An image display apparatus is disclosed. The image display apparatus includes a display and a power supply configured to supply driving voltage to the display, wherein the power supply includes a converter to convert input AC voltage into DC voltage and a controller to control the converter, the converter includes a first leg including a first switching device and a second switching device connected to each other in series and a second leg including a first diode and a second diode connected to each other in series, the first diode and the second diode connected to the first leg in parallel, and the controller controls on time of the first switching device to gradually increase from a first level to a second level for a first period for which the input AC voltage rises after a zero crossing point.

A circuit for providing input surge protection in a digital input module, the circuit comprising a surge protection input stage, including a bridge rectifier coupled to receive the bidirectional input signal, and coupled to the unidirectional input of the digital input module. The bridge rectifier comprises TVS rectifiers TVS1 and TVS2, and diode rectifiers D2 and D3, intercoupled in a bridge rectifier configuration in which: TVS1 and TVS4 are transient voltage suppression diodes; and rectifiers D2 and D3 are rectifier diodes. Diodes TVS1 and TVS4 can be implemented as either respective unidirectional TVS diodes; or a single bidirectional TVS diode. The digital input module can be a digital input receiver, or a opto-isolator/coupler, or other digital input module.

The present disclosure relates to an AC-DC converter comprising: an AC side input port; a first DC connection and a second DC connection defining a DC side output port connectable to a load; an AC-DC rectifier having an AC rectifier side connected to the AC side input port and a DC rectifier side comprising a first DC rectifier connection and a second DC rectifier connection, wherein the first DC rectifier connection is connected to the first DC connection; a DC-AC converter having a first DC input and a second DC input, wherein the first DC input is connected to the second DC connection, and a first AC output and a second AC output, wherein the first AC output and the second AC output are connected to the AC side input port, or an AC-AC converter having a first AC input and a second AC input, wherein the first AC input is connected to the second DC connection, and a first AC output and a second AC output, wherein the first AC output and the second AC output are connected to the AC side input port. The disclosure further relates to a method of supplying power to a load by an AC-DC converter.

A power conversion device is provided. The power conversion device includes a bulk capacitor, a current limiting resistor in series with the bulk capacitor, and an inrush current control device configured to bypass the current limiting resistor when activated. The power conversion device also includes a bypass device in parallel with the current limiting resistor, configured to provide a low-resistance path to the bulk capacitor during a power surge.

Disclosed are a power stabilization circuit and a display device to which the power stabilization circuit is applied. The power stabilization circuit includes a thermistor provided on a first path through which an input power is supplied, to limit an inrush current of the power, a relay that provides a second path through which the power is supplied without passing through the thermistor, to allow the power to be transferred through the second path instead of the first path when a current is supplied, and a switching circuit that is switched to supply the current generated from the input power to the relay when an activation signal for activating at least one of a display and a backlight of the display is received.

The present disclosure provides a three-phase AC/DC converter aiming for low input current harmonic. The converter includes an input stage for receiving a three-phase AC input voltage, an output stage for at least one load, and one or more switching conversion stages, each stage including a plurality of half bridge modules. The switches in each module operate with a substantially fixed 50% duty cycle and are connected in a specific pattern to couple a DC-link and a neutral node of the input voltage. The AC/DC converter further includes one or more controllers adapted to vary the switching frequency of the switches in the switching conversion stages based on at least one of load voltage, load current, input voltage, and DC-link voltage. The converter can also include one or more decoupling stages, such as, inductive components adapted to decouple the output stage from the switching conversion stages.

A system includes: a pre-charge circuit configured to produce direct current (DC) electrical power; a common DC bus; and a plurality of inverters, each inverter including: a local DC bus; a capacitor network connected to the local DC bus; an electrical network connected to the local DC bus, the electrical network configured to generate an alternating current (AC) drive signal; and a plurality of switching assemblies, each switching assembly being associated with one of the inverters, and each switching assembly configured to control whether the local DC bus and the capacitor network of the associated inverter are electrically connected to the common DC bus or to the pre-charge circuit.

A frequency converter includes a rectifier on an input side and a support capacitor downstream of the rectifier. Input-side phases of the rectifier feed the backup capacitor via multiple half-bridges of the rectifier. The half-bridges have active switching elements and the rectifier is designed as a recovery rectifier, The input-side phases are connected to grid-side phases of a multiphase supply grid via an upstream circuit. Each grid-side phase is connected to one of the input-side phases within the upstream circuit via a respective phase capacitor. A control facility controls the active switching elements when a first charge state of the support capacitor is reached and input-side phase voltages are applied to the input-side phases via the active switching elements. Voltages running in the opposite direction to the grid-side phase voltages are applied to the grid-side phases to which the input-side phases are connected via the phase capacitors.

A power device is provided. The power device includes a current limiting resistor in series with a load, the current limiting resistor configured to provide a first current path to the load. The power device also includes an inrush current control device configured to provide a second current path to the load, the second current path configured to bypass the first current path in response to the inrush current control device being activated. The power device also includes a bypass device configured to provide a third current path to the load, the third current path configured to provide a low-resistance current path to the load during a power surge.

A power supply has a transformer with primary and secondary windings. A first terminal of the primary-winding is coupled to a power-input. A PFC includes a low-voltage circuit correcting power factor of the power signal, having a supply-input receiving a supply voltage during normal operation, a feedback-input coupled to a first terminal of the secondary-winding, and a gate-drive-output. A high-voltage startup circuit powers the low-voltage circuit during startup. Periphery circuitry includes a transient voltage suppression diode having an anode coupled to supply power to the high-voltage startup circuit and a cathode coupled to the power-input, a diode having an anode coupled to the first terminal of the secondary-winding and a cathode coupled to the supply-input of the low-voltage circuit. A capacitor is coupled between the supply-input and ground. A transistor has a drain coupled to a second terminal of the primary-winding and a gate coupled to the gate-drive-output.