BQ24616: When charging, DS1 is blinking

Hi Effi, 

Thank you for reaching out! 

What is the fast charge safety timer duration (what is the capacitance on the TTC pin)? 

Best Regards, 

Aya Khedr 

Thank you for answering,  we used 0.056uF for CTTC

Hi Effi, 

1- Could you please provide the full schematic of the BQ24616?

2- Are you able to replicate this on a BQ24616 EVM with your setup?

Best Regards, 

Aya Khedr 

BQ24616.pdf

Unfortunately, we don't have EVM available right now, but I can say this behavior occurs on multiple PCBs we produced.

From your answer i can understand this is not a normal behavior, is that correct? 

Hi Effi, 

Overall the schematic looks good! I do have a couple questions:

1. What is the inductance value of L3? 

2. Could you please elaborate on your design requirements for temperature qualification? Is JEITA compliance important?

The STAT1 LED behavior is not normal. We typically expect the following behavior indicating whether the device is charging or not. 

Could you provide a waveform of the STAT signals as well as Vin_PS when the blinking occurs?

Best Regards, 

Aya Khedr 

Hi Aya

1. 6.8uH 5.5A 46.8mΩ 20%

2. JEITA compliance is not required, the temperature qualification is in-home controlled environment, ~25C.

I could provide the waveform soon.

Do you think there is a mistake in the NTC resistors? (not connected, the resistor's value should simulate a fixed temperature).

TNX

Effi

Hi Aya, this is the STAT signal with Vin (Vin is constant)

Hi Effi, 

According to the resistor values below, the TS voltage should be about 2.1V, which falls into the normal range. What is the measured TS voltage when observing this behavior?

Best Regards, 

Aya Khedr 

• Hi Aya, thanks for noticing,  I changed the R32 value to be 4K, and now the TS voltage measured was 2.085V, according to the data sheet should be between T2 and T3, but still the STAT1 is blinking 

Interesting,  so do you recommend reducing ITERM by changing ISET2?

Hello, thank you for the help

I changed Iterm, by replacing R28 with 100 ohm, creating Iterm of 3mA. 

I measured the value, and all was correct.

This time the phenomenon was a little bit different:

I connected a battery with 11.8V (3 cells), the STAT1 was constantly ON as it should be, but after a few minutes, it began to blink again as before.

I suspect it started to blink when the battery voltage reached 12V, I will recheck it.

Do you have any new ideas of why this is happening?

Thanks 

Effi

Hi Effi, 

Thank you for the update. 

Could you provide a waveform of the STAT signals as well as Vin_PS when the blinking occurs?

Best Regards, 

Aya Khedr