This superior efficiency, combined with the distributed thermal footprint provided by the IHB controller, eliminates the need for a heatsink, reducing system cost and weight. Integrated lossless current sensing, bus voltage sensing, and system-level thermal sensing make this family of devices ideal for BLDC motors in household appliance applications. BridgeSwitch devices target refrigerator compressors, HVAC system fans, and other light residential and commercial pumps, fans, and blowers.
The 600 V FREDFETs used in the BridgeSwitch integrated circuits incorporate ultra-smooth fast recovery diodes. This dramatically reduces switching losses and noise generation, simplifying the system's EMC level. The new medium- and high-voltage motor driver integrated circuits also feature built-in device protection and system monitoring, along with a single-wire status update interface that enables communication between the motor microcontroller and up to three BridgeSwitch devices. Each BridgeSwitch device can be configured with different HS and LS current limits, eliminating the need for the microcontroller and external circuitry to protect the system from open or shorted motor windings. The integrated lossless current monitoring provides hardware-based motor fault protection, simplifying the task of providing protection under motor fault conditions to meet IEC60335-1 and IEC60730-1 requirements.
Senior Product Marketing Manager Cristian Ionescu-Catrina commented, “We have re-analyzed the challenges posed by the growing BLDC market and increasingly stringent energy regulations worldwide, and have produced an innovative solution that saves energy and space while reducing the bill of materials. This facilitates compliance with safety standards, simplifies circuitry, and reduces development time.”
Other features include a PWM frequency of up to 20 kHz and a small signal output that provides accurate, real-time reports of FREDFET drain current, reflecting the positive current of the motor winding. Safety features include two-level device overheat detection, HS and LS cycle-by-cycle current limiting, and DC bus overvoltage and surge protection and notification. The devices are compatible with all common control algorithms: field-oriented control (FOC), sinusoidal, and trapezoidal modes with and without sensor detection, as described in the reference designs DER-654, DER-653, and DER-749. BridgeSwitch is available in an InSOP-24C, a small surface-mount package that offers creepage distances greater than 3.2 mm and allows for PCB heatsink placement via two visible pads.
