[chbot] Really good step-down converter...

[Volker Kuhlmann]

So I bought this step-down converter module from an Asian company (not
alixpress). The main culprit is a Monolithic Power MP1584. Let's see
about its performance...

Input voltage: 11V
Input current: 216mA
Output voltage: 4.97V
Output current: (over 10ohm) 497mA
Efficiency: 104% wooot!!

I can do bulk orders for all you guys because I'm nice...

Time to distrust the Tenma benchtop display and to check all the croc
clips.

This looks better:
	U in	I in	P in	U out	I out	P out	eff
	 8.98V	0.22mA	1.98mW	5	0	0	---
	11.98V	0.23mA	2.76mW	5	0	0	---
 	 8.98V	6.2mA*	55.7mW	4.975V	8.86mA	44.0mW	79.1%
	11.89V	5.24mA*	62.3mW	4.976V	8.84mA	44.0mW	70.6%
	 8.99V	 24mA	216mW	4.97V	40.1mA	199mW	92.4%
	11.94V	 17mA	203mW	4.97V	40.1mA	199mW	98.2%
	 8.4V	278mA	2.335W	4.974V	425mA	2.114W	90.5%
	11.6V	204mA	2.366W	4.97V	426mA	2.117W	89.5%
Starting up with load connected and input current limited causes the circuit
to lock up at the input current limit with the output under voltage.
So if the power-on current can't be met the circuit fails to start.
Input and output current fluctuate noticably, but output voltage does not. Not
sure what measurement effects are at play here.
Tiny trimmer difficult to adjust.
Gets warm at 0.5A, I wouldn't trust the 3A promise.

http://www.hotmcu.com/mp1584-buck-step-down-3a-adjustable-regulator-module-p-82.html
Inductor 6.8uH (unlike pictured).

Volker

-- 
Volker Kuhlmann
http://volker.top.geek.nz/	Please do not CC list postings to me.