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BQ24650: Issue with charging where it is on and then fault repeating over and over again and very low pre-charge current.

May 6, 2019, 6:15 pm
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Part Number:BQ24650

Hello Support Team,

I am using the BQ24650 to charge two Li-Ion batteries in series. I have a 20V input and a 8.35V output. When I attach the battery pack (7.9V total) the STAT1 LED turns on indicating charge in progress and then immediately turns off indicating fault. When the LED is on it pulls 6-9mA from the attached power supply. This keeps repeating until I remove the battery pack. In another scenario when I attach a battery pack that is heavily discharged (< 7V) the output voltage is still correct however the current draw is incorrect. It pulls 40mA instead of the 200mA precharge current as designed. I have taken various key measurements that I have attached below to help with diagnosis as well as my schematic of the system. The intended design is for a 17.8V MPPSET with an 8.4V & 2A output.

Any help is much appreciated.

Thanks

Also, one thing to note, the batteries are powering a system at the same time that is not indicated in the schematics.

Measurments No LoadMeasurements W/Battery Not ChargingMeasurements W/Battery Charging
VIN = 20.1VVIN = 20.1VVIN = 20.1
VOUT = 8.35VVOUT =8.05VVOUT =8.2V
VREF = 3.3VVREF = 3.295VVREF = 3.295V
REGN = 5.98VREGN = 5.967V REGN = 5.99V
MPPSET = 1.348VMPPSET = 1.33VMPPSET = 1.31V
TS = 2.03VTS =  2.039VTS = 2.039
VFB = 2.1VVFB = 2.00VVFB = 2.03V-2.09V


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LM3488: Output FET permanently on

May 6, 2019, 6:18 pm
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Part Number:LM3488

I have the same problem as per the linked question. The LM3488 runs for about 3mS when enabled, then switches the FET (Q1) on at 100%.

The connections and part values are as per the diagram, with the correction on R21 to VIN implemented.

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TPS5420: Aging variation of reference voltage

May 6, 2019, 6:24 pm
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Part Number:TPS5420

Hi,

Is reference voltage affected by aging?

If yes, how much does it vary?

Best Regards,

Kuramochi

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LM2734: Tolerance

May 6, 2019, 6:41 pm
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Part Number:LM2734

Hi TI Team,

For the LM2734 Vfb voltage, as you can see, the Vfb reference is from 0.784V to 0.816V If Tj from -40degC to 125degC.  I believe that this tolerance (0.784V ~0.816V) includes initial tolerance and  temperature variation.

For a specific part, for example, if the Vfb is 0.801V at Tj=25degC, what Vfb would be if Tj=-40degC and Tj=125degC ?   Can we refer to the chart shown in Table.2 for Vfb temperature variation? 

Table.2  shows that Vfb changes only 4mV (0.802-0.798V=4mV) variation if Vfb temperature changes from -40degC to 125degC?

The reason we asked this question is that  the initial tolerance (normally in 25degC) can usually be eliminated by calibration, but the for the temperature variation, it can not be calibrated. So we need to know the tolerance caused by the temperature variation.

 

Table.1  LM2734 tolerance

Table.2  Vfb variation vs temperature

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Li-ion Battery AC impedance measurement

May 6, 2019, 6:43 pm
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Hi Ti Guys :

here is the question which is about "Li-ion Battery AC impedance measurement" ;

and just to discuss with you that will any information like as environment set-up / tools / method to reference.

thank you.

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BQ35100: FW update

May 6, 2019, 6:56 pm
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Part Number:BQ35100

Hi Team,

There are some FW update questions. please kindly help.

  1. Do we need input default FW in BQ35100 after mounting on board?
  2. Could we Calibration the non-FW board firstly, and then burn the Calibration FW into BQ35100 after?
  3. If the default FW is need, now we use BQ studio and EV2400 to burn the FW. Any other way to burn the FW?

Thanks

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UC2845A: How much temperature can UC2845A Junction be withstanded ?

May 6, 2019, 7:14 pm
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LM5160-Q1: LM5160-Q1 Questions about how to connect the LM5160-Q1 Flybuck board diagram?

