CN-224216846-U - Battery voltage detection circuit, vehicle-mounted power amplifier and vehicle-mounted video and audio system

Abstract

The application discloses a battery voltage detection circuit, a vehicle-mounted power amplifier and a vehicle-mounted video and audio system, wherein the battery voltage detection circuit comprises an operational amplifier and a voltage stabilizing chip-level analog-to-digital converter ADC module, the stable constant current source is provided for the voltage stabilizing chip through the operational amplifier, so that the voltage stabilizing chip can output stable reference voltage to the ADC module. On the other hand, the ADC module samples the battery voltage, and then the actual value of the battery voltage can be obtained based on the sampled battery voltage and the reference voltage. According to the application, the stable constant current source is provided for the voltage stabilizing chip through the operational amplifier, and the voltage stabilizing chip is supported to output stable reference voltage, so that compared with the reference voltage in the MCU, the voltage stabilizing chip is not easily influenced by factors such as temperature, power supply noise and aging in a vehicle-mounted environment, and the drift of the reference voltage is reduced, so that the accuracy of a battery voltage detection result is improved.

Inventors

• LI HU
• WANG TAO
• Hui Kangxiang

Assignees

• 科大讯飞(苏州)科技有限公司

Dates

Publication Date

20260508

Application Date

20250418

Claims (10)

1. 1. A battery voltage detection circuit, comprising: the analog-to-digital converter comprises an operational amplifier, a voltage stabilizing chip and an analog-to-digital converter ADC module; The operational amplifier provides a constant current source for the voltage stabilizing chip, so that the voltage stabilizing chip outputs a reference voltage to the ADC module under the action of the constant current source; And the ADC module samples the battery voltage and obtains the actual value of the battery voltage based on the sampled battery voltage and the reference voltage.
2. 2. The battery voltage detection circuit according to claim 1, wherein the output end of the operational amplifier is grounded through a fourth resistor R4, the cathode and the anode of the voltage stabilizing chip in sequence, and the reference electrode of the voltage stabilizing chip is connected with the cathode and the positive input end of the operational amplifier respectively.
3. 3. The battery voltage detection circuit of claim 2, wherein a cathode of the voltage stabilizing chip is connected to the ADC module for outputting the reference voltage to the ADC module.
4. 4. The battery voltage detection circuit according to claim 2, wherein a positive input terminal of the operational amplifier is connected to a power supply vcc+ through a sixth resistor R6, and a negative input terminal of the operational amplifier is grounded through a fifth resistor R5.
5. 5. The battery voltage detection circuit according to claim 4, wherein an output terminal of the operational amplifier is connected to the negative input terminal through a third resistor R3.
6. 6. The battery voltage detection circuit of claim 1, further comprising a resistor divider network, wherein the resistor divider network comprises a first resistor R1 and a second resistor R2 which are connected in series, and one end of the resistor divider network is connected with the other end of the battery and grounded; the ADC module samples the battery voltage through the resistor divider network.
7. 7. The battery voltage detection circuit according to claim 1, wherein the ADC module is built in a micro control unit MCU, and an output end of the voltage stabilizing chip is connected to the MCU, so as to transmit the reference voltage to the ADC module through the MCU.
8. 8. The battery voltage detection circuit according to any one of claims 1 to 7, wherein the voltage stabilizing chip employs a three-terminal adjustable voltage reference chip AZ431.
9. 9. A vehicle-mounted power amplifier, comprising a power module and the battery voltage detection circuit of any one of claims 1-8, wherein the battery voltage detection circuit is configured to perform voltage detection on the power module.
10. 10. A vehicle-mounted audio-visual system comprising the vehicle-mounted power amplifier of claim 9.

Description

Battery voltage detection circuit, vehicle-mounted power amplifier and vehicle-mounted video and audio system Technical Field The application relates to the technical field of electronic circuits, in particular to a battery voltage detection circuit, a vehicle-mounted power amplifier and a vehicle-mounted video and audio system. Background Under the background of popularization of intelligent electric automobiles and high-end vehicle-mounted video and audio systems, the power density and dynamic response requirements of a vehicle-mounted power amplifier (simply called a vehicle-mounted power amplifier) are remarkably improved. The power supply voltage range of the vehicle-mounted power amplifier generally covers 9-16V, and voltage fluctuation directly influences the output efficiency, THD (total harmonic distortion) and thermal stability of the vehicle-mounted power amplifier. On-board power amplifiers are typically battery powered, and therefore accurate detection of battery voltage to guide battery management is necessary. The traditional scheme carries out voltage detection through an analog-to-digital converter ADC built in a micro control unit MCU. This approach relies on the stability of the reference voltage (e.g., AVDD) inside the MCU, but the reference voltage is susceptible to temperature, power noise and aging in the vehicle environment, resulting in reference voltage drift, and eventually, battery voltage detection error amplification. Disclosure of utility model In view of the above problems, the present application is provided to provide a battery voltage detection circuit, a vehicle-mounted power amplifier and a vehicle-mounted audio/video system, so as to improve the accuracy of the battery voltage detection result. The specific scheme is as follows: In a first aspect, there is provided a battery voltage detection circuit comprising: the analog-to-digital converter comprises an operational amplifier, a voltage stabilizing chip and an analog-to-digital converter ADC module; The operational amplifier provides a constant current source for the voltage stabilizing chip, so that the voltage stabilizing chip outputs a reference voltage to the ADC module under the action of the constant current source; And the ADC module samples the battery voltage and obtains the actual value of the battery voltage based on the sampled battery voltage and the reference voltage. In another implementation manner of the first aspect of the embodiment of the present application, an output terminal of the operational amplifier is grounded through a fourth resistor R4, a cathode and an anode of the voltage stabilizing chip in sequence, and a reference electrode of the voltage stabilizing chip is connected to the cathode and a positive input terminal of the operational amplifier, respectively. In another implementation manner of the first aspect of the embodiment of the present application, the cathode of the voltage stabilizing chip is connected to the ADC module and is configured to output the reference voltage to the ADC module. In a possible design, in another implementation manner of the first aspect of the embodiment of the present application, the positive input terminal of the operational amplifier is connected to the power supply vcc+ through the sixth resistor R6, and the negative input terminal of the operational amplifier is grounded through the fifth resistor R5. In a possible design, in another implementation manner of the first aspect of the embodiment of the present application, an output terminal of the operational amplifier is connected to the negative input terminal through a third resistor R3. In another implementation manner of the first aspect of the embodiment of the present application, the device further includes a resistor voltage-dividing network, where the resistor voltage-dividing network includes a first resistor R1 and a second resistor R2 connected in series, and one end of the resistor voltage-dividing network is connected to the other end of the battery and grounded; the ADC module samples the battery voltage through the resistor divider network. In another implementation manner of the first aspect of the embodiment of the present application, the ADC module is built in a micro control unit MCU, and an output end of the voltage stabilizing chip is connected to the MCU, so as to transmit the reference voltage to the ADC module through the MCU. In another implementation manner of the first aspect of the embodiment of the present application, the voltage stabilizing chip uses a three-terminal adjustable voltage reference chip AZ431. In a second aspect, there is provided a vehicle-mounted power amplifier, comprising a power module and the battery voltage detection circuit described in any one of the first aspects, wherein the battery voltage detection circuit is configured to perform voltage detection on the power module. In a third aspect, there is provided a vehicle-mounted audio-visual sy