UC3849BL-S08-R datasheet(7/10 Pages) UTC

7 / 10 page

UC3849B

LINEAR INTEGRATED CIRCUIT

UNISONIC TECHNOLOGIES CO., LTD

7 of 10

www.unisonic.com.tw

QW-R103-153.A



OPERAT I ON DESCRI PT I ON (Cont .)

Protection Controls

The IC takes on more protection functions such as OVP, OLP and OTP etc. In case of those failure modes for

continual blanking time, the driver is shut down. Driver is reset after failure is eliminated.

OVP

The OVP will shut down the switching of the power MOSFET whenever VDD >VOVP. The OVP event as followed

Fig.3.

Fig.3 OVP case

Fig.4 OLP case

OLP

OLP will shut down driver when VFB> VOLP for continual a blanking time. The OLP event as followed Fig.4.

OTP

OTP will shut down driver when the NTC resistor temperature TJ>T (THR).

PCB Layout Note

Noise

from

the

current

sense

the

control

signal

can

cause

significant

pulse

width

jitter

continuous-conduction mode, and slope compensation helps alleviate these problems. Good placement and layout

practices should be followed. Avoiding long PCB traces and component leads, locating compensation and filter

components near the UC3849B, and increasing the power MOS gate resistance is advised.

UC3849BL-S08-R 데이터시트(PDF) 7 Page - Unisonic Technologies