Flatpack2 Control

One of the purposes of use of the Flatpack2 rectifiers family in HAM radio is a power source for MOSFET-based Power Amps, where voltage source of 48-53V (combined with from 5 to 20A) is needed. One of the PA examples are the production line of EB-104.

Disclaimer: Please note tha use of EB-104 products should be with care and assumes user understands and follow local country licenses and regulations. (However, licensing and regulations are out of scope of this article).

Here are some Flatpack2 pro and contra, found by myself as the user of product, combined with EB104-based PA for more than 8 years:

- Robust design. Mmy FP2 HE2000 survived IOTA DXpeditions and that is saying something :)
- Low EMI. It definitely is. However common care should be taken. As per my experience, it is better to keep FP2 in separate power supply box. Setting up FP2 in same box with PA may require extra EMI protection needed. I personally found it easier to keep rectifier in seprate box.
- Fair enough size/weight combined with value for money.
- CAN bus capability
- Limited variation of output voltage. Generally, most of Flatpack2 models can vary between 48V-54V output
- Extra work needed to connect Flatpack2.

However, taking considerations is all above (and assuming there are alternatives on rectifiers market), the FP2 capability of CAN bus comminication is very useful for SDR-based projects and own programms/controls and applications.

There are many sources of the Flatpack CAN protocol (Example). And there are a lot of examples of Arduino and ESP32 CAN communication basics (Example, Example).

There are few designs of the PCB, which can be found at Ebay and AliExpress. And, surely, you can create your own, matching your applications. One of the considerations found while making PCB design to my own application was the size and PCB capacity, handling required power rating. Brief calculation gives the following theoretical results regarding using 1oz or 2oz layer copper for PCB:
- 1oz PCB can handle max 15A with temperature variation of +25+30°C on full continuous load
- 1oz PCB with max load up to 25A, temperature +50°C
- 2oz PCB with max load up to 30A, temperature +25°C
- 2oz PCB with max load up to 40A, temperature +40°C

Application rationale:
Originally I was used PCB purchased from Ebay few year ago, made by "xygax". I belive this was the one.Generally speaking there were only few considerations regarding PCB sizes (including kind of overkill length of active AC contacts), otherwise it was good. However, with new PA and moving to unified control for SDR, PA and ATU I was desided to make custom design for the rectifier PCB and connect it to ATUcoltrol with MQTT.

In addition to the PBC connector board, there is PCB which suits either ESP32D or ESP32U and very common CAN bus module CJMCU-1051 TJA1051.

Gerber files:
Connector PCB
Control PCB

Please note, that the above files may not be the latest design, specifically for Control board. If you need latest one, please contact me. There are no any restrictions of reusing those files for you own purposes.

There are two different and actual designs of the final application:
1. Control with MQTT. This version is more for use in SDR world and it works with ATUconnect.
2. Web-based Control. This version does not support MQTT, however it has the flexibility of web-based confiruration. Here is the example of ready Web-based Control application. User manual can be found here.. This application version is recommended for users outside SDR world.

Both versions are ESP32-based and loaded with closed-source software. If you would like to join the SW development team and get access to the SW sources, please contact me. The distribution of the SW loaded on ESP32 is free of charge and does not require any SW subscribtion or registration.

If you would like to get PCB or ready project, please contact me. I recommend you to explain briefly you application (very brief details please, mostly current limits you are after), this will streamline the proccess. Please note that there is the cost associated with PCB production, SW development and postage. Indicative cost is approximately 9-10AUD for the set of two PCB. Assembled application may certainly cost more and final value is dependent on additioanl factors, which can be discussed per case.

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