An electronic device includes: a clock booster including a doubler capacitor, the clock booster configured to precharge the doubler capacitor and provide a boosted intermediate voltage greater than an input voltage; a secondary booster including a booster capacitor, the secondary booster configured to use the voltage stored on the doubler capacitor to generate a stage output greater than the boosted intermediate voltage; and a connecting switch connected to the clock booster and the secondary booster, the connecting switch configured to electrically connect the doubler capacitor and the booster capacitor during a direct charging duration for charging the booster capacitor using source-secondary current from an input voltage supply instead of or in addition to the voltage stored on the doubler capacitor.