Author Topic: LTspice help - transformerless power supply simulation  (Read 5735 times)

0 Members and 1 Guest are viewing this topic.

Offline RicardoATB

  • Newbie
  • Posts: 3
    • RicardoATB DIY Electronic Projects
LTspice help - transformerless power supply simulation
« on: February 08, 2011, 08:48:07 pm »
Hi!

I'm new to LTspice simulations and I would like to construct the following "Capacitive Transformerless Power Supply - App. Note here", but when I run the simulation, I get on net1 the same voltage of V1 and not something like 5 VDC. What am I doing wrong?




Thanks in advance and Long Live David Jones
 

Offline RicardoATB

  • Newbie
  • Posts: 3
    • RicardoATB DIY Electronic Projects
Re: LTspice help - transformerless power supply simulation
« Reply #1 on: February 08, 2011, 08:57:38 pm »
Here follows my LTspice file.
 

alm

  • Guest
Re: LTspice help - transformerless power supply simulation
« Reply #2 on: February 08, 2011, 09:24:32 pm »
If you move the ground node to the same location as in the appnote, or plot V(net1) - V(n003), you'll see the results you'd expect: the zener voltage minus the drop over D2.

If you want to build this, you must consider the whole circuit as dangerous mains, since the caps provide no galvanic isolation, and are probably not rated for line filters (X/Y), so they may be destroyed (or fail shorted) by transients.
 

Offline RicardoATB

  • Newbie
  • Posts: 3
    • RicardoATB DIY Electronic Projects
Re: LTspice help - transformerless power supply simulation
« Reply #3 on: February 08, 2011, 09:58:39 pm »
Thank you very much alm! It worked!

Thank you too for warning me about the risks, as says the Microchip Application Note, I'll use a fuse and other security considerations when I build it.

 

Offline Zero999

  • Super Contributor
  • ***
  • Posts: 13308
  • Country: gb
  • 0999
Re: LTspice help - transformerless power supply simulation
« Reply #4 on: February 10, 2011, 06:10:07 pm »
There needs to be a bleeder resistor (about 1M) across C1 to prevent someone from getting a shock when the plug is removed.

What's the supply voltage? LTSpice uses the peak voltage so 110V is only equivalent to 78V RMS, you need to enter 155.6V for 110VAC.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf