A compensation circuit for microphone temperature drift adjustment
By setting capacitors C10 and C7 in the microphone circuit to balance the temperature drift of the transistor, the problem of reduced microphone output bias voltage under high temperature and high humidity conditions was solved, enabling the microphone to work normally under abnormal conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGLING MOTORS
- Filing Date
- 2025-08-01
- Publication Date
- 2026-07-21
AI Technical Summary
In high temperature and high humidity environments, the temperature drift of the microphone's transistors causes a decrease in the output bias voltage, resulting in a mechanical tone during calls.
In the microphone circuit, two capacitors C10 and C7 are connected in parallel between the input and emitter of transistor Q1, and the collector of transistor Q1 is grounded. The entire circuit is then connected to the microphone circuit, and the temperature drift effect is balanced through the feedback compensation circuit.
Maintain a stable output bias voltage for the microphone in high temperature and high humidity environments to ensure normal microphone operation.
Smart Images
Figure CN224538311U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of automobile manufacturing, specifically to a compensation circuit for adjusting microphone temperature drift. Background Technology
[0002] During the development of in-vehicle infotainment systems for overseas markets, a mechanical tone issue arose in an engineering vehicle in the Middle East, resulting in poor overall sound quality. After multiple checks, including audio capture and microphone replacement, and simulations of high temperature and humidity in an environmental simulation chamber, it was confirmed that microphones suitable for domestic use would exhibit the same problem in this scenario, given the high temperatures in the region. Further verification revealed that the issue stemmed from the amplifier (transistor) within the circuit board. Under high temperature and humidity conditions (85℃, 85% humidity), the transistor experienced temperature drift, leading to a decrease in output bias voltage. This resulted in waveform clipping (mechanical tone during calls), ultimately causing the system to malfunction. Utility Model Content
[0003] To address the aforementioned problems, this invention proposes a compensation circuit for microphone temperature drift adjustment. Based on this compensation circuit, the temperature drift effect of the transistor is balanced. The specific technical solution is as follows: A compensation circuit for adjusting microphone temperature drift is provided. A transistor Q1 is provided on the microphone circuit. Two capacitors C10 and C7 are connected in parallel between the base and emitter of the input terminal of the transistor Q1. The emitter of the transistor Q1 is connected to the output terminal, and the collector of the transistor Q1 is grounded. The input terminal, output terminal and ground terminal of the transistor Q1 are connected to the microphone circuit as a whole.
[0004] This invention uses a feedback compensation circuit to balance the temperature drift effect of the transistor and maintain a stable output bias voltage, thereby ensuring that the microphone works normally under abnormal conditions. Attached Figure Description
[0005] Figure 1 A microphone circuit incorporating the compensation circuit of this invention. Detailed Implementation
[0006] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0007] This invention adds a compensation circuit to the microphone circuit to balance the effect of transistor temperature drift, thus enabling the microphone to function normally even in high temperature and high humidity environments (85℃, 85% humidity). The specific compensation circuit is as follows. Figure 1As shown, a compensation circuit for adjusting microphone temperature drift is provided. A transistor Q1 is provided on the microphone circuit. Two capacitors C10 and C7 are connected in parallel between the base and emitter of the input terminal of the transistor Q1. The emitter of the transistor Q1 is connected to the output terminal, and the collector of the transistor Q1 is grounded. The input terminal, output terminal and ground terminal of the transistor Q1 are connected to the microphone circuit as a whole.
[0008] The preferred embodiments of this patent have been described in detail above. However, this patent is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this patent.
Claims
1. A compensation circuit for microphone temperature drift adjustment, characterized in that: The microphone circuit includes a transistor Q1. Two capacitors, C10 and C7, are connected in parallel between the base and emitter of the transistor Q1. The emitter of the transistor Q1 is connected to the output terminal, and the collector of the transistor Q1 is grounded. The input, output, and ground terminals of the transistor Q1 are all connected to the microphone circuit.