Sunday, February 24, 2013

N-Channel MOSFET High-Side Drive: When, Why and How?


I had previously shown how to drive N-channel MOSFETs in low-side configuration. You can find the tutorial here:

http://tahmidmc.blogspot.com/2012/12/low-side-mosfet-drive-circuits-and_23.html

I’ve been requested to write a tutorial/article regarding high-side MOSFET drive. So, here I’ll talk about N-channel MOSFET high-side drive.

Let’s first look at the common low side configuration.

 Fig. 1 - N-channel MOSFET configured as low-side switch

Now let’s look at a MOSFET configured as a high-side switch.

Fig. 2 - N-channel MOSFET configured as high-side switch


You can quite easily see the difference between the high-side configuration and the low-side configuration. In the low-side configuration, the load is connected between the drain and +V, while the source is connected to ground. Thus, the gate drive is referenced to ground. So by applying a voltage of >7V (for Power MOSFETs) or >4V (for Logic Level MOSFETs), the MOSFET can be fully turned on.

Now let’s talk about the high-side configuration. The load is connected between the source and ground with the drain connected to +V. Thus the gate drive is not referenced to ground as source is not connected to ground and gate drive is related to VGS (voltage at gate with respect to source). I’ll talk about this in a while.

The difference in operation for the MOSFET configured as high-side switch as opposed to the MOSFET configured as low-side switch is that, it acts as a current source whereas the MOSFET configured as low-side switch acts as a current sink.

Now let’s go back to the high-side drive. Let’s say you apply a voltage of 12V (with reference to ground) to the MOSFET gate. However, when the MOSFET is on, voltage at source is equal to +V. Let’s assume +V is +15V. Now the problem is +12V gate drive (with reference to ground) will not keep the MOSFET on. When the MOSFET is on, the MOSFET source will be at a potential of +15V. To be on, the MOSFET must have +8V VGS minimum. So, if source is at +15V, the voltage at the gate with respect to ground must be at least +23V. If source was at +300V, for example, gate drive would require a minimum of +308V with respect to ground. This is if the gate drive is referenced to ground. If you have a separate isolated power supply whose ground and the ground of the MOSFET-based circuit are isolated, then  you can use that to drive the MOSFET as well.

There are quite a few ways to drive MOSFETs in high-side configuration. The first thing that might come into the minds of many of you would be a boost converter circuit or a charge pump circuit to use as the drive voltage for gate drive. This concept is sometimes used and isn’t wrong. However, it is usually used when voltage gap between control circuit voltage and gate drive requirement is small. If you needed to step up voltage from 12V to 40V for example, you might be able to accomplish it quite easily. However, a problem arises when there is the need to step up voltages from 12V to, say, 300V. In such situations, other solutions must be sought.

One simple solution is to use a gate drive transformer. This is not a method I prefer and thus I will not talk about it here. If you are interested, I might write another article just for gate drive transformers.

Another solution is to use a separate/isolated power supply whose ground is separate from the ground of the MOSFET-based circuit. See Fig. 3 below.

The other popular method is to use bootstrap based drive. In this drive method, a capacitor is charged to the required VGS – let’s say 10V – when the MOSFET is off. Then this capacitor is used during driving the MOSFET to provide an additional 10V over the source.

First I’ll talk about the use of a separate/isolated power supply. Here’s a circuit diagram illustrating this:

Fig. 3 - Driving a high-side N-channel MOSFET from a separate/isolated power supply (click image to enlarge)

When a logic high is given to “Drive Signal”, potential at optocoupler pin 4 (emitter of optocoupler transistor) is about +12V with respect to the ground / negative terminal/point of BAT1 – the separate/isolated power supply. This point is connected to Q1 source. Thus Q2 turns on. About +12V, with respect to Q1 source, is provided to Q1 gate. Thus Q1 is driven on.

