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BQ40Z50: difference between protection flags and XCHG XDSCH flags

September 18, 2019, 6:44 am
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Part Number: BQ40Z50

Hi ,

After editing the data memory in such way that all the "ENABLE PROTECTIONS" are disabled, in addition , non of the hardware protection flags are on, the XDSCH and XCHG flags are set , which means that voltage do not transfered from the pack pin to the batteries and the fets are closed. It contradicts the fact that i disabled the protections. (the flags which are set are CUV,UTD and UTC, the temperature at the auto refresh main panel shows -273 degC and the voltage shows 0 mV) . how can i solve it ?

Best Regards,

Arkadi

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BQ40Z50-R1: learning cycle

September 18, 2019, 6:50 am
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Part Number: BQ40Z50-R1

attached is the confifuration file

I am using the BQ40z50-R1

I charge the battery between 10.8V and 14.6V, LiFePO4  13Ah (4 cells in series, 2 blocks in

parallel – 4S2P).

The chem ID is not very accurate(see attachment) and  the learning cycle failed ( Q max is updated,  but  LStatus() is not 0x05 after “  Relax for at least 2 Hours” see slua848, Ra is also updated but LStatus() is not at 0x06).  

Can you tell what I am doing wrong? Is there a mistake in the configuration settings

 (Please visit the site to view this file)(Please visit the site to view this file)

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BQ24040: bq24040 about CHG and PG status

September 18, 2019, 7:19 am
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Part Number: BQ24040

Dear,

We saw the bq24040 datasheet, but some question as below:

1. CHG status, if didn`t charger was Open Drain, if current charger was low, also full charger was Open Drain?

2. PG status, If Vin didn`t connect was Open Drain?, If Vin was connect USB so 5V was low... have other setting can change mode?

3. PRE-TERM, If Battery was 450mAH, 4.2V , could suggestion setting percentage?

if any suggestion, Please advise me.

Thanks,

Best regards,

Lawrence.

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TPS53681: NOT ABLE TO PROGRAM NVM

September 18, 2019, 6:43 am
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Part Number: TPS53681

Hi All,

In the tps53681 mutiphase datasheet, the (USER_DATA_00 - USER_DATA_12 ) is mentioned as read and write only registers. But we are not able to write through i2c commands.i.e.., B0h - BCh. Please help us to resolve this issue and let us know if any sequence to be followed for writing these registers.

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TPS548D22: Power management forum

September 18, 2019, 6:51 am
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Part Number: TPS548D22

Hi,

For the loop instability of TPS548D22 in our design, please refer to the link below：

https://e2e.ti.com/support/power-management/f/196/t/839446

I would like to ask further questions. Except for the output capacitors as attached schematic, there are also some capacitors in the output of 0.9_Vcore as shown below:

 

For its urgency, now power team need to choose a solution ASAP. For two options below, could you help to evaluate its efficiency and feasibility： 

   1. Imax=10.7A

   2. remote sense is from the load side.

Option1：keep 1uH inductor, and reduce the capacitance of the output capacitor

Option2：change 1uH to 400nH ,no other changes

In the option1, to improve loop stability,  how much capacitance should I put in the output? How can I modify this design to get better performance? we want to know how much margin we have with 1uH 1/2R combination. Because you know we have 20% tolerance of each inductor and we suspect increasing inductance will induce such kind of instability.

In the Option2,  new material purchasing L/T will be 18wks or more, which seems is not suitable for the short term mitigation. So can you help to evaluate the impact of this change on the loop instability? If this option is more suitable to address the ripple issue caused by instability, then we will push to buy 400nH inductor immediately.

We look forward to your early reply. So it will be better that you can leave your contact details so that we can discuss further. Thanks.

Yakun

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TPS54332: Compensation circuit

September 18, 2019, 7:28 am
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Part Number: TPS54332

Hi, I'm attempting to calculate the compensation components for the TPS54332.

I'm having issues with the phase loss calculation in the datasheet (equation 22): From the numbers that are in the datasheet, I should end up with a phase loss of 93.94 degrees. but I never get this result.

Could someone from TI help me with this?

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TPS51116: FET Voltage

September 18, 2019, 7:42 am
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Part Number: TPS51116

Hi team, 

We are using the TPS51116 with two external FETs with a VGS rating of +/-20V; the proposed is +/-12V.

It seems like the DRVH is set in relation to VBST and configures the source voltage for the high-side FET. Our VIN is 5V, can you determine what the voltage will be at the source of the FET (LL pin)?

Thanks,

Arthur

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BQ40Z50-R1: On 1S3P pack, bq loses communication on CUV condition.

September 18, 2019, 7:49 am
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Part Number: BQ40Z50-R1

Working with a pack of 3 parallel-connected cells and attempting to discharge the pack to the minimum cell specification (2V). I've had to adjust CUV upward from 2V to ensure the bq remains above its operating voltage (2.2V). Every time the pack crosses CUV, the chip goes unresponsive to bqStudio despite having adequate voltage to run the chip (e.g. 2.4V). I've adjusted all "Power" thresholds far below 2V to ensure they don't function and CUVC is disabled.

How do I ensure I can reach CUV without the chip shutting off?

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BQ40Z50-R1: Where is "FlatVoltMax"

September 18, 2019, 8:04 am
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Part Number: BQ40Z50-R1

The bq40z50-R1 Technical Reference Manual mentions an OCVFR-relevant value called "FlatVoltMax" yet bqStudio does seem to reveal this value.

Where can this value be found and possibly changed?

