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ADP2291 Battery Charger Circuit is not working as expected

Harald Kapp

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Nov 17, 2011
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They are not working.
My fault, I beg your pardon. The BAT pin senses the battery voltage and disables charging when no battery (or a battery with too low voltage) is detected :(.

Going back to the table in post #18:
1668683237047.png
On a bipolar transistor IE = IB + IC, but you show 113 mA = 115 mA + 27 mA (ignoring the error in the sign) which is clearly not true.
Next IRS = IE (input currrent to the CS pin should be negligible), but your measurements show 58 mA = 113 mA which is clearly also wrong.
Also VRS = RS × IRS, but your table indicates 80 mV = 0.1 Ω × 58 mA which also is definitely wrong.

Something is completely wrong with your measurements.
 

turgut

Nov 8, 2022
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Yesterday i tried a different thing i want to write about what happened. I connected 2 BD136N transistor as parallel (days ago i tried 2 parallel FZT549) than i started the circuit which in figure.22. Than it works for 10 minutes i think. I got this results,
Vin=6V I=730mA
Vin=7V I=840mA
After that i measured the circuit to how much mV will charge. The battery charged 15mV by circuit in 10 minutes. (i measured battery voltage when i started and when i stoped) It is not i expect but its new. Than i stoped the circuit to connecting to ampermeter to connecting battery. And i started again but didnt work. Now this two BD136N works like other transistors. (FZT549, FZT749, BCX53)
Today i will try new BD136Ns with a 5V relay. I will give the load to relay and transistor will fresher i think.
 

turgut

Nov 8, 2022
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I removed FZT549 to see what will happen if i remove the transistor and did this steps.
-Removed transistor.
-Connected DRV (base) to GND with a 330ohms resistor.
-Connected directly CS (emitter) to BAT (collector).
-And measured the currents like this,
Vin=6V I=496mA
I confused that i removed transistor so what is limitting the current? Why it is not higher than 500mAmps? Why it is not 750 mAmps?
I tried the battery with another battery charger so the battery getting 600mAmps current. It means it is not about battery. Also i tried a new 200mOhms resistor so resistor cant be like battery. I really dont know but im thinking that its about ADP2291 IC.
 
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Harald Kapp

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I could bet your 100 mΩ resistor is not 100 mΩ but higher.
 

turgut

Nov 8, 2022
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I could bet your 100 mΩ resistor is not 100 mΩ but higher.
Im using not just a resistor. Now Im using 200mOhms. A resistor is oldish yes but today i tried with brand new resistor. (I opened package just 2 hours ago.) And the results are same. Also im not using just an ADP2291 IC, im comparating them. And their results are same. So im accept your bet sorry.
The new resistor: 200m Ohms 1% 1W
 
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