Lenovo ideapad 5 windows 11 update disable charging circuit?

[bogart219]

Going back to this post on page 4, it's the AE version from your latest pictures; now which one was the original?




It says
TPS65994
AE
TI 218G2
A9D8 G4

This one "AE" appears to be older, "218" maybe means year 2022, month 2 (february), maybe it's the original one after all?


--------------

The other one "blank line" says "338", maybe 2023 , month 3 (march) (newer)?, since you said you ordered the "AD" version from Digikey, this one is the AD...



Here's the link for the AE version, hopefully you can change your order
https://www.digikey.com/en/products/...erslr/14634219

Your right,I wrote down what I believe was the original TPS chip but didn't include the "AE " in the second line for some reason. I didn't order yet, so I will order now the one " AE version "you linked to. thanks!

[bogart219]

Ordered yesterday.

[bogart219]

Hello again my friend. I soldered on those two new mosfets and that new TPS chip and I'm back to my flashing usb meter. When I test voltages when I can find any, the multimeter flashes.
What is weird, one time I found a solid 20 volts to ground on pin 4 of the usb-c charging port. When I went back to check again 5 minutes later, the 20 volts was gone and the meter was flashing 1.9 volts. Go figure.



Here are the mosfets and TPS chip I put on. I know it looks like shit but I believe their making the right contact. I don't know what to do at this point,so disappointed

[m1ch43lzm]

PQ8302 looks a bit crooked, looks like it's shorting S-G
I also saw what looks like a wire (maybe a strand of solder wick) near a cap, and a solder blob
If that doesn't fix it i don't know what to do anymore
Always measure resistances before applying power
Measure again the resistances on the 4 MOSFETs S-D, S-G, D-G

[bogart219]

Hello. wouldn't you think that if something was shorting out, it would heat up? My thermal camera doesn't show anything. i' going to check what you suggested, then remove components one by one till I get that flashing to stop. BTw, I think that new TPS chip I ordered and put on is the same as the old one i ordered, It has AE on the second line.

[m1ch43lzm]

Hello. wouldn't you think that if something was shorting out, it would heat up? My thermal camera doesn't show anything. i' going to check what you suggested, then remove components one by one till I get that flashing to stop.

Not always, a short circuit from a power rail to GND may cause 2 things:
1. Trigger a protection, internal or external (as in, not turning on a MOSFET), in that case nothing will get hot
2. Something gets hot, if there's no short circuit protection on that rail

But if you short a signal line to GND, or a signal to other signal pin, nothing will get hot

BTw, I think that new TPS chip I ordered and put on is the same as the old one i ordered, It has AE on the second line.

Please review your past order details at Digikey
The AE should be the correct one for Alder Lake platform (12th gen Intel CPU, the one you have) according to schematics from other brands (Dell, Asus) and this forum post from TI
https://e2e.ti.com/support/interface...t4-host-design

Our device recommended for Intel Alder Lake is TPS64994AE and later. TPS65994AD will support upto Intel Tiget Lake. Both are USB4/TBT4 capable.

AD is for Tiger Lake platform (11th gen Intel CPU)

[bogart219]

Not always, a short circuit from a power rail to GND may cause 2 things:
1. Trigger a protection, internal or external (as in, not turning on a MOSFET), in that case nothing will get hot
2. Something gets hot, if there's no short circuit protection on that rail

But if you short a signal line to GND, or a signal to other signal pin, nothing will get hot


Please review your past order details at Digikey
The AE should be the correct one for Alder Lake platform (12th gen Intel CPU, the one you have) according to schematics from other brands (Dell, Asus) and this forum post from TI
https://e2e.ti.com/support/interface...t4-host-design

AD is for Tiger Lake platform (11th gen Intel CPU)

Thanks for the short lesson Right now the AE version is on the board, so we should be alright. I'm going to remove all the components that I screwed with one at a time till I see that flashing stop. I think your on to something there , I might have two or ore signal pins touching. I'll get back to you! Later

[bogart219]

Howdy. I start back tracking, removing components that I changed or messed with. I removed two mosfets , 02 & 04, one at a time, meter still flashing. Removed the TPS chip, usb-c meter STOPPED FLASHING, showing 5 volts. So something connected to the TPS or the TPS is defective or the wrong one. I'm going to put the mosfets back one at a time to see if that matters. Not sure how to determine if the TPS is bad or not. Pray for me.

