AS 8444 / AS 8446
Programmable PWM DC Motor Driver / Controller
FEATURES
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.
Key Features
-
-
-
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
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.
-
-
-
-
-
Driver fulfils EMC Level 5 (CISPR 25)
Dynamically self-adjusting slew rate regulated switching
technology
-
-
-
-
Fully protected by programmable failure handling
procedures via µP
To simplify the application of this motor regulator in
complex systems (e.g. automotive environment) the circuit
is endowed with a LIN bus interface.
Fast Over Current and Over / Under Voltage Detection
and Protection, Battery Voltage Monitoring
External and On Chip Temperature Detection and
Protection
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.
Motor Current and Speed Measurement with a shunt
resistor and capability of trimming the chip for an
external shunt value
Applications
-
-
LIN Bus Interface
Programmable Parameters:
-
-
-
-
-
Fan cooler
Air conditioning
• EMC compliant Driver Functions
• Over Current, Over / Under Voltage
Threshold Values
Fuel pumps
Water and oil pumps
General purpose DC Motor Regulators
• Motor Failure Threshold Levels
• Motor Current Measurement Range
• Trimming for the current measurement shunt
• PWM Frequency, Charge Pump Monitor
Charge Pump to control high side drivers
Integrated 5 V Power Supply for external components
(µP, etc.)
Typical Application Diagram
-
-
Power part
Control part
Vbat
Cbat
1
28
27
CMN
CMP
VSS
-
-
Standby and Wake-up capability
2
3
4
5
6
7
8
9
GND_P
Tr1
OUT 26
VMO
Vbat
TP
Sleep / Wake-up Mode system controlled by the µP and
the LIN Bus
Vpump25
Bus
(optional)
CP12
Rref
CP0
24
CP2
23
CP1
PWMout
FAIL
CS
INR
22
µP
VDDctrl
CS
ANA
CLK
-
SOIC 28 Package
VDD = 5 V
D1
(optional)
Q1
21
VDD
ADC
LIN
OSC2
OSC1
VDD
M+
M-
20
Iref
RESET 19
10 n.c.
11 Tx
GND
Port1
Port2
18
RT1
WD
General Description
M
12 Rx1
13
Rx2 17
RNTC
16
RESET
Tout
DATAin
PWM
SPIout
SPIin
14
15
CLK
DATAout
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.
VSS
GND_P