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TPS65279: Operation at low Vin - Vout differential

March 12, 2019, 11:10 pm
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Part Number:TPS65279

Hello,

I am considering this part for a 6V to 5V conversion at 1.6MHz. This results in an ON time of 521ns, and an OFF time of 104ns.

  1. How can I verify the voltage droop of the bootstrap capacitor during this ON time?
  2. Will it get fully charged in that OFF time?

It seem like the datasheet would need to spec the gate charge of the internal FETs for me to answer #1.

For #2, since the LDO is limited to 200mA, over the course of 100ns it can only charge a .1uF cap up by 200mV.

Is it possible for me to figure this out with the datasheet alone?

Thank you,
Ryan B.

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LM2576: LM2576 does not work like LM2576

March 12, 2019, 11:22 pm
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Part Number:LM2576

Hello everbody,

I have a problem about LM2576.I have a power stage design but there is a problem at LM2576.First of all LM2576 is a buck converter so this buck converter is a SMPS and all SMPS converts POWER.

 However it (LM2576) does not convert power.It is working like lineer regulator.

Output voltage of buck converter's is 5 volt. And maximum output current is 3 A . When I  selected about 1,5 ohm resistor, output current was 3A but the problem is arising in this point.In this point,I have observed,input current was about 2,8 A.Input voltage was 8 volt.

If input voltage increase above 8 volt, lm2576 is shutting down itself.

I want to explain numerical value.For example if input voltage is 8 volt and output current is 3A,input current was about 2.8A but lm2576 worked about 10 min.İf input voltage above 8 volt and if output current higher than 1 A,LM2576 was shutdown suddenly.

Sorry for my english.My english is not very good but ı tried to explain my problem.

This is my circuit.

Input capacitor value = 470 uf and 50 volt

Output catch diode value =  60 volt , 2A

Output inductor value = 1uH , saturation 1.4 Amper , Max amper is 3A.

Output capacitor value = 470 uf and 25 volt

I am connecting my load to 5VP output.

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BQ4050: Coulomb Counter

March 12, 2019, 11:27 pm
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Part Number:BQ4050

Hi,

I Dont understand from the datasheet what are the currents that i can measure with this component, for the coulomb counter.

I have:

- 3 cells connected in series. 

- Capacity of 1100mAh.

- Charging current - 100mA

- Discharging current - 100uA (Its not a mistake).

As written in the datasheet the input voltage range is +-100mV.

Can i use 1Ohm resistor, so for 100mA the voltage would be 100mV, and for 100uA the voltage would be 100uV. 

In such case, would the guage register be able the measure 1100mA (2^16*Qlsb=1100mAh)?

What would be the error, and where is written in the datasheet?

Best regards,

Arkadi

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BQ77915: Guidance on BMS circuit

March 12, 2019, 11:34 pm
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Part Number:BQ77915

In continuation to the discussion in https://e2e.ti.com/support/power-management/f/196/t/779439?BQ77915-BMS-for-2-4-Prismatic-Cell, we have also come across a solution (which I am attaching here)

BMS Specification-HLT-715C.pdf

Can you please guide us to understand what kind of purpose this circuit is achieving. Will it be able to
1. Measure Voltage of Cell
2. Measure Current
3. Measure Temperature
4. Calculate SOC and SOH
5. Protect for Over Voltage, Under Voltage, Over Charge Current, Over Discharge

Thanks a lot for your help.

Regards,

Rahul

What is this achieving. 

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TPS59641: /CSKIP and /GSKIP terminal of TPS59461

March 12, 2019, 11:44 pm
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Part Number:TPS59641

Hi

Please let me ask you about TPS59461.
If /CSKIP or /GSKIP pin is left OPEN, what kind of behavior of the IC? Is it ok to leave OPEN these pins?  

Best regards,
Yokota

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BQ25882: About Masked Flag register

March 12, 2019, 11:44 pm
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Part Number:BQ25882

Hi tiers.

