BQ25170: charger not working

Hi bill, some additional information. The battery is not connected and I'm trying to power the circuit via 5v usb charger. 

Hi Pragash

Couple of things to look at:

1.) If the battery is not connected the unit should work but will have a sawtooth output as it goes from charge complete to recharge.

2.) If the battery is not connected the TS pin will be open and unit will set Cold fault.  Try connecting 10k resistor to TS pin.

• If I connect 10k to ts, what should I do with 69k and 2.3k? Should I connect 10k in series or parallel in the TS line? 

Connect the 10k ohm resistor at the battery pack TS pin and ground.

I have to replace 69k with 10k and 2.3k with 0ohm? 

Will the battery charger work if I plug in the battery with 10k shunt? 

I want a ts configuration that works with and without battery. Could you also please explain how the resistor value affect the temperature sensing? 

Hi Pragash

pragash sangaran78 said:

I have to replace 69k with 10k and 2.3k with 0ohm? 

Yes - that would be a good test condition to get the unit up and running. 

pragash sangaran78 said:

Will the battery charger work if I plug in the battery with 10k shunt? 

No-- it is very close to the hot fault threshold.  For testing you could remove R14 (2.3k)  TS would be in a safe condition with or without the battery.

pragash sangaran78 said:

want a ts configuration that works with and without battery. Could you also please explain how the resistor value affect the temperature sensing? 

Sorry do not have a configuration that would work with or without a battery.  The above will not use NTC in the battery pack.

You said if I remove 2.3k, ts will be in safe condition with or without battery. Removing 2.3k means replacing it with 0ohm or disconnecting ts from the battery ? 

By disconnecting ts from.the battery, the battery charger won't be able to sense temperature of the battery correct? What is the impact to the battery safety? Disconnecting ts is the only way the charger work with and without battery simultaneously? In this configuration, shunt 69k is still.there right ? 

Is there any charger chip that can work with and without battery and sense battery temperature effectively? Or this kind of sensor is non existent! 

Hi Pragash

"You said if I remove 2.3k, ts will be in safe condition with or without battery. Removing 2.3k means replacing it with 0ohm or disconnecting ts from the battery ? " -- Bill J - Yes removed 2.3k, OPEN, the R14 position is not populated.

"By disconnecting ts from.the battery, the battery charger won't be able to sense temperature of the battery correct? What is the impact to the battery safety? Disconnecting ts is the only way the charger work with and without battery simultaneously? In this configuration, shunt 69k is still.there right ? "

Bill J -- As a test to get the charger up and working 69k to 10k and 2.3k open.  Will allow you to test the circuit with or without a battery. BUT cannot configure the unit to use the Battery TS and No Battery.  

"Is there any charger chip that can work with and without battery and sense battery temperature effectively? Or this kind of sensor is non existent! "  

Bill J -- Yes see the BQ24040 section8.4.9 that describes the Termination and Timer Disable Mode (TTDM).

hi Bill Johns,

I want to report another issue. The ISET is set to charge the battery with the highest current. However, the battery is not getting full even after days of charging. Do you know why and how to solve this issue? I'm using a high-current Samsung USB-C charger. 

Hi Pragash

The BQ25170 has a 10 hour safety timer. If charge does not complete the unit will turn off.  If unit is in thermal regulation with reduce output current the timer is doubled, max 20 hour.  Charge needs to complete in 20 hours or less.

Check the ISET pin voltage, if unit is in current regulation voltage will be 1V.  If unit is in thermal regulation the voltage will be less tan regulation.  

Note during constant voltage phase current is reduced and ISET voltage is less than 1V.