Design And Construction Of A Switch Mode Power Supply
The design and construction of a switch-mode power supply involve meticulous planning, precise component selection, and strategic circuit configuration. This process encompasses determining the required output voltage and current, selecting an appropriate switching frequency, choosing suitable semiconductor devices such as MOSFETs or IGBTs, designing the control circuitry using integrated circuits like PWM controllers, and incorporating essential safety features like overcurrent protection and thermal shutdown. Furthermore, optimizing the layout and thermal management of the power supply PCB are critical for efficiency and reliability. A comprehensive understanding of power electronics, circuit theory, and electromagnetic compatibility is essential for successful implementation. How can one ensure the reliability and efficiency of a switch-mode power supply design while meeting stringent safety and performance requirements?
This work is on switched-mode power supply (SMPS) which is an electronic circuit that converts power using switching devices that are turned on and off at high frequencies, and storage components such as inductors or capacitors to supply power when the switching device is in its non-conduction state. The circuit was built around TNY267 switching regulator which performs the functions of the PWM generator, MOSFET chopper switch, error amp, and control circuit.
At end of this work a switching power supplies was built which have high efficiency and durable which is fit to be used in a variety of electronic equipment, including computers and other sensitive equipment requiring stable and efficient power supply.
TABLE OF CONTENTS
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWLEDGEMENT
ABSTRACT
TABLE OF CONTENT
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
1.2 PROBLEM STATEMENT
1.3 AIM/OBJECTIVE OF THE PROJECT
1.4 SIGNIFICANCE OF THE PROJECT
1.5 SCOPE OF THE PROJECT
CHAPTER TWO
LITERATURE REVIEW
2.0 LITERATURE REVIEW
2.1 REVIEW POWER SUPPLY
2.2 REVIEW OF POWER SUPPLY CHARACTERISTICS
2.3 REVIEW OF GENERAL APPLICATION OF POWER SUPPLY APPLICATIONS
2.4 REVIEW OF TYPES OF POWER SUPPLY
2.5 TYPES OF SWITCH MODE POWER SUPPLY
2.6 APPLICATION OF SWITCH MODE POWER SUPPLY
2.7 ADVANTAGES AND DISADVANTAGES OF SWITCH MODE POWER SUPPLY
CHAPTER THREE
3.0 METHODOLOGY
3.1 BLOCK DIAGRAM OF THE SYSTEM
3.2 CIRCUIT DIAGRAM
3.3 CIRCUIT DESCRIPTION
4.0 RESULT ANALYSIS
4.1 CONSTRUCTION PROCEDURE AND TESTING
4.2 ASSEMBLING OF SECTIONS
4.3 CONSRUCTION OF THE CASING
4.4 TESTING
4.5 INSTALLATION OF THE COMPLETED DESIGN
CHAPTER FIVE
5.0 CONCLUSION AND RECOMMENDATION
5.1 CONCLUSIONS
5.2 RECOMMENDATION
REFERENCES
1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
A power supply is an essential part of every electronic device. It converts an AC power line voltage to a steady state DC output voltage as required by all electronic circuits. Power supplies can be categorized into two types: linear and Switch Mode.
Linear power consists of a transformer, rectifier, and filtering and regulator circuits. The rectifiers are used to convert 50/60Hz AC voltage to a pulsating DC. The filters are used to convert the pulsating DC to a smooth voltage. Finally, the voltage regulators are used to produce a constant output voltage, irrespective of the variations in the ac line voltage or by the circuit loadings. The output voltage is sampled by an error amplifier block which compares it with a reference signal and generates an error signal on the basis of comparison [3]. The error signal is applied to a series pass element which alters its resistance accordingly and thus regulates the output voltage. Hence, the series pass element absorbs any changes in the input voltage and any dynamic changes in the output voltage due to the load changes, within its designed tolerance band [1]. The size of the components, such as the transformers and output filters, are very bulky in these supplies. Linear power supplies are not suitable for smaller modern electronics system because of their high power loss, low power density and bulky size.
The SMPS converts the available unregulated AC or DC input to a regulated DC output. The input is taken from the AC mains and then rectified, filtered and fed to a high frequency DC-DC converter. SMPS can be operated within the kHz to MHz frequency range. The increased switching frequencies cause a decrease in the size of the energy storage elements, such as the capacitors, inductors and transformers, in an almost linear manner [3].
This work is aimed at building a Switch Mode power supply of 12v,/5amps.
