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BQ28Z610: Sense resistor selection, I2C interface and ESD questions

December 11, 2018, 8:32 am
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Part Number:BQ28Z610

Hi Support team

I am getting lots of questions from my customer on this part, the part is currently in production in many different products as well as being designed into new products. 

On the sense resistor, why are we limiting the customer to 0.001~0.003 ohm resistors, customer wants to use a 0.01 ohm resistor, (not sure why yet). Is it because of the adc input range, or the safety features in the BQ28Z610?They are not using the safety features and have an 4 amp fuse in the product. 

On the I2C interface, data sheet, section 7.26 mentions a 3.3k pull down, am assuming that is a typo and should be a pull up, or is the pull down active when power is removed from the BQ28Z610?

Still on the I2C interface is the filters that were added, the 2 100 ohm series resistors and the esd devices. When doing the math, it appears we are not able to provide a valid low to the host processor. Any comments on this?

Regards

Jeff Coletti

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TPS61161: What is the nominal/typical feedback current into the TPS61161?

December 11, 2018, 8:45 am
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Part Number:TPS61161

I have an application for the TPS61161 in a purely Boost DCDC mode (voltage output - not an LED string):

30V boost - want to minimize current in FB divider - currently set to about 35uA.

I have feedback in the system to adjust output (voltage) level using pwm. 

If I knew the FB bias is 1-2uA rather than 0-2uA, that would be helpful.

I would like to increase the FB resistors if possible, and knowing this information can help me with tolerances.

Thanks!

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Linux/BQ24780S: Device Driver

December 11, 2018, 8:58 am
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Part Number:BQ24780S

Tool/software: Linux

Hi ,

We are planning to use BQ24780s chipset in our custom board, Not able to find the driver for BQ24780 in Linux source tree?

Is there any separate driver available in Linux source or any existing driver has the compatibility ? 

Please share the Linux driver source path. 

Thanks,

Senthil

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TLV704: Higher fixed Vout

December 11, 2018, 9:04 am
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Hi All,

I have a customer who is asking if the TLV704 can operate at higher Vout via a zener diode to the gnd pin.  I'm not sure what the Vout pin is rated for but they are looking for low cost, SOT23 solution for a 6.0V rail.  The TPS70960 apparently is too costly for them and I haven't been able to find another cost effective adjustable solution with comparable specs.  Please let me know if you have any ideas/inputs.  A longer term option is if the TLV704 can be designed for a fixed Vout of 6.0V?

Please let me know what you think.

Thanks & regards, John Garrett, TI-AFA

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BQ51051B: Off the shelf transmitter options and compatibility

December 11, 2018, 9:38 am
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Part Number:BQ51051B

I plan on using the BQ51051B for a BLE based sensor that can be charged wirelessly. However I would prefer to use a off the shelf wireless power transmitter instead of building one from scratch. I am looking for suggestions of such product (if any) references or recommendations. 

Any recommendations that can help reduce the design and development effort on the transmitter will also help, in case there are no ready-made transmitter that can be used. 

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BQ76930: What can prevent boot up from Ship Mode?

December 11, 2018, 11:02 am
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Part Number:BQ76930

Hi TI,

Our group is working on a battery management module using the BQ76930. We are having issues when it comes to booting the chip from SHIP MODE.  Currently there is no battery or a resistor bank connected to the cell input ports. I am working on establishing the I2C communication first and have been unable to consistently boot up. On the TS1 pin, there is a voltage divider with a switch that can provide 1.1V pulse. 

Can you please provide me with a check list that need to be available for the BQ76930 to boot? What can prevent it from booting?

Thanks,

Mesfin 

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TPS40140: Layout of GND versus PGND.

December 11, 2018, 11:19 am
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Part Number:TPS40140

I'd like to get an example of a layout in a single ground system with a multilayer board where I can mitigate switching noise from the PGND getting into the GND of the controller.

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BQ24085: Battery absent detection doesn't work

December 11, 2018, 11:36 am
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Part Number:BQ24085

I don't see any resolution to the previous STAT2 output issue with the BQ24085.

This part works correctly on power up and charging, but if the battery is removed the two STAT signals should go open.

Instead, the STAT2 stays on. 

I placed a 2 Mohm and then a 3 Mohm resistor from OUT to VSS but it stays the same.

Any ideas?

Terry

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TPS23880: TPS23880 auto-mode

December 11, 2018, 11:42 am
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Part Number:TPS23880

Hi,

For the simple application like PSE injector, customer intend to use TPS23880 only without MCU.

1. But for TPS23880, it still need MCU for initial config, am I right?

2. How about suggest customer reserve pin 52 for TI's auto-mode version and just waiting for product release?

3. Is there anyway to do PSE injector in auto-mode without MCU?

 Thanks,

C.T.

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UCD74111: Power dissipation for sense resistor of AVGG

December 11, 2018, 12:02 pm
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Part Number:UCD74111

All,

Please confirm the size resistor that should be used for AVGG.  I see it is recommended between 1 and 2 ohms however what wattage value?  I found this used on a schematic for the UCD74120: RES, 2.2 ohm, 5%, 0.063W, 0402.  Is this correct for UCD74111? Is it the same recommendation?  Also the data sheet says use a resistor between 1-2 ohms?  What is the tolerance for this value as I found the referenced resistance value above in a schematic for this part on TI.com.