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BQ76940: BQ76940 adjacent cell change in the balancing

September 18, 2019, 8:23 am
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Part Number: BQ76940

Dear  All：

    Why does the cell voltage change during balancing? In my application, when i balance the  cell, i find the adjacent cell voltage is high more than normal,  I worry that this will affect my  software  judgment of OV or  balance. I can't modify the hardware,  Do you have any good advice to solve  this problem by modifying the software code？ Thanks！

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BQ25120A: I2C register [SYS_VOUT, BUVLO] questions

September 18, 2019, 8:39 am
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Part Number: BQ25120A

Hi -

1) For SYS_VOUT register, can you clarify what is the mV step size when SYS_SEL = 00 or 10. Table 18 says 00 has 1.1V and 1.2V selection, although in table 19 with SYS_SEL=0, SYS_VOUT goes upto 2.33V. 

2) ILIM and BUVLO register has BUVLO = 2.2V for both 110 and 111. Is that correct?

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BQ27Z561-R1: Cell0 R_a and xCell0 R_a

September 18, 2019, 8:39 am
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Part Number: BQ27Z561-R1

Hello team,

Why sometimes xCell0 R_a is different from Cell0 R_a? Is that normal? What cause it?

I did two low temp discharge test. The first test has same Ra , but the second has different Ra, as shown below.

Thanks,

Miranda

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LM2991: LM2991S

September 18, 2019, 8:42 am
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Part Number: LM2991

HI,

I have a question of LM2991S, on the Silicon Expert. This device is obsolete.

I find it is still active in your website. 

Can you check the lifecycle of LM2991S?

Thanks for your help.

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BQ4050: Gas gauge calibration issue

September 18, 2019, 8:42 am
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Part Number: BQ4050

Hi all,

We designed a board that looks like tida-00982.

It is based on bq4050 gauge and bq24600 charger.

We use a 2S battery pack with the following characteristics:

   - Design capacity: 3000 mAh.

   - Design voltage: 7.4 V.

We use bqStudio and EV2400 to setup the bq4050. So we follow the video https://training.ti.com/bq40z50-setup-and-going-production.

We set:

   - DA Configuration.

   - FET Options.

   - Temperature Enable.

   - Temperature Mode.

   - Enabled Protections A.

   - Enabled Protections B.

As follows:

   - CUV.

   - COV.

   - ASCC.

   - ASCD.

As follows:

   - Power.

   - Shutdown.

As follows:

   - Low Temp Charging.

   - Standard Temp Charging.

   - High Temp Charging.

   - Rec Temp Charging.

As follows:

   - Design.

   - TD.

As follows:

When we rich the calibration step, we measure the Cell-1 voltage (3950 mV). And in calibration tab, we check "Calibration Voltage" and press on the "Calibrate Gas Gauge" button.

The result is an error message "Calibration - Cell 1 measured voltage in millivolts is out of range".

Is there any missing setting or configuration ?

Thanks.

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BQ76920: the impedance of SCL to GND is very small

September 18, 2019, 8:49 am
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Part Number: BQ76920

Dear TI Experts

I am now using BQ76920 and met with a problem:

When power on, we found that voltage cannot be read.

And we take off the chip and  found that  the impedance of SCL to GND is very small, it feels like being broken down

The SDA is normal~

Can I know how does SCL be broken down?

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BQ25601: Programmable system reset

September 18, 2019, 9:06 am
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Part Number: BQ25601

Hi,

Have some quick questions on the BQ25601.

1. Is tQON_RST (min 8s) programmable? This was programmable on BQ25120s.
2. Is it possible to initiate a system reset through software by writing to a register?  
3. Is the tBATFET_RST value (250ms) programmable?
4. Is the tSHIPMODE (1.1s) value programmable?
Thanks.
Hrishi
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BQ76940: Adjacent Cell Balancing with 9 cells

September 18, 2019, 9:12 am
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Part Number: BQ76940

Good day,

From the datasheet, at the bottom cell group:

VC1–VC0 is CELL 1
VC2–VC1 is CELL 2
VC3–VC2 is SHORT
VC4–VC3 is SHORT
VC5–VC4 is CELL3

There is a note that adjacent cells should not be balanced simultaneously. My question is; Is CELL 3 considered adjacent to CELL 2? If no, that means I can enable balancing on CELL 3 without worries about adjacent cell balancing, right? (since CELL 4 will be on another cell group)

Thank you very much,

Robert

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UC3842: About the switch frequency

September 18, 2019, 9:37 am
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Part Number: UC3842

Hi 

We use UC3842D8 to design a 60W/（15V output） power supply. We design the switch frequency is about 100K, but when we test (only 15V output is loaded),the frequency is 20~30Khz, especially 3kHz with no load. 

Below is the schematic and some test waveform. I have two question that need to confirm:

1. Is the switch frequency fixed by the RT & CT , anyway different input or load ? 

2.Does the schematic need to improve ? 

(Please visit the site to view this file)

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TPS65911: TPS6591131A2ZRCR alternative

September 18, 2019, 9:51 am
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Part Number: TPS65911

Team, 

It seems we have changed PN from TPS6591131A2ZRCR to TPS6591133A2ZRCR. Can you please confirm that this is just a part number update with no change to the silicon or footprint?

Thanks

Viktorija

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TPS23754EVM-420: Transformer parameter

September 18, 2019, 10:06 am
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Part Number: TPS23754EVM-420

Hello,

Please provides the detail parameter of the transformer used in the TPS23754EVM-420, my customer need provide it to transformer factory, thanks.

by the way, if the transformer's size is not suitable to customer, example change the transformer bobbin, and how to design the transformer ? the datasheet and EVM not describe how to design transformer.

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