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I got my desktop charger today and unpacked it only to rip it aparts to check whats inside.
By first view theese are the highlights:

The dock connector is 40 pins
Dock connector is on a separate small pcb with a 40 pin board to board connector to a larger board.
On this small pcb is a 12 pin MLF package marked:
AAU
NAD

Probably has a ground pad underneath.

The main pcb has a few more circuits and connectors on it.
There is a micro usb, a full size master usb, audio out and microphone jacks. A bit more exiting there is room for a HDMI connector as well there with unpopulated spaces for line filters and a hdmi circuit. By first look it seems to be a displayport or MHL to HDMI bridge chip of some kind. I is TQFP-48 package.
edit:
It seems to be a PI3VDP411LS from pericom
http://www.pericom.c...PI3VDP411LS.pdf

It is a displayport levelshifter / bridge to HDMI. It is the only 48 pin package I have found to match the input with the differential pairs.

The power supply is 20 VDC 65 Watts. It does not seem like the center connector is connected. The connector is the standard "IBM" charger, outer case ground, inner case + 20 vdc, center pin power diag.

There is a fet transistor between the dock connector and the psu marked FA1K18 and it is controlled by some regulator marked 920A4 in a SOT-223 package. The 20 VDC goes in on pin 2 and the tab on it.

the HDMI chip has differential pair inputs on pin 47,48 - 44,45 - 41,41 - 38,39

I will do my best reversing the whole schematic for this unit and split it into parts so we can make other chargers and hopefully add HDMI to the dock.

Pinout Docking Connector Thinkpad Tablet

1 charge 2 gnd
3 charge 4 hdmi pin 44 In D3-
5 Charger control (to pq2) 6 hdmi pin 45 In D3+
7 hdmi VDD 3.3V 8 gnd
9 gnd 10 hdmi pin 47 In D4-

11 USB Micro D- 12 hdmi pin 48 In D4 +
13 USB micro D+ 14 gnd
15 USB Master D- 16 nc
17 USB MAster D+ 18 nc
19 gnd 20 hdmi pin 29 SDA

21 gnd 22 hdmi pin 28 SCL
23 hdmi pin 41 IN D2- 24 hdmi pin 7 HPD_Source
25 hdmi pin 42 In D2+ 26 gnd
27 gnd 28 audio out L
29 hdmi pin 38 IN D1- 30 audio out R

31 hdmi pin 39 IN D1+ 32 headset inserted switch
33 gnd 34 mic inserted switch feed
35 USB micro + 36 mic inserted switch
37 gnd 38 mic tip
39 + 5V to usb master 40 mic ring


Pinout AAU chipAAU chip is audio amp.
audio out
pin 10 ring
pin 11 tip
pin 2, 7 gnd


Charger stuff :
The supplied DC apater is 20Volt 3.25Amps
In the dock there is a voltage regulator PV1. It is a 3.3 V LDO Tab has 20 volts in and pin 3 gives 3.30 Volts out.
There is also a FET in SSO8 (?) package. It is controlled by 2 transistors and works only as a switch.
On the base of PQ2 (pin 1, I guess it is the base) there is a float of 3.30 volts when there is nothing in the dock. The FET is OPEN and no voltage to the charger pins.
When grounding PQ2 pin1 (dock pin 5) the FET CLOSES and the charger outputs 20,5volts which basically is the same as dc power into the dock.

Now I am just waiting for the TPT to get fully charged so I can measure if there is any difference when fully charged.

Note:
By charging at 20 volts instead of 5 volts I understand why the charger only uses 2 pins into the TPT.
At 20 volts you can transfer 4 times the energy instead of just charging at 5 volts from USB powers. There is no need for step ups to charge the LI-Po battery as it would need more than 5 volts.

This is the schematics of the charger part:

www.r-888.com/tpt/schema.pdf

I am not sure of the 2 transitors if they are pnp or npn yet but the rest is how it is.
The original mosfet is a P-channel AON7403.
The regulator is just any 3,3 volt LDO.

The TPT charger control pin 5 gets a 3,3 volt float via the resistor to the left in the schematic. When it is connected the TPT grounds the pin and the FET lets current through.
 

