Now that my dynamo USB project is reasonably mature I've moving onto something easier. The idea is to create something like this:
https://www.sjscycles.co.uk/lighting/0-busch-muller-toplight-line-small-rear-dynamo-light/
This device includes a supercapacitor but looses brightness at a standstill, decaying over 4 minutes. Probably it's just using resistors. I'd like to make an improvement by utilising a larger supercapacitor and a buck/boost circuit for efficiency.
Such chips seem to exist, although I haven't found the chip ID yet: https://www.aliexpress.com/item/5pc...ost-Buck-Low-Noise-Regulated/32365767349.html
The topology will be;
5.25v reg -> 5.5v supercapacitor ->buck/boost -> 3x red piranha led, 2.1v (variable) 0.07A current (constant until impossible)
That chip works down to 0.7v but gives out 3.3v, but perhaps it or a similar model can offer the low voltage support and a constant current mode.
The efficiency probably wouldn't be much higher, it's only 70mA after all, but it would allow usage of the 0.7v-2.1v range of the supercapacitor.
Any thoughts?
https://www.sjscycles.co.uk/lighting/0-busch-muller-toplight-line-small-rear-dynamo-light/
This device includes a supercapacitor but looses brightness at a standstill, decaying over 4 minutes. Probably it's just using resistors. I'd like to make an improvement by utilising a larger supercapacitor and a buck/boost circuit for efficiency.
Such chips seem to exist, although I haven't found the chip ID yet: https://www.aliexpress.com/item/5pc...ost-Buck-Low-Noise-Regulated/32365767349.html
The topology will be;
5.25v reg -> 5.5v supercapacitor ->buck/boost -> 3x red piranha led, 2.1v (variable) 0.07A current (constant until impossible)
That chip works down to 0.7v but gives out 3.3v, but perhaps it or a similar model can offer the low voltage support and a constant current mode.
The efficiency probably wouldn't be much higher, it's only 70mA after all, but it would allow usage of the 0.7v-2.1v range of the supercapacitor.
Any thoughts?