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.

BQ24610EVM: The BQ24610EVM is not charging the battery

Part Number: BQ24610EVM

Hi Team,

We have received an inquiry from our customer as follows.

So here is what happened to BQ24610EVM. I changed the resistor R25
to 665kOhm so I can get a 16V output for charging a 14.8V battery. I
gave Vin a 19V input, and I did observed Vbat is 15.95V. However, after
I connected the battery to Vbat, I observed there is no current going in
to my battery. I measured it by connected a current meter in series
with battery and BQ24610EVM. I know the battery I used is not fully
charged, and I have tested with some other battery charger that if the
battery is charging, then there should be current flowing into the
battery. I want to know why your BQ24610EVM is not charging the
battery. 

He used the default settings of the jumpers on the board.

Thank you for your support

Regards,

Danilo

  • Dear Danilo,

    Is the jumper JP5 off? If it is, then charge is not enabled. The CE pin is active high and will be pulled low without populating this jumper. Please populate JP5.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.

  • Hi Michael,

    We have received a feedback from the customer. According to him, JP5 jumper is on. Taking JP5 on or off doesn't solve this problem. Is there other settings that he needs to modify on the board?

    Regards,

    Danilo 

  • Dear Danilo,

    Please make sure JP3 is pulled up to VREF. Also please check your TS voltage, you need an external thermistor to bias the TS pin in place. You can start with a 10 kOhm resistor.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.

  • Hi Michael,

    According to the customer, 

    JP3 is set at VREF. I checked the schematics of your board BQ24610EVM, there is already an default resistor divider on the board from TS to VREF, that is R4 and R5. TS should be already biased through R4 (9.31k Ohm) and R5 (430k Ohm), with value of 3.32V assuming VREF is 3.3V. Why do we need to use an external resistor to bias TS again.

    I have requested a picture of the board from the customer in case you need it. 

    Regards,

    Danilo

  • Dear Danilo,

    You need to bias the TS pin with an external thermistor. Please see "Section 9.3.18 Temperature Qualification" of the datasheet. If you do not wish to use a thermistor, we recommend a 10k Ohm for testing. If you do not bias the TS pin correctly the part will not charge.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.

  • Hi Michael,

    The customer tried to bias the TS pin but still don't see any charge current flow to the battery.

    Regards,

    Danilo

  • Hi Danilo,

       Do you see a fault condition indicated on the STAT pins? Ammeter has impedance which can affect the converter, so we do not recommend using an ammeter to measure output current. Instead use a current probe or measure differential voltage across RSR sense resistor.

    By biasing TS pin, have them source an external voltage of 1.8V or include a 10k resistor between TS and GND.

    Log measured voltages of TS, VCC, SRN, REGN as well.

  • Hi Kedar,

    According to the customer,

    TS is 1.682V when biased using a 10k ohm resistor to GND (TS is 3.22V when no 10k ohm resistor is connected) , VCC is 19.4V. STAT1 is 2.1V REGN is 6V. I don't see the SRN pin on the board. This pin is not a test point, and too small to be measured on the chipset. ? Please see the attachment for the TS bias using a 10k Ohm resistor.



    What I realized is the output of the battery shut off to almost zero when the battery is connected. I'm not seeing any STAT LED light up.

    Regards,

    Danilo

  • Dear Danilo,

    Can you please explain "the output of the battery shut off to almost zero when the battery is connected?" What is the voltage of the battery before connection?

    Also, what is STAT2 doing before and after?

    Thanks,

    Mike Emanuel

  • Hi Michael,

    Here is the response of the customer,

    The voltage of the battery output is 14V to 15V before connects it to the battery. It fluctuates. As soon as I connects it to the battery, the voltage drops to somewhere near 0V. I feel you have something that shuts the system off when it detects any charge current.

    Regards,

    Danilo

  • Dear Danilo,

    Can you please check the voltage of the battery before you plug it in? Is it able to source a load, in other words is it fully charged or deeply discharged? You may be plugging in an empty battery and will be in precharge which is 0.3 A.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.

  • Hi Mike,

    According to the customer,

    My battery is not fully charged or deeply discharge. May I know for this board, is there a way to modify the charge current?

    Regards,

    Danilo

  • Dear Danilo,

    Please report the battery voltage before you plug in the battery. If you are below the LOWV threshold (1.55 V on the FB pin) the precharge current will be applied. You can modify the charge current by adjusting the ISET1 voltage. You can modify the precharge current by adjusting the ISET2 voltage.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.

  • Hi Mike,

    Here is a follow up inquiry of our customer.

    Can you explain in more detail about how to modify the ISET1 voltage and ISET2 voltage?

    Regards,

    Danilo

  • Dear Danilo,

    You can modify R11 and R12 to change ISET1 and R15 and R16 to change ISET2. Please see Section 9.3.2 Battery Current Regulation and Section 9.3.4 Precharge for the equations to set charge and pre charge current, respectively.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.

