EL SEGUNDO, CA, November 2000 - International Rectifier (NYSE: IRF) has created a unique motor drive power management architecture called Accelerator^TM. The new architecture is positioned between the micro- or DSP-controller and the motor (see Figure 1), to enhance and simplify DSP and microprocessor-controlled Motor Control circuits. By simplifying motor drive power management, more design effort can be concentrated on the main control algorithm and man-machine interface.

Figure 1. IR's breakthrough Accelerator^TM architecture uses a unique blend of technologies to simplify and enhance motor drive power management.

The new Accelerator chip set architecture consists of mixed signal 0.5µm CMOS and high voltage ICs with ratings from 600 to 1200V. The Accelerator architecture can be applied to AC induction motors, as well as brushless DC motors. Typical applications include industrial AC drives, industrial servo drives, compressor drives, washing machines, electric power steering, integrated starter alternators and high reliability drives.

The new IR architecture simplifies power management design and increases reliability by reducing total parts count by 25%, and cutting circuit board footprint by 50%. Motor drives using this architecture can easily fit within the dimensions of the industry-standard ECONO2 package outline, approximately 4.25 x 1.75 x 0.62 in. (L x W x H).

According to David Tam, Vice President for power integrated circuit products at IR, "The new Accelerator architecture delivers speed range ten times wider than conventional designs, with significantly improved low speed operation for AC inverter motor drives by optimizing dead time. System performance is enhanced because the temperature-compensated current measurement technique enables torque precision as high as plus/minus one percent, versus plus/minus two to three percent in existing motor drives."

The chip set integrates analog and interface functions and features a dual port memory with serial interface I/O. It includes versatile diagnostic functions, dead time generation and dead time compensation functions. The chip set can be programmed by a user-defined PWM or a built-in, optional space vector PWM generator.

IR's high voltage ICs are rated at 600V for 230VAC drive circuits, and 1200V for 460VAC drive circuits. The gate drivers are designed with matched delays to enable very small dead time. Optimized dead time compensation, based on voltage sensing, delivers a ten times more useable speed range. Current sensing delivers one percent accuracy for better torque precision. Robust protection against ground fault and line-to-line short circuits ensures high system reliability. IR MOSFETs and IGBTs in industry-standard or application-specific packages work seamlessly with the analog portion of Motor Control circuits.