A linear regulator will drop any extra voltage across the device and 'burn' it as heat. The total power wasted will be the voltage dropped multiplied by the load current.I dont understand what happens to the missing power. Doesnt this mean it will be disapating some as heat?
That's not the desire. It seems to keep coming back to using a simple zener shunt, but that creates too much heat when the phone is not connected.
It can be switch mode but you seem to have discounted these already because they are too complex?Can someone recommend the LDO example I should be using (preferably under $1 in quantity). Shouldnt it be a switch mode version if I want high efficiency?
You can, such items are standard components used with solar panels - here's one (nice low cost) solution:Im surprised I cant find a simple solution for this.
How did you test this?Hello again, I have followed many of you, advising to use LDO regulator.
I tried using a low drop out regulator (http://www.farnell.com/datasheets/808935.pdf?_ga=2.108242309.680706486.1494294481-1373478196.1490314122) hooking it up in a standard manner.
Sadly whilst this produces 5v at the output, it does not pull the solar panel down at all, into its MPP, so little to no current is generated. (20ma)
I only need to regulate the voltage when no current is being drawn, once the phone starts pulling power, I suppose I want to bypass the LDO regulator.
Im surprised I cant find a simple solution for this.
Getting pretty frustrated now.
Thanks Nigel - this buck converter looks nice but I need to build this for production into a USB plug, and only need 300ma not 2A, thanks again.You can, such items are standard components used with solar panels - here's one (nice low cost) solution:
camerart thanks I had just been thinking the same - that it needs something on the input side doing PWM with the capacitor like it is on the output, so we can set the voltage at the optimum, or better, the max current or MPPHi,
...The SP charges a capacitor to the Battery charge voltage, then the capacitor uses its charge to charge the battery, then is switched back to capacitor charge and so on....[snip]
Hi S,camerart thanks I had just been thinking the same - that it needs something on the input side doing PWM with the capacitor like it is on the output, so we can set the voltage at the optimum, or better, the max current or MPP
It would need to oscillate the input capacitor's voltage near to the MPP for efficiency, deliver it to the LDO regulator circuit discussed above.
Is there such an IC circuit without getting into the whole MPP tracking discussion?
And if so, can it just be 'bolted on' or is there some impedance matching or some such needed?
Maximum Power Point. Every panel has a "sweet spot" where the product of the panel voltage and the panel output current hits maximum Power output. If you are trying to recharge a battery in the shortest possible time, then you would like the charge controller to operate the panel at Vmppt.What is MPP?...