Quantcast
Channel: Power management forum - Recent Threads
Viewing all 35901 articles
Browse latest View live
↧

TPS7B4253-Q1: tps7b4253-q1 voltage clamp function

May 24, 2019, 12:15 pm
$
0
0

Part Number:TPS7B4253-Q1

Can I use this device to track the input up to a specific level and then regulate at that level?  Application is in powering a sensor with a max voltage of 30V.  If load dump is 34V I'd like to use this device to power the sensor through load dump.  The regulator would track VIN up to 27V and then regulate the output to 27V.  I think I can use the FB pin and ADJ pin as illustrated in the attached TINA-TI file.  Please confirm.  Thank you, John(Please visit the site to view this file)

↧
Search

UCC23513: UCC23513 specification questions

May 24, 2019, 12:20 pm
$
0
0

Part Number:UCC23513

Hi team,

Please clarify followings.

- VF vs. IF monotonicity
   In the data sheet, VF has min/max value in 7mA - 16mA. Does this mean VF(min)=1.8V corresponds to IF=7mA, and VF(max) corresponds to IF=16mA?

- IFLH
  We see contradiction between max(IFLH)=4mA and min(IF_ON)=7mA. How should we understand this difference? and How could the device behave in 7mA>IF>4mA?

- Decoupling cap
  What is the recommendable value of decoupling cap on hot side Vcc - Vee? Is it 1uF? If 0.1uF is used as decoupling, how the device could behave? (degraded in CMTI, etc.?)

Best regards,
Iwata Etsuji

↧
↧

TPS82084: Output noise

May 24, 2019, 1:15 pm
$
0
0

Part Number:TPS82084

Team, 

My customer would like to use TPS82084 to power some of Xilinx Ultrascale+ FPGA rails:

  1. MGTAVCC - 0.9V 
  2. MGTAVTT – 1.2V 
  3. MGTVCCAUX – 1.8V and
  4. MGTAVTTRCAL – 1.2

Their noise requirement is 10mV peak to peak noise. 

What is the noise spec they can expect from TPS82084? 

Datasheet lists spurious noise spec on page 15, but we are not sure that's the right spec to compare to Xilinx requirement. 

Your inputs would be greatly appreciated. 

Thanks!

Viktorija

↧

TPS55340EVM-017: Issues with evm board output voltage

May 24, 2019, 1:34 pm
$
0
0

Part Number:TPS55340EVM-017

Need assistance as to why the evm is being damaged perhaps:

After power up (it is configured for 24V by default) I installed a FET across R2 and was using the FET to change the output voltage.

After seeing this being functional, I removed the 187k R1 resistor and replaced it with a 59K to set the output voltage to around 8V, when I powered the board back up, I am now just getting the input voltage on my output. When I measure the resistance across R2, I am not getting 10k, the meter is measuring something through the IC I believe. This doesn’t happen when I measure R2 on the first board you sent me, I measure 10k on the first board. So I am not sure which is correct, but now I have 2 PCB’s which are not functioning. Any thoughts?

↧

TPS22968: footprint for DMG 10 package

May 24, 2019, 2:31 pm
$
0
0

Part Number:TPS22968

Hello,

I'm looking for the footprint/land pattern for DMG 10, however, there are no *.bxl files available for the products with this package: http://www.ti.com/packaging/docs/searchproductbypackage.tsp?orderablePartNumber=&packageDesignator=dmg&pinCount=10&results=results#resultspage. The datasheets of the products in this link don't have recommended footprints/land patterns either.

As I searched further, I found that DML10 has the same dimensions as DMG10: http://www.ti.com/packaging/docs/searchtipackages.tsp?packageName=SON

However, checking the package drawing of DML10 and DMG10, there is a 0.01 difference in their pin widths. Can the DML10 example layout be used for DMG10 package despite this? 

Thank you.

↧
↧

BQ4050: BQ4050 versus BQ40Z50, what is the difference

May 24, 2019, 1:33 pm
$
0
0

Part Number:BQ4050

We have noted that the BQ4050 is much less expensive than the BQ40Z50 ($1.10 versus $2.40 respectively), and we would like to know the difference in safety performance.

