Diodes Inc. AM4964 is a single-phase Brushless Direct Current (BLDC) full wave motor driver with combined PWM and temperature speed control functions. By allowing the speed of fans, blowers and extractors to be simultaneously controlled by both PWM and thermistor input signals, AM4964 helps develop more responsive cooling systems for PCs, servers, and industrial instrumentation. The motor speed varies between low and high temperature set-points in response to the ambient temperature and the PWM input signal. Three external resistors allow the low and high temperature set-points, as well as the maximum PWM output, to be easily adjusted. AM4964 also offers a tachometer output, a bias output for a differential unbuffered Hall sensor. and dedicated inputs for 3- or 4-pin Hall sensors for rotor position detection. Available in the TSSOP-20EP package, AM4964 is a highly integrated device that includes a built-in oscillator to eliminate the need for an external capacitor, a minimum speed-setting circuit, and adjustable alpha slope technology to support different speed curve requirements. To protect the motor coil, the driver incorporates thermal shutdown, rotor lock detection, and auto-restart functions.