connected to GND.

[0016] The line between resistor R4 and capacitor is connected to the line between resistors R5 and R6 and is connected to the REF1 pin of the audio signal amplifier circuit.

[0017] Compared with the prior art, the present invention has the following technical effects:

[0018] This invention integrates PTAT and NTC circuits for hybrid temperature detection, then uses differential design to eliminate nonlinear errors and generate a compensation voltage V. comp Temperature sampling at multiple temperature nodes is triggered by a synchronization signal via the A2B bus protocol, achieving time-domain alignment between temperature sampling and audio data, and the compensation voltage V is applied. comp A voltage divider network is injected into the REF pin of the MP7722DF power amplifier chip to achieve dynamic detection of the bias voltage.

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a diagram showing the connection relationships of the relevant circuits in this utility model;

[0022] Figure 2 This is a connection diagram of the PTAT circuit in this utility model;

[0023] Figure 3 This is a connection diagram of the NTC circuit in this utility model;

[0024] Figure 4 This is a connection diagram of the audio signal amplifier circuit with a voltage divider network in this utility model. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0026] like Figure 1As shown, this embodiment provides a nonlinear temperature drift dynamic bias detection circuit for an in-vehicle audio power amplifier. It includes multiple temperature nodes disposed on the in-vehicle audio equipment. Each temperature node is equipped with a hybrid temperature detection circuit, and these hybrid temperature detection circuits are connected to each other via an A2B bus. The hybrid temperature detection circuit includes a PTAT circuit and an NTC circuit. The output terminals of the PTAT circuit and the NTC circuit are respectively connected to the two input terminals of a differential operational amplifier circuit (i.e., a differential operational amplifier). The output terminal of the differential operational amplifier circuit outputs a compensation voltage V. comp A PTAT+NTC hybrid temperature sensor is used, and a compensation voltage V is generated via a differential operational amplifier circuit. comp Temperature sampling at multiple temperature nodes is triggered by a synchronization signal via the A2B bus protocol, achieving time-domain alignment between temperature sampling and audio data, and compensating voltage V. comp A voltage divider network is injected into the REF pin of the MP7722DF power amplifier chip in the audio signal amplification circuit to achieve dynamic detection of the bias voltage. Then, based on the THD detection value output by the MP7722DF power amplifier chip in the audio signal amplification circuit, the gain parameters of the PTAT circuit and the NTC circuit are dynamically adjusted to form a closed-loop feedback.

[0027] like Figure 2 As shown, the PTAT circuit mainly consists of MOSFETs M1, M2, and M3, and transistors Q1 and Q2. The PTAT circuit utilizes the thermoelectric characteristics of transistors Q1 and Q2 to detect temperature changes. Specifically, the sources of MOSFETs M1, M2, and M3 are all connected to voltage VDD; the drain of MOSFET M1 is connected to the emitter of transistor Q1, and the base and collector of transistor Q1 are grounded; the drain of MOSFET M2 is connected to the emitter of transistor Q2 through resistor R1, and the base and collector of transistor Q2 are grounded; the drain of MOSFET M3 serves as the output of the PTAT circuit; the gates of MOSFETs M1, M2, and M3 are interconnected and electrically connected to the output of operational amplifier U0; the drain of MOSFET M1 is connected to the inverting input of operational amplifier U0, and the drain of MOSFET M2 is connected to the non-inverting input of operational amplifier U0. A current mirror is constructed using MOSFETs M1, M2, and M3 and transistors Q1 and Q2 with an emitter area ratio of n. The temperature drift slope is matched by adjusting the resistance value of R1.

[0028] like Figure 3 As shown, the NTC circuit mainly consists of an NTC thermistor and a resistor R. fix The circuit consists of resistors R2 and R3, capacitor C1, and operational amplifier U1. The NTC circuit uses an NTC thermistor with a B value of 3950 to detect temperature changes. The specific circuit is as follows: Resistor R... fixOne end of the amplifier is connected to voltage VCC, and the other end is connected to one end of an NTC thermistor. The other end of the NTC thermistor is connected to GND. A capacitor C1 is connected in parallel across the two ends of the NTC thermistor. The non-inverting input of operational amplifier U1 is connected to resistor R. fix In the circuit between the operational amplifier U1 and the NTC thermistor, the inverting input terminal of the operational amplifier U1 is connected to one end of resistor R2, and the other end of resistor R2 is connected to GND. Resistor R3 is electrically connected between the inverting input terminal and the output terminal of the operational amplifier U1. The output terminal of the operational amplifier U1 serves as the output terminal of the NTC circuit. Resistors R2 and R3 adjust the amplification factor of VNTC.

