Using Inductive Charging as voltage converter

For Adafruit customers who seek help with microcontrollers

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
rahatmaini
 
Posts: 176
Joined: Wed Aug 29, 2012 5:15 pm

Using Inductive Charging as voltage converter

Post by rahatmaini »

I realized that since the Inductive charger in the store pretty much converts a high voltage to 5V to be received by the other coil, why not just use THAT instead of the DC voltage converters you sell in store, it seems easier (I don't even know how to use the Mini DC/DC Step-Down (Buck) Converter, it would be nice if you could put up a diagram on that) plus its wireless charging!! What benefits does the Mini have (except being small) or the UBEC one have?

Thanks! Also, can someone tell me how many Amps at 5V are needed to supply power to a Raspberry Pi?

User avatar
adafruit_support_mike
 
Posts: 67454
Joined: Thu Feb 11, 2010 2:51 pm

Re: Using Inductive Charging as voltage converter

Post by adafruit_support_mike »

You've bascially described a transformer, which is indeed a highly efficient and popular way to convert one voltage/current level to another.

The main difference is that transformers work best with AC signals while switching regulators work best with DC signals. The device that's best for any given application depends on the input and output you want. There are inevitable losses when you convert AC to DC and vice versa.

If you have a DC input (from a battery, for instance), you can lose a fair chunk of power creating an AC waveform, converting the voltage/current levels through a transformer, then rectifying the new AC signal back to DC. A switching converter may end up using the power more efficiently.

It's especially easy to make a highly efficient DC step-down converter. That uses techniques from IC design called 'switched capacitors' which simulate resistors without the large 'losing energy as heat' problems you get from a resistor per se.


WRT the RasPi, the official peak current is 750mA, but it drops to the 300-400 range when the CPU is idle. You want a 5v @ 1A power supply for one. Make sure the output is very clean though.. spikes in the power can make the F3 polyfuse fail faster than its expected lifespan.

Locked
Please be positive and constructive with your questions and comments.

Return to “Microcontrollers”