When a logic low is given to “Drive Signal”, optocoupler pin 4 (emitter of optocoupler transistor) is at the same potential as the ground / negative terminal/point of BAT1 – the separate/isolated power supply. So Q3 turns on and pulls Q1 gate low. Thus MOSFET Q1 is driven off.

Note that the optocoupler ground is the same ground as the ground of the MOSFET-based circuit.

Here’s the current flow for when the “Drive Signal” is a logic high.

 Fig. 4 - Current flow when driving a high-side N-channel MOSFET on, from a separate/isolated power supply (click image to enlarge)

This driver can be used for any duty cycle – all the way from 0% to 100%. The driving frequency is limited by the speed of the optocoupler. For high frequencies, optically isolated MOSFET drivers may be used instead of the two transistors and the optocoupler – the optically isolated MOSFET driver will be all that’s needed. Some such drivers are TLP250, TLP350, HCPL3120, etc.

Now let’s talk about the boostrap based drive. Here when the high-side MOSFET is off, a capacitor is charged from the driving voltage. The capacitor charges through the load or a supporting low-side MOFSET. When the high-side MOSFET is to be turned on/driven, the voltage on the capacitor is used to drive the high-side MOSFET. Thus the limitation of this method is quite obvious. A large enough capacitor should be used for storing the required energy/charge for keeping the high-side MOSFET on for the required time. At the same time, the capacitor must be large enough that during the entire driving time, the voltage doesn't fall below about 8V, in order to prevent the MOSFET from being only partially on. Thus, the bootstrap based drive can not be used for 100% or close to 100% duty cycle. And the lower the frequency of operation, the larger the required capacitance.

The easiest way to drive a MOSFET using the boostrap based drive is to use a dedicated high side MOSFET driver. Some drivers come with just the high-side driver while many come with both high-side and low-side drivers. IR2117, for example, is one driver that contains a single driver that can be used to drive a high-side MOSFET driver. IR2110, which is arguably the most popular high-low side MOSFET driver, features a high-side driver and a low-side driver in a single device. I’ve written a detailed tutorial regarding the use of IR2110. Here's the tutorial:

http://tahmidmc.blogspot.com/2013/01/using-high-low-side-driver-ir2110-with.html

Besides the IR2110, there are many high-low side drivers available. L6385E and NCP2181 are my personal favorites. You can choose from a wide range of high side and high-low side drivers.

No matter which method you choose, once you know how to handle the drive requirement, it's really easy. In most cases, I use the bootstrap based drivers, although I do occasionally use isolated power-supply based drive. None of these methods are too difficult and I hope I've managed to provide you a clear answer to your question: "Why are high-side N-channel MOSFETs to be driven differently from low-side N-channel MOSFETs, and how do we drive the high-side N-channel MOSFET?" Do let me know your comments and feedback.

90 comments:

  1. hi thahmid great explination and well done.
    i haven't any doubt because your explination was covered all area .
    but i have two request .

    1-Can u explain about Transformer driver ?

    2-Can give a detailed calculation method to find
    Gate current, then only we can select the
    proper driver for each load /frequency[pwm].

    ReplyDelete
    Replies
    1. Hi,
      I'm glad you found my tutorial helpful.

      I'll work on those mentioned topics and will post them in the near future.

      Regards,
      Tahmid.

      Delete
  2. Working great friend



    I am getting lot of information from you...such as IR2110 ...ferrite core transformer and much more thanks for sharing..........



    --regards

    ReplyDelete
  3. bro i am using irf 740 and mct 2 e as isolater timer circuit to produce 75%duty cycle mosfet all 4 r n channel but they r not withstanding voltage they r getting burnt pls help me out soon

    ReplyDelete
    Replies
    1. Use MOSFETs with high enough voltage rating. Also, make sure you take care of any spikes and transients. Eg if you have a motor, when the motor turns off, if you don't have any freewheeling diode/circuitry in place, the spike from the motor will damage your MOSFET.

