About Andrew Lohmann

Andrew Lohmann · 2021-03-30

Will IC such as L6924U operate with AC ripple on the power input? That is as if the power input were rectified AC with no reservoir capacitor?I posted this before but can not find the post now? Sorry for duplicating the question if it is duplicated...

Andrew Lohmann · 2021-03-25

Will all or any battery charger ICs such as L6924U operate properly with rectified AC input?The rough circuit below is of a bicycle dynamo that delivers 300mA-500mA of varying AC frequency and current ripple will this prevent the charger controller f...

Andrew Lohmann · 2021-03-03

I would like to use a SMP controller such as L6726 or other as a boost regulator. That is use the high side output (pin PHASE) connected to 0V and my boost transistor. I would use the low side driver to drive a MOSFET as a synchronous rectifier Is ...

Andrew Lohmann · 2021-03-02

Can either A6727 or L6726A buck controllers be used as a boost controllers by connected the high side driver (Phase) to 0V to drive my power transistor?Alternatively do you have spice models that I could use on LTspice or Tina-TI for example. Please ...

Andrew Lohmann · 2020-12-13

Microcontroller may be; STM32L0 or L4Required; 5% worst case over -5 to 50'CThe microcontrollers are quoted 1% accurate at 25'C but I can not find how accurate they over the ICs temperature range. I want to avoid trimming or fitting a crystal.The ...

Andrew Lohmann · 2021-07-20

Thanks for the explanation on the smt part.

Andrew Lohmann · 2021-07-20

Those unconnected guard track ends are not ideal but I don't see a problem with them and they may be a good thing. A solid 0V plane under the crystal and the 0V the first inner layer below it should have been okay comparing with what Franck has done...

Andrew Lohmann · 2021-06-10

If I understand, the oscillator comes out as a pair, goes below then comes back to the top, then the pair terminates at the capacitors then tracks a little more to the crystal. No doubt adding PCB capacitance, which you adjust for by reducing the val...

Andrew Lohmann · 2021-04-06

Thanks possibly the circuit is not visible but it does have voltage limiting that you advise. I suspect the your answer will be true of many similar ICs including others made by other manufacturers but the detail is not clear.

Andrew Lohmann · 2021-03-22

It sound like your PCB is more noisy generally. I would not recommend separate ground planes they can ring but you may be able to mitigate that by putting a bead inductor in series with 0V crystal common point. that is a low Q inductor.

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Battery charger ICs run from rectified AC input

Will all or any battery charger ICs operate properly with rectified AC input?

SMP controller such as L6726 or other as a boost regulator.

Using A6727 or L6726A buck controllers as a boost controllers

international oscillator accuracy over temperature range

Re: STM32H7xx RTC accuracy problems

Re: STM32H7xx RTC accuracy problems

Re: STM32H7xx RTC accuracy problems

Re: Will all or any battery charger ICs operate properly with rectified AC input?

Re: STM32H7xx RTC accuracy problems