AAC242 Datasheet, PDF (5/8 Pages) List of Unclassifed Manufacturers – Current Mode PWM Contoller

Power Management AAC242/243
Oscillator Frequency as a function of Rt and Ct
Dead/delay time verses Ct
Oscillator frequency in KHz
Ct Capacitance in nF
Peak current is set by the internal comparator with a fixed limit of 0.250V. Raising the current sense pin (3) to
0.250V or higher will cause a termination of the output pulse regardless of the error amplifier output. The peak
current is normally determined when the current sense pin exceeds the error amplifier conditioned output. Peak
current is determined by the formula:
I_SENSE(PK) = 0.250V/R_S
In some cases where leading edge switching transients exceed the 100ns blanking, a small RC filter will be required.
RC filter
R
C
Rsense
1 _COMP
2 _FB
3
Isense
4 _R/C
Vref ⁸
Vcc ⁷
6
OUT
GND ⁵
© Copyright 2010- ASIC Advantage, Inc. – AADS00012 / R127B - Preliminary - October 2010 5 / 8