      Regards,
      Tahmid.

      Delete
  4. i want to remove speed v/s char of dc motor upto 220v

    ReplyDelete
  5. HI, i have implemented the circuits for testing high and low side, as you have shown on others links for ir2110. I am getting correct signal LO relative to the LIn. But at HO I am getting constant 12v for square wave Hin of 6v at 1khz. where i am doing mistakes ???

    ReplyDelete
    Replies
    1. To measure the signal at HO, what you need to do, is to remove the drive connections to the MOSFETs and connect VS to ground. Then check the signal at HO. If you see the correct signal, remove the connection from VS to ground and then connect the MOSFETs.

      It is due to the virtual ground (VS) that your oscilloscope does not properly detect/display the signal.

      Regards,
      Tahmid.

      Delete
  6. HI,
    I wanted know which device I can use for following requirements:
    -: Single high side mosfet
    -: TO-220 (5leads) package
    -: Pin configuration:
    1 - circuit common ground
    2 - input
    3 - battery
    4 - status
    5 - load
    please help me out with this... :

    ReplyDelete
    Replies
    1. I don't quite get your question. Could you clarify?

      Delete
  7. HI Tahmid, You are doing really appreciable work.

    I have a query.

    I need to generate 600 V dc from a 12 V battery. So I want to use a square wave MOSFET inverter to convert 12 V dc to 12 V ac. I am not using sine-wave inverter because I don't have to run any appliances. After that I will use a high frquency ferrite transformer to get 600 V ac from 12 V ac . Finally I will rectify & filter it to get 600 V dc.

    Can I use PWM to control the voltage of the square wave inverter? The output of inverter goes to transformer. Is it okay for the transformer to get a PWM input? If yes then what should be the range of duty cycle of PWM?

    ReplyDelete
    Replies
    1. Yes you can use PWM to control the voltage of the square wave inverter. Yes, it is ok for the transformer to get a PWM-ed signal. In fact that's what ferrite transformers get all the time. You should be good with a frequency between 30kHz and 60kHz. The duty cycle will vary depending on your transformer winding ratio and will control the output voltage.

      To control the output voltage using PWM, take feedback from the output side (remember to convert to DC and scale down).

      Regards,
      Tahmid.

      Delete
  8. Thanks a lot. It is difficult to get nicely explained topics on internet but your blog posts are nicely done.

    ReplyDelete
  9. HI TAHMID ,

    i want your help, i am designing an smps in half bridge, just like the old AT smps not having any auxilary supply, i want to use pulse transformer to drive Mosfets, mosfets are IRF840, power is approx 250 w 28V @ 9 - 10Amps for battery Charging .

    please help

    Sukhpreet

    ReplyDelete
    Replies
    1. Hi,

      Where are you stuck right now? Which specific part do you need help with?

      Delete
  10. Hello Tahmid,

    I found your schematic to be very useful in designing a circuit for a 48V battery charger. Thank you very much. Good luck in your studies.

    ReplyDelete
  11. Hello Tahmid, i wander, if i have transformator for drive circuit, and i drive mosfet who control 300V not same ground, can it be done like this with optocupler with same ground as battery +12V ?

    ReplyDelete
    Replies
    1. I don't quite understand what you're trying to say. A circuit diagram illustrating what you mean, would be nice.

      Regards,
      Tahmid.

      Delete
  12. please, can you add the Current flow when driving a high-side N-channel MOSFET off, from a separate/isolated power supply. like the one on Fig. 4

    ReplyDelete
    Replies
    1. I will add a diagram. But for now, the idea is that, when the MOSFET is to be driven off, the LED side of the optoisolator is off. Q3 turns on, pulling the gate of Q1 low. Thus the MOSFET is off.

      Regards,
      Tahmid.

