TPS61299: Single alkaline battery application - draining the most from the battery.

Greg Phillips

Part Number: TPS61299
Other Parts Discussed in Thread: TPS61200

Tool/software:

The data sheet says the chip has an "input operating voltage down to 150mV with signal Vin > 0.7V".

If an application starts with a single AA/AAA battery with voltage over 0.7V (and Vout is set to 3.0V), would it be possible to have a circuit that drains this battery to the 150mV level? I assume that Vout would have to be used to hold Vin and EN above threshold levels somehow. I think I know how I could do that, but it would be great to see some recommended way of doing it.

In general it would be great to have more and varied application circuits (PS it is a great chip for powering a circuit off a SINGLE lemon...)

6 months ago

0 Nini Zhong 6 months ago

TI__Genius 13205 points

Hi Greg,

You could refer to this app note for the application, which thoroughly described the way to design it.

0 Nini Zhong 5 months ago in reply to Nini Zhong

TI__Genius 13205 points

This one:Ultra-low Voltage (150 mV) Start-up Design Based on TPS61299

0 Greg Phillips 5 months ago in reply to Nini Zhong

Prodigy 25 points

Thank you, yes I have seen that application note. It might be my lack of understanding, but I was puzzled by one aspect of that application note. It talks about Vin = 0.7V where is that coming from if the source only generates 150mV?

I still feel there is an opportunity to have simple "cook book" examples of how this chip can be used. Here are some suggestions:

1. A circuit to show how a single AA/AAA battery can power a circuit even though the battery voltage drops below 0.7V

2. A circuit that uses two AA/AAA batteries - but they are NOT in series. The circuit drains the weakest battery first

3. For a bit of fun, a circuit that shows how to run a microprocessor (or flash a Led) from a single lemon

In the old days, data books were full of application ideas (eg. the old National Semiconductor data and applications books)

0 Nini Zhong 5 months ago in reply to Greg Phillips

TI__Genius 13205 points

Actually VIN is power individually, and must be higher than 0.7V. It should be powered independently ..

0 Greg Phillips 5 months ago in reply to Nini Zhong

Prodigy 25 points

Anyway, just suggesting more and varied application circuits would be useful. In the mean time, I will give something like the following a try -

0 Nini Zhong 5 months ago in reply to Greg Phillips

TI__Genius 13205 points

Hi Philip, anyway Vin should be powered independently and this schematic doesn't work.

If the PVIN is extremely low, you could use TPS61200.

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TPS61299: Single alkaline battery application - draining the most from the battery.