Patent ID: 8519635

Claim:
A light-emitting device electrically connected to an external variable voltage source, the light-emitting device comprising: a plurality of light-emitting modules sequentially electrically connected in series and electrically connected to the external variable voltage source, wherein: each of the light-emitting modules has at least one light-emitting unit, a first connection terminal and a second connection terminal; at least one of the light-emitting modules has a bypass unit and a control unit; the bypass unit is electrically connected to the light-emitting unit; the second connection terminal of the light-emitting module having the bypass unit and the control unit is electrically connected to the first connection terminal of the other light-emitting module and serves as a detection terminal; and the control unit detects a voltage of the detection terminal and accordingly controls the bypass unit and adjusts a current flowing through the light-emitting unit.