How To Build Power Bank With Transistor Without Boost Integrated Circuit (See Details)

This circuit above is a boost converter (step up converter) is a DC to DC power supply that steps up voltage while stepping down current from its input .It is a class of switched-mode power supply (SMPS) containing atleast two semiconductor ( a diode and transistor) and at least one energy storage element .

The input power usually come from DC power such as DC baterry,DC generator,DC solar panel.But in this project ,we are going to use 3.7vdc as an input voltage supply.

Component Needed For This Circuit

=>capacitor

=>Inductor

=>Transistor

=>Scotty diode

=>DC battery.

Operation of the circuit diagram

Resistor R2,R1 and capacitor C2,C1 are used in this circuit to build an a stable multivibrator.

Four or or six 3.7vdc battery are connected in parallel.when 3.7vdc battery is connected to the input of the circuit,current flowing through the circuit.

The switching frequency (fs) from the output of the output of the astabe multivibrator is connected to the base of the transistor (Q3) for ON state(high) and OFF state(low).

When the switch(Q3) is closed,current flows through the inductor(L1) in clockwise direction and the inductor(L1) stores some energy by generating a magnetic field.

When the switch (Q3) is opened ,current will be reduced as impedance is higher .The magnetic field previously created will be destroyed to maintain the current towards the load.

If the switch(Q3) is cycle fast enough,the inductor (L1) will always see a voltage greater than that of input sources.

The blocking diode (D2) prevents the capacitor(c3) from discharging through the switch (Q3).The switch most of course be opened again fast enough to prevent the capacitor (c3) from discharging too much.

While the zener diode (D1) give the constant output voltage of 5.1vdc which is sufficient to charge mobile phone.

Circuit descriptions

=>input voltage is 3.7vdc

=>output voltage is 5.1vdc.

=>cycle duty: Vin/Vout

=>power (watt): Vin-Vout *