Patent ID: 9723405
Date: 2017-08-01
CPC Classifications: H03F,H03G,H03H,H04R

Claim:
1. Apparatus for switchable attenuation of a differential input signal from a microphone, comprising: a positive attenuating path including a first n-type MOSFET having a drain connected to a source of a first p-type MOSFET; a negative attenuating path including a second n-type MOSFET having a drain connected to a source of a second p-type MOSFET; an attenuator to provide attenuation in the positive and negative attenuating paths; a positive non-attenuating path including a third n-type MOSFET having a drain connected to a source of a third p-type MOSFET; a negative non-attenuating path including a fourth n-type MOSFET having a drain connected to a source of a fourth p-type MOSFET; and a gate driver configured to: apply a first drive signal to a respective gate of each of the first n-type MOSFET, the second n-type MOSFET, the third p-type MOSFET, and the fourth p-type MOSFET, and apply a second drive signal of opposite polarity to the first drive signal to a respective gate of each of the first p-type MOSFET, the second p-type MOSFET, the third n-type MOSFET, and the fourth n-type MOSFET.