Fully Integrated Closed-Loop Active Gate Driver IC With Real-Time Control of Gate Current Change Timing by Gate Current Sensing

In order to provide a low-cost closed-loop active gate driver (AGD) that is applicable to both 3-pin and 4-pin power devices, a fully integrated closed-loop gate current sensing (GCS) AGD IC for IGBTs is proposed that controls the timing of gate current changes in real time. In an active gate driving where the gate current is changed three times from large to small to large at turn-on, GCS AGD has the function of changing the time of the first and second slots in real time by detecting the change in gate current using two comparators. Double pulse test measurements of IGBTs are performed at 600 V and under nine combinations of conditions including load current of 20 A, 50 A and 80 A, and temperature of 25 °C, 75 °C and 125 °C, using GCS AGD IC fabricated with 180 nm BCD process. The results show that the proposed GCS AGD reduces the switching loss (E<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LOSS</inf>) and the collector current overshoot (I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OVERSHOOT</inf>) in all nine conditions compared to the conventional single-step gate driving. Specifically, in the nine conditions, with the same I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OVERSHOOT</inf>, the E<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LOSS</inf> is reduced by 16% to 30%, and without increasing E<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LOSS</inf>, the reduction in I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OVERSHOOT</inf> range from 14% to 21%.