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1. (WO2017034837) RAIL-TO-RAIL INPUT STAGE CIRCUIT WITH CONSTANT TRANSCONDUCTANCE

Pub. No.:    WO/2017/034837    International Application No.:    PCT/US2016/046918
Publication Date: Fri Mar 03 00:59:59 CET 2017 International Filing Date: Sat Aug 13 01:59:59 CEST 2016
IPC: H03F 3/45
Applicants: QUALCOMM INCORPORATED
Inventors: SHEN, Liangguo
SHI, Chunlei
GUAN, Hua
Title: RAIL-TO-RAIL INPUT STAGE CIRCUIT WITH CONSTANT TRANSCONDUCTANCE
Abstract:
Embodiments described herein relate to an improved circuit technique in a rail-to-rail input stage circuit utilizing non-complementary differental pairs with bias control designed to maintain a constant transconductance "gm" throughout an input common mode voltage range. The rail-to-rail input stage circuit comprises a first differential pair circuit, a level-shifted differential pair circuit coupled with the first differential pair circuit, and a constant transconductance generation circuit coupled with the level-shifted differential pair circuit. The constant transconductance generation circuit is configured to control the bias current conducting in the level-shifted differential pair circuit based on current conducting in the first differential pair circuit to maintain a constant transconductance in the rail-to-rail input stage circuit.