Hi, new here guys, not a total newb but need a bit of help IR2110 Inverter

added decoupling caps!

so I.ve made a start on the new inverter! have pics when done

Hi,

again about decoupling capacitors.
* general (safe) rule is: a fast capacitor at EVERY power supply pin of EVERY IC / load.
--> every power supply (pin) means: 12V, 5V, INPUT_DC .... maybe more (so if - for example - an IC has 3x 5V pins and 2x 3.3V pins then this means a total of 5 capacitors)
--> every IC/load (pin) means: U1, U2, U3, but also M1, M3 .. maybe more

Best is to read datasheets. U1 .. for example is rather uncritical .. I add them anyways.
And for sure it´s always the designer´s choice to remove them at uncritical pins .. or add some at more critical pins.

***
I see M1 and M3 rather critical. They carry high currents with fast edges. And thus every stray inductance will cause a voltage spike across their D-S.
These spikes - even if narrow in the sub microseconds range - may slowly kill your MOSFET (maybe over months) and usually result in a big bang!!!

Mind: Regarding stray inductance of traces: You CAN NOT compensate legthy traces with more thick or more wide traces.
This compensation only works for DC, but not for high frequency spikes.

Klaus

nearly finished the inverter! photos soon

almost finished!

Finished inverter!

There is space for sinks (slim sinks)!, can't see it being a problem! But I will try to make the cables as short as possible. But BTW I did over compensate with the long wires because you can always trim back wire than putting it back on! Is 50Hz considered "high" frequency? and also I put in a USB slot so that I can connect strait to the Arduino no probs, this part of the project is looking rather good to be fair; the wires that cross the entire board, blue and green are for the signal pins, an questions fire away!!!

Hi,

First: Your file size is huge. 100kBytes per picture should be sufficient wihtout losing thread related informations.
and: we miss the view to the back side.

Hope you don´t mind me being honest.
if you expect to be upset... please stop reading here.


Klaus

Like I said feel free to design me a PCB if you fancy! if you are up for it; but for now this will suffice for my needs at the moment. thanks for the constructive criticism! Also strip board or protoboard is for PROTYPING it's in the name!
And for that matter the entire thing is a prototype, the bulk of it is made from LEGO Technics, if you haven't noticed And I know there are guys out there that superior in their knowledge but give a man credit
In fact do you actually want to design me a PCB, it'd probably take you 5 minute with your skill set I'll find a site to etch it!
for your viewing pleasure the back side no pun intended

Hi,

I do PCB layouts for pay.
And I do the routing mainly by hand. So much more than 5 mins.

Yes, they are called protoboard. I know them since the 1970ies. That also was the time when they got their name.
And at that time they did a good job. ICs were slow, no WiFi and other HF around. No other devices around to get distrubed by the prototype.

But technology has advanced. (Protoboards not). IC´s are faster now .. no matter whether you run them only on 50Hz, the edges are fast and distribute a lot of HF noise.
Also they now react much faster on input signals ... also unwanted input signals, like WiFi, capacitively coupled signals, inductively coupled signals, ground bounce and so on.

In the 1970ies we had UKW in the 100MHz range with "critical trace lengths" of almost a meter.
And since the traces on the protoboard are much shorter ... they did not really work as transmitting antenna nor as receiving antenna.

Now that every IC has rise and fall times in the sub (or low) nanoseconds, the resulting frequency is in the 10s of GHz (mind: overtones caused by fast edges)
The critical trace length now shifts down to below some centimeters. Thus now the traces of the protoboard act as good antennas! .. even if you shorten them.

Again: this has nothing to do with your 50Hz switching frequency ... it´s only because ICs nowadays are much faster. And other HF sources are around.

***
In the 1970ies the signals were slow, this also means that for a signal on a trace with 10cm ... was considered to have the same signal (voltage) at both ends.
This is not true anymore. Your GND traces of 5cm in length (or even longer) may have a difference of several volts from one end to the other. Surely only for a short time, but due to the increase speed the ICs may react on this. It is likely to causes false trigger, ringing, oscillation, increased heating, malfunction, high voltage spikes, destruction.... in worst case explosion and fire.

