OMO ElectronicOMO Electronic
Expand menu
Hello, Sign inMy Account
0 Cart

L9524C-TR

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27
Functional description L9524C
16/27
In order to report the occurrence of any of the above-listed failures to the diesel engine
management system the L9524C provides two protocols: go/no-go protocol for mode 1 and
serial protocol for modes 2 to 6.
The go/no-go protocol is only able to report if any of the above-listed failures occurred. This
is done according to the following table:
Note: overcurrent failures are stored until power-down.
The serial protocol is able to report different kinds of failures and to assign them to the
corresponding glow plugs. Therefore, occurring failures are written into an internal 8-bit
failure register:
Bits 1 to 6 are assigned to the glow plugs. Depending on bit 7 they show open-load (bit 7 is
low) or overcurrent failures (bit 7 is high). Bit 8 shows if there is any of the listed failures
(“module failure”). In case of a battery under voltage failure bits 7 and 8 are high and all
other bits are low as long as there is no overcurrent failure stored.
For transmitting the contents of the failure register the PWM signal applied to the CI pin is
used as clock input: at any falling edge of the CI signal (see section “Control input”) the DO
pin shows the value of the next bit of the bit stream after t
DO del
.
Table 7. Go / no-go protocol description
V
CI
V
DO
at “no failure” V
DO
at “any failure”
V
CI off
V
DOL
V
VS
V
CI on
V
VS
V
DOL
Table 8. Failure register description
Bit Meaning of high state
1 Open-load or overcurrent
(1)
failure at glow plug 1
1. overcurrent failures are stored until power-down
2 Open-load or overcurrent
(1)
failure at glow plug 2
3 Open-load or overcurrent
(1)
failure at glow plug 3
4 Open-load or overcurrent
(1)
failure at glow plug 4
5 Open-load or overcurrent
(1)
failure at glow plug 5
6 Open-load or overcurrent
(1)
failure at glow plug 6
7
Overcurrent failure at any glow plug
(1)
or
battery voltage (V
BAT
) is too low
(2)
(“battery undervoltage”)
2. if battery voltage is too low (“battery under voltage”) bits 7 and 8 are high
8
One or more of the following failures (“module failure”):
any switch is defect
supply voltage (V
VS
) is too low (“undervoltage”)
supply voltage (V
VS
) is too high (“overvoltage”)
junction temperature (T
J
) is too high
charge pump voltage (V
CP
) is too low (“charge pump undervoltage”)
battery voltage (V
BAT
) is too low
(2)
(“battery under voltage”)
L9524C Functional description
17/27
Each transmission frame consists of a beginning delimiter (one low bit) followed by the 8 bits
of the failure register beginning with bit 1. After the ending delimiter (one high bit) the
diagnostic output stage is inactive and is resistively pulled up to V
VS
.
The L9524C starts transmitting the first frame at the very first falling edge of the CI signal
after power-on. Since at that time the contents of the failure register are clear the first 9 bits
(beginning delimiter followed by the contents of the 8-bit failure register) which are
transmitted are always low. The L9524C repeats transmission of the frame every 32 falling
edges of the CI signal. Only during the time when the diagnostic output stage is inactive (i.e.
between the transmission of two frames) the contents of the failure register can be written.
Figure 7. Serial diagnostic interface protocol
4.5 Current monitoring
The L9524C is able to monitor the current through 6 glow plugs by measuring the voltage
drop across sense resistors. Therefore, there are 4 positive sense input pins (SP1, SP2,
SP3, SP4) and 6 negative sense input pins (SN1, SN2, SN3, SN4, SN5, SN6). The sense
input pins must be connected to the sense resistors according to the following table:
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
bit 8
low
high
high
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
bit 8
low
beginning
delimiter
ending
delimiter
contents of failure register
(all bits='low' at 1st frame)
contents of failure register
diagnostic
output
stage
inactive
beginning
delimiter
ending
delimiter
first frame frame
01234567891011
31
0
12345678910
...
V
VS
V
CI
V
CI off
V
CI on
V
DO
V
VS
V
DOL
t
t
t
...
...
...
Table 9. Sense input pin connection
Sense resistor of glow plug Positive sense input pin Negative sense input pin
1SP1SN1
2SP2SN2
3SP3SN3
4SP4SN4
5SP2SN5
6SP4SN6
Functional description L9524C
18/27
In relay mode (modes 1 and 2) the positive sense input pins are short-circuited since the
relay is the only switch. In transistor mode (modes 3 to 6) glow plug 5 is switched with
transistor 2 and glow plug 6 with transistor 4. Therefore only 4 positive sense input pins are
necessary.
If the voltage drop across the sense resistor is less than V
OL
for at least t
OL fil
an open-load
failure is detected as long as V
VS
> V
VS ol
. If it is greater than V
OC
(see below for definition)
for at least t
OC fil
an overcurrent failure is detected and the corresponding switch is switched
off and remains switched off until power-down. The threshold for overcurrent failures V
OC
can be varied by the voltage applied to the OCT pin (see section “Overcurrent threshold
variation”).
In modes 1 to 4 the overcurrent threshold is constant with respect to the temperature
(TC
OC
= 0). But in modes 5 and 6 the overcurrent threshold increases linearly with the
temperature to compensate the first-order temperature coefficient of the R
DS(on)
of the
external power MOSFET’s which are used as sense resistors in these modes:
Equation 1
V
OC
= V
OC 0
(1 + TC
OC
( + 40C)).
4.6 Switch monitoring
The L9524C monitors the voltages across the glow plugs (using the negative sense input
pins SN1, SN2, SN3, and SN4) to detect if the corresponding switches work properly or not.
A switch is detected as defect if it is switched on but the voltage across the corresponding
glow plug(s) is less than V
SD
for at least t
SD fil
or if it is switched off but the voltage across
the glow plug(s) is greater than V
SD
for at least t
SD fil
.
4.7 Thermal shutdown
If the junction temperature becomes greater than T
JSD
all glow plugs are switched off. They
are switched on again if the junction temperature falls below T
JSD
.
4.8 Gate drivers
The L9524C contains four gate drivers (Gx pins) for external n-channel power MOSFET’s in
high-side configuration. Each gate driver provides a slope control by charging and
discharging the gates of the external power MOSFET’s with constant currents (I
G on
or I
G
off
). To adjust the slopes these currents can be varied using the CUR pin (see section “Gate
charge/discharge current variation”). The charging current source is supplied by an external
capacitor connected to the charge pump output (CP) pin. The gate-to-source voltages are
limited internally and without supply voltage (V
VS
) the gates and the sources of the external
power MOSFET’s are short-circuited.
During free-wheeling of inductive loads the gates of the external power MOSFET’s are
clamped to V
G cl
. As a result, the power MOSFET’s become conducting and the energy in
the inductive loads is recirculated through the power MOSFET’s.
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27

L9524C-TR

Mfr. #:
Buy L9524C-TR
Manufacturer:
STMicroelectronics
Description:
Linear Voltage Regulators Glow Plug System Control IC Six
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union

Products related to this Datasheet