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TPS61194: How to calculate the power dissipation?

October 24, 2019, 12:49 am
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Part Number: TPS61194

Hi 

Would you share How to calculate the power dissipation? 

In my application,

- there are 4 strings,

- each string has 9 LEDs (VF = 3.7V x 9 )

- Vin 9 ~ 16 V

- 90 mA per channel / string  

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LM20333: Undervoltage Comparator

October 24, 2019, 12:50 am
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Part Number: LM20333

Dear, Sir.

My customer is looking for the device to protect against abnormal FB voltage due to

external FB resistor divider open or short.

LM20333 looks have the internal undervoltage comparator inside of FB path.

Could you explain the behavior about the undervoltage protection if it had certainly.

Is it similar as OVP? Please give your advice.

Best Regards,

H. Sakai

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BQ2000： BQ2000充电电流问题

October 24, 2019, 12:55 am
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Part Number: BQ2000

您好！

  关于BQ2000我有个问题想向您请教！规格书内标注的SNS管脚电压为50mV正负误差在10mV，但实际批量上机后，发现部分的电压只有27mV,不满足误差范围内，导致充电电流偏小。不良率大致在1.5%。

有关规格书所提到的滞后电压是否与此有关!

期待您的回复，谢谢！

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BQ35100: Calibration problem

October 24, 2019, 1:01 am
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Part Number: BQ35100

Hi :

I am using the TI meter. I have two questions for you. Please help me answer them.Thank you.

I used TI BQ35100, I saw the description of BQ35100EVM, calibrating CC Offset,Board Offset must be 0 Load,Currect=0, actually our operation is to design BQ35100 into our product PCB, how to achieve calibrating CC Offset,Board Offset is 0 Load?

2.Battery Management Studio has a parameter file of various batteries certified by TI. I found the Battery we used (Chemistry) and clicked OK. However, the Battery parameters in Gas Gauging have not changed.What does Chemistry do?What does the battery parameter library do?Also please help answer, thank you.

BR

Ren

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BQ24103: BQ24103 when battery charge full the LED flash

October 24, 2019, 1:07 am
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Part Number: BQ24103

HI

when battery charge full the battery over charged and the LED become flash.

Attached BQ24103 schematic and BAT waveform.

Please help check.

Thanks

Star

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TPS2660: LED connected with FLT pin turn on a moment during power on/off

October 24, 2019, 1:08 am
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Part Number: TPS2660

Hello experts,

I got question from customer.
My customer plan to use TPS26601 for their system.
They plan to indicate error with LED connected with FLT pin, when TPS26601 detect error (Over current, over VPORR).
But, LED turn on a moment during power on/off timing. They don’t want to turn on LED during power on/off timing.
TPS26601 may detect inrush current during power on timing. Or, this IC may detect V(PORR) error during power off timing.
Do you have any idea to avoid this phenomenon which LED turn a moment on during power on/off?
LED cirsuit is as below;
FLT pin -> resistor (15kohm) -> chip LED
IN pin is connected with UVLO pin directly.
OVP pin and RTN pin are connected directly, also ILIM pin is connected through RLIM with this line.
Thanks and best regards,
Ryo Akashi
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TPS61071-Q1: How does TPS61071 do OCP and OTP ?

October 24, 2019, 1:18 am
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Part Number: TPS61071-Q1

Hi 

How does TPS61071 do OCP and OTP ?

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TPS92610-Q1: About LEDs configuration

October 24, 2019, 1:21 am
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Part Number: TPS92610-Q1

Hi team,

A cusotmer asks some questions about TPS92610-Q1.

-. TPS92610-Q1 can be used for TFT LCD backlight?

-. For below configuration with TFT LCD(800 x 90), can TPS92610-Q1 support fine dimming control without brighteness issue and etc?

 

Thanks,

Sam Lee

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TPS54308: Do you have any equation to calculate output capacitor ESR like equation6 on page 23 of LMR33630 datasheet?

October 24, 2019, 1:25 am
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Part Number: TPS54308

 Hello guys,

 One of my customers is designing their own board using TPS54308 for their new products.

 They want to get any equation to calculate output capacitor ESR like equation6 on page 23 of LMR33630 datasheet?

 Do you have it?

 Your reply would be much appreciated.

 Best regards,

 Kazuya.

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UCC21750: CBLK value for DESAT

October 24, 2019, 1:32 am
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Part Number: UCC21750

Hi team,

I have question about the DESAT solution. According to the EVM of UCC2732, the CBLK is 27pF. 

- how do you calculate this ?

- I feel very small capacitor, is it no problem about surge even such a small capacitor? 

Thanks,

Uchihara

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LM7800: LM7805 data sheet discrepancies?

