A method and apparatus are disclosed for controlling a buck converter. In one aspect, an integrator is coupled to receive a current sense signal representative of a current in a switch of the buck converter and to integrate the current sense signal to produce a first input signal. A ramp generator is coupled to receive an oscillating signal having a same switching period as the switch, and to generate a piecewise linear ramp signal in response to the oscillating signal. The piecewise linear ramp signal has a delay segment of substantially zero slope followed by a plurality of segments having finite linear slopes within the switching period of the switch. A multiplier multiplies the piecewise linear ramp signal to produce a second input signal and a drive signal generator is coupled to receive a third input signal generated in response to the first and the second input signals to produce a drive signal to be coupled to control the switch to substantially regulate an output voltage of the buck converter