12v->5v inverter sounds odd?

Technical Electrical
#1

Our power inverter for the d-link emits this quiet, high-pitched, dog-whistle-type noise each time we try to power it from it’s own special 12v connector on the end of the PD board. When we plug it into a normal, 20-amp line, however, it’s *totally *silent. But, because we’re powering it from the normal PD board slots, it reboots every time we pull too much from the battery, causing us to lose comms and sanity. :rolleyes:

Any ideas on how to fix this? Should we try a different inverter? We’re using a brand new PD board and new inverter, but we need to get this fixed because we don’t want our radio rebooting every time we start a match.

#2

I wouldn’t worry too much about it, some power circuits do put out a little bit of noise. Though just curious, are you sure it is the inverter that is making the noise and not the 12volt power supply on the PDB? That I have notices to be a bit noisy in a very quiet room.

#3

Ear plugs.
No, seriously. The noise is switching whine, and no cause for alarm. That is, it doesn’t mean there is a component in danger of failing.

#4

I wish I could hear it.

Too many loud rock concerts in the 60’s.

#5

It’s nothing to worry about. It is a buck converter so what happens is that there is a transformer that is toggled on-and-off by a MOSFET, controlled by some very high-speed response chipset. That way, it can convert that high voltage to a lower voltage, higher amperage, with a theoretical 100% efficiency (though most are between 80-90%).

That sound is because when the MOSFET is toggled, the magnetic flux caues the transformer to resonate to nearby steel things/motors/magnets/earth’s magnetic field.

So again, don’t worry about it. Only worry about it if it is making a kinda low-pitched screaming sound, meaning that there’s heavy load or it is shorted out. If you are getting that mean and groaning noise, pull out a multimeter and measure the amperage. If it is close to 5 amps, you’ve got yourself a problem!

Good luck and don’t get scared by high-pitched sounds coming from these devices.

#6

Thanks guys!

#7

Invictus,
The sound should become less noticeable when you connect the radio. Without a load, the circuitry is hunting for a good operating point. When it does that, anything that is not tight in that circuit (transformer windings, magnetic cores, even flexible wire) will emit energy in the audio spectrum. This is a good reason to tell people to not mount the regulator near or on the radio. There is a lot of RF hash emitted by that little box that can affect the wireless link.