Blanking-time-less desaturation protection method for power devices
View Patent ↗The disclosure relates to a devices, systems and methods implementing desaturation protection during faults (over-current or short-circuit faults) for a power device by monitoring drain source voltage and rate of change of the drain source voltage which provides a fault response time (t 0 to t 2 ) that is shorter than the blanking time (t 0 to t 5 ) required by conventional desaturation protection methods.
1 . A circuit that provides blanking-time-less desaturation protection for a power device during a fault, comprising:
a desaturation protection sub-circuit;
a fault monitoring sub-circuit; and
a totem-pole driver sub-circuit,
wherein a drain-source voltage, V ds , and a rate of change of the drain-source voltage, dv/dt, of the power device are monitored during the fault, wherein the fault comprises a short-circuit (SC) fault and the SC fault is first monitored by the fault monitoring circuit at a time, t 2 , by sensing fall in dv/dt of Vds, wherein t 2 is shorter than the blanking time t 5 , and then monitored by the desaturation protection circuit at time t 5 , and wherein once the SC fault is monitored at time t 2 by the fault monitoring circuit, active gate clamping is activated by the totem-pole driver sub-circuit to mitigate a SC current until desaturation protection is triggered at time t 5 , after which the power device is fully turned off,
wherein the circuit provides a fault response time (t 0 to t 2 ) that is shorter than a blanking time (t 0 to t 5 ) required by conventional desaturation protection methods.
2 . The circuit of claim 1 , wherein the fault comprises an over-current (OC) fault and detection of V ds by the desaturation protection sub-circuit is used to monitor the OC fault.
3 . The system of claim 1 , wherein the power device comprises a Si, SiC, or GaN power device.