XC9268 datasheet(13/30 Pages) TOREX

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XC9268

Series

■OPERATIONAL EXPLANATION(Continued)

The current limiting circuit of the XC9268 series monitors the current that flows through the High-side driver transistor and

Low-side driver transistor, and when over-current is detected, the current limiting function activates.

(1) High-side driver Tr. current limiting

The current in the High-side driver Tr. is detected to equivalently monitor the peak value of the coil current. The High-side driver

Tr. current limiting function forcibly turns off the High-side driver Tr. when the peak value of the coil current reaches the High-

side driver current limit value ILIMH.

High-side driver Tr. current limit value ILIMH=1.3A (TYP.)

(2) Low-side driver Tr. current limiting

The current in the Low-side driver Tr. is detected to equivalently monitor the bottom value of the coil current. The Low-side

driver Tr. current limiting function operates when the High-side driver Tr. current limiting value reaches ILIMH. The Low-side driver

Tr. current limiting function prohibits the High-side driver Tr. from turning on in an over-current state where the bottom value of

the coil current is higher than the Low-side driver Tr. current limit value ILIML.

Low side driver Tr. current limit value ILIML=0.9A (TYP.)

The current foldback circuit operates control to lower the switching frequency fOSC. When the over-current state is released,

normal operation resumes.

ILX

VOUT

VLX

ILIMH=1.3A(TYP.)

ILIML=0.9A(TYP.)

Current Limit

XC9268 Datasheet(PDF) 13 Page - Torex Semiconductor