IRS2092 with IRFB4227 problem!

[nigelwright7557]

You can get away without gate buffers if you use 4019 mosfets.

I used irfb4227's and they need gate buffers and 4r7 gate resistors.

 

[wahyuos]

hi wahyuos you havent used gate drive buffers e.g bd139 and bd140 or smd ztx series ? ir2092 needs buffer stage unless you are using special output fets😉

BD139 and BD140 replaced tc4402, this from a friend who'll make pcb

 

[soky7]

Hi

I have some question, is always necessary gate buffers for one pair IRFB4227 ?
If yes, how its work something like this ?
https://www.aliexpress.com/item/YJ-IRS2092-IRFB4227-500W-500W-4ohm-Class-D-Stereo-Amplifier-board/32808598635.html?spm=2114.01010208.3.156.CaqQ0q&ws_ab_test=searchweb0_0,searchweb201602_4_10152_10065_10151_10068_10136_10137_10060_10155_10062_437_10154_10056_10055_10054_10059_303_100031_10099_10103_10102_10096_10052_10053_10142_10107_10050_10051_5030018_10171_10084_10083_10119_10080_10082_10081_10110_519_10111_10112_10113_10114_10182_10078_10079_10073_10123_10120_10189_142,searchweb201603_16,ppcSwitch_5&btsid=79864f10-edb0-4401-a300-dcd70b76184a&algo_expid=bd376fc0-5727-483c-b25f-b833683e2361-21&algo_pvid=bd376fc0-5727-483c-b25f-b833683e2361

And my last question, is possible to upgrade IRAUDAMP9 to +-92V rail ? it will be worked ?
thanks

 

[stewin]

i saw a pioneer 2000wts using ktc1027 & kta1023 a pair in parallel to drive 3pairs of irfb4227 using irs2092. the power supply voltage capacitors were rated at 80vlts. the amp was rated at 1ohm stable

 

[IVX]

For a compact buffer, I would like to recommend this one BJT pair in SOT-23 https://www.diodes.com/assets/Datasheets/ZXTC2045E6.pdf

 

[wg_ski]

How about the (now unobtainium) A2127/C6043? Originally bought for other purposes, but look suitable.... or are the ZTX690/749 still the better choice?

 

[IVX]

How about the (now unobtainium) A2127/C6043?

DC gain around 80 @ 2A, it's good enough as well. Actually, even bc807/817 may help 2093 to drive relatively heavy mosfet's, but for sure it's not an optimal choice, and, for instance PBSS5320T/ PBSS4320T would be much better.

 

[soky7]

Hi

I have design with IRS2092 and one pair IRFB4227
configuraton : +-80 rail, VCC=15.5V measured on board, driver for IRFB4227
is ZXTN25100BFH and ZXTP25100BFH, Rb for driver is 0R and Rg for mosfet is also 0R, switching frequency is 380kHz, DT is 105ns, amplifier has power around 550W RMS with 1khz sine wave for 4ohm, but driver for mosfet is very hot around 70-90°C, if I change Rg to 4R7, duration of rise edge is longer and mosfet are very hot, next feedback consist of 1k and 100K resistors and
150pF cap, 1k resistor is also very hot(90°C) footprint is 1206, Does anyone know why? thanks.

 

[Eva]

Gate NPN/PNP buffers need some base resistance, like 10r, to control saturation and reverse behavior.

 

[soky7]

if I change Rb to 4R7, duration of rise edge is also longer, in originally schematics iraudamp9 is Rb 0R

 

[Eva]

With NPN/PNP buffers? How long was it? How much length added?
In my experience NPN/PNP buffers without base resistor can become erratic at high current, as the gate voltage temporarily swings below the source during fast "current transfer" process (OFF, or reverse recovery) and internal diodes in driver IC clamp the drive output (base) to source potential, so the gate can get charge momentarily dumped into it when the expected situation is charge being removed. The base resistor in the NPN/PNP buffers limits base current in this case.

In other words, the problem with the output resistance built into gate driver ICs is that it has inherent clamping diodes to gate drive rails. And in high current high speed switching gate swings momentarily below source.

This is the reason IR engineers left the location for the resistor, although in this application it might not be needed. A trap for copiers too haha

 

[soky7]

I implemented 4R7 resistors Rb for driver and Rg for mosfets, but Mosfet were hot, and current consumption on rail voltage was 200mA, without resistor is 100mA, I dont now what is better combination Rb=4R7 and Rg=0R or vice versa,

 

[Eva]

Reduce turn off Rb, since some is built into the FETs, about 3r for IRFB4227 as far as I remember. Semi-resonant gate turn off gives lowest off losses, but slightly higher delay. IRFB4227 can pass enough current to get the negative spike problem. Check this post (do not use so much resonance for class D): http://www.diyaudio.com/forums/class-d/309168-ebay-amp-500w-believable-2.html#post5114036