A silicon microphone and an application-specific integrated circuit therein

Abstract

The invention provides a silicon microphone and a special integrated circuit used in the silicon microphone. The silicon microphone comprises a charge pump, wherein the charge pump comprises a first boosted circuit, a second boosted circuit, a first diode and a second diode; each boosted circuit comprises N levels of boosted units; the output end of the previous level of boosted unit is connected with the input end of the rear level of boosted unit in two adjacent levels of boosted units of each boosted circuit; the first control end of the first boosted circuit and the second control end of the second boosted circuit are connected with a first clock signal; the second control end of the first boosted circuit and the first control end of the second boosted circuit are connected with a second clock signal; the first diode is connected between the output end of the first boosted circuit and the output end of the charge pump; the second diode is connected between the output end of the second boosted circuit and the output end of the charge pump. Compared with the prior art, the special integrated circuit can be used for effectively restraining the noise of the charge pump, and thus the signal to noise ratio of the silicon microphone is improved.

Description

[0001] 【Technical field】 [0002] The invention relates to the field of circuit design, in particular to a silicon microphone and an application-specific integrated circuit therein. [0003] 【Background technique】 [0004] At present, the widely used microphones include traditional electret condenser microphones and emerging silicon microphones (also known as miniature silicon-based microphones). Compared with electret condenser microphones, silicon microphones have the advantages of small size, insensitivity to the environment, no need for high bias voltage, and strong shock resistance, which makes silicon microphones occupy a large share in portable digital products. The big advantage, and as the price drops, silicon microphones are gradually replacing electret condenser microphones. [0005] Please refer to figure 1 As shown, it is a schematic circuit diagram of a silicon microphone in the prior art. The silicon microphone includes a micro-electromechanical system (Micro-...

AI Technical Summary

Problems solved by technology

Such a structure has two disadvantages: one is that a part of the high-frequency component will still be superimposed on the final DC voltage, and this becomes the main part of the charge pump noise added to the entire microphone system, which affects the signal-to-noise ratio of the silicon microphone Second, in order to achieve the ideal filtering characteristics, the low-pass filter 126 often needs to integrate a relatively large capacitor (usually between 20pF and 50pF) on the ASIC chip 120, thereby increasing the cost of the ASIC chip 120

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