This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMR61428 connected to BQ24195

Other Parts Discussed in Thread: LMR61428, BQ24195

Hi,

We have connected the output of LMR61428 (5V) to BQ24195 input via pfet.

 

The microcontroller senses the solar voltage continuously and upon good solar voltage, it enables the PFET so that the battery can be charged via solar power.

 

The LMR61428 output when tested on resistive load can deliver around 250mA to 300mA in good sun conditions.

 

BQ24195 has input current limit settings of 100mA, 150mA, 500mA ...... The customer  needs maximum possible charging current so that marketing team can claim faster charging of the product battery.

 

When we are setting BQ24195 to 500mA or above, the LMR61428 output goes into hiccup or keeps on restarting. We can also hear a peculiar recurring chirping kind of sound and the charging just does not happen. The LMR61428 output voltage also keeps on hunting.

 

Please suggest a way out to achieve maximum current or else we will have to restrict the charging to 150mA max. This would waste the capacity of solar panel which yields higher output.

Regards

Atul Bhakay

  • Atul,We understand your question. We will get back to you soon. -Yang
  • Hello Atul,

    As Yang said, we believe you could be hitting the current limit and because of which your output gets limited. Would you please tell us your VIN range and show a design schematic? This device operates on a gated oscillator method. The duty cycle of the conversion is always fixed to 70%. Therefore the output has a small low frequency ripple on it all the time. Another possibility is that If you VIN is close to the 70% (min limit of 60% over temp) DC and then when you add a heavier load, it could hit that mark and then cause the output not to be regulated too.

    Regards,
    Akshay