EMB1499Q： emb1499Q can be charged, but not discharged

Hello, 

Thanks for your question. The EMB1499Q device was designed to be used together with EMB1428Q device, and not by itself. There is a handshake that needs to happen between these devices through the EN, DIR, DIR_RT, DONE and FAULT signals to be able to operate and communicate fault conditions. 

Best regards,

Leslie

hi Leslie,

We've tested that，EMB1499Q can be used by itself，Just give these two signals，EN and DIR, charge and discharge both work well.

Now this test board， schematics not be changed, only PCB be changed, but it can charge，can't discharge.

Best regards,

Jun

Hi Jun, 

If I understand correctly, you designed a board that works ok (both charge and discharge) and then you designed a 2nd board in which only charge works. Is this correct?

What exactly did you modify on the 2nd PCB? Please review the "PCB Layout Recommendations" section of the device datasheet.

Regards,

Leslie

Hi Leslie,

You understand exactly.

2nd PCB adjusted the position of the components，The degree of adjustment is minimal.

Device datasheet, which has been studied over and over again，Nothing was found to be wrong.

Regards,

Jun

Hi Jun, 

Does this happen on only 1 board or do you have multiple boards that have the same issue? 

Regards,

Leslie

Hi Leslie,

It's the same phenomenon on multiple boards.

Regards,

Jun

Hi Jun, 

I would recommend to check the FAULT[2:0] pins on the device to see there is a fault happening. Description can be found in the "Fault Detection and Fault Codes" in the datasheet. 

You can also use an oscilloscope to compare the signals from the working board and the not working board and identify any differences.

Best regards,

Leslie

Hi Leslie,

I had  checked the FAULT[2:0] pins, The measurement is [000], It means no FAULT.

I've also measured waveforms on an oscilloscope，

Below is the waveform of the HS1 and HS2 when open discharge:

Below is the waveform of the HS1 and HS2 when open charge:

The waveform of discharge does have a problem by the results, but I don't know why.

In addition, I'll describe the phenomenon again : when discharging, the Secondary Side（cells） is already consuming energy，but Primary Side is no power.

Best regards,

Jun

Hi Jun,

Thanks for the data. I'll check the plots and get back to you within the next couple of days.

Regards,

Leslie

Hi Jun,

It's interesting that you are not seeing any fault in the device. The discharge signals do look different than expected. Since the device is not triggering a fault, I would recommend to focus on the board components or any traces/connections that might be different between your new board (not working board) and your older version of the board (working board) by testing both. I recommend to compare the signals on both working and non-working boards to find any differences and trace the problem that way. You can use signals on figure 7 in the datasheet as to how the 4 signals (GATE_LS, GATE_HS1, GATE_HS2, PWM_CLAMP) need to look when discharging.

Regards,

Leslie