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BQ25101: Straight to Fast Charge

December 11, 2018, 4:31 pm
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Part Number:BQ25101

Hi Team,

My customer is having an issue where they are not observing the charger in pre-charge, it goes straight to fast charge. They are simulating a battery on the output for this test. They hold the voltage below the pre-fast threshold of 2.5V, but do not observe their expected pre-charge current of 6mA. Instead they observe the fast charge current of 30mA. Any idea why this might be? Below is their schematic.

I have asked for scope shots of this behavior to see if the device is ever in pre-charge before fast charge and/or if the output is oscillating at all to make sure we aren't oscillating around the pre-fast threshold. Even then, you would expect to see a fluctuation in charge current, right?

Thanks,

Joe - FAE

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BQ34Z100-G1: Design Energy

December 11, 2018, 4:38 pm
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Part Number:BQ34Z100-G1

Can you please explain the meaning of DesignEnegy parameter.  Pack or Cell?

I have a battery pack that consist of 24 LION cells.  6x cells in series and 4x cells in parallel.  

The specifications for a single cell is is 3.6V (nominal) and 3300mAh (rated).

The pack specifications are thus:

Nominal voltage = 21.6V (3.6V * 6)

Rated Capacity = 13.2 Ah (3.3Ah *4)

Rated Energy = 285.12 Wh (21.6V * 13.2 Ah)

I have selected the DesignCapacity to be the rated capacity for the pack (13200mAh).  Is this correct?

I expect the DesignEnegy to be set to 285120 mWh but I am limited to the max value of 32767mAh.  Do you have a solution for this?

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BQ35100: Maximum Voltage Divider for VIN

December 11, 2018, 5:30 pm
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Part Number:BQ35100

Hi,

We are using the BQ35100 in our design. We have 2S Lithium Thionyl batteries which make around 7.2V.

As VIN only accepts between 0 and 1V, we must use a voltage divider to reduce the voltage. We would like to minimize the current drawn through the voltage divider as much as possible. This is because our device will spend a lot of time in a low power state.

The BQ35100 will either be used in EOS or Accumulator mode.

My question is. What is the largest resistors that can/should be used with this setup? Also, is the voltage divider needed at all, perhaps there is another way of doing it?

Thanks!

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TPS53353: The VDD of TPS53353 drop to 4.2~4.5V.

December 11, 2018, 5:57 pm
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Part Number:TPS53353

Hi Experts, 

I use TPS53353 to design DDR4 power, 12V to 1.2V, the VDD of TPS53353 comes from ATX PSU standby 5V, the PSU has an abnormal operation, if the system state change to S0, the 5V standby of ATX will drop to 4.2~4.5V, but the min VDD of TPS53353 is 4.5V, so I want know 4.5V is the min design for VDD ? If the VDD is lower than 4.5V, the VREG didn't less than 3.95V(ULVO), TPS53353 should work okay, right ?

Thanks.

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Linux/TPS53681: TPS53681: No output voltage

December 11, 2018, 6:14 pm
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Part Number:TPS53681

Tool/software: Linux

Hello, we are debuging the TPS53681, it's expected to control the A channel  through the PMBus commands to output PWM1/PWM2/PWM3 and through three chip CSD95490Q5MC to get a 0.42V voltage, Now the IIC to read/write registers is all OK, and my configuration like so: the 0X00 register is set to 0X00, the 0X03 register is set to 0X00,the 0x04 register is set to 0x02,the 0x01 register is set to 0x80, the 0x02 register is set to 0x1B, the 0x24 register is set to 0x0029,the 0x2B register is set to 0x001B,the 0x21 register is set to 0x001D, other registers use their default values, but no PWM measured at the TPS53681output endpoint, So now I need to understand the operating flow how to output the expected PWM  by the TPS53681 through sending PMBus commands, or whether there is a corresponding development DEMO code, hope to reply, thank you.

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TLVH431A-Q1: Min Vin to bypass Vin to Vout directly

December 11, 2018, 6:23 pm
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Part Number:TLVH431A-Q1

Hi Team

for reference regulator using shunt regulator as below,

if Vin drops below Vout, I think Vin will be passed to Vout directly without close loop controlled. 

I woul like to know the Min Vin that can make Vin bypassed to Vout directly without close loop controlled.

from the below calculation, if Vin is below 4.25V, TLVH431A will bypass Vin to Vout directly without close loop controlled ?

Min Vin = Vout + Rsup x Iout = 1.8V + 245 ohm x 10mA = 4.25V

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TL431: TL431 Reference Voltage vs Free Air Temperature

December 11, 2018, 6:45 pm
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Part Number:TL431

Hi,

I refer to TL431 datasheet Page 14 Figure 1: Reference Voltage vs Free-Air Temperature under Item 7.14 Typical Characteristics.

