Hello experts, I need your help for the design of a source with half bridge topology. It is for a school internship, my teacher has been a misogynist with us so we don't have much support from him so I find myself begging for help.
Sorry to hear of the problem that you are facing. Are you able to work with other students? Is this a theoretical exercise, or do you have to produce a piece of hardware. In a practical system there is a lot more that has to be considered, particularly around the areas of electrical safety, circuit protection, EMI, and PCB layout. Do a web search on half bridges, source information on both the theoretical and practical aspects of this topology. Get the data sheet and applications information on the TL494, in particular on its use as a half bridge controller. TI have an app note https://www.ti.com/seclit/ug/slyu036/slyu036.pdf In a practical circuit you need a transformer to isolate the input from the output and to provide for a grounded load. You might also look at https://www.poweresim.com/index2.jsp?topology...=89&deduct=190&InitNow=T&pc=94209 for some more information. The application also includes a magnetics builder. Be weary of using simulators however, you still have to understand what you are doing (have a working circuit) and understand the simulators limitations before you use them to assist with your design. Get your information together, draw up a circuit with the key parameters on it, submit it to this forum and get some feedback. Cheers, Richard
Thank you very much for answering, no, we can't work with other students since only among women we can solve it... it's a whole issue but the school doesn't pay attention to us, anyway.
It is a practice so we have to build it, we have seen examples but what we do not understand is how to couple the TL494 with the IR2110, besides setting the frequency to 20 kHz. For the transformer, I know it is a high frequency transformer but we don't know its relationship so we have no idea about it.
This is a complex task if you have to build it, how long do you have and what facilities are available to you. You need to be positive about it, put everything else aside and just concentrate on the problem, if you have got where you are now, then you will have the aptitude to get through this. A word of caution, you are working with dangerous voltages, so take care. You are going to rely heavily on web based material, so I hope you have good access to the web. You need to break the problem down into discrete sections, start with block diagrams and fill the details out as you get more information and solutions. For example, input section with emi components, bridge, transformer, output, controller, isolated feedback loop, and bridge drivers. You will need a number of application notes to help you on your way, few of a number of examples below. https://www.youtube.com/watch?v=jbmI3phNx-0 https://article.sciencepublishinggroup.com/pdf/10.11648.j.ie.20210501.13.pdf https://octopart.com/blog/archives/2022/03/half-bridge-isolated-dc-dc-converter-design https://www.ti.com/lit/ug/sluu429b/sluu429b.pdf An earlier reference I gave you, https://www.poweresim.com/index2.jsp?topology...=89&deduct=190&InitNow=T&pc=94209 covers the transformer, the controller section is listed as generic, you could adapt the TL494 in that role, together with the MOSFET drivers. There is an application note here on the IR2110, https://web.mit.edu/6.131/www/document/float_drive.pdf The frequency setting for the TL494 is in the data sheet from TI. figure 7.1 shows the resistor and capacitor values. Transformer, ferrite core based, this is perhaps the most complex component, and is not easy to implement without access to a selection of magnet wire, insulating materials, tape, and transformer varnish. It should also be flash tested when complete. ttps://www.ti.com/lit/ml/slup126/slup126.pdf, https://tahmidmc.blogspot.com/2013/02/ferrite-transformer-turns-calculation_22.html Perhaps the most critical part is the physical layout on a PCB, high current, fast rise time paths, and creepage and clearance becomes an issue, slots in the PCB are often needed etc. Once built, you have to check the system for stability over the full range of input and output parameters. To repeat, this is a complex task, provided you have the theory sorted, can understand a data sheet, follow an application note in such a way that you can adapt it for your use, and do a PCB layout, you are well on the way. Personally I have never designed a half bridge inverter, but the approach to this is no different to any other circuit design, keeping your design requirements in mind, break the problem down into easily worked sub sections, or even to the component level (transformer, for example), a then work through each section using data sheets and application notes to fill in the details. All the best Richard
