A Reference Noise Rejected Current Mirror with a Fast Start-up Mechanism

P.-U. Su (Taiwan)

Keywords

Current mirror, fast startup, noise suppression, voltage controlled oscillator (VCO).

Abstract

A reference noise rejected current mirror with a fast start up mechanism is proposed in this paper. A very low frequency pole, which is 7.2-kHz in this design, can be implemented at the bias circuit so that noise coming from bias generating circuits can be heavily filtered. A fast start-up mechanism by moving that 7.2-kHz pole to a much higher frequency is also proposed to speed up its turn-on process. This fast start-up mechanism reduces the start-up time from more than 100-µs to 0.2-µs, and it consumes no steady current after start-up. Simulations show that the proposed circuit can reject the reference noise significantly, ease the noise design of the reference generating circuit, consume no DC current in operation, achieve a fast start-up, and occupy a small chip area.

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