8983

SPINDLE & VOICE-COIL

ACTUATION MANAGER/DRIVER

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

FUNCTIONAL BLOCK DIAGRAM

Dwg. FP-028-1

s Patented Lossless Current Sensing Eliminates Need

for External Current-Sense Resistor

s Externally Determined Transconductance, with Hi/Lo

Configuration Switched via Serial Port

s Forward or Reverse Torque Serial Port Bit Allows

Improved Speed Disturbance Performance

s Dynamic Braking with User Delay, Activated by

Undervoltage or Serial Port Command

Energy Manager:

s 3.0 V to 5.5 V Operation

s DC-to-DC Converter Maintains r

at Low Supply

s Independent Power-Down (Sleep) Modes for all

Functional Blocks

s Efficient Active Regeneration Supplies Power

During Retract

s Supply Under-Voltage Fault Monitor with

Adjustable Trip Point

s Power-On-Reset Generator for Power Up or

Power Loss with User-Defined Delay

s Chip Powers Up in Sleep Mode for Minimum

Power Dissipation

s External 2 MHz System Clock, or Internal Serial Port

Trimmed 2 MHz Clock

s System Diagnostics

s Uncommitted Op-amp

DATA ENABLE

CLOCK

SERIAL DATA IN

TACH

EXTERNAL

COMMUTATION

BACK-EMF AND

COMMUTATION LOGIC

SLEW

RATE

CONTROL

g

m

ENERGY MANAGER

CONTROLLED RETRACT

DC-DC CONVERSION

SLEEP MODES

UV FAULT

g

m

+

–

+

–

+

–

SPIN

INPUT

SERVO

INPUT

Copyright © 1995, Allegro MicroSystems, Inc.