NXQ1TXH5 issue in FOD detection and power transfer

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NXQ1TXH5 issue in FOD detection and power transfer

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hariharan_c
Contributor II

I am developing wireless charging application using NXQ1TXH5 application notes AN11775. I am observing the following problems after powering the device with transmitter coil (Abracon LLC Part# AWCCA-20N20H20-C01-B). Universal Receiver
( AllExtreme 5V 1000mAh Micro USB Wireless Mobile Charging Receiver Android Qi Charger Adapter Chip Compatible with Samsung Oppo Vivo Mi Motorola Nokia).


https://www.amazon.in/gp/product/B07TKVK6ZQ/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1

Observation:
1. RED LED is ON for 3 - 4 secs
2. GREEN and RED LEDs are blinking alternate for 3 times
3. RED LED is ON continuously

I have tested the with Transmitter and and Receiver coil with 1-2 mm distance. The device is not getting detected and no power transmission is happening.

Changes Made:

I have changed R8 and R9 resistors to 82K and 47K as per coil rating. Based the observation I understand that the controller is always in the Wait state. It is either receiver error of FOD error.

VFOD_TH is measured as between 2.4 V to 5 V. (Reserved). FOD is detected and it is always on the reserve state. We suspect that transmitter and receiver coil. Please advise if the selected Transmitter is compatible to the NXP controller. Any changes to be made in the schematics provided in the application notes.

Once we succeed in the building the prototype. We are planning to use this NXP controller series for our products. Kindly provide your support on this.#

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hariharan_c
Contributor II

Hello Jose,

Thank you for your response.

In the new board, we will try to disable the FOD and test the transmitter module and let you know the results.

Apart from disabling FOD and changing R8 resistor to match the coil specification, I hope there are no changes in the design (or) components in the demo board. Since we don't the demo board, we don't have any option to cross-check the design.

Before building the new board we want to have your confirmation on the circuit diagram, component list and Gerber.

https://www.nxp.com/downloads/en/design-support/NXQ1TXH5DB1401_Circuit_Diagram.pdf 

https://www.nxp.com/downloads/en/design-support/NXQ1TXH5DB1401_Component_List.pdf 

https://www.nxp.com/downloads/en/design-support/Gerber_files_NXQ1TXH5DB1401.zip 

Regards,

Hari

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reyes
NXP TechSupport
NXP TechSupport

Hi,

The wireless receiver you describe should work with our NXQ1TXH5DB1401 demo board.

 

From your description it looks like that the receiver is broken, so my recommendation is to check testing using another charger if it is working there.

From my experience, receivers are fragile and the USB connector easily breaks off.

 

Our application engineers have just tested it and as soon as you place the receiver, the green LED should start blinking.

pastedImage_1.png

Check the following:

- Is the supply voltage at the pins of the NXQ1TXH5 larger than 5V and is there not too much noise on it?

 

The problem you face is not related to FOD because in order to detect an FOD the charger must first start charging for several seconds.

 

For further debugging we have a debugging board available from Ecommerce:

https://www.nxp.com/products/power-management/wireless-power/nxq1txh5-plugin-board:NXQ1TXH5DB1355

You can download the manual from the website.

Regards,

Jose

NXP Semiconductors

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hariharan_c
Contributor II

Hello Jose,

Thank you for your immediate response.

I have checked the following.

1. Able to charge the mobile using the commercial wireless transmitter with receiver coil.
(AllExtreme 5V 1000mAh Micro USB Wireless Mobile Charging Receiver Android Qi Charger Adapter Chip Compatible with Samsung Oppo Vivo Mi Motorola Nokia)
2. Supply voltage at the pins of the NXQ1TXH5 is 4.48V

But the results are same. Unable to charge the mobile using NXQ1TXH5. The GREEN Led is blinking initially during the power on and later the RED LED is continuously ON.

I have planned to change the transmitter coil and check if there are any improvements.

Best Regards,

Hari

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hariharan_c
Contributor II

Hello Jose,

After changing the transmitter coil with Wurth Elektronik 760308101103 the behavior is same.

After Power ON.
1. RED LED is ON for few secs.
2. GREEN and RED LEDs are blinking thrice.
3. RED LED is continuously ON.

The behavior is same whether you connect the transmitter coil (or) not. Based on the observation the controller is in Wait mode. It is not recognizing the transmitter coil. As I mentioned earlier the receiver coil is working and tested with the commercial transmitter module.

