www.photomacrography.net :: View topic - Full electronic shutter
www.photomacrography.net Forum Index
An online community dedicated to the practices of photomacrography, close-up and macro photography, and photomicrography.
Photomacrography Front Page Amateurmicrography Front Page
Old Forums/Galleries
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Full electronic shutter
Goto page Previous  1, 2
 
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Technical and Studio Photography -- Macro and Close-up
View previous topic :: View next topic  
Author Message
mjkzz



Joined: 01 Jul 2015
Posts: 967
Location: California/Shenzhen

PostPosted: Sat Jun 02, 2018 6:44 pm    Post subject: Reply with quote

mawyatt wrote:
Lou,

Yes, Peter sells them. They also can control your various focus rails, since it has programmable motor and lead screw capability and doesn't require a computer/pad/smartphone to operate Very Happy

http://www.mjkzz.com/product-page/stand-alone-controller-with-remote

The USB-C specification according to WiKi is a maximum of 5 volts for power. Since a typical LiOn cell is 3.7~4 volts, thus a simple USB-C non-switchmode regulator/charger could charge a single cell, but not a dual cell (like Nikon uses). A dual cell LiOn USB-C regulator/charger would require a more complex switchmode topology. My Nikon MH-25a charger is rated at 8.4 volts at 1.2 amps, this is for the Nikon EN-EL15 7 volt LiOn batteries.

Anyway, this is why I asked Peter about it.

Best,


Mike, there are specialized chips for charging Li-Ion batteries. I have used one such chip from Microchip, they have step up (some step down) circuit built-in and they have charging curve built-in so users do not have to worry about it.
_________________
https://www.facebook.com/groups/mjkzzfs/
Back to top
View user's profile Send private message Visit poster's website
mawyatt



Joined: 22 Aug 2013
Posts: 1630
Location: Clearwater

PostPosted: Sat Jun 02, 2018 7:43 pm    Post subject: Reply with quote

mjkzz wrote:
mawyatt wrote:
Lou,

Yes, Peter sells them. They also can control your various focus rails, since it has programmable motor and lead screw capability and doesn't require a computer/pad/smartphone to operate Very Happy

http://www.mjkzz.com/product-page/stand-alone-controller-with-remote

The USB-C specification according to WiKi is a maximum of 5 volts for power. Since a typical LiOn cell is 3.7~4 volts, thus a simple USB-C non-switchmode regulator/charger could charge a single cell, but not a dual cell (like Nikon uses). A dual cell LiOn USB-C regulator/charger would require a more complex switchmode topology. My Nikon MH-25a charger is rated at 8.4 volts at 1.2 amps, this is for the Nikon EN-EL15 7 volt LiOn batteries.

Anyway, this is why I asked Peter about it.

Best,


Mike, there are specialized chips for charging Li-Ion batteries. I have used one such chip from Microchip, they have step up (some step down) circuit built-in and they have charging curve built-in so users do not have to worry about it.


Peter,

If it's a step up converter chip then it must be a switchmode type of some sort, a continuous time regulator chip can only down convert. Switchmode converters can either step up or down as you mentioned. They also can produce considerable switchmode noise which can corrupt sensitive circuits unless extreme care is taken.

Best,
_________________
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike
Back to top
View user's profile Send private message
mjkzz



Joined: 01 Jul 2015
Posts: 967
Location: California/Shenzhen

PostPosted: Sun Jun 03, 2018 1:36 am    Post subject: Reply with quote

Mike,

OK, but I think these charging IC chips are mature enough, the issues you raised are taken care of. Some of the chips are intelligent enough, I suspect they have a micro processor inside.

Regards
Peter
_________________
https://www.facebook.com/groups/mjkzzfs/
Back to top
View user's profile Send private message Visit poster's website
mawyatt



Joined: 22 Aug 2013
Posts: 1630
Location: Clearwater

PostPosted: Sun Jun 03, 2018 5:04 am    Post subject: Reply with quote

Peter,

I meant that the designer of the "USE" of these switchmode chips must be very careful with sensitive circuits, not the actual switchmode chip design. I'm sure these chips are well designed and thought out.

Long ago, we had a very complex sensitive chip that was used in part of a Motorola communications system, they were having "noise" problems and blamed our chip. A colleague went to investigate the problem and when he saw the O-scope traces, he immediately asked if they were using a Charge Pump (a switchmode type chip). They answered yes, he said that's the source of your noise problem, not our chip and then left!!

So the user of these switchmode chips must be careful with sensitive circuits, whereas linear type regulators produce much less noise and easier to apply. Our camera sensors have very low image noise levels, which implies sensitive circuits (amplifiers and ADC), so one must exercise extreme care when designing the camera with switchmode chips.

Best,
_________________
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike
Back to top
View user's profile Send private message
cmagno



Joined: 08 Oct 2012
Posts: 35
Location: Porto, Portugal

PostPosted: Wed Jun 06, 2018 5:05 pm    Post subject: Reply with quote

Amazing results. Congratulations!

Best regards,
Carlos Magno
Back to top
View user's profile Send private message
mjkzz



Joined: 01 Jul 2015
Posts: 967
Location: California/Shenzhen

PostPosted: Thu Jun 07, 2018 8:05 am    Post subject: Reply with quote

cmagno wrote:
Amazing results. Congratulations!

Best regards,
Carlos Magno


Thanks Carlos
_________________
https://www.facebook.com/groups/mjkzzfs/
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Technical and Studio Photography -- Macro and Close-up All times are GMT - 7 Hours
Goto page Previous  1, 2
Page 2 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group