POWER SUPPLY IDENTIFICATION IN A 3 WIRE SYSTEM
Original Publication Date: 2002-Aug-13
Included in the Prior Art Database: 2002-Aug-13
Intelligent charging systems benefit from properly utilizing the available energy from its power source. In some cases the system is compatible with several different power sources. In order to properly benefit from the capabilities of different power sources, the charging system must be able to recognize the type of power supply it is connected to. This could be done either mechanically or electrically. While there are some advantages of differentiating power supplies mechanically, the disadvantages far outweigh the advantages when dealing with intelligent charging systems that can accept multiple types of power supplies. Therefore, the effects of using an electrical identification in an intelligent charging system will be investigated. It is not uncommon to use a code resistor for power supply identification. In fact, prior art (US Patent 5,506,490) suggests this can be done using four wires: power supply voltage, power supply feedback, code resistor voltage, and ground. However, there is a potential issue when the intelligent charging system is also a host device for another intelligent charging system that utilizes the same power supply. This invention combines the code resistor and power supply feedback to achieve successful power supply identification using only three wires and also eliminates the issue with two intelligent charging systems utilizing the same power supply.