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BQ24715: Several question of this part

October 25, 2018, 5:43 am
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Part Number:BQ24715

Dear Expert

My customer is China NB ODM company. For now there is a MP project have some bettery quality problem and they measurement voltage and ask some question.

The battery is 2S 8.8V. And VCC voltage connect to VBUS and VBAT both use two diode( It means even only connect battery, REGN have power and register would not reset )

The problem is that when plug in AC power, we can measure 9V around VSYS voltage. It seems VSYS MAX been set to 9.008V as default value.

I want to ask :

1. If IC VCC always have power supply, how is the condition for Max Charge Voltage Register ( 0x15H ) reset ?

2. And another, how is the charge current regisiter reset condition? We saw the 0x14H register can write value when IC only have battery power to VCC.

3. As above, if VCC always have power, how is the condition to judge charge enable and charge disable? is it judge by ACOK =1 and reset 0x14H to 0x0000?

4. So if VCC always have power, does it mean there will not happen POR condition?

Thank you for reply! 

 BR

Bruce

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TPS54560: Too much switching noise

October 25, 2018, 6:20 am
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Part Number:TPS54560

I use TPS54560 for powering board PC. After assembling and testing I found huge switching noise on outputt under load and without it.

At first start, I measured around 350mV peak-to-peak switching noise. After that, I put an additional 47uF ceramic cap and noise fall to 180-200 mVpp.

Is it possible to achieve around 100 mVpp noise value?

Maybe I made some mistake with pcb tracing?

I use switching freq 1Mhz and 5.4V output config.

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EV2400: 1949558

October 25, 2018, 6:28 am
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Part Number:EV2400

PO number:1949558 EV2400 ,there is a promblem like this.not  It can't update .We bought a new one on estore. It's ok, We suspect that this product has its own hardware problems.Help me!

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TPS650830: Mistakes in data sheet description?

October 25, 2018, 6:32 am
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Part Number:TPS650830

Hi Team,

In the TPS650830 data sheet, there are parts that seem to be wrong.

In the equation that determines the constant of overcurrent protection of equation (3) in P.131

Is not "x1.3" necessary?, Or "IOUTMAX" instead of "IOCL"?

Reason: I think that x1.3 is 130% of "set IOCL to 130% of IOUTMAX" listed above equation (3).

However, Eq. (3) contains the IOCL, plus x1.3 is done there.

130% of IOUTMAX can be understood as IOCL.

So, if you use IOCL in equation (3), x1.3 is unnecessary, and if you use x1.3, I think that it is not IOCL but IOUTMAX.

Best Regards,

Kenji

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How can device(bq40z50-r1)enter shutdown mode?，and also how to exit shutdown mode ? Thanks!

October 25, 2018, 7:21 am
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How can device(bq40z50-r1)enter shutdown mode?，and also  how to exit shutdown mode ? 

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LM25117: Fet turn on

October 25, 2018, 7:31 am
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Part Number:LM25117

I am using the LM25117 to produce a 10A 12V converter and while most of this seems OK, I get some switching that is not 'regular'.  If I set the converter to run at 200kHz, it runs in at 100kHz with times when it tries to turn on after 5us but it then immediately turns off.  I have tried changing the Rt to run at a higher frequency but again it seems to run at half frequency with a turn on for a very short time at the correct point.

The picture attached shows this.  I think the pulse by pulse current limit is turning the FET off but I am not certain why the frequency seems to be wrong

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TPS59620: /

October 25, 2018, 7:54 am
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Part Number:TPS59620

Dear Sirs, good afternoon!

We got the item 5962R1022101VSC with country of origin Thailand. Could you confirm us that it is legal and that TI has factory in Thailand? I could attach photo if you need.

Would you be so kind to send me link of live chat? I'm not able to find it.

We are looking forward to your answer so much.

SIncerely,

Olesya

Sovtest

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BQ2980: if this device suitable for 1-cell primary battery protection circuit

October 25, 2018, 8:07 am
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Part Number:BQ2980

Hello team,

I would like to know if this device is recommended for single (1-cell) Primary (unchangeable) battery protection circuit (Li) that can provide Under voltage, and Overcurrent?

the requirements are very low power consumption and small form factor, Thanks in advance.

Best regards,

Shai  

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LP5569: LP5569 breathing effect, independent LED mapping

October 25, 2018, 8:08 am
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Part Number:LP5569

Hi all,

I am programming an application with the LP5569 for a future consumer product.

I have successfully managed to create effects with the Windows UI software, extract the contents of the RAM, download them to RAM memory and execute them. In particular, I have 2 RGB LEDs and 3 white LEDs on our board. There is a very simple breathing effect that I would like to use and activate on those 5 LEDs independently. I mean activating the breathing only on LED1, then only on LED2 and so forth.

When I use the mapping LED registers (ENGINE1_MAPPING1, ENGNE1_MAPPING2, etc.) , which I believe associate LEDs to the different Engines, nothing seems to change.  The only LEDs that have the effect are the ones selected on the Windows UI program.

Am I missing something here? Are the LED mappings to the engines tied up when the program gets created? But if that is the case, what is the purpose of the LED mapping registers?

Thank you in advance for your help.

David

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LMZ10504: Compensation Network changes in data sheet revisions

October 25, 2018, 8:15 am
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Part Number:LMZ10504

The more recent datasheet (2017)  have the following values:

The data sheet from 2013 - SNVS610L –DECEMBER 2009–REVISED APRIL 2013 has the following compensation values:

For the 5th and 7th lines there are changes in the Rcomp and Ccomp values.

Were there stability issues with the old values? Can you provide some history with stability and the effects?

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TLC5971: TLC5971 for local dimming question

October 25, 2018, 8:23 am
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Part Number:TLC5971

Reference below picture,

MCU can control each bit action through I2C Interface ?

