I'm building a lighting system for a bike, powered by a dynamo (typically rated 6V, 3W max). The load will include LEDs and a bit of logic (such as N555/ATTiny85 for blinking, etc.). I also plan to include some form of short-term energy storage (for red lights): either a supercapacitor or a small lithium battery.
What is an appropriate choice for rectifying the 6V AC input? Obvious choices are:
- a full-wave diode bridge rectifier (pro: easy and cheap, exists as a single-package; con: but at a low voltage, that 1.5V loss stings a bit);
- a Schottky diode bridge (a bit more efficient, a bit pricier, I don't believe it exists as a single package);
- a simple MOSFET bridge, which I used in a previous iteration of this circuit, but it apparently cannot charge a capacitor (although I believe I used it successfully for that purpose in said previous circuit...), which can have a low drop but is more cumbersome;
- a MOSFET bridge driven by a LT4320: I've never used this component, and it apparently needs at least 9V to work. Also, I've never soldered SMD yet.
- there seems to be a dedicated chip, FDMQ8203, but that is a bit expensive (incl. shipping cost) for a chip I'm not sure to be able to solder (tiny MLP package).
Did I miss any other rectifier circuits, and is my evaluation of the pros and cons of each type of rectifier accurate?