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Type: Posts; User: KlausST

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  1. Closed: Re: IGBT Short Circuit Detection using Current sensing

    Hi,


    An OPAMP is an amplifier, it has an analog output.
    To detect "= logic output" you should use a comparator.
    (Although OPAMP and comparator share the same schematic symbol, they are...
  2. Closed: Re: Real use of left and right alignment in ADC

    Hi,

    Some think in LSBs. They like to use right aligned ADC values.

    I like to think in "full scale" ...i like left aligned.

    Some ADCs are available in 12, 14, 16 bit versions. If you use left...
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    Closed: Re: Portable headphone amp w. batteries

    Hi,

    There are class D headphone amplifiers. They will consume less power, which increases battery lifetime.

    Klaus
  4. Closed: Re: Runtime of clock using alkaline D cells instead of AA batteries

    Hi,

    Please use correct units.
    * capacity is 15,000 Mah. --> 15,000 mAh
    * device using 120 Mah --> 120 mA (without "h")
    * and so on..


    How do you come to 80 h?
    My calculator says this is...
  5. Closed: Re: Lock -in Amplifier/ tuned amplifier in DSP

    Hi,

    Digital filters are relatively simple and precise.

    Maybe the bigger problem is the ADConversion.
    The correct sampling rate, resolution and correct precision as well timing and amplitude.
    ...
  6. Closed: Re: IGBT Short Circuit Detection using Current sensing

    Hi,

    Is all the isolation really necessary?
    It's more fast without optocouplers.

    And it's more fast when you don't feed the overcurrent signal through the microcontroller.

    Klaus
  7. Closed: Re: Transimpedance amp for DC only (bandwidth limited)

    Hi,


    But the voltage across the diods should be only a couple of millivolts.

    Klaus
  8. Closed: Re: Transimpedance amp for DC only (bandwidth limited)

    Hi,


    No.
    Only the leakage of the capacitor may cause problems..
    Use high quality polystyrene, if possible.


    * The diodes are for "protection" only, not for rectifying..
    * use "low leakage"...
  9. Replies
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    Closed: Re: Cheap Mains harmonics tester

    Hi

    Please confirm that you talk about current harmonics (and not voltage harmonics).
    (The difference is, that with "current" you simply can focus on your DUT, while with voltage you need to do...
  10. Closed: Re: Operational amplifier driving capability test

    Hi,



    I don't expect a 5% voltage drop on a non saturated, feedbacked OPAMP.

    Thus I expect the test setup was either in "non feedbacked" condition, or the Opamp output was in "saturated"...
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    Closed: Re: Li-ion Charging indicator

    Hi,

    You already have recognized one important thing:
    The voltage across the battery does not tell much about charging status.

    Thus there are dedicated charging status ICs, they mainly are...
  12. Closed: Re: Operational amplifier driving capability test

    Hi,

    What happens on overcurrent?
    Is the output weak, an thus the output voltage drops?
    Or is the ouput strong and the Opamp overheats?

    Klaus
  13. Closed: Re: li-ion voltage reducer to 3volt - help needed

    Hi,

    The problem with this shunt voltage regulator is, that it draws a lot of current.
    Li-ion voltage is above 3.6V even when it is discharged to 10% charge.
    This means about 5mA zener current....
  14. Closed: Re: Higher Current Consumption than expected with AFE and embedded Flash

    Hi,

    As already said (and if not otherwise mentioned): close to VCC or close to GND.

    It is written in the datasheet, and I assume the IC manufacturers provide additional information about "low...
  15. Closed: Re: Higher Current Consumption than expected with AFE and embedded Flash

    Hi,

    Please confirm that at any time no pin is left floating, neither a used pin nor an unused pin.

    Usually input pins where the voltage level is not close to VCC or GND may cause increased...
  16. Replies
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    243

    Closed: Re: Li-ion Battery charger need help

    Hi,

    May I ask why you didn't read the datasheet?

    It is no Li-Ion, it specifies the charging method, it specifies the charging current, which is not 1C...

    Klaus
  17. Replies
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    243

    Closed: Re: Li-ion Battery charger need help

    Hi,

    What exactly does the datasheet say? 1C is typical or recommended charge current, or maximum charge current?
    (Why don't you post a link to the datasheet?)

    Doesn't the manufacturer provide...
  18. Closed: Re: How can I tell if my laptop screen is LED or LCD?

    Hi,

    There are laptops with OLED display.

    Thus I recommend to look into the operating manual of the laptop or consult the manufacturer's internet pages.

    Klaus
  19. Closed: Re: li-ion voltage reducer to 3volt - help needed

    Hi,

    There are linear LDOs.
    And there are switch mode step down converters, also called buck converters.

    All have their benefits and drawbacks.

    But to decide which one to choose, you need to...
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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    Hi,

    There are electronic devices called capacitors.
    Do you know them?

    Klaus

    Added:
    Your schematic violates general rules how to use gate drivers as well as IGBTs.
    The same applies for the...
  21. Replies
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    361

    Closed: Re: Protecting SMPS against mains transients.

    Hi,

    Basically every overvoltage protection includes:
    * a serially connected device to limit the current (even wiring)
    * a parallel connected device to limit the voltage
    For sensitive devices...
  22. Closed: Re: Is it possible to make an IGBT to work at duty cycles up to 100%?

    Hi,

    I wonder why you still ask the same vague question.
    It is already answered that there is no problem in continously operating an IGBT. There is nothing special to take care of.
    All...
  23. Replies
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    Closed: Re: Bldc Motor controller Mosfet Circuit

    Hi,
    I can not remember to have seen this circuits before...and I've seen a couple BLDC circuits.

    Then show us.
    If it's in "all" ... then I expect it to be in the application notes, too...and I...
  24. Closed: Re: PCB layout design consideration for BLDC controller

    Hi,

    Every Mosfet manufacturer and every gate driver IC manufacturer provides application notes and design notes. They are free. Use them.

    Klaus
  25. Replies
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    Closed: Re: I2C not working properly

    Hi,

    Maybe a dumb question:
    When your I2C slave has no internal clock, then how can it generate 300ns (or more) delays?

    I2C_START condition: SDA_falling @ SCL_HIGH
    I2C_STOP condition:...
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