Microphone amplification circuit design method and microphone amplification circuit

Abstract

The invention provides a microphone amplification circuit design method, which comprises the following steps of: arranging a layer of underlying metal between a substrate and a bonding pad of an integrated circuit, forming a first parasitic capacitance between the bonding pad and the underlying metal, and forming a second parasitic capacitance between the underlying metal and the substrate; searching a circuit point in the amplifying circuit, and enabling the circuit point to meet a preset condition; connecting the bottom layer metal to the circuit point, and connecting the bonding pad to the input end; the microphone is welded to a bonding pad of the integrated circuit to serve as a microphone capacitor, one end of the microphone capacitor is connected to the high-voltage bias voltage, and the other end of the microphone capacitor is connected to the input end; one end of the first parasitic capacitor is connected to the input end, and the other end is connected to the output end; one end of the second parasitic capacitor is connected to the output end and the other end is grounded. The invention further provides a microphone amplifying circuit. Compared with the prior art, the microphone amplification circuit design method and the microphone amplification circuit are higher in signal-to-noise ratio and better in performance.

Description

technical field [0001] The invention relates to the field of microphone amplifier circuits, in particular to a microphone amplifier circuit design method and microphone amplifier circuit for eliminating the influence of pad parasitic capacitance on signal-to-noise ratio. Background technique [0002] With the development of mobile communication technology, mobile terminals such as mobile phones, PADs, and notebook computers have gradually become indispensable electronic products in life. For these electronic products, the built-in microphone is used as a sound pickup unit, and the signal-to-noise ratio when the picked-up signal is output by the microphone amplifier circuit is an important evaluation index for product performance. [0003] In the related art microphone amplifier circuit, such as figure 1 As shown, the microphone is soldered to the microphone amplifier circuit of the integrated circuit through the pad, and the pad parasitic capacitance C is formed between the...

AI Technical Summary

Problems solved by technology

Amplifier M1' has circuit noise, pad parasitic capacitance C PAD ’The voltage division causes the input signal to become smaller, which leads to the output V of the microphone amplifier circuit Out ’ becomes smaller, especially when the microphone’s microphone capacitance C Mic ’ is relatively small, the voltage division is more significant, and the signal-to-noise ratio decreases more significantly, which makes the performance of the microphone amplifier circuit poor

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