栅电荷是用于衡量功率MOSFET开关性能的重要参数,通常采用在栅极输入电流阶跃信号的方法来测量。一种新型的栅电荷测试电路被提出,该测试电路使控制信号从MOSFET的源极输入,从而消除了控制信号对栅极输入电流的影响。因为输入电流太小不能直接测量,测试时采用测量电压阶跃信号的方法来衡量电流阶跃信号的性能。与以往的测试电路对比结果表明,该电路可以使MOSFET栅极输入的电流更接近于理想的电流阶跃信号,该信号上升时间小于100ns,并且上升后稳定,因此提高了栅电荷测量的准确度。
The gate charge is an important parameter of the power MOSFET, which is used to determine its switching performance. Usually, a current pulse is applied to the gate for the measurement. A novel gate charge testing circuit was presented. The influence of the control signal on the gate input current was eliminated because the control signal was input from the source of the MOSFET. The voltage pulse was measured to evaluate the quality of the current pulse, because the input current was too small to be measured directly. Compared with the previous testing circuit, the proposed circuit shows the MOSFET gate input current is closer to the ideal current pulse, the rise time of the current pulse is less than 100 ns and the pulse become stable after rising, which makes the gate charge testing results more accurate.