Patent ID: 9544959
Date: 2017-01-10
CPC Classifications: F21K,F21V,F21Y,H02M,H05B,Y02B

Claim:
1. A light-emitting diode (LED) lamp, comprising: a plurality of LED printed circuit boards (LED PCBs); a light emission portion comprising LED arrays disposed on the plurality of LED PCBs; a lamp base portion connected to the light emission portion, the lamp base portion comprising electrical connection terminals; a bridge rectifier connected to the electrical connection terminals, the bridge rectifier configured to convert an alternating-current (AC) input voltage into a direct-current (DC) voltage; and an LED driving circuit coupled to receive the DC voltage from the bridge rectifier, the LED driving circuit comprising an input filter, a power factor correction (PFC) and control device, a switch controlled by the PFC and control device, a current sensing resistor, a diode, an inductor with its current charging and discharging controlled by the switch, a resistor, an output capacitor in parallel with the resistor and connected to the inductor to build up an output voltage and to power the LED arrays, and a voltage feedback module configured to draw a partial power from the output voltage to sustain an operation of the PFC and control device, wherein, responsive to detecting a zero current in the inductor within an AC cycle of the AC input voltage, the PFC and control device generates a zero current detection signal to turn the switch on and off with a constant on-time and a varied off-time.