MB3889 Fujitsu Microelectronics, Inc., MB3889 Datasheet - Page 16

• Manufacturer Part Number: MB3889
• Description: 2-channel Dc/dc Converter Ic With Overcurrent Protection Symmetrical-phase Type
• Manufacturer: Fujitsu Microelectronics, Inc.

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MB3889
(4) Timer-latch overvoltage protection circuit block (OVP)
(5) Protection status output circuit block (PWRGOOD)
When the overvoltage detection comparator (OVP Comp.) provided for each channel detects the DC-DC con-
verter’s output voltage level exceeding its threshold voltage, the timer-latch overvoltage protection circuit actuates
the timer circuit and starts charging the capacitor CSCP connected to the CSCP terminal (pin 11). If the over-
voltage remains applied beyond the predetermined period of time, the circuit sets the latch to turn off the FET
on the main side of each channel while setting the PWRGOOD terminal (pin 12) to the “L” level.
To reset the actuated protection circuit, either the power supply turn off and on again or set the CTL terminal
(pin 6) to the “L” level to lower the VREF terminal (pin 8) voltage to 1.7 V (Min) or less. It can also be reset by
setting both of the CTL1 terminal (pin 9) and CTL2 terminal (pin 10) to the “L” level. (See “3. Setting Detection
of Timer-Latch Overvoltage Protection Circuit” in
The protection status output circuit outputs the “L” level signal to the PWRGOOD terminal (pin 12) when each
protection circuit is actuated.
ABOUT TIMER-LATCH PROTECTION CIRCUIT.)