Ap3591, Application information – Diodes AP3591 User Manual
Page 14
AP3591
Document number: DS36906 Rev.
1 - 2
14 of 18
March 2014
© Diodes Incorporated
AP3591
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A Product Line of
Diodes Incorporated
Application Information
(Cont.)
The AP3591 provides full-time over voltage protection whenever soft-start completes or not. The typical OVP threshold is 125% of the internal
reference voltage V
REF
. The AP3591 provides latched OVP and can only be released by VDD or EN/DEM power-on reset. There is 33µs delay
built into the over voltage protection circuit to prevent false transitions.
Figure 4. Over Voltage Protection
12. Thermal Shutdown
If the junction temperature of the device reaches the thermal shutdown limit of +160ºC, the AP3591 shuts itself off. Both UGATE and LGATE are
driven low, turning off both MOSFETs. The output is discharged with the internal 20
Ω transistor. When the junction temperature cools down to the
required level (+140°C nominal), the device initiates soft-start as during a normal power-up cycle.
V
OUT
1V/div
V
LGATE
5V/div
Time 100µs/div
V
UGATE
20V/div