Analog Devices, Inc.
Current mirror arrangements with adjustable offset buffers

Abstract:

An example current mirror arrangement includes a current mirror circuit, configured to receive an input current signal at an input transistor Q1 and output a mirrored signal at an output transistor Q2. The arrangement further includes a buffer amplifier circuit, having an input coupled to Q1 and an output coupled to Q2. The offset of the buffer amplifier circuit can be adjusted by including circuitry for an input or an output side offset adjustment or by implementing the buffer amplifier circuit as a diamond stage with individually controlled current sources for each of the transistors of the diamond stage. Providing an adjustable offset buffer in a current mirror arrangement may advantageously allow benefiting from the use of a buffer outside of a feedback loop of a current mirror, while being able to reduce the buffer offset due to mismatch between master and slave sides of the current mirror circuit.