September 1997
1/8
This is preliminary information on a new product in development or undergoing evaluation. Details are subject to change without notice.
VB125SP
HIGH VOLTAGE IGNITION COIL DRIVER
POWER IC
s
PRIMARY COIL VOLTAGE INTERNALLY SET
s
COIL CURRENT LIMIT INTERNALLY SET
s
LOGIC LEVEL COMPATIBLE INPUT
s
BATTERY OPERATION
s
SINGLE FLAG-ON COIL CURRENT
s
TEMPERATURE
COMPENSATED
HIGH
VOLTAGE CLAMP
DESCRIPTION
The VB125SP is a high voltage power integrated
circuit
made
using
SGS-THOMSON
Microelectronics
Vertical
Intelligent
Power
Technology, with vertical current flow power
darlington and
logic level compatible driving
circuit.
The VB125SP can be directly biased by using the
12V battery voltage, thus avoiding to use a low
voltage regulator. It has built-in protection circuits
for coil current limiting and collector voltage
clamping. It is suitable as smart, high voltage, high
current interface in advanced electronic ignition
system.
TYPE
V
CL
I
CL
I
CC
VB125SP
370 V
9 A
200 mA
DRIVER
VOLTAGE
GND (Power)
INPUT
FLAG
GND (Control)
THERMAL
FLAG
9
10
7
8
TAB
REFERENCE
PROTECTION
R
SENSE
6
C
S
V
CC
HV
C
*
BLOCK DIAGRAM
1
10
PowerSO-10
1
TARGET DATA
(*)
Pins 1...5
2/8
VB125SP
ABSOLUTE MAXIMUM RATING
THERMAL DATA
CONNECTION DIAGRAM
PIN FUNCTION
Symbol
Parameter
Value
Unit
HV
C
Collector Voltage (Internally Limited)
-0.3V to V
CLAMP
V
I
C
Collector Current (Internally Limited)
10
A
V
CC
Driving Stage Supply Voltage
-0.2 to 40
V
I
CC
Driving Circuitry Supply Current
400
mA
I
S
Logic Circuitry Supply Ccurrent
100
mA
V
IN
Input Voltage
-0.3 to 6
V
P
TOT
Power Dissipation
TBD
W
V
ESD
ESD Voltage (HVC Pin)
-4 to 4
KV
V
ESD
ESD Voltage (Other Pin)
-2 to 2
KV
T
j
Operating Junction Temperature
-40 to 150
C
T
STG
Storage Temperature Range
-55 to 150
C
R
thj-case
Thermal Resistance Junction - Case
MAX
1.2
C/W
R
thj-amb
Thermal Resistance Junction - Ambient
MAX
62.5
C/W
No
Name
FUNCTION
1-5
GND
Emitter Power Ground
6
V
CC
Logic Supply Voltage
7
GND
Control Ground (*)
8
C
S
Logic Level Supply Voltage Filter Capacitor
9
INPUT
Logic Input Channel
10
FLAG
Diagnostic Output Signal
TAB
HVC
Primary Coil Output Driver
1
1
5
6
10
GND
GND
GND
GND
GND
GND
V
CC
Cs
INPUT
FLAG
HVC
(*)
Pin 6 must be connected to pins 1-5 externally
3/8
VB125SP
ELECTRICAL CHARACTERISTICS (V
bat
= 6 to 24V; -40
C<T
j
<125
C; R
coil
= 400 to 700m
; L
coil
= 2
to
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
CL
High Voltage Clamp
I
C
= 6.5 A; (See Note 2)
340
370
400
V
V
CE(sat)
Saturation Voltage of the Power
Stage
I
C
= 5A; V
in
= 4V (See Note 3)
2
V
I
CC(off)
Power Off Supply Current
V
in
=0.4V V
bat
= 14V(Notes 4-5)
V
in
=0.4V
V
bat
= 24 V
20
80
mA
mA
I
CC(on)
Power On Supply Current
V
In
= 4 V
V
bat
<14V (Note 4-5)
V
in
= 4 V
V
bat
= 24 V
220
300
mA
mA
I
CL
Coil Current Limit
V
in
= 4 V (See Note 6-7)
8
10
A
V
inH
High Level Input Voltage
4
V
V
inL
Low Level Input Voltage
0.8
V
V
IN(hyst.)
