A voltage conversion system for an electronic timepiece having a power source, which system generates power at lower voltage level than that of the power source for operating at least one of a frequency standard, a frequency converter, a time counter circuit and a display system. The voltage conversion system comprises an oscillator circuit coupled to the power source to generate output signals, a plurality of capacitors, and a plurality of switching elements responsive to the output signals for alternately setting the capacitors in a parallel connected condition and a series connected condition, whereby an output voltage lower than that of the power source is generated at an output terminal of the system.