The vast influx of miniature electronic devices and circuitry utilizing low-powered architecture has dominated the market especially in the field of remotely-deployed unattended mobile communication devices and wireless sensor network. To cater for this predicament of providing perpetual power supply, a renewable energy technology needs to be developed. Sound, being the most abundance energy in the environment is the likely candidate to fill this slot. Past researches of acoustic energy harvesting utilized standard full bridge rectifier and active rectification technique to convert the sound energy into
usable electrical energy. However, these rectification techniques together with its derivative such as self-powered circuitry technique suffer some drawbacks in terms of requires the inclusion of battery to operate the circuit. The inclusion of power supply into the active circuit was to solve the problem of low voltage unable to exceed the diode threshold voltage in the standard full bridge rectifier circuit. In this study, the development of passive multiplier circuit for multiplication and rectification purposes operated in low voltage condition has been proposed. The passive multiplier circuit comprises of a step-up
transformer and voltage multiplier-rectifier circuit was designed to multiply and rectify the low voltage acoustic energy harvesting utilizing piezoelectric harvester. The proposed circuit is extremely useful in solving the limitation of low output voltage level from the PZT-5A harvester where, the output is Jess than the forward voltage of dode. The method of rectification utilizes the voltage doubler and tripler circuit together with the step up transformer. The outcome of this research has taken the voltage of 128 mVp into 1.461 Vctc using doubler and 1.874 Vctc using tripler. All these were accomplished using a truly passive rectification technique free of power supply.