The board has been built using the default resistor values mentioned in the schematics R7,R8, R9, R10, R11 of the application notes. Only R8 value has been changed to 82K ohms as per the Table 7 for Wurth Elektronik 760308101103.

What changes would you suggest in the to start power transfer ? Is there any changes in the schematics of the application notes. Is that disabling SPR/SPL would enable power transfer ?

Can you please advise, if I am missing anything ?

NXQ1TXH5 with screen printed wireless transmitter coil 

Also I would like to check whether NXQ1TXH5 was tested using screen printed wireless transmitter coil (printed silver conductive ink) with 6.3uH. Since in the final design we would be replacing the normal coil with the screen printed wireless coil.

Only for your reference https://www.nature.com/articles/srep15959 

 https://www.youtube.com/watch?v=mFhkMYKyrXw

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reyes
NXP TechSupport
NXP TechSupport

Hi Hariharan,

 

The supply voltage at the pins of the NXQ1TXH5 should be 5V is slightly more: a supply voltage of 4.48V is too low.

Use a AWG20 USB cable and a charger with cable compensation so that the supply voltage is also 5V at full load.

 

Please check if the NXQ1TXH5 on the board is not broken.

 

Are able to charge the mobile using our NXQ1TXH5DB1401 board?

 

Our applications engineers did some tests with a coil from AK stamping, there were no problems with it.

https://www.akstamping.com/wireless-charging1

 

Regards,

Jose

NXP Semiconductors

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hariharan_c
Contributor II

Hello Jose,

Thank you for the immediate response. I found that OUT2 (Pins 17 and 18) and GND (Pin 19) are short in the NXQ1TXH5. But there is no short in the board between these Pins.

Query 1) I don't understand how this short has happened within the IC, during the testing. Is this due to low voltage ? (or) any specific reason. We have already lost two IC's (NXQ1TXH5) without any external circuit defect. 

We don't have demo board NXQ1TXH5DB1401. We have requested to arrange for the demo board to NXP Bangalore, India through a local distributor for testing purpose. Looks like we don't have a sample board available at NXP India office at the moment. We want to test on the demo board before finalizing the design.

Query 2)

Regarding wireless transmitter coil, AK stamping coils are either copper (or) conductive metals through METAL STAMPING Process. But we are looking to integrate NXQ1TXH5 with the wireless charger coil printed on poly-carbonate (silver conductive ink). Do you have any compatible transmitter coils tested on NXQ1TXH5 ?

Query 3) We are planning to re-build demo board of “NXQ1TXH5DB1401” as per application notes. “AN11775” (https://www.nxp.com/docs/en/application-note/AN11775.pdf)

We are referring the Design Resources available in the NXP portal.

(https://www.nxp.com/products/power-management/wireless-power/nxq1txh5-wpc-1.2-qi-compliant-wireless-...)

As I mentioned we are using Wireless Transmitter Coil with specification of 6.3uH (or) Wurth Elektronik “760308101103” 6.5uH (https://katalog.we-online.de/pbs/datasheet/760308101103.pdf)

Can you please advise if there any other changes in the component list and circuit diagram apart from the changes mentioned in the Section 4.1 Table 7.0 of the application notes to change R8 (Resistor) for the recommended list of coils.

(https://www.nxp.com/downloads/en/design-support/NXQ1TXH5DB1401_Component_List.pdf)

(https://www.nxp.com/downloads/en/design-support/NXQ1TXH5DB1401_Circuit_Diagram.pdf)

We need your inputs before building the new board. Can you please check and provide your feedback ? 

Again thank you for your continued and timely support. 

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reyes
NXP TechSupport
NXP TechSupport

Hi Hariharan,

 

Please find the answer from our application engineers below:

 

Query 1) I don't understand how this short has happened within the IC, during the testing. Is this due to low voltage ? (or) any specific reason. We have already lost two IC's (NXQ1TXH5) without any external circuit defect. 

[A1] The only way to break the NXQ1TXH5 is to apply a too high voltage. That can be done by making the supply voltage too high, or by applying an external magnetic field to the charger coil.
The voltage on the pins of the NXQ1TXH5 may not be higher than 5.5V.

 

Query 2)

Regarding wireless transmitter coil, AK stamping coils are either copper (or) conductive metals through METAL STAMPING Process. But we are looking to integrate NXQ1TXH5 with the wireless charger coil printed on poly-carbonate (silver conductive ink). Do you have any compatible transmitter coils tested on NXQ1TXH5 ?

[A2] We haven't tested the IC with those kind of coils, but as long as the inductance is 6.3uH, I think it will work.

