Voltage regulator
AssigneeSeiko Instruments Inc.
InventorsAkihito Yahagi, Yotaro Nihei
Life of this patent
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Abstract
Provided is a voltage regulator including an overcurrent protection circuit using a simple circuit. The voltage regulator includes the overcurrent protection circuit including: a first sense transistor having a gate connected to an output terminal of an error amplifier circuit and a drain connected to a sense resistor; a second sense transistor having a gate connected to the output terminal of the error amplifier circuit; and a control transistor having a gate connected to an output terminal of a control circuit, a source connected to a drain of the second sense transistor, and a drain connected to the sense resistor, in which the control transistor is turned on in response to a detection signal output by the control circuit until a reference voltage exceeds a predetermined voltage.
Claims4
A voltage regulator, comprising:
- an output transistor for outputting a current depending on a control voltage to an output terminal;
- an error amplifier circuit for comparing a reference voltage output from a reference voltage circuit and a divided voltage obtained by dividing an output voltage of the output terminal by a resistor to output the control voltage to the output transistor;
- an overcurrent protection circuit for outputting a control signal to the output transistor when an output current output by the output transistor reaches a predetermined current limit value;
- and
- a control circuit for outputting a detection signal to the overcurrent protection circuit until the reference voltage exceeds a predetermined voltage,
- wherein the overcurrent protection circuit comprises:
- a first sense transistor having a gate connected to an output terminal of the error amplifier circuit and a drain connected to a sense resistor;
- a second sense transistor having a gate connected to the output terminal of the error amplifier circuit;
- and
- a control transistor having a gate connected to an output terminal of the control circuit, a source connected to a drain of the second sense transistor, and a drain connected to the sense resistor, and
- wherein the control transistor is turned on in response to the detection signal output by the control circuit.
Dependencies are inferred from the claim text.