I am not an Electrical Engineer, but know some basics from reading and practicing on this topic. Please evaluate my circuit for a Super Capacitor Power Bank to charge my phone, and clarify my points below.

[![Super Capacitor Power Bank](https://i.stack.imgur.com/cNBKi.png)](https://i.stack.imgur.com/cNBKi.png)

1. If the input is fixed at 2.5V, do I need any protection board for a 2.7V Super Capacitor (3000F)
2. I plan to power the circuit using USB, so I need to step down 5V to 2.5V. One option is to buy a step down module, but is there any other simple technique I can use? Diodes?

Basically, the USB input charges up the capacitor and the LED lights up. The top left switch is not required, but it simulates the Power Bank being charged or not. When the switch on the top right is on, the capacitor discharges into a Step-Up Booster USB Charge Module, like this...

<http://www.ebay.com/itm/5PCS-PFM-Control-DC-DC-USB-0-9V-5V-to-5V-dc-Boost-Step-up-Power-Supply-Module-/201542969731>

Perhaps, it may be better to use two capacitors in series. Would I need a protection board, if I keep the input voltage at 2.5V max?

Anything else I am missing?