I set REG13 Register (Charger Mask 2 Register) as below.

Reg[0x13] = 0x87.

So, PG_MASK (power good INT Mask) is masked.

But When power source is inserted, PG_FLAG (power good INT flag) is still 1 (detected) as below.

Reg[0x10] = 0x82. (After read, set by 0)

Is this right operation?

Does the INT Mask Register relate only to the HW INT output pulse and not to the Flag Register?

Please let me know ASAP.

Thanks.

 

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UCC28070: UCC28070 how to measure voltage loop bode plot

March 12, 2019, 11:45 pm
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Part Number:UCC28070

Hi team,

My customer is using UCC28070 in their design and want to measure the voltage loop bode plot, but their frequency analyzer (FRA5087) can only support inputs upto 250Vrms. 

Is there anyway to measure the HV voltage loop like adding a buffer or amplifier?

Many thanks.

Best Regards,

Wei-Hao

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TPS53626: TPS53626RSMR

March 13, 2019, 12:11 am
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Part Number:TPS53626

Hi,

I want to get the full data sheet for the IC (part number: TPS53626RSMR) which we are planning to use in the solar charger application.

Our application requirement 

V_input = 0.58 V,    I_input = 0.8 A,    V_output = 5 V,  I_output = 50 mA to 100 mA.

Is this IC suitable for our application?

Regards,

John

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TPS61180: In case of OVER-CURRENT condition

March 13, 2019, 12:45 am
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Part Number:TPS61180

Hi all

Would you mind if we ask TPS61180?

There are descriptions on the datasheet as follows;
"The PWM switch turns off when the inductor current reaches this current threshold."
"Under severe over-load and/or short circuit conditions, the VO pin can be pulled below the input (V BAT pin).
Under this condition, the current can follow directly from input to output through the inductor and Schottky diode.
Turning off the PWM switch alone does not limit current anymore.
In this case, the TPS61180/1/2 ICs detect the output voltage is 1V (short circuit detection threshold) below the input voltage,
turns off the isolation FET, and shuts down the IC.
The IC restarts after input power-on reset (V BAT POR) or EN pin logic toggling."
->In case of Over current condition, does it require to insert Fault protection FET at Fault pin for shuts down?
  Without FET at Fault , it is impossible to shuts down the device, right?

Kind regards,

Hirotaka Matsumoto

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BQ27542-G1: BQ27542-G1 design capacity

March 13, 2019, 1:05 am
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Part Number:BQ27542-G1

What will  be occurred when the design capacity is exceeded 14.5AH?

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LM5069: Response time during OV & UV event

March 13, 2019, 1:11 am
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Part Number:LM5069

1. We wanna to know what's the response time to turn-off the switch during OV and UV event with LM5069-1 device?

2. When OVP or UVP threshold is reached, can the voltage on the timer pin be charged up?

Thanks.

Regards,

Brian

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BQ40Z50: battery need to be shutdown by itself on 40% during discharging

March 13, 2019, 1:19 am
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Part Number:BQ40Z50

Hi Team

Could you please help my customer questions below, thanks!

1.May I have a auto shutdown while discharge battery to 40% capacity? Is it possible to add this feature on BQ40Z5x series?

2.Assume to change FW to satisfy customer request, please let us know what quantity should customer buy?

please kindly help comment , thank you

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TPS55010: Is adjusted Output Voltage "Voltage at no load"? or ""vout at load ?

March 13, 2019, 1:24 am
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Part Number:TPS55010

Hi, Team.

i've been asked by Customer as below.

in datasheet, it shows Vout equation , is it "at no load" or "with some load"?

the reason why customer asked me is...

basically Vout would be decreased from no load to light load.

customer uses LDO which has limitation Vdrop , if the voltage in its datasheet mentioned, customer just places some load as "pre load" to be stable.

and , is there any equation to know the voltage at no load and some load from equation ?

