L9386 STMicroelectronics, L9386 Datasheet - Page 8

• Manufacturer Part Number: L9386
• Description: Dual Intelligent Power Low Side Switch
• Manufacturer: STMicroelectronics

L9386MD
CIRCUIT DESCRIPTION
The L9386MD is a dual low side driver for induc-
tive loads like valves in automotive environment.
The device is enabled by a common CMOS com-
patible ENABLE high signal. The internal pull
down current sources at the ENABLE and INPUT
pins protect the device in open input conditions
against malfunctions. An output slope limitation
for du/dt is implemented to reduce the EMI. An in-
tegrated active flyback voltage limitation clamps
the output voltage during the flyback phase to
50V.
Each driver is protected against short circuit and
thermal overload. In short circuit condition the
output will be disabled after a short delay time
t
until a negative slope occure at the correspondent
input pin. The thermal disable for T
the output will be reseted if the junction tempera-
ture decreases about 20°C below the disable
threshold temperature.
For the real time error diagnosis the voltage and
the current of the outputs are compared with in-
ternal fixed values VO
conditions to recognize open load (R
> 38 ) in ON and OFF conditions. The diagnostic
Figure 5: Application circuit diagram.
8/10
DOL
Controller
+5V
to suppress spikes. This disable is latched
µ P
DIAG1
DIAG2
IN1
IN2
EN
UV
for OFF and IO
L
J
Diagnostic
Control
> 175°C of
UC
20K , R
Output
Control
for ON
Q S
R
Channel 2
Channel 1
L
Delay
Timer
operates also in the extended supply voltage rang
of 4.5V
Also the output voltages VO
against each other in OFF condition with a fixed
offset of VO
To suppress mail VO diagnoses during the fly-
back phases of the compared output, the VO di-
agnostic includes a latch function. Reaching the
flyback clamping voltage VO
nal is reseted by a latch. To activate again this
kind of diagnostic a low signal at the correspon-
dent INPUT or the ENABLE pin must occur (see
also Fig.3).
The diagnostic output level in connection with dif-
ferent ENABLE and INPUT conditions allows to
recognize different fail states, like overtemp, short
to VSS, short to GND, bypass to GND and dis-
connected load (see also page 7 diagnostic ta-
ble).
The diagnostic output is also protected against
short to UD
threshold IO
ternally during the diagnostic overload delay
switch-off time t
Overtemp
Openload
Overload
VS
max
o
, the output current will be limited in-
UV 1,2
. Oversteping the over load current
32V.
DOL
.
GND
to recognize GND bypasses.
R O
C
OUT1
VS
OUT2
1,2
the diagnostic sig-
Z VALVE
are compared
Z VALVE
V Batt