ECE121 Electronics (1) Lecture 1 - Regulated Power Supply PDF

ECE121: Electronics (1) Lecture 1: Regulated Power Supply Dr. Haitham El-Hussieny Electronics and Communications Engineering Faculty of Engineering (Shoubra)...

ECE121: Electronics (1) Lecture 1: Regulated Power Supply Dr. Haitham El-Hussieny Electronics and Communications Engineering Faculty of Engineering (Shoubra) Benha University Spring 2017 Dr. Haitham El-Hussieny ECE121: Electronics (1) 1 / 28 Lecture Outline: 1 Introduction. 2 Concept of Voltage Regulation. 3 A Zener-Regulated DC Power Supply. 4 Basic Linear Voltage Regulator. 5 Integrated Circuit Voltage Regulators. Dr. Haitham El-Hussieny ECE121: Electronics (1) 2 / 28  Introduction. Table of Contents 1 Introduction. 2 Concept of Voltage Regulation. 3 A Zener-Regulated DC Power Supply. 4 Basic Linear Voltage Regulator. 5 Integrated Circuit Voltage Regulators. Dr. Haitham El-Hussieny ECE121: Electronics (1) 3 / 28  Introduction. Introduction: DC Power supply: Around 95% of the electronic equipments are powered from low voltage DC supplies. Dr. Haitham El-Hussieny ECE121: Electronics (1) 4 / 28  Introduction. Introduction: DC Power supply: Around 95% of the electronic equipments are powered from low voltage DC supplies. The source will be either a battery or a power supply converting AC mains into one or more low voltage DC supplies. Dr. Haitham El-Hussieny ECE121: Electronics (1) 4 / 28  Introduction. Introduction: DC Power supply: Around 95% of the electronic equipments are powered from low voltage DC supplies. The source will be either a battery or a power supply converting AC mains into one or more low voltage DC supplies. Electronic components require a DC supply that is well regulated, has low noise characteristics and provides a fast response to load changes. Dr. Haitham El-Hussieny ECE121: Electronics (1) 4 / 28  Introduction. Introduction: Components of DC Power Supplies: 1 The AC voltage, typically 220 V RMS, is connected to a transformer, which steps that ac voltage down to the level for the desired dc output. Dr. Haitham El-Hussieny ECE121: Electronics (1) 5 / 28  Introduction. Introduction: Components of DC Power Supplies: 1 The AC voltage, typically 220 V RMS, is connected to a transformer, which steps that ac voltage down to the level for the desired dc output. 2 A diode rectifier then provides a full-wave rectified voltage, which is initially filtered by a basic capacitor filter to produce a dc voltage. Dr. Haitham El-Hussieny ECE121: Electronics (1) 5 / 28  Introduction. Introduction: Components of DC Power Supplies: 1 The AC voltage, typically 220 V RMS, is connected to a transformer, which steps that ac voltage down to the level for the desired dc output. 2 A diode rectifier then provides a full-wave rectified voltage, which is initially filtered by a basic capacitor filter to produce a dc voltage. 3 A regulator circuit can use this dc input to provide a dc voltage that remains constant if input or load changes. Dr. Haitham El-Hussieny ECE121: Electronics (1) 5 / 28  Introduction. Introduction: Ideal Vs. Real DC Regulated Power Supply: Ideal Power Supply: It provides a constant dc voltage despite changes to the input voltage or load conditions. Dr. Haitham El-Hussieny ECE121: Electronics (1) 6 / 28  Introduction. Introduction: Ideal Vs. Real DC Regulated Power Supply: Real Power Supply: The output voltage of a real power supply changes under load or line (input) change. Dr. Haitham El-Hussieny ECE121: Electronics (1) 7 / 28  Concept of Voltage Regulation. Table of Contents 1 Introduction. 2 Concept of Voltage Regulation. 3 A Zener-Regulated DC Power Supply. 4 Basic Linear Voltage Regulator. 