***
PROTOTYPING.
Rapid prototyping is a common phrase today due to the availability of 3D printers.
Now if I 3D print a plastics prototype clamp for a bungee rope. Would you use this prototype for testing ... and jump?
I don´t think so. A prototype has several functions .. but also limitiations.

The 3D print bungee rope clamp may be use for photograph, for size considerations, for esthetic design considerations ... but it will not be fully functional.
The stability simply is too low for a real test.
The same is true for a protoboard and a switching power application. It is not suitable for functional testing. Even with no load.

***

I don´t say that your design does not work at all. It may work ... somehow. But maybe .. not at all.
But I can say it will not give any reliable results. You will gain not much information from this test setup.
You may connect a scope at it .... but if you compare the signal with what you "expect" or how the signal looks on a suitable design ... they will be so much different.
And even if it runs once .. it does not mean it runs a second time.

It´s like diving with a non certified Titan submarine. One can ignore the warnings of engineers, but one can not ignore physics.
****

All this has nothing to do with being disrespectful nor discouraging you from doing electronics.
I´m not here to annoy you. I´m here to tell you how electronics / physics works and what to care for.
--> I can only recommend to do it step by step.
--> And just want to warn you not to be surprised if it does not do what you expect it to do.

All well meant...
... and you are free to ignore my post(s)

Klaus

so how much for your services to make me a reliable board that is guaranteed to work? £20? ok I am seriously considering a PCB from you BUT I get paid two weeks tomorrow sooo... the FET's are IRF640 the LM7805 is the 5volt regulator the diodes are fast recovery 1000volt not sure which kind, I will have to check, I have the capacitors resistors and IR2110's, can you design it from this schematic below name a reasonable price and I would be happy to oblige! just need to wait 2 weeks

You may hire a hobbyist for £20 .

I do this professionally, for life, to raise my kids.. so nothing below £300.
And since you want a guarantee ... you have to provide a complete specification .. with a description about the test setup, how to prove proper operation.
And according this we can do a contract.

Klaus

KlausST said:

You may hire a hobbyist for £20 .

I do this professionally, for life, to raise my kids.. so nothing below £300.
And since you want a guarantee ... you have to provide a complete specification .. with a description about the test setup, how to prove proper operation.
And according this we can do a contract.

Klaus

Click to expand...

erm I was thinking 60 tops I think I will just stick with what I have for now maybe use your services in the future when I don't need "prototype" and move on to the real thing but that's comes later thanks for your time I'll stick to it working a couple of week perhaps couple of months use

good salesmanship though!

Maglatron, Klaus is trying to help you, please don't be offended by his comments.

Protoboard IS suitable for some things but inverters isn't one of them. It isn't a matter of whether it looks good or is mechanically strong, the additional inductance and high cross-talk between parallel copper strips is almost guaranteed to make it fail.

When we build inverters the positioning of components is critical, in particular the gate wiring to the MOSFETS, it should be a short as possible, preferably only a few mm and the grounding has to be very low impedance which means carefully placed fat tracks and again as short as possible. What isn't immediately obvious about inverters is the high currents that flow as very short (nS) spikes, even the gate current on the MOSFETs may reach several Amps, You may have noticed the IR2110 data sheet quotes up to 2.5A output current, that is so it can drive the MOSFET gate fast enough. One of the peculiarities of MOSFETS is that they draw virtually no gate current when a steady voltage is applied to them, however when you change the voltage on the gate a large gate current flows. From the driver circuits perspective it is rather like the gate to source pins are a large(ish) value capacitor and it has to be charged up and discharged each time the signal changes. If anything delays the charging and discharging, the MOSFET no longer works like a near perfect switch, during the rise and fall of the gate voltage (that capacitance charging and discharging), it behave like a partial conductor, somewhat similar to a resistor and therefore dissipates heat. The problem is further complicated because the MOSFETS are connected in 'totem pole', one above the other across the supply so if one hasn't turned off before the other turns on you get 'shoot through' and a partial short across the power rails. Long wiring, even just a cm or so will slow down the rising and falling times.

You can see why Klaus isn't happy with your design, the wiring is FAR too long and the signal paths are not low impedance. It might work but probably won't, regardless of functionality it will not work efficiently and you should expect energy wasted as heat in the MOSFETs.

Brian.

thanks