It is not working directly. The phone lights up and displays "Not Charging"to use that voltage as a source to recharge your cellphone, you don't need to step it down to 3.7v, unless you want to recharge the battery directly, out of the cellphone itself.
you know that we don't just recharge a li-ion battery as is. the cellphone has the complete and reliable procedure of recharging it's batteries.
instead, the cellphone will receive 5 to 7 volts input voltage through it's connector, so you just connect the 6v lead acid battery using the right connector. be careful with the polarity though. (usually it's positive center)
I did not understand the circuit. Actually I am beginner in electronics. Please tell me what is U1 and U2? And what is the value of IC? Where is the output? resistances are in ohms or Kilo Ohms? Please help me in detail or refer me any other help understanding basic electronics.See the attached.
U1 and R1 thru R3 limit max current to 355mA. (you should use 1/2W for R1 thru R3; 1/4 would work, but it's marginal)
U2 and R4 thru R6 regulate voltage and current during the final stages of charging.
C1 is required. C2 is a lousy simulation of a battery, but you can get an idea of the charge current, and how it decreases as the battery approaches a full charge.
Datasheet for the low-dropout voltage regulator is here:
http://focus.ti.com/docs/prod/folders/print/tlv1117.html
Did you see the attached file? You may have to click on it to blow it up to full size.I did not understand the circuit. Actually I am beginner in electronics. Please tell me what is U1 and U2? And what is the value of IC? Where is the output? resistances are in ohms or Kilo Ohms? Please help me in detail or refer me any other help understanding basic electronics.
This is better circuit. But where is the output of that circuit? And what is the point A which is marked green? And why battery is written on 10mf capacitor?Attached is a similar circuit, but using just one LM317 voltage regulator IC along with support components.
C1 takes care of transient voltages on the input, in case the power supply is more than a few inches away.
U1 is the LM317 regulator IC.
C2 increases the stability of the regulator.
R4 sets the voltage. With no load, the output should be set to 3.7V exactly.
R2 sets the charging current to approximately 320mA.
R5 causes the charging current to decrease as the battery voltage increases. This is necessary for NiCD, NiMH, and other non-lead-acid batteries; this allows them to "top up" at a slow rate of charge.
One glaring omission is the monitoring of the battery temperature.
btw i have a usb 3.5G modem but the battery is soak. i want to replace the battery with this schematic, i think i will use nokia n70 adaptor (5dcV 380mA)Attached is a similar circuit, but using just one LM317 voltage regulator IC along with support components.
C1 takes care of transient voltages on the input, in case the power supply is more than a few inches away.
U1 is the LM317 regulator IC.
C2 increases the stability of the regulator.
R4 sets the voltage. With no load, the output should be set to 3.7V exactly.
R2 sets the charging current to approximately 320mA.
R5 causes the charging current to decrease as the battery voltage increases. This is necessary for NiCD, NiMH, and other non-lead-acid batteries; this allows them to "top up" at a slow rate of charge.
One glaring omission is the monitoring of the battery temperature.
the batt spec is
Li polimer battery
3.7VDC 380mA
max Voltage 4.2V