Active Gate Drive Circuit
Publication Date: 2016-Jul-20
The IP.com Prior Art Database
Joonas Puukko: AUTHOR [+2]
IEEE Vol.39, No.3: OTHER [+2]
Page 01 of 4
1Field of invention
Active semiconductor gate drive circuit with controllable du/dt and/or di/dt switching transient without external gate resistors.
2Problem to be solved
To control the conducted and radiated electromagnetic interference (EMI) of semiconductor devices.
3Prior art solutions
Switching speeds and frequencies of modern semiconductors reach levels where e.g. electromagnetic interference (EMI) can prevent from fully utilizing the potential of these devices. An example of these technologies is wide band gap (WBG) semiconductors such as gallium nitride or silicon carbide. Being able to control the du/dt and/or di/dt of the switching transition would allow the designer to optimize the system in terms of losses, EMI and overall cost.
EMI in general can be handled by either reducing the emitted noise or by filtering the generated noise. Common-mode noise origins from the du/dt of the switching transition and the parasitic capacitances between the power circuit and the ground potential. Differential-mode noise, in turn, origins from the di/dt of the switching transition.
Usually there is a strong positive correlation between EMI and operating power, the higher the power the higher the emissions. In many applications it would be desirable to optimize partial load efficiency of the system. An example of these would be photovoltaic and traction applications. In order to keep the EMI below the limits, the du/dt and di/dt could be inversely proportional to the power level, i.e. the lower the operating power the higher the du/dt and di/dt and thus the lower the switching losses and the higher the efficiency. Achieving this with passive gate drive circuits could become extremely complicated. Furthermore, having an active gate drive circuit that would have controllable du/dt and/or di/dt without changing any external components would bring a degree-of-freedom when different applications or the life cycle (= changing standards and requirements) of the product is considered.
Present state-of-the-art in driving semiconductors can be summarized as:
External gate resistor with a driver IC or current buffer as in Fig 1.
Independent turn-on and turn-off transitions. The solution may only have one branch, i.e. one gate resistor for turn-on and one for turn-off or several as in Fig. 2.
Integration of the current buffer to the semiconductor package as in Fig. 3. Current buffer transist...