[m1ch43lzm]

The TPS should negotiate the 20V when everything is correct, you did have at some point 20V, but something went wrong here
Measure the MOSFETS on resistance mode first before powering on the board (source-drain, source-gate, gate-drain)
Measure the resistance to GND of +5VALW, before and after installing the TPS65994
Measure the resistance to GND of +3VALW, before and after installing the TPS65994

[bogart219]

The TPS should negotiate the 20V when everything is correct, you did have at some point 20V, but something went wrong here
Measure the MOSFETS on resistance mode first before powering on the board (source-drain, source-gate, gate-drain)
Measure the resistance to GND of +5VALW, before and after installing the TPS65994
Measure the resistance to GND of +3VALW, before and after installing the TPS65994

Where exactly should I measure the +5VALW AND THE +3VALw at Mich?

[m1ch43lzm]

+5VALW is at PJ6206, also present at CU201, or at PL6202
+3VALW is at PJ6201, PL6201, also at pin 32 of the TPS65994, labeled VIN_3V3_PD1
Make sure you reconnect the solder jumpers at PJ6201, PJ6206

[bogart219]

+5VALW is at PJ6206, also present at CU201, or at PL6202
+3VALW is at PJ6201, PL6201, also at pin 32 of the TPS65994, labeled VIN_3V3_PD1
Make sure you reconnect the solder jumpers at PJ6201, PJ6206

Thank you Mich!

[bogart219]

+5VALW is at PJ6206, also present at CU201, or at PL6202
+3VALW is at PJ6201, PL6201, also at pin 32 of the TPS65994, labeled VIN_3V3_PD1
Make sure you reconnect the solder jumpers at PJ6201, PJ6206

DID.

Well Mich, we're pretty much back to where we started. The USB meter is is no longer flashing and showing 5 volts again after I put those components back on being more careful. Still the voltages are missing at those locations you pointed out.

5 VOLTS - PJ6206 - 1.3 VOLTS 3 VOLTS - PJ6201, PL6201 & PIN 32 ON THE TPS chip = all 0 volts.
CU201 - 1.3 VOLTS
PL6202 - 1.3 VOLTS
What do you think?

[bogart219]

I'm trying to wrap my head around this PD controller having to "negotiate" with the power adapter. So I got 5 volts to certain places. This schematic is confusing for me to understand. for instance, I'm trying to to follow the the inputs and outputs of the Pd controller chip. As seen in this shot, These pins on the Pd should be 5 volts. They are all 1.3 volts on mine. There are some pins that have 5 volts.


How do you tell the inputs and outputs on this chip? where is the main power rail on this board? Where did that 1.3 volts come from? Thanks

[bogart219]

The TPS should negotiate the 20V when everything is correct, you did have at some point 20V, but something went wrong here
Measure the MOSFETS on resistance mode first before powering on the board (source-drain, source-gate, gate-drain)
Measure the resistance to GND of +5VALW, before and after installing the TPS65994
Measure the resistance to GND of +3VALW, before and after installing the TPS65994

Just to clarify, so when the TPS negotiates the 20 volts, it sends that voltage to the mosfets below it? I'm trying to see which way the current is supposed to flow? when working properly, what should the gate voltage be on those four mosfets? Two are high and two are low correct?

[m1ch43lzm]

I'm trying to wrap my head around this PD controller having to "negotiate" with the power adapter. So I got 5 volts to certain places. This schematic is confusing for me to understand. for instance, I'm trying to to follow the the inputs and outputs of the Pd controller chip. As seen in this shot, These pins on the Pd should be 5 volts. They are all 1.3 volts on mine. There are some pins that have 5 volts.


