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
- 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:
• EMC compliant Driver Functions
• Over Current, Over / Under Voltage
Threshold Values
• 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.)
- Standby and Wake-up capability
- Sleep / Wake-up Mode system controlled by the µP and
the LIN Bus
- SOIC 28 Package
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.
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
- Fan cooler
- Air conditioning
- Fuel pumps
- Water and oil pumps
- General purpose DC Motor Regulators
Typical Application Diagram
Vbat
M
R
m
eas
AS8444
TP
LIN
Vbat
VSS
Iref
VDDctrl
VDD
CP2
CP1
Vpump
OUT
CS
CMP
DATAout
CMN
FAIL
PWM
25
26
24
23
22
21
20
19
18
17
16
CLK
DATAin
Tx
Rx1
27
28
RESET
1
D1
Cbat
Tr1
CP12 CP0
VDD = 5 V
CV
D
D
Rref
R
NTC
R
T1
M+
M-
GND_P
Power partControl part
Bus
15
2
3
4
5
6
7
8
9
10
11
12
13
14
VMO
ADC
WD
µP
Q1
OSC1
OSC2
PWMout
VDD GND
(optional)
Rx2
n.c.
CLK
(optional)
CS
INR
ANA
Port1
Port2
SPIout
SPIin
RESET
Tout
GND_P
VSS
AS 8444 / AS 8446
Programmable PWM DC Motor Driver / Controller
FEATURES