A compact and reliable pulse generator using dual 555-timer IC to produce PWM method

Abstract

One of distinguished nonthermal methods in food processing is the pulsed electric field (PEF) and typically be made up of a pulse generator, high-voltage supply, treatment chamber and control system. To enhance the inactivation rate of microorganisms, pulse generator supposed to deliver an accurate and steady pulse signal. Due to this demand, the idea to innovate an existing pulse generator is significant to be conducted. Thus, this paper proposes a technique to generate an accurate and steady square pulse signal using a combination of two units 555-timer IC. The objective of using dual IC is to obtain a pulse width modulation (PWM) method, which its duty cycle and frequency can be altered independently. The simulation result shows parallel comprehension with the objective, where the duty cycle is successfully adjusted from 10% to 90% of full cycle without affecting its frequency. The alteration is achieved by tuning the value of the variable resistor. In addition, the frequency is varied at selected value ranging from Hz to MHz, just to show that 555-timer IC can provide various frequency levels. The frequency can be determined by choosing the right value of the resistor and capacitor in the circuitry system. Therefore, this pulse generator can be executed to drive switching device such as MOSFET and IGBT to produce an accurate and steady high-voltage pulses which give rise to high intensity pulse electric field, thus kill the bacteria effectively.