Reference Designs
How does a usb charger work
Simple Cell Phone Charger Circuit Diagram - 5V from 230V AC
USB phone charger on batteries - MadWizard.org
Portable USB charger circuit diagram | Portable usb charger, Cell phone charger, Battery charger circuit
USB Battery Charging Guide | Maxim Integrated
Safe 3A USB car charger - CircuitLab
USB Battery Charger Circuit
Simple USB battery charger circuit
charger - Building a USB Charging Circuit Using 120VAC - Electrical Engineering Stack Exchange
USB Single Cell LiPoly Charger | Rustic Engineering
Reverse Engineered Schematics
Simple USB Charger Circuit - DIY
Teardown of the mysterious KMS 4-port USB charger
QC 2.0/3.0 USB charger
Portable USB Charger Circuit - Build Electronic Circuits
Portable USB Charger Circuit - Build Electronic Circuits
Power Supply Hub With Battery Charger, Quad-USB & Variable Outputs
Power Supply Module DC 2.5V~5V to 5V 1A Battery Charging Circuit Module/Power
emergency usb charger circuit diagram - The DIY Life
charger - Building a USB Charging Circuit Using 120VAC - Electrical Engineering Stack Exchange
usb charging circuit - CircuitLab
