U6820bm, Short-circuit protection, Inductance protection – Rainbow Electronics U6820BM User Manual
Page 4: Temperature protection, Esd protection
4
U6820BM
4527A–BCD–03/02
Short-circuit Protection
The current of the output stages is limited by an active feedback control. Short circuit at
one output stage sets the diagnostic Pin 14 (STATUS) to high. In case of both condi-
tions, short circuit at one of the outputs and temperature detection, the affected output is
switched off selectively. It will be activated again after the first new data transfer.
Inductance Protection
Clamping diodes and FETs are integrated to protect the IC against too high or too low
voltages at the outputs. They prevent the IC from latch up and parasitic currents which
may exceed power dissipation.
Temperature Protection
The IC is protected by an overtemperature detection. As soon as the junction tempera-
ture T
j
= 155
°
C typically is exceeded, the diagnostic Pin 14 (STATUS) is set “high”.
General overtemperature detection along with short-circuit condition at a specific output
result in temperature shut down at that specific output. After temperature shut down, the
data input register has to be set again with a hysteresis of typically
∆
T = 15 K
(T
j
= 140
°
C).
ESD Protection
All output stages are protected against electrostatic discharge up to 5 kV (HBM) with
external components (see Figure 5), all other pins are protected up to 2 kV (HBM).
Table 1. Timing of the STATUS Output
Shift Register
Command
Register
Condition
Low-side Switch
High-side Switch
Status
LS1
LS2
LS3
LS4
HS1
HS2
HS3
HS4
Set
Reset
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
All out = OK
off
off
off
off
off
off
off
off
H
New CS
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
All on = OK
on
on
on
on
on
on
on
on
L
0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1
E.g. one on = OK
off
off
off
off
off
off
off
on
L
0 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1
Short at LS3
off
on
on
on
on
on
on
on
H
No short
1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1
Temp & short at HS4
on
on
on
off
on
on
on
on
H
New CS4
1 1 0 0 0 0 1 1 0 0 0 0 0 0 0 0
V
VCC
< 3.7 V = P-ON
off
off
off
off
off
off
off
off
H
P-ON, CS
1 1 1 0 0 0 1 1 x x x x x x x x
CS with less 8 CLK
x
x
x
x
x
x
x
x
H
New CS 8
0 0 0 1 1 1 0 0 x x x x x x x x
CS with more 8 CLK
x
x
x
x
x
x
x
x
H
New CS 2