National Semiconductor LM 323 3-Amp, 5-Volt Positive Voltage Regulator Transon Hum EE136 PROJECT Analog Regulators Linear Regulators- Standard/NPN Positive Voltage - Fixed AbstractThis project involves the analysis and simulation of a 3-Amp, 5-Volt Positive Voltage Regulator designed and built by National Semiconductor. A basic overview of linear voltage regulators will be addressed. The claims of the manufacturer will be tested to determine the simulated parameters for input voltage range, load impedance, and maximum drive current. IntroductionToday, nearly all electronic circuits need some supply voltage. This regulated voltage must be clean, steady, and known. A linear voltage regulator creates this known voltage by means of transistor operating in their forward active regions and zener diode operating in their breakdown regions. The LM323 is a linear voltage regulator. A simulation of this circuit will be made to determine it’s effectiveness. Product Line:National Semiconductor Products(1776)Advanced PC (27) Analog - Amplifiers (307) Analog - Buffers (4) Analog - Comparators (40) Analog - Data Acquisition (115) Analog - Display Circuits(26) Analog - Flat Panel Display (36) Analog - Interface (173) Analog - References (33) Analog - Thermal Management (35) Analog - Other (37) Audio (62) Analog - Regulators (275) Automotive (60) Geode IA Products (9) Imaging (13) Microcontrollers (71) Microprocessor (3) Microprocessor Support (11) Military/Aerospace (347) Networks (26) Telecommunications (27) Wireless Communications (33) Wireless Base Station (6) Analog - Regulators(275)Lithium-Ion Battery Charge & Protection (5) Linear Regulators - Low Dropout Voltage (85) Negative Voltage - Adjustable (1) Negative Voltage - Fixed (1) Positive Voltage - Adjustable (22) Positive Voltage - Fixed (61) Linear Regulators - Standard/NPN (49) Negative Voltage - Adjustable (6) Negative Voltage - Fixed (11) Positive Voltage - Adjustable (12) Positive Voltage - Fixed (20) LM 323 3-Amp, 5-Volt Positive Voltage RegulatorRegulator Control & Supervisory Function (34) Switched Capacitor Converters (26) Switching Regulators (76) What is a VOLTAGE REGULATOR?A VOLTAGE REGULATOR provides an output voltage that is:1. STEADY 2. CLEAN3. KNOWN Under changing conditions such as: 1. Load Impedances and Load Currents 2. Unregulated or Fluctuating DC Input Voltage 3. TemperatureNote: LINEAR VOLTAGE REGULATORS can be either fixed or adjustable, depending on what the user demands.The LM 323 is a Fixed Linear Voltage Regulator. This means the regulated output of this circuit is designed to be fixed at 5V.What are VOLTAGE REGULATORS used for?Almost any electronic circuit needs a VOLTAGE REGULATOR. Examples:1. Computers 2. Microcircuits3. Amplifiers4. Almost all electronic circuits.What kind of VOLTAGE REGULATORS are there?There are basically 2 main types:1. Linear Regulators- Standard (internal feedback), Low-Dropout (external feedback), and Quasi Low-Dropout, etc.These types of circuits use the transistors operating in their linear active regions and zener diodes operating in their breakdown regions to create regulated voltages. 2. Switching Regulators- Buck, Buck-Boost, Boost, Flyback, Forward, etc. These types of regulators require switching circuits to either step up or step down the voltage.The LM 323 is a Standard Linear Voltage Regulator.How does a basic STANDARD LINEAR REGULATOR work?For a Linear Voltage Regulator to output a regulated voltage:1. An unregulated DC voltage source is connected to a voltage controlled current source.2. The current from this source is passed through some load impedance (RLOAD).3. A voltage (VOUT) is created across RLOAD.4. A feedback SENSOR that is connected to VOUTand the voltage controlled current source samples VOUT.5. The SENSOR compares VOUT with some reference voltage (VREF).6. If VOUT is equal to VREF, the SENSOR does nothing.7. If VOUT is different from VREF, the SENSOR inputs a voltage to the voltage controlled currentsource.8. The current source changes its output current to RLOAD until VOUT = VREF.Note: VOUT not VREF acts as a regulated output voltage.TESTING SIMULATIONNational claims the LM 323 Linear Voltage Regulator will:1.Take an unregulated DC input voltage between 7V and 20V and output a 5V (+/- 1%) regulated constant voltage. 2.It is also claimed to have a maximum output current of 3A. I will test these claims in simulation:1.Perform a DC sweep of the input voltage from 0V to 30V while monitoring the outputvoltage with nominal loads. 2.Change the load impedance to determine maximum output current.SIMULATION RESULTSInput Voltage Load Impedance Output Voltage Output Current7-14V 1M ohms 4.94V 4.94uA7-14V 1k ohms 4.94V 4.94mA7-14V 3 ohms 4.94V 1.7A7-14V 2.5 ohms 4.5V 1.84A7-14V 1 ohm 1.8V 1.8ANote that outside the input voltage range 7-14V the circuit does notact as a voltage regulator.CONCLUSIONS:The simulated linear voltage regulator works very well given the following conditions:1.Unregulated DC input voltage between 7V and 14V.2.With a load impedance greater than 2.5 ohms. Reasons that the simulation does not agree with the claimed specs of National:1. The intrinsic values of the transistors were notgiven in the LM 323 handout. This means the values of Beta and various impedances for the transistors are different than in the simulation. This will lead to different data measurements.According to National, the Advantages and Disadvantages of the LM 323 are:ADVANTAGES:1. Easy to use.2. Internal overcurrent and thermal protection.3. No circuit adjustments are needed.4. Low cost.DISADVANTAGES:1. Output voltage cannot be adjusted easily.2. It is available at only certain voltages.3. It is difficult to increase its current