Dimmable LED Driver to Modulate Resistive Load

The link seems broken here, also I would assume you mean "Inductive Load" ??

The ellipsis in you link above is not a shorthand for display, part of the URL has really been replaced with ..., so it doesn't work.

Jon

You just have to search for the file name. I got the data sheet.

This is kind of a weird LED driver since most are boost. Maybe there are products where they bus around 48VDC for lighting.

You do realize this is a switcher. If not, that could be a show stopper for your application.

If I had to venture a guess, I suspect the circuit looks like a hysteretic battery charger. But these aren't designed for much bandwidth, well since they are battery chargers. ;-) If a switcher is OK, maybe you could adapt some Class D audio power amp circuit. At least then you would know the bandwidth.

• The page cannot be found

Without a schematic, there's no way to guess how the device would behave with an inductive load. (Though my guess would be that it would behave as a current-source-once/smoke-mostly device :-)

For those who reported a "broken link", I looked at the data sheet, starting from the root, then searching for AA0593 >:-} Not a lot of information there.

You could "tune" the solenoid inductance, by the usual trick of paralleling with an RC, where...

RC = Lsolenoid/Rsolenoid

which can make the coil look like a "real" impedance, but there's still some risk.

Your solution could be to simply parallel a diode with the solenoid, so that "flyback" current is absorbed in the diode rather than trashing the LED driver. Depends on what you're trying to accomplish. ...Jim Thompson

--- No disrespect intended, but having asked the questions you did, you may have bitten off more than you can chew.

Can you tell us more about the equipment you want to calibrate and the properties of the magnetic field you want to generate?

-- JF

The impedance is a function of the movement of the armature. You can't tune it out with a cap.

My apologies for the non-working link.

Here is a good one with a summary. The full spec sheet PDF can be obtained by clicking the "downloads" tab.

Thank you for the responses so far.

Robert Leavy

The tests are on Hall effect geomagnetic sensors.

We have built a range of magnetic field generators, but the KC24W-700 LED driver appealed due to the relatively high voltage and current output obtainable, and that these could be modulated with complex low frequency signals from our lab arb gen.

Yes, I know there are other way to do this, but I was inquiring about this particular device since it seemed unique. IOW what does it need to see on the output side to perform to full spec and not be damaged.

The solenoid coils are typically air core. In the above case, we would use a resistance that would accommodate the full available current.

Here is a working link to the part's datasheet:

Robert Leavy

Miso misses the math, as usual, it's not "tuning". ...Jim Thompson

Anyone that does RF would tell you that you tune to get the load to look resistive.

Have you ever considered studying electronics?

Well, we call those inductors or antennas, but if you want to nitpick, you win. However, I bet the OP has an armature.

Anyone that does RF knows that you tune for minimum smoke...

My simple method makes inductive loads look resistive over a wide range of frequencies, up until inter-winding strays clean your clock. ...Jim Thompson

Wow. Where to begin? First a solenoid is NOT a resistive load. Misapprehension accumulates from there. Are you interested in AC or DC calibration? If AC at the switching frequency or some other frequency?

Play fair. State clearly what you are trying to do and what you have done to accomplish the goal.

?-)

To keep things simple, I am calling it resistive due to the aforementioned LOW geomagnetic frequencies involved (not DC) and air core.

Depending on the load characterisitics of the LED driver, there may also be a series resistor involved which would be far higher in value than the coil itself.

If inductance was an over-riding issue, I would have said so.

The question is simple. Can I attach a coil to the output of the LED driver instead of LED's?

If so, does the coil need to be combined with other components to protect the driver?

If no one has a working knowledge of this type of device, O don't see much point in going into further detail.

Robert Leavy