Powering LEDs from single Li-Ion cell

[rexxar]

I'm suffering project blindness and can't settle on a design decision. I'm powering a custom RGB LED controller from a single Lithium cell. I decided to add a 5V SMPS for the microcontroller and other peripherals, and I went ahead and used that supply to feed the LEDs, since it had enough current capability. It works well enough, and it's a lot brighter than how I was doing it before (the mosfets weren't going into saturation), but I underestimated how much power the SMPS controller dissipates, and it can sometimes go into thermal shutdown.

My question is should I rearrange the board to get better heatsinking, or should I just go back to using the battery voltage to drive the LEDs? The problem with that is brightness will go down over the battery's voltage range, but the current limiting resistors should dissipate less heat (max I is 700mA).

What do you guys think I should do?

[PeterFW]

What do you guys think I should do?

You are using a step up regulator from a Li* cell to step up the voltage to 5V and then drive the LEDs through current limiting resistors from the 5V rail?

You are wasting a lot of power, my advice would be to use a proper constant current boost LED driver on a battery powered application.

You should check that you do not exceed your discharge rate of the Li* cell too.

[Fungus]

What do you guys think I should do?

Get a better power supply.

(nb. You haven't told us anything at all about the existing supply or the power requirements)