This graph only shows general grade tolerance with Vref (max)=2550mV and Vref (min)=2440mV.

Do you have similiar Reference Voltage vs Free-Air Temperature graph for grade A (P/N: TL431AQDVZR) and grade B (P/N: TL431BQDVZR)?

Please kindly advise, thanks.

Best Regards,

Philip

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BQ27541: Setting update issue.

December 11, 2018, 7:00 pm
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Part Number:BQ27541

Hi,

When use the EV2400 to read the Flash of the Gauge IC(BQ27541), and the software is" bq gas gauge evaluation software", we find that the package voltage of the battery from the "DataRAM" column can up to 4410mV (refer to the attatchment log file), but when we read the "DataFlash" column, the "Lifetime Max Pack Voltage" is 4397mV, Please help us to analyse why the max voltage 4410mV is not updated into Dataflash? TKS!

Q2: Where can I find the detail introduce of  of the "Cycle Count"  ?

(Please visit the site to view this file)

(Please visit the site to view this file)

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UCC28180: Package Power Dissipation

December 11, 2018, 7:19 pm
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Part Number:UCC28180

Hi All,

My customer ask me Pd ( Package Power Dissipation ) of UCC28180.

Because their customer required it for Application data for "China energy efficiency index".

Another Maker's PFC IC datasheet shows Power Dissipation at Maximum Ratings

If TI cannot answer Pd, they cannot use UCC28180.

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EMB1428Q: some questions of 1402EVM

December 11, 2018, 7:27 pm
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Part Number:EMB1428Q

Hi，dear ti enginner:

I am debugging the active balance with 1402EVM. And i use my own MCU,not TMS570.

I refer to the TMS570 code to write my own code.And I used the BQ76PL455 ‘ GPIO to communicate with EMB1428 not real spi.

There are some questions,I hope to get your help.:

1.the D4 light is light up and turn off soon,and then repeats the process always. Is this the correct phenomenon by use TMS570 DEMO software?

   I find When GPIO5 is set to low voltage ，the D4 will light up，when the GPIO5 is set to high voltage ，the D4 will turn off. it is opposite of the  schematic named TIDA-00817?

2.The code in function     void EMB_SetCS(int nDev_ID, int CS)

nRead = ReadReg(nDev_ID, 120, &bTemp, 2, 0); // Read GPIO dir register

No.120 register is 1 blen，not 2 blen.

Does this affect the operation of the code?

3.I still can't implement the active balance function. Is there any reference material that can help me solve this problem?

Thanks for you help.

regards.

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TPS62290: The question about the feedback divider network Resistance.

December 11, 2018, 7:30 pm
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Part Number:TPS62290

Hello,

     For about the feedback divider network Resistance. The datasheet of TPS62290 promote R1=360K and R2=180K, But Our customer think that a smaller resistance is more suitable and more Stable and reliable. like under 100kΩ. Because it means stronger driving current for the FB side. Do you think it's necessary or we can still use the recommend Resistance? would you please give your advice for us? thanks.

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LM3630A: Question for datasheet Spec

December 11, 2018, 8:03 pm
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Part Number:LM3630A

Hi

My customer "Netronix Inc" have the question for the LM3630A datasheet spec.

What is the mean for HWEN=VIN, I2C shutdown as below table?

I think that is test condition for Ishdn, right?

 

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BQ4050: Bq4050EVM-561

December 11, 2018, 9:13 pm
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Part Number:BQ4050

We are drop this project just because of Data flash read and write problem and going in loss too.

Thanks for the support.

Regards

Rahul Kumar (VNL)

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BQ4050EVM-561: bq4050

December 11, 2018, 9:14 pm
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Part Number:BQ4050EVM-561

We are drop this project just because of Data flash read and write problem and going in loss too.

Thanks for the support.

Regards

Rahul Kumar (VNL)

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LM3414: lm3414 LED driver initial rush current when load conected

December 11, 2018, 9:27 pm
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Part Number:LM3414

Hello , 

i am using LM3414 for LED string (4 LED in series ) driver . Power supply 18~ 24V . LED VF = 2.82 V/ LED 

please see attached schematics  . when switch B closed (2LED in CIRCUIT  ) , When Switch A is close from open condition , rush ciurrent peak occur which is more than 1.5A .

but when switch B open (4 LED in circuit ) and switch A open to close no much inrush peak occure ( less than 1.5A )

Please help how to reduce that peak above 1.5A ???