      Delete
  13. Very useful information . Thanks very much

    ReplyDelete
  14. Great stuff, best I have found :) Wondering just one small thing...On the opto isolated drivers like the TLP250 you mentioned, Is that all you need is the power supply to the driver and the driver does the "bootstraping" internally? Or do you need an external bootstrap or voltage boosting in addition? Thank you

    ReplyDelete
    Replies
    1. If you have an isolated driver with the isolated power supply, no "bootstrapping" occurs. Bootstrapping is done only when there is no isolated power supply - to provide a "new" or "virtual" ground with which to reference (if thinking like that helps).

      The isolated power supply provides the gate voltage (with respect to source) required to drive the MOSFET.

      Hope that helps.

      Regards,
      Tahmid.

      Delete
  15. Hello Tahmid,
    I would like to ask about the configuration when using HCPL3120. I have tried supply the 3120 with isolated source, R2 = 10R, R3 = 1k, and the 2 transistors were skipped, the mosfet I used was IRFP460A, VCC for the mosfet is 24V and the load is 270ohm just for demo. Unfortunately, the voltage between drain and source pin was not square like the input, it had the straight rise-up and down but had curve like sin wave at the top and not stable. I think that is the result of not sharing the same ground (or I have done something wrong). Could you help me a little bit? And what happens if the optocoupler ground is not the same ground as the ground of the MOSFET-based circuit?

    ReplyDelete
    Replies
    1. The optocoupler must NOT have the same ground as the MOSFET ground if you're driving a MOSFET in high-side configuration.

      What is the voltage rating of the isolated source you are using?

      Delete
    2. The voltage rating of the isolated source I used for the HCPL3120 was 24V, because the VCC - VEE has to be bigger than or equal 13.5V. And the ground I mentioned was the ground of the cathode of the HCPL3120. Can it be different from the ground of the source that supplies to the drain terminal?

      Delete
    3. This comment has been removed by the author.

      Delete
    4. I have tested with Optocoupler like 4N35 and TLP521-2 and the circuit worked fine with the frequency below 2kHz. But if I raise the frequency up, it starts to curve on the way down
      I would like to work with higher frequency from at least 25kHz to 300kHz, that why I used HCPL3120. But the HCPL gave out the waveform with the top happening to be like a sine wave and not very stable.

      Delete
  16. This comment has been removed by the author.

    ReplyDelete
  17. Hi Tahmid,

    Great Explanation.

    I want to drive IRF840 at the frequency of 22Khz when load is connected and at lowest possible frequency (say about 250Hz) when load is disconnected. Please suggest me exact values of bootstrap components or give me the calculations.

    Regards,
    Ratish

    ReplyDelete
  18. Hi,

    Thanks a lot for sharing Tahmid! and very well explained!

    I'm not an expert on electronics, though I do small things with atmegas and such.

    I'm willing to build and test this circuit (together with some of your circuits on low-side switching back in your other post), to build a three-phase bridge to control a photocopier's a brushless motor with an atmega (I know I should add diodes in series with the nmos to cancel voltage spikes from the windings).

    I just wanted to confirm that `BAT1' can be replaced by a 220v->12v transformer + rectifier bridge + smoothing capacitors + lm7812, and wanted also to ask if `BAT1's circuit is actually isolated, as it connects to the load under the nmos (wouldn't it's ground be then connected to the load's ground?).

    In my case, I will initially test the circuit with 24V/3A, but would also like to use it in a future with an AC induction motor (220V) I have laying arround (very small, like 3/8 HP, I'd say), so just checking I won't fry anything.

    Thanks, and I wish you all the best, and that you keep sharing knowledge as your studies/life allows you so.

    ReplyDelete
  19. hi
    i used ir2117 to drive mosfet for dc dc buck converter the input for the driver is pwm from microcontroller i attached the circuit but there is a problem the output from this driver is 9v pure dc not pwm like the input
    http://www.edaboard.com/thread310188.html#post1327298
    need your help
    thanks

    ReplyDelete
  20. Hi Tamid,
    any clues on how to use the opto's in h bridge config?

