Rainbow Electronics BA3950A - Manual (Page 7)

205
Regulator ICs BA3950A
(4) Overcurrent protection circuit
An overcurrent protection circuit is installed in each out-
put system, based on the respective output current. This
prevents IC destruction by overcurrent, by limiting the
current with a curve shape of “7” in the voltage-current
graph. The IC is designed with margins so that current
flow will be restricted and latching will be prevented even
if a large current suddenly flows through a large capaci-
tor. Note that these protection circuits are only good for
preventing damage from sudden accidents. Make sure
your design does not cause the protection circuit to oper-
ate continuously under transitional conditions (for
instance, when output is clamped at 1V
F
or higher). Note
that the circuit ability is negatively correlated with temper-
ature.
(5) Thermal protection circuit
A built-in thermal protection circuit prevents thermal
damage to the IC. All outputs are switched OFF when the
circuit operates, and revert to the original state when
temperature drops to a certain level.
(6)
Improving ripple rejection by capacitors
Ripple rejection of the CDP and MAIN outputs can be im-
proved by installing a capacitor that reduces the AC gain.
(7)
Malfunction in intense electric fields
Note that bringing the IC into an intense electric field
(such as a radio relay station) may result in malfunction.
F
Thermal derating curve
Estimate of allowable power dissipation (P
MAX.
)
S
Power consumed by CDP P
1
= (V
CC
*
CDP) maximum load current of CDP
S
Power consumed by
µ
-COM P
2
= {V
CC
*
(
µ
-COM)} maximum load current of
µ
-COM
S Power consumed by MAIN P
3
= (V
CC
* MAIN) maximum load current of MAIN
S
Power consumed internally by each circuit P
4
= V
CC
supply current
P
MAX.
= P
1
)
P
2
)
P
3
)
P
4