Datasheet

L6377 Demagnetisation of inductive loads
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8 Demagnetisation of inductive loads
The L6377 has an internal clamping zener diode able to demagnetise inductive loads. Note
that the limitation comes from the peak power that the package can handle. Attention must
be paid to a proper thermal design of the board. If, for whatever reason (load current or
inductive value too big) the peak power dissipation is too high, an external Zener plus Diode
arrangement, can perform a demagnetisation versus Ground or versus V
s
(see fig 5 and 6).
The breakdown voltage of the external Zener Diode must be chosen considering the internal
clamping voltage (V
cl
) and the supply voltage (V
s
) according to:
V
z
< V
cl(min)
-V
s(max)
for demagnetisation versus ground or
V
s(max)
<V
z
<V
cl(min)
for demagnetisation versus V
s
.
Figure 7. External demagnetisation circuit (versus ground)
Figure 6. Input comparator hysteresis
V
i+
V
s
V
out
100mV
D94IN079
V
i-
100mV
DRIVER
V
S
OVC
OUT
R
S
SHORT CIRCUIT
CONTROL
UV
CURRENT
LIMIT
D94IN112
V
Z
V
Z
< V
cl (min)
- V
S (max)