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LM5145: Could you please tell me any countermeasure to reduse high side gate ringing on EVM board?

December 11, 2018, 9:28 pm
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Part Number:LM5145

 Hello guys,

 One of my customers is evaluating LM5145 using  LM5145EVM-HD-20A (http://www.tij.co.jp/jp/lit/ug/snvu545a/snvu545a.pdf) for their new products.

 But they can't buy Infineon device dut to their distribution channel. So they replace BSC117N08NS5 for Q1 and BSC037N08NS5 for Q2 on EVM

with TI, CSD19531Q5A for Q1 and CSD19533Q5A for Q2. Also they change the following spec of EVM too.

1. EVM output voltage: 5V -> 12.5V.

2. Output capacitor: 47uF*7 -> 47uF*1.

3. Inductance, L2 , 3.3uF -> 15uF.

4. Switching frequency: 220kHz -> 370kHz

5. Input voltage: 24V

 When they measured effeciency of the EVM, the effeciency is about 90%. They thought it is low effeciency. So they cheched the gate voltage of Q1 and Q2.

As the result, they found Q1, the gate voltage of CSD19531Q5A(High side FET) was ringing dutring about 100ns with 5V swing  .

They think the high side NMOSFET, CSD19531Q5A could not be used with LM5145 because of high speed turn on/off characterstics.

 They wants know whether it is not good to use CSD19531Q5A for high side NMOSFET with LM5145 or not.

 Could you please give us any comment? And if you have any idea, could you please tell us any TI NMOSFET part number for the high side NMOSFET?

 Your reply would be appreciated.

 Best regards,

 Kazuya Nakai.

 

 

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LM5050-1: LM5050 HV Application Circuit Question

December 11, 2018, 10:04 pm
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Part Number:LM5050-1

Hi champs,

My customer is interested in the HV circuit we suggested for VCM>80V, but they are not sure about  the function of Q2. Would you kindly explain this?

Thanks a lot..

Best Regards,

Wei-Hao

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TPS23521: TPS23521 power capability

December 11, 2018, 10:21 pm
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BQ24195: OTG pin high and VBUS_STAT = 01 (USB Host) does not always give 500mA IINLIM

December 11, 2018, 10:38 pm
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Part Number:BQ24195

I am having trouble with the default IINLIM setting of the BQ24195. It seems not always to follow the truth table described in the datasheet (Table 2)

For this test I have D+ and D- tied to GND through 15kohm resistors always. The REG08 always reports back VBUSTAT = 01 (USB Host) - No Problem.

I have OTG pin pulled high to Vsys (via 10kohm resistor with 100nF bypass cap)

When I have no battery connected to the system and simply switch on the external power supply, the current limit gets set sometimes to 100mA, sometimes to 500mA (Confirmed by reading REG00 and looking at my power supply output current)

When I get into this state, I can toggle the OTG pin but there is no change to the current limit. (in spite of the fact that VBUSTAT = 01 (USB Host) always). If I trigger a DPDM again via REG07:DPDM_EN, the current limit will then follow the  OTG status (at the time of triggering the DPDM) subsequently changing the OTG does not seem to change the current limit.

Is the input current limit as set by table 2 determined only at the point of DPDM detection (i.e. power on and register change) or should it follow my OTG pin?

Secondly it seems I may have a race condition here. The OTG I see now is pulled to Vsys with 10k and has a 100nF capacitor, which will give a time constant of only 1ms. Could that be enough to explain this behaviour? I wouldn't think so. Surely the time it takes to get the power good signal and perform DPDM.

If I have a battery connected I do not see this problem. 

When I have a charged battery connected the Vsys will be high before I connect the VBUS so the OTG will be pulled up before the DPDM is triggered - this leads me to believe it is a race condition,.

We dont have a normal use case where no battery is connected but in case of removal inadvertently or in case of dead battery I assume the same problem will occur. In this case with 100mA I cannot assure that the host MCU will have enough current to get out of reset to change the settings.

Thanks

Fred

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5V, 5W isolated power supply requirement with 10 to 20VAc, 45 to 60Hz input

December 11, 2018, 10:59 pm
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Hello,

Need to design AC to DC converter with following specifications.

AC input voltage : 10 to 20VAC, 45 to 60Hz

Output voltage: 5V

Output power = 5 to 10 watts

Isolation = 4KVrms

This power supply has to work only at low voltage mode (10 to 20Vac) and should not function when the ac line is at high power (110 to 230Vac, ) mode.

The AC lines are coming from the inverter which can operate at low and high power mode.

looking for your suggestions to design for the above requirement.

Thanks and regards,

Prabhakara

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