# Regular Meeting (2022.12.12)

* FW of CDCFE-Prototype
* 48-channels fanout board- regulator
* Reverse engineering about Altera USB blaster

## FW of CDCFE-Prototype


* Bus error
* The same to prevuous I did
* Asking Yu??

## 48-channels fanout board- regulator

* Previous we use [+5V LDO MCP1727](https://hackmd.io/M-v_rjZKSKGRH43tHGPLxA#2-Board) is not better than 7805 about noise, see [here](https://electronics.stackexchange.com/a/529110/243146), but has other advantages worth us applied it!
* But MCP1727 has a good advantage
* Start delay(soft-start) to prevent [inrush current](https://hackmd.io/@pd-driver-ntuhep/SkceKkJ_i)
* 1.5A output
* Low Drop: 300mV max
* 7850 has drop >1V, even 2V on the high load
* Soft start
* Not high cost ~30NTD/1pcs
* Little noise(ripple) rejection
* Suitable for first stage LDO
* Second stage LDO: [TPS7A20](https://www.mouser.tw/ProductDetail/Texas-Instruments/TPS7A2050PDBVR?qs=hd1VzrDQEGgpoyZ%2F5FZYnQ%3D%3D)
* 300mA output
* Good [PSRR](https://en.wikipedia.org/wiki/Power_supply_rejection_ratio)
* Low cost: ~20NTD/PCS
* Small size
* Not sured:
* 1 stage 5V-LDO: Output 5V but has 300mV max drop
* 2 stage 5V:
* V2i < 5V (4.9, 4.8, 4.7)---> Does 2 stage still working fine?
* Must buy it go to here, and add load testing
* If can't working fine, solutions:
* 5V (1 stage LDO) -> 4.5V (2 stage LDO) -> Load
* 5V is so convenience, powerbank, usb...etc. applied 5V
* Reduced dynamic range (4.5V)
* 6V (1 stage LDO) -> 5V (2 stage LDO) -> Load
* 6V is not very common voltage

## Reverse engineering about Altera USB blaster

* Few infomations about usb blaster ii
* [3rd made](https://blog.csdn.net/lichenllin/article/details/94903178)

###### tags: `Regular Meeting` `DeWei`