Abstract: A switch having a drain, a source, and a control. The switch comprising a depletion-mode transistor including a first, a second, and a control terminal and an enhancement-mode transistor including a first, a second, and a control terminal. The first terminal of the depletion-mode transistor is the drain of the switch and the control of the depletion-mode transistor is coupled to the source of the switch. The control of the enhancement-mode transistor is coupled to the control of the switch, the second terminal of the enhancement-mode transistor is the source of the switch. The switch comprises a clamp circuit to clamp a voltage of the first terminal of the enhancement-mode transistor to a threshold, the clamp circuit comprises a resistor and a pn-junction device coupled between the first and second terminals of the enhancement-mode transistor and between the second terminal and the control of the depletion-mode transistor.

Abstract: A switch having a drain, a source, and a control. The switch comprising a depletion-mode transistor including a first, a second, and a control terminal and an enhancement-mode transistor including a first, a second, and a control terminal. The first terminal of the depletion-mode transistor is the drain of the switch and the control of the depletion-mode transistor is coupled to the source of the switch. The control of the enhancement-mode transistor is coupled to the control of the switch, the second terminal of the enhancement-mode transistor is the source of the switch. The switch comprises a clamp circuit to clamp a voltage of the first terminal of the enhancement-mode transistor to a threshold, the clamp circuit comprises a resistor and a pn-junction device coupled between the first and second terminals of the enhancement-mode transistor and between the second terminal and the control of the depletion-mode transistor.

Abstract: A switch having a drain, a source, and a control. The switch comprising a depletion-mode transistor including a first, a second, and a control terminal and an enhancement-mode transistor including a first, a second, and a control terminal. The first terminal of the depletion-mode transistor is the drain of the switch and the control of the depletion-mode transistor is coupled to the source of the switch. The control of the enhancement-mode transistor is coupled to the control of the switch, the second terminal of the enhancement-mode transistor is the source of the switch. The switch comprises a clamp circuit to clamp a voltage of the first terminal of the enhancement-mode transistor to a threshold, the clamp circuit comprises a resistor and a pn-junction device coupled between the first and second terminals of the enhancement-mode transistor and between the second terminal and the control of the depletion-mode transistor.

Abstract: A switch having a drain, a source, and a control. The switch comprising a depletion-mode transistor including a first, a second, and a control terminal and an enhancement-mode transistor including a first, a second, and a control terminal. The first terminal of the depletion-mode transistor is the drain of the switch and the control of the depletion-mode transistor is coupled to the source of the switch. The control of the enhancement-mode transistor is coupled to the control of the switch, the second terminal of the enhancement-mode transistor is the source of the switch. The switch comprises a clamp circuit to clamp a voltage of the first terminal of the enhancement-mode transistor to a threshold, the clamp circuit comprises a resistor and a pn-junction device coupled between the first and second terminals of the enhancement-mode transistor and between the second terminal and the control of the depletion-mode transistor.

Abstract: A switch having a drain terminal, a source terminal and a control terminal. The switch comprises a normally-on device including a first terminal, a second terminal, and a control terminal, a normally-off device including a first terminal, a second terminal, and a control terminal, and a clamp circuit. The first terminal of the normally-on device is the drain terminal of the switch and the control terminal of the normally-on device is coupled to the source terminal of the switch. The control terminal of the normally-off device is coupled to the control terminal of the switch. The second terminal of the normally-off device is the source terminal of the switch, and the first terminal of the normally-off device is coupled to the second terminal of the normally-on device. The clamp circuit coupled across the normally-off device and comprises a first transistor coupled to the first terminal of the normally-off device.

Abstract: A switch having a drain terminal, a source terminal and a control terminal. The switch comprises a normally-on device including a first terminal, a second terminal, and a control terminal, a normally-off device including a first terminal, a second terminal, and a control terminal, and a clamp circuit. The first terminal of the normally-on device is the drain terminal of the switch and the control terminal of the normally-on device is coupled to the source terminal of the switch. The control terminal of the normally-off device is coupled to the control terminal of the switch. The second terminal of the normally-off device is the source terminal of the switch, and the first terminal of the normally-off device is coupled to the second terminal of the normally-on device. The clamp circuit coupled across the normally-off device and comprises a first transistor coupled to the first terminal of the normally-off device.

Abstract: A switch having a first terminal, a second terminal and a control terminal. The switch includes a normally-on device with a first terminal, a second terminal, and a control terminal. The first terminal of the normally-on device is the first terminal of the switch. The control terminal of the normally-on device is coupled to the second terminal of the switch. A normally-off device includes a first terminal, a second terminal, and a control terminal. The control terminal of the normally-off device is coupled to the control terminal of the switch. The second terminal of the normally off-device is the second terminal of the switch. The first terminal of the normally-off device is coupled to the second terminal of the normally-on device. A clamp circuit is coupled across the normally-off device. The clamp circuit is coupled to clamp a voltage of the first terminal of the normally-off device to a threshold.