Like: N_OUTR0 ON (N+1_OUTR0 OFF) or N+1_OUTB3 ON (N_OUTB3 OFF)

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LMR33620: package outline

October 25, 2018, 8:28 am
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Part Number:LMR33620

Hi-

The package information for the SO8-powerpad version of the LMR33620 is not in the data sheet. Could you please provide this to us?

Thanks and Best Regards,

-Tim Starr on behalf of JM@ZM

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TPS51604: Bootstrap capacitor discharges and is unable to charge when put into DCM mode and the DRVL and DRVH pins are inactive for a period of time

October 25, 2018, 8:30 am
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Part Number:TPS51604

I have customer trying to resolve an issue regarding the TPS51604 Synchronous Buck FET Driver. The part is currently in use on our 10-Channel Charger and we have run into a problem where the bootstrap capacitor discharges and is unable to charge when put into DCM mode and the DRVL and DRVH pins are inactive for a period of time. The PWM and SKIP signals are provided by a microcontroller and upon startup are put into a low state.

 

We thought that making the SKIP pin high and the PWM pin low for a short duration would briefly turn on the low side mosfet and allow the bootstrap capacitor to charge to VDD but that’s not what happens because the low side mosfet never turns on. The part isn’t behaving according to the truth table and I’m wondering if it has anything to do with the fact that the load is a battery and the SW pin is held at a potential equal to the battery voltage.

I researched a similar ticket on the forum (e2e.ti.com/.../1992849) , however our application is a bit different because the load connected to the output is a battery, so placing a pull-down resistor on the SW pin will not pull the voltage down low enough for the bootstrap capacitor to charge (the SW pin sits at approximately 13 volts when PWM is not present). I have a solution that will allow the bootstrap capacitor to charge even in the presence of a battery but it would require a complete hardware redesign and the addition of many more components. If there was some way we could get the low side mosfet to turn on briefly through some combination of PWM and SKIP signals then I believe it would work.

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LM25066I: What is the accuracy of current sense when VIN-SENSE=1mV and 46mV?

October 25, 2018, 8:41 am
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Part Number:LM25066I

Hi Team,

If the VIN-SENSE=1mV and 46mV,

Could you let me know the current sense accuracy? How to calculate it?

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UCC28950: How to design a CC and voltage limit circuit ?

October 25, 2018, 9:07 am
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Part Number:UCC28950

Hi Team

 we want to use UCC28950 to design a circuit for charging  Li battery pack, the total output power is about 2KW.

 The circuit is in CC mode and full power output when the battery pack voltage is low, and it is into voltage limit mode with low current output as the battery pack increase a threshold value.

Can you give a referance schematic or block diagram ?

thanks

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LMZM23601: Internal Resistance Values for LMZM23601V3SIL

October 25, 2018, 9:18 am
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Part Number:LMZM23601

Hello,

I would like to use the LMZM23601 package to convert from 24V - 12V; However, currently only the "non-adjustable" LMZM23601V3SILR is in stock. I would prefer not to wait until the adjustable version is back in stock so I would like to force the 3.3V version to go to 12V instead. I believe this possible by adding a resistor divider from the output to the FB pin, but I need to know the internal resistance values to account for them in the external resistor divider values. 

I couldn't find this information in the datasheet, do you have it available? 

Thanks,

Kyle Goodrick

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TPS28225: Looking for help with SLUU271 - MathCAD Efficiency and Power Losses Calculation of Synchronous Buck Converter

October 25, 2018, 9:26 am
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Part Number:TPS28225

I thought I had found the paper "what MOSFET Driver Can Do to Boost the Performance of VRM Design", but I was wrong. It was only an abstract. I am still looking for this paper. 

Thanks,

Chuck Samposn

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TPS7H1101-SP: TPS7H1101-SP output lower than expected

October 25, 2018, 9:46 am
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Part Number:TPS7H1101-SP

Hello, I am using the radhard  version of TPS7H1101-SP and the output is lower than expected on multiple boards using similar circuits.

With Vin=5.25V, Rtop=51.1k, Rbottom=11.5k, I expect the output voltage to be 3.3V per equation 3 on the commercial datasheet.  However, I am seeing 3.188V.

I have additional settings on the LDO which I meet per the datasheet.

Thanks,

Earl

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BQ25505: Expected output

October 25, 2018, 10:02 am
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Part Number:BQ25505

what output can I expect from a constant 0.8v and 1.2mA input?

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LP5569: LED's unsychronized after short period of time

October 25, 2018, 10:22 am
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Part Number:LP5569

Hello,

We have a PCB based on your older LP5569 evaluation board.  (4 LP5569 drivers connected to 12 RGB LED chips).  Instead of the microcontroller we are using an FT232HL USB to I2C IC connected to a computer.   We are trying to work out the programming but have noticed the following behavior:

The flashing and breathing patterns use the exact same program code on each chip. I can load each chip individually, and then set the engines to free run mode simultaneously using the broadcast slave address of 0x40 to which all chips respond. But, although I can trigger the execution on all chips simultaneously, and that they visually appear to ramp up at the same rate with visual fidelity, initially, I’m observing that the ramp down times begin to drift across the chips over time and become unsynchronized rather quickly. I’ve read the datasheets for multiple TI LED drivers and, while some have more detail than others, there is no mention of non-deterministic ramp down behavior.

 

The programming/execution steps:

 

    1. Addressing each chip individually (0x32…0x35):
      1. set engine registers to SRAM programming mode
      1. download same program code
    1. Addressing all chips using broadcast address (0x40):
      1. set all engines to free run mode simultaneously to begin program execution

Please let me know if something seems amiss.

Kind regards,

Jack

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