Backlight control circuit with under current detection and start-up control

The present invention discloses a backlight control circuit, comprising: a voltage supply circuit for receiving an input voltage and generating an output voltage under control by a control signal; at least one voltage comparison path respectively coupled to at least one light emission device path; a voltage operative amplifier circuit for generating the control signal according to a lowest voltage on the at least one voltage comparison path; and at least one under current detection circuit for detecting whether a corresponding one of the at least one light emission device path is in an under current status, whereby when anyone of the under current detection circuits detects the under current status, it sends an exclusion signal excluding a corresponding one of the at least one voltage comparison path from being an effective input of the voltage operative amplifier.