MB39A214APFT-G-JNERE1 Datasheet, PDF (18/56 Pages) Fujitsu Component Limited. – 2ch DC/DC converter IC with PFM/ PWM synchronous rectification

MB39A214A
(8) Over Voltage Protection (OVP)
This function stops the output voltage when the output voltage has increased, and protects devices
connected to the output.
1. Using OVP Comp, this function makes a comparison between the voltage which is 1.15 times (Typ) of
the internal reference voltage INTREF1 and INTREF2 (0.7 V), and the feedback voltage for the FB1
pin (pin 4) and the FB2 pin (pin 9).
2. If the feedback voltage mentioned in 1 detects the higher state by 15µs (Typ) or more, the operations
below will be performed.
y Set the RS latch.
y Set the DRVH1 pin (pin 24) and the DRVH2 pin (pin 13) to the “L” level.
y Set the DRVL1 pin (pin 22) and the DRVL2 pin (pin 15) to the “H” level.
These operations fix the high-side FET to the off state and the low-side FET to the on state for both
channels of the DC/DC converter, and stops switching (latch stop).The over-voltage protection state can be
cancelled by setting both the EN1pin (pin 2) and EN2 pin (pin 11) to the “L” level or reducing the VCC
power once until the bias voltage (VB) falls below V_THL of UVLO.
<Timing chart>
VOUT1
FB1
DRVH1
DRVL1
CS1
VOUT2
FB2
DRVH2
DRVL2
CS2
EN1, EN2
VB
Output voltage
setting value
0V
INTREF¯1.15
INTREF¯1.10
INTREF
0V
Output voltage
setting value
0V
INTREF
0V
Standby
UVLO VTHL
Less than 15 µs
15 µs
Cancellation of over-voltage protection
state by EN = "L".
18
DS405-00007-1v0-E