A voltage supply circuit for an electronic circuit includes a switch configured to selectively connect a supply input of the electronic circuit with a main supply voltage source. An auxiliary voltage supply unit has an auxiliary voltage output coupled to the supply input of the electronic circuit. The auxiliary voltage supply unit is configured to at least temporarily output an auxiliary voltage to the supply input. The auxiliary voltage has a voltage level lower than a voltage level of a main supply voltage supplied by the main supply voltage source.

A voltage supply circuit for an electronic circuit includes a switch configured to selectively connect a supply input of the electronic circuit with a main supply voltage source. An auxiliary voltage supply unit has an auxiliary voltage output coupled to the supply input of the electronic circuit. The auxiliary voltage supply unit is configured to at least temporarily output an auxiliary voltage to the supply input. The auxiliary voltage has a voltage level lower than a voltage level of a main supply voltage supplied by the main supply voltage source.

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.

Provided is a sensor device wherein malfunction due to a negative surge is suppressed. This sensor device is provided with: a sensor element wherein electrical characteristics change corresponding to physical quantities; a signal processing circuit that processes output signals of the sensor element; a first transistor element that supplies currents to the sensor element and the signal processing circuit; a control circuit that controls a base current of the first transistor element; a power supply terminal; and a ground terminal. The sensor device is characterized in that the control circuit is provided with a limiting section that limits a current flowing from the ground terminal toward a base terminal of the first transistor element.

A regulator includes a driving circuit, an amplifying circuit and an overvoltage protection circuit. The driving circuit is configured to receive an input voltage and provide an output voltage through an output terminal. The amplifying circuit is configured to control the driving circuit according to the output voltage. The overvoltage protection circuit is configured to conduct a first current from the output terminal of the overprotection circuit to a ground terminal. When the overvoltage protection circuit detects that a voltage level of a node coupled to the driving circuit is increased, the overvoltage protection circuit conducts a second current from the output terminal of the overprotection circuit to the ground terminal to lower the output voltage, in which the second current is larger than the first current.

A system may include a switch, a multiple stage voltage converter, and a regulation circuit. The switch may generate a pre-regulation signal based on an input signal. The multiple stage voltage converter may generate an output signal based on the input signal using a clock. The regulation circuit may generate a regulation signal based on the output signal and may generate a clock reference based on at least one of the pre-regulation signal and the regulation signal. The regulation circuit may generate the clock based on at least one of the pre-regulation signal, the regulation signal, and the clock reference and determine whether a voltage level of the regulation signal is within a range. If the voltage level of the regulation signal is within the range, the regulation circuit may generate a switch signal. The switch may adjust a voltage level of the pre-regulation signal based on the switch signal.

A system may include a switch, a multiple stage voltage converter, and a regulation circuit. The switch may generate a pre-regulation signal based on an input signal. The multiple stage voltage converter may generate an output signal based on the input signal using a clock. The regulation circuit may generate a regulation signal based on the output signal and may generate a clock reference based on at least one of the pre-regulation signal and the regulation signal. The regulation circuit may generate the clock based on at least one of the pre-regulation signal, the regulation signal, and the clock reference and determine whether a voltage level of the regulation signal is within a range. If the voltage level of the regulation signal is within the range, the regulation circuit may generate a switch signal. The switch may adjust a voltage level of the pre-regulation signal based on the switch signal.

A voltage regulator is provided wherein electricity flows through a second transistor in an operating state in which a control unit) applies an operating voltage to a base of the second transistor. A Zener diode sets, in the operating state, a voltage of a second conductive path to a voltage corresponding to a voltage across the Zener diode. A current corresponding to an addition value obtained by adding a value of a current flowing through a second resistor portion in the operating state, a value of a current flowing through a third resistor portion in the operating state, and a value of a current flowing through the Zener diode in the operating state flows through a ground-side resistor portion. A control unit stops the output of the operating voltage when a voltage of the second conductive path is lower than or equal to a threshold value.

A voltage regulator is provided wherein electricity flows through a second transistor in an operating state in which a control unit) applies an operating voltage to a base of the second transistor. A Zener diode sets, in the operating state, a voltage of a second conductive path to a voltage corresponding to a voltage across the Zener diode. A current corresponding to an addition value obtained by adding a value of a current flowing through a second resistor portion in the operating state, a value of a current flowing through a third resistor portion in the operating state, and a value of a current flowing through the Zener diode in the operating state flows through a ground-side resistor portion. A control unit stops the output of the operating voltage when a voltage of the second conductive path is lower than or equal to a threshold value.