Additionally, it appears most new aps are using the BQ40Z50, and wondering if the BQ4050 will be supported into the future.

↧

LP8556: Audible noise and unstable VLDO output

May 24, 2019, 3:11 pm
$
0
0

Part Number:LP8556

Hi,

We are having audible noise issue from a recently build. Previous builds do not have this issue and the design did not change.

Two differences we found when comparing the current (audible noise) and previous (no audible noise) builds are:

1. The VLDO output on the current build has frequency components in the audible range. See the scope capture below.

2. The VLDO ripple on the current build is much larger (~500mV) comparing to previous build (<20mV).

Any insights for debugging this?

Thanks,

Peter

↧

BQ24770EVM-540: bq24770EVM Power-Up and Initial Checks

May 24, 2019, 6:00 pm
$
0
0

Part Number:BQ24770EVM-540

I've got my bq24770EVM setup connected.  As I'm running through the power-up and initial checks, I notice that my ACOK LED (D5) is not lit.  I have 19.5V at the input.  I'm targeting a 3-cell battery line up.  After trial and error I selected R26=100kOhms, R30=1MOhm to get 3.123V at CELLS (TP11).  Here are my initial measurements:

TP11 (CELLS): 3.12V   (should be > 3V for 3 cells)  OK

TP7 (ACDET): 2.59V (should be 2.6V +/- 0.1V)  right on the edge of the range...

D5 LED (ACOK):   NOT LIT   (however, it lights after turning on PS1=3.31V)

TP15 (REGN): 5.33V   (should be 5.5V +/- 0.5V)  OK

J3 (BAT, GND): 8.89V   (should be 1V +/- 1.1V)  WAY OFF!

TP6 (ACDRV) to TP5 (CMSRC): 6.45V   (should be 6V +/- 0.5V)  OK

Measure System Voltage for 3 cell setting: J2 (SYS, GND): 13.62V   (should be 13.5V +/- 0.6V)  OK

 

Also, after turning on PS2=3.3V, and running bqStudio, for the bq24770 charger, then trying to read the registers, I get no read back and an error message: “Device ACK Error”

-any ideas on how to bring my initial measurements in line with the expected values and also get bqStudio reading properly?  Please let me know.  Thanks,

Carl Olen

↧
Search

BQ40Z80: BQ40Z80 SOC Issue

May 24, 2019, 7:56 pm
$
0
0

Part Number:BQ40Z80

As shown in the picture, Why SOC is 0%?

All Cell have very high voltages. And I send the command 21, 41 yet. It didn't work.

After voltage calibration, Cell7 voltage still has a 100mV error.

↧
↧

TPS2561: USB2.0 requirement

May 24, 2019, 11:52 pm
$
0
0

Part Number:TPS2561

Hi team,

I want to use TPS2561 as a current limited power switch and can auto retry, there is no battery in the schematic, there are some DC/DC and MCU in the schematic. The USB port  connect to the computer, USB provides power and communication with MCU. The schematic is as below, please review, thank you.

1.whether TPS2561 can withstand normal plugging and unplugging the USB cable which connected with computer?

2.Does TPS2561 can meet USB 2.0 surge requirements?

↧

TPS2561: USB 2.0 plug

May 25, 2019, 12:10 am
$
0
0

Part Number:TPS2561

Hi team,

I want to use TPS2561 as a current limited power switch, there is no battery in the schematic, there are some DC/DC and MCU in the schematic. the USB port Connect to the computer, USB provides power and communication with MCU. whether TPS2561 can withstand normal plugging and unplugging the USB cable which connected with computer?  The schematic is as below, please review, thank you.

↧

flyback transformer design

May 25, 2019, 2:36 am
$
0
0

Hi everyone

I want to design transformer for flyback converter. I read some application notes of texas instrument like: Magnetics Design Handbook by Lloyd H. Dixon, Jr  and Transformer and Inductor Design for
Optimum Circuit Performance. they were very useful but I don't know what type of core material I should use. in their text was said : magnetics type p material used for CCM mode and magnetics type k used for DCM mode. what are type p and type k ? How can I choose the core material?

