AAC242 Datasheet, PDF (6/8 Pages) List of Unclassifed Manufacturers – Current Mode PWM Contoller

Power Management AAC242/243
In cases where duty cycle exceeds 50% slope compensation is required. This can be implemented by adding a buffer
transistor to the oscillator circuit and using a resistive summing circuit to provide the ramp necessary for slope
compensation.
Slope compensation
Rt
R
Rsense
2N3904
Rslope
C
1 _COMP
2
FB
3 _Isense
4 _R/C
Ct
Vref ⁸
7
Vcc
OUT ⁶
GND ⁵
Shut down circuits depend on the desired function. A transistor can be used to allow control on and off of the PWM
or an SCR can be used to latch off the PWM.
Shutdown circuits
100K
shutdown
1
COMP
2 _FB
3 _Isense
4 _R/C
2N3904
8
Vref
Vcc ⁷
OUT ⁶
GND ⁵
100K
shutdown
1
2
3
4
2N3904
COMP
FB
Isense
R/C
8
Vref
Vcc ⁷
OUT ⁶
GND ⁵
© Copyright 2010- ASIC Advantage, Inc. – AADS00012 / R127B - Preliminary - October 2010 6 / 8