4AA Battery Powered 12V LED Spotlight - 12V Power Supply

Most of the electronic projects and electronic devices are required 12V power source; typically a 12V sealed lead acid battery or AC powered power supply. These are typically large, heavy, difficult to handle, and expensive; portability is less. The best solution is to use a DC-DC Step up converter. These types of convertors are inexpensive, light weight and easy to use. Also provides power management and easy to work with renewable energy sources.

The input power source could be rechargeable AA batteries. Let’s make an environment friendly 12V/130mA power supply!

Step 1: Design the Prototype

The heart of this application is LT1073 IC. It is a power management IC which steps up low voltage into high voltage by switching.

First I etched four PCBs for the prototype using a PCB design software and some other tools. The PCBs are very small (4cmX2cm) because components need to be solder as close as to the IC; because of the performance issues. I made ground copper track as wide as possible.

Now my prototype works fine and I decided to make the PCB in large quantity. I did some changes and sent my PCB file to a local PCB production company and first I got 100 pieces of PCBs. The PCBs are in good quality with solder spots and copper shield; easy to solder.

Step 2: Component List

100uf Electrolytic Capacitor 16V C1,C2 -2
100Ohms Resistor 1/4W R1,R2 -2
1N5817 Schotkey Diode 1A D1- 1
150UH Radial Power Inductor 1A IND1- 1
LT1073CN8-12 IC DIP Package IC1 -1
IC Base 8 PIN -1
PCB to Wire Connector- 2
4AA Battery Holder- 1

Step 3: TESTING WITH LED SPOTLIGHT

The input is around 5V and the output is 12V @ 130mA. I used 12V LED spotlight from Futurlec. http://www.futurlec.com. There are many types of LED Spotlights (MR16) with different number of LEDs. Before buy a one makes sure that the current rating is less than 130mA. Our power supply can deliver maximum 130mA. These are the ratings of MR16 LED spotlight:

Ratings:
Operating Hours: 20,000 hours
Operating Voltage: 12V
Intensity: 55,000 mcd
Forward Current: 80 mA @ 12Vdc
Viewing Angle: 30 Degrees

Absolute Maximum Ratings:
Operating Voltage(V): 14 V
Operating Temperature (Topr): -25oC to +85oC
Storage Temperature (Ts): -35oC to +100oC

You can use this spotlight as an emergency light source.