AMC8500 Datasheet, PDF (7/27 Pages) List of Unclassifed Manufacturers – TWO PHASE VARIABLE SPEED FAN MOTOR CONTROLLER

Preliminary Specification
aMC8500
Figure 13- Representative Block Diagram
12 V
Reference
Output
5
Non-Inverting
Input
7
Inverting
Input
8
Output
9
Minimum
Speed Set
Input
6
Speed Control
Input ₁₀
Reference
Op Amp
Oscillator
R
Hall +
V_{DD 12 Input 3}
Hall -
Input 4
Under Voltage
Lockout
Hall Amplifier
Non-Overlap
Commutation
Fault Timer
Power Down
Kick Start
Min Speed
Comparator
PWM
Comparator
PWM
Logic
Digital
Detector
H
SN
M
Phase 1
NS
Phase 2
Output 16
1 Output
Motor
Drives
Thermal
Shutdown
Current
Limit
Latch
R
Q
S
10 μA
Current Limit
Comparator
Frequency
Generator /
Rotor Lock
Output
15
13
Power
Ground
2
Current
Limit
Set
Signal Ground 11
14 Slope Select
INTRODUCTION
The aMC8500 is a full featured two phase half wave variable speed brushless motor controller containing all the required
functions for implementing a fan control system. Motor control features consists of a selectable slope pulse width modulator
(PWM) with double pulse suppression for efficient speed control that is compatible with an analog voltage or a varying duty
cycle digital pulse train, a programmable minimum speed set input, and an uncommitted op amp with a pinned out reference
for speed control signal scaling, Hall sensor amplifier with propriety noise immunity circuitry for proper drive sequencing,
non-overlapping commutation drive for reduced supply current spiking, on-chip 0.5 Ω power MOSFETs for direct coil drive.
Protective and diagnostic features include an internal fault timer with auto start retry, motor kick start timer to insure proper
start up, programmable cycle-by-cycle current limiting, power supply under voltage lockout, and over temperature thermal
shutdown, and a combined frequency generator / rotor lock output for status reporting. Also included is a selectable
automatic low current power down mode aimed at power sensitive applications.
The aMC8500 is designed for use in thermal open or closed loop systems. It can be controlled by simple NTC or PTC
thermistors, Simistor™ silicon temperature sensors, or by complex digital or microcontroller based temperature monitors.
FUNCTIONAL DESCRIPTION
A representative block diagram is shown in Figure 13 and a detailed discussion on each of the functional blocks and
features are given in the following sections. A complete list of the pin functions with a brief description is shown in Figure 33.
© Andigilog, Inc. 2006
-7-
www.andigilog.com
August 2006 - 70A04018