Dilshan R Jayakody’s Web Log

3.3V is now widely used in electronic circuit projects (especially in digital electronics). These days several MCUs, CPUs and Digital interfaces (e.g: USB, Ethernet) uses 3.3V and in this project we developed suitable compact power supply unit for these projects. This project is mainly based on National Semiconductors LM1086-(3.3) power regulator. With the suitable transformer this circuit may capable to deliver 3.3V (during the testing stages we get 3.29V) with 1.5A of maximum current. If you need more current please use LM1085 (3A) or LM1084 (5A) instead of LM1086 (U1). All the circuit diagrams and PCB patters for this project are located in here . To get the maximum performance, replace C2 and C3 with 10MFD/25V tantalum capacitors. Please note that it is necessary to install good heatsink to the LM1086-3.3 (U1) regulator.

Universal Serial Bus (USB) allows peripherals and computers to interconnect using standard protocol and provide plug and play feature to the devices. At the moment there are 2 specifications available for USB they are, USB 1.1 : In this specification data transfer rate is 12Mbps and 1.5Mbps. USB 2.0 : Support data transfer rate up to 480Mbps. Both these specifications support up to 127 devices and support for hot swapping (no need to power down to remove or connect the devices). In USB devices are categorized as a classes and each class represent the functionality that target device can provided to the host device. For example: AUDIO : Audio and related systems HID : Human Interface Devices. (E.g: Keyboard, Mouse, etc) POWER: Devices related with the power such as UPS systems. IrDA: Infrared devices. There are 4 types of transfers take place over USB, Control transfer : Used to configure the bus and devices on the bus. Bulk transfer : Move data asynchronously over USB. Isochron...