AMC8500 Datasheet, PDF (13/27 Pages) List of Unclassifed Manufacturers – TWO PHASE VARIABLE SPEED FAN MOTOR CONTROLLER

Preliminary Specification
aMC8500
Figure 20- Motor Supply Powered Unbuffered Hall
V_M
Asahi Kasei _R1
HW-101A
H
V_DD 12
3
4
Under Voltage
Lockout
Hall Amplifier
Non-Overlap
Commutation
When powering an unbuffered Hall sensor from motor voltage V_M,
resistor R1 is required. This resistor sets the Hall operating current
and places the output within the input common mode voltage range
of the Hall Amplifier.
Figure 22- Op Amp Powered Unbuffered Hall
V_M
V_DD 12
3
H
Toshiba
4 ^TSH124
5
Reference
Under Voltage
Lockout
7
Op Amp
8
Hall Amplifier
Non-Overlap
Commutation
9
The Op Amp output can be used as alternative method for powering
unbuffered Hall sensors that require less than 10 mA. This method
eliminates the need for bias resistor R1 while also preserving the
automatic power down feature. With this bias method the reference
output is essentially unloaded.
Figure 24- Reference Biased Buffered Hall
V_M
V_DD 12
3
R1
H
Ana Chip
4 ^ATS177
5
Reference
Under Voltage
Lockout
Hall Amplifier
Non-Overlap
Commutation
Figure 21- Reference Powered Unbuffered Hall
V_M
V_DD 12
3
H
Toshiba
4 ^TSH124
5
Reference
Under Voltage
Lockout
Hall Amplifier
Non-Overlap
Commutation
Unbuffered Hall sensors that require less than 10 mA can be
powered directly from the Reference output thus eliminating the
need for bias resistor R1. This bias method will disable the
automatic power down feature if the sensors require more than
2.0 mA.
Figure 23- Motor Supply Biased Buffered Hall
V_M
R2
R3
V_DD 12
3
R1
H
Ana Chip
4 ^ATS177
Under Voltage
Lockout
Hall Amplifier
Non-Overlap
Commutation
Pull-up resistor R1 is required when using buffered Hall sensors that
have an open collector output. Resistors R2 and R3 bias the unused
amplifier input to a level that is within its input common mode range.
Figure 25- Reference Buffer
V_M
KEC
KTA1270
0.1
5
Load
Reference
100
V_DD 12
Under Voltage
Lockout
Resistor R1 is required for buffered Hall sensors with an open
collector output. Resistors R2 and R3 can be eliminated by biasing
the unused amplifier input from the reference.
With the addition of an economical PNP transistor, the Reference
output current can be boosted above 100 mA. This simple buffer
circuit will not have the benefit of maintaining short circuit protection.
© Andigilog, Inc. 2006
- 13 -
www.andigilog.com
August 2006 - 70A04018