Hello!slum449.zip
Our R&D Dep. is in the designing process of a power supply for traffic lights.
This PS is supposed to drive a LED disc consisting of 120 LEDs (10 strings,12 LEDs per string).
We have 3 LED discs one of each colour.
Red: 90mA@23.5V
Amber: 120mA@26V
Green :100mA@35V
So, we want a universal PS that, with the help of a microprocessor, can select the appropriate output current controlling Iadj and Pdim pins of TPS92512 IC.
Design Requirements:
- Vin min :42V
- Vout max :36V
- Iout max :120mA
- Switching Freq :300kHz
- Iled ripple p-p :36mA or less
Based on the Design Procedure fount at the correspond Datasheet we have the following values.
- R1=169kohm
- R2=5kohm
- Rrt=406kohm
- RIsense=2.5ohm
- L=230μΗ
But, when I apply these values at PSpice, system’s response is totally wrong.
I don’t know whether this is a calculations or simulation problem.
Any ideas on what is going wrong?
Thank you in advance
Nick
