Hi!
I am following the steps in slva633 and using the input data from this document:
Vin = 5V, Vout = 18V, Iout = 3A, L = 20uH, Fsw = 200kHz, Cout = 1480uF, Cesr = 8mOhm
D = (Vout - Vin)/Vout = (18 - 5) / 18 = 0.72(2)
(5) Frhpz = Rload (1-D)^2 / (2 pi L) = 18V/3A * (1 - 0.722)^2 / (2 pi * 20uH) = 3684 Hz
(2) Fres = 1 / (2 pi sqrt(Cout * L / (1-D)^2)) = 1/(2 pi sqrt(1480uF * 20uH / (1 - 0.722)^2)) = 257 Hz
Fesr = 1 / (2 pi Cout Cesr) = 1 / (2 pi 1480uF * 8mOhm) = 13400 Hz
6. The crossover frequency should be less than about one-tenth the switching frequency.
Fcross1 < 200 kHz / 10 = 20 kHz
7. The crossover frequency should be less than about one-fifth the RHP zero frequency.
Fcross2 < Frhpz / 5 = 3684 Hz / 5 = 737 Hz
8. The crossover frequency should be at least twice the resonant frequency.
Fcross3 > 2 * Fres = 2 * 257 Hz = 514 Hz
Min(20 kHz, 737 Hz) > Fcross > 514 Hz
--- What should we do if (Fres * 2) > Min(20 kHz, 737 Hz)?
Should we increase the Cout value or should we use different equations?
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Voltage-Mode Boost Compensation, SLVA633
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UCC28780EVM-002: 019‐8916‐00R
Part Number: UCC28780EVM-002
Hi
I want ask component that part number is 019‐8916‐00R, is there has the core datasheet? Or is there anyway to find the Ae(effective area) of the core. Attached file is the component datasheet.(Please visit the site to view this file)
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TPS7B7702-Q1: The device is broken when doing the short circuit test
Part Number: TPS7B7702-Q1
Dear team,
Today my customer did the short circuit, but the device is broken. Then the customer measured the resistance between each pin and ground, and finally found that the output pin is shorted to ground.
Their short circuit test operation is as follows(this test method is required by the OEM)，
Except for the ground and output pins, all pins are properly connected. The GND pin is disconnected with the ground, and then the output pin is connected to the GND pin. They tested 3 devices, and all are broken. Could you please help analyze this phenomenon?
And my customer thinks maybe this is related to the diode as below, and they wants to ask for the specs of this diode(Maximum Repetitive Peak Reverse Voltage, Peak Forward Voltage, Average Output Rectitifed Current, Peak One Cycle Surge Forward Current, Volt-ampere characteristic curve). Could you please provide these information?
In addition, the schematic and layout is as below,
Thanks & Best Regards,
Sherry
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BQ40Z50-R3-DEVICE-FW: BQ40Z50-R3
Part Number: BQ40Z50-R3-DEVICE-FW
Hi
Can you please explain the difference between these parameters. These parameters I am listing out from the BQ40Z50 log file.
voltage = ? current = ? vBAT = battery voltage, vPACK = pack voltage, I understand vBAT and vPACK, but what is voltage and current?
FltRemQ = ? , FltFullChgQ = ?, TrueRemQ = ? , TrueFullChgQ = ? I understand Q is capacity.
SOH_FC_Q = ? I understand SOH = state of health, but what is SOH_FC_Q
I am attaching the log file for the reference.
(Please visit the site to view this file)
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BQ24171: External source instead of Vref
Part Number: BQ24171
Hello,
IC: BQ24171RGYT
Battery: 3P2S pack of 18650s
Thermistor: the pack has a 10k NTC thermistor in it which I have connected to TS as described in the BQ24171RGYT datasheet.
Ext power: 12V wall plug to power the charger
Extra TS connection: TS is also connected to ADC of an MCU so MCU can read battery temperature and turn on a fan as needed.
Problem: when 12V charger cable not plugged in, Vref = 0V. When Vref = 0V, TS circuit is off and MCU can't read thermistor value.
Proposed solution: replace Vref with an external 3.3V supply that can be controlled by MCU.
Question 1: does proposed solution sound reasonable?
Question 2: how stable does 3.3V supply need to be? Is 3.3V from main system buck regulator reasonable or should I add a dedicated LDO?
Question 3: should I replace all Vref with the external 3.3V supply or only TS. I only need it for TS.
Question 4: do you have any other solutions to consider?
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TPS63031: Average Current Consumption when TPS63031 is enabled ON
Part Number: TPS63031
Hello,
What is the average current consumption of the TPS63031 when the EN pin goes high? Is it higher than the RP604K331A by Ricoh Electronics?
Thank you,
Kyle Wisbrock
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LM76202-Q1: Cin and Cout
Part Number: LM76202-Q1
Hi,
We want to use LM76202-Q1 as the reverse current blocking socket. And I want to know the function of Cin and Cout and how to choose their values.
Thanks&Best Regards,
Wenxiu
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WEBENCH® Tools/TPS54360B: Power dissipation view in new tool
Part Number: TPS54360B
Tool/software: WEBENCH® Design Tools
Where is the power dissipation tool located in the new webench?
