BQ501210: Does not transfer 15W(12Vout receiver) only <5W (5Vout receiver)

Jens Riester

Part Number: BQ501210
Other Parts Discussed in Thread: BQ51025

Hello,

we got an issue with our own design of the bq501210 wireless charger. Our design ist pretty much similar to the EVM board.
Our Problem is, when we pair it with an IDT 15W receiver it only transfers 2-4W and the receiver only make 5V output.

With the EVM board everything went perfect and we got 12V out at the receiver.
Maybe the mode switches from 15W to 5W?
We excluded some parts of the evm circuit. For example the USB stuff with the D- and D+ resistors. But we tested this change at the EVM Board, it still worked.
Does this make a difference?
Moreover we canged little things like values of capacitors, but only exchanged them, for example, a 47µ with 5 10µ. Should be fine?
Which parts of the circuit are essential for this different transfer modes? Are there certain values who are responsible for the different transfer modes?

Thank you in advance!

over 6 years ago

0 Bill Johns over 6 years ago

TI__Guru 65746 points

Hi
This could be the FOD ckt---if FOD is not working or disabled the bq501210 will not enter 15W but stay in 5W mode.

0 Jens Riester over 6 years ago in reply to Bill Johns

Prodigy 50 points

Hello Bill,

thank you, what is "ckt"? We already checkt the FOD. FOD works and also recognize foreign objects, such as metal.

The resistors are the same values as in the evm board.

What else could be wrong?

Kind regards

Jens

0 Bill Johns over 6 years ago in reply to Jens Riester

TI__Guru 65746 points

Hi
Check if the green LED is in fast blink (15W) or slow blink (5W) power transfer mode, see table 3 in the data sheet.

UPDATE AUG 16---Fast blink will apply only to operation with bq51025 and 10W mode. Also slow blink with the bq51025 indicates low power 5W mode. With a WPC 1.2 RX the LED will only slow blink independent of the output power.

The FOD circuit will be R8, R16, R47 and R48. Input to the ckt will be current sense at Pin 5, voltage sense at pin 63.
Input voltage should be 15V to 19V for 15W.

0 Jens Riester over 6 years ago in reply to Bill Johns

Prodigy 50 points

Hi,

The green LED is fast blink. All the resistors you mentioned are in the circuit, this point should work.

Pin5 and pin 63 is connected to the right place. Is it important to keep this lines really short?

They aren't really long, but might be a little longer than in the evm.

What else is important regarding this issue?

Kind regards

Jens

0 Jens Riester over 6 years ago in reply to Bill Johns

Prodigy 50 points

Hi,

we got the issue, it was our mistake.
We picked the wrong diode D11 at PWR_UP. The voltage on the PWR_UP Pin was to high and it damaged the IC.
Thanks for your help!

Best regards
Jens

0 Bill Johns over 6 years ago in reply to Jens Riester

TI__Guru 65746 points

Thanks for the update.

0 Jens Riester over 6 years ago in reply to Bill Johns

Prodigy 50 points

Hi,

I got a further question.

We are able to transfer >10W, but the LED ist not fast blinking.

Does it only blink fast, when operating with the bq51025 in 10W mode or also with other WPC 1.2.2 compliant receivers.

Cause the index (1) of table 3 says, when its operating with the bq51025.

For example the IDT P9221, we can transfer more than 10W but it's not fast blinking.

Thank you in advance.

Kind regards

Jens

0 Bill Johns over 6 years ago in reply to Jens Riester

TI__Guru 65746 points

This is correct.
Fast blink will only apply to the bq51025 in a 10W mode. I have revised the earlier post.

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BQ501210: Does not transfer 15W(12Vout receiver) only <5W (5Vout receiver)