An integrated fault detector in high voltage technology for motor drive applications

In this paper, an integrated solution of fault detector for motor drive applications is presented. The circuit is developed in monolithic high voltage technology. The goal of the IC is the detection of different types of fault which can affect the three phase inverter or the motor in electrical drive systems. The fault condition is detected sensing a shunt resistor put on the DC+ bus of the inverter and can be communicated to the DSP using an open drain output pin of the chip. The proposed IC represents a versatile and inexpensive solution, requires few external passive elements and can be used in applications with the inverter DC+ bus up to 600 V. The circuit does not need any external supply. It offers the possibility to regulate the voltage threshold for the fault detection using two external resistors and guarantees the response time required by the considered applications. The designed circuit, its characteristics and its performances are reported and discussed.