Part Number: PMLKBUCKEVM
Dear expert:
I want to calculate buck input current ripple. How can choose from formula(5) and formula(6)? I don't know how to judge high and low capacitance,can you kindly teach me please?
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PMLKBUCKEVM: input current ripple
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TPS25921A: Precision Power Limiting Solution TIDA-00331
Part Number: TPS25921A
Team,
I have some questions about following reference design http://www.ti.com/tool/TIDA-00331
What’s the working condition of Q1? How to determine the value of R7, R8 and R9? Could you please provide the calculation process?
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TPS544B25: Recommend connection for programming board
Part Number: TPS544B25
Hello E2E,
Could you please provide the recommend circuit for programming board use?
BR,
Jason
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BQ76PL455A-Q1：BQ76PL455A-Q1 External power supply, shutdown mode, reverse power supply, will it damage the chip?
Part Number: BQ76PL455A-Q1
BQ76PL455A-Q1 If the external power supply is used, in the shutdown mode, the power of the VIO and GPIO is not turned off, and the reverse power supply occurs. In this case, will the chip be damaged?
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TPS61040: TPS61040 - definition of the soft start feature
Part Number: TPS61040
Hi there,
I want to use the TPS61040 as a backlight driver (schematic as datasheet figure 21). During start-up there is a delay of 250us between setting the EN-pin to high and the switching of the power-MOSFET (SW-pin).
How are the 250us defined? What is the maximum delay I can expect the SW-pin to start switching?
As a backlight frequency I use 200Hz. This means that I always loose 5% of the brightness and has unwanted influence on the linearity of the brightness. Is there a way to shorten this start-up delay and also shorten the soft start?
Thanks for all feedback in advance.
Kind regards,
David
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LMR14020: resistor value of EN pin check
Part Number: LMR14020
Hi team
Here is the design I develop for monitoring the MCU VCC. I use TPS3702 to monitor the MCU VCC and shunt down the LMR14020 by connecting the OV pin to EN pin when the MCU VCC is too large.
1. so here I want you to help check the schematic.
2. Especially whether the Rpu(10k) is appropriate, because the Rpu used in the reference design of LMR14020 is usually hundreds of K. I don't know whether the Rpu(10k) I selected is appropriate, and how to find the maximum input current of the EN pin of LMR14020 from datasheet.
Best Regards
Wesley Huang
Wesley Huang@ti.com
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UCD90120A: PMbus pullup resistors
Part Number: UCD90120A
The datasheet states that pullups resistors are required, and the evaluation kit indicates selectable resistors for 2k2, 1k or FLOATING, but on the USB transceiver side, while the UCD part has actual no series or pullup resistors on that sheet.
The documentation references PMbus and/or SMbus, but in between all those specifications and TI information, the pullup resistors could be as low as 680 ohm. I would expect that a minimum that 4k7 resistors would have been specified. What is the actual requirement here on the value of pullup required?
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TPS3702: checking schematic of monitoring TMS320F28062
Part Number: TPS3702
Hi team
I use TPS3702 to monitor the VCC of TMS320F28062 . I connect the UV to MCU RST pin to reset the MCU when the MCU VCC is under 2.9V and connect the OV to LMR14020 EN pin and the gate of NMOS to shunt down the DCDC and SN74HC244 when the MCU VCC is over 3.6V .
1. Could you please help me to check the schematic?
2. helping me check if there is any timing problem of this design
3. helping me check if the Rpu value is appropriate
Best regards
Wesley Huang
welsey-huang @ti.com
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Looking for a Power load switches
Hi,
In my application, I need to switch ON and OFF Power(3.3V at 1A max-3.3W) to another IC through GPIO of the controller(3.3v), I initially had chosen TPS22919 which has 1.5A continuous current. But when I calculated the Max Power dissipation as per the datasheet is given in 11.3 Thermal Considerations which has a max P dissipation of 0.5W.
Looking for a Power load switch for this application.
Even the TPS22810 says max Current of 3A and max P Dissipation is about 1.6W at Ta-23C.
(Is my calculation wrong?)
Thanks.
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TPS92513HV: Soft start TPS92513HV
Part Number: TPS92513HV
Hello,
We would like to use the TPS92513HV driver with a soft start function (for example 300-500ms).
I cannot find anything about soft start in the datasheet. Is there a way to use the PDIM of IADJ input to achieve this behavior?
Thanks in advance, Cees
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UCC28070: The AC current will be unstable during very short time.
Part Number: UCC28070
In the evaluation of this device, when the AC input voltage is changing, the AC current will be unstable during very short time.
This behavior is due to that the AC voltage is reaching to threshold of the linear multiplier as showed on datasheet 7.3.10.
However, even though the AC voltage is held on this point, the AC current will be stable soon.
Can you respond to the following questions?
