PTVupgrade SmartStart Power Supply Protector

[beyoung1]

PTVupgrade has just released the PTVupgrade SmartStart Power Supply Protector. Development of the SmartStart started largely due to the interest and concerns expressed in the TiVo community about the long-term reliability of the TiVo Series 2 power supply, during the critical start-up phase of dual drive systems.

The 12 volt side of the TiVo Series 2 power supply provides the primary power to the disk drive(s) spindle motor. It is currently rated for 1.16 Amps DC. For all IDE disk drives, starting the disk drive platters spinning and releasing the head actuator from the locked position at start-up draws the most current from the 12 volt supply. Once the drive is spinning at full speed, only 1/3 the amount of power is required to maintain the correct spindle speed.

Problems begin when a second drive is added for additional storage capacity to a system designed for a single hard drive because starting two drives simultaneously can draw as much as 3.5 Amps. A 300% increase in the rated value of the power supply.

This has the potential of causing two problems:

One: Higher heat generation and electronic component stress that can decrease the MTBF (Mean Time between Failure) of the TiVo power supply.

Two: Collapse of the 12V side of TiVo power supply, causing the system not to boot properly.

SmartStart mitigates potential limitations of the TiVo power supply when upgrading with an expansion drive by performing three critical functions for the original DVR disk drive during the startup phase:

One: SmartStart offsets the startup of the original and expansion disk drive in the DVR. During the critical startup period, as much as 250% more current is demanded from the TiVo power supply. This initial current draw is required to start the disk platters spinning. SmartStart ramps power to the original disk drive as it completes its stressful startup phase.

Two: SmartStart sequences both supply voltages to the disk drive, separating the logic and motor power supply power into independent switching groups. Disk drive logic power is enabled first and followed several seconds later by motor power. Voltage sequencing further reduces the current surge to the power supply and results in overall lower startup stress.

Three: SmartStart ramps both logic and motor supply voltage to the disk drive. SmartStart’s solid-state power electronics gradually ramps voltage to the original disk drive and prevents power spikes that can stress the TiVo power supply.

After developing and testing a number of different prototype solutions, I believe I’ve developed a good solution to this problem. The design is based on controller technology from the enterprise computing world. I have also collected quite a bit of data measuring TiVo power supply current draw over time from the Series 2 power supplies. The measurements show that leveraging this controller technology is an excellent approach to solving the startup problem.

In conjunction with PTVupgrade we have completed testing and measurement with a wide range of drives and various TiVo systems. Although we have done extensive testing we could not test all potential configurations from all manufacturers of drives and systems. As the SmartStart product was just released last week, I am interested in hearing feedback from any customers of their experience installing and using the product. I am also happy to answer any questions you may have about the PTVupgrade SmartStart.

A product data sheet with detailed current-draw graphs for single and dual drive TiVo systems with and without the SmartStart installed can be found in the TiVo section on the 9th Tee web site.

http://www.9thtee.com/tivoupgrades.htm#smartstart
http://www.9thtee.com/SmartStart-DS.pdf

--Bryan

[FredThompson]

OK, 3 months and this is the only post about what appears to be a $30 widget. Is this truly a serious concern? How often would the power be cycled?

Outside of an initial startup or power cycling due to drive removal or blackouts, when how often would the power cycle?

In other words, is this a $30 "solution" to a non-problem?

Granted, $30 isn't that much compared to a blown drive or lost content but I wouldn't walk past if it was on the sidewalk.

[mrblack51]

this device is mostly advertised for standalone units which have only one drive caddy. I think it would be an interesting endeavor for someone to develop a copy of this using something like a darlington pair and a 555 timer, then release the specs for all to use.

[FredThompson]

Oh, I didn't think about SA units power cycling. All I run are DTiVos and use more powerful stuff for analog capture.