1.2 PROBLEM STATEMENT
Switch Mode power supply was invented to solve problems observed in linear power supply such as low frequency and efficiency. Linear DC regulated power supplies (“linear supplies”) alter the output voltage to the required value through the power frequency (50/60 Hz alternating current) voltage transformer [8]. After being lowered (or raised) to the appropriate AC voltage value, the waveform is rectified, filtered, and stabilized by a voltage regulation circuit, and is then output as a regulated direct current (DC). These types of power supplies have a common characteristic; the voltage transformer works in the linear range [7]. The noise on the input is not amplified on the output. This makes for a quiet and stable output. But, there are drawbacks. The large static loss of the regulating element requires a large heat sink to cool the device and the physical size of a transformer that works in the power line frequencies (50/60 Hz) is large and heavy. Switching power supply was invented which does not operate at normal power line frequencies (50/60 Hz) but rather at considerably higher frequencies (several KHz to several MHz) [13]. In a switching power supply, the regulating device operates in the saturation or cut-off area as opposed to the linear power supply regulator which operates in the less efficient linear range. Switching power supply has Small size, lighter weight, and higher efficiency (can reach nearly 99%). It also have larger output ripple, RFI/EMI interference from pulsed power, higher output voltage if failure occurs [14].
1.3 AIM AND OBJECTIVES OF THE STUDY
This work is aimed at building a Switch Mode power supply of 12v,/5amps. The objectives are:
- To build the system prototype
- To overcome challenges seen in linear power supply
- To increase efficiency of power supply used in electronics.
1.4 SIGNIFICANCE OF THE STUDY
This work shall serve as a means of learning to how to build an efficient and high frequency power supply which can be used to power our appliances.
The study will also serve as an avenue of knowing the difference between linear power supply and Switch Mode power supply.
1.5 SCOPE OF THE STUDY
The scope of this work covers building a Switch Mode power supply incorporates a switching regulator to convert electrical power efficiently. It is mainly used for obtaining a controlled dc power supply as output. It is used to convert power (voltage) using switching devices that are turned on and off alternatively at high frequencies. It uses storage components like inductors or capacitors to supply power when the switching device is in its non-conduction state (off-state). SMPS possesses high efficiency and is widely used in various electronic equipment such as computers, battery chargers, and other sensitive equipment requiring a stable and efficient power supply.
SHARE PROJECT MATERIALS ON:
Switch Mode Power Supply
A Switch Mode Power Supply (SMPS), also known as a switched-mode power supply or simply a switching power supply, is an electronic power supply that converts electrical power efficiently from one form to another. Switch Mode Power Supply is widely used in various electronic devices and applications to provide a stable and regulated DC voltage or current output.
Here’s how a typical Switch Mode Power Supply works:
- Rectification: First, AC voltage from the mains (usually 110V or 220V AC) is rectified to convert it into a pulsating DC voltage. This is done using diodes.
- Filtering: The pulsating DC voltage is smoothed out using capacitors to reduce the ripple and obtain a relatively stable DC voltage.
- Switching Circuit: The core of the Switch Mode Power Supply is the switching circuit. It consists of a high-frequency electronic switch (often a transistor or a MOSFET) that rapidly switches on and off. This switching action turns the DC voltage into a high-frequency AC voltage.
- Transformer: The high-frequency AC voltage is then fed into a transformer, which typically steps down the voltage to a lower level. The transformer also provides electrical isolation between the input and output circuits.
- Rectification (Again): The output of the transformer is rectified again to obtain a high-frequency DC voltage.
- Filtering (Again): Another set of capacitors filters the high-frequency DC voltage to further reduce ripple and noise.
- Voltage Regulation: The final DC voltage may still need regulation to ensure it stays at the desired level despite variations in input voltage or load. This is usually done using feedback control circuits that adjust the duty cycle of the electronic switch in response to changes in output voltage.
- Output: The regulated DC voltage is then used to power electronic devices or circuits.
Switch Mode Power Supplies offer several advantages over traditional linear power supplies:
- Efficiency: Switch Mode Power Supply are highly efficient because they operate in a switching mode, meaning the power transistor is either fully on or fully off, minimizing power dissipation.
- Compact Size: Switch Mode Power Supply are generally smaller and lighter than linear power supplies with similar power ratings.
- Wide Input Voltage Range: They can work over a wide range of input voltages without significant loss of efficiency.
- Improved Regulation: Switch Mode Power Supply can provide better voltage regulation and stability compared to linear power supplies.
- Lower Heat Generation: Since they are more efficient, Switch Mode Power Supply generate less heat, making them suitable for devices with limited cooling options.
Switch Mode Power Supplies are commonly used in various electronic devices, including computers, mobile phone chargers, LED lighting, and many other applications where efficient power conversion is essential.