Voltage regulator including a linear transconductance amplifier
First Claim
1. A voltage regulator comprising a FET having a source coupled to an input terminal for a voltage to be regulated, a drain coupled to an output terminal for a regulated output voltage, and a gate, a linear transconductance amplifier responsive to the output voltage for supplying a current drive to the gate of the FET, a current-sensing resistor in series with the source-drain path of the FET between the input and output terminals, and a current limiting circuit responsive to an excessive current flow through the current-sensing resistor for reducing current drive from the transconductance amplifier to the gate of the FET.
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Accused Products
Abstract
A voltage regulator for an electronic circuit card includes a FET with a source supplied via an input LC filter with a voltage to be regulated, a drain for delivering a regulated output voltage via a current-sensing resistor and an output LC circuit, and a gate which is supplied with a current drive from a linear transconductance amplifier having a differential input responsive to the regulated output voltage relative to a reference voltage. The regulator provides large bandwidth low voltage drop regulation without requiring higher voltage supply for the gate of the FET. A current limiting circuit reduces the current drive in response to excessive current through the current-sensing resistor, and a turn-on control circuit reduces the current drive to provide a controlled turn-on for hot insertion of the card into electronic equipment.
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Citations
13 Claims
- 1. A voltage regulator comprising a FET having a source coupled to an input terminal for a voltage to be regulated, a drain coupled to an output terminal for a regulated output voltage, and a gate, a linear transconductance amplifier responsive to the output voltage for supplying a current drive to the gate of the FET, a current-sensing resistor in series with the source-drain path of the FET between the input and output terminals, and a current limiting circuit responsive to an excessive current flow through the current-sensing resistor for reducing current drive from the transconductance amplifier to the gate of the FET.
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6. A voltage regulator comprising:
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an input terminal for receiving an input voltage to be regulated; an output terminal for delivering a regulated output voltage; a current-sensing resistor; a FET having a source coupled to the input terminal, a drain coupled via the current-sensing resistor to the output terminal, and a gate; a linear transconductance amplifier having differential input terminals responsive to the output voltage and a reference voltage and an output coupled to the gate of the FET for supplying current thereto; and a current limiting circuit responsive to an excessive current flow through the current-sensing resistor for reducing current drive from the linear transconductance amplifier to the gate of the FET. - View Dependent Claims (7, 8, 9, 10, 11)
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12. An electronic circuit card including two voltage regulators arranged to supply respectively positive and negative regulated voltages to electronic circuits on the circuit card, each voltage regulator comprising a FET having a source coupled to an input terminal for a voltage to be regulated, a drain coupled to an output terminal for a regulated output voltage, and a gate, a linear transconductance amplifier responsive to the output voltage for supplying a current drive to the gate of the FET, a current-sensing resistor in series with the source-drain path of the FET between the input and output terminals, and a current limiting circuit responsive to an excessive current flow through the current-sensing resistor for reducing current drive from the transconductance amplifier to the gate of the FET.
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13. An electronic circuit card including two voltage regulators arranged to supply respectively positive and negative regulated voltages to electronic circuits on the circuit card, each voltage regulator comprising:
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an input terminal for receiving an input voltage to be regulated; an output terminal for delivering a regulated output voltage; a current-sensing resistor; a FET having a source coupled to the input terminal, a drain coupled via the current-sensing resistor to the output terminal, and a gate; a linear transconductance amplifier having differential input terminals responsive to the output voltage and a reference voltage and an output coupled to the gate of the FET for supplying current thereto; and a current limiting circuit responsive to an excessive current flow through the current-sensing resistor for reducing current drive from the linear transconductance amplifier to the gate of the FET.
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Specification