Abstract: A PFC switching power conversion circuit providing low THD, including: a bridge rectifier for providing an input voltage according to an AC voltage; an electromagnetic interference filtering circuit for providing a line voltage according to the input voltage; a switching power converter for converting the line voltage to an output voltage or current under a control of a driving voltage, the driving voltage causing a switching current to flow through a main inductor; and a controller for receiving and processing at least one feedback signal from the switching power converter to generate the driving voltage in a constant on-time manner, the controller including an off-time detector and a timer, the off-time detector being used to detect decreasing periods of the switching current to determine respective off-time periods, and the timer being used to set a minimum limit on the respective off-time periods.

Abstract: A dimmable switching mode LED driving circuit without phase angle measurement, including: a dimmer circuit for providing a phase-cut AC voltage; a bridge rectifier providing an input voltage by rectifying the phase-cut AC voltage; an electromagnetic interference filtering and energy storing circuit providing a line voltage according to the input voltage; a switching power converter converting the line voltage to an output current for an LED load under a control of a driving voltage; and a control unit including an on-time controller for operating in a constant on-time mode to determine an on time, where the on-time controller includes a voltage limiting circuit, a saw-tooth signal generator, and a comparison circuit to set a maximum limit on the on time.

Abstract: A dimmable switching mode LED driving circuit without phase angle measurement, including: a dimmer circuit for providing a phase-cut AC voltage; a bridge rectifier providing an input voltage by rectifying the phase-cut AC voltage; an electromagnetic interference filtering and energy storing circuit providing a line voltage according to the input voltage; a switching power converter converting the line voltage to an output current for an LED load under a control of a driving voltage; and a control unit using at least one feedback signal to perform a pulse width modulation operation to determine an on time for the switching voltage; wherein the control unit includes an on-time controller and a timer, the on-time controller determining the on time according to the at least one feedback signal, and the timer setting a maximum limit on the on time.

Abstract: A level shifter capable of pulse filtering and a bridge driver using the same, the level shifter capable of pulse filtering being used for up shifting a first clock signal and a second clock signal to provide a set signal and a reset signal, and for preventing noise on the first clock signal or on the second clock signal from altering the states of the set signal and the reset signal.

Abstract: A DC-DC converter is provided. The DC-DC converter a power stage includes a first high side driver and a protecting circuit including a second high side driver, wherein the first high side driver and the second high side driver are connected in parallel, and operate in complementary.

Abstract: A pulse filter and a bridge driver using the same, the pulse filter including: a first NMOS transistor, having a drain coupled to a first PMOS transistor for providing a reset signal, a gate coupled to a second reset signal, and a source coupled to a second set signal; a second NMOS transistor, having a drain coupled to a second PMOS transistor for providing a set signal, a gate coupled to the second set signal, and a source coupled to the second reset signal; a third NMOS transistor, having a drain coupled to the second set signal, a gate coupled to the second reset signal, and a source coupled to a second power line; and a fourth NMOS transistor, having a drain coupled to the second reset signal, a gate coupled to the second set signal, and a source coupled to the second power line.