Automotive-power-switch IC is no dummy
By Bill Schweber -- EDN, October 2, 2003
The IR331X family of automotive-power-switch ICs from International Rectifier performs intelligent high-side power switching in nominal 12V auto applications (Picture). It not only sets current flow on or off based on your control input, but also provides a small amount of current feedback to the control circuitry with ±5% accuracy so that you can assess the load situation, such as an open bulb filament. In the common PWM-drive-controlled situations, this sensing feedback lets the microcontroller control the load current if necessary.
The power switches handle 30, 60, or 100A, depending on model, with current-sense ratios of 2600:1, 5300:1, or 8800:1, respectively. Maximum on-resistance is less than 22 mΩ for the 100A model and substantially less for the other devices. All models incorporate overtem-perature, programmable-overcurrent, and reverse-polarity shutdown protection and are available in TO-220, D2PAK, and TO-262 packages. Prices range from $1.40 and $2.10 (10,000).
International Rectifier Corp, www.irf.com.
