A battery charging circuit can include: a primary rectifier circuit configured to rectify an input AC voltage into a rectified voltage signal; a DC-DC converter configured to generate a charging current according to the rectified voltage signal, in order to charge a battery; a control circuit configured to adjust the charging current by controlling an operation state of the DC-DC converter according to a charging requirement, in order to make an average value of the charging current meet the charging requirement; and where the charging current is controlled to be zero when an absolute value of the input AC voltage is lower than a predetermined threshold.

The present description concerns a converter comprising an AC-DC conversion stage comprising a first thyristor, a first power supply circuit delivering a first reference voltage between a first node and a second node, and a second power supply circuit delivering a second reference voltage between third and fourth nodes, the cathode of the first thyristor being coupled to the first node of the first power supply circuit by a first switch and being connected to the fourth node, the second power supply circuit comprising a first rectifying element coupled to the second node of the first power supply circuit and coupled to the third node.

A switching device is provided. The apparatus includes a switching circuit and a noise filter. The switching circuit is capable of switching a connection destination of a first power conversion circuit other than a second power conversion circuit among the plurality of power conversion circuits between a phase corresponding to the first power conversion circuit and a certain phase of the external power supply. The second power conversion circuit corresponds to the certain phase of the external power supply. In the noise filter, a capacitor is provided on a side of the multiple-phase AC supply of the switching circuit.

A power supply circuit includes a power converter, an input voltage source, and a clamping circuit. The power converter has an input pin, an output pin, and an enable pin. The input voltage source is electrically connected to the input pin, and provides an input voltage to the input pin. The clamping circuit is electrically connected to the enable pin of the power converter. When the input voltage increases to at least a threshold input voltage, the clamping circuit is configured to activate the power converter to provide an output voltage at the output pin. When the input voltage decreases below the threshold input voltage, the clamping circuit is configured to deactivate the power converter and prevent the power converter from being re-activated within a predefined time period.

A two-wire load control device (such as, a dimmer switch) for controlling the amount of power delivered from an AC power source to an electrical load (such as, a high-efficiency lighting load) includes a thyristor coupled between the source and the load, a gate coupling circuit coupled between a first main load terminal and the gate of the thyristor, and a control circuit coupled to a control input of the gate coupling circuit. The control circuit generates a drive voltage for causing the gate coupling circuit to conduct a gate current to thus render the thyristor conductive at a firing time during a half cycle of the AC power source, and to allow the gate coupling circuit to conduct the gate current at any time from the firing time through approximately the remainder of the half cycle, where the gate coupling circuit conducts approximately no net average current to render and maintain the thyristor conductive.

A two-wire load control device (such as, a dimmer switch) for controlling the amount of power delivered from an AC power source to an electrical load (such as, a high-efficiency lighting load) includes a thyristor coupled between the source and the load, a gate coupling circuit coupled between a first main load terminal and the gate of the thyristor, and a control circuit coupled to a control input of the gate coupling circuit. The control circuit generates a drive voltage for causing the gate coupling circuit to conduct a gate current to thus render the thyristor conductive at a firing time during a half cycle of the AC power source, and to allow the gate coupling circuit to conduct the gate current at any time from the firing time through approximately the remainder of the half cycle, where the gate coupling circuit conducts approximately no net average current to render and maintain the thyristor conductive.

An inverter type engine generator includes an alternator; and a converter composed of the a three-phase rectifying bridge circuit including an upper and lower three sets of elements, and converting three-phase alternating current output from the alternator into direct current. The upper and lower three sets of elements of the three-phase rectifying bridge circuit of the converter are configured such that upper elements are configured at least from duty-controllable diode elements, and lower elements are configured at least from duty-controllable switching elements having diodes.

Intelligent electrical switches are provided to implement multi-way circuits using two or more intelligent electrical switches for controlling power to a load.

Intelligent electrical switches are provided to implement multi-way circuits using two or more intelligent electrical switches for controlling power to a load.

Provided are a power supply circuit, a power supply device and a control method. The power supply circuit includes a primary rectifier unit, a modulation unit, a transformer, a secondary rectifier and filtering unit, a current feedback unit, and a control unit. The power supply circuit removes a liquid electrolytic capacitor at a primary side. Moreover, the control unit may determine a type of a voltage of input alternating current, and set a current limit value in the current feedback unit according to the type of the voltage of the alternating current.