Application Note
12
2015-02-11
Revision 1.0
ISO2H823V2.5 Evaluation Board
Board Manual
Functional Description
Figure 11
SPI Mode 3, MS0 = 1, MS1 = 1
2.3
Process Side
2.3.1
Output Stage
Each channel contains a high-side power FET that is protected by embedded protection functions. The continuous
current for each channel is 600 mA nominal, which depends on the cooling conditions and the total power
dissipation.
2.3.1.1
Output Stage Control
Each output is independently controlled by an output latch and a common reset line via the pin ODIS that disables
all eight outputs and resets the latches.
2.3.1.2
Protection Functionality
Power Transistor Overvoltage Protection
Each of the eight output stages has it’s own zener clamp that causes a voltage limitation at the power transistor
when solenoid loads are switched off.
V
ONCL
is then clamped to 52 V (typ.).
Power Transistor Overload Protection
The outputs are provided with a linear current limitation, which regulates the output current to the current limit value
in case of overload. The electrical operation point does not lead to a shutdown.
The excess power dissipation in the power transistor during current limitation will lead to a rapid increase of the
junction temperature. When the junction temperature exceeds 150°C (typ.) the output will switch off and will switch
on again when the junction temperature has cooled down by a temperature hysteresis of 15K (typ.). Therefore
during overload a thermal on-off toggling may occur.
SCLK
SDI
CS
SDO
uc_spi_mode 3.vsd
MS B
LS B
UV
MV
CF
C3
C2
C1
C0
0
C4
0
0
Checksum
Checksum / Diagnosis
A6
A5
A 4
A 3
A 2
A 1
A 0
0
0
0
0
0
0
0
0
Register -Address (R/W)
D7
D6
D5
D4
D3
D2
D1
D0
R
Read=0
Value „Zero“ for CRC
Value (Read )
C3
C2
C1
C0
C4
MS B
LS B
MS B
LS B
Collective Diagnosis
CD7
CD6
CD5
CD4
CD3
CD2
CD1
CD0
B it23
B it16
B it15
B it8
B it7
B it0
MS B
LS B
UV
MV
CF
C3
C2
C1
C0
0
C4
0
0
Checksum
Checksum / Diagnosis
A6
A5
A 4
A 3
A 2
A 1
A 0
D7
D6
D5
D4
D3
D2
D1
D0
Register -Address (R/W)
d.c.
W
Write=1
Value (Write)
C3
C2
C1
C0
C4
MS B
LS B
MS B
LS B
Collective Diagnosis
CD7
CD6
CD5
CD4
CD3
CD2
CD1
CD0
B it23
B it16
B it15
B it8
B it7
B it0
SDI
SDO
READ
WRITE
d.c.
d.c.
d.c.
d. c.
d. c.
d. c.
d. c.
