Patent ID: 6064257
Filing Date: 2000-05-16
Classification: H03B,H03F

Abstract:
A chopper-stabilized operational amplifier implemented on a single integrated circuit chip comprising:an operational amplifier on said chip;a chopper-stabilizer circuit on said chip auxiliary to the operational amplifier, wherein the chopper-stabilizer circuit includes a chopper switch that oscillates between a first state and a second state, with an amount of time between each oscillation; anda clock signal generator circuit on said chip, wherein the clock signal generator circuit includes a first component that generates white noise voltages, the clock signal generator circuit outputs a first voltage signal derived from the white noise voltages, and the clock signal generator does not create digital noise on a power supply for said clock signal generator;wherein the first voltage signal is provided directly or indirectly to the chopper stabilizer circuit, and the amount of time between oscillations of the chopper switch varies randomly within a selected range based at least in part on the first voltage signal;wherein said clock signal generator circuit includes a symmetrical noise generator circuit and a symmetrical oscillator circuit; andwherein the noise generator circuit includes at least one differential amplifier that amplifies said white noise voltages, a bandpass filter that filters said amplified white noise voltages, and an integrator circuit in a feedback connection with said at least one differential amplifier.