A switch mode power supply includes a bootstrap circuit, control circuits, and an auxiliary winding coupled to the bootstrap circuit and configured to supply power to the control circuits after startup of the power supply. The bootstrap circuit is configured to supply power to the control circuits during startup and includes an isolation circuit to limit current flow between the starting capacitor and the control circuits while the starting capacitor is charged to a starting voltage by the high voltage input. During the initial charge of the starting capacitor, the control circuits do not have power to provide the initial functionality of the power supply. Once the starting capacitor is charged to the starting voltage, the isolation circuit is activated to allow current flow that powers the control circuits during the remainder of the startup until the auxiliary winding is able to power the control circuits.

The power supply apparatus including a high-voltage generation unit generating a DC voltage VA includes a Zener diode that drops the DC voltage VA to a DC voltage VB, a resistor connected to a line to which the DC voltage VA is output, and a voltage divider that generates a DC voltage VC by dividing the DC voltage VA with the resistor, and the voltage divider adjusts the DC voltage VC such that the potential difference between the DC voltage VB and the DC voltage VC is within a predetermined range.

A DC-to-DC converter includes a first capacitor, first to fourth switches connected in series between first and second electrodes of the first capacitor, a second capacitor connected to a connection node of the first switch and the second switch and a connection node of the third switch and the fourth switch, an inductor connected to a connection node of the second switch and the third switch, and a controller that performs PWM control. In a case where a failure occurs in the second capacitor, the DC-to-DC converter performs PWM control such that the first switch and the second switch enter the same state and the third switch and the fourth switch enter the same state on the basis of a result of comparison between a first detection voltage that is a measured output voltage and a target output voltage of the DC-to-DC converter.

A DC-to-DC converter includes a first capacitor, first to fourth switches connected in series between first and second electrodes of the first capacitor, a second capacitor connected to a connection node of the first switch and the second switch and a connection node of the third switch and the fourth switch, an inductor connected to a connection node of the second switch and the third switch, and a controller that performs PWM control. In a case where a failure occurs in the second capacitor, the DC-to-DC converter performs PWM control such that the first switch and the second switch enter the same state and the third switch and the fourth switch enter the same state on the basis of a result of comparison between a first detection voltage that is a measured output voltage and a target output voltage of the DC-to-DC converter.

Disclosed herein is a AC direct LED driving apparatus. The light emitting diode (LED) driving apparatus includes: a rectifier configured to receive and rectify an alternating current (AC) voltage; an LED configured to emit light based on a rectified voltage received from the rectifier; a capacitor connected to a first terminal of the LED, and configured to drive the LED while alternating between charging and discharging sections according to a preset cycle; a first current driver connected to a second terminal of the LED and configured to control a path of current flowing in the LED and the capacitor based on different input voltage levels; a second current driver configured to control charging and discharging of the capacitor; and a first diode connected onto a current path of the capacitor and the second current driver, and configured to form a discharging path for driving the LED based on a charged voltage of the capacitor.

A voltage converter circuit includes a capacitor having a first end selectively connected to an input power source through a first input switch and a second end selectively connected to the input power source through a second input switch, and a single inductor configured to generate an output voltage in response to a voltage of a node between the single inductor and the first input switch, selectively connect the input power source through the first input switch at the node, and connect the first end of the capacitor at the node.

A voltage converter circuit includes a capacitor having a first end selectively connected to an input power source through a first input switch and a second end selectively connected to the input power source through a second input switch, and a single inductor configured to generate an output voltage in response to a voltage of a node between the single inductor and the first input switch, selectively connect the input power source through the first input switch at the node, and connect the first end of the capacitor at the node.

A switching converter includes a controller configured or programmed to detect voltages of snubber capacitors, a voltage of a first capacitor, and a voltage of a second capacitor using voltage sensors. The controller adjusts the turn-off timings of switches based on the voltages of the snubber capacitors, the voltage between terminals of the first capacitor, and the voltage of the second capacitor.

Systems, apparatuses, and methods are described for power conversion. In some examples, the power conversion may be done by an inverter configured to convert a direct current (DC) input to an alternating current (AC) output. The inverter may include a plurality of capacitors connected at the input of a DC/AC module. The system may include a housing configured to house the inverter. Voltage control circuitry may be configured to increase a voltage at the input of the DC/AC module inside the housing of the inverter.

A wireless power feeder includes a rotatable body and a non-rotatable body including a first surface and a second surface, respectively, that face each other at a predetermined distance, and a power receiving board and a power feeding board on the first surface and the second surface, respectively. The power receiving board includes a pair of first electrodes each including alternating first interconnect patterns and first slits in respective first regions bent at the first slits to form first corrugated parts where a distance from the first surface alternately increases and decreases. The power feeding board includes a pair of second electrodes each including alternating second interconnect patterns and second slits in respective second regions bent at the second slits to form second corrugated parts where a distance from the second surface alternately increases and decreases. The first and second corrugated parts face each other.