[0029] like Figure 4 As shown, the voltage divider network mainly consists of resistors R4, R5, R6, and capacitor C20. The audio signal amplification circuit mainly includes the MP7722DF single-supply Class D stereo power amplifier (abbreviated as MP7722 power amplifier chip). One end of resistor R4 is connected to the compensation voltage V. comp (Right now Figure 4 V in REF1 The other end of resistor R4 is connected to one end of capacitor C20, and the other end of capacitor C20 is connected to GND. One end of resistor R5 is connected to voltage VDD, and the other end of resistor R5 is connected to one end of resistor R6, and the other end of resistor R6 is connected to GND. The line between resistor R4 and capacitor is connected to the line between resistor R5 and resistor R6 and connected to the REF pin of MP7722 power amplifier chip.

[0030]

[0031] The value of K is adjusted by resistors R4, R5, and R6.

[0032] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any way. Any person skilled in the art can make many possible variations and modifications to the technical solution of this utility model using the disclosed methods and techniques, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of this utility model. Therefore, all equivalent changes made based on the shape, structure, and principle of this utility model without departing from its technical solution should be covered within the protection scope of this utility model.

Claims

1. A nonlinear temperature drift dynamic bias detection circuit for a vehicle-mounted audio power amplifier, characterized in that, It includes multiple temperature nodes installed on the vehicle audio equipment, each temperature node is equipped with a hybrid temperature detection circuit, and the hybrid temperature detection circuits of each temperature node are connected to each other via an A2B bus. The hybrid temperature detection circuit includes a PTAT circuit and an NTC circuit. The output terminals of the PTAT circuit and the NTC circuit are respectively connected to the two input terminals of a differential operational amplifier circuit. The output terminal of the differential operational amplifier circuit outputs a compensation voltage V. comp The compensation voltage V comp It is connected to the audio signal amplification circuit through a voltage divider network.

2. The nonlinear temperature drift dynamic bias detection circuit for a vehicle-mounted audio power amplifier as described in claim 1, characterized in that, The PTAT circuit includes MOS transistors M1, M2, and M3, and transistors Q1 and Q2; The sources of the three MOS transistors M1, M2, and M3 are all connected to voltage VDD. The drain of MOS transistor M1 is connected to the emitter of transistor Q1, and the base and collector of transistor Q1 are both grounded; the drain of MOS transistor M2 is connected to the emitter of transistor Q2 through resistor R1, and the base and collector of transistor Q2 are both grounded; the drain of MOS transistor M3 serves as the output terminal of the PTAT circuit. The gates of the three MOS transistors M1, M2, and M3 are all interconnected and electrically connected to the output terminal of the operational amplifier U0. The drain of the MOS transistor M1 is connected to the inverting input terminal of the operational amplifier U0, and the drain of the MOS transistor M2 is connected to the non-inverting input terminal of the operational amplifier U0.

3. The nonlinear temperature drift dynamic bias detection circuit for a vehicle-mounted audio power amplifier as described in claim 1, characterized in that, The NTC circuit includes an NTC thermistor and a resistor R. fix Resistors R2 and R3, capacitor C1, and operational amplifier U1; The resistor R fix One end of the amplifier is connected to voltage VCC, and the other end is connected to one end of an NTC thermistor. The other end of the NTC thermistor is connected to GND. A capacitor C1 is connected in parallel across the two ends of the NTC thermistor. The non-inverting input of the operational amplifier U1 is connected to resistor R. fix On the line between the operational amplifier U1 and the NTC thermistor, the inverting input terminal of the operational amplifier U1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the GND terminal. The inverting input terminal and the output terminal of the operational amplifier U1 are electrically connected to the resistor R3. The output terminal of the operational amplifier U1 serves as the output terminal of the NTC circuit.

4. The nonlinear temperature drift dynamic bias detection circuit for a vehicle-mounted audio power amplifier as described in claim 1, characterized in that, The voltage divider network includes resistors R4, R5, R6 and capacitor C20; One end of resistor R4 is connected to a compensation voltage V comp1 The other end of resistor R4 is connected to one end of capacitor C20, and the other end of capacitor C20 is connected to GND. One end of resistor R5 is connected to voltage VDD, and the other end of resistor R5 is connected to one end of resistor R6, and the other end of resistor R6 is connected to GND. The line between resistor R4 and capacitor C20 is connected to the line between resistors R5 and R6 and is connected to the REF1 pin of the audio signal amplifier circuit.

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