May 6, 2019, 7:19 pm
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Part Number:LM5160-Q1

Dear support member,

My customer used LM5161-Q1.

I have a question.


（Situation)
My customer want to measure the phase margin and gain margin to verify the feedback stability of the power supply circuit.

We are considering using NF FRA 5097 for these measurements.


(Question)
When measuring phase margin and gain margin using this measuring instrument,
Could you teach how to connect this measuring instrument to the circuit diagram below?


Best regard
Bob Lee.

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TPS2549: Charging port controller DCP Dual connection not charging my device

May 6, 2019, 7:37 pm
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Part Number:TPS2549

Hello, I'm working on a basic power-bank device, where I use TPS2549 charging port controller with the same connection like the one in the example, my schematic is shown below: 

I've implemented the exact same schematic on a PCB, but when I tried to connect any Samsung mobile phone, the phone keeps showing like if someone is connecting and disconnecting the charger multiple times. When I measured the current output using a multi-meter, it's like 3 mA only.

I've tried to connect a Huawei mobile device and it was charging with only 100 mA, and it wasn't stable.

Knowing that the power source (Vout_boost) is a 5V 2A Input. 

I've connected the same schematic on a separate PCB to test it (i thought maybe it's an issue from the other circuits), but the same result is happening.

I've tried to add an output capacitor as well, which somehow stabilized the 100mA for my huawei device. but still it's too low, I want a charging current of 1 Ampere or more.

I've also tried connecting multiple different mobile devices, and I've tried to use different current limit resistor values but without any hope, I can't get more than 100 to 130 mA for my devices. and my Samsung phones are not charging at all.

Can you guide me through this issue. Correct me if I'm doing something wrong.

Regards,

Hazem.

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TLC6C5724-Q1: How to use LATCH signal correctly

May 6, 2019, 7:41 pm
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Part Number:TLC6C5724-Q1

According to Spec. P.11 & P12, it show the waveform of "GS data write" & "FC/BC/DC write".

When GS data write, the LATCH is default low, and will issue a rising pulse (L->H->L) after 288 bits GS data.

When FC/BC/DC write, the LATCH is default high, and will issue a falling pulse (H->L->H) after 288 bits command & FC/BC/DC data.

If i want to set FC/BC.DC data after GS data update, the LATCH should go High before issue FC/BC/DC data.

But it will lead to a rising edge of LATCH which may cause latch unknown data.

what's the correct waveform of that scenario? 

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LM5066: LM5066 Reverse Current Reading Issue

May 6, 2019, 8:12 pm
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Part Number:LM5066

Hi,

Can LM5066 read reverse current and through I2C send data to MCU? 

If it can't, is any method to read reverse current by adding a external circuit?  

Thanks.

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BQ24617: How to set the termination current below 125mA

May 6, 2019, 8:35 pm
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Part Number:BQ24617

Hi,Sir:

     From the spec of BQ24617 charger, it descripte that the termination current will clamped to be around 125mA

with default 10 mOhm sensing resistor.

If I want to set the termination current below 125mA,

for example,set it to 60mA,

So I should change the sensing resistor from 10 mOhm to 20 mOhm, right?

If not, how to adjust it?

Thanks!

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LM285-2.5: LM285BXMX-2.5/NOPB Vref shifted after aging

May 6, 2019, 9:57 pm
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Part Number: LM285-2.5

Hi,

(Part number : LM285BXMX-2.5/NOPB , Application : DCS card)

My industry customer encountered Vref (reverse breakdown voltage) shifted problem after certain period of usage time.

Customer actually captured Vref value during production for their tuning calculation.

However, the device's Vref is slightly shifted after certain period of using/aging at their end customer.

In this case, 2 pcs of IC were used in one PCB (normally both IC are from same lot and have similar Vref).

The failed IC Vref is measured as 2.484V while the other OK IC is 2.495V. So customer concluded that the Vref of failed IC should be around 2.5V during production time.

Customer understood TI's part has no problem and meet the datasheet specification.

However, they would like to know the stability of the Reverse breakdown voltage(Vref),.

How long does the device needed to age until it becomes stable?

Is there any data of Vref level that TI able to provide before & after aging test?

