A circuit includes a reference voltage generator circuit and a regulation loop circuit having an output voltage terminal. The regulator circuit further includes a fault detection circuit having a first input terminal coupled to the output voltage regulator terminal of the regulation loop circuit. The fault detection circuit asserts, on an output terminal of the fault detection circuit, a fault flag signal responsive to a voltage on the first input terminal falling below a first threshold. A programmable filter is coupled between the reference voltage generator circuit and the regulation loop circuit and is coupled to the fault detection circuit. The programmable filter has a programmable time constant. The programmable filter responds to an assertion of the fault flag signal by decreasing the time constant.

A circuit includes a reference voltage generator circuit and a regulation loop circuit having an output voltage terminal. The regulator circuit further includes a fault detection circuit having a first input terminal coupled to the output voltage regulator terminal of the regulation loop circuit. The fault detection circuit asserts, on an output terminal of the fault detection circuit, a fault flag signal responsive to a voltage on the first input terminal falling below a first threshold. A programmable filter is coupled between the reference voltage generator circuit and the regulation loop circuit and is coupled to the fault detection circuit. The programmable filter has a programmable time constant. The programmable filter responds to an assertion of the fault flag signal by decreasing the time constant.

An electronic device (10) includes: a power supply (11); a first switch (12) that is connected at least to one pole of the power supply (11) and interrupts power supplied from the power supply (11) to a load (13); a second switch (14) that is positioned on a load (13) side with reference to the first switch (12) and interrupts power supplied from the power supply (11) to the load (13); a first power line (L11) that is connected to one end portion of an electric contact of the second switch (14), the one end portion being located on a first-switch (12) side; a second power line (L12) that is connected to another end portion of the electric contact of the second switch (14); a third power line (L13) that is connected to another pole of the power supply (11); and an electric element (resistor 15) that is connected between the first and second power lines (L11, L12) in parallel to the electric contact or connected between the first and third power lines (L11, L13), such that the electric contact of the second switch (14) is not charged when the first and second switches (12, 14) interrupt power.

A power control device includes: an output voltage controller configured to control an output voltage based on a feedback voltage corresponding to the output voltage; and an overvoltage protector configured to continue or stop the operation of the output voltage controller based on a first detection result of whether the output voltage has exceeded an output voltage threshold value and a second detection result of whether the feedback voltage has fallen to or below a feedback voltage threshold value.

Disclosed are a series regulator and electronic equipment. The series regulator includes a first amplifier that drives a first transistor connected between a power supply and a load, a second amplifier that drives a second transistor connected in parallel to the first transistor, an amplifier control circuit that controls whether or not operation of the first amplifier is possible according to the load, and a first overcurrent protection circuit that limits a first output current flowing in the first transistor to a first overcurrent set value or smaller. The first overcurrent protection circuit carries out variable control of the first overcurrent set value according to a second output current flowing in the second transistor. The electronic equipment includes the series regulator and a load that receives power supply from the series regulator and operates.

A fast response amplifier circuit includes a pre-stage circuit and an output stage circuit. The pre-stage circuit generates a control signal according to a difference between a first input signal and a second input signal. The output stage circuit generates an output signal at an output node according to the control signal. The output stage circuit includes: a power transistor controlled by a driving signal to generate the output signal; a voltage positioning transistor operates according to the output signal to steer a first portion and a second portion of a bias current; an overshoot detecting circuit detecting an overshoot of the output signal to generate an overshoot indicating signal; and a first overshoot suppressor which generates a first overshoot suppressing signal according to the overshoot indicating signal to adjust a conduction resistance of the power transistor to suppress an overshoot of the output signal.

A fast response amplifier circuit includes a pre-stage circuit and an output stage circuit. The pre-stage circuit generates a control signal according to a difference between a first input signal and a second input signal. The output stage circuit generates an output signal at an output node according to the control signal. The output stage circuit includes: a power transistor controlled by a driving signal to generate the output signal; a voltage positioning transistor operates according to the output signal to steer a first portion and a second portion of a bias current; an overshoot detecting circuit detecting an overshoot of the output signal to generate an overshoot indicating signal; and a first overshoot suppressor which generates a first overshoot suppressing signal according to the overshoot indicating signal to adjust a conduction resistance of the power transistor to suppress an overshoot of the output signal.

A voltage regulator includes an operational amplifier that compares a feedback voltage that is proportional to an output voltage and a predetermined reference voltage that corresponds to a desired output voltage. The operational amplifier controls the conduction state of an output transistor according to the comparison. A detecting circuit monitors the operating state of the operational amplifier, and in the case that the operational amplifier is not operating, outputs a signal which causes the output transistor to be placed in a non-conductive state.

A voltage regulator includes an operational amplifier that compares a feedback voltage that is proportional to an output voltage and a predetermined reference voltage that corresponds to a desired output voltage. The operational amplifier controls the conduction state of an output transistor according to the comparison. A detecting circuit monitors the operating state of the operational amplifier, and in the case that the operational amplifier is not operating, outputs a signal which causes the output transistor to be placed in a non-conductive state.

A power control device includes: an output voltage controller configured to control an output voltage based on a feedback voltage corresponding to the output voltage; and an overvoltage protector configured to continue or stop the operation of the output voltage controller based on a first detection result of whether the output voltage has exceeded an output voltage threshold value and a second detection result of whether the feedback voltage has fallen to or below a feedback voltage threshold value.