aussiepoof
New Member
Hi folks,
So I have to admit that while I'm pretty good in the digital world, I'm really not so hot when it comes to the analog thang!
I have an idea to digitally control the output of a NatSemi simple switcher by inserting an digital pot driving an opamp into the feedback loop of the switcher. The result would be a digitally-controlled switchmode power supply
I have used a similar circuit to successfully control an LM317... great except it has the standard issue with being a linear regulator in that it dissipates too much energy as heat. The digital pot has a 0-5v swing, so I amplify that with an opamp to create a 0-14v swing in the adjust leg of the LM317.
So... is this even possible with a switchmode controller? Are there any potential "gotchas" when it comes to inserting a similar kind of circuit into the control loop? I have done some extensive reading and know that switchmode supplies are easy to tip into unstable feedback states.
Here's a link to the NatSemi site for the LM2595:
**broken link removed**
Thanks in advance for any ideas or links!
Regards,
Paul
So I have to admit that while I'm pretty good in the digital world, I'm really not so hot when it comes to the analog thang!
I have an idea to digitally control the output of a NatSemi simple switcher by inserting an digital pot driving an opamp into the feedback loop of the switcher. The result would be a digitally-controlled switchmode power supply
I have used a similar circuit to successfully control an LM317... great except it has the standard issue with being a linear regulator in that it dissipates too much energy as heat. The digital pot has a 0-5v swing, so I amplify that with an opamp to create a 0-14v swing in the adjust leg of the LM317.
So... is this even possible with a switchmode controller? Are there any potential "gotchas" when it comes to inserting a similar kind of circuit into the control loop? I have done some extensive reading and know that switchmode supplies are easy to tip into unstable feedback states.
Here's a link to the NatSemi site for the LM2595:
**broken link removed**
Thanks in advance for any ideas or links!
Regards,
Paul