CMOS voltage regulator with diode-connected transistor divider circuit
AssigneeInformation Storage Devices, Inc.
InventorHieu Van Tran
Life of this patent
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Abstract
The voltage regulator of the present invention is configured in a negative feedback operational amplifier loop with diode connected p-MOS devices serving as a resistor divider to reduce the current loading to the voltage multiplier. Each diode connected p-MOS has its own well tied to its source so the VGS (gate to source voltage) of each p-MOS is precisely mirrored across the diode chain by the negative feedback action. This gives a precise voltage at the output of the regulator referenced to a reference voltage VREF. The regulator uses very little current without requiring large value resistors by utilizing the diode connected p-MOS transistors as a resistor divider.
Claims9
A voltage regulator for receiving a voltage input and providing a regulated voltage output comprising:
- a differential amplifier having an amplifier output, a first input coupled to a feedback voltage from said regulated voltage output, and a second input coupled to a reference voltage;
- a plurality of transistors connected in series, a first of the series of transistors being diode coupled when active, said first transistor providing said feedback voltage that is substantially equal to a predetermined portion of said regulated voltage output when the first transistor is active, the rest of the series of transistors being diode coupled, the series of transistors having a first end thereof coupled to a circuit ground and a second end thereof coupled to the regulated voltage output;
- and
- a regulating transistor coupled between the voltage input and the first end of the series of diode connected transistors and controlled by the amplifier output to provide a current through the series of diode connected transistors to maintain the voltage between the inputs of the differential amplifier substantially zero, said regulating transistor keeping said regulated voltage output at approximately a predetermined multiple of said reference voltage.
Dependencies are inferred from the claim text.