Don't know you need an IC. It's been almost 20 years since I did any circuit design but I seem to recall you can control the switching of a transistor with a cap/resistor pair. IIRC, the charge graph looked similar to what's in the PDF. Maybe all you need are connectors, wires, 2 resisitors, 2 caps, and 3 transistors...

I've started poking around ePanorama for something like this.

Uh...not that it's my intention to take food out of the mouth of 9th tee. The price is probably very fair considering the market size and construction cost.

[PTVupgrade]

OK guys, here's the gig on SmartStart. The only reason we developed it is because one of our competitors was generating lots of FUD (fear, uncertainty and doubt) as to whether it was actually SAFE to add a 2nd drive to the newer Series2 TiVo units, which do have smaller power supplies.

I argued, fervently, on the AVSforum (look up postings by the username "tivoupgrade") that this was BS; that its totally safe because the 'spike' of starting up two drives is so short in duration, that it just doesn't matter. We lost lots of business because our competitor (weaknees - who also infringed our trademarks and squatted on one of our domain names, ptvupgrades.com) continued to scare people into thinking it wasn't safe, but not to worry, he was working on a product that would 'save the day!'

Meanwhile, he came out with a product, as promised; a dinky mechanical relay that potentially introduces more problems that it solves; it certainly doesn't increase MTBF's - in all likelihood, it reduces them.

Not only does it barely reduce the startup draw, as its designed to do, but it does some weird stuff (take a look at this diagram, if you have any insights, I'm curious as to what you think: http://www.ptvupgrade.com/products/s...Comp-Graph.bmp)

Now, here is the rub; we felt we needed to design something because of the folks that were worried about adding a 2nd drive to these units, and we did so, and we did it as cheaply as possible. You'd be amazed at how much these things cost to manufacture - you probably could build ONE much cheaper than the $30 we sell them for, but you couldn't build 500. And unfortunately, our volumes are big enough that we can't hand build them (that would be unreliable anyway) and they are still expensive to manufacture in the volumes that we get them.

I won't tell you exactly how much we make on these things, but it is very close to nothing, so if you think we are gauging anyone, you are wrong on that...

If you guys want to come up with something better and/or cheaper, that would be great - we'd be all over it, too if we could manufacturer it cheaper and sell it for less, too. Just be careful about copying, as the firm that designed it for us did do some unique things to add-value, and I believe there is some IP there that is subject to some rights. It would be better to start from scratch and come up with something novel to solve the 'problem' at hand...

Cheers,
Lou
PTVupgrade

[FredThompson]

From what I see in the graphs, this really isn't an issue. The power supply would have to be incredibly flaky to not handle the small pull of a hard drive motor starting up.

My hunch is these things are sort of like those so-called mileage boosters for cars that get advertised every so often. They don't really do anything. (Not that you're a snake oil operation, I think the exact opposite.)

Personally, I like your operation a lot. I'm actually ordering more stuff today. Regarding the cost of your device, I'd be surprised if you make any profit at all on those things when you factor int he cost of the money that has to be invested to purchase a manufactured lot.

Having said that, some form of spike dampener wouldn't hurt, just don't know if it's necessary.

Regarding, weaknees, ... well ... I just prefer to do business with you.

Now, if you can figure out how to put a Japanese Maple inside the S2, that would be a welcome addition

[PTVupgrade]

Originally posted by FredThompson
From what I see in the graphs, this really isn't an issue. The power supply would have to be incredibly flaky to not handle the small pull of a hard drive motor starting up.

My hunch is these things are sort of like those so-called mileage boosters for cars that get advertised every so often. They don't really do anything. (Not that you're a snake oil operation, I think the exact opposite.)

Personally, I like your operation a lot. I'm actually ordering more stuff today. Regarding the cost of your device, I'd be surprised if you make any profit at all on those things when you factor int he cost of the money that has to be invested to purchase a manufactured lot.

Having said that, some form of spike dampener wouldn't hurt, just don't know if it's necessary.

Regarding, weaknees, ... well ... I just prefer to do business with you.

