Designing a Lipo Fast Charger

Project Info

Case

The task was to design a power bank that could be used to power small electronic devices via a USB port. It was also supposed to charge 10,000 mAh batteries. The original request was developing several boards each working with a different input voltage. The input voltages were supplied with small solar PV panels.

Requirements

  1. The circuit board was to have capabilities to charge any device very fast like the adaptive fast charging from Samsung as well as fast powering for the output.
  2. The PCB was to have the followings:
    1. 2 x USB Connections
    2. Battery Connect Spots (+) (-)
    3. Power Source Connect Spots (+) (-)
    4. LED Lights Showing the charge Level of the Battery
    5. Fast Charging Capabilities [VERY IMPORTANT]
    6. LED Flash Light as an indicator for connectivity to the solar panel
    7. Lipo batteries as the backup batteries
    8. Safety measures for fast charging
    9. The input voltages that were used to power each board included the followings:
  •  5.8 Watts / 5 Volts size [Rectangular shape – 230mm x 130mm]
  • 3.5 Watts / 3.2Volts size [Rectangular shape – 140mm x 130mm]
  • 1.75 Watts / 1.6Volts size [Rectangular shape – 80mm x 130mm]

Solution

While the original request was making several boards for different inputs, the client later accepted designing a single board taking different voltage inputs. The work was done and it took about two months to get the design. Other than the main functionality of the board, some of the other features of the design included the followings:

  1. Four LEDs were used for showing the charging Level of the battery from 0-100 with 25% steps.
  2. One LED on the corner was used to show that the solar panel was providing electricity to the charger.
  3. Stable output voltage
Description

The final design was submitted to the client and it was subsequently prototyped. The final prototype was according to the client’s expectations. The whole work including the prototyping took about two months to get completed.

Client:
Ana Davis
Date:
August 5, 2018
Location:
CA, US
Category:
Electrical and Electronic Engineering