LMZM33603: Separating AGND and PGND?

December 10, 2018, 6:11 pm

≫ Next: LM5146-Q1: Why 2 caps on SS_TRK Pin?

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Part Number:LMZM33603

Guys, I am working with a customer and have the following question on layout for the LMZM33603. 

The layout and pin descriptions say to keep AGND (zero reference) separate from PGND (power ground) on the LMZM33603.  Recommendation is NOT connect them together. BTW, this board also has an LMZ34002RKG on it.

In the design, everything is referenced back to the input supply (24V wall wart) and chassis.  I think we can keep AGND isolated from PGND immediately in the vicinity of the LMZM33603, by putting a route obstruct between those planes.  this should help define return paths, but I don’t know if that’s adequate, because AGND and PGND do end up getting connected at the main supply a couple inches away. ATTACHED image has a rough idea of what the design will look like.

Questions:

1. Is this a big deal and how will it impact my performance?

2. Do you have guidance for using the LMZM33603 if it is not feasible to have isolated AGND and PGND planes?

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LM5146-Q1: Why 2 caps on SS_TRK Pin?

December 10, 2018, 6:19 pm

≫ Next: Bq24773 example code based MSP430 and schematic blog diagram requirement

≪ Previous: LMZM33603: Separating AGND and PGND?

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Part Number:LM5146-Q1

Guys, I am working with a customer on a design. When he did the webench design, the output showed qty:2 Css caps on the SS_TRK pin. Is there a reason for this? See red circle in image. Thanks!

Bq24773 example code based MSP430 and schematic blog diagram requirement

December 10, 2018, 6:42 pm

≫ Next: TPS92515HV: Vin, Iled increase --> Flicker occurs problem

≪ Previous: LM5146-Q1: Why 2 caps on SS_TRK Pin?

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Part Number:Bq24773

dear all,

do we have some MSP430 example code about Bq24773? and also need Bq24773 + MSP430 schematic blog diagram, PCB design file. could you please sharing? 

thanks so much. 

TPS92515HV: Vin, Iled increase --> Flicker occurs problem

December 10, 2018, 6:42 pm

≫ Next: TPS63802: Is feedback divider lower resistance 100kohm no issue?

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Part Number:TPS92515HV

Schematic above

VIN : 48V, (Min 46V~Max 52V)

PWM spec : 3.3V 20KHz 1024step

Dimming100%, between L2 and D7

 

VIN : 52V, (Min 46V~Max 52V)

PWM spec : 3.3V 20KHz 1024step

Dimming100%, between L2 and D7

 

When Vin increases and begins to exceed 50V, flicker occurs.

OFF interval occurs in Vsw waveform.

Where should I adjust?

TPS63802: Is feedback divider lower resistance 100kohm no issue?

December 10, 2018, 6:56 pm

≫ Next: LM317HV: support negative input/output

≪ Previous: TPS92515HV: Vin, Iled increase --> Flicker occurs problem

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Part Number:TPS63802

Hello,

There is a description which R2 should not exceed 100kohm in 9.2.2.4 of datasheet. I think 100kohm is ok because not exceed. Is my understanding correct?

We would like to use 100kohm if it is ok. If not, we will consider like 91kohm or something.

Best regards,

Toshihiro Watanabe

LM317HV: support negative input/output

December 10, 2018, 6:59 pm

≫ Next: BQ25713: VBUS and VDDA maximum current

≪ Previous: TPS63802: Is feedback divider lower resistance 100kohm no issue?

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Part Number:LM317HV

Hi team,

Does the LM317HV also can be used for negative input to negative output?

Thank you!

BQ25713: VBUS and VDDA maximum current

December 10, 2018, 7:25 pm

≫ Next: UCC28780EVM-002: Pin configuration

≪ Previous: LM317HV: support negative input/output

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Part Number:BQ25713

Hi expert,

My customer want to minimize resistor usage so they want to calculate powr consumption on VBUS and VDDA resistors for RC filter. Do we have test result for it? Or if we need to change it to 0402, is that okay for it? Thanks a lot!!

