Protection circuit for extending headroom with off-chip inductors
AssigneeBroadcom Corporation
InventorsLawrence M. Burns, Leonard Dauphinee
Life of this patent
Estimating the term…
Abstract
A protection circuit for extending the dynamic range of an amplifier circuit is described. Off-chip impedances, such as inductors, cause the output of the circuit to swing above and below the bias voltage. A protection circuit is included, either on-chip or off-chip, to protect the integrated circuit components if there is a fault condition in either of the off-chip impedances.
Claims48
An electronic circuit assembly, comprising:
- an electronic circuit,
- a first impedance, and
- a second impedance, wherein
- said electronic circuit has a positive output connected to a bias voltage through said first impedance, and a negative output, connected to said bias voltage through said second impedance;
- and
- said positive output further being connected to said bias voltage through a first off-chip impedance and said negative output further being connected to said bias voltage through a second off-chip impedance.
An circuit for amplifying a signal, comprising:
- a substrate,
- a plurality of gain stages, wherein each gain stage of said plurality of gain stages has a positive output and a negative output,
- each said positive output being combined into a combined positive output and each said negative output being combined into a combined negative output,
- said combined positive output being connected to a second port of a common point resistor through a first impedance and said combined negative output being connected to said second port of said common point resistor through a second impedance, wherein a first port of said common point resistor is connected to a first potential,
- said first impedance being a first inductor and a first resistor disposed on said substrate and said second impedance being a second inductor and a second resistor disposed on said substrate,
- said combined positive output further being connected to said bias voltage through a first off-chip impedance and said combined negative output further being connected to said bias voltage through a second off-chip impedance,
- whereby said first off-chip impedance and said second off-chip impedance raises a direct current voltage on said positive output and on said negative output of each said gain stage while having little or no effect on alternating current performance.
A method for extending dynamic range of an output of an amplifier, the amplifier comprising a plurality of gain stages, each of the plurality of gain stages having a positive output and a negative output, wherein the positive outputs are combined to create a combined positive output and the negative outputs are combined to create a combined negative output, and further wherein a first on-chip impedance is connected between the combined positive output and a bias voltage of the amplifier and a second on-chip impedance is connected between the combined negative output and the bias voltage, comprising the steps of:
- (1) connecting a first off-chip impedance between the combined positive output of the gain stages and the bias voltage;
- and
- (2) connecting a second off-chip impedance between the combined negative output of the gain stages and the bias voltage.
A method of protecting an electronic circuit assembly from over-current damage, wherein the electronic circuit assembly is comprised of an electronic circuit having an output, the output being connected through an on-chip impedance to create a circuit assembly output, comprising the steps of:
- (1) disposing a protection impedance between a first potential and a protection impedance port, said protection impedance port being connected to the circuit assembly output of the electronic circuit assembly;
- (2) disposing a capacitor between said protection impedance port and a second potential, wherein said second potential is substantially equal to an alternating current ground;
- and
- (3) connecting the output of the electronic circuit through one or more off-chip impedances to the first potential, said off-chip impedances causing a current through the on-chip impedance to be substantially zero in a normal operating condition.
An electronic circuit assembly, comprising:
- an electronic circuit, and
- an on-chip impedance, wherein
- said electronic circuit has an output connected to a bias voltage through said on-chip impedance, and
- said output further being connected to said bias voltage through an off-chip impedance.
Dependencies are inferred from the claim text.