Here is the indicative schematic circuit diagram of the usb charger doctor, drawn by me. Voltage measured at various points, when powered by my lab power supply (dialed to 5.0 Vdc), is also included ...

(usb condom isolates the usb data pins) How does it work? As seen in the circuit diagram below, the circuitry is very simple and the hardware is compact enough to fit inside a matchbox-sized enclosure ...

This file type includes high-resolution graphics and schematics when applicable. The USB Type-C connector specification and the related USB 3.1 and USB Power Delivery (USB PD) specifications ...

The circuit is based around the TP4056 integrated circuit, which handles the charging of a single lithium cell — in this design using supplied power from a USB port.

It is hard to program the serial DB9 port, hence I want to replace it with a usb port instead. attached is the circuit diagram, any suggestions would be very helpful ...