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bq27541-V200: "SOH Status" = 0x00 and SOH not changing.

March 3, 2015, 1:19 pm
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The datasheet (bq27541-v200.pdf, page 15)  describes the parameter "SOH Status" at address 0x2f. 

When I read this parameter, its value is always 0x00.  I believe I have properly configured the gauge.

I did a test to see if the SOH would change (despite the SOH Status is not valid).  See the figure below.

I configured the fuel-gauge to a battery with 2-parallel cells (design capacity = 4540mAh).  I did the steps in the bqEasy wizard to create the golden image.   I flashed this golden image and enabled IT (0x0021) and sealed (0x0020).

Then I removed one of the cells to halve the capacity of the battery.  Using a Cadex C7400 C-Series analyzer, I cycled the battery multiple times.  The charge and discharge rate is about 0.3*C = 1.3A.  There is a 30 minute rest after charging and after discharging during each cycle.

I expected the SOH to decrease to about 50% after several cycles, however it remains at 100%.  SOH Status is still 0x00.

Did I miss a step or mis-configure something? 

Here's my gg file (removed auth codes). (Please visit the site to view this file)

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bq27421- odd behavior

March 3, 2015, 5:05 pm
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A few more questions related to bq27421:

1. The gauge is in the design created a while back, before the datasheet and tech manual mentioned not to ground BIN pin directly on the gauge.So that pin is grounded. Battery is always present and is not removable.   After power up we do not see anything weird on the LDO output pin, and BATDetect bit is set. The gauge is mostly behaving , and the ITPOR bit gets cleared and does not come back. So it appears no resets happen after the initial power up.What is the long term impact of that pin being wired that way?

2. The same chip does exhibits a few oddities- on reset, some NVRAM values do not match defaults. That's in a system with no processor running and only I2C communication between the gauge and EV2300. For example  "FC Set" gets changed to 127, with a valid range from -1 to 100, and the R_a0 2 value goes to -32660 despite RUP_DIS flag being set, and no RES_UP bit set. Power cycling or swapping battery to another one makes no difference. 

3. On a chip with v 1.0.9 of firmware a bunch of data ram registers come up with values differing from defaults listed in the manual (and from v 1.08 chips). Again this is after POR and no other comms. 

     1.09                                    vs              1.08
Min DOD Res Update = 6              Min DOD Res Update = 70
Hibernate V = 2072                        Hibernate V = 2200
Dsg Current Threshold = 39         Dsg Current Threshold = 167
Quit Current = 58                            Quit Current = 250
Transient Factor Charge = 51      Transient Factor Charge = 179
Transient Factor Discharge = 51 Transient Factor Discharge = 179        
Max IR Correct = 272                      Max IR Correct = 400

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bq34z100 - Automatic offset calibration

March 4, 2015, 10:06 am
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Hello,
I'm trying to understand how and when the automatic offset calibration will occur and I'm totally confused.

According to SLUA664:

  1. the automatic calibration, Board Offset, is done the first time the I2C Data and Clock is low for more than 20 seconds, which is a much more accurate calibration.

  2. During normal Gas Gauge Operation when the I2C clock and data lines are low for more than 5 seconds and Average Current is less than Sleep Current in mA, then an automatic CC Offset calibration is performed. This takes approximately 16 seconds and is much more accurate than the method in Calibration mode.

  3. When Average Current is less than Sleep Current or greater than (–)Sleep Current in mA, the bq34z100 enters SLEEP mode if the feature is enabled (Op Config [SLEEP] = 1). The bq34z100 does an analog-to-digital converter (ADC) calibration and then goes to sleep.

Thus, in order to obtain a Board Offset calibration, should I drive low both SCL and SDA for more than 20s, keeping the bus stuck?

What kind of calibration is nr. 3? Since it's not talking about I2C state, I expect it to be something different from 1 and 2.

Then, if I read the datasheet, it states:

The gas gauge performs a single offset calibration when (1) the interface lines stay low for a minimum of Bus Low Time and (2) Vsr > Deadband.

What's Bus Low Time? Is it tBUSERR? In any case, what's its value? 20s? I can't find it specified.
Is the "Vsr > Deadband" condition overlapping the previously mentioned "Average Current is less than Sleep Current in mA" (meaning that if current is 0 and Deadband is not 0, no calibration will be started)?
Also, Deadband is reported to be a current (mA) and here it's compared to a voltage.

Can you please clarify the way automatic calibration starts?

Thank you,

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BQ78350 - PRECHG pin

March 4, 2015, 10:56 am
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I'm bringing up a new design using the BQ78350 + BQ76930 chips and having issues with the PRECHGb pin on the BQ78350. The datasheet (SLUSB48) states that the pin has an internal pull-up to 2.5V when it is set as active high output, and is an open-drain when set as active low. I'm using the BQStudio software to play with configurations during these tests.

