The mosfets are house numbered (75639) Intersil TO-247 type packages, driven by a HIP4080AIP.
Can I parallel a second set of four outputs to be able to run into a 1 ohm load? I have 2, 4ohm DVC subs so my choices are halve the output power of the amp at a 4 ohm load, melt it into a puddle of slag at a 1 ohm load, or find a way to make it do what I want.
I will be happy to supply any additional info needed to help.
Can I parallel a second set of four outputs to be able to run into a 1 ohm load? I have 2, 4ohm DVC subs so my choices are halve the output power of the amp at a 4 ohm load, melt it into a puddle of slag at a 1 ohm load, or find a way to make it do what I want.
I will be happy to supply any additional info needed to help.
Thank you for your rapid reply. I would of course love to have double the current over a 2 ohm load, but will be happy as long as I achieve approximately >=700w and it doesn't go China Syndrome on me.
What is the best method to insure the power supply can handle the increased current demands, and do I need to make other changes to the components that control the outputs?
I have much to learn yet.
Does anyone know of a cross for the Stillwater (Kicker) house numbered Intersil 75639?
What is the best method to insure the power supply can handle the increased current demands, and do I need to make other changes to the components that control the outputs?
I have much to learn yet.
Does anyone know of a cross for the Stillwater (Kicker) house numbered Intersil 75639?
IVX, I found the datasheet. It seems that Fairchild is now manufacturing the HUF75639G3. I was able to find both the Intersil and Fairchild datasheet's and compare them. The newer Fairchild datasheet looks to be an edited version of the original Intersil file.
I repair electronics for a living so I have gotten rather good at scrounging up information on obscure parts, but I was getting nowhere until you gave me the prefix of the part number. I don't know how you found it, but I thank you.
If I parallel another set of 4 HUF75639G3's to the outputs, will I gain anything? How about at the power supply where there are 6
HUF75639G3's in parallel, will I gain anything by adding more?
My intention is to lower the workload of the individual output by spreading the work out more. I am utterly ignorant of electrical design with MOSFETS, so I am wanting to know if I am on the right track here.
I repair electronics for a living so I have gotten rather good at scrounging up information on obscure parts, but I was getting nowhere until you gave me the prefix of the part number. I don't know how you found it, but I thank you.
If I parallel another set of 4 HUF75639G3's to the outputs, will I gain anything? How about at the power supply where there are 6
HUF75639G3's in parallel, will I gain anything by adding more?
My intention is to lower the workload of the individual output by spreading the work out more. I am utterly ignorant of electrical design with MOSFETS, so I am wanting to know if I am on the right track here.
SHOdown,
Next time try the search by google- "75639 TO220".
I repair electronics for a money, it's my stupid day job
Oops, you kicker have a H-bridge topology, so you really need to add four huf's(with gate(pin#1) resistor(same value as on the exist huf's) for each) else.
What about dc/dc convertor parameters: transformer dimensions&turns, mosfets type and quantity, rectifiers type, rails voltage?
Next time try the search by google- "75639 TO220"
.I repair electronics for a money, it's my stupid day job
Oops, you kicker have a H-bridge topology, so you really need to add four huf's(with gate(pin#1) resistor(same value as on the exist huf's) for each) else.
What about dc/dc convertor parameters: transformer dimensions&turns, mosfets type and quantity, rectifiers type, rails voltage?
Hi Ivan. I sure found it hard to survive repairing electronics for a living.
I ran into trouble when I paralleled MOSFETs by running separate gate resistors. When I tried doing it that way in my power supplies, I always got shorted MOSFETs. I found that I had to connect the MOSFET gates directly together after paralleling the resistors.
I wonder why it is commonly accepted to separate the gates of the parallel MOSFETs from each other. I am not certain of how the devices interact to self-destruct, but one reason push-pull topologies seem to survive the "normal" way is that the leakage inductance of the transformer buffers opposing devices from each other. I actually tried a totem pole this way--set up two transformer windings between the the MOSFETs. The MOSFETs did not blow when the gates were isolated. Unless maybe I just did this test on the simulator and am suffering from mental fog. But I certainly did do it with a standard push-pull circuit and the MOSFETs survived.
In a standard totem pole, I discovered that relatively large gate resistors are needed to prevent destruction unless the gates are connected together. Those are the results I found.
Best Regards
I ran into trouble when I paralleled MOSFETs by running separate gate resistors. When I tried doing it that way in my power supplies, I always got shorted MOSFETs. I found that I had to connect the MOSFET gates directly together after paralleling the resistors.
I wonder why it is commonly accepted to separate the gates of the parallel MOSFETs from each other. I am not certain of how the devices interact to self-destruct, but one reason push-pull topologies seem to survive the "normal" way is that the leakage inductance of the transformer buffers opposing devices from each other. I actually tried a totem pole this way--set up two transformer windings between the the MOSFETs. The MOSFETs did not blow when the gates were isolated. Unless maybe I just did this test on the simulator and am suffering from mental fog. But I certainly did do it with a standard push-pull circuit and the MOSFETs survived.
In a standard totem pole, I discovered that relatively large gate resistors are needed to prevent destruction unless the gates are connected together. Those are the results I found.
