Patent ID: 8890439

Claim:
A light-emitting device comprising: a plurality of sequentially connected LED units electrically connected to a first power source with a first power voltage; a switching circuit electrically coupled to the LED units; a second power source configured to provide with a second power voltage at a lower voltage value than the first power voltage, the second power source electrically coupled to the LED units through the switching circuit; a control module in connection with the switching circuit for controlling the switching circuit to selectively switch power delivery from the first power source and the second power source to the light-emitting diode units; wherein when the first power voltage is delivered from the first power source to the LED units, the control module controls the switching circuit to establish serial connection between the LED units, wherein when the second power voltage is delivered from the second power source to the LED units, the control module controls the switching circuit to establish parallel connection between the LED units.