MB39A112 Datasheet, PDF (12/35 Pages) Fujitsu Component Limited. – 3-ch DC/DC Converter IC

MB39A112
(2) Undervoltage Lockout Protection Circuit Block (UVLO)
The transient state or a momentary decrease in supply voltage, which occurs when the power supply is turned
on, may cause the IC to malfunction, resulting in breakdown or degradation of the system. To prevent such
malfunctions, under voltage lockout protection circuit detects a decrease in internal reference voltage with respect
to the power supply voltage, turns off the output transistor, and sets the dead time to 100% while holding the
CSCP terminal (pin 14) at the “L” level.
The circuit restores the output transistor to normal when the supply voltage reaches the threshold voltage of the
undervoltage lockout protection circuit.
(3) Protection Circuit Operating Function Table
This table refers to output condition when each protection circuit is operating.
Operating circuit
CH1
OUT1
CH2
OUT2
Short-circuit protection circuit
H
H
Under-voltage lockout circuit
H
H
CH3
OUT3
H
H
The latch can be reset as follows after the short-circuit protection circuit is actuated.
Recycling VCC resets the latch whenever the short-circuit protection circuit has been actuated.
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