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LMZ34202: LMZ34202RVQT Step Model Request
Part Number: LMZ34202
Hello,
I need a step model for:
LMZ34202RVQT
Thanks!
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LM117HV: Regulator Overheating when no load with little change in voltage
Part Number: LM117HV
I am designing a circuit where the voltage is regulated from 15V to 9.15V. However, it overheats when there is no load for the regulator. And, even when I set the input close to the desired output input set at 13V. The regulator is overheating. R1 is set at around 100 ohms while R2 is set at 15 ohms. I don't have much experience with this and would appreciate it if someone can help explain what is happening. This is for LM117H
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BQ76920EVM: Device won't boot/work with bqStudio
Part Number: BQ76920EVM
Hi, we purchased four BQ76920EVM devices, but one of them won't boot/work with bqStudio.
Are there any troubleshooting steps that you suggest we should try.
Thanks,
Justin
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TPS3898: high voltage part
Part Number: TPS3898
Hello,
the TPS3898 is rated for 7V max. is there an equivalent part with active low enable and active low output which is rated for atleast 10V or more? it will be great if the part has adjustable in-out delay as well.
Thank you,
Gaurav
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TPS61120: Minimum Switching Current 200 mA
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Boost device recommendation
Hi,
I'm looking for a 5V input, 8.7V/1A output DCDC for the external battery charger circuit.
Cost will be the main concern, and with less external component would be better.
Could you please help to recommend some parts for this?
Thanks.
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BQ24193: bq24193 battery management issue
Part Number: BQ24193
Hello,
We had a problem with bq24193 BMS IC . bq24193 supports input voltage range of 3.9V to 17V . But this IC is not working for 15.1V input with 1A load . At this input the IC is damaging.how to solve this issue?
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LM2623: Correct C3 for duty cycle of 86%
Part Number: LM2623
Dear experts,
I want to boost from Vin (2.5V to 1.7V) to Vout(10V) with LM2623A. The output doesn't need to be perfectly stable (so it may exhibit ripple). Iout should be as much as possible. Therefore I'd like to use the LM2623A with high switching frequency and high duty cycle (86% - 88%).
I planned to use R3 = 50k to 75k. The inductor was planned to be 10µH. In which range should I test C3? What's your proposal?
Thank you.
Matthias
PS: I already did a design with TPS61022 and subsequent voltage doubler, as proposed, which is working. But there should be a second version, which can be hand-soldered more easily. And if I out is a lot lower compared to TPS61022, it doesn't matter.
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UC3845: Current sens resistor calculation when extra fading voltage from Vref pin
Part Number: UC3845
Hi;
I am making Constant voltage 5VDC flyback based power supply using UC3845. I have read TI datasheet .
As per page number-25 Current sensing network design Equation number : 22.
Generally we can calculate Rcs value from maximum peak primary current, as we know when drop across Rcs higher than 1V it terminate the gate output voltage.
But according to datasheet we can reduce current sens losses by injecting extra voltage to Isens pin using Vref and voltage divider network.
I cant understand how it work? How
VOFFSET = (RCSF × VREF) / (RCSF + RP) use and then how find Rcs value from it?
Sometimes in many design I have seen that one transistor connected with Vref pin and base pin connected with Ct (RT-CT network) . Really it is difficult to understand.
Can you please provide simplification ? with detail example and explanation ?
Attached one file : in this case Ipk = 414 mA . (This simmulator design from TI web-
bench online)
Looking for your support
Thanks :
Jaydeep Shah
radhey04ec@gmail.com
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TPS543C20: TPS543C20 Sequence-EN and PGD
Part Number: TPS543C20
This is my test of power-off sequence on TPS543C20EVMs. 1 channel is EN of Module-A, 2 channel is PGD of Module-A, 3 channel is EN of Module-B, 4 channel is PGD of Module-B. When the EN of the module-A goes low, the PGD also goes low after a delay. Next, the EN of the module-B becomes a low level, and the PGD also becomes a low level after a delay. Time between EN disable of module-A and PGD response of module-B is 4.62us. However, in the datasheet, the delay for PGOOD coming out is 2us.
Test Conditions: 12V Vin, no load.
In my test, the output voltage needs more than 1 second to go outside the 12% of the target value under no load.
If the output voltage goes outside of ±12% of the target value, the power good signal becomes low after an internal delay. EN controls PGD when there is no load?
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CCS/TPS659039-Q1: About PMIC self-diagnosis function
Part Number: TPS659039-Q1
Tool/software: Code Composer Studio
Hi，
If the SOC causes an overload or abnormality in one of the PMIC channels, then the SOC is reset and the INT interrupt of the PMIC is not collected in time.
After the SOC restarts normally, can the SOC read the last fault of the PMIC?
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LMR14030-Q1: LMR14030-q1 with schottky diode
Part Number: LMR14030-Q1
Hello, everyone.
I am Gabriel An, and I am planning to use LMR14030-q1 for the power, and need schottky diode for low side switch.
I looked at the LMR14030EVM guide and "DIODE Incorporated PDS560-13" schottky diode is used in the EVM guide, and I want to use TI schottky diode.
Can I use TI schottky diode UC1611 and UC2310 with LMR14030-q1 and LMR14050-q1?
Thank you
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