ml4823 Fairchild Semiconductor, ml4823 Datasheet - Page 7

• Manufacturer Part Number: ml4823
• Description: High Frequency Power Supply Controller
• Manufacturer: Fairchild Semiconductor

ML4823
SOFT START AND CURRENT LIMIT
The ML4823 employs two current limits. When the
voltage at I
/SD exceeds the I
REF threshold on I
LIM
LIM
LIM
REF, the outputs are immediately shut off and the cycle is
terminated for the remainder of the oscillator period by
resetting the RS flip flop.
If the output current is rising quickly (usually due to
transformer saturation) such that the voltage on pin 9
reaches 1.4V before the outputs have turned off, a soft
start cycle is initiated. The soft start capacitor is discharged
and outputs are held “off” until the voltage at SS reaches
1V, ensuring a complete soft start cycle. The duty cycle on
start up is limited by limiting the output voltage of the
error amplifier voltage to the voltage at the SS pin.
7
REV. 1.0 10/12/2000