Typical connection of IR2110

Hi all


pl. find the tipical connection ckt. giiven in IR2110 datasheet

I’m using this typical connection ckt. For driving a Lamp load( two 800w lamps in parallel—total resistance ==2.68 ohm) for my study experiment purpose.

Load supply voltage =300vdc;

I’m using IGBT instead of MOSFET

My switching frequency is 200HZ , 50 % duty cycle (is it too low???)
Hin & Lin pins are shorted just because to turn on & off both IGBTs at same time & for same period ; (is this right ???)

Problem I’ facing:::---

After exactly 35 ms the High side gate drive pulse (HO) is missing for 1 sec., while there is no problem fo LO, this reflects in Lamp blinking.
Currently My bootstrap capacitor is 1000uF.
I experimented with several values for bootstrap capacitor, Lesser the capacitor value HO missing is more frequent (timing is less then 35 ms) ;

Pl. can any one explain me what mistake I am doing ??

Also can I use this ckt to drive capacitive load ????

Thanks in advance

ir2110 application note

I think the problem is that you have the load connected between the two MOSFETs, but you do not have a full bridge. Thus, the bootstrap capacitor never has a chance to charge up, since the source of the the top MOSFET and pin Vs of the chip never reach ground potential. That means that no matter how large the cap, it will eventually discharge and the undervoltage lockuout in the chip will turn off the driver completely.
Then the cap charges up through the bottom MOSFET, when it is on. This MOSFET never stops working, because its driver is powered from a stable source, your bench supply. If this MOSFET stopped working too, then your cap would take much longer to charge up through the leakage current only.
When the voltage across the flyback cap reaches the threshold of the UVLO, the upper driver starts up again, and so on...

The solution I think is to simply use only one of the MOSFETs. If you use the lower one only, things will be even easier. But to test the theory, just use the top MOSFET only and connect the load between its source and ground. It should work fine, because now the flyback capacitor's bottom pin and pin Vs of the driver will be pulled to ground, through the lamps, whenever the MOSFET is off, which is 50% of the time.

By the way, I think your bootstrap cap is way too large.

ir2110 application

hi vvv

thanks for th e quick replay
I was busy in other works fro 2 days

as u have mentioned , Driving the load using Only high side or only low side MOSFET/IGBT switch. -- I had already done that expetiment & have no problems in Resistive load,

but when i connect the capacitive load 220 uF/400v + Lamp load I face the same problem. so I went for Half_Bridge configuration.

In Half-Bridge configuaration HO & LO pulses are same. So both ( high & low side) switches are on & off at same time. So
1>when both switches r ON bootstrap capacitor should discharge trough load-low side switch-ground
2>when Both switches are off bootstrap capacitor should charge to +VCC(15v) from a stable source

but this is not happening i believe

also
is my switching freq,(200 hz) too low ??
is this configuration is sutable for Capacitive load ???

well
thanks for ur mail

ir2110 application notes

I think that you have mixed some things in bootstrap operation.

1. You cannot charge the bootstrap capacitor while the upper switch is ON
( the voltage from the switch is going to Vs and while the switch is ON the
voltage on the cap is HVcc (500-600V)+voltace on the capacitor value at which it is charged to. So from your 15V which is your Vcc you can not charge the capacitor.)

2. The unique condition in which you can charge the capacitor is when the high switch is OFF and the low swith is ON.( in this case your voltage on VSS is conected to GND via lower FET and your VCC will charge the cap to 15V)

3. The condition which is happening to you is :
Your cap is charged to some voltage which can switch FET on.(lets suppose so) So when you open your switches at the same time you are not charging the bootstrap capacitor and it is discharging trough higher FET gate capacitance.In the moment in which you have reached UV lock out your high FET can not switch ON - but the lower can.In this moment you are charging your bootstrap and the cycle goes on.

4. Solution : A) You can use only lower switch ( which is the simplest)
B) put diverse signals to LIN and HIN (one low other high and change both atthe same time).In this case you can not use 100% pwm because with 100% pwm you are not charging the capacitors.

greetings
Dragan

ir2110 schematic

http://www.irf.com/technical-info/appnotes/an-978.pdf

Pages 14 and 19.

igbt ir2110

hi Dragan

thanks for or greetings;

right now I'm trying for the same, Iwill inform u about the results;

thanks for the help

yogikool

ir2110 full bridge

hI dragan:

I am just wondering, if I use the typical connection of the half bridge with the bus voltage up to 24V(0-12V-24V cos I connected the bottom rail to the ground)
when the lower switch is off all the time and upper switch is ON and OFF alternatively, in PWM fashion.
when the upper FET is ON, the source of the MOSFET will be 24V, then the boostrap cap will be discharged through the internal FETs. When the upper MOSFET is OFF, the source voltage on the upper MOSFET will reach to 12V, which will also enable the upper boostrap cap to be charged up. however, the voltage between the cap will be 3V, is this value enough to unlock the FETs?

if so, My question is:
In this case, is it necessary to make the upper boostrap cap smaller than the lower one which is designed for the lower side MOSFET. Since the source of the lower side MOSFET is connected to the ground all the time, there is no problem for the boostrap cap to be charged up.

application note ir2110

Lower driver is not using bootstrap circuit because it is not needed.If you need any help I will be glad if I can help you,but it will be much easier if you will provide us with the shematic of the circuit you are implementing and the modulation you are going to implement and of course the circuit you are going to connect to your output.For now I am attaching IR aplication note AN978 which is very good.