    ReplyDelete
    Replies
    1. Use one per MOSFET. The two high side MOSFETs should have separate isolated power supplies while the low side MOSFETs can have the same power supply. Alternatively, you can create a capacitor-based bootstrapping-based driver for the high side MOSFETs and only one power supply. Alternatively again, you can create a separate charge-pumped (boosted) voltage to use to drive the MOSFETs - this is easier to achieve for low voltage drives compared to high voltage drive.

      Delete
  21. If the isolated battery and the mosFET grounds are isolated how come the current flows into the nMOS ... what I mean to say is "the circui is not complete"
    Please explain it to me

    ReplyDelete
    Replies
    1. The circuit is complete. There are just different current paths. Remember that the MOSFET is an insulated gate device. So, there's a current path to drive the gate. And there's another current path which is the main high current path.

      Delete
  22. hi ,
    im doing a circuit design on proteus . it is a dc-dc converter circuit and it is feedback using PIC16f877A to drive the pwm to the mosfet. but i really face difficulties in driving the mosfet and i came across to know optocoupler. i think mayb optocoupler might help to drive the mosfet. since i totally new in optocoupler (i just knew it today), can i send you my circuit and really appreciate for your help in figuring how should i make the mosfet work perfectly for my circuit. thanks!

    ReplyDelete

  23. I have a microcontroller (PIC16F1825 IOH = 3.5mA, VDD = 5V,IOL = 8mA, VDD = 5V) with output PWM driver signal that is:

    V = 0-5 V
    f = 20 kHz

    I have to drive a DC MOTOR with:

    Val = 12 V
    Imax = 40 A (inrush 150 A)
    locked rotor stabilized current: 50 A

    Is there a good combination Driver-Mosfet (high-side) for these specifications?

    For example if I take a MOS nchannel STB120N4F6 (Abs Max:Vds 40V, Id 80A,Rds 4mOhm)

    Do you know about efficient(>95%), robust and cheap enough solutions? Thanks

    ReplyDelete
    Replies
    1. Do you want to control both speed and direction? If so, you'll need the full-bridge configuration. Do keep in mind that you can't go to high duty cycles with a bootstrap-based high-side driver. In that case, it'll be better to use an isolated power supply, or a charge pumped higher voltage power supply to drive it.

      If all you need is speed control, you can just have the MOSFET work in the low-side configuration with the motor between drain and supply voltage. Remember the anti-parallel diode across the motor.

      Delete
  24. hai this is Mani i need gate driver circuit for Mosfet for BUck converter can u help me please...

    ReplyDelete
  25. Hi, very informative, thank you.

    ReplyDelete
  26. thank u Tahmid for ur explanation but i want u to draw a pratical circuit using component on how to get that isolated power supply Bat1 to run the totem drivers. Thank u for ue help because this high side drive is really a big problem to me sir. Thanku

    ReplyDelete
    Replies
    1. If you're running off of the main power supply, you can use a transformer isolated push-pull converter to generate multiple isolated voltages on the secondary. Rectify and filter these at the output and regulate if necessary. Then you can have as many isolated supplies as you need.

      Delete
  27. what are the worst case parameters for duty cycle accuracy when the frequency is constant, load is varying between 1% to 100% full load and duty cycle is varying from 10% to 90%?

    ReplyDelete
  28. Hello Dear Tahmid ;

    I've sent an email to you about my question but you have not still responded it yet :) Anyway,i have questions for you :

    1) I have 24V 3 Phase BLDC motor 120W i tried to control it with IR2110 but i did not understand when i applied to 1V to its VDD pin it draws approximately 500mA !! Most probably it shorted out somewhere in the circuit but did not find :S Also, i need almost full range of pwm for speed control so should i use ir2110 for driving this motor ?

