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BQ24030: USB and Solar Charger with Power Path (BQ24030 / BQ2407x vs. BQ24210 or MCP73871)

Sven Grüner
Prodigy 50 points
Part Number: BQ24030
Other Parts Discussed in Thread: BQ24210, , BQ24166

I am designing a sensor node running off a single cell Li-ion battery (1S1P). The battery should be chargeable from a solar panel and USB.

For everything solar the BQ24210 seems to be the go-to IC, because of it's MPPT-like ability to limit the current drawn from the solar panel when it drops beneath a certain threshold. The MCP73871 from Microchip seems to have a similar feature (proudly explained by Adafruit) and used to be my favorite choice because it also implements something like a Power Path, allowing the charger to reduce the charge/discharge cycles with a proper charge termination (so the claim). Whereas a the BQ24210 only charges the battery without knowing how the system load interferes with it. Am I correct so far?

But now I discovered the BQ24030 and the BQ2407x-family with exactly the same claim. Furthermore it reads "The DPPM circuit reduces the charge current when the input current limit causes the system output to fall to the DPPM threshold". Is that not just the same as the MPPT-like behavior of the BQ24210/MCP73871? If yes, what are the disadvantages against the much younger, and apparently more popular BQ24210?

For the BQ2407x this DPPM threshold is 4.3 V, while the DPM threshold is 4.5 V? That is a bit confusing.

And while I lean towards the BQ24030 (because of the dual input) what would be a good setting for this threshold to charge a standard INR18650 with a run-of-the-mill 5...6 V panel? A standard 39k resistor would give me almost 4.5 V, which should be pretty close to the maximum point of power.

  • 0
    TI__Mastermind 21590 points
    Hello Sven,
    There are 2 different modes which should not be confused with each other. VINDPM monitors the input to make sure it doesn't go below a certain threshold by reducing the input current dynamically. VDPPM does something similar for the output so the charge current is reduced if the output voltage falls below a particular threshold. The BQ24030 doesn't have VINDPM but the BQ2407x family has both. For your application, you can use the BQ2407x family along with a schottky diode or smart switch on the input for 2 input sources. Take notice of the OVP setting of the device you select.
  • 0 in reply to Raheem
    Prodigy 50 points

    Hello Sharafadeen,

    thank you for your quick reply and please excuse my late response.

    After pointing out the difference between the input-related DPM and the output-centered DPPM I read up the whole concept in SLUA400, but you acutally summed it up quite well. Though I admittedly have not fully grasped all consequences of one versus the other for my application, my gut is leaning to go with DPM. But still, many years ago also DPPM seemed to be favored for solar charging: https://www.eetimes.com/document.asp?doc_id=1273171# Any idea why the identical Application Report SLUA394 disappeared from the official TI site?

    But to the point of my question. The BQ24210 ist explicitly advertised for solar charging. But essentially it is just a DPM with settable threshold, correct? So am I safe to assume, that generally any charger with DPM (like BQ2407x, BQ24166) will perform just as well with a solar input, even though the word "solar" is not mentioned anywhere near these devices?

  • 0 in reply to Sven Grüner
    TI__Mastermind 21590 points
    Hello Sven,
    That is correct. The advantage of the BQ24210 is that you can adjust the input DPM voltage which you can't do for other chargers. That is why that device is more suitable for different solar panels that you might want to use. The BQ2407x has internally set VINDPM voltage which cannot be adjusted. It is important to note that the VINDPM feature is only active when in either USB100 or USB500 current limit mode for the BQ2407x devices. Do you have a required VINDPM voltage for your application?
  • 0 in reply to Raheem
    Prodigy 50 points
    Great, thank you for for confirming my assumption. Also for pointing out that restriction to the USB-modes, which I had already forgotten again.

    My solar cell delivers 6 V at full radiation. So the fixed 4.5 VinDPM should be a good compromise also for lesser conditions.