  • Hi Michael,

    We have received this feedback from our customer.

    I double checked the ISET1 setting. According to the default resistor value, Voltage at ISET1 should be 0.6. By using your equation provided on the datasheet, the board should give me a 3A of charging current. However, I'm only seeing a 0.5A of charging current, which doesn't make sense. I double checked the voltage at ISET1 which is 0.596V. Almost equivalent to 0.6V. The equation I found on your datasheet is ICharge=VISET1 / (20 x RSR), where RSR is 0.01Ohm on your user manual. If this equation is not the right relationship between ISET1 voltage and the charge current, please provide the correct equation between charge current and ISET1.

    Regards,

    Danilo

  • Dear Danilo,

    What is the input voltage, battery voltage, ISET2 voltage, ACSET voltage, input current, and adapter rating for your setup? You could be in precharge, input current regulation, or overloading the adapter.

    Thanks,

    Mike Emanuel

  • Hi Michael,

    Here is the customer's response. 

    I don't think the charger is in precharge mode. Here is all the numbers you were requesting. As you can see all the voltages measured align with the expected voltage calculated from schematics. Based on your schematics, your Voltage at ISET2 should be 0.3V, at ISET1 should be 0.6V, and at ACSET should be 0.807V. Below are the measured value. Our power adapter rating can output 3.43A at 19V.

    a. Battery voltage measured is at 15.41V
    b. Input Voltage is 19V.
    c. I measured the input current at the 19V power source. The input current is only 4.2mA. Very small. Sound very unreasonable.
    d. At ACSET point, the voltage is 0.806V.
    e. Voltage at ISET2 is 0.2998V
    f. Voltage at ISET1 is 0.596V

    Regards,

    Danilo

  • Hi Danilo,

      Can the customer take a scope capture of battery insertion? Capture SRN, PH, Charge current, VCC with a 500ms time scale. Also log measured battery voltage before insertion, and measured SRN voltage after insertion, and monitor the logic of STAT throughout.

  • Hi Kedar,

    Here is the customer's feedback.

    The attached picture is the scope for SRN and PH on 500ms scale. The red line on top is the PH, and the yellow line on the bottom is the SRN.


    a. Battery before insertion is 15.67V
    b. VCC is from 18.61V to 18.63V throughout the experiment.
    c. Charge current fluctuate between 0.50A to 0.55A throughout the experiment.
    d. STAT1 is very stable at 34.4mV throughout.
    e. STAT2 fluctuate between 2.48V to 2.55V throughout the experiment.
    f. SRN is very stable at 16.03 after the battery insertion?

    Regards,

    Danilo

  • Dear Danilo,

    Can you please explain your setup more? In one post you say the input current is 4.2 mA, in another the charge current is 0.50 A. These conditions cannot exist simultaneously.

    Also, I read back and it says you set the output for 16 V for a 14.8 V battery. The output voltage should be the maximum battery voltage. You could be overcharging your battery.

    Your SRN voltage in the last post suggests you are in Constant Voltage or Taper mode. What happens if you discharge the battery to 12 V separately and then reattach to the charger?

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answers your question.

  • Hi Mike,

    According to the customer,

    I had the same setup for the two measurement. I'm not sure why sometimes I can only get 4.2mA for the current, but other times I can get 0.5A charge current. There is no setup different. You are correct, they don't exist simultaneously. When I got 4.2mA current, I sometimes have to power cycle the system multiple times to be able to get 0.5A charge current. But there is no setup change.

    To my understanding, the charge voltage should always be higher than the battery voltage in order to make the battery fully charged. My fully charge battery sometimes can reach almost to 16V. That's why I selected 16V to be the charge voltage.

    What do you mean for constant mode vs. taper mode for SRN? Can you elaborate more? My observation is constant voltage. I don't see any fluctuation on SRN voltage.

    Also, can you please tell me for 2.5V on STAT2, do you consider it to be High or Low?

    Regards,

    Danilo

  • Dear Danilo,

    If your SRN voltage is 16 V and you set the output voltage for 16 V your battery is either fully charged or in the constant voltage mode (also known as the taper mode). This means that the charge current will slowly be lowered until the termination current is met and then charge will stop. Depending on the state of the battery upon adapter plug in, you may or may not trigger the recharge threshold. This means the battery may or may not start charging because it is already fully charged.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answers your question.

  • Hi Mike,

    Another follow up inquiry of our customer,

    Also, I would want to know the equation of the charge current for the taper mode. I have another question regarding to the STAT1 and STAT2. Will those two status voltage means anything when the charger is set to taper mode?

    Regards,

    Danilo

  • Please start a new thread to ask this question. Each thread is intended for one major question.

    Thanks,

    Mike Emanuel