    2) Or, i have tlp250. Should i use it for driving ? I have msp430f series which has output 3.3V and as you said in different subject that at least 4V supply is suitable for IR2110 series to arrange the logic threshold but you did not suggest this way. Therefore, i want to use tlp250 but is it required using external BJT as you used in Fig 3. ?

    3) When i will use 48V 1.2kW motor this tlp250 method is still applicable ? Also, i want to replace high side fets into IGBT ?

    Thanks in advance

    Regards

    ReplyDelete
    Replies
    1. 1) You probably have a short. If you need high duty cycles, you can't use bootstrapped high-side drivers. Look into using isolated power supplies.

      2) TLP250 is designed for driving the MOSFET so you don't need external BJTs.

      3) What frequency?

      Delete
  29. Hello Tahmid ;

    4) Why did not you use diode parallel with 10ohm resistor placed in gate as you used in your IR2110 application ?

    5) Should i use flyback diode or snubber circuit or diode i don't know exactly what the purpose does it use with my bldc H-bridge circuit ?

    6) Should i use parallel electrolytic or other type capacitor between high side N-fet drain to Low side N-fet source actually between the power supply vcc to gnd ? If yes, should i use it for each column (3 column 1 high 1 low to drive 3 phase) ?

    I want to explain each question briefly im sorry if i exaggerated the explanations :S

    Thanks in advance.

    I'm also the owner of the upper questions forgot the ask these :)

    Best Regards


    ReplyDelete
    Replies
    1. 4) You can use it if you want faster discharge.

      5) MOSFETs have body diodes that will serve that purpose. You'll want to use external diodes if you want lower conduction losses than the body diodes. You might need a snubber circuit.

      6) One should be okay. Make sure it can handle the ripple current.

      Delete
  30. Hello, I use IR2110 to control power mosfet to power a three-phase brushless motor. I have to run the engine for a start. I mounted a charge pump that provides a voltage of 30V to VB. VCC = + 15 = Vmot= + 24
    Every time I turn on the circuit the engine will not start: I lightly touch the tree to start working.
    Can anyone help? thanks Luciano

    ReplyDelete
  31. Hello, the circuit works, but there is a problem, the Q3 will not turn on. You don't have a valid -Vbe. The Q1 gate will discharge through R3 but not fast enough. Did you tested this circuit?

    Cheers

    ReplyDelete
  32. hey man , just a quick question :D ,
    I am building this circuit : http://www.lammertbies.nl/electronics/PI_metal_detector.html
    and i was planning on using mcp1407 but had no luck finding it, i could only find the ir2110, but have no idea whether to use it in high or low side config. do you have any idea what config. would work by looking at the schematic ? the gate driver is supposed to be connected to an arduino , thanks !

    ReplyDelete
  33. I'm new to electronics and mosfets.

    N-channel for high side switch is possible as you described,
    but isn't P-channel mosfet more suited for this task? In this case there are less complexity and component count.

    By what motivations should I choose to use N-channel mosfet for high side switch ?

    ReplyDelete
    Replies
    1. One huge advantage in using N-channel MOSFETs as opposed to P-channel MOSFETs is that the conduction losses are much lower for similarly priced devices. Another disadvantage of P-channel MOSFETs is the much lower availability and higher cost at high voltages.

      Delete
    2. Thanks! Good to know different aspects.

      Delete
  34. Hi Tahmid,

    Your article has helped me a lot already, I'd like to use dual N-Channel MOSFETs as a high side AC switch. Can I ask, could the 'BAT1' supply be a switching power supply 230VAC --> 12VDC which is powered from the main supply that will be switched. (i.e. does a switching power supply provide enough isolation from the main supply to be switched)

    Thanks in advance!

    ReplyDelete
  35. Hi Tahmid
    i want to use n-ch mosfet as switch in high side , i want to be on in long time or off in long time, (manual switch , not pulses)
    can i use it ?

