Why have a computer if you don't make it *compute* for you?
If your simulator will not report the current in the TL431, then put a 0.0001 Ohm resistor in series and order the simulator to report the current in the resistor.
With the image you give us, it is "possible" to figure the TL431 current but I need all my fingers and toes. X1 is fed by Q2, D5, and R9. (C3 should not pass DC.) D5 current is "n" instead of "u" so is very-very small. So add Q2 current to R9 current.
It looks to me like 0.9mA which does not meet your stated requirement.
WHY is R9 "10k"?? It has NO function except to feed TL431. Many of the specs for TL431 are taken at 10mA. Your load is 400mA, so you can spare 10mA. But say 5mA plus Q2 current. There is 2.5V across R9. We want 5mA. 2.5V/5mA is 500 Ohms. 330, 470, 680, whatever is convenient.
Attachments
TL431 is adjustable in voltage, where a reference IC like REF01 or REF 02 is usually a fixed, trimmed voltage with very no or slight adjustability. Reference ICs also often have a current limit of 20mA or less, where 431 can do a bit more current. Reference ICs may also have a better noise specification as well.
Hello. I really like to build this,
1.please help with the component value. I cannot understand the resistor and capacitor value.
2. How to set the output voltage to 12 volt?
Please help me. Thank you so much. Doni
