BQ24620: Nonsynchronous mode without conditions

Could you please probe the inductor current?

"Nonsynchronous is forced when the charging current is below 0.5A, when the battery voltage is below 2V or when the average charging current is lower than 0.125 A. "
This is correct, for last two conditions, it is easy to rule out. For charging current is below 0.5A, this 0.5A is cycle by cycle, which need to look at the inductor current.

Also, looks like you are using an USB input to charge a single cell battery. Can you probe the voltage at VCC tab and BAT? Also can you show LODRV waveform when the issue is occuring?

Hi Jing, thanks for answering.

Here goes the voltage measured directly on the sensor resistor (10 mohm), 10mV 10 uS per div.

The voltage is actually different to the one measured at SRP-SRN, I've missed the recommended layout for the resistor paths, ruining the sensing.

For not letting you blind about the layout, here goes a partial picture:

Here is VCC and Batt voltage, 500 mV 50 uS per div. (base levels are not shown in order to use a lower voltage division for a more precise measure)

Indeed, the circuit is made for being powered through a USB input, but for testing I'm using a workbench station (at 5V, I've tested 10V also). VCC (at CH1, mean level at 4.53V) looks very noisy.

Finally, here goes lodrv, which actually shows the 80ns pulse ( 2V, 100nS per div)

Then, I must certainly correct the measurement paths. Besides that issue, do you think that I must check something else?

Again, thanks for everything.

Are you able to probe inductor current? If not, then it will be very difficult to tell the cycle by cycle current...

Hi Jing, I'm sorry for not being clear.

The voltage measured directly on the sensor resistor (10 mohm) corresponds to the inductor's current. It actually shows that it goes below 5mV (.5A) on a cycle by cycle basis, meeting the conditions as you explained. That's clear then.

Here is attached again:   10mV (1A) / 10 uS per div.

Let me ask you, why would it not be able to sustain the synchronous mode? Where should I look? I'm close to fixing the paths at the sensor resistor, my guess is that that mistake introduces strong measurement noise and the fix should allow the chip to get into the synchronous mode, may I be missing something else?