EL SEGUNDO, CA. October 2000 - International Rectifier (NYSE: IRF) introduced the new IR2172 linear current-sensing IC with built-in over-current shutdown for motor drive applications. The IR2172 eliminates external current sensing protection circuits. The new IC is rated at 600V, for 230V three-phase AC inverter or brushless DC industrial motor drives used in conveyor belts and similar applications.

The IR2172 has a 1.5 microsecond over-current shutdown feature with a wired-OR connection capability directly to the microprocessor or DSP. Conventional linear current-sensing opto- or Hall effect-based systems have typical shutdown times of three to four microseconds. Motor drive circuits using opto or Hall effect sensors require two external comparators and a level-shift operational amplifier to achieve the same function as the IR2172.

According to David Tam, Vice President for power integrated circuit products at IR, "The new IR2172 significantly simplifies motor drive design in three ways. First, the IR2172 eliminates bulky and slow opto- or Hall effect couplers. Also, as opto-couplers age, the current transfer ratio (CTR) between the LED and receiving device degrades, causing system failure. The IR2172 does not degrade over time, increasing reliability. Second, the direct connection between the IR2172 and the Motor Control microprocessor or DSP simplifies over-current protection circuits. And third, the new device uses PWM output and runs off a bootstrap supply instead of a dedicated secondary supply to significantly reduce size requirements, parts count and system cost. The IR2172 is another example of IR's industry-leading high-voltage power IC products technology."

The new motor driver comes in two industry-standard, compact package outlines: SO-8 and 8-pin DIP. The monolithic high-voltage IC construction eliminates optical or mechanical links between the current sensors and motor drive output circuits, and increases reliability while shrinking circuit size as much as 75%, compared to circuits using Hall-effect or opto-based couplers.

Motor Drive Circuit with Hall Effect Sensor

Typical three-phase motor drive circuits using Hall effect sensors tend to be complex, bulky and expensive.

Simplified Circuit Using IR2172 Current-Sensing ICs

Three phase motor drive circuits using the IR2172 eliminate external opto- or Hall-effect sensors, reducing circuit size, simplifying design and increasing reliability. The IR2133 is a three-phase bridge driver IC. Check the IR Web site for more information on the IR2133.

Pricing and Additional Information

Pricing for the new IR2172 begins at US $3.55 each in 10,000-unit quantities. The IR2172 comes in either an 8-pin DIP or SO-8 package.