AS 8444 / AS 8446
Programmable PWM DC Motor Driver / Controller
FEATURES
Key Features
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Programmable PWM DC Motor Driver / Controller with
µP Interface (Three Wire Interface)
Programmable Functions and Parameters for Motor
Current, Voltage and Speed Regulation
Single Voltage Supply in the range
Vbat = 6.0 V to 30 V (Vbat,max = 40 V)
Total Power Efficiency up to 96 %
Low RF Emission within the whole frequency range due
to an integrated special EMC compliant driver
No EMC Filters required
Driver fulfils EMC Level 5 (CISPR 25)
Dynamically self-adjusting slew rate regulated switching
technology
Fully protected by programmable failure handling
procedures via µP
Fast Over Current and Over / Under Voltage Detection
and Protection, Battery Voltage Monitoring
External and On Chip Temperature Detection and
Protection
Motor Current and Speed Measurement with a shunt
resistor and capability of trimming the chip for an
external shunt value
LIN Bus Interface
Programmable Parameters:
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EMC compliant Driver Functions
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Over Current, Over / Under Voltage
Threshold Values
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Motor Failure Threshold Levels
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Motor Current Measurement Range
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Trimming for the current measurement shunt
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PWM Frequency, Charge Pump Monitor
Charge Pump to control high side drivers
Integrated 5 V Power Supply for external components
(µP, etc.)
Standby and Wake-up capability
Sleep / Wake-up Mode system controlled by the
µP
and
the LIN Bus
SOIC 28 Package
Bus
It is an advanced PWM DC motor controller subsystem with
an excellent EMC behavior targeted especially for high
current automotive applications. The optimization of the
EMC behavior of the entire module without external
components makes it easier to implement in harsh
environments.
The programmability of parameters and functions allows the
adaptation of the AS8444 to a wide range of applications.
So the system can act either as a motor current or motor
speed or motor voltage regulator. Also a full diagnosis of
motor failures and power FET failures, over temperature
and over/under voltage can be formed by programmable
failure handling procedures using the motor characteristic
and the real time measured motor current, motor speed and
battery voltage.
To simplify the application of this motor regulator in
complex systems (e.g. automotive environment) the circuit
is endowed with a LIN bus interface.
There are two versions of this chip AS8444 and AS8446.
The only difference between the AS8444 and the AS8446 is
the start up behavior after system wake up or battery
connection.
Applications
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Fan cooler
Air conditioning
Fuel pumps
Water and oil pumps
General purpose DC Motor Regulators
Typical Application Diagram
Control part
Power part
Cbat
1
2
3
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Vbat
CMN
CMP
VSS
28
GND_P
27
OUT
Tr1
CP12
CP0
Rmeas
AS8444
VMO
Vbat
TP
FAIL
CS
ADC
LIN
n.c.
26
(optional)
4
5
Vpump
25
CP2
24
CP1
23
VDDctrl
22
VDD
21
Iref
20
RESET
19
WD
18
Rx2
17
PWM
16
CLK
15
PWMout
INR
CS
ANA
CLK
GND
Port1
Port2
6
7
8
9
10
µP
(optional)
Q1
OSC2
OSC1
VDD
VDD = 5 V
Rref
R
T1
R
NTC
CVDD
D1
M+
General Description
The AS8444 is a complete and fully protected PWM DC
motor driver/controller, which could be implemented by
interfacing a low cost 8-bit
µP
and a high-side N-channel
power FET switch.
11
Tx
12
Rx1
13
DATAin
14
DATAout
M
M-
VSS
RESET
Tout
SPIout
SPIin
GND_P
AMSCO [ AUSTRIAMICROSYSTEMS AG ]
