1.8W LED bulb

Preface:
The light bulb was originally intended to be used in the corridor and was powered by solar energy + lithium battery. In this application scenario, the ordinary 2835 RA80 bulb can be used. Since we don’t have it at hand at the moment, this design uses the RA97 RG0 low blue light bulb. The overall electrical safety of this project should not be a big problem, but it is not recommended to reproduce it because lamp beads are difficult to buy. If you need to reproduce it, you will have to change the current limiting resistor or replace the lamp bead combination.
Personally, I feel that the brightness is quite good, there is no flicker, and the light is relatively soft, making it comfortable to look at. For specific effects, see the video
light panel display below
, which is particularly small. . The schematic diagram of 32mm diameter and 1.2mm thick
selection
is as shown above. Since
the driver chip is powered by a lithium battery, the driver chip here uses a screen backlight driver chip.
The input voltage is 2.7V-5.5V, which perfectly matches the voltage of lithium battery. There is nothing much to say about
LED lamp beads
. The 2835 LED lamp beads are RA97 RG0 with low blue light. This is not easy to buy. It starts at 1k. It is recommended to replace
the inductor.
Since the size of the lamp board is very small, and the lamp itself does not require a particularly large current, I chose a 1210 power supply inductor. The peak current is 450ma. Pay attention to
the current limiting resistor.
Is the Vfb of ET5120A or 5120 different?
5120A: Vfb=200mv 5120: Vfb=300mv
Iout = Vfb/R where R is R1 in the schematic diagram