Abstract: A switch having a first terminal, a second terminal and a control terminal. The switch includes a normally-on device with a first terminal, a second terminal, and a control terminal. The first terminal of the normally-on device is the first terminal of the switch. The control terminal of the normally-on device is coupled to the second terminal of the switch. A normally-off device includes a first terminal, a second terminal, and a control terminal. The control terminal of the normally-off device is coupled to the control terminal of the switch. The second terminal of the normally off-device is the second terminal of the switch. The first terminal of the normally-off device is coupled to the second terminal of the normally-on device. A clamp circuit is coupled across the normally-off device. The clamp circuit is coupled to clamp a voltage of the first terminal of the normally-off device to a threshold.

Abstract: A cascode switch circuit includes a normally-on device cascode coupled to a normally-off device between first and second terminals of the cascode switch circuit. A leakage clamp circuit is coupled between first and second terminals of the normally-off device. The leakage clamp circuit is coupled to clamp a voltage at an intermediate terminal between the normally-on device and the normally-off device at a threshold voltage level. The leakage clamp circuit is further coupled to clamp a voltage between the second terminal of the normally-on device and the control terminal of the normally-on device at the threshold voltage level to keep the normally-on device off when the normally-on device and the normally-off device are off.

Abstract: A cascode switch circuit includes a normally-on device cascode coupled to a normally-of device between first and second terminals of the cascode switch circuit. A leakage clamp circuit is coupled between first and second terminals of the normally-off device. The leakage clamp circuit is coupled to clamp a voltage at an intermediate terminal between the normally-on device and the normally-off device at a threshold voltage level. The leakage clamp circuit is further coupled to clamp a voltage between the second terminal of the normally-on device and the control terminal of the normally-on device at the threshold voltage level to keep the normally-on device off when the normally-on device and the normally-off device are off.

Abstract: A power supply includes a PFC (power factor correction) converter that has an input and an output. The PFC converter input is coupled to an input of the power supply. The power supply also includes a resonant mode converter that has an input and an output. The resonant mode converter input is coupled to the PFC converter output and the resonant mode output is coupled to an output of the power supply. A control unit is also included in the power supply and is coupled to receive a feedback signal that is representative of the output of the power supply. The control unit is coupled to provide control signals coupled to control switches of the resonant mode converter at a controlled switching frequency to control the output of the power supply. The control unit is further coupled to provide a PFC control signal coupled to control a switch of the PFC converter at a switching frequency that is harmonically related to the controlled switching frequency.

Abstract: A power supply includes a PFC (power factor correction) converter that has an input and an output. The PFC converter input is coupled to an input of the power supply. The power supply also includes a resonant mode converter that has an input and an output. The resonant mode converter input is coupled to the PFC converter output and the resonant mode output is coupled to an output of the power supply. A control unit is also included in the power supply and is coupled to receive a feedback signal that is representative of the output of the power supply. The control unit is coupled to provide control signals coupled to control switches of the resonant mode converter at a controlled switching frequency to control the output of the power supply. The control unit is further coupled to provide a PFC control signal coupled to control a switch of the PFC converter at a switching frequency that is harmonically related to the controlled switching frequency.

Abstract: A control unit controls cascaded PFC and LLC converters, the LLC converter having an input coupled to an output, of the PFC converter and providing an output voltage that decreases with increasing switching frequency. The control unit produces a sawtooth waveform with a linear ramp for controlling the LLC converter switching frequency, and hence its output voltage, in dependence upon a feedback signal. It also produces for the PFC converter a PWM signal with a frequency that is the same as or an integer fraction of the LLC converter switching frequency, by comparing two thresholds with the linear ramp in respective different cycles of the sawtooth waveform to turn on and off a switch of the PFC converter during these different cycles. Logic circuits prevent PFC converter switch transitions from occurring simultaneously with switching transitions of the LLC converter.

Abstract: A control unit controls cascaded PFC and LLC converters, the LLC converter having an input coupled to an output, of the PFC converter and providing an output voltage that decreases with increasing switching frequency. The control unit produces a sawtooth waveform with a linear ramp for controlling the LLC converter switching frequency, and hence its output voltage, in dependence upon a feedback signal. It also produces for the PFC converter a PWM signal with a frequency that is the same as or an integer fraction of the LLC converter switching frequency, by comparing two thresholds with the linear ramp in respective different cycles of the sawtooth waveform to turn on and off a switch of the PFC converter during these different cycles. Logic circuits prevent PFC converter switch transitions from occurring simultaneously with switching transitions of the LLC converter.