    ReplyDelete
  36. Hi Tahmid
    Am working on DC-DC converters, in my converters two mosfets are there, one is high side and one is low side. I have to turn on two mosfets with same duty simultaneously is that possible by IR2110. Am generating pulses from TL494 and giving similar pulses to Lin and Hin. will i get same pulse at Lo and Ho.

    ReplyDelete
  37. great article.

    ReplyDelete
  38. I want to use IR 2110 to drive one low side MOS and one high side MOS. However, the gating signal for both the switches will be same. That means when the low side MOS is "ON" the high side MOS will be "ON" as well and vise-versa. Would you kindly help me in this regard?
    Can any one help me on this

    ReplyDelete
  39. Hi, I just want to know about a h bridge inverter circuit in which I can give driving signals to both High side and Low side without using a driver Ic..

    ReplyDelete
  40. Hi, is there an IC in the market that incorporates both the optocoupler and the high and low side gate driver?

    ReplyDelete
  41. From my understanding of your explanation mean they are all mosfet drivers but TLP250 will be best to IGBT transistor.

    ReplyDelete
  42. From my understanding of your explanation mean they are all mosfet drivers but TLP250 will be best to IGBT transistor.

    ReplyDelete
  43. I need a embedded mplab code for generating 10 different pulses for 10ms delay. pls can any one send me the source file... it will be very useful for me....

    ReplyDelete
  44. Tahmid you're the guy.
    Congratulations for your work, my knowledge about analogue electronic is not very well, but you are giving me a lot of it by sharing your knowledge.

    I am pleased to met you and your work, it is an honor for me.

    Keep going.

    regards

    Paulo

    ReplyDelete
  45. Vai, onek upokar hoilo, jibone prothom aj bujhlam - Ground Isolation ar subidha !
    Atto bosor kau shikaite pare nai, ami nijeo bujhi nai ! Aj shiklam- Thankyou !
    Cha re dawat roilo apner jonno !

    ReplyDelete
  46. Hi Tahmid, i have one problem at HO pin the amplitude of my output is continuously decreasing what should i do for that.

    ReplyDelete
  47. hello tahmid, my issues now with this design is that i dont want to use an isolated power supply because i am using the circuit as an Solar MPPT charger. please help with the non isolated high side driver. thanks

    ReplyDelete
  48. Hi Tahmid

    How would you approach designing a buck converter with Vin = 1170V and Vout = 370V. I am using a SiC high side FET and am having issues finding a good combination with a gate driver. what do you suggest?

    Donna

    ReplyDelete
  49. I have some doubts in separate/isolated power supply circuit

    what is maximum power supply voltage supply can be given to power supply main. is it possible to switch +220v dc using this circuit.

    ReplyDelete
  50. Hi,
    can i use HPCL 3120 driver to drive the MOSFET with 200 KHz? please help me in this regard.

    Thanks in Advance

    ReplyDelete
  51. what are the other high and low side drivers apart from ir2110 for driving a simple h-bridge inverter(full bridge)??..My circuit details are input voltage 36V
    Load resistance 20ohms LC filter values 200micro henry and 10 microfarad

    ReplyDelete
  52. Hi,
    I a Mechanical Engineer, currently working on Regenerative braking with BLDC.
    Trying to use N channel mosfets as high side switches. Being new to electronics, its really messing my mind haw to make that bootstrapping capacitor circuit.
    Isnt there any earier option? Like cant I but the bootstrapping circuit completely with capacitor fixed to it, so that I can plug it on before my Power mosfet?

    Need serious help, and urgently.
    Need to take and show readings within 3 days..
    Any help is highly appreciated.

