To smoothly generate a ramp signal with low power consumption.

A smoothing circuit 12 which smoothes a voltage Vout and outputs a voltage Vrp is arranged behind a ramp signal generating circuit 10 which generates a voltage Vout rising or falling in steps according to a clock signal Clk. The smoothing circuit 12 is a sort of voltage amplifying circuit and its slew rate (response speed) is set an average variation rate of the voltage Vout. Consequently, even when the frequency of the clock signal Clk is low, the voltage Vrp which smoothly varies can be obtained.

COPYRIGHT: (C)2008,JPO&INPIT