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Datasheet

Datasheet

BD7679G

TSZ02201-0F2F0A200160-1-2

© 2015 ROHM Co., Ltd. All rights reserved.

2015.6.24

Rev.002

www.rohm.com

TSZ22111・15・001

( 4 ) Over Current Limiter and Leading Edge Blanking Period

BD7679G has over current limiter for each switching cycle.

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

Therefore, when the CS pin voltage rises temporarily, the detection errors may occur in the over current limiter circuit. To

prevent detection errors, the OUT pin is switched from low to high and the CS signal is blanked for 250nsec by the LEB

(Leading Edge Blanking) function. This blanking function enables a reduction of CS pin noise filtering in response to noise

that occurs when the OUT pin is switched from low to high.

( 5 ) Output Overload Protection Function (FB OLP Comparator )

Overload Protection Function monitors the load status of secondary output through FB pin and stops the switching of OUT

pin during excessive load. In over load condition, there is no current in photo-coupler because output voltage decreases

(drops) while FB pin voltage rises.

Figure 9, Overload Protection (Self-restart)

( 6 ) COMP Pin External Stop Function

prevent operation errors caused by noise.

Overheating Protection by Posistor

When a posistor is attached to the COMP pin shown Figure-10, the switching operation can be stopped when

overheating occurs.

Figure 10 COMP Pin Overheating Protection Application