MPQ8632 HIGH EFFICIENCY 18V SYNCHRONOUS STEP-DOWN CONVERTER FAMILY FOR 4A TO 20A
Thermal Shutdown
For other parts except MPQ8632GLE-10:
The MPQ8632 has thermal shutdown. The IC
internally monitors the junction temperature. If
the junction temperature exceeds the threshold
value (minimum 150ºC), the converter shuts off.
This is a non-latch protection. There is about
25ºC hysteresis. Once the junction temperature
drops to about 125ºC, it initiates a soft startup.
Even the FB voltage exceeds 130% of the REF
voltage, these parts enter a non-latch off mode.
Once the FB voltage comes back to the
reasonable value, they will exit this OVP mode
and operate normally again.
UVLO protection
The MPQ8632 has under-voltage lock-out
protection (UVLO). When the VCC voltage
exceeds the UVLO rising threshold voltage, the
MPQ8632 powers up. It shuts off when the VCC
voltage falls below the UVLO falling threshold
voltage. This is non-latch protection.
The MPQ8632 is disabled when the VCC voltage
falls below 3.3 V. If an application requires a
higher UVLO threshold, use the two external
resistors connected to the EN pin as shown in
Figure 9 to adjust the startup input voltage. For
best results, use the enable resistors to set the
input voltage falling threshold (VSTOP) above 3.6 V.
Set the rising threshold (VSTART) to provide
enough hysteresis to account for any input
supply variations.
IN
RUP
EN Comparator
EN
RDOWN
Figure 9—Adjustable UVLO Threshold
MPQ8632 Rev.1.24
8/28/2013
www.MonolithicPower.com
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