Microphone programmable gain amplifier integrated circuit

Abstract

The invention discloses a microphone programmable gain amplifier integrated circuit, relates to the field of voice integrated circuits, the circuit comprises an operational amplifier, two groups of first capacitors, two groups of second capacitors, two groups of third capacitors and a switched capacitor array, a small-capacity first capacitor for decoupling is connected in series to the differential input end of the operational amplifier, and two second capacitors are respectively bridged between the differential input end and the differential output end of the operational amplifier; the switched capacitor array comprises a plurality of groups of first switches and fourth capacitors which are connected in series, and the fourth capacitors are gated and controlled by the first switches to be connected with the second capacitors or the first capacitors in parallel to form programmable gain; the third capacitor is connected with a second switch in series, the second switch is switched andconnected at a clock frequency, in a first half period of the clock frequency, the third capacitor is gated by the second switch, and two ends of the third capacitor are respectively connected with the input common-mode voltage and the output common-mode voltage; and in the second half period of the clock frequency, the third capacitor is connected with the second capacitor in parallel.

Description

technical field [0001] The invention relates to the field of voice integrated circuits, in particular to a microphone programmable gain amplifier integrated circuit. Background technique [0002] In mobile communication electronic equipment, circuit scale and chip area are important considerations in design. In the mobile phone system, reducing the effective area of ​​each chip on the motherboard not only means that the required cost is reduced, but also means that more chips can be added to the printed circuit board with the same area to enrich the system functions. In traditional mobile phone motherboards, passive surface-mount devices represented by resistors, capacitors, and inductors occupy a large amount of system area in the form of direct soldering. In recent years, thanks to the SIP (System In a Package) system-in-package technology, engineers can package these passive devices and chips in a package. However, in the path from the microphone to the analog front-end...

AI Technical Summary

Problems solved by technology

However, in the path from the microphone to the analog front-end amplifier, large decoupling capacitors are often required, and these large-capacity capacitors are difficult to implement in SIP packaging due to their large area.

A typical microphone-to-programmable amplifier needs to use an off-chip decoupling capacitor to eliminate the DC component in the microphone. The capacitance value of the decoupling capacitor generally ranges from a few hundred nanofarads to several microfarads, which cannot be integrated on-chip.

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