Biasing scheme for low supply headroom applications
AssigneeBroadcom Corporation
InventorsArya Reza Behzad, Frank Wayne Singor
Life of this patent
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Abstract
Methods and apparatus for improving the current matching within current mirror circuits in applications such as low voltage integrated circuits. Embodiments of the present invention attempt to maintain the proper current ratio between reference and output supplies by adjusting the reference output of the current mirror. An existing reference voltage on the output side of the mirror can be used or a reference voltage can be created to be used for the voltage regulation of the reference side of the current mirror.
Claims17
A current mirror circuit, comprising:
- a reference current side capable of generating a reference current, the reference current side including first and second transistors coupled to a third transistor, wherein gates of the first and second transistors receive a differential signal;
- and
- a load current side capable of generating a load current that is proportional to the reference current, the load current side including fourth and fifth transistors coupled to a sixth transistor, wherein gates of the fourth and fifth transistors receive a differential signal, and wherein a gate of the third transistor is coupled to a gate of the sixth transistor.
A method of maintaining a current ratio in a current mirror circuit, the current mirror circuit including a reference current side having first and second transistors coupled to a third transistor, and a load current side having fourth and fifth transistors coupled to a sixth transistor, the sixth transistor having a gate that is coupled to a gate of the third transistor, the method comprising:
- receiving a differential signal at gates of the first and second transistors;
- receiving a differential signal at gates of the fourth and fifth transistors;
- generating a reference current in the reference current side;
- and
- generating a load current in the load current side that is proportional to the reference current generated in the reference current side.
Dependencies are inferred from the claim text.