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Yes, that is true for many parts. A non-related area but, when I had a Ford Granada, the track rod ends were, say, $10UK each, but an identical track rod end for a Ford Escort (much smaller automobile) was £2.50UK.![]()
I use to run into that all the time at work name brand parts were unreasonable expensive but common identical parts were cheap, some companies were more expensive than others. Honeywell was the worse a $125 micro switch was only $1 from the Micro switch manufacturer, if you know what the replacement part is and where to buy it, it saves a lot of money. Now days companies call those, proprietary parts, I call it greedy deceptions.
See post #31. Texas instruments UCC21520, 2 of required, around $6.00US each from DigiKey, Mouser etc.What IGBT driver do I need? Where do I buy it? How much does it cost?
(Our posts crossed TCM)
I have never worked with these parks before, I have no clue what I am doing.
The other driver UCC21520 says it has a dead zone and it requires more parts with no part values on the drawing.?
Here you are Gary from the UC21520 data sheet:
You just need two of these circuits and connect the untapped primary of your induction heater between the two outputs.
We can suggest values and how to drive the completed bridge- that is not the difficult part.
The difficult part is getting the gate drives right and getting the high-power transistors (MOSFET or IGBT) happy driving the induction heater transformer.
The mains power supply will also beed to be sorted too.
spec
Quite simply the UCC21520 is the best performing driver on the market at the moment.
I have no problem with extra parts, I just don't know how to find the values of capacitors, resistors, diodes in that circuit.
What is the rectangle box to the left where it says, VCC, PMW, uC, Analog or Digital?
I don't know the abbreviation, VCC, VDD, VSS, SW?
I think HV DC link is probably the power supply?
Where does the load coil connect and does it have a capacitor bank like the mosfet circuit?
What is the symbol to the left of HV DC Link it looks like an Antenna symbol?
It is dead easy and just amounts to a resistor or voltage value- we can sort thatI understand what Dead Zone is that will be a much better circuit but never worked with this.
GreatI have no problem with extra parts.
We can sort that- don't worry it is no big dealI just don't know how to find the values of capacitors, resistors, diodes in that circuit.
It is just that- a box showing lots of options. It is a general way to shoe how the various signals could be controlled. In your application you would have just one in[put from an oscillator and that would be it. No sweat. It may look complex if you are not familiar with this part but there is nothing complicated really. As I say, we can show you all the connections you will need.What is the rectangle box to the left where it says, VCC, PMW, uC, Analog or Digital?
This is dead simple: VCC is the positive supply line for the logic on the chip. The ground symbol is the negative line of the same supply.I don't know the abbreviation, VCC, VDD, VSS, SW?
That is correct. It is just sloppy labeling again.I think HV DC link is probably the power supply?
One end of the coil connects to the point marked SW on the left half bridge and the other end of the coil connects to the same point point on the right half of the bridge. No capacitors are involved.Where does the load coil connect and does it have a capacitor bank like the mosfet circuit?
It is absolutely nothing- just sloppy drawing. You can rub it out if you want.What is the symbol to the left of HV DC Link it looks like an Antenna symbol?
The IR2113 is a damn good chip and, as you say, has been the go-to driver chip for a long time.I will have to look into those now. The old IR2113 has been my 'go to' H/L driver IC for years.
Yeah the isolation is good- it gives a great deal of flexibility in your design.That full isolation and ability to run as a dual fully isolated high side driver is what got my interest that and the less than $7 price tag.
The stuff I work with doesn't need the high speed though. I can't say I have ever had an application where I needed to run more than a few tens of KHz ever came up.
Gary, it seems to me that there are two good approaches for your induction heater:
(1) Full bridge (four transistors (MOSFET/IGBT)
(2) Half bridge (two MOSFET/IGBT) with +- supplies.
I think (2) has a lot of benefits so, for your consideration, I knocked out a quick block diagram to illustrating the approach using a single UCC21520 chip and two high power transistors:
**broken link removed**I have been a bit lavish with the 15V power supplies, and while two are not absolutely essential, they do give complete isolation between the logic and bridge. They also improve performance and make the operation of the circuit easier to understand. And PSUs are dirt cheap on the net anyway.
spec
Where do i get a 100KHz OSC .
What is divide by 2 ?
How many amps are the 15v PS ?
Great. I only put in +- 22V supplies because that was on one of the schematics that you previously posted. The bridge plus and minus supply voltages can be whatever you like, but they must be the same magnitude and must match the V/I characteristics of your coil for maximum heating and efficiency.I have 1200W MOT wired for 21V already but no CT. I have a 1400W MOT I can make into 22V with CT.
I was hoping to run the 1200V IGBTs on 120 vac with bridge rectifier and filter = 170 VDC on a 15 amp breaker. Low voltage is probably safer than to have a work coil running at 170V that might zap the heck out of someone.
Well spotted- please collect your prize from the mods.Looks like 1 of the diodes is backwards.
Easy peasy- I will post a schematic tomorrow. Its getting late here. The divide by two just ensures that you get an exact 1:1 mark-to-space ratio of the input waveform feeding the bridge driver. By the way the oscillator should be 200KHz to account for the divide by two stage.Where do i get a 100KHz OSC .
What is divide by 2 ?
Change PSUs to 12V at 1A (see ERRATA) Around 10 bucks each supply on ebay.How many amps are the 15v PS?
That will have to be analyzed and specified, but no big dealWhat are part values on diodes and capacitors?
-22V is the bridge negative supply rail.Where does -22v go ?
That will be calculated when we have details of the MOSFET/IGBT that you intend to use, but almost certainly a resistor with a diode in series with a resistor in parallel with the resistor.What connects to the other 2 terminals of Q1 and Q2?