Low power biomedical implants usually harvest energy from a small inductor coil or optical energy sources. Those sources can supply very limited amount of energy to the target system because of poor power transfer efficiency and size limitation. Thus, we have to supply as much as energy directly to the load, without wasting energy from auxiliary devices from electrical driving. To save the energy dissipated as heat, when the power supply voltage is excessively large compared to the voltage at the load, we can choose a class-H amplifier-like strategy, where supply voltage tracks the voltage waveform at the load. Among many power conversion topologies that can modulate the supply voltage, the SMPS (Switching Mode Power Supply) is the most promising one; because reverse energy recovery can be used by taking back the charge accumulated on the load capacitor. The CCM buck converter, shown in Figure 1, can possibly work as a voltage tracking power supply modulator. However, we must employ a complicated auxiliary circuit components, such as the Type-III compensator, which greatly hampers its application for biomedical implant applications due to several external passive components.