A 12V Brushless Fan Motor Driver

357

03:51:53

some fan circuit I pulled out of a computer fan.  Linear Hall effect sensor is a 3pin U18 something, looks like open collector output.   represented in the simulation by the clock and Q1. coil is bifilar wound and connected directly to +12V in opposing polarity.  Q2/Q3 are some TO92 that I can't read.  Q2 is biased on and gets pulled low by the HE.  Q3 is driven from the output of Q2 directly.  diode just looks like reverse polarity protection?  simulation without the diode shows the coils want to pull current back up through the base junctions, so it's probably protecting against back EMF as well.

published 11 years ago

Sine_eyed

11 years ago

Nice bit of reverse-engineering -- those built in PCBs can be damn small. Simulated operation looks very nice- well done..

faceblast

11 years ago

updated it with more realistic speeds

spammailbox

11 years ago

Damn impressive. One of the nicest simulation uploaded. Wow...

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.