Best regards,

Ann Lien

UCC28780EVM-002: Pin configuration

December 10, 2018, 7:52 pm

≫ Next: UCC256301: about how to design for LLC transformer and primary side circuit

≪ Previous: BQ25713: VBUS and VDDA maximum current

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Part Number:UCC28780EVM-002

Hi

I am looking UCC28780EVM-002 based on GaN, and I find the RDM alue RTZ in schematics is absolutely different with the Mathcad calculation.

In mathcad, RTZ=174K,RDM=61.2K. But in Schematics, RTZ=249K, RDM=84.5K.

Why there is so large big difference?

Thanks.

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UCC256301: about how to design for LLC transformer and primary side circuit

December 10, 2018, 8:59 pm

≫ Next: UCC28950: External MOS FET drive signal, A/C and B/D timing for full bridge.

≪ Previous: UCC28780EVM-002: Pin configuration

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Part Number:UCC256301

Hello E2E,

I do like to suggest the TI's LLC device for 250-W output AC/DC power supply to our customers.
I will suggest following products;
  - UCC25630x  LLC-controller
  - UCC28056  PFC-controller
  - UCC24624  SR-controller
I have never designed LLC-converter.
Does TI have a design manual for LLC transformer?

Best regards,
ACGUY

UCC28950: External MOS FET drive signal, A/C and B/D timing for full bridge.

December 10, 2018, 9:09 pm

≫ Next: TPS563210A: TPS563210A: PCN on LBC7 change total PO thickness from 24kA to 39kA

≪ Previous: UCC256301: about how to design for LLC transformer and primary side circuit

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Part Number:UCC28950

 Hello guys,

 One of my cutomers is evaluating a full-bridge power supply using UCC28950 and UCC27714 for their next products.

 On the evaluation, they connected UCC28950 A/C output to UCC27714 input, LI (signal input for low side FET driving)

 and B/D output to UCC27714 input, HI (signal for high side FET drivin) by their PCB board design mistake.

 As the result, UCC27714 high side driver was broken.

 They will fix the miss connection by jummper and will continue the evaluation.

 But they want to know why UCC27714 high side was broken.  

 Is it problem that the gate signal on the high side turns on first at the power supply operation starting with no load?

 Could you please give me your comment what the possible cause is?

 Your reply or comment would be much appreciated.

 Best regards,

 Kazuya Nakai.

TPS563210A: TPS563210A: PCN on LBC7 change total PO thickness from 24kA to 39kA

December 10, 2018, 9:17 pm

≫ Next: TPS65911: Consult suitable PMIC to replace DA9063

≪ Previous: UCC28950: External MOS FET drive signal, A/C and B/D timing for full bridge.

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Part Number:TPS563210A

Hi TI Experts,

Our customer would like to know what mean by PO thickness?

Thanks,

Br,

Tech Me

TPS65911: Consult suitable PMIC to replace DA9063

December 10, 2018, 9:57 pm

≫ Next: TPS3809: TPS3809 Output Oscillation

≪ Previous: TPS563210A: TPS563210A: PCN on LBC7 change total PO thickness from 24kA to 39kA

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Hi Team,

Does TI have suitable PMIC to replace DA9063(which is use to supply Telechip MCUTCC8031)? Thanks a lot!

The datasheet of DA9063 is attached.

(Please visit the site to view this file)

TPS3809: TPS3809 Output Oscillation

December 10, 2018, 10:00 pm

≫ Next: CCS/UCD3138064AEVM149: why fusion desinger cannot download ucd3138a64 firmware to evm149？

≪ Previous: TPS65911: Consult suitable PMIC to replace DA9063

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Part Number:TPS3809

Hi team,

  My customer is using TPS3809K33 and met an issue regarding to output oscillation.

  I took it back set it up in TI lab as below:

  The VDD of TPS3809 is connected to a external power supply. When I manually rotate and increase the input voltage and when the input voltage hit around 2.93V, tps3809 output unstable. The waveform is attached. However when I increase the input voltage in much faster slew rate, the output is normal. It almost like the device enters in a hystersis loop and never get out.. (yellow is the VDD pin, red is Reset pin)

  I wonder what's the mechanism behind the behavior? Thanks.

