公开(公告)号：US20150071466A1

公开(公告)日：2015-03-12

申请号：US14448848

申请日：2014-07-31

Applicant: Wolfson Microelectronics plc

Inventor： Jean Pierre Lasseuguette ,  James Deas

IPC: H03F3/183 ,  H04R23/00 ,  H03F3/45

CPC classification number: H03F3/183 ,  H03F1/0266 ,  H03F1/3205 ,  H03F1/3211 ,  H03F3/185 ,  H03F3/187 ,  H03F3/45071 ,  H03F3/45183 ,  H03F3/45188 ,  H03F3/45197 ,  H03F3/45654 ,  H03F2200/03 ,  H03F2200/78 ,  H03F2203/45112 ,  H03F2203/45244 ,  H03F2203/45392 ,  H03F2203/45396 ,  H03F2203/45418 ,  H03F2203/45424 ,  H03F2203/45498 ,  H03F2203/45658 ,  H04R3/00 ,  H04R19/005 ,  H04R19/04 ,  H04R23/00 ,  H04R2201/003

Abstract: Amplifier arrangements for read-out of MEMS capacitive transducers, such as low-noise amplifiers. An amplifier circuit has first and second MOS transistors, with the gate of the first transistor driven by the input signal, and the gate of the second transistor driven by a reference. The sources of the first and second transistors are connected via an impedance. Modulation circuitry is arranged to monitor a signal with a value that varies with the input signal and to modulate the back-bias voltage between the bulk and source terminals of the first and second transistors with the applied modulation being equal for each transistor and based on said monitored signal. The back-bias of the first transistor can be increase to extend the input range of the transistor in situations where the input signal may otherwise result in signal clipping, while avoiding noise and power issues for other input signal levels. By applying an equal modulation to the back-bias of each transistor, there is no substantial modulation of the output signal.

Abstract translation: 用于读取MEMS电容式换能器（如低噪声放大器）的放大器装置。 放大器电路具有第一和第二MOS晶体管，第一晶体管的栅极由输入信号驱动，第二晶体管的栅极由参考电压驱动。 第一和第二晶体管的源极通过阻抗连接。 调制电路被布置为以具有随输入信号变化的值来监测信号，并且调制第一和第二晶体管的体源极和源极端之间的反向偏置电压，并且对于每个晶体管，施加的调制相等，并且基于所述 监控信号。 在输入信号可能导致信号削波的情况下，可以增加第一晶体管的反偏压以延长晶体管的输入范围，同时避免其他输入信号电平的噪声和功率问题。 通过对每个晶体管的反向偏置施加相等的调制，对输出信号没有实质的调制。