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US 6,646,495 B2Granted
Threshold voltage adjustment scheme for increased output swing
AssigneeTexas Instruments Incorporated
InventorRaul A. Perez
Life of this patent
Estimating the term…
Abstract
The present invention provides increased output swing by connecting a buffer backgate to an upper rail potential (125) during the no load current condition. This can be done through the use of a comparator (440) and a multiplexer (460), thereby changing the threshold voltage of the buffer (115).
Claims20
A voltage regulator circuit, comprising:
- an input amplifier;
- a source follower coupled to an output of said input amplifier;
- a pass device coupled to an output of said source follower, said pass device also coupled to a node where voltage is to be regulated;
- a compensating capacitor coupled between said node and a first power supply node;
- a comparator having a first input coupled to the output of said source follower and a second input coupled to a reference voltage node;
- and
- a multiplexer having a first input coupled to the output of said source follower, a second input coupled to a second power supply node and an output coupled to a backgate of said source follower.
4 more elements
A voltage regulator circuit, comprising:
- a supply voltage node;
- an output voltage node;
- a ground node;
- an input amplifier having an input and an output;
- an NMOS transistor buffer having a source, a backgate, a drain connected to the supply voltage node, and a gate connected to the output of the input amplifier;
- a PMOS transistor pass device having a source connected to the supply voltage node, a backgate connected to the supply voltage node, a gate connected to the source of the NMOS transistor buffer, and a drain connected to the output voltage node;
- a compensating capacitor connected between the output voltage node and the ground node;
- a comparator having a first input connected to the source of the NMOS transistor buffer, a second input connected to a reference voltage node, and an output;
- and
- a multiplexer having a first input connected to the source of the NMOS transistor buffer, a second input connected to the supply voltage node, a select input connected to the output of the comparator, and an output connected to the backgate of the NMOS transistor buffer.
7 more elements
An electronic circuit, comprising:
- an input stage;
- a source follower stage having an input coupled to said input stage, said source follower stage also having an output;
- a pass device stage having an input coupled to the output of said source follower stage, and an output coupled to a node where voltage is to be regulated;
- and
- a multiplexer having a first input for receiving a control signal indicative of a condition at said node, said multiplexer having a second input coupled to a supply voltage, a third input coupled to the output of said source follower stage, and an output coupled to a backgate of said source follower stage.
2 more elements
A method for regulating a voltage output, the method comprising:
- providing a current flow capability through a voltage regulator circuit to drive a load, said voltage regulator circuit comprising a source follower stage serially connected to a gate of a pass device stage, the pass device stage controlling the voltage to the load;
- and
- responsive to conditions at the load, selectively connecting a supply voltage to a backgate input of said source follower stage to drive said pass device stage to control current to the load.
Dependencies are inferred from the claim text.