A power transistor and a cascode transistor are connected in series. A driver circuit has an output driving a control terminal of the power transistor. The driver circuit has a first power supply node coupled to receive a floating voltage that is also applied to a control terminal of the cascode transistor. A variable voltage generator generates the floating voltage. The floating voltage track either a power supply voltage or a reference voltage over a first range of voltage levels for the power supply voltage. The floating voltage further satisfies a ratio metric relationship dependent on the power supply voltage and reference voltage over a second range of voltage levels for said power supply voltage.

Provided is a semiconductor device comprising a high-side switching device, a low-side switching device, a high-side driver configured to turn on/off the high-side switching device, a low-side driver configured to turn on/off the low-side switching device, a high-side driving external terminal configured to supply a power supply voltage for driving the high-side driver, and a protection circuit section connected to the high-side driving external terminal. The high-side driver may include a reference potential terminal set to a reference potential of the high-side driver. The protection circuit section may be connected between the high-side driving external terminal and the reference potential terminal.

Power supply circuit having low quiescent current for a bypass mode. One example power supply circuit generally includes a transistor; a switching node coupled to a source of the transistor; a power supply rail; a capacitor having a first terminal coupled to the power supply rail and having a second terminal coupled to the switching node; a gate driver having an output coupled to a gate of the transistor, having a first power input coupled to the power supply rail, and having a second power input coupled to the switching node; logic having a first input coupled to the first terminal of the capacitor, having a second input coupled to the second terminal of the capacitor, and having a first output; and a pullup circuit having a control input coupled to a second output of the logic and having an output coupled to the gate of the transistor.

There is presented a driver and a corresponding method for driving a p-type power switch. The driver includes a capacitor coupled to a control terminal of the power switch. The driver is configured to apply a control voltage to the control terminal and to connect the control terminal to ground to reduce the control voltage down to a target value to switch the power switch on. When identifying that the control voltage has reached the target value, the driver disconnects the control terminal from ground. The driver may be used in various circuits including switching power converters, audio amplifiers and charge-pump circuits.

A circuit comprises a gate driver having a supply voltage terminal and configured to generate an output at an output terminal based on an input. A voltage multiplexer is configured to connect a first voltage terminal to the supply voltage terminal responsive to a voltage select signal having a first value and connect a second voltage terminal to the supply voltage terminal responsive to the voltage select signal having a second value. First logic is configured to generate a fault signal responsive to detecting one of a first fault condition associated with operation of the gate driver or a second fault condition associated with operation of the gate driver and generate the voltage select signal having the second value based on the fault signal. Second logic is configured to generate the voltage select signal having the second value after a predetermined delay period based on a value of the input.

A switching circuit comprises a radio frequency (RF) switch, a gate resistor, a voltage source, a transmission gate, and coupling circuitry configured to couple a gate of the RF switch, a first side of the gate resistor, and the transmission gate at a first node and the voltage source, a second side of the gate resistor, and the transmission gate at a second node.

A switching circuit includes a high-side transistor and a low-side transistor, each of which is of an N-channel type. A switch and a rectifying element of a PMOS transistor are provided in series between a constant voltage line through which a constant voltage is supplied and a bootstrap line. A comparison circuit operates using a high-side power supply voltage, which is a potential difference between the bootstrap line and a switching line, as a power supply to generate a detection signal indicating a magnitude relationship between the high-side power supply voltage and a threshold voltage. A level shift circuit level-shifts the detection signal down to a signal of which a ground voltage is low. A PMOS driver drives the switch asynchronously with switching of the low-side transistor in response to an output of the level shift circuit.

A circuit device includes a control circuit configured to control a transistor current based on a detected temperature. The detected temperature is a temperature detected by a temperature sensor circuit that detects a temperature of a transistor. The transistor charges a load to which a power supply voltage is supplied. The transistor current is a current flowing through the transistor during charging. The control circuit reduces the transistor current when the detected temperature is higher than a first threshold value, and increases the transistor current when the detected temperature is lower than a second threshold value lower than the first threshold value.

A boot charge circuit for charging a boot capacitor of a switching power converter with upper and lower switches including pulse circuitry that provides a boot refresh pulse in response to a pulse control signal transitioning to an active state to turn on the lower switch for a duration of the boot refresh pulse, and gate circuitry that prevents activation of the upper switch until after completion of the boot refresh pulse in response to the transitioning of the pulse control signal. The boot refresh pulse has a negligible duration relative to each switching cycle yet sufficient to charge the boot capacitor to enable a driver to turn on the upper switch. A load monitor may be included to disable the pulse circuitry from providing the boot refresh pulse during higher load levels.

A level-shifting output buffer has cascode transistors with varying rather than fixed gate bias voltages. An adaptive regulator bypasses the I/O pad voltage to a regulator output when the I/O begins switching, but later clamps the regulator output to a middle bias voltage. The regulator output can be applied to a supply terminal of a buffer that drives the gate of the cascode transistor. Since the adaptive regulator follows the I/O pad voltage as switching begins, a voltage boost is provided to the gates of the cascode transistors, allowing for higher currents or smaller cascode transistors and preventing over-voltage stress. The adaptive regulator has an n-channel bypass transistor between the I/O pad and the regulator output, and an n-channel clamp transistor between the regulator output and the middle bias, with a gate driven from the I/O pad by either a p-channel gate-biasing transistor or an n-channel gate-biasing transistor.