UltraCap™ LPS-1 launch thread!

[JohnSwenson]

Is it ok to leave it connected to a microRendu and on all the time? Will this reduce the life of the LPS-1?

 

Does the switching between capacitor banks cause any audible clicking sound?

 

What is the switching frequency between banks?

 

Will this stop any leakage current that may be coming from a router connected via USB to a microRendu if the mR is powered by a LPS-1?

 

Thanks

 

The LPS-1 is designed to be left on 24-7.

 

The bank switching is done with transistors so there is no noise.

 

The time between bank switching depends on the out current. For 1A it switches about every 4 seconds. For low current output like a REGEN it is a couple minutes.

 

On your last question I am not sure what you are asking, the USB on the microRendu is the OUTPUT not the input. If you mean the Ethernet jack, then yes, the MicroRendu is galvanically isolated from the Ethernet cable, and the LPS-1 powering the microRendu prevents any leakage current through the power connection.

 

John S.

[JohnSwenson]

John, what are the orange colored things on the circuit board?

 

There aren't any orange colored components so you must be referring to the heatsink areas. The components that generate some heat (switch transistors, linear regulators etc) are soldered to small rectangles of copper which act as heatsinks. To improve heat flow I removed the soldermask over those areas. The surface you are actually seeing is gold plating over the copper so it won't corrode and loose thermal conductivity.

 

John S.

[JohnSwenson]

On further thinking on what John just said - the LPS1 switches every 4 seconds when running at its max of 1A, this means it switches (or the capacitor cycles) 7.8 million times per year! Or say 23.7 million cycles during the warranted 3 years.

 

Are ultra-capacitors that robust to run 24/7 for years on end? I thought they only had a few million cycles in them.

 

Very good question. I asked the technical reps from the cap company we are using that exact question. They said the lifetime is actually not determined by the number of cycles but by the voltage and temperature. At the voltage we are using and the actual measured temperature of the caps in the case it comes out to over 50 years of lifetime. I think that is not going to be much of a problem for anyone.

 

The rep said the number of cycles is just a quick way to get some idea of how hot the caps are going to get. If you are using lots of deep cycle charge and discharge cycles the caps will get pretty hot. We are actually not charging and discharging them very much each cycle, so the temperature does not get as high.

 

Strangely enough the only time the caps actually get hot is when you unplug it. There is a circuit that fully discharges the caps when it powers down (explaining why you need that is long and complicated), THAT is a full deep discharge and does heat them up a fair amount (but still well within the ratings). The initial charge rate when you turn it on is a little lower than normal so it won't heat them up as much.

 

John S.

[JohnSwenson]

I wonder if there are any reallife measurements available of the LPS-1 regards, ripple, noisefloor ?

 

The noise from the LPS-1 is very low, exactly how low I have not been able to measure. It is below the capabilities of my existing setup to measure. The problem seems to be environmental noise pickup of the cable going from PS to load. I'm going to have to build a special test fixture that plugs directly into the LPS-1 has the load and a very low noise amplifier to drive the test equipment, this should probably measure it.

 

The hard test is going to be the impedance vs frequency graph, I have to build a whole new test setup to measure that.

 

John S.

[JohnSwenson]

Hi John

Somehow I think you are going to have to build a VERY LNA to obtain meaningful measurements, or see proper waveforms with this PSU ! You may have to turn off all the lights and other stuff too !!!

Kind Regards

Alex

Yep, lights are a big issue, whenever I am doing sensitive measurements I have to turn off the lights in the lab. I've been trying to find a lighting system that drastically reduces emissions but it has been a difficult task.

 

John S.

[JohnSwenson]

The answer should be obvious to you --- an ultra cap powered LED lighting system [emoji6]

 

I was looking at a JS-2 powered LED system, but I can't get the raw led I want.

 

John S.

[JohnSwenson]

Alex:

 

"Solid red means the LPS-1 is not outputting any voltage. Unplug the AC>DC supply from the input, wait until the red light goes off completely, then plug the charging supply back in and wait 75 seconds for restart."

 

it only happens if/when the LPS-1 (or its feeding supply) has an "hiccup", not if/when I turn off the device being powered by the LPS-1, right?

