sg6742ml Fairchild Semiconductor, sg6742ml Datasheet - Page 10

• Manufacturer Part Number: sg6742ml
• Description: Sg6742ml/mr Highly Integrated Green-mode Pwm Controlle
• Manufacturer: Fairchild Semiconductor

© 2008 Fairchild Semiconductor Corporation
SG6742ML/MR • Rev. 1.0.3
Functional Description
Limited Power Control
The FB voltage increases every time the output of the
power supply is shorted or overloaded. If the FB voltage
remains higher than a built-in threshold for longer than
t
turned off, V
When V
controller is totally shut down. V
turn-on threshold voltage of 15.5V through the startup
resistor until PWM output is restarted. This protection
feature continues as long as the overloading condition
persists.
overheating due to overloading conditions. When V
less than 1.05V (V
12ms (t
turned off after 100µs (t
D-OLP
, PWM output is turned off. As PWM output is
D-OTP1
DD
This
goes below the turn-off threshold (~9.5V) the
DD
). If V
begins decreasing.
prevents
RT
RTTH1
is less than 0.7V (V
D-OTP2
), the PWM is turned off after
the
).
DD
(Continued)
power
is charged up to the
RTTH2
supply
), PWM is
from
RT
is
10
Noise Immunity
Noise on the current sense or control signal may cause
significant pulse-width jitter, particularly in continuous-
conduction mode. Slope compensation helps alleviate
this problem. Good placement and layout practices
should be followed. Avoiding long PCB traces and
component leads, locating compensation and filter
components near the SG6742ML/MR, and increasing
the power MOS gate resistance improve performance.
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