MC33094 View Datasheet(PDF) - Motorola => Freescale
Part Name
Description
Manufacturer
MC33094 Datasheet PDF : 16 Pages
| |||
Vin(-)
SW
Freescale SMeCm3i3c0o94nductor, Inc.
Figure 11. Typical Ignition Circuit
Ignition
+Vbat
15.3 k
2 MB 6 G
330
9 VCC
0.1 µ
Band-Gap Master
Reference Bias
VCC Clamp and
Zener Ref.
10
Input
Comp. and
10 k
7
Negative
Edge Filter
Vin(-)
DI
Output Current
11
Driver and Limiter
DC
Internal
Logic
12
27 k 8
Out
0.1 µ ST
13
CR > CA
Comparator
14
IS
T
Adaptive
Capacitor
Ramp
Capacitor
Stall
Capacitor
3 CA
0.1 µ
4 CR
0.1 µ
15 CS
0.1 µ
55
18 V
4.0 k
200
200
BU931,
MJE5742,
or
MJH10012
56
0.05
5.0 W
Introduction
The MC33094DW is designed for engine compartment
use in 12 V automotive ignition applications to provide high
performance control of the ignition coil when used with an
appropriate Motorola Power Darlington Transistor. Engine
control systems utilizing these devices for ignition coil control
exhibit superior fuel efficiency and lower exhaust emissions
over predecessor systems. The device is designed for single
input control from a Hall sensor to determine crankshaft
position.
The device, a bipolar linear integrated circuit, is built using
high–density Integrated–Injection Logic (IIL) processing
incorporating high current–gain PNP and NPN transistors. All
module inputs are transient voltage protected through the
use of resistors, capacitors, and/or zener diodes working in
conjunction with internal protection elements. These
elements provide protection of critical circuitry from externally
induced high–voltage transients which may degrade the
devices operational performance. At the module level, it is
recommended the VCC pin of the device be transient
decoupled using an external resistor and capacitor to work in
conjunction with the on–chip internal zener string to provide
robust module protection of the device power pin. The D input
of module should be protected from transients through the
use of an external resistor and zener diode. The Start Wire of
the module should be decoupled through the use of two
resistors and a capacitor to work in conjunction with the
on–chip internal clamp (Figure 11).
The output of the device incorporates a high current–gain
PNP designed to drive an external power Darlington
transistor to provide control of the ignition coil. The output
drive is carefully synchronized with the output from the
distributor. The charging and discharging of three capacitors,
external to the device, provide timing signals which program
the dwell and charge time control of the ignition coil over a
wide rpm range.
The timing and charge/discharge rates of the three
external capacitors are accurately controlled by internal
circuitry acted upon by sensor and distributor signal detection
of the device.
A feedback path from the emitter of the external power
Darlington transistor to the device provide monitoring of the
ignition coil current. An internal comparitor of the device
senses and limits the maximum ignition coil current to
approximately 6.5 amps. Other circuitry within the device
provides an interruption of the coil current so as to generate
the spark, or slowly discharges the coil in a controlled
manner so as to prevent a spark and limit the total module
energy dissipation.
When the external Darlington is switched off, the
Darlington collector will instantly experience a dramatic
increase in voltage as a result of the collapsing field of the
ignition coil (inductive kick). The external voltage divider
working in conjunction with the internal device zener string
and power PNP form a dynamic clamp which limits the
inductive kick voltage to less than 350 V. This feature
protects the Darlington transistor from damaging stress or
breakdown.
10
For More Information On This ProdMuOcTtO, ROLA ANALOG IC DEVICE DATA
Go to: www.freescale.com
Share Link: 