Methods and systems for a MOSFET-bipolar complimentary symmetry driver with local feedback for bias stabilization
AssigneeBroadcom Corporation
InventorSteven L. Caine
Life of this patent
Estimating the term…
Abstract
A SLIC assembly includes high voltage operational amplifiers (op amps) and low voltage op amps. The high voltage op amps are used to drive ring and tip signals while the low voltage op amps are used to drive other signals. The low voltage op amps include Class A-B amplifier drivers based on bipolar transistors. Bipolar transistors are also provided as bias compensating diodes for bias point stabilization over dynamic operating conditions such as temperature. The high voltage op amps include a composite MOSFET-bipolar complimentary symmetry driver stage that offers the bias control and stability of a bipolar device topology and drive capabilities of a power MOSFET device.
Claims10
A MOSFET-bipolar driver, comprising:
- a MOSFET output driver;
- at least one first bipolar transistor coupled to the MOSFET output driver;
- a feedback path coupled between said first bipolar transistor and an output of said MOSFET;
- and
- a diode-connected second bipolar transistor coupled to a base of said first bipolar transistor, said diode-connected second bipolar transistor biasing said first bipolar transistor;
- wherein said first bipolar transistor biases said MOSFET to output a current, said feedback path provides an indication of said current from said MOSFET to said first bipolar transistor, and said first bipolar transistor adjusts said bias in response to said indication.
A MOSFET-Bipolar driver with local feedback for bias stabilization, comprising:
- an input terminal;
- an output terminal;
- a feedback resistance coupled between said output terminal and a first node;
- a MOSFET current source coupled between said first node and said input terminal;
- at least one bipolar transistor coupled between said input terminal and said MOSFET current source, and coupled to said feedback resistance;
- and
- at least one diode coupled to said input terminal;
- whereby said at least one diode and said at least one bipolar transistor bias said MOSFET to provide a current to said output terminal through said feedback resistance, thereby generating a feedback voltage across said feedback resistance;
- whereby said at least one bipolar transistor adjusts said bias to said MOSFET in response to said feedback voltage.
A MOSFET-Bipolar complimentary symmetry driver with local feedback for bias stabilization, comprising:
- first and second input terminals;
- at least one diode coupled between said first and second input terminals;
- an output terminal;
- a first feedback resistance coupled to said output terminal;
- a first MOSFET current source coupled to said first feedback resistance;
- a first set of one or more bipolar transistors coupled between said first input terminal and said first MOSFET;
- a second feedback resistance coupled to said output terminal;
- a second MOSFET current source coupled to said second feedback resistance;
- a second set of one or more bipolar transistors coupled between said second input terminal and said second MOSFET;
- whereby said at least one diode and said first and second sets of at least one bipolar transistor bias said first and second MOSFET current sources in response to first and second signals provided to said first and second input terminals, respectively, to provide current to said output terminal through said first and second feedback resistance, thereby generating first and second feedback voltages across said first and second feedback resistances;
- whereby said first and second sets of at least one bipolar transistor adjust said bias to said first and second MOSFET current sources, respectively, in response to said feedback voltages.
Dependencies are inferred from the claim text.