# Help me building a IRFZ44 H-bridge

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#### Faizan Jawaid

##### Full Member level 3
I need to design a mosfet based h-bridge which can handles upto 5A load. Some advice me to use IR2104 mosfet driver for the purpose with IRFZ44 mosfets. I tried to made the circuit given in IR2104 datasheet as a typical circuit. But Both the IC and the Mosfets are heating up hard. Vds i gave is 12 volts. And IC supply voltage i gave was also 12V. Please advice me any schematic based on IR2104 or equivalent.

Thanks

#### sec

ir2104

What is the frequency? Is it for audio application or power supply ? Are you using resistor between the output and the gate of the mosfet ?

Ugurr and jpies

Points: 2

### Ugurr

Points: 2

#### darla1

##### Full Member level 3
ir2104 application notes

can you post schematic

darla

#### Faizan Jawaid

##### Full Member level 3
ir2104 schematic

Hello People...This is the schematic i worked on...But i dont know what i am doing wrong. The schematic will be used to make a Full Bridge driving 5A DC motor. The IC is heated to about 40C and mosfet are heated near to burning. I in beginning check the circuit using a small DC motor as the load (I<500mA). The Frequency was a far issue. When there was no transition of the IN PIN. i.e pulled high the problem remains the same. Please advice.

Regards.

#### darla1

##### Full Member level 3
ir2104 application

hi

please chnage the diode of 1n4001 to MUR-120, asper my knwoldge it rquires fast switching diode....i am using IR2111 same as ur device with MUR120 diode for full bridge converter.

and why you are using the capacitor commom for both MOSFETS.

first check the lower and higher pulses ...at your switcing frequency.....

then connect it to mosfets and check output....without connecting any load or some small value of resistor...

if operaion is fine the conncet ur load

darla

Ugurr and rajivaik

Points: 2

### Ugurr

Points: 2

#### Faizan Jawaid

##### Full Member level 3
ir2104 h bridge

Darla, Like i told you ive used the configuration as the datasheet told me. The 0.1uF capacitor is placed between the Vb and Vs of the IR2104. You mean the schematic is OK?

#### darla1

##### Full Member level 3
power h bridge

schematic is OK for one leg but u did not shown full schematics

please show full schematic with actual setup....

darla

#### Faizan Jawaid

##### Full Member level 3
power h bridge schematics

Ill be thankful if you post your schematic of the converter. Ill compare it. Itll be easy for me to rectify mine.

#### darla1

##### Full Member level 3
ir2104 circuit

hey i can not post my schemtics since it is confidential if u post i ll make corrections for ur schematic

#### Faizan Jawaid

##### Full Member level 3
build h-bridge 100a

Hi Darla, I m posting the schematic of my design. This is the complete schematic of the power side except the controller part which is optoisolated. Please advice me any changes if required.

Thanks

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#### Siniša

##### Full Member level 6
irfz44 h-bridge

Visit IR web page, they have some nice application notes there.

You should have gate resistors, diodes for mosfet protection, some RC in parallel to motor,...

You did not specify what is switching frequency. Also the details of how you power everything are not shown. Read through application notes, measure your circuit and try to understand what is hapening. Frequency should not be too high or too low. Try with 2-3 kHz first. Put some filter on output as well. It is most likely you got some oscillations happening because of too fast switching of your mosfets, but could be a number of reasons. Make sure that +12V is clean and not affected by motor current. All the specs are stated for +15V, you should use the same if possible. It just give you more headroom as minimum is 10 and maximum is 20 volts.

There are plenty of examples of driving motors at various semiconductor manufacturer sites and they give schematics of reference designs that include complete working design that you could modify to suit your application.

vijaydeepbhatt

### vijaydeepbhatt

Points: 2

#### Faizan Jawaid

##### Full Member level 3
ir2104s appnote

switching frequency would be 1Khz...

A low value gate resistor...10ohm?

for protection diode...MUR860?

odie

### odie

Points: 2

#### TekUT

##### Full Member level 6
irfz44 h bridge

Gate resistor of 10 Ohm should be a good starting point, look at the load for every hi-frequency ringing, this can be responsible for MOSFET power dissipation, put the resistor and make same measure to see if the ringing disappear. Of course enlarge the gate resistor value prevent hi-freq oscillation and EMI but also slow down the commutation and increase the commutation power loss of the MOSFET, the gate resistor value is a trade off from power loss (switching time) and EMI requirement.

Bye
Pow

#### Siniša

##### Full Member level 6
using ir2104

For 1kHz switching frequency, go for 100 even 220 ohms for gate resistor. There will be no significant heating due to extended swtching time.

Diode is a bit overkill, but will do.

#### Faizan Jawaid

##### Full Member level 3
h-bridge gate oscillations

This schematic is for testing. Ive connected an inductive load to test. The problem is that when i connect no load the output shows 10V and when load is connect the voltage is dropped to 0.4V whether u give high or low to the IN.

regards

### Electronics_chaitanya

Points: 2

#### FvM

##### Super Moderator
Staff member
ir2104 circuit

That can be expected, cause these type of bootstrap driver can't achieve 100% duty cycle, it must have a residual low period to charge the boostrap capacitor. There are special types with a recharge circuit for static switches.

#### Faizan Jawaid

##### Full Member level 3
ir2111 h bridge

So FVM, u mean circuit will work if i increase the frequency as well as i reduce Duty less than 100%?

#### FvM

##### Super Moderator
Staff member
h bridge using ir2104

Yes, according to the datasheet.

Points: 2

### jit_singh_tara

Points: 2

#### darla1

##### Full Member level 3
full bridge using ir2111

hey javed

one more suggestion use o.iu at Vcc to Com and test total circuit at 10K

if not let me know ....i am operating this now at 10KHz for full bridge inverter

darla

### Electronics_chaitanya

Points: 2

#### Faizan Jawaid

##### Full Member level 3
h bridge converter

darla1 said:
hey javed

one more suggestion use o.iu at Vcc to Com and test total circuit at 10K

if not let me know ....i am operating this now at 10KHz for full bridge inverter

darla

Why would be .1u cap is be necessary. FVM suggestion is right. The cap needs time to charge/discharge. At higher frequencies the results will be near to perfection. And Yes the low time is also important in duty cycle which`ll make the cap to charge.

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