A4934: Three-Phase Sensorless Fan Driver

This device is no longer in production. The device should not be purchased for new design applications. Samples are no longer available. Date of status change: October 31, 2011.

Recommended Substitutions: For existing customer transition, and for new customers or new applications, refer to theA4941.

The A4934 three-phase motor driver incorporates BEMF sensing to eliminate the requirement for Hall sensors in fan applications.

A pulse wave modulated (PWM) input is provided to control motor speed, allowing system cost savings by eliminating external variable power supply. PWM input can also be used as an on/off switch to disable motor operation and place the IC into a low power standby mode.

The A4934 soft switching settings are designed for lower inductance or lower speed motors. For higher inductance or higher speed motors consider using the pin-compatibleA4941.

• Sensorless (no Hall sensors required)
• Soft switching for reduced audible noise
• Minimal external components
• PWM speed input
• FG speed output
• Low power standby mode
• Lock detection
• Optional overcurrent protection