ESBT® Power Switch in High Efficiency DC-DC Converter

Well established in low-voltage low- medium- power applications for their high efficiency, DC-DC converters are also widely used in high-voltage high-power Telecom and Industrial applications which are always demanding for higher and higher efficiency. 1200 V State-of-the-Art IGBTs are the best choice in the field of high Current and Three-phase DC-DC converter working at a switching frequency up to about 20 kHz, while 1200 V MOSFETs are definitely the only solution for higher frequency. The trade-off between Conduction Voltage Drop/Losses and switching speed/losses and costs as well helps to make the choice. Recently available in the market, ESBT (Emitter Switched Bipolar Transistor) having high breakdown voltage, low conduction drop and high frequency switching capability, represents the only solution to increase the efficiency and/or reduce the equipment size showing a competitive cost at the same time. A very effective and easy ESBT driving method (ST patent pending) has been fully investigated and tested in a 1.5 kW double switch forward converter. Finally the potentiality of the new device together with the proposed driving solution has been explored in a 12 kW converter.