how to build a standard power bank

Hello guys hope you have all been good, sorry this is coming a bit late, please follow cautiously as we look at how to build a boost converter circuit from 3.7v to 5volts at 1am also called power bank

  Introduction

A power bank is a device that stores up power for later use, in this case we will be building a diy power bank based on DC to DC boost converter IC although we have so many boost converter ICs  but for understanding purpose and at beginner level we will limit it to just one IC. 

  And our design will be based strictly on the IC named (max8815a) from maxim

     Max8815a

This ic is a boost converter IC having 10pins and is capable of boosting voltage from as low as 1.23volts to as high as 5v at 1amp which is very OK to charge our phones even tablets, but it might just charge tablets slowly, it also features the short circuit and thermal shut down mode and lots more, for more information please refer to the data sheet.

    Circuit diagram and explanation

Up there is the circuit diagram for the standard power bank, if you followed the blog you will notice some clock in pins at pin 4 & 8 the pins are for some designated uses but to cut short the long story .

   To operate the chip in normal mode connect pin8 to ground and connect pin4 to power. With this the chip operates in normal mode although there are other configurations for it but this is the configuration for power bank

.

That is the new power bank circuit, please don't mind my circuit diagram.

 The components listed in the previous diagram is same as the one in mine just that the power rating of the inductor must match the output current you are planning on drawing in other not to burn the inductor.

 How the chip works 

The chip works using pwm technique and some switching circuitary inside, it uses a pwm current mode control scheme.and inside the max8815a are two two channel MOSFET one is nchannel the other is pchannel. When the chip is powered the inductor stores power and the nchannel switch then on the pwm next logic level the pchannel switch then the inductor releases its charge and vice versa. That's how it gets to boost the voltage and manages the current using pwm current control schememodes and the output capacitor is used to stabilize the power and reduce the ripple. Although this chip could be operated in two modes

1. Normal mode

2. Fpwm mode
Note: on this blog the normal mode was used .

A blog will soon be posted and selecting capacitors will be strictly talked about both capacitance wise and capacitors voltage level wise.

Feel free to ask any question at the comment interface given below.

 Thank you for following this blog I hope it really helped. Watch out for our next blog post trust me guys its going to be mind blowing.           Stay cool and remain blessed