Abstract: A power factor corrector with regulation circuitry. The power factor corrector includes converter circuitry and controller circuitry coupled to the converter circuitry. A switch of the converter circuitry is configured to deliver a signal to the controller circuitry to induce a voltage at an input of the controller circuitry to control conductive state of the switch and at a magnitude that is a function of an input voltage of the converter circuity.

Abstract: A light emitting unit driving circuit may include: an operating voltage supplying unit configured to supply a voltage input for the driving circuit; a driving unit coupled to the operating voltage supplying unit and configured to drive the light emitting unit to make the light emitting unit turn on or turn off; and a feedback control unit coupled between the driving unit and the light emitting unit, and configured to form a feedback loop together with the driving circuit and the light emitting unit to stabilize an operating current of the light emitting unit.

Abstract: A light emitting unit driving circuit may include: an operating voltage supplying unit configured to supply a voltage input for the driving circuit; a driving unit coupled to the operating voltage supplying unit and configured to drive the light emitting unit to make the light emitting unit turn on or turn off; and a feedback control unit coupled between the driving unit and the light emitting unit, and configured to form a feedback loop together with the driving circuit and the light emitting unit to stabilize an operating current of the light emitting unit.

Abstract: An electronic product having a double-PCB sandwich structure includes a PCB assembly, and a casing having an open side. The electronic product is configured such that a protuberance is respectively formed on the inner sides of two side walls of the casing in the longitudinal direction, the PCB assembly comprises an electronic component, a base PCB and a main PCB, the length of the base PCB and the length of the main PCB in the longitudinal direction of the casing are substantially equal to each other and slightly smaller than the length of the casing so that the PCB assembly can be installed into the casing by mating with the protuberances.