Or what is the percentage of Vref shifted before and after device aging?

 

Thanks.

Best regards,

Chin

 

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BQ25882: BQ25882 and Battery Balance

May 6, 2019, 10:00 pm
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Part Number:BQ25882

My applications are as follows:

1. Two lithium-ion batteries are used in series to supply equipment similar to a moving camera. They take pictures while walking. There are three three-phase DC brushless motors on the equipment (power supply voltage is about 7V). The function is to adjust the camera to maintain a stable state so as to have a better picture.

2. The static current of the three motors is less than 1A, but there will be transient 3A or so when starting, and the maximum is not more than 5A.

3. Battery charging chips are now planned to choose BQ25882.

My questions are as follows:

1. Do we need to consider battery balancing in our applications?

2. I saw BQ25887, which has the function of battery balance, but it has not been mass produced yet, and it is very large. Can you recommend the appropriate balance circuit to match BQ25882, which is suitable for our application?

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BQ25887: battery balancing

May 6, 2019, 10:14 pm
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Part Number:BQ25887

My applications are as follows:

1. Two lithium-ion batteries are used in series to supply equipment similar to a moving camera. They take pictures while walking. There are three three-phase DC brushless motors on the equipment (power supply voltage is about 7V). The function is to adjust the camera to maintain a stable state so as to have a better picture.

2. The static current of the three motors is less than 1A, but there will be transient 3A or so when starting, and the maximum is not more than 5A.

3. Battery charging chips are now planned to choose BQ25882.

My questions are as follows:

1. Do we need to consider battery balancing in our applications?

2. I saw BQ25887, which has the function of battery balancing, but it has not been mass produced yet, and it is very large. Can you recommend the appropriate balancing circuit to match BQ25882, which is suitable for our application?

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LMR14050: To pass conducted emission test

May 6, 2019, 10:19 pm
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Part Number:LMR14050

I am using LMR14050SDDAR  switching regulator which is designed for 28V input and 5V output. I have set switching frequency to 800khz. But its failing conducted emission test as ripples are very high in the harmonics of 800khz. Kindly let me to how to reduce the ripple.

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LMR14050: Conducted Emission Test Fail

May 6, 2019, 10:36 pm
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Part Number:LMR14050

Hello

I am using LMR14050SDDAR switching regulator in my design to obtain output of 5V from 28V input. I have set the switching frequency to 800khz. Its failing conducted emission test. High ripples are obtained at 800khz and its harmonics. Kindly let me know how to reduce this so that test gets passed.

Regards

Nidhi P Shetty

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LP87564-Q1: Individual PGOOD signal

May 6, 2019, 10:53 pm
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Part Number:LP87564-Q1

Hello,

My customer would like to know if there is a way to configure the ENx pins as individual PGOOD for BUCKx, for example, configure EN1 as a GPIO output and report PGOOD status of BUCK1 directly?  

They want to use these pins for power sequence.  Since there are 4 bucks in LP87564, they want to ramp up BUCK0 and BUCK1 first, then use PGOOD of BUCK1 to enable an external regulator.  When the external regulator is up, continue BUCK3 and BUCK4 ramp.

They prefer this configuration be loaded at bootup; after that, no software involvement is needed.

I did not see a way to configure ENx pins as individual PGOOD signals in the datasheet, but I believe an individual PGOOD could be output from the PGOOD pin or nINT pin with proper masking of PG or Interrupt controls, is that correct?

Thanks,

Alan

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BQ25150EVM: Charger_1_00-bq25150.bqz

May 6, 2019, 10:54 pm
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Part Number:BQ25150EVM

Please be kind enough to email me the "Charger_1_00-bq25150.bqz" file as bqStudio (ver 1.3.86) doesn't have it.

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CHEM ID matching test question

May 6, 2019, 10:58 pm
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Hi !

i will use the GDK and gauge EVM to help my customer build the CHEM ID matching first, the question is my customer project battery design capacity is 240mA, then charge test will need to 1/100C to stop~2.4mA, i found the GDK can not charge the battery to so small value, may i have some suggestion how to use the GDK to finished this test and meet this condition, thanks !

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