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US 2009/0212753 A1Published application
Voltage regulator having fast response to abrupt load transients
AssigneeMediatek Inc.
InventorChih-Hong Lou
Life of this patent
Estimating the term…
Abstract
A voltage regulator includes an undervoltage detector having a charge transistor smaller than an output transistor of the voltage regulator, providing a detection path for fast response, compensating undervoltage without large control current when loading changes from light to heavy.
Claims19
A voltage regulator, comprising:
- an amplifier having a first input coupled to a first reference voltage, a second input coupled to a feedback signal, and an output producing a control signal;
- an output transistor having a control input, a first electrode coupled to a first input voltage, and a second electrode coupled to output a regulated output voltage to an output terminal of the voltage regulator;
- a feedback circuit coupled to the output terminal of the voltage regulator to produce the feedback signal;
- an undervoltage detector coupled to the first reference voltage and the feedback signal, producing a charge control signal indicating occurrence of an output undervoltage of at least a first predetermined magnitude;
- and
- a charge transistor coupled between a second input voltage and the output terminal, having a control input responsive to the charge control signal to charge the output undervoltage.
3 more elements
A voltage regulator, comprising:
- an amplifier having a first input coupled to a first reference voltage, a second input coupled to a feedback signal, and an output producing a control signal;
- an output transistor having a control input, a first electrode coupled to a first input voltage, and a second electrode coupled to output a regulated output voltage to an output terminal of the voltage regulator;
- a feedback circuit coupled to the output terminal of the voltage regulator to produce the feedback signal;
- and
- an overvoltage detector comprising:
- a low-pass filter coupled to the output terminal of the voltage regulator and producing a filtered signal;
- an overvoltage comparator having a first input coupled to the output terminal of the voltage regulator and a second input coupled to the filtered signal, producing a discharge control signal indicating occurrence of an output overvoltage of at least a predetermined magnitude;
- and
- a discharge transistor having a first electrode coupled to the output terminal, a second electrode coupled to a second reference voltage, and a control input responsive to the discharge control signal to discharge the output overvoltage.
6 more elements
A voltage regulator, comprising:
- an amplifier having a first input coupled to a first reference voltage, a second input, and an output;
- an inverter having an input coupled to the output of the amplifier, and an output;
- an output transistor having a control input coupled to the output of the inverter, a first electrode coupled to a first input voltage, and a second electrode coupled to an output terminal of the voltage regulator;
- a feedback circuit having an input coupled to the output terminal of the voltage regulator and an output coupled to the second input of the amplifier;
- an undervoltage comparator having a first input coupled to the first reference voltage, a second input coupled to the output of the feedback circuit, and an output;
- a control transistor having a first electrode, a second electrode coupled to a second reference voltage, and a control input connected to the output of the undervoltage comparator;
- a charge transistor having a first electrode coupled to a second input voltage, a second electrode coupled to the output terminal of the voltage regulator, and a control input coupled to the first electrode of the control transistor;
- and
- a blocking device coupled between the control inputs of the output transistor and the charge transistor.
6 more elements
Dependencies are inferred from the claim text.