Automotive Fan Control with Smart Power Switch [From Mind to Market]

This article presents a fan control unit requiring 30 A motor currents up to 20 kHz PWM. The smart integrated circuit (IC) used here includes a self-protected high-side switch with 4 mOmega RDS_ON, all digital control from a microcontroller, and extended diagnostics. High-current switching at high frequency generates electromagnetic interference (EMI) and power losses. Corner rounding and slew rates were optimized to reduce EMI filter size on the module. The power QFN (PQFN) package, half the size of the equivalent conventional package, helps to evacuate high power dissipation during switching. A smart power switch, combined with a 16-b microcontroller (MCU) and the control area network (CAN) communication protocol, provides an embedded solution, bringing cost savings on the system.