---
# System prepended metadata

title: Regular Meeting (2022.12.12)
tags: [Regular Meeting, DeWei]

---

# Regular Meeting (2022.12.12)

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

## FW of CDCFE-Prototype

![](https://i.imgur.com/v1CFQwz.png)

* 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`