Thermoelectric generator (TEG) is a generator which converts heat energy into electrical energy. Electrical energy needs to be stored before used for power up any electronic device. In order for storing enough of energy, charge pump is needed to step up DC to DC voltage. However the voltage at the storage capacitor saturate at the voltage level which is similar to the voltage that generated by the thermoelectric generator (TEG) which is dependent on the temperature gradient and commonly less than 2 V, therefore PWM input is needed when designing a DC to DC voltage converter. In this paper, the problem facing of TEG which is low voltage is solved by using 4-stage charge pump and astable multivabrator as power conditioning circuit. To determine the most suitable combination of charge pump and multivibrator, three different output frequencies of multivibrator are designed and analyzed the functionality. Besides, three sets different capacitor values of charge pump are tested with Multivibrator to determine the most suitable combination of Multivibrator and Charge pump circuit.