Voltage clamp
AssigneeQUALCOMM Incorporated
InventorWilliam F. Ellersick
Life of this patent
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Abstract
An active over-voltage clamp system includes at least one over-voltage detector that is responsive to an input voltage and provides a first current. The system also includes a replica over-voltage circuit that provides a second current, and circuitry subtracting the second current from the first current to produce a difference current. The system further includes a differential clamp activated in response to the difference current. The differential clamp prevents the input voltage from increasing beyond a target voltage.
Claims22
An active over-voltage clamp system, said system comprising:
- at least one over-voltage detector that is responsive to an input voltage and provides a first current;
- a replica over-voltage circuit that provides a second current;
- circuitry subtracting the second current from the first current to produce a difference current;
- and
- a differential clamp activated in response to the difference current, wherein the differential clamp prevents the input voltage from increasing beyond a target voltage.
A method for stabilizing an input voltage, the method comprising:
- producing a first current corresponding to an input voltage;
- producing a second current corresponding to a target input voltage;
- producing a third current by subtracting the second current from the first current;
- inputting the third current to a differential clamp, the differential clamp stabilizing the input voltage by applying a fourth current to nodes receiving the input voltage.
A system for driving signals, the system comprising:
- an amplifier circuit;
- one or more thin-oxide devices configured to receive output from the amplifier circuit and to use the amplifier output to drive said signals;
- circuitry producing a first current, the first current associated with a voltage of the amplifier output;
- circuitry producing a second current, the second current associated with a target operating voltage of the one or more thin-oxide devices;
- and
- a voltage clamp receiving a third current that comprises a difference between the first and second currents, the voltage clamp creating a fourth current from the third current and applying the fourth current to one or more nodes of the amplifier circuit to decrease the output voltage of the amplifier circuit.
A system for protecting a device from an amplifier output voltage, the system comprising:
- means for generating a first current that is indicative of the amplifier output voltage;
- means for generating a second current that is indicative of a target voltage for the device;
- means for subtracting the second current from the first current to produce a third current;
- and
- means for receiving the third current and clamping the amplifier output voltage based at least in part on the third current.
Dependencies are inferred from the claim text.