Resistor ladder-based multi-reference voltage generator with headroom increasing circuitry
AssigneeQUALCOMM Incorporated
InventorsJiannan Huang, Behnam Sedighi, Dinesh Jagannath Alladi
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Abstract
A multi-reference voltage generator, comprising: a current source; a set of resistors coupled in series with the current source between an upper voltage rail and a lower voltage rail; a first set of switching devices coupled between a first output and a set of taps at respective terminals of the set of resistors, wherein the set of taps includes a first tap and a second tap; a second set of switching devices coupled between a second output and the set of taps, respectively; a switching device coupled between the first tap and the second tap; and a control circuit including an output coupled to a control input of the switching device.
Claims20
A multi-reference voltage generator, comprising:
- a current source;
- a set of resistors coupled in series with the current source between an upper voltage rail and a lower voltage rail;
- a first set of switching devices coupled between a first output and a set of taps at respective terminals of the set of resistors, wherein the set of taps includes a first tap and a second tap;
- a second set of switching devices coupled between a second output and the set of taps, respectively;
- a switching device coupled between the first tap and the second tap;
- and
- a control circuit including an output coupled to a control input of the switching device.
A method of generating first and second reference voltages, comprising:
- generating a current through a set of resistors to generate a set of voltages at a set of taps coupled to the set of resistors, respectively;
- outputting one of the set of voltages at a first selected tap as the first reference voltage;
- outputting the one or another of the set of voltages at a second selected tap as the second reference voltage;
- and
- coupling a first tap to a second tap of the set of taps based on the first selected tap.
Dependencies are inferred from the claim text.