2008年12月14日 · This contains micrcontroller and some other circuitry also besides SIM300. I intend to use SIM300 charging circuit to charge Li-ion battery. But I need to use the backup battery for all of the circuit and not only SIM300. VCHG is 5V coming from an LM317T, whereas VBAT is 4.2V coming from MC34063A. VBAT is VCC for all the circuit.

Vchg -> this is the voltage measured at battery connection when PWM is ON; To be clear I've checked the source code implementation of both. During CC charge phase the algorithm periodically checks if the Vcell > Vmax=4.2V. If not then Ichg is regulated, so that it is ~1C. If so, then CV mode starts.

2009年3月30日 · What you need is a voltage regulator that has a current-limited output. There are several available from various manufacturers.

Remove Vchg from battery. DO NOT float battery at Vchg even if Ichg is very low. vi Monitor Vbat and when Vbat falls to say Vtopup restart step v, charging at up to C/1 if needed while holding at <= Venough until Ichg again falls to C/1 x K

2011年11月28日 · (d) Vchg = Panel voltage when charging (e) Vdiode = diode forward voltage drop. A "magic" measurement - ie far more can be told from this one reading than may be expected. Place a volt-meter across the diode and measure the voltage.

2016年4月15日 · Find a data sheet for that thing and figure out what Vchg is all about. Find a data sheet for that thing and find out how much current it needs when operating. Most especially the maximum current it needs when the GSM module is transmitting. If it needs more than 100mA, then don't count on using it with USB power.

2016年6月28日 · Those are standard decoupling caps for each VDD, and a couple more for good measure. For some reason the designer has decided to collect them all in a single location in the schematic near VBAT rather than distributing them among the supply pins they are decoupling.

2008年12月14日 · Hello there, In SIM300DZ manual, it is written: 3.5.5 Charger requirements Following is the requirements of charger for SIM300DZ. - Output voltage: 5.0V-5.25V - Charging current limitation: 650mA While using that charger I have seen that it does not use more than 650mA current. So do I still...

These will take a long time to fully charge as Ichg assymptotes to zero as Vbat approaches Vchg. You also need to precheck that cells have voltage above Vabsmin - notionally and often a cell below a certain voltage cannot be recovered and is dangeous to charge. | You can make a CC charger with Vmax = say 4V but that adds complexity.

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