Biasing scheme for low supply headroom applications
AssigneeBroadcom Corporation
InventorsArya R. Behzad, Frank W. Singor
Life of this patent
Estimating the term…
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.
Claims20
A current mirror circuit, comprising:
- a reference portion to provide a reference current, the reference portion including a first transistor, a second transistor, and a first resistor coupled between a gate of the first transistor and a drain of the second transistor;
- and
- a load portion to provide a load current that is proportional to the reference current, the load portion including a third transistor having a gate that is coupled to the gate of the first transistor;
- wherein a drain of the third transistor is coupled to a load circuit;
- and
- wherein a resistance of the first resistor is based on a voltage of the load circuit.
A current mirror circuit, comprising:
- a reference portion to provide a reference current, the reference portion including a first transistor, a second transistor, and means for improving proportionality between the reference current and a load current that is proportional to the reference current, the means for improving coupled between a gate of the first transistor and a drain of the second transistor;
- and
- a load portion to provide the load current, the load portion including a third transistor having a gate that is coupled to the gate of the first transistor;
- wherein a drain of the third transistor is coupled to a load circuit;
- and
- wherein a voltage across the means for improving is based on a voltage of the load circuit.
A current mirror circuit, comprising:
- a reference portion to provide a reference current, the reference portion including a first transistor, a second transistor, and means for improving a relationship between a drain-to-source voltage of the first transistor and a drain-to-source voltage of a third transistor, the means for improving coupled between a gate of the first transistor and a drain of the second transistor;
- and
- a load portion to provide a load current that is proportional to the reference current, the load portion including the third transistor, the third transistor having a gate that is coupled to the gate of the first transistor;
- wherein a drain of the third transistor is coupled to a load circuit;
- and
- wherein a voltage across the means for improving is based on a voltage of the load circuit.
Dependencies are inferred from the claim text.