1. Presented by : GROUP 1 Associates: Ajeet Kumar Pooja Raikar Sangamesha J M Utkarsh Kumar Viresh Mathad

2. Introduction SMPS means Switch Mode Power Supply. They step down voltage by "switching" it on and off, hence their name. Switch Mode Power Supply (SMPS) is a power supply system that helps supply power to computers and other electronic devices in day to day life. It is an electronic power supply that includes a switching regulator to convert electrical power efficiently. SMPS converts AC Voltage to DC voltage. All the computer parts work on DC supply. SMPS supplies DC voltage through connectors on Motherboard and various other devices. In a Personal Computer digital ICs may need 3.3volt supply and the hard disk driver or the floppy driver may need ±5 and ±12 volts supplies.

3. SMPS Consists Of FAN is used to dissipate/reduce the heat generated in SMPS. There are two AC power sockets. One is for AC 220 V input to SMPS and the other is for output AC 220 V to your Monitor/LCD. In some SMPS there is only one socket for AC 220 V input to SMPS. In this case the monitor will take input supply directly from other power source. DC output Connectors for Motherboard are used from SMPS to give different supply voltage required by components like IC’s, hard drive etc. The cable wire colours and their corresponding voltages are to be followed while connecting according to specification.

4. Types of SMPS Switched-mode power supplies can be classified according to the circuit topology and they are 1.Isolated converters 2.Non-isolated converters. Isolated converters All isolated topologies include a transformer, and thus can produce an output of higher or lower voltage than the input by adjusting the turns ratio. Ex: Flyback, ring choke converter, Half bridge and Full bridge etc. Non-isolated converters Non-isolated converters are simplest, with the three basic types using a single inductor for energy storage. Ex: Buck, Boost, Buck-Boost etc.

5. Switching Regulators Switching voltage regulators are heart of SMPS. Switching regulators offer input voltage capability from 2.25V to 60V, switching frequencies up to 4MHz. Switching regulators more complicated as compared to linear regulators in terms of circuitry.

6. Details about SMPS Functionality The switching regulator consists of 1. Input rectifier 2. Inverter 3. Voltage converter 4. Output regulator

7. Switching Regulator Components Input rectifier The AC input from mains is first rectified in the SMPS using a rectifier to convert it into DC. Inverter The inverter converts the rectified DC into AC using a power oscillator. Switching is controlled by a MOSFET amplifier. Converter The converter converts the voltage up or down to the required output level. The output transformer in the block diagram serves this purpose. Output rectifier Since DC output is required, the AC output from the transformer is rectified. The rectified output is then smoothed by a filter consisting of inductors and capacitors.

8. Selection of SMPS

9. Applications of SMPS Used in Personal Computers. Battery Chargers. Consumer Electronics. Video game platforms. Robots. Digital cameras.

10. Advantages and Disadvantages Lower weight. Smaller size. Higher efficiency. Lower power dissipation. Wide ac input voltage range. Reduced costs. Advantages of SMPS over other power supplies are Disadvantage of SMPS are : Greater Complexity involved in the circuit. Electromagnetic interference (EMI).

11. What Is Booting Process ? Booting is the initialization of a computerized system. The system can be a computer or computer appliances. Booting process involves two stages: - Getting hardware Up and running. - Getting the OS and other software Up and running. There are two types Booting : - Warm Booting (Soft) - Cold Booting (Hard)

12. Why Is Booting Required ? Hardware doesn’t know where the operating system resides and how to load it. Need a special program to do this job. E.g. BIOS – Basic Input Output System. BIOS locates the Kernel, loads it into main memory and starts its execution.

13. How Boot Process Occurs? On switching on, the Computer initializes itself by getting proper amount of power supply. Then, it looks for first instruction to execute to start the booting from the BIOS. Instruction stored in BIOS perform POST(Power On Self Test) sequence. In POST it first checks the BIOS chip and test the CMOS. If there is no battery failure in CMOS,then CMOS follows the instructions of BIOS. BIOS instructs CMOS to find the Operating System.

14. CMOS contains all the information about the H/W installations of the computer and BIOS settings as well. CMOS looks for Boot Sequence in order to find the respective OS. Once the OS is initialized, the BIOS copies its file to the memory and transfers the control to OS. After getting control, OS performs memory availability check and then loads the device drivers. Once the drivers are loaded you will come across the Login screen. Thus, the Booting Process. How Boot Process Occurs?

15. Flow Diagram

16. Comparison Of Booting Process

17. UEFI The Unified Extensible Firmware Interface is a specification that defines a software interface between an operating system and platform firmware. UEFI replaces the Basic Input/Output System (BIOS). UEFI can support remote diagnostics and repair of computers, even with no operating system installed.

18. Conclusion Thus ends the lengthy journey that begins with the push of a button and ends with an operating system’s kernel loaded into the memory and executed. The boot loader process is certainly a lot more nuanced and complicated than most realize, and it has both been designed and evolved to work in a fairly- standardized fashion across different platforms and under a variety of operating systems. When working properly, the boot process is a well-oiled machine, but when disaster strikes, it can be a very difficult process to understand and debug.