How do you tell the inputs and outputs on this chip? where is the main power rail on this board? Where did that 1.3 volts come from? Thanks

+5VALW and 3VALW are generated by the RT6585C, those are not related to the 5V from the USB-C AC adapter
The 1.3V on 5VALW, i still don't know why you have that...; there may be another fault somewhere

Voltage Inputs are VBUS_TBTA or VBUS_TBTB, straight from the USB-C ports (can be 5V at the start
Communication lines for negotiating power (with the AC adapter, or a device), are the TBTA/B_CC1 and TBTA/B_CC2
There's internal LDO regulators on the TPS65994 for 3.3V (VCC3_LDO_PD1) and 1.5V (VCC1V5_LDO_PD)
The TPS65994 can also route the +5VALW to the USB-C ports, when a device is plugged in (example: USB-C hub, USB drive, phone, external HDD/SSD, etc.), of course those 5V shouldn't go to the BQ charger IC, the MOSFETs stop that from happening
As when nothing is plugged in to the USB-C ports, with USB-C being bi-directional in terms of power, there should be no voltage there, whatever you plug in communicates first through the CC1 and CC2 lines

Main power rail is generated by the BQ charger IC, the voltage is the same as the battery voltage, see below; you'll never get 20V on the main power rail as it should be around 12.6-13V

Just to clarify, so when the TPS negotiates the 20 volts, it sends that voltage to the mosfets below it? I'm trying to see which way the current is supposed to flow? when working properly, what should the gate voltage be on those four mosfets? Two are high and two are low correct?

Depends on which USB-C port you connect the AC adapter, i'm using as an example the USB-C port JUC1, close to the HDMI port
VBUS_TBTA comes from the JUC1 USB-C port - PQ8304 - PQ8301 - fuse - inductors - input to the BQ charger IC
Gate voltage should be at least 2.5V higher than source, to turn on each MOSFET, that's what Vgs means in the datasheets for the MOSFETs

TBT_VSYS also loops back to the TPS65994, to sense "everything is OK, continue"
Only 2 MOSFETs are turned on, depending on which port you connect the AC adapter; even the design protects from someone trying to connect 2 AC adapters at the same time, turning on only 1 set of MOSFETs (PQ8304-PQ8301; or PQ8302-PQ8303) (Yes, some people tried that with 2016 MacBooks when they first started using 2-4 USB-C ports... )

In your laptop, the BQ creates the main power rail, which in your case is the same as battery voltage, without battery it should be around 12.6-13V
For "dead battery" support, the BQ25710 can temporally boost the 5V from the charger to around 12-13V, to allow for the "always on" 3.3V and 5V generated by the RT6585C to work (also 3.3V LDO and 5V LDO)
3.3V LDO (from RT6585C) supplies power to the EC (UE1), which in turn enables +3VALW and +5VALW
Now that the EC is powered, it can talk to the TPS65994 and says "hi, you can support these voltages, up to 20v"; as in this design, the TPS65994 doesn't have an external SPI flash memory with the "firmware", i don't know why Lenovo did this in your laptop, as on other models (ThinkPad) they used an external flash for the TPS firmware
That's why at the beginning, it did not negotiate the 20V unless the battery was connected (because the 5v didn't reach the input of the BQ charger IC), as the battery powered the main power rail

TPS65994 now speaks to the charger via the CC1 and CC2 lines: "hey, can you give me 20V please?"
Charger supplies 20V now

It's a complicated design for sure, too many steps where something can go wrong

[bogart219]

Wow, thanks Mich for the detailed explanation. Thats a lot to digest, I'm going have to think about that. So it appears that there is nothing shorted (at least drawing any current), its more like a component isn't working. I did order one of those RT6585C chips.
I did find 5 volts at different places but no 3.3 volts. what do you think I should try next?

[bogart219]

Hey Mich, off topic but can you tell me what you think of this ? A person on craigslist has a Dell inspiron 15 3000 intel 13 8th gen - $50. Here is what they said about it: "bought from friend who who passed at estate sale was given list of pass words none worked will be a great computer if you can unlock not stolen people live in my park".
Is there a way I can get around this? Fixing my Levono doesn't look too promising at the moment. Thanks again.

[m1ch43lzm]

Sent you a PM

[bogart219]

Well it seems we've come to a dead end as far as me being able to repair this laptop. It was a learning experience. Thanks to Mich for sticking with it this whole time and a shout out to Mon2 for his help in the beginning.
I'm taking it to a computer repair shop today and see if they can figure it out. I will post back when I have the final verdict. Thanks again!!