A power supply for a capacitive load, such as an electroluminescent lamp, converts a low battery voltage to a significantly higher voltage of alternating polarity to drive the load. A desired voltage waveform is applied to the load by accumulating charge in its inherent capacitance from voltage spikes resulting from rapidly disconnecting an inductor from the battery. The maximum voltage applied to the load is maintained below a maximum by a feedback loop that monitors a reduced voltage by use of a voltage divider. The voltage divider is formed of a plurality of capacitors connected in series, the reduced voltage being monitored across one of them. The entire power supply is formed on a single integrated circuit chip, except for the inductor, battery and load.