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TLC59116F: Datasheet Query

August 2, 2019, 4:30 am
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Part Number: TLC59116F

Hi Team,

We found some discrepancy in datasheet of TLC59116F. 

Datasheet spec mentions, when all LEDs are OFF, Supply current = 13mA 

In the graph @ 6.7 Typical Characteristics shows, for Vcc=5.5V, Icc = 10mA in Figure-1, could you let us know the reason why is the OFF state current more than ON state current.

Figure-2 data is not understandable. It says Icc vs Vcc with all LEDs OFF but graph is Rset vs LED current and the Figure-2 graph looks same as Figure 21.

(Please visit the site to view this file)

Can you please check and confirm the same.

Regards, Shinu Mathew.                                                                  

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BQ40Z80EVM-020: CAD Files

August 2, 2019, 4:33 am
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Part Number: BQ40Z80EVM-020

Hi,

Is there a CAD files of the BQ40Z80EVM-020 to use it as reference for our new design?

Thanks...

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BQ24610: Question about the BQ24610 safety timer function

August 2, 2019, 5:05 am
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Part Number: BQ24610

Hi team,

     My customer would like to use BQ24610 device for charging, but according to the maximum charging current, the charge time would be more than 10 hours, not in the range of 1h~10h. Could we use larger CTTC value (>0.11uF) to set larger charge time? And could you please share the way to disable the function, is there any risk? At present, customer found when achieve safety time, the BQ24610 device would stop charging and flash red light. Thanks a lot!

Best Regards

Zhengquan Lu

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TPS23753A: output voltage is not stable, IC have noise，

August 2, 2019, 5:14 am
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Part Number: TPS23753A

(Please visit the site to view this file)

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TPS62040: Protect

August 2, 2019, 6:10 am
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Part Number: TPS62040

Hi：

Regarding TPS62040, please help to confirm the following questions:
1. What is the mechanism of device short circuit protection?Is there a risk of triggering short circuit protection if the output terminal is too large?
2. After triggering the short circuit protection, will it be automatically relieved when the conditions are met?
3. As mentioned above, is there a maximum limit for the output capacitance?How many if any?
4. Is 1.2a continuous output current?

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TPS3422: looking for similar device such as MAX16150

August 2, 2019, 6:26 am
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Part Number: TPS3422

Hi team,

Could you please advise if TI has a device similar to MAX16150 which has latched output that can serve as a switch to connect the load directly to the power supply,

Thanks in advance

regards.

Shai 

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BQ76920EVM: Dynamic load with energy recuperation

August 2, 2019, 7:34 am
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Part Number: BQ76920EVM

Hi!

I'm looking at the EVM schematic and I'm struggling to define what happens in the circuit when:
- the Battery is sourcing the energy (discharge state) at first, both DSG and CHG FETs are turned on.
- then the load acts as energy source - let's say It's a motor with regenerative braking.
- plus everything can happen in short/long uncontrollable peaks.
Does this smart battery act like a normal battery or some sort of protection kicks in? Can someone explain what happens with the extra energy?

From the notes i see that if DSG current is small enough the DSG fet is turned off, so the current could only flow by the body diode. But then probably CHG FET would be off so battery could not charge,

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LMZ14203H: This design is suspected of having noise, please help to check

August 2, 2019, 7:37 am
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Part Number: LMZ14203H

Hi TI

We are the equipment manufacturer of ATE, developing DPS. At present, we use LMZ14203H as the source of DPS chip, but have noise by customer reponse when performing CMOS image sensor test. It is suspected that it is caused by power source. Please help confirm Is the circuit correct? Thank you!!

The following is the power information:
1. LMZ14203H VIN: 26.4
2. VOUT range from 5V to 23V by digipot adjust, typical: 11.5V

a. We want to know what is the possibility that this circuit will cause power noise?

b. Is it feasible to design the digipot at the RFBT location?

Thank you for your response

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LM5041: Boost + Push-pull cascade

August 2, 2019, 7:56 am
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Part Number: LM5041

Hi Team,

a customer of mine is considering the LM5041 for a new design and has the following question:

I am currently looking at the LM5041 cascaded PWM controller for a  current fed +/- 140V out 20 W power converter.
This uses a buck stage followed by a push-pull transformer stage, all controlled by the LM5041. I like the current fed

approach because it prevents the high current pulses associated with a voltage fed transformer, when generating

high voltage outputs. In the past I have had to use special low-capacitance output windings to prevent serious

transformer heating in a voltage fed approach, so I favor the current fed.

