Low voltage input current mirror circuit and method
AssigneeBroadcom Corporation
InventorLawrence M. Burns
Life of this patent
Estimating the term…
Abstract
A low voltage current mirror circuit (also referred to as a bias circuit) for establishing a plurality of bias voltages from an input current supplied to an input terminal of the circuit includes an input stage, a current stage connected to the input stage, a feedback stage connected to the current stage, a reference bias stage connected to the feedback stage and the current stage. The circuit establishes first and second bias voltages suitable for biasing current sources of a first type, and third and fourth bias voltages suitable for biasing current sources of a second type complementary to the first type. The bias voltages track the input current over variations in at least one of process, temperature and power supply voltage.
Claims14
A circuit adapted to be responsive to an input current supplied to an input terminal of the circuit, comprising:
- an input stage adapted to establish a first bias voltage at the input terminal in response to the input current;
- a current stage adapted to produce at least one mirror current proportional to the input current in response to the first bias voltage and a second bias voltage;
- a feedback stage adapted to produce a feedback current proportional to the input current in response to the at least one mirror current;
- and
- a reference bias stage adapted to establish the second bias voltage in response to the feedback current from the feedback stage, whereby the first and second bias voltages track the input current.
A bias circuit for establishing bias voltages from an input current supplied to an input terminal of the bias circuit, comprising:
- input stage means for establishing a first bias voltage at the input terminal in response to the input current;
- current stage means for producing a bias current and a main mirror current each proportional to the input current in response to the first bias voltage and a second bias voltage;
- feedback stage means for producing a feedback current proportional to the input current in response to the bias current and the main mirror current;
- and
- reference bias stage means for establishing the second bias voltage in response to the feedback current, whereby the first and second bias voltages track the input current.
A method of establishing bias voltages suitable for biasing current sources from an input current supplied to a bias circuit, comprising:
- (a) receiving the input current;
- (b) establishing a first bias voltage in response to the input current;
- (c) producing at least one mirror current proportional to the input current in response to the first bias voltage and a second bias voltage;
- (d) producing a feedback current proportional to the input current in response to the at least one mirror current;
- and
- (e) establishing the second bias voltage in response to the feedback current of step (d), whereby the first and second bias voltages track the input current.
Dependencies are inferred from the claim text.