A power supply receives AC power and generates a DC output voltage. The power supply may be divided into a primary section that converts AC power to a relatively high DC voltage. A secondary section converts this relatively high DC voltage into a well-regulated lower DC voltage. In an embodiment, the current and/or power supplied by the primary to the secondary side is used by the secondary side in a closed-loop feedback system to limit the current drawn by the secondary side to a configurable value.

A power supply receives AC power and generates a DC output voltage. The power supply may be divided into a primary section that converts AC power to a relatively high DC voltage. A secondary section converts this relatively high DC voltage into a well-regulated lower DC voltage. In an embodiment, the current and/or power supplied by the primary to the secondary side is used by the secondary side in a closed-loop feedback system to limit the current drawn by the secondary side to a configurable value.

A power supply may include multiple converters connected in parallel. The power supply may detect a signal that indicates how much power a device uses. Based on the signal, a converter controller may determine which of the multiple converters to activate or deactivate to supply enough power to meet the power load of the device and to operate the highest efficiency possible. The amount of power output from the power supply may be the sum of the power output by each of the converters that is activated. The power supply may use the multiple converters to operate at high efficiency throughout a wide range of power load levels. Such a power supply may achieve a haystack (i.e., near flat) power efficiency curve throughout a large part of its operating range.

A power supply may include multiple converters connected in parallel. The power supply may detect a signal that indicates how much power a device uses. Based on the signal, a converter controller may determine which of the multiple converters to activate or deactivate to supply enough power to meet the power load of the device and to operate the highest efficiency possible. The amount of power output from the power supply may be the sum of the power output by each of the converters that is activated. The power supply may use the multiple converters to operate at high efficiency throughout a wide range of power load levels. Such a power supply may achieve a haystack (i.e., near flat) power efficiency curve throughout a large part of its operating range.

An the LED driving circuit, for driving an the LED load, includes: a bridge rectifier for rectifying an AC input voltage into a DC voltage; a serial capacitor voltage divider coupled to the bridge rectifier, including a plurality of serial capacitors; a half-bridge switch, coupled to the serial capacitor voltage divider; and a controller coupled to the half-bridge switch, for determining whether the DC voltage is higher than a threshold value and for controlling the half-bridge switch in a full-voltage mode or a half-voltage mode. In the full-voltage mode, the plurality of serial capacitors of the serial capacitor voltage divider synchronously supply power to the LED load. In the half-voltage mode, the plurality of serial capacitors of the serial capacitor voltage divider alternatively supply power to the LED load.

A DC filter device includes: a first filter device connection; a second filter device connection; a third filter device connection; a fourth filter device connection; a coil core; at least one first coil arranged on the coil core, the at least one first coil being connected in between the first filter device connection and the third filter device connection; at least one second coil arranged on the coil core, the at least one second coil being connected in between the second filter device connection and the fourth filter device connection; and a third coil arranged on the coil core, the third coil having a first coil connection and a second coil connection. The first coil connection and the second coil connection are connected to one another via a circuit device, which circuit device has a resistor.

A DC filter device includes: a first filter device connection; a second filter device connection; a third filter device connection; a fourth filter device connection; a coil core; at least one first coil arranged on the coil core, the at least one first coil being connected in between the first filter device connection and the third filter device connection; at least one second coil arranged on the coil core, the at least one second coil being connected in between the second filter device connection and the fourth filter device connection; and a third coil arranged on the coil core, the third coil having a first coil connection and a second coil connection. The first coil connection and the second coil connection are connected to one another via a circuit device, which circuit device has a resistor.

Systems for power factor correction are provided. Aspects include a voltage source connected to a first node, wherein the voltage source is configured to provide a first voltage, a sense resistor connected between the first node and a second node, a load connected to the second node, a power factor correction capacitor connected in parallel with the load, and a controlled voltage source configured to provide a second voltage to the power factor correction capacitor based on a control signal, wherein the control signal is received from a power factor correction circuit configured to determine a time difference between a zero-crossing of a voltage signal and a zero-crossing of a current signal from the voltage source.

Systems for power factor correction are provided. Aspects include a voltage source connected to a first node, wherein the voltage source is configured to provide a first voltage, a sense resistor connected between the first node and a second node, a load connected to the second node, a power factor correction capacitor connected in parallel with the load, and a controlled voltage source configured to provide a second voltage to the power factor correction capacitor based on a control signal, wherein the control signal is received from a power factor correction circuit configured to determine a time difference between a zero-crossing of a voltage signal and a zero-crossing of a current signal from the voltage source.

Apparatus providing a regulated power supply to an oscillator comprises a reference voltage generator supplying a voltage reference, a regulator producing, based on a voltage received thereat, a regulated supply used by the oscillator which bases its frequency thereon, a capacitor having a terminal coupled to the regulator at a point, and a switch that is coupled to the reference voltage generator and to the point, wherein the closed switch couples the reference voltage generator to the point and wherein the open switch disconnects the point from the reference voltage generator, the switch being closed for a first time period during which a voltage based on the voltage reference from the reference voltage generator is supplied to the regulator and capacitor, and for a second, subsequent, time period the switch is opened and voltage stored on the capacitor is supplied to the regulator.