Patent ID: 8922123

Claim:
A light-emitting device, comprising: a light-emitting module, comprising a plurality of light-emitting unit strings, each of the light-emitting unit strings comprising a plurality of light-emitting units connected in series, wherein an end of each of the light-emitting unit strings receives a same DC voltage; a light adjustment control bus, comprising a plurality of current control units, each being connected in series to at least one of the light-emitting unit strings, so as to control a current of each of the light-emitting unit strings; a control module, configured to retrieve a voltage drop value across each of the current control units, so as to further determine whether the light-emitting units in each of the light-emitting unit strings malfunction; and when the light-emitting units of a specific string among the light-emitting unit strings malfunction, and the number x of malfunctioned light-emitting units is larger than or equal to a malfunction threshold value p, the control module shorts the malfunctioned light-emitting units in the specific string and shorts (x−p+1) light-emitting units in each of the light-emitting unit strings other than the specific string, so as to decrease the DC voltage received by each of the light-emitting unit strings.