BQ 500211：I want to know the correct waveform of bq500211

ZheTao Xie

Prodigy 240 points

Other Parts Discussed in Thread: BQ500211, TPS28225, BQ51013B

零件编号：BQ 500211

HELLO！

I'm testing the board I designed based on bq500211.

But my waveform seems to be wrong, causing my TX coil to not work. I want to know the correct waveform for each pin.

Best regards from China,

Zhetao Xie

over 4 years ago

0 Bill Johns over 4 years ago

TI__Guru 65816 points

Hello Zhetao Xie

I have some troubleshooting info and will attach it to this post.

If you have a specific waveform you are concerned about I can provide more info.5670.bqTESLA FAQ--TX Trouble Shooting Guide.pdf

0 ZheTao Xie over 4 years ago in reply to Bill Johns

Prodigy 240 points

HELLO bill！

This is my inverter circuit. But when I turn on the power, pin 1 (ugate)and pin 8(phase) of tps28225 will be short circuited.At the same time, NMOS has no short circuit.

Best regards from China,

Zhetao Xie

0 Bill Johns over 4 years ago in reply to ZheTao Xie

TI__Guru 65816 points

Hi Zhetao

Check the connection of C107, it should connect from U10-2 to U10-8. It may be connected to R100.

0 Bill Johns over 4 years ago in reply to Bill Johns

TI__Guru 65816 points

Hi Zhetao

Any update on this one?

0 ZheTao Xie over 4 years ago in reply to Bill Johns

Prodigy 240 points

HI Bill！

I Check the connection of C107, I found that I uploaded the wrong schematic.The connection of the circuit is correct.

After checking the circuit, I found that the turn-on delay time of my NMOS is too long, which is much longer than the ugate turn-off

propagation delay of tps28225. After I replaced the NMOS, the circuit worked normally.

Thanks for your help.

Best regards from China,

Zhetao Xie

0 ZheTao Xie over 4 years ago in reply to Bill Johns

Prodigy 240 points

Hi Bill！

I have a new problem.When the device is in standby mode.

Why the period of DPWM signal is different from that of SLEEP?

Why is the waveform of 3v3_VCC unstable?

This is the waveform of SLEEP signal.(Its period is 360ms.)

This is the waveform of DPWM-A signal.（Its period is 4.6s.）

This is the waveform of 3V3_VCC signal.（Its period is 340ms.）

This is the circuit diagram.

They work normally when they are under load.

Best regards from China,

Zhetao Xie

0 Bill Johns over 4 years ago in reply to ZheTao Xie

TI__Guru 65816 points

Hello

This is a power saving mode used during standby. The unit will turn off the 3.3V if no RX is detected.

The waveforms look normal.

0 ZheTao Xie over 4 years ago in reply to Bill Johns

Prodigy 240 points

HI Bill！

1.I know this is a power saving mode used during standby.

But I don't understand why the waveform of 3V3_VCC is irregular. Is it normal?

2.Another question, is the comm signal of bq500211 correct？

3.Last question, is the comm signal of bq51013b correct？

I'm sorry I submitted the same question twice yesterday.

Thanks for your help！

Best regards from China,

Zhetao Xie

0 Bill Johns over 4 years ago in reply to ZheTao Xie

TI__Guru 65816 points

Hi Zhetao Xie

The first photo is 3.3V bus --- this is normal behavior, voltage is off during the low time and bus is high impedance slight changes in load will result in large change in low level.

The 2ed and 3ed Comm photo -- This looks normal, comm is occurring at a about 2kHz and is modulation of the operating freq. What is captured in the scope shot is operating freq.

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BQ 500211：I want to know the correct waveform of bq500211