Timeline for Adapating a single cell Li-ion battery voltage to 3.3V low power application
Current License: CC BY-SA 4.0
7 events
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| Aug 27, 2018 at 23:53 | comment | added | Maple | Yeah, I kinda dropped a ball on those dimensions. Interesting... they don't have soldering profile in the datasheet. I wonder how one can solder BGA without melting the SIP itself. Probably need IR for this, not handheld hot air | |
| Aug 27, 2018 at 23:30 | comment | added | Ale..chenski | @Maple, there are many dozens of other options, theoretically and practically speaking. I just pick the top one. And the TI has 63 TPS82085SIL parts in stock if you want to try... :-) Actually, you must be brutally mistaken, the part is 2.9 x 2.9 mm :-) The TPS82698SIPR is even smaller (2.9 x 2.3), works 3.2 Vout at 3.4 Vin, up to 800 mA, and is in stock for $1.49, digikey.com/product-detail/en/texas-instruments/TPS82698SIPR/… | |
| Aug 27, 2018 at 23:04 | comment | added | Maple | Oh, and I don't know how you do your shopping, but 3x3mm 3A DC-DC with built-in inductor? Damn! And they also have TPSM84 with whopping 35A. How come I never saw those?! Oh, I know how... seem to be permanently out of stock at mouser and digikey :( | |
| Aug 27, 2018 at 0:33 | comment | added | Ale..chenski | @Maple, okay, maybe "battery life" wasn't the best argument to use the 3.0V level of power. 3-V or 3.1V is not the deep discharge, 2.2-2.5 is. The real argument is less complexity of buck switcher topology, and likely more efficient one, and less expensive. I recall there are hybrid switchers that go into LDO mode when the voltage difference is too low (or load too low) for a meaningful PWM duty cycle. Or into "burst mode". Maybe LDO is better, I didn't run the whole design cycle. BTW, LTC3440 shows input range down to 2.7 V for a Li-ion source. | |
| Aug 26, 2018 at 18:19 | comment | added | Maple | "Vbatt = 3.0 V, which will give you maximum battery life". Since we are talking about rechargeable batteries it should be safe to assume that the device will be taken care of and recharged as necessary. In this case the operational time gained by so deep discharge is not worth significant battery lifetime degradation. I agree with @mkeith here, 3.3-3.4V cut-off is much better. | |
| Aug 26, 2018 at 16:47 | history | edited | Ale..chenski | CC BY-SA 4.0 |
added 188 characters in body
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| Aug 26, 2018 at 16:42 | history | answered | Ale..chenski | CC BY-SA 4.0 |