UCC2626

UCC2626, UCC3626 SLUS318B – APRIL 1999 – REVISED JANUARY 2002 BRUSHLESS DC MOTOR CONTROLLER FEATURES D Two-Quadrant and Four-Quadrant Operation D Integrated Absolute Value Current Amplifier D Pulse-by-Pulse and Average Current Sensing D Accurate, Variable Duty-Cycle Tachometer Output D Trimmed Precision Reference D Precision Oscillator D Direction Output DESCRIPTION The UCC3626 motor controller device combines many of the functions required to design a high-performance, two- or four-quadrant, threephase, brushless dc motor controller into one package. Rotor position inputs are decoded to provide six outputs that control an external power stage. A precision triangle oscillator and latched comparator provide PWM motor control in either voltage- or current-mode configurations. The oscillator is easily synchronized to an external master clock source via the SYNCH input. Additionally, a QUAD select input configures the chip to modulate either the low-side switches only, or both upper and lower switches, allowing the user to minimize switching losses in less demanding two-quadrant applications. The device includes a differential current-sense amplifier and absolute-value circuit which provide an accurate reconstruction of motor current, useful for pulse-by-pulse overcurrent protection, as well as closing a current control loop. A precision tachometer is also provided for implementing closed-loop speed control. The TACH_OUT signal is a variable duty-cycle, frequency output, which...