 

However, it seems like a cascaded boost stage followed by a push-pull transformer would reduce the required turns

ratio needed, by making the center tap voltage of the transformer higher.  I seem to recall that T.I. once made such a

controller at one point in time.  Does T.I. make anything that does this or are there problems associated with the boost

approach?

Regards

Mihir

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LM2758: Max torch/flash current

August 2, 2019, 9:12 am
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Part Number: LM2758

Hello SIrs,

For this LED driver , may I have your comment what's max torch/flash current  ?

Can Rset below 10K ohm ? If its OK, why D/S Fig.6 show Rset range start from 10K ohm ?

Many thanks a lot !

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TPS7A16A-Q1: EN slew rate question

August 2, 2019, 9:37 am
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Part Number: TPS7A16A-Q1

In another post, it was stated:

"While rare, TPS7A16-Q1 can experience issues in applications where the EN slew rate is faster than 1.5 V/us (note that our maximum recommended slew rate for EN is 1.5 V/us).  The TPS7A16A-Q1 is less susceptible to the Ven slew rate; however, we still recommend EN slew rates of less than 1.5 V/us."

My questions are:

1. What specific issues or failure occurs with TPS7A16-Q1 when EN slew rate is faster than 1.5 V/ns?  (Latch up, permanent device damage, other)

2. How was the TPS7A16A-Q1 designed to have less susceptibility to fast EN slew rate?

Thanks,

Alan

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TPS565208: Thermal junction calculation

August 2, 2019, 10:09 am
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Part Number: TPS565208

Hi

I was looking at web bench for ic to convert 12V to 5V with 4Amp which I found TPS565208. 

My question is power dissipation and how hot this will get

Base my understanding you calculate junction  temp:  (Vout-Vin)Iout x (1-%Efficiency)  x Ramp= (12-5)*4*  (1-.94)*95C/W = 159.6C

But if you look at the web bench you will see the IC junction temperature 80.4C so which one is correct 

even if look at TPS565208 EVM does this board can handle 3Amp without heating up 

 Link to webbench 

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TPS23861: PSE_N2 output of TPS23861 is abnormal

August 2, 2019, 10:43 am
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Part Number: TPS23861

Hi TI

The PSE_N2 output of TPS23861 is abnormal and will jump between 27V and 45V (the voltage should be 0V after the POE device is required).

We have the following checks:  

1. Output is normal 48V.   

2. CH2_GATE Voltage is 0V           

3. SHUTDWN_N Voltage is 3.2V           

Can you check the reason for the abnormal output of PSE_N2?

Thank you,

Jerry

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UCC256303: Load dump, back EMF

August 2, 2019, 12:03 pm
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Part Number: UCC256303

Load is a motor that returns energy back to the DC output when "braking". Output caps absorb the energy to an acceptable voltage maximum. Bleeder resistors eventually slowly discharge this energy back down to the voltage regulation set point. But a sudden "forward" load can happen before the bleed-down is finished. The power supply must be ready to instantly power this next load pulse.

If the bleed-down takes longer than 200 mSec, I think that the Burst Mode operation of the UCC256x0x will put the controller into a soft start recovery sequence and not be able to respond quickly to the next load pulse. Is my understanding correct? If so, is there a way to disable the Burst Mode from resetting the soft start?

(The upper mosfet bootstrap will be powered by a separate charge pump to keep it ready to go during a long pause between bursts.)

Thanks for all your help!

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TPS650864: TPS650864: Power sequencing order & current requirement

August 2, 2019, 11:35 am
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Part Number: TPS650864

Hi,
Part No.:- TPS6508640, TPS544C25,CSD87381P1, CSD87331Q3D
Evaluation Board:- PMP12004-HE
FPGA:- XCZU9EG-FFVB1156

      i am using Xilinx "XCZU9EG-FFVB1156", for that trying to use "TPS6508640","TPS544C25" and PMP12004-HE
reference design. But reading the TI document getting few confusion. so requested to clarify the below point:-

1. As per Xilinx data sheet "VCCINT" should be powered up before "VCCBRAM", But as per TPS6508640 datasheet "VCCINT" getting
powered up later to "VCCBRAM". if we use the reference design as per TPS6508640, will it create any problem to FPGA while
power on and its functioning ?

