This answers one of your questions, yunyun:
Develop ultra capacitor power supply and LiFePO4 battery power supply
Develop ultra capacitor power supply and LiFePO4 battery power supply
Large capacitors are used to filter out low-frequency noise, and small capacitors are used to filter out high-frequency noise. Therefore, the use of UC is to filter out low-frequency noise to compensate for the electrolytic capacitors, which the capacitance is much smaller than UC, only for high-frequency noise. Capacitors are used for filtering, otherwise what can they do?
If it is used as a DC buffer, no super large capacitance is required, and an electrolytic capacitor is generally sufficient. Generally, parallel UC are used in the circuit system to provide instant large current.
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Ian himself said that UcConditioner have a charging current limit of 700ma~1a.
When your cable is longer, you need to consider using a supercapacitor with a larger capacitance value, because the ESR of the supercapacitor with a larger capacitance value will be smaller to reduce the additional resistance caused by the cable.
The calculation formula of the conductor resistance of the wire is: R=ρ×L/S
Among them, ρ is the conductor resistivity, L is the length of the conductor (M), S is the cross-sectional area of the conductor (mm2).
The resistivity of the copper wire is 0.0175 at 20 degrees Celsius.
If copper wire cross-sectional area (mm2) is 1 mm2.
Copper wire resistance=0.0175*0.3M/1mm2=5mOhms
Maxwell BCAP0360 P270 S18 has an ESR of only 2.9 mOhms.
In other words, the 0.3M copper wire caused 5mOhms, which is equivalent to a large increase in resistance for BCAP0360 P270 S18. How can it be ignored?
If the 0.3M copper wire is only one end of the capacitor, considering the positive and negative copper wires, a total increase of 10mOhms.
In other words, if the wire must be used, it is better to use a supercapacitor with a larger capacitance. For example, the ESR of 3000F is only 0.29 mΩ, which can relatively ignore the additional resistance of copper cables.
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@yunyun
You didn't really get the design idea of my LinearPi.
Why I waste my time designing a PSU if I'm happy with a $25 LDO board ?
Ian
Sorry but I don't realize, what is the purpose of powering the Raspberry with a super regulator?
I would assume that the Raspberry is capable to output corrects data although with high jitter, if not so, then the Raspberry is not suitable to provide I2S signals.
But if we assume that the Raspberry is suitable to provide uncorrupted I2S although with large amount of jitter, there is no reason to use a sophisticated power supply to improve the jitter because the FifoPi should do the job reclocking the incoming signals with very low output jitter.
So the questions are:
is the Raspberry suitable to provide uncorrupted I2S without a super regulator?
if so, is the FifoPi capable to improve (or eliminate) the incoming jitter from the Raspberry?
Andrea,
As I understand it, the problem is with common mode noise on the power line and ground. The I2S signal will be superimposed onto the noisy ground.
The raspberry pi also has some switching dc/dc converters that are noisy. An usbridge signature is a better choise because it has only linear regulators on board regulators and will be less noisy.
As I understand it, the problem is with common mode noise on the power line and ground. The I2S signal will be superimposed onto the noisy ground.
The raspberry pi also has some switching dc/dc converters that are noisy. An usbridge signature is a better choise because it has only linear regulators on board regulators and will be less noisy.
Thank yun yun,but I'm not talking about the cable after the UCconditioner,but the one between the power supply and the UCconditioner,
all the interest of the UCconditioner is to be able to place it very close to the load,around 5 CM in the best,in general I like this cable, cheap and good quality Mil Spec 16 AWG Silver Plated Copper Wire Green Cryo Treated - Mil Spec Wire Silver Plated With Teflon Insulation Cryo Treated -
available in several sizes
@ clsidxxl
Thanks of the information of the wire. It looks very good. I'm interested in buying some.
UcConditioner can be looked upon as a kind of passive power supply. To keep the best possible low noise and dynamic performance(such as ultra capacitor or battery), all passive power supplies need connection resistance as low as possible. Silver Plated wire can have even lower resistance and better high frequency response than the pure copper wire with the same size. So it would be a very good option, and the 16 AWG... should be big enough
.
Ian
Thanks of the information of the wire. It looks very good. I'm interested in buying some.
UcConditioner can be looked upon as a kind of passive power supply. To keep the best possible low noise and dynamic performance(such as ultra capacitor or battery), all passive power supplies need connection resistance as low as possible. Silver Plated wire can have even lower resistance and better high frequency response than the pure copper wire with the same size. So it would be a very good option, and the 16 AWG... should be big enough
.Ian
And I think what you mentioned 3A is the peak current. UcConditioner will take care of the dynamic demand current, the rating peak current of the 325F ultra capacitor can go up to 270A, so I don't think there is any problem. LinearPi will take care of the continuous current (less than peak current), also no problem.
Ian
Not really, unless the noise corrupts I2S signals, the noise incoming from the Raspberry can only modulate bck and ws that means higher phase noise/jitter.
The purpose of the FIFO is just to remove this jitter providing a clean I2S.
If this high jitter is reflected to the output there is a problem in the FIFO, that’s not enough decoupled from the incoming signals.
I would compare the input and the output of the FIFO with and without super regulator to understand.
@ clsidxxl
Thanks of the information of the wire. It looks very good. I'm interested in buying some.
UcConditioner can be looked upon as a kind of passive power supply. To keep the best possible low noise and dynamic performance(such as ultra capacitor or battery), all passive power supplies need connection resistance as low as possible. Silver Plated wire can have even lower resistance and better high frequency response than the pure copper wire with the same size. So it would be a very good option, and the 16 AWG... should be big enough
Ian
Ian glad i could help you
,with the 10 AWG it is possible to do a very efficient power cable.
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My problem is also for LinearPi. Since UcConditioner has a charging current limit of 700mA~1A, even LinearPi can output a current exceeding 1A, UcConditioner cannot receive and use it to charge UC. Therefore, I cannot understand why the output current of LinearPi is designed to reach 3A.
LinearPi's output current can reach 3A, which means that it still maintains the best statue to power UcConditioner when outputting 1A current?
@yunyun
Ultra capacitors in UcConditioner are storage components. They don't consume energy. During conditioning stage(Conditioning LED ON), UcConditioner doesn't take additional current from LinearPi (in dynamic only). LinearPi only need to deliver current as much as the load is demand.
UcConditioner only takes current to charge at first time when empty. Even at that time, LinearPi is still enough to power both.
Ian
Ultra capacitors in UcConditioner are storage components. They don't consume energy. During conditioning stage(Conditioning LED ON), UcConditioner doesn't take additional current from LinearPi (in dynamic only). LinearPi only need to deliver current as much as the load is demand.
UcConditioner only takes current to charge at first time when empty. Even at that time, LinearPi is still enough to power both.
Ian