BQ24070: BQ24070 Charging Issues

Hello,
Do you have a protector on your battery?

Hi

Yes i do, but i see 0.63 V when battery is not connected on VBAT, while in some IC it shows 4.2 V.

Even when battery is connected still shows 0.63V

Thanks

Vaibhav bansal

Hello,
Can you post a scope capture of what you see on the BAT pin when battery is not connected.

Hi

There are snapshots below with two PCB one which is working perfect and which has issues.

As i said working one provids 4.1 V output while other provides 0.6V in same condition.

PFA of the snapshots.

Thanks

Vaibhav Bansal

Hello,
I actually meant a scope capture on an oscilloscope of the BAT pin of the BQ24070. That would be helpful in diagnosing what's going on with the device.

Hi

Scope capture of the BAT pin you had asked for. PFA for the same. I think this might help. Probes are attached between VBAT and GND pin.

Thanks

Vaibhav Bansal

Hello,
Sorry for the late reply. I was out of office. This seems to be when the battery is connected. Can you show the scope capture of the BAT pin when the battery is absent?

HI 

The scope capture is this when battery is not connected. If you need any kind of confirmation I will send a photograph for the same.

Thanks

Vaibhav Bansal

Hello,
It is hard to see the reference zero for the measurement. Also can you reduce it to about 500mV per division.

Hello

PFA for the scope you had asked for, with the photograph showing IC connection with Oscilloscope.

Thanks

Vaibhav Bansal

Hello,
What is the current into the BAT pin when only VBAT is present with no load on OUT.

Hi



When IC is working fine the current is 1.4A in case of no load. When issues is there the current is in mA or 0 A when no load is connected.

When IC is working fine the current is 1.4A in case of load connected. When issues is there the current is in mA or 0 A when load is connected.

Max current requirement on load side is PEAK of 125mA for 500 ms and average current requirement is 20mA.

Vaibhav,
is this with VIN present? Can you check with VIN NOT present. The current should be in the uA range

Hi 

I had tested again. The result are as follows.

1. When VIN is not present battery is working fine. LOAD get enough current for its fine operation.

2. When VIN is present, VIN is providing the LOAD current but in that CASE Battery charging voltage goes down to 0.6V and Current goes in uA.

Hello,
What i meant was the current into the BAT pin when VIN is absent with no load on OUT pin.
Check the CE pin to ensure it is pulled high.
Have a SMU or Power supply that can sink current on BAT pin instead of a real battery. This will remove the protector as a variable in causing issues.