H-bridger motor driver,Urgent Help is needed From Expert!!!

Discussion in 'The Projects Forum' started by chrislee84, Dec 31, 2007.

  1. chrislee84

    Thread Starter Member

    Dec 8, 2007
    14
    0
    Hi to all of u,

    I am doing a H-bridge motor driver for a PMDC motor which is 24V and have rated current 8.5A. I use 4 N-channel mosfet with a mosfet driver(HIP4080A, datasheet= http://www.intersil.com/data/fn/fn3658.pdf ).

    Inside the datasheet of the mosfet driver, there is a circuit which show the typical application of the mosfet driver. Thus, i follow the circuit show and try to do one without the bottom part which is the op-amp. But the result i get is not the H-bridge driver characteristic. 3 of the mosfet on at the same time and i can turn on one of the lower side of the mosfet.

    Who can help me???

    By the way, i want to ask whether i can use two dry battery(cadmium,12V and 7.2AH) in series for my 24V, rated current 8.5A PMDC motor???
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You cannot omit the op amp portion of the circuit. That is what gives the driver the feedback for the current being drawn by the H-bridge.

    The circuit is a general guideline, but you have to calculate the values for the various resistors. I have a strong hunch that you have not programmed HDEL and LDEL with the proper resistance values for your particular MOSFETs, but I can't determine that since you have not stated precisely which N-channel MOSFETS you are using. You'll need to determine your on-time and off-time delays for your MOSFETS by looking in their datasheets, and then look at Figure 32 in the datasheet to determine the value of resistance needed for HDEL/LDEL. Otherwise, you'll wind up with the shoot-through condition you're seeing. (IE: dead short between the high/low sides due to both high and low side on simultaneously.)

    You should post a schematic of exactly what you have wired up at the moment.

    If you try to use your two dry batteries to power the motor, they will become discharged in a VERY short period of time, and they may explode due to overheating, as the load that the motor will place on them will look almost like a dead short. This will cause the batteries to drop voltage across their internal resistance, causing them to rapidly heat up.
     
  3. chrislee84

    Thread Starter Member

    Dec 8, 2007
    14
    0
    Hi SgtWookie,

    This is the schematic i have connect, all the resistor i use are the 1.5 k ohm and the all the capacitor i use are 10 micro Farad.
    The 4 N-channel mosfet i use are IRFP 260N (datasheet=http://www.500kc.com/200w_amp/irfp260n.pdf)
    How do i determine the on-time or off-time? Do you have any guide?
    And the schmatic i connect now, do it have any problem because now i cannot swith on or control the H-bridge.

    [​IMG]

    Wait for ur reply. Thanks.
     
  4. chrislee84

    Thread Starter Member

    Dec 8, 2007
    14
    0
    Hi SgtWookie,

    Sorry, in the schematic i post up there, the voltage is 24V( is not 12V) and the load is the 24V, rated current 8.5A PMDC motor.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The on-time and off-times are on page 2 of the datasheet you provided.

    Turn-on delay time is 17ns
    Turn-off delay time is 55ns
    Now for safety, we can add in the fall time, which is 48ns
    So, total turn-off delay time is 55ns+48ns = 103ns
    Subtract the turn-on delay time: 103ns - 17ns = 86ns

    Looking in the datasheet for the HIP4080A, page 13, figure 32, I see that for a "dead time" of 90ns your HDEL/LDEL resistance must be 200K Ohms each.

    It is no wonder that you were having problems!

    But, that's not the end of your difficulties. You need to add that op amp circuit back in, along with the sense resistors. The sense resistors go between the drains of the lower half of the bridges and ground. They should be 0.1 Ohms or less, and must not be inductive type (wirewound). Even at 0.1 Ohms, you'll be dissipating roughly 7.3 Watts at 8.5 Amperes. You could use five 0.5 Ohm 2 Watt 5% carbon resistors in parallel to achieve the 0.1 Ohms.

    I can't spend much time on this today - but this circuit certainly needs more work.
     
  6. jaydag77

    Member

    May 28, 2007
    17
    0
    there is an 'open' project ongoing for a while now which uses this IC, you can probably find some good info and practical examples of its use there? OSMC is the project name, there is a yahoogroup which still gets a few hits now and then, I think the project has undegone pleny of revisions so I think is considered to be stable, but I haven't really delved into it...i was once considering using the hip4080 and/or a close cousin but that project never 'took'.
     
  7. chrislee84

    Thread Starter Member

    Dec 8, 2007
    14
    0
    Hi to you all,

    I m using HIP4080A IC (datasheet=http://www.ortodoxism.ro/datasheets/intersil/fn3658.pdf
    Application note=http://www.intersil.com/data/an/an9404.pdf)
    to do a H-bridge driver with along with 4 N-channel mosfet IRFP260N (datasheet=http://www.ortodoxism.ro/datasheets/irf/irfp260n.pdf).
    The actual load for my project is 150W, 24V PMDC motor with rated current 8.5A but now i m testing with a load which is a 20W, 12V power window motor because i scare the PMDC motor will burn in this testing stage.

    The schematic diagram is as below which i use to do the H-bridge now:
    [​IMG]

    The 2 diode in the diagram are IN4001A (datasheet=http://www.ortodoxism.ro/datasheets/dccomponents/IN4001A.pdf)

    The problem now i facing is when i connect all the component according to the schematic diagram, the 4 mosfet cannot be ON whether the IN- voltage is higher or lower than IN+ voltage. What is the problem???
    Are the HIP4080 mosfet driver IC is burn? How do i test it to make sure that the HIP4080 is still in good condition?
    Can someone HELP ME??? What is the roof that cause this circuit not functioning?
     
  8. chrislee84

    Thread Starter Member

    Dec 8, 2007
    14
    0
    Hi SgtWookie,

    I m using HIP4080A IC (datasheet=http://www.ortodoxism.ro/datasheets/intersil/fn3658.pdf
    Application note=http://www.intersil.com/data/an/an9404.pdf)
    to do a H-bridge driver with along with 4 N-channel mosfet IRFP260N (datasheet=http://www.ortodoxism.ro/datasheets/irf/irfp260n.pdf).
    The actual load for my project is 150W, 24V PMDC motor with rated current 8.5A but now i m testing with a load which is a 20W, 12V power window motor because i scare the PMDC motor will burn in this testing stage.

    The schematic diagram is as below which i use to do the H-bridge now:
    [​IMG]

    The 2 diode in the diagram are IN4001A (datasheet=http://www.ortodoxism.ro/datasheets/dccomponents/IN4001A.pdf)

    The problem now i facing is when i connect all the component according to the schematic diagram, the 4 mosfet cannot be ON whether the IN- voltage is higher or lower than IN+ voltage. What is the problem???
    Are the HIP4080 mosfet driver IC is burn? How do i test it to make sure that the HIP4080 is still in good condition?
    Can someone HELP ME??? What is the roof that cause this circuit not functioning?

    Hi SgtWookie, what is the sense resistor?
     
  9. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You don't have the load sense resistors nor the op amp in the circuit yet.
     
  10. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Look at my prior response.

    The current sense resistors go between the drains of the low sides of the bridge and ground. The op-amp takes that signal, adjusts it, and provides feedback to the HIP4080 IC; it tells the chopper circuit when to turn off the current to prevent burning your motor out.
     
  11. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
  12. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    I have merged the duplicate threads. Chrislee, please keep commentary and questions on this topic in one thread.

    And put the op-amp back in. The darn thing just won't work without it!!
     
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