If it's only going to 2.5v, then you have a problem somewhere.

The IR2110's input needs to get up to 9.5v or higher, and the maximum input bias to get there should be 40uA.

You say that you are using 1k pull-up resistors from the output of the comparators to 12v. (12v-2.5)/1k = 9.5mA current. That is many times the current that should be needed to get the inputs higher.

Is your 12v supply for Vdd on the IR2110 staying at 12v, or is it dropping? How about the 12v side of the 1k pull-up resistors?
If it is staying at 12v, then try replacing the IR2110 IC.

 

If it's only going to 2.5v, then you have a problem somewhere.

The IR2110's input needs to get up to 9.5v or higher, and the maximum input bias to get there should be 40uA.

You say that you are using 1k pull-up resistors from the output of the comparators to 12v. (12v-2.5)/1k = 9.5mA current. That is many times the current that should be needed to get the inputs higher.

Is your 12v supply for Vdd on the IR2110 staying at 12v, or is it dropping? How about the 12v side of the 1k pull-up resistors?
If it is staying at 12v, then try replacing the IR2110 IC.

When comparator output didn't connect to IR2110, I saw 0, 12 V PWM, but when connected outputs to the Ir2110, outputs of comparator was absurd. Problem is here.

Maybe current is too higher for IR2110. The buffer is a solution?What can I do?

 

Either the IR2110 is bad, the IR2110 Vdd input is less than 12v, or you have something else that is loading the input of the IR2110 to ground.

Try removing the IR2110 and see if the comparator output can then come up to 12v. If so, your IR2110 IC is bad.

 

Hi again,

I decided to make a new design for class d amplifier. For this turn, I'll generate triangle wave with lm311(for square wave) and lm318(for integration). But my space simulation didn't work. What can I do? My wave must have 200k 250kHz frequency.

R4 resistor for lm311's open-collector output, but I wasn't sure that is true

 

Where did you get that schematic? Just make it up, or did you copy it from somewhere and change it?

 

I made this schematic in orcad and I changed values more than one times. Butit didn't work.

 

Your schematic has some problems.

The LM318 really isn't fast enough for the 200-250kHz range.

Have a look at the attached schematic and simulation; I'm using two LM311's.

 

Your schematic has some problems.

The LM318 really isn't fast enough for the 200-250kHz range.

Have a look at the attached schematic and simulation; I'm using two LM311's.

Thank you, but I want to understand problems(except lm318 isn't fast.) Also lm311 isn't very fast and your triangle isn't ideal linear wave.

In my schema, first opamp is comparator and second one is normal op amp. should it be? Maybe I use two lm319(fast comparator) for this section??

Another way is using vco for triangle.ie lm566. It generates 1 MHZ square and triangle wave. what can you say?

 

You should use a comparator to sense the crossing of the audio and triangle waves. An opamp will have much lower rise/fall times.

If you would like to use an opamp for the triangle wave generator, go ahead.

I suggest you consult some reference designs, such as contained in this Applications Note:
http://www.ti.com/lit/an/slod006b/slod006b.pdf

 

I have this aplication note, but thanks.

I have two way. First, I'll use two lm319(fast comparators) or one opamp one comparator for generating triangle. One lm319 for comparating triangle and audio signal.

I read one upon a time that using two comparators for triangle wave isn't suitable ,especially second comparator, because the second comparator will generate triangle, not square. So in triangle wave generation section, I was thinking I use one opamp and one comparator.

Second way: I'll use lm566 for triangle wave and lm319 for comparating process.

Second way is safer and more linear, but output voltage of lm566 is between 1,9 V and 2.4 V(in datasheet). This level is high for triangle, because my mp3 player's output is maximum 0.4 v and I want to use mp3player in the end of the project.

What can I do? I want a hint or light.

 

Here, try it like the attached.

Signal "Tri" is ~240kHz, which is within your design criteria.

Rf was increased to decrease the amplitude of the triangle wave.

If you wish to decrease the amplitude of the triangle wave further, then increase Rf up as high as perhaps 200k, and increase C1 correspondingly to keep the frequency within range. You need to keep your input signal amplitude lower than the triangle wave.

 

Here, try it like the attached.

Signal "Tri" is ~240kHz, which is within your design criteria.

Rf was increased to decrease the amplitude of the triangle wave.

If you wish to decrease the amplitude of the triangle wave further, then increase Rf up as high as perhaps 200k, and increase C1 correspondingly to keep the frequency within range. You need to keep your input signal amplitude lower than the triangle wave.

Thank you, it works on pspice (with 2x lm319 and 1x lm318, and 3 x lm319. These two designs work on pspice)

But today I tried this design with 3 x lm319, but my output signal is very bad that it seemed sawtooth wave with 2 MHZ!!! And I changed resistors and used bigger cap, but freq and sawtooth didnt change. Also I tried 2 or 3 different lm319s.

Tomorrow I'll try it with lm318 lm319s. I hope it works.

 

You need to post your circuit.

LM319 comparators cannot source current from their outputs; only sink it - and they do not have internal compensation like opamps do.

 

I took the LM318 LM319 D amplifier driver schematic that I posted in reply #31, replaced the 318 opamp with a 319 comparator, connected the output emitters' terminal to Vee, added a 1k pull-up resistor to the output, and the triangle wave frequency went to ~248kHz and looked just fine in the simulation. Changing C1 from 1000pF to 1200pF decreased the frequency to ~200kHz.

 

I took the LM318 LM319 D amplifier driver schematic that I posted in reply #31, replaced the 318 opamp with a 319 comparator, connected the output emitters' terminal to Vee, added a 1k pull-up resistor to the output, and the triangle wave frequency went to ~248kHz and looked just fine in the simulation. Changing C1 from 1000pF to 1200pF decreased the frequency to ~200kHz.

i use your circuitand i connectedlm319 like lm318 ,added pull up resistor And tried from 1nf to 10nf cap to decrease freq, but freq is all The same.

Maybe problem is that supply voltage is 5v split supply And 1k pullup resistors
. in your circuit it is 10v

 

So, it WAS working in post 32 - and then you changed it, and it stopped working.

Post a photo of your circuit if you want help.

If you don't want help, then don't bother posting a photo of your circuit.

 

So, it WAS working in post 32 - and then you changed it, and it stopped working.

Post a photo of your circuit if you want help.

If you don't want help, then don't bother posting a photo of your circuit.

On simulation, yes it was working for two combination. But on physical world, it didn't work until now. I.e. following circuit that I made, it didn't work.

 

I guess I wasn't specific enough - I meant for you to post a photograph of your actual circuit, not an image of your schematic.

 

I can't take a photo, im not in school. But why does it require? I made my circuit on breadboard, does it help to you?

 

If you're on a breadboard, you probably have wires that are long, loopy, and have a lot of inductance. You need to make those wires as short as possible.

You need to make certain that you have 0.1uF bypass capacitors across the supply rails for each IC.