Best Regards
Actually, i'm too lazy and always use single mosfets,
but my repairing experience gave me many examples such implementations (i.e. unshorted gate nodes).
Any dc/dc push-pull convertor from the caraudio amps have same circuit.
About totem pole case see attached.pdf
I have bad feeling about paralleling mosfets generally, and can see only economical reason here, because irf640, irf9640 is pretty cheap.
but my repairing experience gave me many examples such implementations (i.e. unshorted gate nodes).
Any dc/dc push-pull convertor from the caraudio amps have same circuit.
About totem pole case see attached.pdf
I have bad feeling about paralleling mosfets generally, and can see only economical reason here, because irf640, irf9640 is pretty cheap.
Besides, there shouldn't be a need use more MOSFETs in a circuit than needed for the project. It is much easier to drill holes and mount two devices than four, also.
One reason car audio may get away with doing totem poles with separate gate connections is that the voltage across the MOSFETs is lower than rectified mains voltage. The result is that the internally induced voltage on the MOSFET gates is not high enough to cause them to cross the turn-on threshold during MOSFET switching.
The separate freewheel diodes may help also by helping to keep the slower recovering body diodes from turning on as hard or as long. Maybe, too, the pack IC softens the MOSFET switching to reduce transients and spikes. But, I think the reduced "Miller effect" as described in the previous paragraph is the main factor.
One reason car audio may get away with doing totem poles with separate gate connections is that the voltage across the MOSFETs is lower than rectified mains voltage. The result is that the internally induced voltage on the MOSFET gates is not high enough to cause them to cross the turn-on threshold during MOSFET switching.
The separate freewheel diodes may help also by helping to keep the slower recovering body diodes from turning on as hard or as long. Maybe, too, the pack IC softens the MOSFET switching to reduce transients and spikes. But, I think the reduced "Miller effect" as described in the previous paragraph is the main factor.
Hi,
Here's an app note to add fuel to this fire:
http://www.fairchildsemi.com/an/AB/AB-9.pdf
Come out fighting!
Here's an app note to add fuel to this fire:
http://www.fairchildsemi.com/an/AB/AB-9.pdf
Come out fighting!
Subwoofer, I am merely seeking to make changes to an already proven design, rather than starting from scratch. I am trying to beef up an amp designed to run at a 2 ohm load into one that can run into a 1 ohm load without killing it. I don't even necessarily care if I improve the power output (yeah right) but it has to run with a 1 ohm load.
but it has to run with a 1 ohm load.
SHOdown, my present impression is that the MOSFETs will be safer without the separate resistors, but I think it will be very important to just about touch the MOSFETs side-by-side to keep the ringing down. Keep connections as short as possible. I actually carefully bend the leads over to touch each other and then solder them together.
One thing going to your advantage is that for car audio, the lower voltage keeps the Miller Effect down so as to help prevent ringing from causing cross-conduction.
There may also be the possibility of lowering the power supply voltage so that the current through the MOSFETs is reduced into 1 Ohm. The feedback point in the switching power supply could be found and altered so that the feedback will occur at a lower voltage. If the power supply is 40 volts, it could be lowered to 25. Then be sure that the MOSFET drivers still get all the voltage they had at the higher setting.
Edit: So with the lower voltage, even using separate gate connections and resistors like in the diagram should also work, IMO.
One thing going to your advantage is that for car audio, the lower voltage keeps the Miller Effect down so as to help prevent ringing from causing cross-conduction.
There may also be the possibility of lowering the power supply voltage so that the current through the MOSFETs is reduced into 1 Ohm. The feedback point in the switching power supply could be found and altered so that the feedback will occur at a lower voltage. If the power supply is 40 volts, it could be lowered to 25. Then be sure that the MOSFET drivers still get all the voltage they had at the higher setting.
Edit: So with the lower voltage, even using separate gate connections and resistors like in the diagram should also work, IMO.
I need to learn the language. All these Miller effects, cross-conducts, and so forth are new to me, but I have been at this point with a thousand other topics during my lifetime so I know that soon I will understand. I just need time and information to learn.
I have learned a lot already thanks to you and Ivan.
Keep pushing the information this way and I will gratefully absorb it as quickly as I am able. If I can not respond right away though, please do not take that as a lack of interest in the help I have been receiving. I greatly appreciate every word that everyone has taken the time to write, and for the links to further information that others have included.
I have been astounded at the level of response to my question, and by the overall quality of intelligence and creativity here.
This is defiantly the place for me; I feel very much at home here.
I have the sense that I am not the only one here who is driven to learn as much as possible, or to do things just to see if they can be done.
I have learned a lot already thanks to you and Ivan.
Keep pushing the information this way and I will gratefully absorb it as quickly as I am able. If I can not respond right away though, please do not take that as a lack of interest in the help I have been receiving. I greatly appreciate every word that everyone has taken the time to write, and for the links to further information that others have included.
I have been astounded at the level of response to my question, and by the overall quality of intelligence and creativity here.
This is defiantly the place for me; I feel very much at home here.
I have the sense that I am not the only one here who is driven to learn as much as possible, or to do things just to see if they can be done.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.