1. Why the AC current will be stable soon in this case? Is this due to feedback?
2. Is there a possibility to keep the AC current will unstable?
3. When the AC current will be unstable, is there any problem for the PFC working? (for example, the power factor will be bad)
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WEBENCH® Tools/LM5140-Q1: LM5140-Q1
Part Number: LM5140-Q1
Tool/software: WEBENCH® Design Tools
Hi,
Would you please provide the average pspice model of LM5140-Q1, which I can't find on TI's Web.
Beside, I wonder whether the value and ESR of output capacitor will affect the loop response such as phase margin.
Would you please provide some docs to analyze the effects of value and ESR of output capacitor?
Thanks anyway!
Kevin Shen
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LP5907: Spur at Cold Temperature
Part Number: LP5907
Hi Expert,
We observe ~35dBc spur at +/-4Mhz offset under -35degC. We tried to touch the chip with hand, the spurs would disappear. In addition, we also found if adding another Cout=4.7uF, the spur would disappear too.
Could you please clarify is it related to the temperature or output cap in terms of stability?
Thanks.
Allan
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BQ34Z100-G1: BQ34Z100-G1, Hall sensor
Part Number: BQ34Z100-G1
I would like to know, if it is possible to measure current with bq34z100-G1 IC using hall sensor instead of shunt resisitor for high current applications.
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BQ24725A: Power management forum
Part Number: BQ24725A
Hi,
- Can this IC be used for a discharge current of 10A battery management system?
- Does this IC take care of battery discharge current or a separate circuit need to be accommodated for this purpose?
Thank-you
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dual output power supply non isolated
Hi,
My motor drive customer is revisiting ACDC power supply that are 20 years old right now.
They are looking for dual output supply non -isolated input ±18 V ±5%, output ±15 V, 0,1 A.
Any ideas?
Many Thanks,
Antonio
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TPS568230: Question about TPS51396
Part Number: TPS568230
Team,
my customer using TPS51396 for 4V(5A) and 3V(4A) circuit like below.
Key questions : Is there have any method to simulation phase margin of TPS51396?
question : could you help to get phase margin simulation results ?
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BQ24773: BQ24773 can work without battery with load on default setting ..?
Part Number: BQ24773
Hello TI,
1. Testing on own design PCB which is design as per the TI reference Design & Guidelines
2. Use 5V/ 2A adapter with BQ24773 for testing
3. design for 1 cell(2200mA) charging
There is some question about the BQ24773 working,
1. BQ24773 can work without battery with load on default setting(Without configuration) for initial system ON..?
2. BQ24773 can work with load on Default setting if yes, what is the minimum load handle the system ..?
we are design the system for specific application, please clear the below mention points
1. BQ24773 can work standalone..?
2. BQ24773 can work with or without battery ..?
3. BQ24773 can able to work like UPS system ..?
please refer the thread for more details of design 
Thanks and Regards,
Rahul Surawase
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SNVA538: Question about result
Hello TI,
I have a short question about the SNVA538:
At page 10, the result of the mentioned optimization of the two stage filter is shown as:
L1 = L/2
L2 = 7*L1
Ld = L2/2
C2 = 4*C1
Rd = sqrt(L1/(4*C1))
Further below, at page 19, I found a example for this filter. But the formulas used for this are different:
L1 = L/4
C1 = C/4
L2 = 7*L1
C2 = 4*C1
Rd = sqrt(L1/C2) ---> Rd = sqrt(L/(4*C1))
Ld = L1/8 ---> Ld = (L2/7)/8 = L2 / 56
For me, there main difference is the big difference in the calculation of Ld by a factor of 28.
The difference in choosing of L1 is in my opinion not that serious, as it does not change the ratios of the components.
Could you please explain the differences i beetween these formulas? I would try to perform the mentioned optimization by myself, but the assumtions used for it are not stated in this paper (or at least I did not recognized them)
Thank you a lot,
Dominik Lorenz
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BQ76920: ADC_EN = 0?
Part Number: BQ76920
Hello;
I've been developing with your bq76920EVM and initially upgraded the F/W to -R2. My host application could successfully read cell volts, temperature, current, faults, etc.
But then, all the sudden the AFE stopped sending voltage data. It continues to send CC values every 250ms, but not volts or temperature. Sending for AFEConfig (0x0059) shows that SYS_CTRL1 (0x04) = 0x00, which I believe indicates that the ADC is disabled. Then I asked for AFEStatus (0x0058) which returns 0x02, apparently flagging a SCD, but the AOLD and ASCD thresholds are set to 0x7F and 0x87 respectively, and the voltage at SRN is <50mV.
I then attempted to use bqStudio to find the problem, but it now no longer recognizes the board? I can find no 78350 command that reenables the AFE's ADC..POR does nothing. The -R2 .bqz file is still in the proper location, and I'm concerned that if I "proceed at my own risk" and try connecting anyway, the device may be permanently clobbered.
Thanks for any help.
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