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ZebCrs said:
I got my desktop charger today and unpacked it only to rip it aparts to check whats inside.
By first view theese are the highlights:

The dock connector is 40 pins
Dock connector is on a separate small pcb with a 40 pin board to board connector to a larger board.
On this small pcb is a 12 pin MLF package marked:
AAU
NAD

Probably has a ground pad underneath.

The main pcb has a few more circuits and connectors on it.
There is a micro usb, a full size master usb, audio out and microphone jacks. A bit more exiting there is room for a HDMI connector as well there with unpopulated spaces for line filters and a hdmi circuit. By first look it seems to be a displayport or MHL to HDMI bridge chip of some kind. I is TQFP-48 package.
edit:
It seems to be a PI3VDP411LS from pericom
http://www.pericom.com/pdf/datasheets/PI3VDP411LS.pdf

It is a displayport levelshifter / bridge to HDMI. It is the only 48 pin package I have found to match the input with the differential pairs.

The power supply is 20 VDC 65 Watts. It does not seem like the center connector is connected. The connector is the standard "IBM" charger, outer case ground, inner case + 20 vdc, center pin power diag.

There is a fet transistor between the dock connector and the psu marked FA1K18 and it is controlled by some regulator marked 920A4 in a SOT-223 package. The 20 VDC goes in on pin 2 and the tab on it.

the HDMI chip has differential pair inputs on pin 47,48 - 44,45 - 41,41 - 38,39

I will do my best reversing the whole schematic for this unit and split it into parts so we can make other chargers and hopefully add HDMI to the dock.
Hacking hardware? This community is awesome!
 

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I think I found the parts for the female and male docking port connectors. The features on the pictures look pretty near identical to the docking port on the TPT. Hopefully this helps in your efforts to figure out how we can make a homemade charger. We would just need to reduce the voltage/amps from the psu to what the dock outputs, unless the chip also sends a sort of data signal to tell that its providing juice.

female: http://www.mouser.com/ProductDetail/JAE-Electronics/DD2R040HP2R1000/?qs=sGAEpiMZZMvd2mIcYG7oaBPmHh3ZnC2j%252bc%252bxfTSM%2fuw%3d
male cable: http://www.mouser.com/ProductDetail/JAE-Electronics/DD2P040MA1/?qs=sGAEpiMZZMvd2mIcYG7oaGMGyOaUl6J1nIDf0saGL3I%3d
male connector: http://www.mouser.com/ProductDetail/JAE-Electronics/DD2B040HA2R500/?qs=sGAEpiMZZMvd2mIcYG7oaGC50BWp6JGtnzFW1qxXQKU%3d

I could be wrong, but hopefully this helps
 

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I'd love to be able to make a custom cable to provide audio out and charging for use in my car mount... It looks kind of messy with separate wires coming out of the side. Looking forward to seeing if you can come up with a pinout!
 

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Cool, I just ordered a couple of sets of connectors of the variants they had. They should arrive on Friday.
Hopefully I will have time tomorrow to map out most of the connector. I will do some hires scans of the boards.
I have uploaded some pics here :http://www.r-888.com/tpt/pics
It's times like these I wish I'd studied electrical engineering instead of mechanical, but if there's anything I can do to help moving forward (another part hunt like before) please let me know. There are many cool possibilities if we can figure out how to recreate the same circuit.
 

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ZebCrs...really appreciate your willingness to take your own dock apart. Would you agree that the easiest thing to tackle first would be figuring out the power circuit? Perhaps just a charger cable that ties right into the positive and ground of the 65 watt psu and goes right into a circuit that can feed one of those male dock connectors.

Since you have the dock and I would assume also a voltmeter, you can probably figure out what the circuit needs to entail pretty easily. I've got a laser printer and I've heard of people etching via a laser printout. If we can come up with a design and what components need to go on it, I feel like we could make a prototype charger for <$35 including non-lenovo 65 watt ac adapter.
 

