MP158 –SMALL, ENERGY-EFFICIENT, OFF-LINE REGULATOR

MP158 Rev. 1.0

www.MonolithicPower.com

11

10/17/2014

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power supply resumes operation with the

removal of the fault.

Thermal Shutdown (OTP)

To prevent any thermal induced damage, the

MP158

shuts

down

when

the

junction

temperature exceeds 150°C. During the thermal

shutdown

(OTP),

the

VCC

capacitor

is

discharged to 2.4V, and then the internal high

voltage regulator re-charges. MP158 recovers

when junction temperature drops below 120°C

Open-Loop Detection

and a re-start cycle begins. During Soft-Start, the

open loop detection is blanked.

Leading-Edge Blanking

An internal leading-edge blanking (LEB) unit

avoids premature switching pulse termination

due to turn on sipke. Turn on spike caused by

parasitic capacitance and reverse recovery of

freewheeling diode. During the blanking time, the

current comparator is disabled and can not turn

off the external MOSFET. Figure Figure 6 shows

the leading-edge blanking.

350ns

t

Figure 6: Leading-Edge Blanking