MB3885PFV FUJITSU [Fujitsu Component Limited.], MB3885PFV Datasheet - Page 14

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MB3885PFV

Manufacturer Part Number
MB3885PFV
Description
1-channel DC/DC Converter IC with Synchronous Rectifier
Manufacturer
FUJITSU [Fujitsu Component Limited.]
Datasheet
14
MB3885
2. Control Functions
3. Protective Functions
(1) Timer Latch Short Circuit Protection (SCP)
(2) Undervoltage Lockout Circuit Block (UVLO)
(3) Overvoltage Protection Block (OVP)
Output ON/OFF control is provided by using the CS terminal (pin 6) setting functions.
The short circuit protection comparators read the output voltage levels. If the output voltage falls below the short
detection voltage, the timer circuit is activated to start charging the external capacitor Cscp connected to the
CSCP terminal (pin 3) .
When capacitor voltage reaches approximately 0.68 V the output FET turns off, setting the idle interval to 100 .
Once the protection circuit is activated, it can be reset by turning the power supply off and on again. (See “Setting
the Timer Latch Short Circuit Protector Time Constant.”)
Transient status during normal power-on or momentary drops in supply voltage can cause abnormal operation
in an control IC, leading to damage or degradation of system components. The undervoltage lockout circuit
prevents such abnormal operations by reading the internal reference voltage level and switching the output FET
off, setting the idle interval to 100
System operation is restored when the supply voltage rises back about the undervoltage lockout circuit threshold
voltage.
The overvoltage protection circuit uses an overvoltage comparator (OVP Comp.) to read the output voltage
levels from the DC/DC converter. If the output voltage exceeds the threshold voltage a latch is set, turning off
the main side FET.
Once the protector circuit is activated, it can be reset by switching the power supply off and on again.
CS terminal voltage level
GND
Hi-Z
Output On/Off Setting Functions
and holding the CSCP terminal (pin 3) to “L” level.
Output state
OFF
ON

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