Recent Posts

1

Projects, Designs, and Technical Stuff / Re: Coulomb counter IC for coin cell products.

« Last post by Berni on Today at 05:32:20 am »

It doesn't make sense to use a fuel gauge IC for this.

Those chips are just MCUs that keep measuring the battery current and voltage using an ADC and then plugging that into some fancy algorithm to come up with a SOC in %

Whatever you are powering has to make extensive use of sleep modes to last this long, so just build the coulomb counting into that MCU that runs the show. They consume a pretty predictable amount of current when running and they can time themselves with a timer, multiply the two together and you got the energy used. If you have extra loads being run by the battery you could use the MCUs own ADC to measure the current, but only doing it while you are actually running. When in sleep assume the consumption is 0 by making your sleep mode consume <1uA

Once you get into the last 1/8th of the battery life you can switch to using voltage as a battery indicator (since even fully accurate counting wont be precisely accurate for SOC because not all coin cells are made equal and differ slightly in capacity)

2

EEVblog Specific / Re: EEVblog #1181 - Car ECO OBD2 Fuel Saver SCAM

« Last post by Artz on Today at 05:29:09 am »

Fuel economy is a big selling feature now. If there was something this simple that could make any meaningful impact on fuel economy why wouldn’t the manufacturer do that from factory. None of these fuel saving gizmos ever work.

3

RF, Microwave, Ham Radio / Re: RF 2.4GHZ through Via

« Last post by szoftveres on Today at 05:26:40 am »

Are you sure the TX problem is due to the via?

In general you'll need to absorb the parasitic reactances of the via and pad into a pi-network; i.e. the via would be the series inductor and the pads would be the shunt capacitors; tune everything to 2.4GHz and 50 ohms. This needs to be simulated or modeled for any good results.

4

Microcontrollers / Re: Attiny1606 burning out when connected to a drv8251

« Last post by Faranight on Today at 05:25:45 am »

I'm a bit skeptical. Sounds a bit unusual that the attiny and the reference would need that much current. The reference pin of the DRV8251 is internally connected to a high-impedance amplifier input, so it shouldn't draw any noticeable current (see attachment pic). As for attiny, are you sure that it really needs that much current? Do you have a multimeter where you can measure the amount of current draw from the regulator on the 3V3 rail? A scope would also be helpful to see the voltage ripple on that line.

5

EEVblog Specific / Re: eevBLAB 106 - ChatGPT AI Has Changed EVERYTHING

« Last post by ataradov on Today at 05:24:42 am »

You have one post on this forum. What "again" you are talking about? And why are you bringing up 1 year old topic?

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EEVblog Specific / Re: eevBLAB 106 - ChatGPT AI Has Changed EVERYTHING

« Last post by Artz on Today at 05:21:29 am »

I'll say it again: Google is a dinosaur, and ChatGPT is the meteor.

7

Projects, Designs, and Technical Stuff / Re: Coulomb counter IC for coin cell products.

« Last post by inse on Today at 05:20:19 am »

If the battery monitor is ten times the price of a battery (BQ35100), I doubt it makes sense economically…

8

RF, Microwave, Ham Radio / RF 2.4GHZ through Via

« Last post by 24602 on Today at 05:18:04 am »

Have done a board design with a 2.4ghz module on the bottom of a PCB (placed due to size restrictions of board). The RF receive of the board has been fine but when transmitting the signal strength is basically non existent.

The RF TRX of the board is a castellated edge terminal then sent through a via to the other side of the board goes to a RF switch to either a SMD antenna or SMA connector (Schematic attached)

PCB Top and bottom attached also, I have deleted other components around the area for clarity.


Running RF through a via isn't ideal but because I have to, what is the best way of going about this? What would improve the TX Rf performance of the design?

9

Power/Renewable Energy/EV's / SMPS input filter cut off frequency

« Last post by Faringdon on Today at 05:17:10 am »

Hi...regarding SMPS input filters........

Page 66-77 of Basso Book "switch mode power supplies" covers Input filters for SMPS.
snva538 by ti.com also covers Input filters of SMPS.

snva538
https://www.ti.com/lit/an/snva538/snva538.pdf?ts=1713952246374&ref_url=https%253A%252F%252Fwww.google.com%252F

The "DCM design guide" (A "DCM" is a type of DCDC SMPS module) by VicorPower also covers Input filters for SMPS on pages 11 to 33

DCM design guide
https://www.vicorpower.com/documents/design_guides/DG-DCM-Design-Guide-VICOR.pdf

....Near bottom of page 23 of "DCM design guide" it states, (regarding an input LC filter for an SMPS)....
QUOTE>>>> Select the cut-off frequency below the crossover frequency (20kHz) of the DCM. <<<<UNQUOTE

That is, its saying the the cut-off frequency of the SMPS LC input filter should be below the SMPS's crossover frequency.

Neither Basso, nor ti.com, nor any other reference that i can find make this stipulation. Why do
VicorPower stipulate it?

10

Test Equipment / Re: Siglent SDS3000X HD and upgraded SDS1000X HD

« Last post by Performa01 on Today at 05:15:09 am »

Even if Dave would actually care and create a similar fuss as with Rigol, it would be of no benefit for DSOs above hobbyist level, which I would define with the SDS2000X Plus as an upper limit. Or an SDS2000X HD at most after the latest price drop.

Higher class instruments such as the midrange SDS3000X are for professionals primarily (even though it's still a very affordable X-class instrument). And Professionals just don't base their purchasing decisions on the EEVblog - neither Dave's videos, nor the forum with its rather low S/N ratio...