2. please refer para 6.3 of "TPS6508640" datasheet saying that "Dashed lines show the option to short VCCINT with
VCCBRAM for cases where their voltages are the same and current < 25 A. In this case, the TPS544C25 device is not
needed and GPO1 should be shorted to CTL4". The suggested FET "CSD87381P1 (in TPS6508640 datasheet" " or "CSD87331Q3D (in PMP12004-HE)", having current rating max 15A.
then how to achieve the current requirement between ">20A and <25A" when "VCCINT" and "VCCBRAM" are shorted together.

3. as per xilinx dataseet (ug583, page no. 34, table no. 1-13), "VCC_PSPLL" power supply should be different then "VCC_PSAUX" power supply. but in "PMP12004-HE", both are
supplied by "BUCK 5". Also as per xilinx dataseet (ds925, page no. 4, table 2) recommanded voltage level for "VCC_PSPLL" is 1.2V while "VCC_PSAUX" is 1.8V, then
why both supply are coupled in "PMP12004-HE"?

4. Can we change the power sequence order in "TPS6508640" via I2C, permanentaly?

Thank You

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BQ25120A: BQ2512x Schematic Review Checklist

August 2, 2019, 1:42 pm
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Part Number: BQ25120A

What are some key considerations when designing a BQ2512x schematic?

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BQ27510: BQStudio Learning cycle not following expected behavior

August 2, 2019, 2:58 pm
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Part Number: BQ27510

Hello,

I'm using BQ Studio for the first time with my 1300mAh single LiPo cell. I've tried to do a learning cycle twice now but to no avail. I'm following the instructions in SLUA902 page 7. My logging file is attached. A couple questions and comments:

1. For each of my two attempts, I did not allow it to relax for >5 hours before the charge cycle. Is this 100% required? My PCM opens at 3.0V, and each time I was worried the PCM would open, hence cutting off power to the fuel gauge. Does it matter if I discharge until the PCM opens? Or should this be avoided? 

2. Do I program a new (guessed) ChemID before the learning cycle? Or just stick with the default? I've updated all the data flash values as appropriate.

3. On my most recent learning cycle Qmax did not update and update status did not change to 01 after 2 hours of relaxation after a full charge. Could this have to do with not giving the battery enough time to relax at full discharge previously? It got probably 1 hour of relaxation, not 5. 

Any advice would be appreciated on how to best get over this hurdle. Thanks. (Please visit the site to view this file)

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TPS2121: Doubts with the configuration to work as a Power mux for Automatic Seamless Switchover with Priority (XREF) whitout an external precision regulator

August 2, 2019, 4:14 pm
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Part Number: TPS2121

Hello.

I am currently working on the development of a device that fulfills a function similar to that of the UPS. The fact is that I have 2 12V power supply and I must have priority over one. I found the TPS2121 chip and it fits perfectly for what I should do. I have reviewed all the available documentation and I have little doubt regarding the configuration in XREF mode.

Since the space of my PCB is limited and thinking of not increasing the cost of BOOM I don't want to add an external 3.3v regulator. I have used the following configuration for my circuit, I place the image below.

I would like to know if the configuration that I have implemented is fine or can present failures when manufacturing the device. On your page I have not found the simulation tool of the TPS2121, I would like to know where I can find it available to perform the simulation.
Is it mandatory that you use an external regulator?
The main POWER SUPPLY is 12V and its minimum voltage in the worst case is 11V.
The secondary source has a voltage of 12V and comes from an AC / DC module which has a variation of + -3%.
In the worst case I have: VPR1 = 2.763V if VIN1 = 11V
VCP2 = 2.81V if VIN2 = 11.7V.

I appreciate any guidance you can give me. Thank you.

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TPS2660: 48V 2A Input did not work as expected

August 2, 2019, 6:32 pm
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Part Number: TPS2660

We tried to apply 48V @2A input to enable TPS26600PWPR according to following schematics, but failed (no outputs) with circuit protection. What's the problem and how to adjust sub circuits design?

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BQ27541-V200: read the device name after unseal

August 2, 2019, 7:01 pm
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Part Number: BQ27541-V200

Hello TI team，

    We did an experiment, first to seal (0020), then unseal(0414 3672, FFFF, FFFF), and then load dfi file, it will automatically seal after loading（FAS flag and SS flag is red）.The result is that the device name cannot be read.Why is an unsealed product automatically sealed when a dfi file is loaded?

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