Cirrus Logic Inc.

Vaibhav Pandey

Anindya Bhattacharya

Bhoodev Kumar

Christopher M Dougherty

Ying Ou

A selectable output current mirror may include a reference leg configured to generate a reference current, an output leg electrically coupled to the reference leg in a manner such that the output leg is configured to generate at an output of the output leg an output current proportional to the reference current, wherein the output leg comprises an output leg transistor, a drain path switch coupled between a first non-gate terminal of the output leg transistor and the output of the output leg, and a series combination of a degeneration resistor and a degeneration path switch coupled between a second non-gate terminal of the output leg transistor and a voltage source to the selectable output current mirror. The selectable output current mirror may also include switch control circuitry configured to selectively enable and disable the output leg from generating the output current by selectively enabling and disabling the drain path switch and the degeneration path switch and glitch mitigation circuitry coupled to the second non-gate terminal of the output leg transistor and configured to maintain the second non-gate terminal of the output leg transistor at a substantially-constant voltage during transitions between disabling of the degeneration path switch and enabling of the degeneration path switch.

Glitch mitigation in selectable output current mirrors with degeneration resistors

An amplifier includes input transconductors that receive an input signal, the input signal having a voltage swing. A supply side current mirror generates a gate voltage as a function of input signal voltage and current sources that provide a bias current of the input transconductors as a function of the gate voltage to maintain a constant bias current across the voltage swing of the input signal. Resistors average source voltages of the transconductance-cancelling transconductors to provide an average source voltage and apply the average source voltage to wells of input devices of the transconductance-cancelling transconductors to reduce back bias effect. The input devices are laid out in a same well and have a common centroid to cancel out process mismatches. A first I-DAC trims an offset of first transconductors, and a second I-DAC trims an offset of second transconductors to attain low offsets across a rail-to-rail input common mode range.

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Austin, TX, United States of America

Vaibhav Pandey