Patent ID: 8446103

Claim:
A lamp driver, comprising: a power supplying part configured to switch an input power, supply a driving power to at least one lamp, and control brightness of the at least one lamp according to a dimming signal; a signal supplying part configured to output a first comparison result signal obtained by comparing i) a current sensing signal obtained by sensing a current flowing through the at least one lamp with ii) a reference signal having a current level set in advance when the dimming signal is a logic high signal, and output a second comparison result signal having a voltage level set in advance when the dimming signal is a logic low signal; and a controlling part configured to control the switching of the power supplying part based on an output signal of the signal supplying part, wherein the signal supplying part comprises: a switch electrically connected between a current sensing signal input terminal, to which the current sensing signal is inputted, and a reference signal input terminal, to which the reference signal is inputted, wherein the switch is switched off when the dimming signal is the logic high signal so that the current sensing signal input terminal and the reference signal input terminal are electrically disconnected from each other, and the switch is switched on when the dimming signal is the logic low signal so that the current sensing signal input terminal and the reference signal input terminal are electrically connected to each other to supply the reference signal to the current sensing signal input terminal; and a comparator configured to output either the first comparison result signal or the second comparison result signal by comparing a signal inputted from the current sensing signal input terminal with the reference signal.