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5v USB smartphone Powerbank

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arul27

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I am designing a smartphone powerbank using ic 7805 everything is ok,But my device is showing charging but its not getting charged and later i had heared about D+ and D- pin also should connected logically to get smartphone charge but each mobile companies have diffrent logic how to fix it kindly help me
 

A 7805 voltage regulator needs an input of at least 7V for its output to be 5V. A 7805 is not used in a powerbank.
A powerbank uses the 5V USB for its battery charger circuit then uses a voltage stepup buck converter to boost the 3.2V to 4.2V from its charged Lithium battery cell to produce the 5V output to charge the phone.
 

kindly give me some reference to voltage stepup buck converter
 

I said it wrong. A BUCK converter reduces the voltage, a BOOST converter boosts the voltage.
Look in Google for a DC BOOST converter circuit.
 

each mobile companies have diffrent logic

There will not be any different logics will be used in the smart phones while using USB. It is only about through the D+ & D-
 

How to connect D+ and D- pins to make mobile charge
 

I have designed the voltage bosster and the input is 3 to 3.7v and i got the output as 6 and above but when i connect to the load that is my mobile its lagging and not getting charged kindly help me to fix here i have enclosed my circuit below

 

What produces your 3V to 3.7V input? A dead Lithium rechargeable battery cell? It is 4.2V when fully charged.

The datasheet for the 2N2222A shows that when its collector current is (3V/100 ohms=) about 30mA then its base current should be 3mA for it to turn on completely (saturate) which is a base resistor value of (3V - 0.7V)/3mA= 767 ohms but your base resistors are 100k which is 130 times too high.

The datasheet for the 2N3904 shows that its max allowed current is 200mA and at 100mA it works poorly. It should be a small power transistor like a TIP31.

The inductor must be rated for a high current like maybe 2A or more.

Nothing limits the output voltage. Without a load or when the phone is fully charged then the output voltage will be very high which will kill the 2N3904 and 1uF capacitor and maybe also kill the phone.
 
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