Pogo pins power clarification - reading schematics
Hey,
yes this is a long response...
I guess some people who where not formerly involved, would have some difficulties to get it, i guess (no offense, but good thoughts from all of you!!).
So to make it shorter from my side, and hopefully to shed some light on all this again, i just thought it may help to have all parts involved on one sheet.
Maybe a picture says more than 1000 words.
Hopefully i did not miss anything... so the following is just my best guess again, not trying to go into to much details.
In fact we should try to draw things down a little:
- D600 discussion: this component is just a standard part to make the boost converter based on LP6226 work.
It is essential for the functionality and to reduce loss it should be a schottky type.
- PMIC in general and the logic inside: Don't forget that there's some kind of a default state machine inside the PMIC to handle evident parts even when coming out of reset.
The MOSFETs between DCIN and PS inside AXP803 play a decent role as well...
The other part is all the driver stuff and registers to be set by software later on.
In other words, you need some useful routines to make it work as it was designed and to not burn things up.
- Pogo-Pin Power Supply Input: AFAIK DCIN should be used, but you'll need to add a schottky diode to protect the power supplies from working against each other.
The trick would be, to not go higher as 5V with the input voltage at the anode.
In case a USB Type C charger gets connected the diode would prevent the a current flow form the phone into the breakout.
If you further take the assumption that USB type C charger delivers 5V, the following would match...
On the other side, a 5V supply on the breakout board would not be sufficient to overcome forward voltage of the diode to drive against USB Type C charger.
- LPW5206: Just does what it should from my point of view...
If the PinePhone role switches to host it puts the output voltage of the boost converter to the Type C connector.
The MOSFETS inside PMIC should not be active then and prevent a flow back in the circuit. This is what the PMIC driver should handle.
- I must admit, that i think as well there are some design flaws inside this phone.
That's it by now... TBC
Cheers,
scholbert
yes this is a long response...
I guess some people who where not formerly involved, would have some difficulties to get it, i guess (no offense, but good thoughts from all of you!!).
So to make it shorter from my side, and hopefully to shed some light on all this again, i just thought it may help to have all parts involved on one sheet.
Maybe a picture says more than 1000 words.
Hopefully i did not miss anything... so the following is just my best guess again, not trying to go into to much details.
In fact we should try to draw things down a little:
- D600 discussion: this component is just a standard part to make the boost converter based on LP6226 work.
It is essential for the functionality and to reduce loss it should be a schottky type.
- PMIC in general and the logic inside: Don't forget that there's some kind of a default state machine inside the PMIC to handle evident parts even when coming out of reset.
The MOSFETs between DCIN and PS inside AXP803 play a decent role as well...
The other part is all the driver stuff and registers to be set by software later on.
In other words, you need some useful routines to make it work as it was designed and to not burn things up.
- Pogo-Pin Power Supply Input: AFAIK DCIN should be used, but you'll need to add a schottky diode to protect the power supplies from working against each other.
The trick would be, to not go higher as 5V with the input voltage at the anode.
In case a USB Type C charger gets connected the diode would prevent the a current flow form the phone into the breakout.
If you further take the assumption that USB type C charger delivers 5V, the following would match...
On the other side, a 5V supply on the breakout board would not be sufficient to overcome forward voltage of the diode to drive against USB Type C charger.
- LPW5206: Just does what it should from my point of view...
If the PinePhone role switches to host it puts the output voltage of the boost converter to the Type C connector.
The MOSFETS inside PMIC should not be active then and prevent a flow back in the circuit. This is what the PMIC driver should handle.
- I must admit, that i think as well there are some design flaws inside this phone.
That's it by now... TBC
Cheers,
scholbert
