Development of External Defibrillator with Energy Discharge System Using IGBT Based H-Bridge

An external defibrillator with biphasic and monophasic modes was designed with a microcontroller-controlled H-Bridge Insulated Gate Bipolar Transistor (IGBT) circuit. The IGBT-based H-Bridge enables a discharging time of no more than 20ms, meeting industry standards (Nihon Kohden). Maximum energy that can be accepted by human body is 360J depending on age and weight. To meet these energy needs, a high voltage converter is needed. A 12V DC voltage is converted to 2000V using switching transformer method. Furthermore, the target of charging time is no more than 6 seconds. The high voltage conversion result is used to charge 10 capacitors arranged in series-parallel with capacitance value of 250μF / 2200V. The capacitors are used to temporarily store energy before being given to the fibrillation patient. Based on experiment results, the external defibrillator was able to produce a maximum energy of 500J (adjustable), exceeding the 360J standard. The switching transformer method achieved a maximum voltage of 2000V. In addition, the external defibrillator has charging and discharging times of less than 6 seconds and 20ms, respectively. The results show that the external defibrillator has met the requirements for defibrillation procedures while demonstrating its capability for enhanced energy output.