From what I can tell, there is no internal pull-up. If I externally pull the pin up to the 2.5V source from the BQ76930 everything behaves as expected; including correct polarity of the PRECHGb pin based on settings in the FETOptions() register when I test it using the MAC PCHG-FET command.

Adding a pull-up on the next rev of the board is not a big deal, but I wanted to check if there is another setting I am missing besides the enable and polarity bits in FETOptions() which is required to use the internal pull-up.

Thanks,

-Barrett

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LCD for BQ20Z655

March 5, 2015, 7:39 am
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Hello,

do you have any suggestions about the LCD which i can use with BQ20Z655?

it's very urgent for my Project

Best regards

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bq76940 REGOUT problem while charging

March 6, 2015, 12:15 am
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Based on the bq76940EVM we have developed our own BMS, which works fine while discharging the battery. We are facing problems while charging the battery. The REGOUT from the AFE (2.5V) which powers the host bq78350 is getting affected only when the charger is connected. A noise of 100Khz is getting induced.

This causes SMBus communication to  go haywire since the host is not powered properly. When connected with the EV2300 it shoots up "Not able to find a free communications adapter" error.

Tried probing just the charger we got a perfect DC. Any ideas what is causing the problem ?

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BQ76940 short circuit results shut down

March 6, 2015, 1:25 am
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I have a question that when I test short circuit function with BQ76940EVM, it always results system shutdown which means the BQ76940 IC even cuts the communication and stop providing power to the BQ78350. I never have chance to see the ASCD status on and when I boot up the system again, it looks normal even no indication in the PF data log. So is there any way that can just open the DSG FET without shutdown the power when detecting the short circuit and it there any way that the host controller can tell there is a short circuit condition in the system? 

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BQ34Z100-G1 RAC and masking alert

March 8, 2015, 8:26 pm
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Hi

My customer is using the BQ34Z100-G1, in the four LED format, led not always on (LED/COMM Configuration Bit 3 is clear)

We are using the datasheet SLUSBZ5 –JANUARY 2015

He would like to set-up the gauge to  automatically light up the LED when the capacity hits below 25%.

Therefore he needs to onlyset alert for lesser than maybe 25% of batt capacity .

I would like to check with you the following:

  • Is the RCA mentioned the datasheet, page 40/60 set by the SOC1 and SOCF (found on page 25)? Is this the right place to set the threshold for less than 25% capacity?
  • On table 22, there are a list of alerts that are Or-ed together. How do we mask off the alerts that are not needed?

Ivan

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BQ33100 Charging

March 9, 2015, 3:35 am
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Hi.

I want to use BQ33100 for 5 Super Caps management.

I check BQ33100 using EVM board, and 5 Super Cap voltage is 2.8 * 5 = 14V

But charging voltage is about 10V, so Super Cap can not be fully charged.

How can I get charging voltage is upper 14V?

Please let me know.

Thanks

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bq27541

March 9, 2015, 8:38 am
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Can the bq27541 be used when re-programed as a -B1 part.

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Intermittent connection bqstudio with bq34z100 chip

March 9, 2015, 12:48 pm
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I am having an issue with connecting to the bqstudio software with my bq34z100 chip. I'm using the circuit recommended on the datasheet and I'm having an issue with having a constant connection and my address seems to be incorrect as well.

The address for the auto-connected device is 0100_0_06 and sometimes 0000_0_06 and I'm told that it must be 0100_0_16, which makes sense since I'm using the 0100_0_16-bq34z100G1.bqz file. When I get to the main page, I leave the auto-refresh on, and I can read some values like temperature and I can see the device and fuel icons light up and I can see "bq34z100" by the chip icon, and then it kicks me off and the icons disappear and after a few seconds and then the Target Selection Wizard pops back up and I start all over again.

I've also tried to program the chip with the new firmware, but I'm not sure if I'm getting through because I keep losing connection, so that could possibly be an issue, but it wouldn't seem to make sense why I keep getting the wrong address...

I'm using the EV2300 v 3.1m where I was told that the most recent update it v 3.1r, could it be that my EV2300 is not up to date?

thanks in advance!

Jacob Dubie

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BQ40Z60 Evaluation Board Max error - state of charge 100%

March 9, 2015, 1:58 pm
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Hi,

I am testing a BQ40Z60 evaluation board with 2s cells. I changed the jumper J4 to 2S and set DA Config (CC1 and CC0) and set the cell cemistry correct.

