Ground fault detector IC for complete short circuit protection in motor drive applications

摘要

An integrated fault detector for motor drive application in Bi-CMOS high voltage technology is presented. The goal of the IC is the detection of different types of faults which can affect a three-phase inverter for motor drive. The fault is detected sensing a shunt resistor put on the DC+ bus of the inverter and communicated to either a DSP or a gate driver using an open drain output pin. The proposed IC represents an integrated and inexpensive solution, has a very simple structure and can be used in application with the inverter DC+ bus up to 600V. The circuit does not need any external supply and exploits the possibility to easily regulate the voltage threshold for the over-current detection. The circuit is detailed and explained. Measurements on the implemented IC are reported. An applicative test interfacing the IC with a gate driver has been done and results are shown.