Input Hysteresis Voltage
0.4
V
I
inH
High Level Input Current
V
in
= 4 V
10
150
A
I
inL
Low Level Input Current
V
in
= 0.8 V
-100
A
V
diagH
High Level Diagnostic Output
Voltage
R
EXT
= 22 K
C
EXT
= 1 nF
(See Note 8)
3.5
5.5
V
V
diagL
Low Level Diagnostic Output
Voltage
R
EXT
= 22 K
C
EXT
= 1 nF
(See Note 8)
0.5
V
I
diagTH
Current Threshold Level Diag-
nostic
T
j
= 25
C (See Note 7and fig. 5)
4.25
4.5
4.75
A
I
diag
High Level Flag Output Current
I
C
>I
DiagTH
(See Note 7)
0.5
mA
I
diag(leak)
Leakage Current on Flag Output
V
in
= LOW
10
A
V
F
Antipallel Diode Forward Voltage I
C
= -1 A
2
V
E
s/b
Single Pulse Avalanche Energy
300
mJ
T
j
Thermal Output Current Control
IN = ON (See Note 9)
150
C
t
d(on)
Turn-on Delay Time of Output
Current
(See Note 10)
TBD
s
t
d(off)
Turn-off Delay Time of Output
Current
(See Note 11)
TBD
s
t
d(off)
Turn-off Delay Time of Output
Current
(See Note 11)
TBD
s
nV
Z
HVC
PWR GND
V
CE
[V]
10
20
30
40
I
C
[mA]
slope
Ri
FIGURE 1: Temperature Compensated High
Voltage Clamp
Shown in Figure 1
R
sens
100
200
300
400
nV
Z
V
CL
R
ii
R
i1
KV
be
6mH; unless otherwise specified; See Note 1)
FIGURE 2: Electrical Characteristic of the Circuit
4/8
VB125SP
NOTE 1 Parametric degradation are allowed with 6V < V
bat
< 10V and V
bat
> 24V.
NOTE 2 In the high voltage clamping structure of this device a temperature compensation has been implemented. The
circuit schematic is shown in fig. 1. The KVbe cell takes care of the temperature compensation. The whole
electrical characteristic of the new circuit is shown in fig. 2. Up to V
CE
=nV
Z
no current will flow into the collector (just the
leakage current of the power stage); for nV
Z
< V
CE
< V
CL
a current begins to flow across the resistances of the KVbe
compensation circuit (typical slope
20 K
) as soon as the Vcl is reached the dinamic resistance drop to ~ 4
to
protect the device against overvoltage (See Fig. 3).
NOTE 3 The saturation voltage of the Power stage includes the drop on the sensing resistor.
NOTE 4 Considering the different ways of operation of the device (with or without spark, etc...) there are some short
periods of time in which the output terminal (HV
C
) is pulled below ground by a negative current due to leakage
inductances and stray capacitances of the ignition coil.With VIPower devices, if no corrective action is taken, these
negative currents can cause parasitic glitches on the diagnostic output. To kill this potential problem, a circuit that avoids
the possibility for the HV
C
to be pulled undeground, by sending the required negative current from the battery is
implemented in the VB125SP.For this reason there are some short periods in which a current exceeding 220 mA flows
in the pin V
D
.
NOTE 5 A zener protection of 16V (typical) is placed on the supply pin (V
CC
) of the chip to protect the internal circuitry.
For this reason, when the battery voltage exceedes that value, the current flowing into V
cc
pin can be greater than the
maximum current specified at V
bat
=14V (both in power on and power off condictions) : it will be limited by an internal
resistor.
NOTE 6 The primary coil current value Icl must be measured 1 ms after desaturation of the power stage.
NOTE 7 These limits apply with regard to the minimum battery voltage and resistive drop on the coil and cables that permit
to reach the limitation or diagnostic level.
NOTE 8 No internal Pull-Down.
NOTE 9 Tj
min
= 150
C means that the behaviour of the device will not be affected for junction temperature lower than
150
C. For higher temperature, the thermal protection circuit will begin its action reducing the Icl limit according with the
power dissipation. Chip temperature is a function of the Rth of the whole system in which the device will be operating
(See Fig.4).
NOTE 10 Propagation Time measured from input voltage rising edge to 50% of output voltage falling edge.
NOTE 11 As soon as the input signal is switched low the stored charges in the base of the power transistor are removed
and the so called Turn-off Delay Time of Coil Current begins; after at the Turn-off Fall Time of Coil Current starts
and, at the same time, the HVC rises.
t
dLH
is defined as the time between the negative edge of the input pulse to the point where the HVC reaches 100V.
t
fLH
is defined as the delay between the 90% and the 10% of the coil current.
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