基于可变消隐时间的SiC MOSFET Uds检测法

Uds Detection Method of SiC MOSFET Based on Variable Blanking Time

漏源电压检测作为一种成熟的检测方法,广泛用于碳化硅金属-氧化物半导体场效应管(SiCM0SFET)短路保护。从兼容性角度考虑,为满足不同工况下的短路保护要求,检测电路内的消隐时间需从大设置,这势必会影响保护速度甚至无法有效保护器件。在此分析了传统漏源电压检测中消隐时间设置的机理,提出一种能随不同工况改变消隐时间的漏源电压检测电路。内置的漏源电压欧姆区检测单元使开通瞬态下的检测消隐时间随工况改变,加快负载故障(FUL)检测速度;栅压检测单元利用栅极电压在短路时的特性加快硬切换故障(HSF)检测速度,达到抑制短路电流、有效保护器件的目的,并通过实验验证了该方法的可行性。

As a mature and commercial short-circuit protection method, drain-source voltage detection is widely used to short-circuit protection of Silicon carbide metal-oxide semiconductor field effect transients (SiC MOSFET). Considering compatibility issues,the blanking time in the detection circuit must be set a large value to meet the protection requirements under different working conditions.The mechanism of the blanking time in the traditional drain-source voltage detection method is analyzed, and a new desaturation detection circuit that can alter the blanking time in different conditions is proposed.The built-in drain-source voltage ohm zone detection unit changes the blanking time of the tum-on transient with the operating condition varying, speeding up (FUL) detection;the gate-voltage detecting unit accelerates the detection of hard switching failure (HSF) through characteristic of the gate voltage in the short circuit. The purpose of suppressing short-circuit current and effectively protecting the device is achieved, and the feasibility of the method is verified by experiments.