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+====== GCA-PI06 5V 3A Power Supply ======
+[[english|{{  rocrail-logo-35.png}}]][[:rocnet:rocnetnode-en|{{ :rocnet:rocnet-hw.png}}]]
+[[english|Content]] -> [[hardware-en|Hardware]] -> [[hardware-en#rocnet_with_raspberry_pi|GCA-RasPi]]
+  * [[GCA1-PI01-en|GCA-PI01]] | [[:rocnet:pi01can-en|Pi01CAN]] | [[GCA_PI02-en|GCA-PI02]] | [[GCA-PI03-en|GCA-PI03]] | [[:gca-pi04-en|GCA-PI04]] | [[:gca-pi05-en|GCA-Pi05]] | **[[:gca-pi06-en|GCA-Pi06]]** | [[:GCA-PI07-en|GCA-PI07]] | [[:GCA-PI08-en|GCA-PI08]] | [[:gca107-en|GCA107 Relay board]] | [[:rocnet:rocdisplay-en|RocDisplay]] | [[:rocnet:fastclock-en|Fast Clock]]
+  * [[mgv-overview-en|The GCA modules]]
+  * [[:rocnet:rocnetnode-en|RocNetNode]]
+ \\
+^^^^By Peter Giling ^^^^
+[[http://raspberrypi.org|“Raspberry Pi" is a trademark of the Raspberry Pi Foundation.]]\\
+ \\
+===== The reality =====
+|  {{:gca:gca_pi06_pict_02.jpg?400}}  |
+|  The final result, easy to build, easy to connect  |
+ \\
+ \\
+=====Power supply difficulties=====
+The choice of using 5V adapters for supply of RocNet was obvious.\\
+There is a massive assortiment of 5V adapters to choose from, and also for good prices.\\
+But depending on the load drawn from the 5V adapter the following problems could occur:
+  * The Raspberry Pi shuts down or reset by itself.
+  * The Ethernet connection is signaled OK by the Raspberry LEDs but does no longer operate correctly.
+  * No SSH session is possible or an existing is stalled.
+  * RocNetNode does not respond in the LAN.
+  * The middle position of the Pi04 acts the same as  the left position.\\
+It proves that all these negative aspects are referring back to the too-low voltage output from the adapter itself.\\
+The indicated voltage of 5V is not very seldom as low as 4,2 or 4.3 volt.\\
+Adding that to the small but normally acceptable loss in the RJ12 cables, could lead to the effects as indicated above.\\
+**So we need a better supply**.\\
+ \\
+=====Description of how to achieve that=====
+The GCA_Pi06 has been developed to provide a real stable 5V 3A power to a RocNetNode setup.\\
+It contains a switching power regulator with solid output of 5V.\\
+It only needs a 8-20 Vac or 12-24 Vdc input line, minimum 16 VA, for the full load of 3 Amp. \\
+Amp might be overdone, but most regulators otherwise are made for 1 Amp, which will be too close to what we at least need.\\
+GCA_PI06 makes a home power line unnecessary under the model railroad layout. \\
+Linear regulators are not suitable in this case.\\
+The Raspberry alone already consumes 600-700 mA at 5V.\\
+A standard 16V transformer will give you easy up to 22V after rectifying.\\
+This means that a linear regulator like LM7805 has to radiate approx (22-5) V x 0,7 Amp is approx 12 Watt into heat!\\
+Even with a massive cooling part it will be pretty hard for this very well known regulator.\\
+This board will be at minimum efficiency with max load and then it is still 77%.\\
+With the same 22V and normal 1-1,5A load the efficiency is approx 85% so the board will have to radiate approx 1,2 W.\\
+In this case we do not need any additional cooling,\\
+The pc-board has as much surface as possible dedicated for that.\\
+The Pi01, Pi02, Pi03 and Pi04 are connected directly to this board by a RJ12/45 cable in which the I2C lines are passed to all connectors.\\
+According to drawing below, also chaining from one PI02 or PI03 to the next is optional.\\
+:!: Prevent making loops.\\
+===== Power for Raspberry Pi 3. =====
+With the introduction of Rasberry Pi 3, there is new situation.\\
+PI 3(as we call for short) is consuming much more power.\\
+With powering all boards via GCA_PI06 supply, there will be a problem when cable(s) between\\
+PI 3 and GCA_PI06 are too long (> 0,5 m).\\
+The used RJ12 cables can not handle that current.\\
+So two possibilities are to be mentioned to overcome this minor problem.\\
+  *  1  Shorten connection between PI 3 and GCA_PI06 to less than 0,5 m.\\
+  *  2  Use RJ45 Ethernet cables and connectors between GCA-PI06 and  PI 3\\
+Fortunately, the boards are designed to install either RJ12 or RJ45 connectors.\\
+RJ45 will make wiring more solid, and also, more than one wire is used for power supply.\\
+In kits, available from GCA, there can be a choice between RJ12 or RJ45 connectors.\\
+ \\
+=====Connection example=====
+{{:gca:gca_raspi_overview_1.png}}\\
+  * The Raspberry Pi gets its power through the GCA-Pi01; No additional power adapter needed.
+ \\
+===== Need more Power? =====
+It is possible that even his power supply does not match your needs.\\
+So the idea comes near to use more than one GCA-06 units in the RocNet network.\\
+Basically no problem but please use separate adapter/transformer for supply of GCA_PI06.\\
+Using the same adapter/transformer for multi GCA_PI06 units can cause many unexpected problems.\\
+It is strongly discouraged. \\
+===== Hardware =====
+|{{:gca:gca_pi06_sch.pdf|The schematics  }}  |
+|{{:gca:gca_pi06_pcb.pdf|The PCB with parts positions}}  |
+|{{:gca:gca_pi06_parts.pdf|Bill of materials}}  |
+|{{:gca:gca_pi06_gerber.zip|The Gerber files}}  |
+^ N.B. Only complete ordered kits will be supported! ^