The pursuit of the highest efficiency is the key demand of today’s power electronic products. Recently, Infineon Technology Co., Ltd. (FSE: IFX / otcqx: ifnny) launched the latest isolated eicedriver ™ 2l-src compact (1ed32xx) gate driver series. The series adopts 8 mm wide body package to ensure simple design, and integrates two-stage swing rate control to significantly improve system efficiency. With high voltage and high safety, the series is suitable for applications with severe isolation requirements, such as 1700V industrial motor drive. In addition, it is ideal for applications such as solar systems, uninterruptible power supplies and electric vehicle charging.
The 1ed32xx series optimizes the gate driver circuit. It can reduce the DV / dt and EMI during start-up and light load operation, at the same time, reduce the switching loss during high load operation to the greatest extent. It can dynamically adjust the yaw rate during operation, so as to optimize the system output power without changing the BOM and affecting the EMI behavior.
The gate driver family provides drive currents of 10 A and 18 a. It has a miller clamp, which is very suitable for the use of 0 V off power switch to avoid parasitic conduction; At the same time, its rated voltage is up to 2300 V, supporting power switch with blocking voltage far exceeding 1200 v. In addition, UL 1577 and VDE 0884-11 (enhanced isolation) certification ensure excellent application safety and long service life.
Eicedriver 2l-src compact gate driver series can now be ordered, eval-1ed3241mx12h and eval-1ed3251mx12h evaluation board will also be available soon.
SRC is the acronym of slow rate control, which means voltage conversion rate control.
Both IGBT and MOSFET are devices that often work in the switching state. From on to off, or from off to on, will pass through the linear region, so there will always be switching loss. In order to reduce the switching loss and improve the efficiency, we hope that the shorter the switching process time is, the better, that is, the faster the switching between on and off is. However, if the switching speed is too fast, the larger the DV / DT is, the more serious the problem of EMI is. This phenomenon is more prominent when the current is small and the load is light. So people have to make a trade-off between speed and EMI.
But if it has the function of SRC, DV / dt can be controlled and adjustable within a certain range. For example, the DV / DT is reduced when the load is working at low current, while the DV / DT is increased when the load is working at high current, so as to achieve the purpose of reducing the overall switching loss under the corresponding EMI requirements.
The two IGBTs in the upper and lower bridge structure are always connected alternately. If they are connected at the same time, the bridge arm will have a straight through short circuit, which will cause the explosion. When one of the pipes works in the off state, while the other will produce several kV / US DV / dt due to the opening process. This will make the transistor generate current through CGC capacitor to fill the gate, which may cause the gate voltage to rise and turn on the device. Because CGC is also known as Miller capacitor, we call this turn-on Miller turn-on. The circuit that can discharge the distributed current is called Miller clamp circuit.
This circuit is usually provided by a MOS transistor, as shown in the figure above. The gate of the tube is controlled by the driving signal, and it will turn off when it is normally switched on and off, showing high resistance. It can only turn on when the device is in the off state, playing the role of clamp protection.