The linear frame saw-tooth is applied to appropriate circuitry from which a corresponding parabolic waveforms is obtained. This waveform is then fed to a comparator together with the linear line sawtooth for comparison. Comparator's output drives the output power stage which is capable of sinking the external coil currents of up to 0.5A. An internal recovery diode feeds back to the power supply the coil fly-back current pulses of as high as 0.5A.