A circuit (100) for produces an LCD contrast voltage signal (VLCD) for a low power MCU-controlled application. The reference voltage (VREF) for a switched mode power supply circuit (210) is supplied by a circuit comprising: logic control circuitry (110) for receiving MCU commands, a counter (120), a digital-to-analog converter (130), and a transmission gates (140, 150) and capacitors (160, 180) for generating the SMPS reference voltage (VREF), and a comparator to set off a recharge cycle whenever the capacitors' voltage difference is more than a pre-set offset voltage. This circuit has lower quiescent power consumption since, in idle cycle, only the comparator (200) consumes quiescent current which can be less than 1 .mu.A.