Thanks,

Zahra

↧

TPS3803: hysteresis

May 25, 2019, 3:40 am
$
0
0

Part Number:TPS3803

Dear Sir, good morning

 I use TPS3803-01. I have 1.7 - 2.4 V battery. Battery indication threshold = 1.8V.  TPS3803-01 has 15 mV hysteresis.  As soon as the battery is discharged to 1.8 V, TPS3803-01 turns off the power supply. But as soon as it turns off, the battery voltage rises slightly and  TPS3803-01 again turns on the power supply . Generation occurs. I'd like increase the hysteresis to 50 - 70 mV . Is it possible? Or can you recommend another chip? Please, see attach.

TIA

Sincerely,

Vladimir Naumenkov

www.agat.by(Please visit the site to view this file)

↧
↧

SM74611: DIode voltage range for charge pump circuit.

May 25, 2019, 9:49 am
$
0
0

Part Number:SM74611

HI, guys. I got a recommendation to add a charge pump circuit to generate a negative voltage output.

I'm new with diodes and the charge pump circuit.

I noticed that the SM74611 smart diode's max reverse voltage is 30V.

Q0. Referring to the schematic, can I use SM74611 to create that charge pump circuit?

I'm not sure what type of electrical specification I should consider.

Q1. Instead of using the TPS61175PWP, suppose I chose TPS55332-Q1 to generate 60V output.

If I try to generate -60V by using the charge pump circuit and the TPS55332-Q1, can the SM74611 apply as well?

↧

BQ76200: FET orientation...common sources?

May 25, 2019, 10:49 am
$
0
0

Part Number:BQ76200

Hello again;

Sanity check - client's current FET disconnect board has the N MOSFET's oriented with common sources. I need confirmation that I can control them with the 76200. I've Spiced a simple circuit (attached) and it appears to function as desired, by swapping the CHG and DSG signals. Am I missing something obvious, and/or do you not recommend this use case?

Note that the FET used in the sim's was used because it has very large Qg. My client's application will use 16 AUIRF7759 (8:2), 330nQ, 75V.  I'll be testing the 76200 with a mach'd-up disconnect board soon, and am hoping it can turn on these FET's. They need ultra-low Rds because they will be switching up to 400A, and the board will be in an enclosed, sealed jar, with very high TempCo to the outside. This FET family (DirectFET), appears to have the lowest theta ja I can find.   Any alternatives from TI will be appreciated.

(Please visit the site to view this file)

↧
Search

LM2596: About deviation of package's dimension

May 25, 2019, 6:37 pm
$
0
0

Part Number:LM2596

Dear all,

Would you mind if we ask about package's dimesion of LM2596T-5.0 (TO-220)?

Our customer would like to know the deviation of package's dimension.

Please confirm the figure below.

 

Do you know this deviation of dimension enclosed in red circle?

It would be great if you could let me know your thoughts on the following the question.

Best regards,
Y. Ottey

↧

LM5088: Minimum current

May 25, 2019, 10:13 pm
$
0
0

Part Number:LM5088

Which is the minimum current at which the LM5088 (-1,2) will works, can it run in discontinuous mode like LM5008?

Our requirements:
Input voltage - 10...65V
Output voltage - 12V
Output current - 0.01....5A
Don't have yet inductor (I will use recommendation from your web designer - WEBENCH)

I see that in data sheet for LM5088-1 is used freq. 250kHz, but your web designer use 533kHz.Which freq. is better to use?
I was also noticed that WEBENCH designer gives different values in schematic from those in LM5088-1 datasheet (picture 27)
for the same input parameters (in/out voltage and current), which schematics values should we use? Is it WEBENCH accurate?

If it can't run at low current, do you have IC which can achieve our requirements?

