BQ25171EVM：BQ25171EVM　Quick Start Guide Recommended Circuits

Hello

The TS resistor should be 10k, this should generate a voltage of 380mV at TS pin.   Normal operating range is 188mV to 1.04V for the TS pin.

On the EVM Fix position for JP6 is 10k for safe operating condition.

It looks like STAT1 / STAT2 indicate Normal Charge (High / Low) then transition to Recoverable Fault (Low / High).

Couple of things to check:

1.) Double check ISET=1.5k, VSET=18k, CHM_TMR=11k

2.) What is input voltage?

3.) What is output voltage?

4.) What load are you using for the test, battery simulator or battery?

Good morning.

Thank you for your response.

The following are the answers to your confirmation questions.

1. ISET=1.5k, VSET=18k, CHM_TMR=11k
Input voltage is 5V. 3.
The output voltage is 4.2V, but the battery voltage is 3.6V and the output voltage rises to 4.2V momentarily.
　　The output voltage is 4.2V, but after rising momentarily to 4.2V while the battery voltage is 3.6V, it drops to 3.6V in about 0.5 seconds. 4.
The battery is a 4.5V battery (Panasonic BK-3MCC x 3 pcs).

In addition to the above, we would like to add the following.

The TS resistor is 10kΩ, which is the same as the setting on the development board.
(JP6 is shorted to FIX side)
The resistor between TP4 and GND is 424Ω.
First of all, is this correct?
(I would like to isolate if it is not an initial defect)

I would like to add one additional point to the above description.
When JP6 is open, the resistance value of R20 is 10KΩ.
So, there is no problem with the mounted components.

Hello

Something appears to be setting a fault condition based on STAT1 / STAT2 and stops charge.

As a test try reducing charge current from 200mA (ISET=1.5k) to 100mA (ISET=3k) does this change the behavior.

Hello.

Thank you for your reply.
I have reduced the ISET charging current from 200mA (ISET = 1.5k) to 100mA (ISET = 3k) as you advised above, but the behavior did not change.

For the sake of posterity, I would like to know if you have tried the ISET change.
Is it my understanding that the TS is initially OK?

Hello

user4863518 said:

For the sake of posterity, I would like to know if you have tried the ISET change.

We do not see the problem you are describing. Yes have tested the BQ25171 at mult charge currents.  I have tested this device in 3S NiMH and other configurations.

STAT1 and STAT2 are indicating a Recoverable Fault (Low / High) -- Fault could be TS but you have 10k resistor connected and voltage on the TS pin is around 380mV, this is a safe condition will not be a problem.

The battery voltage sounds odd, expect some increase in NiMH battery voltage when fully charged followed by decrease.  But this will take 15 to 30 min and you are seeing less than a min. Reducing the charge current (ISET) will reduce this voltage rise. Your test did not show any change.

Thank you for your response.

First of all, I have confirmed about your answer if you have tried to change the ISET.

In my case, I'm having trouble testing in the initial state after purchase, rather than post-education.

Is the resistance value between TP4 and GND in the initial state of TS 424Ω correct?
' (I have confirmed this above, but since there is no answer to the resistance value, I am asking again.)

We believe that there is no problem with the lithium-ion battery itself, as it can be recharged by other recharging methods.
　(We have also tested batteries in the initial state of purchase after discharging them in a dedicated jig.)

Hello

The Test Procedure for TS requires that the Jumper be placed in the Fix (10k) before shipment. 

This would be a safe condition to start evaluation.

""Is the resistance value between TP4 and GND in the initial state of TS 424Ω correct?""" -- Bill J - No this is not a safe value, will set hot temp fault.  But the JP6 jumper would need to be in ADJ (Adjust) position and R19 set to 424 ohm. 

Hello.

The above answer is that the TS4-GND is between TS4 and GND when shipped.
10kΩ between TS4 and GND when shipped?
(I'm sorry if I'm taking this the wrong way)

Hello

See below from the EVM User's Guide.  

Shorting Jumper on JP6 should be in the Fixed position, this will connect 10k to the TS pin (Pin 4) and provide a safe condition.  

user4863518 said:

10kΩ between TS4 and GND when shipped?

Yes -- will be 10k to GND when shipped.  "TS4" should this be TP4?

Hope this helps.

Hello.

Thank you for your response
I have checked your description.
What I would like to confirm is that in its normal state as shipped
I am asking you to confirm what is the correct resistance value between TP4 and GND.

Hello

TP4 to GND -- the resistance reading can be inaccurate due to TS circuits inside the BQ25171.  Different meters can give different readings. 

What is the TP4 voltage in the Fixed position (10k resistor)?

If it is 380mV board is OK. 

Hello.

Thank you for your answer.
The 380mV above is a peripheral connection condition.
Is it when the battery is not connected?

Hi 

The Evaluation Board TS pin has the option to connect to external NTC resistor in the battery pack thru connector J2.  The on board resistor network should be disconnected, JP6 open.

If no external NTC resistor is used then JP6 shorting jumper should be populated.  Fixed Position = 10k will is a safe conditions and voltage at TP4 - 380mV.  ADJ position provides the option to change TS Resistance / Voltage  using R19.

Thank you for your response.

In the environment that you taught me above.
BAT is not connected
JP6 is FIXED (10kohm) and shorted.

The voltage between TS4 and GND is 250mV.
(confirmed by oscilloscope and tester)

I have not made any modifications since the initial purchase.
I have not made any modifications since the initial purchase, but I wonder if the difference in these values could be the cause of the difference.

I would like to double check the test setup and also confirm of the EVM.

EVM configuration

• Jumper configuration – see below table from the user’s guide
  • This configuration is a single cell Li-Ion (4.2V) charge current 400mA
• To configure for NiMH
  • S1 (VSET) -- 24k position 3 for 3-cell NiMH
  • S2 (CHM_TMR) -- 18k position 3 for 10hr NiMH
• To configure for 200mA
  • JP3 from Fixed (400mA) to ADJ
  • Adjust R22 for 200mA, 1500 ohm

Thanks for the answer.
I checked the following EVM settings for NiMH.
As a conclusion, the charging operation could not be performed
because the voltage between TS and GND is 66mV.
I would like to double check the test setup and also confirm of the EVM.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
EVM configuration
- Jumper configuration - see below table from the user's guide 4.
This configuration is a single cell Li-Ion (4.2V) charge current 400mA
- To configure for NiMH
S1 (VSET) -- 24k position 3 for 3-cell NiMH
5.S2 (CHM_TMR) -- 18k position 3 for 10hr NiMH
- To configure for 200mA
JP3 from Fixed (400mA) to ADJ 1.
Adjust R22 for 200mA, 1500 ohm

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Thanks for confirming -- do you want to try another EVM?

Am I correct in interpreting that as a new purchase?
Or should I explain the confirmation to the original purchaser and request a replacement?

I will contact you.

What exactly should we do here?

I will set up a PM conversation, look for msg from the E2E system.