BD7J201HFN-LB (Under Development) BD7J201EFJ-LB
Description of Blocks – continued
2
VIN UVLO
This is the input low voltage protection block.
When the VIN pin voltage becomes VUVLO1 or less, the IC detects VIN UVLO and stops the switching operation.
When the VIN pin voltage becomes VUVLO2 or more, the IC releases VIN UVLO and starts the switching operation.
During tSS from the start of switching operation, the output voltage gradually rises due to the soft start function.
VIN pin voltage
VUVLO2
VUVLO1
0 V
tSS
Setting output voltage
Setting output voltage × 0.9
Output voltage
Switching
ON
ON
Figure 2. VIN UVLO Timing Chart
3
EN OVP
This is the SDX/EN pin voltage over voltage protection block.
When the SDX/EN pin voltage becomes VENOVP1 or more, the IC detects EN OVP and stops the switching operation.
When the SDX/EN pin voltage becomes VENOVP2 or less, the IC releases EN OVP and starts the switching operation.
During tSS from the start of switching operation, the output voltage gradually rises due to the soft start function.
Figure 3. EN OVP Timing Chart
Refer Application Examples:7 Enable OVP Detect Voltage and Enable OVP Release Voltage for the enable control by
the VIN pin.
4
SOFT START
When the SDX/EN pin voltage becomes VEN1 or more and enable status, the comparison voltage in the comparator
block transits slowly 0 V to VINTREF. This operation prevents the IC from rushing current at the rising edge of the output
voltage or overshooting of the output voltage. The soft start time is fixed to tSS in the IC.
5
COMPARATOR
In this block, the IC compares the reference voltage to the REF pin voltage that is the feedback voltage of the SW pin
voltage. This IC is superior to the response for fluctuation in load because it constitutes the feedback loop by the
comparator.
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TSZ22111 • 15 • 001
TSZ02201-0F1F0BZ00020-1-2
08.Jul.2021 Rev.001
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