Solid-state lighting compatible with ballasts and operable with AC mains
AssigneeLightel Technologies, Inc.
InventorChungho Hsia
Life of this patent
Estimating the term…
Abstract
A light-emitting diode (LED)-based solid-state universal lamp using a ballast compatible and AC-mains operable (BA) LED driving circuit with a power factor correction (PFC) and control device operates normally for a regulated power and current from either ballast or AC mains. The BA LED driving circuit is configured to operate in a wide range of input voltages and frequencies, especially for various high voltages and high frequencies associated with various ballasts. With a cycle-by-cycle current control and power switching at a constant on-time and varied off-time, an over-rated surge current is limited, preventing occasional fire hazards occurred in the ballast.
Claims10
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.
Dependencies are inferred from the claim text.