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Any beefy coil driver chips?

Discussion in 'Electronic Design' started by Joerg, Jul 31, 2009.

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  1. Joerg

    Joerg Guest

    Need to drive a >30V (several amps) coil but back off once it's on to
    avoid a cook-out. This needs to be PWM'd because the drive electronics
    can't get hot at all. So I looked at coil driver chips. DRV103 and the
    like. Many can't stomach more than 32V which is borderline for me and
    the saturation voltage respectively Rdson values, well, yawn. Nothing to
    write home about.

    Did I miss a really good chip? Else I'll just roll my own.
     
  2. Jim Thompson

    Jim Thompson Guest

    See (from Nagle's teletype hammer driver request)...

    http://www.analog-innovations.com/SED/HammerDriver_RevD.pdf

    If you have trouble understanding it, let me know and I'll hold your
    hand ;-)

    ...Jim Thompson
    --
    | James E.Thompson, P.E. | mens |
    | Analog Innovations, Inc. | et |
    | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
    | Phoenix, Arizona 85048 Skype: Contacts Only | |
    | Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
    | E-mail Icon at http://www.analog-innovations.com | 1962 |

    I love to cook with wine Sometimes I even put it in the food
     
  3. Joerg

    Joerg Guest

    Well, I know how to do it in discretes but was hoping there'd be a chip
    with most of this in there :)
     
  4. Joerg

    Joerg Guest

    Yes, that plus an opamp for the PWM, plus a SVS so the FET doesn't go
    *PHUT* when the control voltage is sluggish, numerous resistors, and so
    on. Stuff kind of adds up and I'm cramped for real estate on this one.
    Maybe it's time for those SC75 and TSSOP packages again. I hate
    debugging such small stuf, but I guess man's got to do what man's got to
    do. Que sera, sera ...
     
  5. Joerg

    Joerg Guest

    Those "several" kHz will be a wee problem.
     
  6. Jim Thompson

    Jim Thompson Guest

    "High" voltage processes are getting rarer and rarer... they tend NOT
    to be economical solutions given the quality of discrete power
    devices.

    I just received an RFQ for a TRIAC-uP interface, powered directly from
    the line. I'll do it with a cheap 5V process and use two discrete
    TRIAC's.

    ...Jim Thompson
    --
    | James E.Thompson, P.E. | mens |
    | Analog Innovations, Inc. | et |
    | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
    | Phoenix, Arizona 85048 Skype: Contacts Only | |
    | Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
    | E-mail Icon at http://www.analog-innovations.com | 1962 |

    I love to cook with wine Sometimes I even put it in the food
     
  7. Have you looked at CRT vertical deflection (PWM) drivers or are they
    already too specialized ?

    Paul
     
  8. Joerg

    Joerg Guest

    With a Schmitt? I haven't gotten that far yet but have done amps with
    regular CD4000 inverters. Still, that'll be another chip.
    Supply voltage supervisor, basically to make sure that there is no gate
    drive until VDD has reached at least 10V. With some hysteresis on there.

    Cheap yes, but eats real estate.
     
  9. Joerg

    Joerg Guest


    I had thought about that as well but a uC ain't desired in this
    situation. Plus needs drivers for the FET gate. Oh well, guess I'll just
    do it discrete then. My old turf :)
     
  10. Joerg

    Joerg Guest

    They could be ok but they are just about ready to follow the dinosaurs,
    no market left for them.
     
  11. Joerg

    Joerg Guest

    Yes, those would be an option because some have a I-sense line and an
    enable that I could use for PWM. I am also looking at synchronous buck
    chips where I can unhook the look. But slim pickens at those voltage levels.
     
  12. Joerg

    Joerg Guest


    Forgot to mention one "minor" detail. I also do not have a supply
    voltage, just the on/off control signal with lots of amps (think
    industrial control gear). This excludes many uC and also stepper driver
    chips because they need several msec to boot, reset or prime a charge pump.
     
  13. Joerg

    Joerg Guest

    I don't know PICs, mainly just MSP430 and some 8051 variants. Don't they
    have a POR/BOR in there that takes its time after VCC gets applied?
     
  14. Joerg

    Joerg Guest

    19kHz would suffice here.
    I don't mind a new uC but there are some concerns as to the POR/BOR
    stuff in there. For example, all that TI says in their MSP430 datasheets
    is 2000usec max. That's a bit longish for this app, by that time there
    could be some smoke development ;-)
     
  15. Jim Thompson

    Jim Thompson Guest

    How much time between "thumps"?

    ...Jim Thompson
    --
    | James E.Thompson, P.E. | mens |
    | Analog Innovations, Inc. | et |
    | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
    | Phoenix, Arizona 85048 Skype: Contacts Only | |
    | Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
    | E-mail Icon at http://www.analog-innovations.com | 1962 |

    I love to cook with wine Sometimes I even put it in the food
     
  16. Joerg

    Joerg Guest

    Yes, very tempting, this is what Jan also suggested. Got to find out
    whether they make one that can wake up from zero power state in under
    100usec though, no internal POR/BOR and stuff or where I can disable
    that. But it needs to be for automotive temps and ideally mask
    programmable later.
     
  17. Joerg

    Joerg Guest

    In the single-digit milliseconds :-(
     
  18. Jim Thompson

    Jim Thompson Guest

    Trivial. Study what I posted. Long hold-up time. Easy to modify to
    your needs. NO PWM needed. Only inexperienced weenies think PWM...
    that's SO school-book and USELESS ;-)

    ...Jim Thompson
    --
    | James E.Thompson, P.E. | mens |
    | Analog Innovations, Inc. | et |
    | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
    | Phoenix, Arizona 85048 Skype: Contacts Only | |
    | Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
    | E-mail Icon at http://www.analog-innovations.com | 1962 |

    I love to cook with wine Sometimes I even put it in the food
     
  19. Jim Thompson

    Jim Thompson Guest

    Post your exact needs, and I'll sketch it out for you. (Initial
    current, holding current, etc.)

    ...Jim Thompson
    --
    | James E.Thompson, P.E. | mens |
    | Analog Innovations, Inc. | et |
    | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
    | Phoenix, Arizona 85048 Skype: Contacts Only | |
    | Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
    | E-mail Icon at http://www.analog-innovations.com | 1962 |

    I love to cook with wine Sometimes I even put it in the food
     
  20. Joerg

    Joerg Guest

    Ahm, don't conclude so fast. The coil cannot always be matched to the
    rail at hand, or shouldn't be. We ain't got no 120V in this here box. So
    the coil is meant for only a few volts, on purpose ;-)
     
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