Become a member of this channel and get benefits: / @technologycursosoficial COURSES TAUGHT BY PROF. VALDENILTON: Basic Electronics Course Level 1 and 2 Online (100% in VIDEO) https://go.hotmart.com/S90922297H?dp=1 LCD/LED Digital TV Repair Course (100% in PDF) https://technologycursos.wixsite.com/... Transformer Winding Course (100% in PDF) https://hotm.art/Curso-de-enrolamento... SHARE THIS VIDEO WITH THOSE YOU LOVE: • How the Control Circuit Works... VIDEOS TO COMPLEMENT THE UNDERSTANDING OF THIS CLASS: 1) Switching Power Supply Snubber Circuit • Never underestimate the snubber circuit of... 2) Never Replace a Fusistor with a Resistor • Watch This Class Before Replacing a... COURSES TAUGHT BY OTHER TEACHERS: Electronics Course Basic (with a focus on repair) https://hotm.art/Curso-de-eletronica-... Basic Electronics Course (with a general focus) https://hotm.art/Curso-de-eletronica-... Cell Phone Repair Course (version 5.0) https://hotm.art/Conserto-de-celular-top Notebook Motherboard Repair Course https://hotm.art/Conserto-de-placa-ma... Voltage Inverter Manufacturing and Repair Course https://hotm.art/Aprenda-a-fazer-inve... Photovoltaic Solar Energy Course https://hotm.art/Curso-energia-solar-... Complete Digital Marketing Course (from scratch) https://hotm.art/Curso-de-Marketing-D... SUBSCRIBE TO OUR CHANNEL BY CLICKING THE LINK BELOW: / @technologycursosoficial INTRODUCTION: Every switching power supply needs to keep the current flowing through the primary winding of the chopper transformer stable, regardless of the load consumption. In this series of classes consisting of three videos, you will learn how the current control circuit of the switching power supply works both in theory and in practice. ANALYSIS OF THE CURRENT CONTROL CIRCUIT (CS) OF THE SWITCHING POWER SUPPLY The control of the current flowing through the primary coil winding of the chopper transformer is performed by sampling the current that passes a resistor connected to the source terminal of the switching MOSFET of the switching power supply. When the primary current passes through the source resistor, a voltage drop is produced between its terminals. This voltage drop is then sent to the current control (CS) pin of the PWM Oscillator IC of the switching power supply. Internally to the Oscillator IC, an operational amplifier configured as a voltage comparator and biased with a reference voltage of 0.75 V reads the voltage of the CS pin and compares it with its reference voltage of 0.75 V. This comparison produces a correction voltage level for the PWM pulse control circuit. This voltage level will cause the control circuit to increase or decrease the width of the PWM pulses, thus determining the conduction of the switching MOSFET, which will keep the drain current constant, thus controlling the current in the primary winding of the chopper transformer. OVERCURRENT PROTECTION (OCP) OPERATION The current control circuit (CS) is also responsible for activating the overcurrent protection (OCP). This protection will be activated when the primary current rises and causes a voltage drop between the source resistor terminals equal to the threshold voltage of the current sensor pin (CS), which is 0.75 V. When the voltage drop reaches this value on the CS pin, the internal comparator generates a control voltage that disables the PWM pulse control circuit and the power supply is turned off, going to Standby. The resistor used as a Shunt is most often of the fusible type, with very low ohmic values, usually between 0.1 and 0.36 Ohms. Under no circumstances can this resistor be replaced by another that does not have the same electrical characteristics, nor the same type, which is a metal film. CONCLUSION: I hope that by the end of this series of three classes you have understood how the current control circuit of the switched-mode power supply works and can now perform maintenance on this device with greater safety and competence. Hello, I am Professor Valdenilton, Technical Coordinator of the Electronics courses taught by Technology Cursos. I love transforming people's lives through teaching. My goal is to teach people like you to repair the electronic equipment you love, helping in every way possible. INFORMATION: Our website: https://technologycursos.wix.com/tech... Business contact: [email protected] Whatsapp Center: (82) 9 8706-9200 (Only by messages or audio)