Thanks, 

HSG 

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UCD9222: Over Current Limiting when used with the UCD74111

December 11, 2018, 12:09 pm
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Part Number:UCD9222

Hi,

Because I am using the UCD74111 and it already has a high speed comparator for the current limiting is there a reason to enable the comparator (associated with CS1A, CS2A)  within the UCD9222 controller or is it best to have this disabled?

Thanks,
HSG

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LMG3410-HB-EVM: Access to Library Files

December 11, 2018, 12:17 pm
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Part Number:LMG3410-HB-EVM

Hi,

I bought the  LMG3410-HB-EVM Half-Bridge and LMG34XXBB-EVM Breakout Board EVM. I'm trying to use parts of these to build a pcb of my own. The altium files online seem to be read only, and I don't have access to the pcb libraries or schematic library. Specifically, I was wondering I could be provided the libraries below, since I'm trying to save some time, and building these connectors on my own may be risky. (If it's easier I could search through all the files you have for these two parts and find it myself.)

Libraries/part:

Connectors_Mill_Max.IntLib

Connectors_Molex.IntLib

Pin Receptacle, .032-.046" .075" Dia, Gold// TH 0312-0-15-15-34-27-10-0// Mill-Max

Receptacle, 2.54mm, 6x1, Gold, TH 448120024 Molex

Thanks!

Harish

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BQ24120: Is there a safe operating condition without input power?

December 11, 2018, 12:58 pm
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Part Number:BQ24120

We're hoping to use this chip for a new design in a single cell LiPo battery charger. Having read both the data sheet and the application guidelines, we're not certain as to the safe operating conditions with a permanently connected battery but only sporadically connected input power. For instance, is the state of the CE pin important while there is no input power? Can the chip be operated at all under these conditions, i.e. battery connected but no input power.

A quick test seems to suggest that the chip is not particularly happy that way.

Please advise. Thank you.

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TPS560430: Output Capacitor Design

December 11, 2018, 1:05 pm
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Part Number:TPS560430

Hello TI Team, 

I am using the TPS560430 for an automotive application. 

It will have a max voltage input of 18V @ 250mA and will convert the voltage into 5V. 

The output capacitance is stated to be 22uF for 5V, so my design includes 3 10uF Ceramic Capacitors (GRM188R61C106MA73D) in parallel. 

Two of the capacitors are close to the output of the regulator, while the third capacitor is closer to the micro-controller.  

The reason for that is the regulator is supplying power to the transmit VDD of an NFC chip, so I want as stable as possible. 

Will my setup affect the output performance of the regulator and/or the NFC chip?

Thank you and Best Regards, 

Joe

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WEBENCH® Tools/LM3429: WEBENCH result issues

December 11, 2018, 1:47 pm
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Part Number:LM3429

Tool/software: WEBENCH® Design Tools

Design Constraints: Custom LED Vf=12.4V, If=1.05A, Rd=1.3ohm.  3-Series, 1-Parallel, Vinmin=8, Vinmax=32, Ta=30C (CREE XHP35)

Can someone run these constraints and send me the generated design.  I  don't always get consistent results and at times WEBENCH will not generate a design for the LM3429 device.  

I'd  like to compare results to confirm I'm not missing something.

Cheers.

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TPS544C20: Leakage Current on CNTL Pin

December 11, 2018, 2:15 pm
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Part Number:TPS544C20

Hello,

This is in addition to this thread which I believe has already been close: 

Does the leakage current change over temperature?  Is there data showing how it changes over some variable like temperature?  

Thanks!

Russell

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TPS54202H: Safe as a "flybuck"?

December 11, 2018, 2:47 pm
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Part Number:TPS54202H

I'm using this device as a "flybuck", where instead of the inductor I have a 1:1 transformer providing another isolated supply.  Both supplies are hardly being used right now, very light loads, yet the TPS54202 just blew up.  I don't see a problem in the circuit (but will keep looking), but I want to check if this device is okay as a flybuck. 

The big difference between buck and flybuck as far as the controller is concerned is that the SW pin current goes negative (i.e. into the controller) during the portion of the switching cycle when the lower switch is on.  (see TI app note  )  I don't think this is a problem, but I'm not positive of that.

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LMG1205: LMG1205 with MOSFET.

December 11, 2018, 3:54 pm
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Part Number:LMG1205

Hello,

I hope to operate an half-bridge MOSFET with LMG1205 @7Mhz. Is that possible to apply to MOSFET? I'm using BSC160N15NS5. 

 and I already make own test board below. (I changed C30 to 2.2uF with 1uF). and I didn't put the L4 and caps. I hope to check the output signal first.

But the output signal is not stable below. It has a 7Mhz square wave but the envelope of the signal is not stable. What is the problem with this design...? Could you advise to me?

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BQ24610EVM: New board, charging slowly, then stops after 30 minutes

December 11, 2018, 4:06 pm
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Part Number:BQ24610EVM

I just got a new evaluation board. It's currently in its default configuration.

18VDC input, 1p4s battery connected, 12W load on Vsys, 1.7V power supply connected to TS.

At first, the battery will charge slowly (with and without the load).

Then, at the 30 minute mark, the battery stops charging. If the load is connected, the battery drains. Disconnect battery, load stops.

I have to disconnect/reconnect Power Supply to TS and the 18VDC to resume charging.

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UCC28063: UCC28063 VINAC

December 11, 2018, 4:08 pm
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Part Number:UCC28063

Hi TI expert,

Sometimes, Surge testing damages UCC28063.

So I would like to place zener diode(6.8V) to VINAC and GND. is it OK?

Please let me know if there are any side effects.

Thank you.

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