October 24, 2019, 1:35 am
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Part Number: LM7800

Hello Team,

I noticed some discrepancies when trying to calculate the power dissipation. Which thermal resistance do I need to use for TO-220 (and SOT-223), please?

The text tells me 54°C/W and the Thermal Information Table 6.4 shows 23.9°C...

Maybe I missunderstand something?

Thanks and Best Regards,

Hans

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TPS65381A-Q1: About the Diagnostic states.

October 24, 2019, 1:52 am
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Part Number: TPS65381A-Q1

Hi team.

I'd like to know bellow my customer's questions.

1, DIAGNOSTIC state time-out

    According to the data sheet, this time is 512ms(typ).

    Do you have a minimum value?

    Is there a way to extend it?

2, When transitioning from Diagnostic state to Active, 

　Is this the correct register to set?

    SAFETY_ERR_STAT Register : Reset ⇒ DIAG_EXIT_MASK : 0⇒ DIAG_EXIT : 1

　Should we separate ''DIAG_EXIT_MASK''from ''DIAG_EXIT''?

　Is it okay to put them together in one register?

3, Is it possible to operate only in the diagnostic mode when CFG_LOCK : 1 ?

   When the CFG_LOCK is 1, can we write DIAG_EXIT?

Sincerely.

Kengo.

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LM5146-Q1: Internal regulator stability

October 24, 2019, 1:54 am
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Part Number: LM5146-Q1

Hi,

In the datasheet of LM5146-Q1, there is a line mentioning "Connect a ceramic decoupling capacitor between 1 μF and 5 μF from VCC to AGND for stability".

What exactly does the stability of the LDO mean? 

I understand that they serve the purpose of high frequency currents thereby decoupling the supply from those transients. What is the stability concern?

Can you please explain?

Regards,

Siri.

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TPS25927: UL document for TPS25927

October 24, 2019, 2:07 am
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Part Number: TPS25927

Dears

could you provide UL-62368, UL-60950 document for me, thanks

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TPS53688RSBR device datasheet request

October 24, 2019, 2:10 am
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Hello,

Let me reopen request for device datasheet of TPS53688RSBR again. Last year I have asked, but the e-mail contact I got seems to be not active. 

So lets continue in this case.

Best regards,

Frantisek

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LM73605-Q1: When the input voltage goes to lower than the output voltage, will LM73605-Q1 have any problem?

October 24, 2019, 2:16 am
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UCC28780: Question about EXCEL design Calculator of the UCC28780

October 24, 2019, 2:32 am
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Part Number: UCC28780

Hi,

I'm working on designing an Active Clamp Flyback using the UCC28780 for a 35W power supply 115Vac/400Hz input for 30Vdc output.

I base the design on the excel calculator, but i'm struggling on understanding some INPUTs.

  1. Knowing that my power supply should handle a variation of input voltage of 97V - 165Vrms, i dont understand what to insert in the bronw out/in Voltage (C17/18 in the excel), and the input burst voltage (C20).
  2. Based on what i should choose the minimum switching frequency ?
  3. In the Transformer Parameter, by fixing the primary to secondary Turns ratio as recommanded, how to choose the optimal Primary Turns ?

Thank you very much.

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LMZ31710: Mechanical Reliability Related to Temperature Change

October 24, 2019, 2:43 am
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Part Number: LMZ31710

Hello team,

My customer did an X-ray inspection of LMZ31710.
The internal coil appeared to be mounted on the top surface of the IC.
The shape of the case is not rectangular, and looks a little bit special.
My customer cares about the risk of mold breakage due to the coil expansion caused by temperature change.
Do you have any collateral to convince my customer?

Regards,

Itoh

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CSD97395Q4M: Whether CSD97395Q4M falls under REACH

October 24, 2019, 2:46 am
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Part Number: CSD97395Q4M

Dear all,

I would like to ask a question.

Our customer asks if CSD97395Q4M falls under REACH.

If you check the web page of the product, you will see Pb free (RoHS Exempt).

I have heard that RoHS regulations do not apply even if lead is contained inside.

So please let me know if CSD97395Q4M falls under REACH.

If so, I need to offer them a product with the same performance that does not fall under REACH.

Best Regards,

Y.Ottey

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TPS61169: Minimum PWM On-Time Requirement

October 24, 2019, 2:52 am
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Part Number: TPS61169

Hi,

According to "Simple Backlight Driver Dimming Performance", there is below description.

"Because the TPS61169 does not have 1-wire control, at lower input voltages the device does not stop outputting current unless the PWM signal is 0 V. Any pulse width greater than 50 ns at any frequency within the range of each chip, respectively, outputs a stable and steady current."

http://www.ti.com/lit/an/snva769/snva769.pdf

However, there is the sample which does not satisfy with this as attached.

(Please visit the site to view this file)

Is above description wrong?

Best Regards,

Kuramochi 

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