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Topic: Switch on/off MP3 player by using transistor (Read 1 time) previous topic - next topic

jose_francisco

OK.

The player needs 270mA and uses a 3.7v battery. I will check the minimum voltage needed.

It will be operated by a 3v3 "timer". This "timer" needs to be powered with, at least, 4.5V. And it uses a internal LDO regulator. It needs about 8mA.

The whole thing needs to be energy efficient. That is the reason I use the step-up regulator only to feed the "timer". I can use the step-up to provide 4.5 volts to the transistor but the system will be less efficient.

Thanks.

Wawa

That diagram powers the Mp3 player with less than 2.6volt.

How are you controlling it.
I don't see any control/data lines.
The data lines will also power the device.
Leo..

jose_francisco

The module will start automatically once powered by the battery (tested and working)
How can I increment the supplied voltage?
Thanks

Wawa

Switching supply or ground and ignoring control lines might not fully power down the device.
It might even damage it.

If you insist on not exploring the sleep mode of the device, then use diagram#3 on this page.
Leo..


jose_francisco

#19
Jun 19, 2018, 02:02 pm Last Edit: Jun 19, 2018, 02:14 pm by jose_francisco
This one Wawa?

Thanks

As a reminder: I need to switch 250mA@3.7v (4.2-3.5v) using a 3v3 signal.

Wawa

#20
Jun 19, 2018, 11:13 pm Last Edit: Jun 20, 2018, 08:42 am by Wawa
Yes.
Could replace the logic level p-channel mosfet for a PNP transistor if you don't have one.
At a cost of some switch voltdrop.
Q1 collector circuit needs to be changed for that.
Leo..

jose_francisco

Thanks.
How much voltage drop will I have?
I will order those references. Any advice about better ones?
Thanks again.

Wawa

Minimal if you use the right fet. The FDN340P seems to be suitable.
Don't expect to find a small logic level P-channel fet in a through-hole package.

Remember I warned you for the signal lines.
Leo..

jose_francisco

Ok

I'm ordering 2n3904 and FDN340P.
R1=660 ohm
R2=1 kohm

Will the MP3 module be activated on uC High or Low signal?

Thanks again.

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