Hello Friends,

This picture is from internet, what's marked with green dots are part of a boost converter circuit, it boosts to 5v, the other components are sot 23 with A19T marking ( seems to be a P Mos ), the other sot 23 I don't know what marking says, is not visible due to hot glue and the refraction makes the digits blurry. However, the A19T drain is connected to the inductor, and looking at the schematic of the Boost converter with PH0I (TI) marking capacitor, EN pin, SW pin and Inductor are connected to Vin, the resistor behind A19T seems to be connected the the source pin and the drain of the other sot 23, there is a via to the side of that resistor but it doesn't seem to be connected to the source of A19T.

I'm a newbie, by chance do u know what's the other sot 23 and what they do to the boost circuit? ( at first I tho only the A19T was part of the boost circuit, and the porpuse was to enable or disable the the boost converter )

Increase the screen brigthness.



Hope your answers, thanks!

 

This is a generic boost coverter:
So if the inductor connects to the drain of the MOSFET, then it is most likely an N-channel MOSFET.
Is the other device a TL431 or something else involved in the regulation of the output?
Where does the MOSFET get its gate drive signal from?

 

This is a generic boost coverter:
View attachment 351923So if the inductor connects to the drain of the MOSFET, then it is most likely an N-channel MOSFET.
Is the other device a TL431 or something else involved in the regulation of the output?
Where does the MOSFET get its gate drive signal from?

Hi Ian0,

I think the gate is drived by a MCU, but not sure if both gates in case the other device it is a mosfet too.

According to the marking the A19T it is the AO3401A whose datasheet states it is a P mos, I don't know what's the other component can't see throught the hot glue, I don't have the board it is a picture from internet, about the PH0I boost converter look a the diagram found on datasheet, it doesn't even have a mosfet, model name TPS61040DBVR:


I have doubts like the converter already has its own switching device inside, what could be the porpuse of such mosfet + the other device.

 

PH0 could be Torex XC6368E601MR.

 

PH0 could be Torex XC6368E601MR.

Hi MrChips,

In the XC6368E601MR the mosfet is placed between L1 and D1, and in the board before L1, can the mosfet be conected either way of the L1?

 

Hi MrChips,

In the XC6368E601MR the mosfet is placed between L1 and D1, and in the board before L1, can the mosfet be conected either way of the L1?

Same circuit as I posted (but with external instead of internal MOSFET):