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Any beefy coil driver chips?

J

Joerg

Jan 1, 1970
0
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.
 
J

Jim Thompson

Jan 1, 1970
0
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.

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
 
J

Joerg

Jan 1, 1970
0
John said:
It would be pretty simple to use a power mosfet and a
quad-nand-schmitt, HC132 maybe, to make a blipper/PWM driver. Cheap.

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 ...
 
J

Joerg

Jan 1, 1970
0
Vladimir said:
There are *many* high/low side automotive switches made by Infineon,
IRF. They are very robust and protected from anything, and typicaly
rated over 48V. However they are slow so the PWM rate can't be higher
then several kHz.

Those "several" kHz will be a wee problem.
 
J

Jim Thompson

Jan 1, 1970
0
Well, I know how to do it in discretes but was hoping there'd be a chip
with most of this in there :)

"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
 
P

Paul Keinanen

Jan 1, 1970
0
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.

Have you looked at CRT vertical deflection (PWM) drivers or are they
already too specialized ?

Paul
 
J

Joerg

Jan 1, 1970
0
John said:
One HC132 section will do that.

With a Schmitt? I haven't gotten that far yet but have done amps with
regular CD4000 inverters. Still, that'll be another chip.
plus a SVS so the FET doesn't go

What's an SVS?

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.

numerous resistors, and so

One HC132, 2 or 3 Rs, 2 Cs maybe, if I understand what you want to do.

Cheap.

Cheap yes, but eats real estate.
 
J

Joerg

Jan 1, 1970
0
Jan said:
Since I did the PWM SEPIC with one PIC and one power MOSFET,
I would have a go with a PIC and maybe 3 resistors...
decoupling cap too.
Maybe the PIC can take over functons of other things on the board too.
That is usually where the advantage is,


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 :)
 
J

Joerg

Jan 1, 1970
0
Paul said:
Have you looked at CRT vertical deflection (PWM) drivers or are they
already too specialized ?

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

Joerg

Jan 1, 1970
0
how about a steppermotor driver? something like L6207 or L6506 + fet

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.
 
J

Joerg

Jan 1, 1970
0
Jan said:
Since I did the PWM SEPIC with one PIC and one power MOSFET,
I would have a go with a PIC and maybe 3 resistors...
decoupling cap too.
Maybe the PIC can take over functons of other things on the board too.
That is usually where the advantage is,


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.
 
J

Joerg

Jan 1, 1970
0
Jan said:
That is easy to solve, drive the MOSFET gate from the incoming voltage,
and while the PIC starts up in *microseconds* have it do the pulldown
thing on the gate,
As the PIC is high impedance output while not initialized, all you need is a pullup
resistor on thte PIC output.
You need a resistor to ground otherwise... for the same reason:
intintial floating ouput pins.

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?
 
J

Joerg

Jan 1, 1970
0
Jan said:
Only when many kHz, I have it drive a MOSFET at about 19kHz directly.
How high a frequency does a solenoid need? Not much I suppose?

19kHz would suffice here.
Yea, take no chances, PIC may present problems if you are not very used to it.

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 ;-)
 
J

Jim Thompson

Jan 1, 1970
0
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.

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
 
J

Joerg

Jan 1, 1970
0
John said:
Then program one of those SOT-23 PICs.

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.
 
J

Jim Thompson

Jan 1, 1970
0
In the single-digit milliseconds :-(

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
 
J

Jim Thompson

Jan 1, 1970
0
In the single-digit milliseconds :-(

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
 
J

Joerg

Jan 1, 1970
0
Jim said:
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 ;-)

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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