A ramp signal generation circuit is disclosed. The ramp signal generation circuit comprises a ramp signal generator, a buffer, a comparator, and a switching circuit. The switching circuit provides current to an output of the ramp signal generation circuit in response to a control signal output by the comparator. When a high slew rate is required, the output of the ramp signal generation circuit is driven by the current provided by the switching circuit. Otherwise, the output of the ramp signal generation circuit is driven by an output of the buffer.