Voltage clamping circuit
AssigneeSemiconductor Components Industries, LLC
InventorAdam John WHITWORTH
Life of this patent
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Abstract
In a general aspect, a circuit can include a pass device configured to receive an input voltage and provide an output voltage. The circuit can further include a current sink coupled with a control terminal of the pass device, the current sink being configured to discharge the control terminal of the pass device to limit the output voltage in response to the input voltage exceeding a threshold voltage. The circuit can also include a switch coupled in series with the current sink, the switch being configured to enable the current sink in response to the input voltage exceeding the threshold voltage.
Claims20
A circuit comprising:
- a pass device configured to receive an input voltage and provide an output voltage;
- a current sink coupled with a control terminal of the pass device, the current sink being configured to discharge the control terminal of the pass device to limit the output voltage in response to the input voltage exceeding a threshold voltage;
- and
- a switch coupled in series with the current sink, the switch being configured to enable the current sink in response to the input voltage exceeding the threshold voltage.
A circuit comprising:
- a pass device configured to receive an input voltage and provide an output voltage;
- a current sink coupled with a control terminal of the pass device, the current sink being configured to discharge the control terminal of the pass device to limit the output voltage in response to the input voltage exceeding a threshold voltage;
- a switch coupled in series with the current sink, the switch being configured to enable the current sink in response to the input voltage exceeding the threshold voltage;
- a voltage reference circuit coupled with a control terminal of the current sink, the voltage reference circuit being configured to generate a voltage corresponding with the threshold voltage;
- an overvoltage detection circuit coupled to a control terminal of the switch, the overvoltage detection circuit being configured to:
- turn off the switch to disable the current sink in response to the input voltage being less than or equal to the threshold voltage;
- and
- turn on the switch to enable the current sink in response to the input voltage being greater than the threshold voltage;
- and
- a charge pump coupled to the control terminal of the pass device, the charge pump being configured to receive the output voltage and provide a control voltage to the pass device, the control voltage being greater than the output voltage.
A method of operating a circuit, the method comprising:
- receiving an input voltage at a pass device of the circuit;
- providing, with the pass device, an output voltage based on the input voltage;
- determining that the input voltage exceeds a threshold voltage;
- and
- in response to the input voltage exceeding the threshold voltage:
- enabling a current sink coupled with a control terminal of the pass device;
- and
- discharging, with the current sink, the control terminal of the pass device to limit the output voltage.
Dependencies are inferred from the claim text.