摘要:
A bridgeless PFC (power factor correction) converter with improved efficiency is disclosed. The bridgeless PFC converter comprises: input terminals configured to receive an input AC power supply; an output terminal configured to provide power supply; a high frequency bridge arm comprising a first switch and a third switch coupled between the output terminal and a ground node; a low frequency bridge arm comprising a second switch and a fourth switch coupled between the output terminal and the ground node; an inductor coupled between the input AC power supply and the high frequency bridge arm; and a control circuit configured to control the switching of switches in the high frequency bridge arm and the low frequency bridge arm.
摘要:
A bridgeless PFC (power factor correction) converter with improved efficiency is disclosed. The bridgeless PFC converter comprises: a first input terminal and a second input terminal configured to receive an input AC signal; an output terminal; an inductor set comprising N inductors, wherein a first terminal of each inductor is coupled to the first input terminal; and an output stage comprising (N+1) switching circuits coupled between the output terminal and a ground node.
摘要:
A bridgeless PFC (power factor correction) converter with improved efficiency is disclosed. The bridgeless PFC converter comprises: a first input terminal and a second input terminal configured to receive an input AC signal; an output terminal; an inductor set comprising N inductors, wherein a first terminal of each inductor is coupled to the first input terminal; and an output stage comprising (N+1) switching circuits coupled between the output terminal and a ground node.
摘要:
The present invention provides a switching regulator with frequency limitation and method thereof. The switching frequency of the switching regulator is limited through setting of a minimum off time, so as to improve the efficiency and EMI distribution of the switching regulator.
摘要:
A switching regulator with frequency limitation comprises a switch, a current sensing circuit, a voltage feedback circuit, a control circuit and a frequency limitation circuit. The current sensing circuit senses the current flowing through the switch and generating a current sensing signal representative of it. The voltage feedback circuit senses the output signal of the switching regulator and generates a feedback signal accordingly. The control circuit compares the current sensing signal with the feedback signal and turns off the switch based on the comparison result. The frequency limitation circuit is electrically coupled to the control circuit to limit the switching frequency of the switch.
摘要:
A CCFL inverter circuit integrates a feedback circuit and protection circuit together. For both in-phase and out-of-phase applications, sensed lamp voltages can be used for open lamp and short lamp detection and sensed currents can be used for open lamp detection. The driving circuit adjusts the open lamp frequency by using a duty cycle control signal so that the driving circuit can always achieve the desired lamp voltage gain.
摘要:
A dual ended driver circuit for a LCD backlight is disclosed. The circuit comprises a master board and a slave board, which provides a first output drive signal and a second output drive signal to either end of a lamp set, respectively. The circuit only uses one control chip to synchronize and make symmetrical the first output drive signal and the second output drive signal.
摘要:
The present technology discloses a package for a synchronous rectifier module, and also discloses synchronous rectification circuits and power supply adapters. The synchronous rectification circuit co-packages the synchronous rectifier and the driver into one single package. The single package simplifies the external circuitry and reduces potential electromagnetic interferences.
摘要:
The present invention discloses a DC/AC converter in the backlight power supply system using cold cathode fluorescent lamp (CCFL). The DC/AC converter comprises a front end DC/DC converter, a full-bridge or half bridge inverter, and a piezoelectric transformer. Even with a wide range of input voltages, the front end DC/DC converter produces a predetermined DC voltage or a DC voltage with a predetermined small range and the cascaded inverter operates with a switching frequency close to the resonant frequency of the piezoelectric transformer, which helps the backlight power supply system achieve high efficiency.
摘要:
A CCFL inverter circuit integrates a feedback circuit and protection circuit together. For both in-phase and out-of-phase applications, sensed lamp voltages can be used for open lamp and short lamp detection and sensed currents can be used for open lamp detection. The driving circuit adjusts the open lamp frequency by using a duty cycle control signal so that the driving circuit can always achieve the desired lamp voltage gain.