Voltage regulator
A voltage regulator includes an error amplifier which receives a feedback voltage and a reference voltage and thereby controls a gate voltage of an output transistor, a non-regulation detection circuit having a differential amplifier circuit operating on a current corresponding to an output current of the output transistor, and an overshoot suppression circuit having an overshoot detection circuit which enables an overshoot detection by a signal indicating the detection of non-regulation state from the non-regulation detection circuit.
1. A voltage regulator having an overshoot suppression function of an output voltage, comprising:
a feedback circuit configured to provide a feedback voltage based on an output voltage provided from an output transistor;
an error amplifier configured to receive the feedback voltage and a reference voltage and thereby control a gate voltage of the output transistor in such a manner that the output voltage coincides with a prescribed output voltage;
a non-regulation detection circuit having a differential amplifier circuit operating on a current corresponding to an output current of the output transistor and an output inverter connected to an output terminal of the differential amplifier circuit, and configured to detect a non-regulation state of the voltage regulator based on the gate voltage of the output transistor being in a state where a source voltage of the output transistor is lower than the prescribed output voltage; and
an overshoot suppression circuit having an overshoot detection circuit configured to enable an overshoot detection of the output voltage by a signal indicating the detection of the non-regulation state from the non-regulation detection circuit.
2. The voltage regulator according to claim 1 ,
wherein the non-regulation detection circuit comprises a sense transistor whose gate is connected to a gate of the output transistor, and
wherein the sense transistor provides an operating current of the differential amplifier circuit.
3. The voltage regulator according to claim 1 ,
wherein the non-regulation detection circuit has a second constant current source connected to the output terminal of the differential amplifier circuit.
4. The voltage regulator according to claim 1 ,
wherein the non-regulation detection circuit has a reference voltage circuit operating on a current corresponding to the output current of the output transistor.
5. The voltage regulator according to claim 2 ,
wherein the non-regulation detection circuit has a first constant current source in series with the sense transistor.
6. The voltage regulator according to claim 2 ,
wherein the non-regulation detection circuit has a second constant current source connected to the output terminal of the differential amplifier circuit.
7. The voltage regulator according to claim 2 ,
wherein the non-regulation detection circuit has a reference voltage circuit operating on a current corresponding to the output current of the output transistor.
8. The voltage regulator according to claim 3 ,
wherein the non-regulation detection circuit has a reference voltage circuit operating on a current corresponding to the output current of the output transistor.
9. The voltage regulator according to claim 5 ,
wherein the non-regulation detection circuit has a second constant current source connected to the output terminal of the differential amplifier circuit.
10. The voltage regulator according to claim 5 ,
wherein the non-regulation detection circuit has a reference voltage circuit operating on a current corresponding to the output current of the output transistor.
11. The voltage regulator according to claim 6 ,
wherein the non-regulation detection circuit has a reference voltage circuit operating on a current corresponding to the output current of the output transistor.