Mikrokopter Megaquad power distribution board
My megaquad power distribution board for my heavy lift quad. I'll try to document what it is and how to put this board together. This is a work in progress and may not get updated when I start loosing interest so bear with me.
1. Power Distribution to the 1hoch4 brushless controllers via a 4 layer board. The board is a 2oz copper and I tried to make it as thick as possible.
2. On board 12V regulation
3. On board 5V regulation
4. On board current sensor
5. i2c buffer chip for isolation and hotswap capability if needed. mainly to protect the brushless controllers from getting fried in a quad setup.
6. molex connector for flight controller support **** special NOTE.. this one is different from Mikrokopter, read below
7. on board LED control compatible with Mikrokopter header (controls 2 sets of LED)
SPECIAL NOTES PLEASE READ!!!!!!!!!
0. The only mandatory thing you actually have to solder on this board, is the tantalum caps for the 5v regulator, the 5v regulator, the 5pos flight control header, the 4 ic's and all the resistors that go with it, and the 330uF cap for the 5v regulator. Optional is the 2 LED transistors, the current sensor, and the 3 pos header for the sensor.
1. Because the board is thick, it sinks a LOT of current but also a lot of thermos. It takes a lot of heat to remove anything you mounted on the ground or power planes. What this means for you is that if you mount those capacitors it will be very hard to remove unless you have an 80watt soldering iron and some flux. So please solder with care and make sure you got the right polarity.
2. A note on the capacitors. Please mount the capacitors on the ESC side and not on the board side like they do with Mikrokopters. You run the risk of blowing out your ESC's if you do it on the board side. For 1hoch4 I am using low impendance capacitors of about 680uF from newark.com. I think with the bigger motors you need more then 330uF.
3. There was a problem in production where I forgot to tell them to slot the holes for the current sensor. Because of this you can't push the current sensor through the hole. Instead just take a big dyke and cut it a little shorter then surface mount it on the board. Works just fine. Do not drill into the board. Although you could do it, it will be hard to solder to the inner layers.
4. For the 1hoch4, I originally ran 5v from the ESC to the Enable pins labeled EN1 for enable on motor 1 on the power board. The problem with this is when the ESC's are under heavy load they don't output 5v and it drops a little. This can cause a problem with the isolator chips thinking the ESC's went offline. To remedy this on this version of the board all we can do is hard wire the EN pins to 5v (5v from the 5v header). Upon further investiation this problem may strictly be due to the 2 capacitors I had. On my hexa I currently take 5v from pin 2 on the BL 2.0. For the 1hoch4 I still use an external 5v supply. Seems as tho the 1hoch4 5v regulator can't really supply much more power to external peripherals.
5. I've provided 2 locations for the i2c bus. You will notice that C and D are available on all left arm location and is compatible with the mikrokopter brushless layout. C is always on farther out side toward the edge and D is always closer to the center. I've created a jumper area so enable these locations. So if you use a Mikrokopter Brushless you'll have to solder a bead of solder to create the connection. Just take a look and it'll be pretty obvious what I'm talking about.
If your NOT using the a Mikrokopter controller and you are using a 1hoch4 then you may use the M1C, M1D, EN1 pins for the C/D/5V for i2c. No jumpers needed. Please hook up the 5v to the 5v header (JP3) for ver 2.0.1 of the board. It was a bug that went into production. This will be true from E1,E2,E3,and E4.
6. LEAVE C24 off. Don't solder it. That was a bug and its currenty bweteen pin 1 and 3 when it sould be pin 1 and 2. We don't need this, its on the EPI-STROM board.
7. JUST found out that the molex pin out is inverted. So pin 1 on mine is pin 5 on the mikrokopter distro board. You will have to make a cable harness and have it roll over. I don't have a 2.1 flight controller so please just meter it out and double check everything. ie
pin 1 -> pin5
pin 2 -> pin4
pin 3 -> pin3
pin 4 -> pin2
pin 5 -> pin1
8. Pin 1 on the IC's are on the top left corner. Pin 4 is ground if that helps any. So if the ic is labeled U$1 for example, then pin 1 is right below the U. Tht is also the side of the chip where there is a slant indicating pin 1 side.
9. Do not solder the onboard LEDS for the chips. You only have to deal with soldering LED1 and LED2, and even those are optional. LED1 and LED2 are status LEDs for the regulators.
Mounting holes - 64mm on center 3.2mm for flight controller stack
83.4mm on center 4.2mm for mounting to chassis
One thing you will want is the parts list and possibly a diagram. So here you go
Refer to the schematic if you have questions.
When soldering notice that positive for the big tantalum caps are facing towards motor 1. When soldering the LED's, just hold it in place to see if it turns on to find the polarity. You would be wise to buy some quickchip flux, sharp soldering tip, a tweezer, and just in case you make a mistake some soldering braid to desolder parts.
All rights are reserved by me.. Feel free to throw some money my way if you want to reproduce anything