Abstract: According to some embodiments, AC chopping circuit includes a switching circuit, a synchronizing signal generating circuit, a switch driving circuit and an auxiliary power supplying circuit. In some examples, the switching circuit are coupled to an AC power source and a load. In certain examples, the synchronizing signal generating circuit provides a synchronizing signal which is related to a polarity of the AC power source. In some examples, the switching circuit is controlled based at least in part on the synchronizing signal.

Abstract: According to some embodiments, AC chopping circuit includes a switching circuit, a synchronizing signal generating circuit, a switch driving circuit and an auxiliary power supplying circuit. In some examples, the switching circuit are coupled to an AC power source and a load. In certain examples, the synchronizing signal generating circuit provides a synchronizing signal which is related to a polarity of the AC power source. In some examples, the switching circuit is controlled based at least in part on the synchronizing signal.

Abstract: According to some embodiments, AC chopping circuit includes a switching circuit, a synchronizing signal generating circuit, a switch driving circuit and an auxiliary power supplying circuit. In some examples, the switching circuit are coupled to an AC power source and a load. In certain examples, the synchronizing signal generating circuit provides a synchronizing signal which is related to a polarity of the AC power source. In some examples, the switching circuit is controlled based at least in part on the synchronizing signal.

Abstract: According to some embodiments, AC chopping circuit includes a switching circuit, a synchronizing signal generating circuit, a switch driving circuit and an auxiliary power supplying circuit. In some examples, the switching circuit are coupled to an AC power source and a load. In certain examples, the synchronizing signal generating circuit provides a synchronizing signal which is related to a polarity of the AC power source. In some examples, the switching circuit is controlled based at least in part on the synchronizing signal.

Abstract: A stepless motor driving circuit provides a sinusoidal shaped chopping signal for driving a motor. The driving circuit has: a switch circuit having an input which receives a rectified signal rectified from a sinusoidal AC signal and having a first output and a second output where the motor is coupled between; a synchronizing signal generating circuit which generates a synchronizing signal relating to the sinusoidal AC signal; and a switch driving circuit which selects and chops at least one switch in the switch circuit according to the synchronizing signal, and to form the sinusoidal shaped chopping signal which is corresponding to the sinusoidal AC signal.

Abstract: A stepless motor driving circuit provides a sinusoidal shaped chopping signal for driving a motor. The driving circuit has: a switch circuit having an input which receives a rectified signal rectified from a sinusoidal AC signal and having a first output and a second output where the motor is coupled between; a synchronizing signal generating circuit which generates a synchronizing signal relating to the sinusoidal AC signal; and a switch driving circuit which selects and chops at least one switch in the switch circuit according to the synchronizing signal, and to form the sinusoidal shaped chopping signal which is corresponding to the sinusoidal AC signal.

Abstract: Connecting a load device to a power supply is described. A connection to a load device is detected on a communication link, where the load device is in a first power state. In response to detecting the connection to the load device, a bias power source is enabled to supply bias power on the communication link to the load device. Power information of the load device is received over the communication link. Power is supplied to the load device, based on the power information, to place the load device in a second power state.