I've bypassed the LDO's this morning and as reported by Greg and others, it makes a large improvement when powering the FifoPi with a 3.3v battery.
Hi Brum
Glad you had success.
I have done this and power with 3v3 but from LT1963. I dont have a battery supply. I am all linear regs.
I realise I probably have left a lot of performance on the table. Ian is out of battery psus but I am not sure I am really wanting to go that route.
Supercaps also interest me but I'm not keen on the little bombs sat in my living room in case of a short!
Glad you had success.
I have done this and power with 3v3 but from LT1963. I dont have a battery supply. I am all linear regs.
I realise I probably have left a lot of performance on the table. Ian is out of battery psus but I am not sure I am really wanting to go that route.
Supercaps also interest me but I'm not keen on the little bombs sat in my living room in case of a short!
It is certainly more convenient to not use batteries! I have one 3.3v battery that I switch on and off using one of Ian's basic relay boards from a previous GB. Based on only needing one 3.3v battery, I think I will stay with this arrangement, rather than buying the battery management board.
Just to make it clear. (for myself). Ian says that it is theoretically best to bypass the regs with a jumper, but if it’s feeded with 3.3v, this will be done automatically. So is theory and practice the same here ? Or ?..
Anyone tried both options ?
Would the dac run on three 3.05v rails? My lt1963 3x 3v3 is coming up low. I shall remedy this but will it work ok for trialling purposes? I guess no harm can be done by trying.
Another one.....in the absence of Ian's battery psu.....do you think this thing is a start?
And how do I make it safe to charge etc?
1pc Super Farad capacitor module 2.7V 500F ultralow resistance 5.4V 250F | eBay
And how do I make it safe to charge etc?
1pc Super Farad capacitor module 2.7V 500F ultralow resistance 5.4V 250F | eBay
Should be fine with a 3.3v pre-reg, as long as it's current limiting, itll just take a while charge em, that's essentially what I use with smaller caps for avcc. Mine takes about 5 seconds to charge a 1.5f supercap.
So if I understand this whole thing.....provide the caps 3v3 to charge. How do I know they are charged? DVM I assume and measure the time it takes for future charges...that way I dont have to dvm test on subsequent charges.?
Do I have them connected to the dac during charging? If out of circuit for charging....on connecting up I guess there quite a spark....I assume this is where the finesse of Ian's psu has been aimed.?
Do I have them connected to the dac during charging? If out of circuit for charging....on connecting up I guess there quite a spark....I assume this is where the finesse of Ian's psu has been aimed.?
I would charge with it disconnected from DAC, then connect after reaches 3.3 or whatever target voltage is.
The thing I've noticed is the reg can get really hot when charging a big ultracap. I have a fan for when I charge the caps, helps keep it reasonably cool.
You can connect a charged cap to a circuit, but have to be really careful. I have been using two posts and a little jumper to make a simple switch. After cap is charged, I install the jumper to connect cap to load.
BTW, in your ebay link, I'd be worried about all the parts on the circuit card, and what they do. Make sure they don't mess up the ultracap "goodness". You really don't want anything be wire between cap and load. My simple switch is a compromise for usability.
The thing I've noticed is the reg can get really hot when charging a big ultracap. I have a fan for when I charge the caps, helps keep it reasonably cool.
You can connect a charged cap to a circuit, but have to be really careful. I have been using two posts and a little jumper to make a simple switch. After cap is charged, I install the jumper to connect cap to load.
BTW, in your ebay link, I'd be worried about all the parts on the circuit card, and what they do. Make sure they don't mess up the ultracap "goodness". You really don't want anything be wire between cap and load. My simple switch is a compromise for usability.