5 Integrated Circuit Voltage Regulators. Dr. Haitham El-Hussieny ECE121: Electronics (1) 8 / 28  Concept of Voltage Regulation. Concept of Voltage Regulation: Line Regulation: Line Regulation: It is the percentage change in the output voltage for a given change in the input voltage. It can be expressed in units of (%/V ). Dr. Haitham El-Hussieny ECE121: Electronics (1) 9 / 28  Concept of Voltage Regulation. Concept of Voltage Regulation: Line Regulation: Line Regulation: (Example) When the ac input voltage of a certain power supply changes, the input to the voltage regulator decreases by 5 V as a result, and the output of the regulator decreases by 0.25 V. The nominal output is 15 V. Determine the line regulation in %/V. Solution: The line regulation as a percentage change per volt is: (∆ Vout /Vout )100% (0.25 V /15 V )100% Line regulation = = = 0.333%/V ∆ Vin 5V Dr. Haitham El-Hussieny ECE121: Electronics (1) 10 / 28  Concept of Voltage Regulation. Concept of Voltage Regulation: Load Regulation: Load Regulation: It is the percentage change in output voltage for a given change in load current. One way to express load regulation is as a percentage change in output voltage from no-load (NL) to full-load (FL). Dr. Haitham El-Hussieny ECE121: Electronics (1) 11 / 28  Concept of Voltage Regulation. Concept of Voltage Regulation: Load Regulation: Load Regulation: (Example) A certain voltage regulator has a 12 V output when there is no load When there is a full-load output voltage is 11.9 V. Express the voltage regulation as a percentage change from no-load to full-load. Solution: The load regulation as a percentage change from no-load to full-load is: (VNL − VFL ) (12 V − 11.9 V ) Load regulation = 100% = 100% = 0.840% VFL 11.9 V Dr. Haitham El-Hussieny ECE121: Electronics (1) 12 / 28  A Zener-Regulated DC Power Supply. Table of Contents 1 Introduction. 2 Concept of Voltage Regulation. 3 A Zener-Regulated DC Power Supply. 4 Basic Linear Voltage Regulator. 5 Integrated Circuit Voltage Regulators. Dr. Haitham El-Hussieny ECE121: Electronics (1) 13 / 28  A Zener-Regulated DC Power Supply. A Zener-Regulated DC Power Supply: The zener diode can be used as a type of voltage regulator for providing stable reference voltages. Dr. Haitham El-Hussieny ECE121: Electronics (1) 14 / 28  A Zener-Regulated DC Power Supply. A Zener-Regulated DC Power Supply: The zener diode can be used as a type of voltage regulator for providing stable reference voltages. As the input voltage varies (within limits), the zener diode maintains a nearly constant output voltage across its terminals. Dr. Haitham El-Hussieny ECE121: Electronics (1) 14 / 28  A Zener-Regulated DC Power Supply. A Zener-Regulated DC Power Supply: The zener diode can be used as a type of voltage regulator for providing stable reference voltages. As the input voltage varies (within limits), the zener diode maintains a nearly constant output voltage across its terminals. However, as VIN changes, IZ will change proportionally so that the limitations on the input voltage variation are set by the minimum and maximum current values (IZK and IZM ) with which the zener can operate. Dr. Haitham El-Hussieny ECE121: Electronics (1) 14 / 28  A Zener-Regulated DC Power Supply. A Zener-Regulated DC Power Supply: At No-load Dr. Haitham El-Hussieny ECE121: Electronics (1) 15 / 28  A Zener-Regulated DC Power Supply. A Zener-Regulated DC Power Supply: At Full-load Dr. Haitham El-Hussieny ECE121: Electronics (1) 16 / 28  Basic Linear Voltage Regulator. Table of Contents 1 Introduction. 2 Concept of Voltage Regulation. 3 A Zener-Regulated DC Power Supply. 4 Basic Linear Voltage Regulator. 5 Integrated Circuit Voltage Regulators. Dr. Haitham El-Hussieny ECE121: Electronics (1) 17 / 28  Basic Linear Voltage Regulator. Basic Linear Voltage Regulator: Regulated Power Supplies Linear Power Supplies Switched Power Supplies Series Linear Regulators Shunt Linear Regulators Dr. Haitham El-Hussieny ECE121: Electronics (1) 18 / 28  Basic Linear Voltage Regulator. Basic Linear Voltage Regulator: Series Linear VR: The control element is a pass transistor in series with the load between the input and output. Simple series voltage regulator Dr. Haitham El-Hussieny ECE121: Electronics (1) 19 / 28  Basic Linear Voltage Regulator. Basic Linear Voltage Regulator: Series Linear VR: The