Abstract: A power switch device with cascode structure provides better performance with simple design. It has a normally-on device and a normally-off device coupled in series. A resistor is coupled to a control terminal of the normally-on device; and a capacitor is coupled between a control terminal of the normally-off device and the control terminal of the normally-on device.

Abstract: A control circuit for switching converter has an ON signal generating circuit, an OFF signal generating circuit, a first comparator, a second comparator and a logic circuit. The switching converter has a high switch and a low side switch connected in series. The ON signal generating circuit provides an ON signal based on a reference signal and a feedback signal. The OFF signal generating circuit provides an OFF signal. The first comparator provides a first comparing signal based on a comparing result between a first threshold and a current through the high side switch. The second comparator provides a second comparing signal based on a comparing result between a second threshold and a current through the low side switch. The logic circuit provides a first switching signal to control the high side switch ON and OFF and a second switching signal to control the low side switch ON and OFF.

Abstract: A power converter having a soft-off control circuit and a variable reference signal generation module and associated method for controlling the power converter. The variable reference signal generation module is configured to provide a variable reference signal to the power converter. The soft-off control circuit is configured to determine whether an input voltage of the power converter exceeds an over-voltage threshold, and to control the variable reference signal to increase once the input voltage reaches the over-voltage threshold and to decrease when the input voltage is lower than the over-voltage threshold. The power converter can regulate an output voltage to increase with the increase of the variable reference signal and to decrease with the decrease of the variable reference signal so that during a soft-off procedure the input voltage may not exceed the over-voltage threshold, enabling the power converter to be safely shut off.

Abstract: A control circuit for switching converter has an ON signal generating circuit, an OFF signal generating circuit, a first comparator, a second comparator and a logic circuit. The switching converter has a high switch and a low side switch connected in series. The ON signal generating circuit provides an ON signal based on a reference signal and a feedback signal. The OFF signal generating circuit provides an OFF signal. The first comparator provides a first comparing signal based on a comparing result between a first threshold and a current through the high side switch. The second comparator provides a second comparing signal based on a comparing result between a second threshold and a current through the low side switch. The logic circuit provides a first switching signal to control the high side switch ON and OFF and a second switching signal to control the low side switch ON and OFF.

Abstract: A power converter having a soft-off control circuit and a variable reference signal generation module and associated method for controlling the power converter. The variable reference signal generation module is configured to provide a variable reference signal to the power converter. The soft-off control circuit is configured to determine whether an input voltage of the power converter exceeds an over-voltage threshold, and to control the variable reference signal to increase once the input voltage reaches the over-voltage threshold and to decrease when the input voltage is lower than the over-voltage threshold. The power converter can regulate an output voltage to increase with the increase of the variable reference signal and to decrease with the decrease of the variable reference signal so that during a soft-off procedure the input voltage may not exceed the over-voltage threshold, enabling the power converter to be safely shut off.