A pulse width modulated dimming pulse signal PWM is input to a control input terminal P5. A standby terminal P6 receives a standby signal STB that indicates switching between a standby state and an operating state of a current drive circuit 8. A burst dimming terminal BS is provided to each of eight respective channels. Each burst dimming terminal BS receives a voltage at one terminal (cathode) of a corresponding LED string 6. When the voltage level of the standby signal STB is included in a first voltage range, a burst controller 9 is set to an all channel common mode, and when it is included in a second voltage range, the mode is set to a phase shift mode φSHIFT. The burst controller 9 set to the phase shift mode φSHIFT automatically sets the phase shift angle according to the number of connected LED strings 6.