    ReplyDelete
    Replies
    1. Cant I find the ready made circuit for the capacitor circuit?
      Too many typo error, sorry

      Delete
  53. Hi Thamid, I looked at your post and took great help. I understand how this bootstrap circuit works, but i 've some problem in the practical realization, so i hope you can help me by answering these questions. In particular i'm using L6385e which you said to be your favorite choice:
    1) Could I use it to drive single N channel MOS of buck converter which drive rotor and stator (two buck) of dc motor?
    2)I read on your other post in a forum but i am not sure to understood that could be problem in this configuration, in particular referring to the fact that the load should be shorted to zero potential to allow capacitor's charging, so there is something i must be aware?

    Thank you very much

    ReplyDelete
  54. Hello Tahmid, I am having dificuilty in driving the H-Side N-Channel MOSFET using Optocoupler Based Gate Driver ACPL-33KT of Avago Technologies Using Isolated Power Supply, the low-side MOSFET turns fully ON for Vgs about 8V for all power voltages , but when the power side voltage is increased above 12V, we find that the Vgs is only 5V and even then the Pulse is intermittent, when we increase Optocoupler Vcc , Vgs is increasing but Optocoupler Max Vcc is 20V, So can you suggest if bootstrap circuit is necessary even if we are using isolated supply for High-Side Gate Drive, and how to select Bootstrap Capacitor, is it just a dependant on Qgate Value from MOSFET Datasheet

    ReplyDelete
  55. hello guys, i just have a question that i need help with. i have an inverter that outputs a 240 V ac signal. i need to display the power thats output on an LCD. do i need to make use of current and voltage sensors and if yes, how and where do i use them and to what do i connect them. thanks in advance

    ReplyDelete
  56. hi sir tahmid. i am working on my program to drive a single phase induction motor but my problem is that i cant generate a sine wave output at the inverter part. i am using an opto coupler as a driver circuit and an n-channel mosfet. can you help me out with a circuit?

    ReplyDelete
  57. Hi Tahmid, thank you for sharing your knowledge. I'm pretty new to this, so i most probably missed something. Can you please tell me how Q3 turns on. To me it looks like if the signal is low, the opto is open. How is Q3 going to conduct then. Thanks

    ReplyDelete
  58. Hi .. tahmid , Iam using IR2117 to drive the mosfet in buck converter , At no:2 pin i have given a PWM signal with avg voltage of about 6 volts and max about 12 volts , but at pin 7 or 6 there is no output .. what could be the possible problem ???

    ReplyDelete
  59. Hi Tahmid
    I have one problem during implementing the same circuit.
    The circuit works well when i am using 12 volt battery to supply VDD but circuit does not work when i connected 220 volt dc to mosfet vdd.
    Why is we have to tied ac neutral to rectified voltage but in case of bridge rectifier it is not possible.
    Help me please i am in great trouble or share your email id so that i can mail you my problem.
    Thanks

    ReplyDelete
  60. Dear Tahmid i use TL250 to drive 1200v Module iGBT in my Buck converter for 360 v Batter charger , but some failures of IGBT and i see TL250 heating up a little more, what do u suggest mr Tahmid, ur suggestion will be higly appreciated

    ReplyDelete
  61. This comment has been removed by the author.

    ReplyDelete
  62. Hi, Tahmid.

    Can i use an L7812 instead of BAT-1 in the isolated power supply??

    ReplyDelete
  63. hi Tahmid, my name is Marco Petrolesi from italy, i've problem with a mosfet driver.
    I am using IR2117 to drive N mosfet (IRF540N) to build my buck converter.
    At pin2 i have given a square wave 100KHZ from PWM signal generator with 9 volts pk to pk.
    At pin 7 there is no output.
    The converter is powered by 48V power supply on the drain of mosfet, while source is connected at pin 6 of ir2117, at fast recovery diode and inductor, ecc.ecc.
    Nothing to do! no signal output!
    Sometimes only for 1/4 second i can see signal... after, nothing.
    Can you help me, please!
    I ask if you can write to my @mail address: petrolem2012@gmail.com
    tankyou
    Marco Petrolesi

    ReplyDelete
  64. I still dont get the point of using these drivers, like any real application?

    ReplyDelete