From: Z <en...@hd...> - 2007-12-16 21:54:30
|
Hi again, This time I connected an AC power source to a rectifier bridge, and 2 blue 20 mA LEDs in series (from library) as load. Transient simulation runs propely at 300 mW AC source power, but I get a Jacobian singular at 301 mW. At 250 mW it was ok until I connected an 1 pF capacitor. (actually, it is a placeholder for a varistor) Sometimes the simulation becomes ok, if I change the number of timesteps, or the time interval of the simulation. It is more stable, if I start simulation from 0 msec. If I increase the capacitance to 1 uF, the simulation is stable. According to the diagrams, the LED current becomes stable a little bit below 1 mA. I would like to know, how I could eliminate these Jacobian singulars. I would run the simulation above 300 mW and below 1 uF.. I have a similar circuit with 350 mA leds, 3W power source and capacitors around 1 mF, and there I have the same errors in the region 500..2000 uF. Any help appreciated. Thank You for your reply in advance. Szalai Zoltán |