hi i want to created an H bridge inverter, i created pwm pulse with sg3525 and for driving the igbt's i want to use ir2101. in one schematic that i found in youtube it use the optocoupler and connect the pwm signals to input of 2 optocoupler and then connect the output's to HIN and LIN.am i have to use optocoupler with ir2101 for isolation?becuse in my understanding in IR2110 we dont need to optocoupler.
thank you

 

You don't need an optocoupler unless you need to isolate the signal ground from the bridge ground.

 

Tahmid's blog: Using the high-low side driver IR2110 - explanation and plenty of example circuits
Opto isolation is often used when the Output power is derived from mains AC direct.
Max.

 

You don't need an optocoupler unless you need to isolate the signal ground from the bridge ground.

dear crutschow thank you for reply, but what is your mean, am i have to isolate signal ground from the bridge ground?however i want to use one power supply to sg3525 and the ir2101 vcc , vdd and vb

 

Tahmid's blog: Using the high-low side driver IR2110 - explanation and plenty of example circuits
Opto isolation is often used when the Output power is derived from mains AC direct.
Max.

dear mr max thank you, can you explain more clear?thank you

 

If your power supply is directly off of the service supply, (no galvanic isolation) it will be referenced to earth ground and to the incomming supply, if you require the circuit producing the PWM, micro etc, to be isolated from the incoming service, safety reasons etc, then you would use opto isolators, otherwise there is usually no need for them.
Max.

 

If your power supply is directly off of the service supply, (no galvanic isolation) it will be referenced to earth ground and to the incomming supply, if you require the circuit producing the PWM, micro etc, to be isolated from the incoming service, safety reasons etc, then you would use opto isolators, otherwise there is usually no need for them.
Max.

thank you so much, so if i use the one adaptor 220/12 and the the lm7805 or greater for supply the control circuit like pwm circuit or driving circuit (by the way the adaptor produce non-isolated dc voltage) and the dc bus voltage 310 volt i dont need to opto isolators,am i right?

 

Optional, what is the source of the 310v?
Max,

 

Optional, what is the source of the 310v?
Max,

i made a 310 volt from diode bridge and regulate with 3 parallel 100uf dc cpacitor(dc bus) form grid 220volt ac voltage!

 

Then you must be aware that the controller can be at incoming supply potential if not opto isolation as the power common's would be connected.
Max.

 

Then you must be aware that the controller can be at incoming supply potential if not opto isolation as the power common's would be connected.
Max.

i dont understand what do you mean? dc bus controling!for dc bus controling i used a simple dimmer before diode bridge!

 

Then you must be aware that the controller can be at incoming supply potential if not opto isolation as the power common's would be connected.
Max.

dear mr max can you please explain more clear?thanks

 

But the way I read it you are obtaining the DC off of the 220v service direct?
If so you have no isolation between it and the low voltage control, this is OK as long as you are aware that the low voltage control is at the same potential reference.
What is the Dimmer for?
Max.

 

But the way I read it you are obtaining the DC off of the 220v service direct?
If so you have no isolation between it and the low voltage control, this is OK as long as you are aware that the low voltage control is at the same potential reference.
What is the Dimmer for?
Max.

hi max,the dimer for get the constant value for V/F equation,cuse you know if this equation dosent constant the motor goes to Saturation and operation get failed!

 

But the way I read it you are obtaining the DC off of the 220v service direct?
If so you have no isolation between it and the low voltage control, this is OK as long as you are aware that the low voltage control is at the same potential reference.
What is the Dimmer for?
Max.

finaly i decide to use IR2110 becuse i think it dosent need to optocoupler!!!i still dont understand why we use opto-isolator,cuse as you saide you want to isolated the supplys (control and power) i need a isolated power supply.ie a isolation transformer 220/12 and then i used the output of this transformer for control cicrcuit becuse if a use opto-isolator i have to supply the opto-isolator with this isolate voltage if i dont(i mean i use a typical non-isolated adaptor) the opto-isolator have the same ground with the power ground 310v.

 

Still not sure what you are doing, AFAIK all of the IR 2xxx series use the same common for the logic in and the power/output/driver section.
Which in that case there is no isolation, if you do need this, then an opto on the input signal to the IR is required.
Max.

 

If you need a fully logic side isolated H bridge driver IC these are what you are looking for.

http://www.ti.com/lit/an/slua778a/slua778a.pdf

They are just over $6 at digikey.

http://www.digikey.com/product-detail/en/texas-instruments/UCC21520DW/296-44611-5-ND/6140192

 

Still not sure what you are doing, AFAIK all of the IR 2xxx series use the same common for the logic in and the power/output/driver section.
Which in that case there is no isolation, if you do need this, then an opto on the input signal to the IR is required.
Max.

Dear max so why we use isolated voltage for HCPL-3120 ic ?for example for H-bridge inverter(for drive a single phase motor) we have to use 4 HCPL-3120 ic for IGBT's,i mean for each igbt we use one HCPL-3120, so we have to 4 isolated 12 or 15 voltage to 4 HCPL-3120,my question is are the ir2xxx ic need to isolated voltage like HCPL IC's,by the way the HCPL ic have the opto-isolator inside

 

If you need a fully logic side isolated H bridge driver IC these are what you are looking for.

http://www.ti.com/lit/an/slua778a/slua778a.pdf

They are just over $6 at digikey.

http://www.digikey.com/product-detail/en/texas-instruments/UCC21520DW/296-44611-5-ND/6140192

Dear tcmtech in fact i dont want isolation because Cost impact of isolated supply is significant.my quastion is that can i built a H-bridge drive with two ir2110 and 4 igbts with 1 non-isolated adaptor 220/12 for supply of control circuit(consist of pwm circuit and igbt's drive circuit)and some regulate capacitor for dc bus with diode-bridge for prouduce dc bus voltage?

 

Dear max so why we use isolated voltage for HCPL-3120 ic ?for example for H-bridge inverter(for drive a single phase motor) we have to use 4 HCPL-3120 ic for IGBT's,i mean for each igbt we use one HCPL-3120, so we have to 4 isolated 12 or 15 voltage to 4 HCPL-3120,my question is are the ir2xxx ic need to isolated voltage like HCPL IC's,by the way the HCPL ic have the opto-isolator inside

The HCPL offers isolation IF you REQUIRE it, the IR series do not REQUIRE isolation, it is only if your application Requires it that you use galvanic isolation.
The IR circuit will still function fine without any isolation on the control logic.
IOW if you use a IR charge pump driver and require isolation then an opto is used, otherwise, NO.
Max.