RDK-851: 50W, 270 ~ 365V, 3-Phase BLDC/PMSM Driver

RDK-851 is a 3-phase inverter for brushless DC motor driver applications, employing three BRD1260C devices. The circuit enables driving a high-voltage, 3-phase brushless DC (BLDC) motor from a rectified AC input voltage. The signal control interface allows driving the inverter with various control schemes such as six-step and sinusoidal control. BridgeSwitch integrates two N-channel 600 V rated power FREDFETs, gate drivers and controllers into a low profile surface mount package IC.

The power FREDFETs feature ultra-soft, fast recovery diodes ideally suited for hard switched inverter drives. Both drivers are fully self-supplied eliminating the need for an external power supply for the design. An optional device power supply input allows external bias operation for applications that require a very low inverter no load input power or operate at elevated ambient temperatures.

BridgeSwitch has device internal fault protection and system-level monitoring. Internal fault protection includes cycle-by-cycle current limit for both FREDFETs and two-level thermal overload protection. System level monitoring includes high-voltage DC bus sensing with multi-level under-voltage thresholds and one overvoltage threshold as well as driving external sensors such as a thermistor for system temperature monitoring.

This design example employs a DC bus sensing on one device and provides a system sense input on another device. Half-bridge phase current (low-side FREDFET instantaneous current) information is provided through its instantaneous phase current output IPH pin. A single-wire open-drain bus communicates all detected fault or status change conditions to the system microcontroller. The system sense input, instantaneous phase current output, status communication bus, and the inverter control inputs are available through the board interface connectors.