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LM5069: Short circuit before power up

March 13, 2019, 1:32 am
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Part Number:LM5069

When we do the measurement of the short circuit before power on, we find the device cannot be latched off with LM5069MMX-1. is this normal behavior? any workaround to latch off?

When doing short circuit after power on, the device can be latched off the FET. It's ok as expected behavior. 

Device: LM5069MMX-1 (Latch type)

 Application: Motor Drive

CH1: Input current

CH2: Timer pin voltage

CH3: Gate pin voltage

CH4: Input voltage

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WEBENCH® Tools/UC1845: UC1845

March 13, 2019, 1:40 am
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Part Number:UC1845

Tool/software: WEBENCH® Design Tools

Hello,

       I need to design an isolated, variable output power supply. Input voltage is 15 to 53VDC, the output

voltage is 2V to 50V, the output current is up to 12A. (Maximum wattage should be 50 W, my current requirement is 5V/5A or 28V/2A) for this, I want a variable power supply)

PWM IC is http://www.ti.com/sitesearch/docs/universalsearch.tsp?searchTerm=UC1845#q=UC1845&t=everything&linkId=1 

I am confused with the transformer selection with this design 

Can anyone help me with the selection of transformer for this design

and also let me know whether I choose the right PWM IC for this design or not?

Where I can order it? Thank you very much. in advance

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BQ20Z655-R1: Regarding BQ20z655-R1 and BQ34z950 cost diffrence

March 13, 2019, 1:44 am
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Part Number:BQ20Z655-R1

Hello , 

I am using Gas Gauging IC BQ34Z950  but it is costly, Comparatively I also find BQ20Z655-R1 , It is in low cost as compare to BQ34Z950 and specification of both IC"s are same and Pin to Pin functions are also same then why this cost difference. Any other functionality is less in case of BQ20Z655-R1 than BQ34Z950 . For Selection Criteria we need this help.

 

Regards

Chaitanya Kulkarni
R&D Engineer
 
Electronica Machatronics System,
Unit No. 37 & 44,
Electronics Industrial Estate,
Pune-Satara road, 
Near Swargate, 
Pune-411009
 
Electronica Mechatronic Systems (India) Pvt Ltd
 
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TPS63001: VSON 10 Footprint

March 13, 2019, 1:45 am
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Part Number:TPS63001

Dear All,

I'm looking for PCB footpint of TPS63001 device (DRC Package 10-Pin VSON), but I can't find it on TI website.

Anyone can suggest me where I can find it?

In general, is there a document (or a link) which shows pcb footprint for each TI package?

Thanks very much in advance

Regards

Stefano

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UCC21520: differences bwtween UCC21520 and UCC21521

March 13, 2019, 1:47 am
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Part Number:UCC21520

Hi

I have a question about UCC21520 and UCC21521. What is difference between UCC21520 and UCC21521? Is that only differences Pin#5?

I know the pin function of Pin#5 is different. However I do not understand why there is two device UCC21520 and UCC21521.

I would like to know the benefit of each device.

Best Regards,

Koji Hamamoto

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TPS61046: How to consider peak output load current capability

March 13, 2019, 1:49 am
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Part Number:TPS61046

Hello,

I'd like to know how to consider peak output load current capability of TPS61046.
For example, is it enough to load 0.2A continuously at Vin=5V, Vout=10V with considering worst case variation?
I'd also like to know how TPS61046 limits the peak current, the inductor selection also affect the load capability?

Thanks in advance.
Sawamoto

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TPSM84205: TPSM84205 adjusting the output voltage

March 13, 2019, 1:58 am
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Part Number:TPSM84205

Hi all,

I need a DCDC like the TPSM84205 or the TPSM84203, because it follows the TO-220 standard pinout, but I would need to vary the ouput voltage to 3.8-4V. Would it be possible to replace one or both of the feedback resistors to achieve this? When you buy the module, the components are covered with some protection glue or I can have access to them? For most of the DCDC converters the feedback resistors select the output voltage and with such a small variation maybe it does not affect the rest of the module.

Thank you very much for your help in advance

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