FEATURES

Two-Quadrant and Four-Quadrant Operation

Integrated Absolute Value Current Amplifier

Pulse-by-Pulse and Average Current Sensing

Accurate, Variable Duty-Cycle Tachometer

Output

Trimmed Precision Reference

Precision Oscillator

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 can be used directly for

digital control or filtered to provide an analog

feedback signal. Other features include COAST,

BRAKE, and DIR_IN commands, along with a

direction output, DIR_OUT.