1. SMPS Lover

    SMPS Transformer noise and Low output voltage

    Hello, i have an issue with a 12v30A PSU: low output of 4v instead of 12v, SMPS transformer noise like low frequency issue. No short element in the secondary, RT/CT of tl 494 within specs, but i suspect the capacitor at VCC of TL494 : it is only 10mF and has only 7.5V. The DC output voltage...
  2. E

    Serge and spike protection to controller board

    i have developed a small board that has a controller and a 16x2 display. I am powering up the board using external smps power supply. I want to add serge protection, so that my system will be protected from any time of serge or spikes. One option is i can use fuse but i want to know what else...
  3. A

    SMPS POWER SUPPLY issue help needed

    Hello i am an engineering student working on a project of Switch mode power supply with outputs of 12V 1Amp .For this reason i have used power integration software to design smps supply circuit *(Schematic attached )with 12V 1 Amp required outputs. I have implemented this Circuit on PCB as...
  4. E

    Buck Converter from 48V to 5V

    I am using Arduino and Controlling FAN which works on 48v. so i am using 2 power supply smps in my design. One for Arduino that 5V smps and another for FAN that is 48V smps. I want to use single power supply in my design that is of 48Vdc. I was looking for a buck converter that will take 48V as...
  5. Younes Thabet

    How to calculate primary current in an smps transformer?

    Hello all, I have the following 12V center-tap transformer with below number of turns, I used (Np/Ns = Vp/Vs) to calculate output but i didn't get 12V although transformer specification says it's 12V. Can someone point out where I have mistaken? Also How can I calculate primary current given...
  6. J

    Tips for bipolar power supply

    Hello, I need to design a linear regulated supply to power an dac output stage based on op amp. It must be a negative + ground + positive one. The problem I encounter is that I don't know wich topology to select between the first and second arrangement. I suppose that the first one induce a...
  7. Younes Thabet

    What are design requirements of SMPS transformers need to be provided for manufacturer!?

    Hello all, I am designing a 12V, 18W Flyback SMPS and i can't figure exactly the characteristics of high-freq transformer (Both Core, Bobbin) to send for transformer manufacturer!! Can someone already went through these procedures guide me little bit!? Regards,
  8. Younes Thabet

    why is capacitive voltage divider connected to earth?

    What's the purpose of each part of circuit circled in the picture bellow!?
  9. emreanilterzioglu

    SMPS Vcc is not generating

    Hi guys, I am working on 12V 30A smps that has only 1V output. I haven't got board's schematic but I found one same like mine( Schematic Link). I measured high voltage capacitors (C2 and C3 on the schematic.) and bridge rectifier. They are working. Also checked power switching transistor on...
  10. H

    why voltage starts fluctuating when reduce ?

    i have a power supply of 24 volts and the circuit consist 103aiw dual op amp till 14 volts the power supply output stays stable but further more it's starts fluctuating but when load connected the voltage become stable please help me to find out the reason why without load the op amp don't work...
  11. anditechnovire

    Battery charging

    Please I have some couple of 3.6v 3Ah cylindrical li-ion battery, but since I bought them, charging it became a huge problem. I first connected a single one to a 2A infinix phone charger (made in china. According to the ratings, it capable of adjusting output current and voltage to load)thinking...
  12. anditechnovire

    Simple rcc flyback switching power supplies

    Please am studying about switching power supplies, starting from the simple ones. I've just concluded on joule thief and blocking oscillator, now am progressing to Self oscillating flyback converter(or RCC) and am finding a bit difficulty on how the transistor switches OFF. It seems the...
  13. anditechnovire

    Blocking Oscillator

    please am a beginner in electronics and am just getting to understand simple basic self oscillating circuit so i got stumbled in the so called one of the easiest self oscillating circuit, "the blocking oscillator". The information I get in many website are so confusing and contradicting...
  14. anditechnovire

    flyback and transformer concept

    I have been reading about the concept of a flyback transformers and converters, which has led to various misunderstandings concerning the basic operation of a transformer. Firstly, dc current don't induce voltage in the secondary windings of any transformer. But in a flyback converter, I read...
  15. Marcel DaJanchar

    SMPS IC selection for automotive use: 12V to 5V

    Hello! I am working on automated pressure controller which will be used in a car. The controller consists of following: - Power supply (10V-20V input, 5Vdc 1A max output) - MCU STM32 (valve controller for pressure regulation + reading 4 pressure sensors) - WiFi functionality (ESP8266) - 8...
  16. John Czerwinski

    DC Boost Converter (5v to 12v using LM2577) not powering load

    I'm sure I'm missing something very fundamental here, but I've built a boost circuit on a breadboard (see attached schematic) to convert 5v to 12v using an LM2577-adj. I want to power a 12v PC fan (rate at 12v at .06A) as the load. The LM2577 seems to work fine, as I'm measuring 12v. The fan...
  17. B

    How to improve efficiency of Full-Bridge SMPS?

    Hello, I am designing full-bridge SMPS with a linear voltage stabilizer in LTspice. When I was making measurements I discovered that the maximum efficiency of my power supply is around 30% at full load. Project assumptions: Input voltage: 230 AC Output voltage: 0 - 25 V DC Output current: 5 A...
  18. D

    Full Bridge DC-DC Converter - Closed Loop Compensation

    Hi everyone, I'm trying to make a 48V to 400V full bridge dc-dc converter and I'm using SG3525 as pwm IC. The question is; should I apply my 2-pole 2-zero compensation to the error amplifier on sg3525 or build a type-3 compensation on feedback part with tl431. (you can advise another method if...
  19. P

    Need to Design 48v to 12v DC 10A Max Circuit

    Hi, I need to design a DC DC Converter Circuit: 48v to 12v DC 10A Max Current with Isolation. Anyone, please share reference design/Schematics if any.