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Datasheet

Datasheet

BM2PXX3F

TSZ02201-0F2F0A200060-1-2

7.Mar.2017.Rev.009

© 2012 ROHM Co., Ltd. All rights reserved.

www.rohm.com

TSZ22111・15・001

(5) Over Current limiter

BM2PXX3F is built in Over Current limiter per cycle. If the SOURCE pin exceeds a certain voltage, switching is

stopped. It is also built in AC voltage compensation function. This is the function which compensates the maximum

power as the AC voltage’s change by increasing over current limiter with time.

Shown in figure-12, 13, and 14.

Figure 12. No AC voltage compensation function

Figure13. built-in AC compensation

voltage

Primary peak current is decided as the formula below.

Primary peak current:

inductance,

Figure 14. Over current limiter voltage

（

6）L.E.B period

When the driver MOSFET is turned ON, surge current occurs at each capacitor component and drive current.

Therefore, because SOURCE pin voltage rises temporarily, the detection errors may occur in the over current limiter

circuit.

To prevent detection errors, DRAIN is switched from high to low and the SOURCE signal is masked for 250 ns by the

on-chip LEB (Leading Edge Blanking) function.