Linear regulator with low overshooting in transient state
AssigneeSTMicroelectronics S.r.l.
InventorNicolas Marty
Life of this patent
Estimating the term…
Abstract
A voltage regulator includes a regulation MOS transistor with low serial resistance having a first terminal connected to a voltage source and a second terminal connected to the output of the voltage regulator and an amplifier having an output driving a gate of the transistor. The gate is driven based upon a difference between a reference voltage and a feedback voltage. The regulator may also include an anti-overshoot switch with a first terminal connected to the gate of the regulation MOS transistor and a second terminal is taken to a potential for turning the regulation MOS transistor off. A switch controller closes the switch when the output voltage of the regulator is higher than a first threshold. The first threshold may be higher than the nominal value of the output voltage.
Claims24
A voltage regulator comprising:
- a regulation MOS transistor having a first conduction terminal receiving a supply voltage, a second conduction terminal providing an output voltage of the voltage regulator, and a gate, said regulation MOS transistor having a low serial resistance;
- an amplifier for driving the gate of said regulation MOS transistor based upon a difference between a reference voltage and a feedback voltage;
- a switch having a first terminal connected to the gate of said regulation MOS transistor and a second terminal connected to a potential for turning said regulation MOS transistor off;
- and
- a switch controller for monitoring the output voltage and closing said switch when the output voltage is higher than a first threshold, the first threshold being higher than a nominal value of the output voltage.
A voltage regulator comprising:
- a regulation transistor having a first conduction terminal receiving a supply voltage, a second conduction terminal providing an output voltage of the voltage regulator, and a control terminal;
- an amplifier for driving the control terminal of said regulation transistor based upon a difference between a reference voltage and a feedback voltage;
- a switch having a first terminal connected to the control terminal of said regulation transistor and a second terminal for turning said regulation transistor off;
- and
- a switch controller for monitoring the output voltage and closing said switch when the output voltage is higher than a first threshold, the first threshold being higher than a nominal value of the output voltage.
A mobile telephone comprising:
- at least one circuit for transmitting and receiving communications signals;
- a battery for supplying power to said at least one circuit;
- and
- a voltage regulator for regulating the power supplied by said battery to said at least one circuit, said voltage regulator comprising
- a regulation transistor having a first conduction terminal receiving a supply voltage, a second conduction terminal providing an output voltage of the voltage regulator, and a control terminal,
- an amplifier for driving the control terminal of said regulation transistor based upon a difference between a reference voltage and a feedback voltage,
- a switch having a first terminal connected to the control terminal of said regulation transistor and a second terminal for turning said regulation transistor off, and
- a switch controller for monitoring the output voltage and closing said switch when the output voltage is higher than a first threshold, the first threshold being higher than a nominal value of the output voltage.
A method for limiting overshooting of an output voltage of a voltage regulator receiving a supply voltage when the supply voltage increases rapidly, the voltage regulator comprising a regulation MOS transistor having a high gate capacitance, the method comprising:
- driving a gate of the regulation MOS transistor with a current from an amplifier where the current is independently insufficient to rapidly turn off the regulation transistor;
- connecting a switch between the gate of the regulation transistor and a potential for turning off the regulation transistor;
- and
- closing the switch when the output voltage of the voltage regulator is higher than a first threshold to temporarily assist the amplifier to turn off the regulation transistor, the first threshold being higher than a nominal value of the output voltage.
A method for using a voltage regulator comprising a regulation transistor having a first conduction terminal receiving a supply voltage, a second conduction terminal providing an output voltage of the voltage regulator, and a control terminal, the method comprising:
- driving the control terminal of the regulation transistor based upon a difference between a reference voltage and a feedback voltage;
- connecting a first terminal of a switch to the control terminal of the regulation transistor and a second terminal for turning the regulation transistor off;
- monitoring the output voltage;
- and
- closing the switch when the output voltage is higher than a first threshold, the first threshold being higher than a nominal value of the output voltage.
Dependencies are inferred from the claim text.