This paper presents a 6-V to 24-V input range buck converter with a novel constant-charge pulse frequency modulation (CC-PFM) control. Despite the wide input voltage range, current pulses with constant charge are injected into the output capacitor, resulting in an almost constant output voltage ripple. The proposed CC-PFM control has been verified in a prototype buck converter implemented in a 180-nm BCD process, which provides an output voltage of 3.3-V and a load current capability of 100-mA with 92% peak efficiency. Experimental results show that the peak-to peak-to-peak output voltage ripple amplitude only varies by 9-mV over the whole input voltage range. The overall die area is 1.78-mm2, whereas the CC-PFM control section occupies only 0.04-mm2.
