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by subudeepak 4027 days ago
Thanks for sharing. I was wondering, why do we need the sleeve ? Can the voltage boosting module be part of the remote itself ? Isn't that what a dc-dc module does ?
5 comments

In case the remainder of the electronics can not work with the low voltage directly, often a boost converter is integrated in the device. Remotes mostly don't: their electronics can run at very low voltage, at the end of the battery life, the range is reduced because the ir led produces less light.
There's no reasons you can't put a voltage boost circuit into a device other than it would be cheaper not to and consumers will blame the batteries, not your device, if you don't. (also, if your device functions fine with low voltage batteries there is no need to.)
> if your device functions fine with low voltage batteries

Probably not a good idea. Really spent batteries tend to leak and damage the device.

Not working makes the owner change the batteries.

Even with a boost converter, it'll still stop working
>There's no reasons you can't put a voltage boost circuit into a device

It will kill rechargeable lithium batteries.

A single cell AA lithium likely already has a 3.7v (IIRC) to 1.5v step down, but also likely has a cut-off voltage to protect the internal cell too.

If it's built-in lithium then you're as likely put in a step-down or a buck-boost to regulate raw lithium cell pack voltages to whatever the device needs internally, but that also needs a self-protection cutoff.

There's also an efficiency loss from the extra circuitry, particularly when the batteries are good enough that there's no benefit yet.
They could add a bypass circuit around their boost converter, which would give virtually 100%[1] efficiency until the booster actually fires up.

Something like the TI TPS61291[1] draws only 15nA in bypass operation, and maybe 85% efficient in boost.

[1] The bypass switch itself will have some resistance, the part below is ~1.2ohm, which might be significant depending on your load.

[2] http://www.ti.com/lit/ds/slvsbx9a/slvsbx9a.pdf

The sleeve is to get access to the other terminal, the booster circuit needs to see both terminals to work.
I understand what you mean. But in my remote, the batteries are not arranged in serial; they are arranged in parallel. That being the case, my remote can see both terminals of a given battery. Hence, I fail to see, as to why the mechanism cannot be implemented as part of such devices..

The same applies to my wall-clock (which uses a single battery)

They can be. And in fact, in plenty of electronic devices they are since operating from a variable supply voltage is not an option so the typical battery powered device uses dc-dc converter like the one in the article only it does not operate on a single cell but on all cells in series. And that works just fine.
> But in my remote, the batteries are not arranged in serial; they are arranged in parallel

Are you sure? That's pretty uncommon. Are the poles oriented in the same direction or opposite ones? Is one set of poles connected to a pair of terminals shared by a single conductor and the other set using two distinct terminals?

Yeah, that's in series.
This question and more on the previous discussion: https://news.ycombinator.com/item?id=9644931
Why not put it in the battery?