 

The LPS-1 will withstand a 4 second disruption to the feed power, so short power interruptions will be unnoticed. If the power is interrupted for longer than 4 seconds the output shuts off, the light turns RED and then goes off completely 7 to 10 seconds later. During that time when the light is RED it is discharging the capacitor banks. If the feed power is resumed while the light is RED the cap strings will sill have some charge. The system is designed so this should work, but there is a very slight chance that it won't start up again if the caps are not discharged. This is extremely rare. If it ever does happen, just unplug, wait until the light goes off, then plug in again.

 

If the power interruption was caused by you unplugging it wait until the RED light goes out before plugging back in.

 

If the interruption was caused by your AC line it will come back on when the line voltage returns.

 

Whether the load is connected or not makes no difference to this.

 

There are two "error conditions": over current, and feeder voltage not sufficient. When an over current happens the output shuts off, the light blinks red 5 times, then goes to normal to check again (light goes green) if the over current still exists it goes back to blinking and repeats until the over current condition goes away.

 

The other condition is if the feed supply cannot maintain sufficient voltage to meet the current requirements of the charging circuit. When this happens the output shuts off and the light blinks RED, the LPS-1 stays in this mode until you unplug it. At this point you should plug in a different supply that can supply the required current. This situation may not happen right away, the full current demand may not happen until the light goes green.

 

So summary of error conditions:

Flashing RED with short greens: over current or short. Goes back to green when over current load or short is removed.

Continuous flashing RED: feed supply doesn't cut it. Unplug supply, wait until light goes out, plug in new supply.

 

John S.

[JohnSwenson]

I have doubts about that guess, but JS or superdad should answer. The fact that the input current varies with Vin indicates more at play than simply voltage.

 

The raw voltage from the input jack goes two places, a switching boost regulator, this takes whatever the input voltage is to a fixed higher voltage. The other location is a linear regulator for the control circuits (FPGA, opto isolators etc)

 

The boost circuit pulls a constant POWER, so the input current will be lower for higher input voltage. This circuit doesn't have to work as hard with higher input voltage (it has to boost less).

 

The linear regulator gets warmer as the input voltage increases.

 

These two are the ONLY parts of the circuit that have any dependency on the input voltage.

 

I personally run mine at 9V to even these two out.

 

BUT please note that all the circuits are designed to work very well at ANY of the input voltages. It makes no difference to the output, the SQ will be exactly the same, all the parts are running well below their rated temperatures no matter what input voltage, so longevity of the device will not vary.

 

PLEASE don't get wigged out over choosing the "optimal input voltage" use whatever you have that works. If you already have multiple voltages on hand or are buying something specific for the purpose that costs the same for the different input voltage/current combinations, then go for 9V. If your choices have different costs then go for the cheapest (or nicest looking or whatever criteria you want to use) as long as it meets the voltage/current requirements.

 

John S.

[JohnSwenson]

Alex,

 

I've been thinking about getting a galvanic isolation device for a while. But, I've concluded that, unless I'm missing something (entirely possible if not likely!) my Regen and Paul Pang USB V.2 card together already do this.

 

Uptone's Regen website says, "The USB REGEN's secondary function is that it disconnects the computer's noisy 5 volt bus power coming down the USB cable, and provides clean 5VBUS on its output--for DACs that need it...." To me, that sounds like the 5V lines going into my DAC are isolated from the computer USB power. No use of the term "galvanic isolation" on the website, but it sure sounds like that's what is happening with respect to 5V bus.

 

As for the digital data, the Paul Pang USB card has a "Hand made silver wire audio grade digital output transformer for TCXO." Pang's website is not crystal clear, but I read this to mean that the USB data lines to my DAC are effectively isolated from the computer USB bus.

 

I would appreciate your (and/or) fellow forum member's) take on this.

 

Rich

 

That transformer is just on the clock, NOT the USB output. Leakage loops from the computer power supply will go right through the USB cable to your DAC.

 

The 5V line being broken is not what matters, it is the ground connection where the leakage loops go through, either the ground wire or the shield.

 

If you want to maintain the advantage of the PPA card your only method right now is to use one of the optical PCIE extension products and power the downstream side from an LPS-1.

 

Another way to do it is put an Intona after the PPA, then into a REGEN powered from an LPS-1. It will sound marvelous, but you are NOT using the advantage you get from the PPA card that way.

 

John S.