Now, if you can figure out how to put a Japanese Maple inside the S2, that would be a welcome addition

Much appreciated... Thx... Yes, its basically an 'insurance policy' for those who are nervous. I don't think it makes a huge difference to have one of these devices. But, it does reduce the draw on the power supply for that brief instance. Some folks want that; so there you have it.

In any case, regarding the 'Japanese Maples...' that's 9thTee you are talking about there, right? We (PTVupgrade) do stay focused on the TiVo stuff, but if we see a market for turning one into a TreeVo, we'll definitely work with 9thTee about it!

Thx,
Lou (PTVupgrade)

[beyoung1]

I would be happy to make the SmartStart schematic available if there is interest in the forum.

The biggest challenge of constructing your own unit based on my design is the main controller can only be purchased in a SMD (Surface Mount) package and requires a custom PCB to allow for a compact design. I’m not saying it can’t be built without a custom PCB it’s just that it would not be much fun to build.

If there is interest we could also make available a kit that you could build your own unit this could include the SmartStart PCB.

Lou is right. No one is making a killing building SmartStart including me. It’s a product that I believe provides long term protection for the power supply on the TiVo Series 2 and directly addresses many of the concerns that have been expressed in the community.

--Bryan

[newbie]

Wouldn't a better (and possibly cheaper solution) to just replace the power supply?

[PTVupgrade]

Originally posted by newbie
Wouldn't a better (and possibly cheaper solution) to just replace the power supply?

Easier said then done... You can't just walk into Fry's and pick up a TiVo replacement power supply that fits in the same box but yields more power.... Also, its dangerous to handle unshielded power supplies once they've been operation - those capacitors carry a charge...

No, this would definitely NOT be easier, even if there were power supplies with that exact specification available...

[mrblack51]

Originally posted by beyoung1
I would be happy to make the SmartStart schematic available if there is interest in the forum.

I would say that there is some interest. If nothing else, it would demystify the claims made, and would make it easier to develop a homebrew version. Thanks for your offer, I look forward to seeing the info.

[Tiros]

Wouldn't a 555 timer and a relay accomplish the same thing? Just switch the power to the 2nd HD a sec or 2 after the first one powers up.

[beyoung1]

The graph on...

http://www.ptvupgrade.com/products/smartstart/

Shows the difference between using a relay vs using a solid-state device to control disk drive power. SmartStart uses a dual solid state MOSFET device to control both the 12V and 5V power independently. Because of this you get a reduced current draw on startup and no startup spike. This is the same approach that is used in the computer industry for hot plug computer devise such as removable Compact PCI boards and disk drives.

There is really little advantage to using a mechanical relay tied to 555 timer. Based on my testing I would argue that you’re better off doing nothing. I believe this is due to the large spike that occurs when the mechanical connection is made in the relay.

--Bryan

[Tiros]

I don't understand that graph. After 8 secs the current drops to zero on the weeknees graph? I was thinking to tie the timer and relay to HD1 so 8 secs after HD1 is powered HD2 would get its power (effective series connection with time delay). The chart looks like both are switched off at 8 secs (current drops to zero).

As for the relay transient, it really should be no different than the transient of hitting a mechanical power switch or just plugging the unit in.

Lets see your schematic.

[beyoung1]

Tiros.

I'm not sure I understand why the Weekneas graph goes to zero when the relay is switched on either. I did spend some time trying to investigate this but came to no conclusion. My first impression was that it was causing the TiVo power supply to completely collapse. I'm not sure that is a correct. Possibly some other folks can take a look at this with better test equipment then I have access to.

With respect to startup delay, you can connect your RC time circuit to the 5 volt supply and achieve the same result.

I am going to have Lou post the SmartStart Schematic on the PTVupgrade site. There is no magic here. SmartStart is based on a dual hot plug controller driving a pair of MOSFETs. This approach is a well established way of starting a disk drive and other devices to prevent power distribution problems.

--Bryan