Low output impedance, low power buffer

摘要

A complementary push-pull buffer includes complementary transconductance (GM) devices connected as source-followers to drive a load. Current flowing through the GM devices is split, on the source side, between constant-current source circuitry and a push signal current multiplier (e.g., a current mirror) and, on the sink side, between constant-current sink circuitry and a pull signal current multiplier. The devices used to implement the constant-current circuits and the current multipliers are sized such that the current multipliers provide low output impedance, while the current splitting provides low overall power consumption.

主权项

1. A buffer circuit, comprising:
first main transconductance circuitry connected to convert an input signal into an output signal at an output node of the buffer circuit; first constant-current circuitry, connected in series with the first main transconductance circuitry, configured to generate a first constant current; and first current-multiplier circuitry connected to the first main transconductance circuitry and to the first constant-current circuitry such that current flowing through the first main transconductance circuitry is split between (i) the first constant current flowing through the first constant-current circuitry and (ii) first remaining current applied to the first current-multiplier circuitry, wherein the first current-multiplier circuitry comprises current-mirror circuitry that includes two or more cascaded current mirrors.