Output voltage problem with StepUp Booster 3.3V

[warmaniac]

Hi ,

I ordered 5 pcs step up boosters from different sellers on ebay.com

like here http://www.ebay.com/itm/222350595744?_trksid=p2057872.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT

and the problem is my output voltage which is from 3,75 - 3,83 Volts, tried many types of new batteries 2xAA input voltage was about 3,10 - 3,20 Volts . How can I solve it to have stable about 3.3 Volts .

Thanks much.

[boozz]

@warmaniac
Have you measured this while 'under load' or free running? You could also add a electrolytic condensator (100 uF or so) in order to make sure that you're flattening the ripple.

BR,

Boozz

[warmaniac]

I measured it on VCC of radio , radio isn't working, alredy tried to add 100 uF capacitor after booster V out , but it not working.

[pansen]

what is written on the chip? looking at the datasheet there's versions ranging between 3.0 up to 6.0V in 0.1V steps:

[boozz]

@warmaniac

Are you sure you're not measuring the ripple. These modules are not really known as 'quiet' in terms of stable output voltage, hence the question of the elco.

Have you tried them 'stand-alone' (no radio) and with a decent load (e.g. a resistor drawing a few milliamps or so).

BR,

Boozz

[pansen]

true, they actually need some minimum load to function properly but the datasheet does not mention anything about it..

[warmaniac]

If I understand correctly, It was measured under load , arduino mini pro 3.3V with nrf24l01+ as door sensor.

@pansen
on the chip is written
LA 3.3
17B3S

[warmaniac]

@pansen

PIN Configuration :

SOT-89-3

[boozz]

@warmaniac

You mean both the pro-mini and nrf24l01+ are fed via this module? In that case you could say that there should be enough load for the power module to get into the 3.3V modus...

[warmaniac]

yep , it works well without step up booster , but when I added it, voltage is too high for radio :(

[boozz]

@warmaniac

Strange...

Have you considered using a zener (3.3V) as a protection device next to the step-up booster module?

BR,

Boozz

[warmaniac]

@boozz

Could you please send me what you mean ?
Something like this ?
http://www.ebay.com/itm/New-Zener-Diode-DIP-1-2W-0-5W-2-4V-8-2V-14-Values-Choice-Free-P-P-/262770408086?var=&hash=item3d2e563a96:m:mHD19Qu_1sjnfaWnrsCUbPQ

Will not be generating additional energy consumption?

[boozz]

@warmaniac

The zener crossed my mind as a simple but effective way to create a stable 3.3V. It might cost some 'bleeding' amps, maybe you could limit it by using a proper series resistor.

See this article for some more details.

BR,

Boozz

[emre299]

@warmaniac
hello, i am having the same problem. If there is no booster, the mysensors works(full 2xAA), but if there is a booster, it doesn't connect to the network.
I connected a capacitor to the bosteer input or output and I used 2 different booster and 2 different nrf but it didn't work.

Did you find a way to run mysesors with booster?

[canique]

@emre299 must be something wrong with the booster. Canique Boost module (I run the site selling it) outputs 3.3V no matter if no load is attached or if 50mA or more are drawn from it. It's based on the MCP16251 chip.
I guess the ebay modules are based on chinese chips having minimum price as the one and only design goal. Years ago I've bought 2 different ebay modules myself to test them, but they were crap (unnecessary LEDs and even if they were unsoldered the modules had bad efficiency).

[emre299]

I bought 5 new ones, they didn't work either. I don't understand why it doesn't work Nrf24l01

[Yveaux]

@emre299 the booster likely adds noise to the power line, and it is a known fact that the nrf24 is very sensitive to this.
Either filter the noise, or better, get a decent booster.

[skywatch]

@emre299 @Yveaux Is right. You could try adding a 47uF or 100uF capacitor across the 3.3V and gnd on the radio module. it is known to help in some cases.

If you have access to an oscilliscope you might be able to see the noise. If it is sharp spikes then a 100nF capacitor can help as before. You may need both in parallel on the radio power connections.

[yetifor]

I would like to step up 3.3V from my power supply with the help of a dc-dc-boost converter to 5V and then I want to draw 500mA by placing a 10 Ohm resistor between the output-pin of the boost-converter and ground.