Dragan

ir2110 igbt

hi all

I am trying to experiment on the circuit as yogikool's circuit.

My problem is:
- The voltage of the SOURCE GATE of Higher MOSFET is always same as Gate voltage. it never get the Voltage Supply.
- I just get the pulse in L0 and can't get the pulse in H0

Pl can any one help me explain that problem

Thanks for reading

ir2110 bootstrap capacitor

Hi sunknu,

Can you please try what I suggested in my post?
Use just the upper transistor and the load connected from source to ground.

application ir2110

Hi vvv

thanks your reply. I already tried your post and succeeded with only lower MOSFET. But I just succeeded in this when I only use L0. Now I want to try two switches

Here is my circuit for my experiment



When I connect on the board, I am getting a very small signal which look like noise
Could you help me find out something wrong in my circuit

Best regards

ir2110

I cannot believe that using just the upper transistor with the load to ground did not work. Please check the bootstrap diode and cap.
Can you please describe what you are trying to achieve?
Are you trying to just PWM the voltage to a load, or are you trying to actually build a bridge? Because now there is no load, but there is a port labelled output.

ir2110 application

The anode of UF4007 must not be conected to VS pin (IR2110).

mosfet circuit ir2110

Hi GRAGAN:
the attached file is my schematic diagram.
there is one thing u should pay attention is , the topology I used is the buck-boost in each positive and negative cycle which is different from the traditional half-bridge operation with dead-time in it....

I am just thinking in this way, cos, my lower switch is OFF during the half period all the time, the upper cap will not connected to the ground which means it wont charge up properly if i use the typical connection from the application Kit
Now I am thinking of using two IR2110, using both of the lower drive port, with the ground connected to the mid of the battery, so that, the cap could be connected to the negative side of the battery. in this fashion, the cap could be charged up properly in order to make it higher than the threshold voltage for those FETs...

what u think?

how to use ir2110

VVV said:

I cannot believe that using just the upper transistor with the load to ground did not work. Please check the bootstrap diode and cap.
Can you please describe what you are trying to achieve?
Are you trying to just PWM the voltage to a load, or are you trying to actually build a bridge? Because now there is no load, but there is a port labelled output.

Click to expand...

hi vvv

I am trying to do experiment. I think first time the upper mosfets is on and the lower mosfets is off. Then the lower mosfets is on and the upper mosfets is off. So I can get the output. But I didn't get it until now.

There is load in my circuit. it is a inductor connected with a capacitor to ground.

Thanks for ur help

ir2110 example

hi all




ABOVE IS THE SCHEMATIC DIG. OF CKT. I AM USING FOR MY EXPERIMENT
R=5 OHM; C=6000 uF

WHEN I CONNECT ONLY R LOAD I DO NOT HAVE ANY PROBLEM
BUT
WHEN I CONNECT RC LOAD ---HO PULSES ARE PRESENT FOR FEW SEC. THEN HO REMAINS LO FOR FEW SEC. & THIS SEQUENCE CONTINUES.

DOSE THIS LOAD CAPACITOR AFFECTS THE WORKING OF BOOTSTRAP CAPACITOR???

YOGIKOOL

ir2110 example circuit

hi yogikool

Could you show me the output voltage.

Thanks

ir2110 pins describe

hi sunknu

please find hear the waveforms for

Load ==> R= 5 ohm, C=220uF/400v
Load supply voltage 30V dc



channel 3(pink )---Ho

channel 4(green)--Load

channel 2(blue)----Lo

u can see from wave forms that Load capacitor &bootstap capacitor do not discharge completely;

but what happens to that after few cycles???

diode for bootstrap operation on ir2110

yogikool said:

Hi all


pl. find the tipical connection ckt. giiven in IR2110 datasheet

I’m using this typical connection ckt. For driving a Lamp load( two 800w lamps in parallel—total resistance ==2.68 ohm) for my study experiment purpose.

Load supply voltage =300vdc;

I’m using IGBT instead of MOSFET

My switching frequency is 200HZ , 50 % duty cycle (is it too low???)
Hin & Lin pins are shorted just because to turn on & off both IGBTs at same time

I think the operating frequence is too low, you should use a larger value

bootstrap capacitor.

best regards





& for same period ; (is this right ???)

Problem I’ facing:::---

After exactly 35 ms the High side gate drive pulse (HO) is missing for 1 sec., while there is no problem fo LO, this reflects in Lamp blinking.
Currently My bootstrap capacitor is 1000uF.
I experimented with several values for bootstrap capacitor, Lesser the capacitor value HO missing is more frequent (timing is less then 35 ms) ;

Pl. can any one explain me what mistake I am doing ??

Also can I use this ckt to drive capacitive load ????

Thanks in advance

Click to expand...

ir2110 application information

Replay to Yogicol
From the oscilogram you provided I can see that you are doing exactly the thing I described in my previous discusion.You are switchilg theupper and the lower switch at the same time and my discusion still applays.

For Halisimon
I don't see the difference from my discusion.You are using push-pull un the transformer connected one side to 0 and with the high switch to +12 and with the lower switch to -12v. If your input signals are as in the shematics I do not see the reason to change the circuit.

Greetings
Dragan