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  • Teratron commented on robosap's instructable Power Supply LM3171 year ago
    Power Supply LM317

    Interesting way to control the LM317! I think your R1 feedback resistor on you circuit diagram should go to Vout though. I would also add some capacitance on the output for stability and low ripple.☺

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  • Salvaging Rechargeables for Projects

    Hi, there are several online from China like these:https://www.banggood.com/Original-ZHIYU-60W-110W-9...https://www.banggood.com/ZB2L3-Battery-Capacity-Te...Mine is similiar this this one:http://jayakody2000lk.blogspot.co.za/2017/05/adjus...But I just use a voltage follower op-amp to drive a fat MOSFET on a big heatsink to act as the "electronic resistor" with a feedback circuit on a current sense. Then you can use a Volt/Amp display to indicate voltage/current that appears on the 'load'. There are lots of designs, Google is your friend. ;-)

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  • Teratron commented on rohmega's instructable Variable Powerbank Supply2 years ago
    Variable Powerbank Supply

    The DAC will not be happy with a negative voltage on it's output, be careful. Yes, you might need a negative voltage rail as well to get to 0V, in which case you could also consider an op-amp to buffer/drive a power transistor in linear mode, rather than swithmode.

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  • Salvaging Rechargeables for Projects

    I have also salvaged a lot of these and built an electronic load to test the charge that the cells could hold to determine which was still good and can maintain a useful capacity. Well done for the recycling!

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  • Teratron commented on rohmega's instructable Variable Powerbank Supply2 years ago
    Variable Powerbank Supply

    Hi. I am sure that your DAC circuit works, hope to use your code myself soon. You can test that by decoupling it and checking that it is supplying the voltages that you expect. The problem with the feedback is that the Vout = 1.25 x (1+R2/R1) normally but + Vdac in your case. Have a look at the basic circuit from the datasheet below. R2 is supplying direct feedback on the output to pin 5. R1 to ground is trying to maintain 1.25V but if you add Vdac to that, you take the circuit out of design envelope.What I would try, have not attempted this on this regulator, but have done it on linear versions, is to tie R1 instead of ground to pin 1, decouple pin 1 from ground and add your DAC output, buffered/amplified 'under' the XL6009 to lift it above ground. That will keep the feedback loop an...

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    Hi. I am sure that your DAC circuit works, hope to use your code myself soon. You can test that by decoupling it and checking that it is supplying the voltages that you expect. The problem with the feedback is that the Vout = 1.25 x (1+R2/R1) normally but + Vdac in your case. Have a look at the basic circuit from the datasheet below. R2 is supplying direct feedback on the output to pin 5. R1 to ground is trying to maintain 1.25V but if you add Vdac to that, you take the circuit out of design envelope.What I would try, have not attempted this on this regulator, but have done it on linear versions, is to tie R1 instead of ground to pin 1, decouple pin 1 from ground and add your DAC output, buffered/amplified 'under' the XL6009 to lift it above ground. That will keep the feedback loop and stability intact. Have a look at Guido Socher's design and how he multiplies the voltage and add current capabiltiy after the DAC circuit in his power supply design: http://main.linuxfocus.org/English/June2005/articl...

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  • Teratron commented on rohmega's instructable Variable Powerbank Supply2 years ago
    Variable Powerbank Supply

    Hi, interesting concept to control the XL6009 with a DAC and nice enclosure but you will need to invest a bit more in your feedback circuit. Because you are adding a DC voltage from the DAC, the feedback from the output which the converter is trying to control, is being interfered with. Keep in mind that it is trying to keep the 1.2V on the FB pin by changing the PWM on the output. That is why you see the "ringing" on the output, basically the control circuit goes unstable.Also when you make big changes on the FB pin with the DAC, you cause massive over reaction on the converter which causes big surge currents on your source which probably goes over the 2.1A that your powerbank can deliver and it goes into self protection.

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  • Teratron commented on vnod2805's instructable The Diode3 years ago
    The Diode

    Nevermind...I just read it wrong...

    Just correct your forward / reverse biased explanation in first paragraph. Forward biased diode acts like an open gate...

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