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My goal is to hopefully help create a charging cable with the 65 watt 20volt psu that will work with the 40 pin docking port. Not sure how the LDO voltage regulator and fet transistor circuit would be put together though. We found the connectors and I think I found an appropriate LDO Volt. Reg. but have not identified a proper FET transistor. We know which pins need the positive and ground from the charger as well.

Need some assistance with the circuit design (though I don't think it's that complicated) and the FET transistor and we should be able to create a charger as good as the dock.
 

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Discussion Starter · #13 ·
I am trying to figure out how the charger is started up now. Without the pad connected to the dock the regulator and connected fet does not start up. There is 1 control signal from the pad to some circiutry around the regulator.
I have to get my scanner working and do some scans of the boards. I have mapped out most of it now and will add some comments on the scans. Maybe I get my connectors in today or tomorrow:)
 

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Discussion Starter · #14 ·
Regarding the voltage regulators. We just have to find a regular that works like the original setup. Find one with all integrated instead of external fet to control power flow. It is a bit more easy and a bit more expensive. The connector for the charger is really expenise anyways. It is about 10 € and the shipping is about 35€ !
But as soon as I can confirm the connectors are the correct ones we can start finding a cheaper supplier on them.
I can do a small schematic and a pcb that accepts most laptop chargers and 12 V dc car input to make it it more all-round usable.
 

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Discussion Starter · #15 ·
I got the connectors in my workshop here now and can confirm it is the correct ones.

DD2P040MA1 from JAE engineering is the correct cable connector. The Mouser part no is : 656-DD2P040MA1

It is 9.08€ a pcs. and down at 4.82€ in 1000x. They have 111 pcs. in stock atm.
 

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MY DD2P040MA1 will probly come in tomorrow. Assumed it was the correct part. I'm going to try and get an old Lenovo psu from the tech guys at my workplace to avoid paying for that too.

I guess I'm not surprised that there is a control signal to the charger. I wouldn't know if we need to replicate this or if it could just be always on. Perhaps it's an easy addition to the final pcb anyway, sounds like you are working to try and find out. If there's anything I can help with, let me know!

Also I think it would be good to be able to use the standard Lenovo 90 watt 20 volt laptop charger, since they are cheaper on the second hand market than the new 65 watt one.
 

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I got the connectors in my workshop here now and can confirm it is the correct ones.

DD2P040MA1 from JAE engineering is the correct cable connector. The Mouser part no is : 656-DD2P040MA1

It is 9.08€ a pcs. and down at 4.82€ in 1000x. They have 111 pcs. in stock atm.
So, correct me if I am wrong, but could we use the DD2P040MA1 connector to make a cable for the dock port. Would the other end of the cable be simply a USB male connector that we could connect to the current USB charger we received with our TPT's? Or is that adapter not fit to output what the DD2P040MA1 connector needs?
 

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So, correct me if I am wrong, but could we use the DD2P040MA1 connector to make a cable for the dock port. Would the other end of the cable be simply a USB male connector that we could connect to the current USB charger we received with our TPT's? Or is that adapter not fit to output what the DD2P040MA1 connector needs?
No this is basically replicating how the dock charger charges without having to buy the dock. This charger would be using a 65 watt or 90 watt, 20 volt AC Lenovo Power Adapter (brick) just like the dock does along with a 40 pin cable connector (see posts above) and some associated circuitry (Voltage Regulator) to bring the 20V down to 5V. It's not as simple as you are thinking. It will take some soldering, pcb board fabrication, etc.
 

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Discussion Starter · #19 ·
You would need a power supply that can deliver more voltage and more current than the original. The USB standard does not allow that much power.
You would need a power that can give at least 2,5 Amps.
The DD2P040MA1 connector is just a connector. You would still need a voltage regulator and some signaling from the tpt to the charger circuit.
Still working on that part. Between this I actually have to work too ! :)
 

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You would need a power supply that can deliver more voltage and more current than the original. The USB standard does not allow that much power.
You would need a power that can give at least 2,5 Amps.
The DD2P040MA1 connector is just a connector. You would still need a voltage regulator and some signaling from the tpt to the charger circuit.
Still working on that part. Between this I actually have to work too ! :)
Don't we all....it's such a bother
 
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