Mornsun Guangzhou Science & Technology Co., Ltd.

Mornsun Guangzhou Science & Technology Limited

Xiangyang Yin

Junxi Su

Baojun Wang

Xiang Liu

Yuan Yuan

Shengbin Tang

Haizhou Wang

This disclosure provides a multi-mode control method for an active clamp flyback converter. In the flyback converter, the controller realizes mode switching between a trailing edge non-complementary mode, a leading edge non-complementary mode, and a leading edge non-complementary Burst mode of two driving signals after comparing a detection feedback voltage with the set mode switching threshold voltages. The disclosure adopts the trailing edge non-complementary mode to reduce a circulating current of the converter, uses the leading edge non-complementary mode to replace the ordinary flyback mode to improve light load efficiency, and uses the leading-edge non-complementary Burst mode at no-load to limit a peak current of a primary side in leading-edge non-complementary Burst mode to avoid generation of audio noise, and allowing a low no-load power consumption.

Multi-mode control method for active clamp flyback converter

A power-saving circuit for a contactor includes a coil drive circuit, and further includes a rectification and filtering circuit, a PFC circuit, an auxiliary power supply circuit, and a square wave generation circuit. The square wave generation circuit outputs a first square wave signal to the PFC circuit via a first output end according to a set timing sequence, and outputs a second square wave signal and a third square wave signal to the coil drive circuit via a second output end, so as to respectively control duty cycles of a first switch tube in the PFC circuit and a second switch tube in the coil drive circuit. The auxiliary power supply circuit supplies electric energy to the square wave generation circuit during a holding stage of the contactor. The rectification and filtering circuit is used for rectifying an input AC into a pulsating DC, and filtering an input narrow-pulse current into a smooth current to be outputted to the PFC circuit after eliminating higher harmonic components other than a fundamental frequency component of 50 Hz. The PFC circuit receives rectified and filtered electric energy, enables an effective value of the input current to change along with an input voltage, and outputs the input current to the coil drive circuit and the auxiliary power supply circuit. The coil drive circuit is used for controlling the current of a contactor coil. Wherein during a pull-in stage of the contactor, the PFC circuit does not work and the power-saving circuit provides a large current to the contactor coil to pull in; during a transition stage, the PFC circuit starts to work and the power-saving circuit controls the current of the contactor coil to decrease gradually; and during a holding stage of the contactor, the PFC circuit keeps working and the power-saving circuit controls the current of the contactor coil to be kept as a small current required for holding.

Power-saving circuit for contactor

The present application discloses a contactor coil control circuit, including a switch control circuit, a drive circuit, a fast turn-off circuit, a diode Da first MOS (Metal Oxide Semiconductor) transistor TRand a contactor coil. The fast turn-off circuit at least includes an MOS transistor TRor a triode; the cathode of the diode is connected to an input voltage VIN; the anode of the diode is connected to a first port of the fast turn-off circuit; a second port of the fast turn-off circuit is connected to the drain of the first MOS transistor; the source of the first MOS transistor is grounded; one end of the contactor coil Lis connected to an input voltage, and the other end of the contactor coil is connected to the drain of the first MOS transistor; a third port of the fast turn-off circuit is connected to an output port of the drive circuit; an input port of the drive circuit is connected to a first output port of the switch control circuit; and a second output port of the switch control circuit is connected to the gate of the first MOS transistor. On the premise of turning off the contactor quickly, the coil control circuit is lower in loss, adopts a fewer of devices, and is lower in cost and smaller in volume.

Contactor coil control circuit

An AC to DC circuit includes a rectifier circuit, a voltage detecting circuit, the current source and the output circuit. The rectifier circuit converts the AC power to pulsating DC. The constant current source provides current to the voltage detection circuit and to the control port of the output circuit. The current passing throughout the constant current source is the sum of the current flowing to the voltage detection circuit and to the output circuit. The voltage detection circuit increases with the instantaneous value of the output voltage of the rectifier circuit, it absorbs more current from the current provided by the constant current source and less current flows from the constant current source to the control port of the output circuit. The output circuit amplifies the current of the control port and outputs it to power the load. The AC to DC circuit of the present invention can rectify the portion of an alternating input voltage below a sine peak of the alternating current, working at a sine wave ascending area and a sine wave descending area, and it can carry a capacitive load.

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Guangdong, China

Xiangyang Yin