Regards,

Patrick

CCS/UCD3138064AEVM149: why fusion desinger cannot download ucd3138a64 firmware to evm149？

December 10, 2018, 10:14 pm

≫ Next: BQ40Z50-R1: Balancing Configuration [CBR]

≪ Previous: TPS3809: TPS3809 Output Oscillation

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Part Number:UCD3138064AEVM149

Tool/software: Code Composer Studio

I have used  fusion gui to download firmware to evm149 bought from TI,but I cannot download ucd3138a64.xo, but can download ucd3138.x0.then the evm cannot work.

BQ40Z50-R1: Balancing Configuration [CBR]

December 10, 2018, 10:16 pm

≫ Next: LM3914: LED current difference over four times

≪ Previous: CCS/UCD3138064AEVM149: why fusion desinger cannot download ucd3138a64 firmware to evm149？

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Part Number:BQ40Z50-R1

Currently I am reading sluubc1d.pdf.
I would like to ask about cell balance ON / OFF setting.

p.55
The cell balancing at rest can be enabled separately by setting Balancing Configuration [CBR] = 1.

p.137
CBR(Bit2): Cell balancing at rest

Does 'at rest' point to RELAX mode?
Is it OK with below?

cell balance
CB: at CHARGE Mode
CBR: at RELAX Mode

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LM3914: LED current difference over four times

December 10, 2018, 10:49 pm

≫ Next: BQ27750: Data Flash Table undefined addresses confirm

≪ Previous: BQ40Z50-R1: Balancing Configuration [CBR]

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Part Number:LM3914

Hi team,

Our customer inquired large LED current difference between designed and measured value.

The attached schematic is a customer circuit aiming 3mA per channel.

The measure LED current was 136mA total.

What kinds of problems are considered?

We appreciate your help.(Please visit the site to view this file)

BQ27750: Data Flash Table undefined addresses confirm

December 10, 2018, 10:50 pm

≫ Next: TPS2547: Is it ok to leave STATUS pin open in the schematic design if the feature about STATUS pin is not used

≪ Previous: LM3914: LED current difference over four times

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Part Number:BQ27750

Dear TI Experts,

From the data flash table of BQ27750 below, we can see lots of undefined addresses, such as 0x4020, 0x4030.... when my customer conduct the DF checking during manufacture process, they find the data value of some undefined addresses is changing from time to time. Is it ok if they skip these undefined addresses, any potential risk? Thanks a lot.

TPS2547: Is it ok to leave STATUS pin open in the schematic design if the feature about STATUS pin is not used

December 10, 2018, 11:25 pm

≫ Next: primary side vs secondary feedback

≪ Previous: BQ27750: Data Flash Table undefined addresses confirm

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Part Number:TPS2547

Hi Chuck and team.

As the title, I want to know whether we can left STATUS pin open in the schematic design if this feature is not used.

Thanks a lot for your help.

primary side vs secondary feedback

December 10, 2018, 11:32 pm

≫ Next: BQ25895: BQ25895 consumed solar cells was relatively high,

≪ Previous: TPS2547: Is it ok to leave STATUS pin open in the schematic design if the feature about STATUS pin is not used

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Dear All,

i have some questions about primary side controllers:

1) does primary side preciesly control the output voltage of a converter as common secondary side feedback?

2) what is the difference between primary side and usual feedback converters?

3) what advantages does offer primary side compare to usual feedback?

4) in which applications it is best to select primary side controllers?

Best Regards,

Ras

BQ25895: BQ25895 consumed solar cells was relatively high,

December 10, 2018, 11:39 pm

≫ Next: UCC25630-1EVM-291: Indy use requires more caps to output

≪ Previous: primary side vs secondary feedback

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Part Number:BQ25895

Hello,.
         In the course of testing, we found that when BQ25895 was input to solar panels, when the input power of BQ25895 was low, the current of 25895 sometimes up to 1.xmA. See annex, the picture is the input waveform of BQ25895. I would like to ask what causes excessive battery current consumption in this state, and how to avoid it reasonably. Thank you for your support！

(Please visit the site to view this video)