 

Query 3)

We are planning to re-build demo board of “NXQ1TXH5DB1401” as per application notes. “AN11775” (https://www.nxp.com/docs/en/application-note/AN11775.pdf)

We are referring the Design Resources available in the NXP portal.

(https://www.nxp.com/products/power-management/wireless-power/nxq1txh5-wpc-1.2-qi-compliant-wireless-...)

 

As I mentioned we are using Wireless Transmitter Coil with specification of 6.3uH (or) Wurth Elektronik “760308101103” 6.5uH (https://katalog.we-online.de/pbs/datasheet/760308101103.pdf)

 

Can you please advise if there any other changes in the component list and circuit diagram apart from the changes mentioned in the Section 4.1 Table 7.0 of the application notes to change R8 (Resistor) for the recommended list of coils.

[A3] Because you are using a small coil for low power,  you might easily trigger FOD, and therefore it might be good to disable FOD.

 

Regards,

Jose

NXP Semiconductors

1,593 Views
hariharan_c
Contributor II

Hello Jose,

Based on your inputs, we have built NXP (NXQ1TXH5) based wireless transmitter module and tested using Wurth Elektronik “760308101103” 6.5uH. The wireless transmitter module works well with both Android and iPhone mobile phones with the suggested inductance (6.3µH).   

 

We have built wireless transmitter coil using printed electronics on a flexible substrate using Wuerth Application notes on Wireless Power Charging Coil Changing Considerations.

We have tested Printed Wireless Transmitter Coil using different type ferrite sheets (thickness varying from 0.39mm - 2.50mm).  

Observation:

We observed that wireless universal receiver coil is detected by NXQ Transmitter module and indicator LED is blinking for few seconds. But there is no power transfer happens between transmitter coil (Printed electronics) to the receiver coil.

After analysis the FOD_E and FOD_T. Foreign Object Detection in an NXQ1TXH5/101 application is determined by the setting of two

parameters:

  • FOD_E (the equivalent AC loss resistance) = 280 mohms (recommended)
  • FOD_T (the power loss threshold margin that is considered acceptable).= 330 mW (recommended)

 

Expected FOD_E total resistance sums-up to ~195 + ~65 + ~20 = 280 mohms. (NXP Board Resistance+ Coil Resistance + PCB Resistance). For a typical coil that is used in the NXQ application that resistance is around 65 mohms.

Actual FOD_E (the equivalent AC loss resistance) = ~195 + ~ 19500+ ~20 = 19715 mohms. (19.7 ohms).

 

Summary of measurement of copper coil and Printed coil.

 

 

Input Voltage/

(Volts)

Inductance

(uH)

DC resistance

(as per datasheet)

DC Resistance

(measured with DMM)

Current (Amps)

PSupply

(Watts)

Ptxloss

(Watts)

Ptransmit =

PSupply- Ptxloss

(Watts)

Printed Coil

5

6.5

NA

19.5 ohms

0.24

1.2

0.005

1.2

Copper Coil

(760308101103)

5

6.3

150 mohms

 

1.3 ohms

0.06

0.3

0.04

0.3

 

Are we missing anything ? Please let us know your suggestion to improve the energy transfer using the printed wireless coil.

Regards,
Hariharan

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reyes
NXP TechSupport
NXP TechSupport

Hi Hariharan,

 

You received an answer from the NXP engineers in your open case #00240596.

If you have any further question regarding this topic, please use that case.

 

Regards,

Jose

NXP Semiconductors

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hariharan_c
Contributor II

Hi Joes,

Thank you for the response. We will check the how to reduce the resistance of the printed transmitter coil.

Best Regards,

Hari

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1,594 Views
hariharan_c
Contributor II

Hello Jose,

Thank you for your response.

In the new board, we will try to disable the FOD and test the transmitter module and let you know the results.

Apart from disabling FOD and changing R8 resistor to match the coil specification, I hope there are no changes in the design (or) components in the demo board. Since we don't the demo board, we don't have any option to cross-check the design.

Before building the new board we want to have your confirmation on the circuit diagram, component list and Gerber.

https://www.nxp.com/downloads/en/design-support/NXQ1TXH5DB1401_Circuit_Diagram.pdf 

https://www.nxp.com/downloads/en/design-support/NXQ1TXH5DB1401_Component_List.pdf 

https://www.nxp.com/downloads/en/design-support/Gerber_files_NXQ1TXH5DB1401.zip 

Regards,

Hari

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