I also did temperature and Voltage calibration. It is also possible to charge and discharge the cells (just tested with power supply and some LEDs)

My problem is, that the Max error = 100%, Relative state of charge = 100%, Absolute State of charge = 0% all the time.

Do I have to perform a learning cycle? If yes, how can I do it.

Best regards

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BQ77PL900 I2C to Arduino

March 9, 2015, 9:21 am
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Hello,

I am struggling to set up I2C communications between an arduino and a bq77pl900evm-001 evaluation board.

Is there any C example code for the sequence of data that should be transmitted and expected in return for reading and writing registers in the bq77pl900?

The datasheet says the order of bytes for reading a register is:


1. slave   - what is this? is it something i send or the slave sends? It is clearly the slave address since it is 7 bits + R/W

2. Register address

3. slave address

4. slave drives data

5. master drives NACK and stop.

I do not know where this differs from standard I2C and if the standard I2C library for arduino will need modification to work.



I am using windows 8.1 and the TI software (drivers) that came with the EV2300 does not work. Is there some way I can see if the evaluation board has booted?

There are no LED's on the board.

(I have connected the battery voltage to the Pack+ pin and removed it again.) 

Thanks

Regards

~Jeran

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LabVIEW Support for EV2200

March 10, 2015, 7:30 am
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We already have bq2040 to communicate with EV2200 using SMBus to extract data from our batteries here at Zoll Medical Systems.

I am anxious to find out if you have any advice or links on how to do exactly the same thing using LabVIEW VIs.

Suggestions on how to initiate communication with the EV2200 would also be helpful.

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Need BQ769x0 Register Reference Manual

March 10, 2015, 11:09 am
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My customer is looking for the reference manual for the bq769x0 devices. They are planning to use their own microcontroller to drive it (option shown on the bq769x0 datasheet), but need to have the details for the registers and command/responses. Checked the web site, and it only has the datasheets and an example MSP430 I2C communication with CRC app note. Note: They are looking at the BQ76920 and BQ76930 devices.

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BQ34Z100 FLASH CORRUPTION

March 10, 2015, 5:55 pm
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Hi,

I have faced an issue in BQ34Z100 after 7 cycles of complete calibration. At the 8th cycle the calibration is failed and in the Data flash CODES SECURITY section all the parameters RESET to 000000. Can anyone faced such an issue? Please suggest me what the possibilities are for flash Corruption? Is there any fix for the same?

In Codes Security say Sealed to Unsealed field should be 36720414 but it is 00000000 like that entire section is 00000000. After this event i was trying to import the golden .gg file, i can import but once i pressed write all option other tabs like configuration, gas gauge are changed except codes security section, while importing it is 36720414 upon write all it will become RESET to 00000000

Note:Even if the codes security section all fields are 00000000 gas gauge IC completed 3 more successful calibration.

Regards

Prakash

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BQ20z95EVM : No communication with EVM Gas gauge...

March 10, 2015, 10:05 pm
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Previously I connected bq20z95evm with EV2300 and it worked. But now I have problem when I connect and start bqEVSW shown as following picture.

I have no idea what wrong I've done, I just connect Them normally. And how do i know if it broken?

Thank you

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Full Charge Capacity

March 11, 2015, 1:05 am
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Dear Tier,

My customer used BQ20Z80+ICR18650-25F in the prior project.
Currently she is designing a combination of BQ20Z90 + ICR18650-30A(Cell).

I have two questions.

1. Is it available to modify FCC or RC value by firmware? In my thought, those values are automatically calculated by BQ20Zxx, so we cannot modify them. Am I right? If we can change, how can I do?

2. My customer faced the FCC value cannot reach 100% in the combination of BQ20Z90+30A when she use the same firmware with BQ20Z80+ICR18650-25F. It seems to be due to the difference of FCC minimum variation : BQ20Z80 of 35mAh and BQ20Z90 of 200mAh. Under the current design status, firmware change is not possible. So she want to know how to reach the 100% of charge status without firmware change. Is there any solution to solve this issues in the battery side?

I need your reply ASAP.

Best regards

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BQ27520-G4 / incremental read

March 11, 2015, 7:44 am
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Hi All,

Our customer evaluate bq27520-G4 and they plan to read register by using incremental read. Then can we read register through Temperature( ) to StateOfCharge( ) continuously? Please let me know if you have any concern.

Best Regards,

Sonoki / Japan Disty

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Can the BQ76930 be used only for voltage monitor & cell balancing?

March 11, 2015, 1:41 pm
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Greetings,
I like the look of the BQ76930 for voltage monitoring and balancing, however it won't work for me for overcurrent protection.

Is it possible to use it only for these features and have an external overcurrent protection & FET control?

Thanks!

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