Regards

↧
↧

TPS63031: VINA connection, output when operating in Power Saver mode and disabling when implementing a higher Voltage Monitor

May 25, 2019, 10:17 pm
$
0
0

Part Number:TPS63031

Hi guys:

I'm not sure if I'm understanding correctly some parts of the datasheet, and as I'm not experienced in this kind of devices, I would like to ask you guys for help in the implementation in my use case. First, let me identify the causes of my doubts:

  1. My main concern is about the connection of the VINA. According to the "Functional Block Diagrams" of the datasheet it is internally connected to VIN via a resistor. Also the diagrams of the "Typical Application Schematic" of its datasheet and some other resources at TI show schematics with VINA not being connected externally to VIN. However the fact that both have exposed pins and that some non-official schematics on the web show them externally connected together makes me suspicious about if I have to do it or not.
  2. Most of the examples show use cases with fixed Enable and PS/SYNC pins tied to VINA. However, I would like to use them in a different way to take advantage of the Power Saver mode and to use a different case for the enable of the device. As they seem to be liked to the "Power domain" of the VINA instead of the VIN, it makes me doubtful about how to implement them.
  3. Another concern is related to the text of the datasheet on the page 9 on the section "8.4.3 Power-Save Mode and Synchronization" that mentions: "If power-save mode is enabled, the converter stops operating if the average inductor current gets lower than about 100 mA and the output voltage is at or above its nominal value" which does not result clear to me if in this case I won't get a regulated 3.3V voltage.

Now please let me explain what I would like to achieve:

  1. I want to disable the TPS63031 with a lower limit of 3V instead of the 1.8V of the device.
  2. I want to take advantage of the power saver mode offered by the TPS63031. The usual consumption of my circuit is like this:
    1. When it is "Deployed" it performs a continuous a cycle with about 400 mA consumption during 1 to 2 seconds followed with 3 to 20mA consumption during 20 seconds.
    2. When it is not "Deployed", the circuit consumes just about 50uA, which is most of the time.

This is my reasoning so far, which I would like to ask you to correct me if that's the case:

  1. If I connect externally VIN and VINA I'm disabling their internal connection on the TPS63031 (According to its "Functional Block Diagrams"). Then I should not connect them together as I would disable the internal resistor on the device that connects them together.
  2. Implementing a TPS3839G33 (3V voltage monitor) should be done at VIN not VINA. VIN has the voltage of the Power Source I want to supervise and VINA has the voltage of VIN after a resistor (Mentioned on the point 1. above) which is lower.

Regarding the Power Saver mode, I have not find a conclusion. If I permanently tie PS/SYNC to ground I'm not sure if that limit of 100mA mentioned on the datasheet will cause any troubles when my circuit operates well below at 50uA and 2 to 20mA.

This is my current schematic:

Just a final question, I also considered the TPS63051, but the reason I choose the TPS63031 is that the latter has a lower Quiescent current (60uA vs 50uA in similar conditions). However according to http://www.ti.com/lit/an/slyt412/slyt412.pdf being that just one part of the consumption consideration even with idle circuits like mine, none has a significant advantage over the other (In the case of the TPS63051 I won't choose to implement the Power Good whose pull up resistor could make a difference). I'm I right? Or does one has a better advantage over the other?

I appreciate any light on this.

Thank you!

↧

Buck boost converter for Solar pannel

May 25, 2019, 10:55 pm
$
0
0

Hi team

Please advice buck boost converter to keep constant voltage for following requirements

Output Constant Voltage 12v

Current 10A

Input voltage 12v and 90A battery

Practically I have seen that battery voltage 14.2v with load 

Thanks in advanced 

↧

TPS61085A-Q1: different between TPS61029DRCR vs TPS61085ATDGKRQ1

May 25, 2019, 11:49 pm
$
0
0

Part Number:TPS61085A-Q1

Hello team,

I am used TPS61029 in my last design and we want to move to TPS61085 but I'm worried about EMC problems, I Know that from EMC aspect TPS61029DRCR is OK.

Can you advise with the different between TPS61029DRCR vs TPS61085ATDGKRQ1 from:

  • EMI emission radiation?
  • Output voltage ripple value?

my step up requirements are Vin=3vmin, 4.75vmax | Vout=5v (up to 0.7A), which device should be better for my application.

Thanks in advance.

Regards,

Shai   

↧
Viewing all 35901 articles
Browse latest View live
Search