driver for large igbt cm300ha - Page 1
Forum section: electronics / projects

author: ant17
author_rank: Regular Contributor
timestamp: February 22, 2016, 05:46:20 am
content: hi guys this is my first time on this site my name is anthony i am building a single pwrx cm300ha igbt flyback driver and i have a tl494 pwm wired for single output not push pull and works well on my 16vdc powersupply giving me roughly 16 volts peak to peak which is what i want i am using a tc4420 mosfet driver for high capacitive loads 6 amps peak in the datasheet it shows a sample circuit i have attached how i wired it but i am having trouble with it over heating and drawing to much current i am running them off the same power supplies i don't know if it is suppossed to have a separate supply and thats the problem its over heating before i even put a output load on it could someone please help

author: Phoenix
author_rank: Frequent Contributor
timestamp: February 22, 2016, 09:01:21 am
content: More detail..Quote from: ant17 on February 22, 2016, 05:46:20 amIs it the driver is over heating (or the IGBT)? Is it wired correctly? Is it outputting the correct signal?What switching frequency and supply rail voltage, have you calculated the loss based on the crossover energy (listed in the data sheet graphs)? Which package?Do you have a circuit diagram for what you've actually done (not just copied from the datasheet)?

author: CM800
author_rank: Frequent Contributor
timestamp: February 22, 2016, 09:53:04 am
content: Quote from: ant17 on February 22, 2016, 05:46:20 amHave you installed a gate resistor? Around 1 Ohm would be suitable likely.

author: ant17
author_rank: Regular Contributor
timestamp: February 22, 2016, 10:18:28 pm
content: no i have not yet drawn a schematic on what i have done when the chip over heats it heat up really fast enough to burn my finger the rail voltage is 16vdc and found with no output load or input signal it does not overheat i was putting 16volt peak to peak directly in pin 2 the input its a pdip8 package i wonder if i am putting to much voltage into the input

author: CM800
author_rank: Frequent Contributor
timestamp: February 22, 2016, 11:03:32 pm
content: Yeh, check this out:(from my calculator program I made up)

author: ant17
author_rank: Regular Contributor
timestamp: February 23, 2016, 12:14:49 am
content: thanks guys by p-p i mean 16 volts peak to peak the switching is about 25khz. The tl494 circuit and tc4420 the tl494 is happy but the tc4420 does not seem to like to run off the same power supply. i have been playing around with it and i have found with say 5 to 10 volts peak to peak likes it alot better esspecialy with diffrent powersupplies.

author: ant17
author_rank: Regular Contributor
timestamp: February 23, 2016, 03:06:53 am
content: i just measured my signal from the tl494 and when you from all the way clockwise to all the way counterclockwise with the duty cycle adjustment pot it shifts the centre point of 16v to 16volts above ground and 16v below ground it can even be adjusted to the centre so 8v+ and 8v- and when just checked it the whole 16v was below ground so i think that might be the problem because that would mean its -16 on and as you said the clamps would clamped it and caused it overheat do you agree

author: ant17
author_rank: Regular Contributor
timestamp: February 23, 2016, 10:52:34 pm
content: i have now drawn a simple schematic hope everyone can follow it you may have to download it and zoom in

author: Phoenix
author_rank: Frequent Contributor
timestamp: February 24, 2016, 01:00:48 pm
content: Quote from: AcHmed99 on February 24, 2016, 12:03:10 pmThe emitters do need a pull down resistor - this will create an emitter follower arrangement.QuoteI don't think is necessary to parallel the two outputs, it's just driving a logic like input.And I agree; experimenting with a 300A IGBT without knowing what you're doing - you're probably going to blow something up.

author: ant17
author_rank: Regular Contributor
timestamp: February 24, 2016, 10:16:56 pm
content: ok thanks fellas i will try a 1k pull down resistor and consider using one push pull output thanks agian i will let you know how i progress