8980

SPINDLE & VOICE-COIL

ACTUATION MANAGER/DRIVER

115 Northeast Cutoff, Box 15036

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

FUNCTIONAL BLOCK DIAGRAM

Dwg. FP-028B

DIGITAL MUX OUT

DATA ENABLE

2 V

REF

V

REF

ANALOG MUX 1

CLOCK

TACH

UV TRIP ADJUST

ANALOG MUX 2

EXTERNAL

COMMUTATION

2 MHz CLOCK

RETRACT

SERIAL DATA IN

BACK-EMF AND

COMMUTATION LOGIC

CONFIGURATION

CONTROL

SERVO CONTROL

SLEW

RATE

CONTROL

POWER-ON

RESET (TO

µC)

g

m

R

gm

R

gm

ENERGY MANAGER

CONTROLLED RETRACT

DC-DC CONVERSION

SLEEP MODES

UV FAULT

THERMAL SHUTDOWN

TUNABLE

LOW-PASS

FILTER

NOTCH

FREQUENCY,

DEPTH, &

DAMPING

OVER-VELOCITY FAULT

12-BIT

SERVO-

DEMAND

DAC

8-BIT

SPIN-DEMAND

DAC

IN / OUT MUX

g

m

Energy Manager:

s 3.0 V to 5.5 V Operation

s Independent Power-Down (Sleep) Modes for all

Functional Blocks

s Efficient Synchronous Rectification Supplies Power

During Blackout

s Thermal Fault Shutdown Circuitry

s Trimmed Bandgap Voltage Reference

s Smart DAC Reference Generator

s Programmable Voltage Reference for Relative Ground

s Over-Velocity Fault Circuitry

s Supply Under-Voltage Monitor with Adjustable

Trip Point

s System Diagnostics Data Out

s Power-On Reset Generator

Spindle Motor Controller/Driver:

s Low r

s Back-EMF Circuitry Eliminates Hall-Effect Sensors

s Programmable Slew Rate Eliminates Snubbers

s Lossless Current Sensing

s Improved Speed Disturbance Performance

s Dynamic Braking with Delay

s Active Braking

Servo Compensator/Notch:

s Over-Velocity Fault Circuitry

s 12-Bit Servo-Demand DAC

s Programmable Complex Pole Low-pass-Filter

s Programmable Notch Frequency, Depth, and Damping

Copyright © 1992, 1994, Allegro MicroSystems, Inc.