In a general aspect, a circuit can include a pass device configured to receive an input voltage and provide an output voltage. The circuit can further include a current sink coupled with a control terminal of the pass device, the current sink being configured to discharge the control terminal of the pass device to limit the output voltage in response to the input voltage exceeding a threshold voltage. The circuit can also include a switch coupled in series with the current sink, the switch being configured to enable the current sink in response to the input voltage exceeding the threshold voltage.

A controller for a system includes a first control section and a second control section. The system includes an electrical actuator, a switch switching the electrical actuator between a power supply state and a power cutoff state, and a drive section driving the switch. The drive section outputs, to the switch, a drive signal to drive the switch based on a command signal for switching of the switch. The first control section determines a switch state based on the command signal, and the second control section determines a switch state based on the drive signal. At least one of the first control section and the second control section determines the electrical actuator to be in the power supply state on the condition that the first control section determines the switch to be in the power supply state, and the second control section also determines the switch to be in the power supply state.

A controller for a system includes a first control section and a second control section. The system includes an electrical actuator, a switch switching the electrical actuator between a power supply state and a power cutoff state, and a drive section driving the switch. The drive section outputs, to the switch, a drive signal to drive the switch based on a command signal for switching of the switch. The first control section determines a switch state based on the command signal, and the second control section determines a switch state based on the drive signal. At least one of the first control section and the second control section determines the electrical actuator to be in the power supply state on the condition that the first control section determines the switch to be in the power supply state, and the second control section also determines the switch to be in the power supply state.

During an ON period of a high breakdown voltage switch provided within an ON period of a semiconductor switching element, a detection circuit outputs to a predetermined node a voltage obtained by dividing an inter-terminal voltage by a plurality of resistor elements. A voltage comparison circuit outputs a detection signal indicating whether or not the inter-terminal voltage is greater than a predetermined determination voltage based on a comparison between the voltage of the predetermined node and a predetermined DC voltage. The high breakdown voltage switch has a breakdown voltage greater than a potential difference between a high potential and a low potential during an OFF period.

An integrated circuit includes a power-on reset (POR) circuit and a digital logic circuit. The POR has first and second control outputs. The POR circuit is configured to generate a first control signal on the first control output responsive to a supply voltage on the supply voltage node exceeding a first threshold voltage and is configured to generate a second control signal on the second control output responsive to the supply voltage exceeding a second threshold voltage. The digital logic circuit has a first control input coupled to the first control output of the POR circuit and has a second control input coupled to the second control output of the POR circuit. The digital logic circuit is configured to initiate a first read transaction responsive to assertion of the first control signal and to initiate a second read transaction responsive to assertion of the second control signal.

An integrated circuit includes a power-on reset (POR) circuit and a digital logic circuit. The POR has first and second control outputs. The POR circuit is configured to generate a first control signal on the first control output responsive to a supply voltage on the supply voltage node exceeding a first threshold voltage and is configured to generate a second control signal on the second control output responsive to the supply voltage exceeding a second threshold voltage. The digital logic circuit has a first control input coupled to the first control output of the POR circuit and has a second control input coupled to the second control output of the POR circuit. The digital logic circuit is configured to initiate a first read transaction responsive to assertion of the first control signal and to initiate a second read transaction responsive to assertion of the second control signal.

A voltage supervisor includes a first transistor coupled between a first supply voltage and a second supply voltage. The voltage supervisor includes a second transistor coupled between the first supply voltage and the second supply voltage. The voltage supervisor is configured to provide a first current proportional to a difference in gate-to-source voltages of the first transistor and the second transistor. The voltage supervisor is also configured to provide a second current proportional to a difference in the first supply voltage and the difference in gate-to-source voltages of the first transistor and the second transistor. The voltage supervisor is configured to compare the first current to the second current to determine a voltage value that changes a state responsive to the first supply voltage crossing a threshold.

A control circuit includes: a transistor controller that controls a voltage at a gate terminal of a field effect transistor in accordance with a difference in voltage between a source terminal and a drain terminal of the field effect transistor connected so that a body diode is in a forward direction; and a current controller that reduces an operating current for operating the transistor controller when a load connected via the source terminal of the field effect transistor is light, and increases the operating current when the load is heavy.

A communication system includes a supply generator configured to generate a modulated supply according to a data transmission; a light emitting diode (LED) emulator including an emulator input coupled to the supply generator and an emulator output configured to output a sense voltage, wherein the emulator input is configured to receive a forward current derived from the modulated supply and translate the forward current into the sense voltage; a voltage comparator coupled to the emulator output and configured to receive the sense voltage and translate the sense voltage into a modulated output signal based on a communication voltage threshold; and a transmitter coupled to a comparator output and configured to receive the modulated output signal and generate a communication signal according to the data transmission based on the modulated output signal.

In certain embodiments, driver circuitry generates drive signals to drive driven circuitry to transition between first and second states. The driver circuitry has a first-to-second driver circuit that generates a first drive signal to drive the driven circuitry to transition from the first state to the second state and a second-to-first driver circuit that generates a second drive signal to drive the driven circuitry to transition from the second state to the first state. The driver circuitry includes two complementary triggered current pulse generators (described in U.S. Pat. No. 10,554,206) that combine to efficiently provide switch drive for a FET or other reactive load. The triggered drive has fast edges for low switching losses. In certain embodiments, the low power triggered drive circuitry can respond to a slowly changing feedback signal to switch a FET so as to regulate a power converter output.