High voltage BLDC motor driver ICs eliminate heatsink

Featuring high- and low-side fast recovery diode field effect transistors (FREDFETs), for conversion efficiency, the BridgeSwitch is available from Power Integrations.

The integrated half-bridge (IHB) motor driver ICs’ FREDFETs have lossless current sensing, for inverter conversion efficiency of up to 98.5 per cent in brushless DC (BLDC) motor drive applications to 300W. The driver’s distributed thermal footprint eliminates the need for a heatsink, reducing both system cost and weight. Other characteristics are bus voltage sensing and system-level thermal sensing, for refrigerator compressors, HVAC system fans and other residential and light commercial pumps, fans and blowers.

The 600V FREDFETs used in BridgeSwitch ICs incorporate fast, ultra-soft-recovery body diodes. This reduces losses during switching and reduces noise generation, which simplifies system level EMC. The high-voltage, self-powered, half-bridge motor driver ICs have built-in device protection and system monitoring and a robust single-wire status update interface for communication between the motor-microcontroller and up to three BridgeSwitch devices. Each BridgeSwitch device may be configured with different high- and low-side current limits, so there is no need for the microcontroller and external circuitry to protect the system from open or shorted motor windings. Integrated loss-less current monitoring provides hardware-based motor fault protection to satisfy IEC60335-1 and IEC60730-1 requirements.

Other features include up to 20kHz pulse width modulation (PWM) frequency, and a small signal output that provides real-time reporting of FREDFET drain current which mirrors the positive motor winding current. Safety features include two-level device over-temperature detection, low-side and high-side cycle-by-cycle current limit, as well as DC bus over-voltage and under-voltage protection and reporting.

The BridgeSwitch services are compatible with all common control algorithms i.e. field oriented control (FOC), sinusoidal, and trapezoidal modes with sensor and sensorless detection. These are described in three reference designs, also released by Power Integrations, the DER-654, DER-653 and DER-749.

BridgeSwitch is available in InSOP-24C – a small surface-mount package offering creepage distances greater than 3.2 mm and enabling PCB heatsinking via two exposed pads.

Samples of BridgeSwitch ICs are available now.

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