control element is a pass transistor in series with the load between the input and output. The output sample circuit senses a change in the output voltage. Simple series voltage regulator Dr. Haitham El-Hussieny ECE121: Electronics (1) 19 / 28  Basic Linear Voltage Regulator. Basic Linear Voltage Regulator: Series Linear VR: The control element is a pass transistor in series with the load between the input and output. The output sample circuit senses a change in the output voltage. The error detector compares the sample voltage with a reference voltage and causes the control element to compensate in order to maintain a constant output Simple series voltage regulator voltage. Dr. Haitham El-Hussieny ECE121: Electronics (1) 19 / 28  Basic Linear Voltage Regulator. Basic Linear Voltage Regulator: Series Linear VR: The resistive voltage divider senses any change in the output voltage. The op-amp circuit amplify the difference voltage (error voltage) between the reference and the sensed values. This amplified difference voltage is applied to the transistor Q1 to make the load voltage equals to the reference. Basic op-amp series regulator Dr. Haitham El-Hussieny ECE121: Electronics (1) 20 / 28  Integrated Circuit Voltage Regulators. Table of Contents 1 Introduction. 2 Concept of Voltage Regulation. 3 A Zener-Regulated DC Power Supply. 4 Basic Linear Voltage Regulator. 5 Integrated Circuit Voltage Regulators. Dr. Haitham El-Hussieny ECE121: Electronics (1) 21 / 28  Integrated Circuit Voltage Regulators. Integrated Circuit Voltage Regulators: Integrated circuit voltage regulators are available as series regulators. The IC regulator contains the reference voltage, the error detector and the control unit in one package. IC Regulators Fixed Voltage Variable Voltage Positive Output Negative Output (78xx) (79xx) Positive Output Negative Output (LM317) (LM337) Dr. Haitham El-Hussieny ECE121: Electronics (1) 22 / 28  Integrated Circuit Voltage Regulators. Integrated Circuit Voltage Regulators: Fixed Positive Linear Regulator (78xx) The last two digits in the part number designate the output voltage. For example, the 7805 is a 5 V regulator. The 78XX series Dr. Haitham El-Hussieny ECE121: Electronics (1) 23 / 28  Integrated Circuit Voltage Regulators. Integrated Circuit Voltage Regulators: Fixed Negative Linear Regulator (79xx) The last two digits in the part number designate the output voltage. For example, the 7905 is a -5 V regulator. The 79XX series Dr. Haitham El-Hussieny ECE121: Electronics (1) 24 / 28  Integrated Circuit Voltage Regulators. Integrated Circuit Voltage Regulators: Variable Positive Linear Regulator (LM317) The external fixed resistor R1 and the external variable resistor R2 provide the output voltage adjustment. The output can be varied from 1.2 V to 37 V depending on the resistor values. The LM317 can provide over 1.5 A of output current to a load. We can neglect IADG which is small 50 µA. Dr. Haitham El-Hussieny ECE121: Electronics (1) 25 / 28  Integrated Circuit Voltage Regulators. Integrated Circuit Voltage Regulators: Variable Negative Linear Regulator (LM337) The external fixed resistor R1 and the external variable resistor R2 provide the output voltage adjustment. The output can be varied from -1.2 V to -37 V depending on the resistor values. The LM337 can provide over 1.5 A of output current to a load. We can neglect IADG which is small 50 µA. Dr. Haitham El-Hussieny ECE121: Electronics (1) 26 / 28  Integrated Circuit Voltage Regulators. Integrated Circuit Voltage Regulators: Power Supply Project: Example of a typical 12 V power supply: Select one of the IC regulator and simulate it individually using Proteus. Send it by Sunday 19 Feb. 2017. Each team (one to four members) should deliver a variable (+ve or -ve) power supply by Sunday 26 Feb. 2017. Dr. Haitham El-Hussieny ECE121: Electronics (1) 27 / 28  Integrated Circuit Voltage Regulators. End of Lecture Best Wishes [email protected] Dr. Haitham El-Hussieny ECE121: Electronics (1) 28 / 28