Recent content by mbanzi

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  1. M

    repairing a Supernova Triple dynamo headlight

    Fantastic work Steve! Will be an interesting exercise to try and build that circuit...
  2. M

    Driver help for a Cree XP-G2 Triple

    Thanks Steve. BTW, I'm going to start up the MPPT dynamo driver project again soon - expect many questions then!
  3. M

    Driver help for a Cree XP-G2 Triple

    I have a Cree XP-G2 S3 Triple MCPCB left over from a dynamo project that I'm planning to use for a battery powered light. What's the best approach to take with a triple? Do I keep them in parallel and run them at 3V or serial at 9V? Any recommendations for driver boards (3 mode is ideal) &...
  4. M

    Standlight vs Voltage Doubler

    Thanks Steve! Once I drew a timing diagram it all made sense to me - I would have never thought of that. I guess that's why my my EE friends say microprocessors make you lazy.
  5. M

    Standlight vs Voltage Doubler

    Steve, as usual, you are correct! I did not take the full-wave rectifier into account, which I should have after staring at the waveform on the oscilloscope. The math makes more sense if the dynamo output AC frequency is doubled. I probably won't even mess with the values then.
  6. M

    Standlight vs Voltage Doubler

    In case anyone else is curious, I believe this means the values of R1 & C2 in Steve's circuit determine the threshold speed at which all LEDs turn on. In this case T = 78.7K * 0.2uF = 15.74ms (approx also depends on Vdd). A 15.74ms period = 63.5Hz frequency from the full-wave rectifier, or...
  7. M

    Standlight vs Voltage Doubler

    That's another advantage of software - I put my notes in my work :D. Thanks Steve, that make sense. I think I was confusing myself thinking it was in non-retriggerable mode.
  8. M

    Standlight vs Voltage Doubler

    Steve, I'm trying to understand how you use the CD4538 MMV as the "speed switch" in your original SonOne Two Standlight circuit. The rectified & un-smoothed output from the dynamo is sent to the first MMV's leading edge trigger input. Depending on the bike's speed the rectified input's...
  9. M

    Standlight vs Voltage Doubler

    Did some more testing on the buck converter tonight (minisystem's design) and something doesn't make sense to me??? I had the converter hooked up to my bench power supply, pushing 15.6V / 0.43A into the buck converter. I measured voltage & current going out of the converter into the LEDs: 8.96V...
  10. M

    Standlight vs Voltage Doubler

    Thanks to both Steves for the detailed replies. One of my EE friends warned me that I'm opening a Pandora's Box here! I think because there are so many ways to skin the proverbial cat here, things get complicated fast. What I need to do is complete my testing jig that will spin the wheel at a...
  11. M

    Standlight vs Voltage Doubler

    Thanks Steve that will be great! With the next versions I plan to increase the PWM frequency to the 200-250kHz range, whatever provides enough resolution "steps" in the micro. Then I can also get rid of the massive inductor I have on there. One problem with using the modules as I have been...
  12. M

    Standlight vs Voltage Doubler

    Finally made some more progress tonight with the switching buck regulator. I decided to use minisystem's design and then work from there. I used the same low-ish 32kHz PWM frequency he used & the same component values, with the addition of 2 mosfets to switch out one or two of the series LEDs at...
  13. M

    Standlight vs Voltage Doubler

    I'm trying to understand the buck converter using P & N mosfets :confused:: If I'm generating PWM from the ATtiny (regular & complementary waveforms with dead time added), do I still need an inverting output for the high (P-channel) driver? What would good matching P & N mosfets be for the...
  14. M

    Standlight vs Voltage Doubler

    Turned out to be very simple to add dead time - just 2 additional lines of code! You set the dead time for the regular & complementary wave separately, so you could have different values if that was required. This is a 10kHz PWM signal with the complementary output turned on, no dead time...
  15. M

    Standlight vs Voltage Doubler

    No I'm not and you're not the first to ask that. Mbanzi is a nickname I got years ago. Got very annoyed at this M.Banzi person taking my username on many sites until I realized who it was!
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