I like the 12V LED. But I have only 3V of batteries. So, No light.
With this circuit, I can get light of the LED.
It is a 3V to 12V boost converter circuit. To turn a DCV source of 3.3V-5V into 12V-13.8V at a max current of 100mA.
They are a type of switching power supply that uses KA34063 or MC34063. Which is better than an old circuit. Because of input low voltage, high efficiency with the output adjustable voltage.
If you cannot imagine. I will show why you should use this circuit.
I have LED light Bulb as Figure 1. It is cheap and super bright, best running with 12V.
Do you know how many it uses the current? If you do not know. Let’s learn with me.
Figure 3 Real measuring a current of 12V LED light bulb
You will see that the ammeter shows a current of 0.024A or 24mA. So, this LED uses low power consumption (P), about 0.2 watts.
P = V x I
12V x 0.024A = 0.228 watts only.
Second, if we have a NiMH AA battery, the single battery gives of 1.2V. Although, you connect them in series with three batteries. But a total of 1.2V AA battery are 3.6VDC.
See in Figure 4.
So it cannot be used for the 12V LED light bulb.
Figure 4 as 3 AA battery 1.2V is connected in series
How to add voltage up
We need the DC boost converter circuit to convert input 3.6V or 3.7V to 12V output.
As Figure 5 the circuit diagram of DC boost converter
This circuit can help him because:
- Used for a power supply, 3.3-5 volts 750 mA up
- Can apply voltage 12-13.8 volts depends on the power supply input
- If using the power supply of 5 volts DC current 300mA can apply the output; voltage is 12 volts DC at 100 mA maximum
- If using the power supply of 3.3 volts DC current 660mA can apply the output; voltage to 12 volts DC at current maximum to 50 mA
- Maximum current output: 100 mA
- Normal Switching frequency about 43 KHz
- Can adjust the output voltage
- There is power on LED display
How it works
The circuit will show in Figure 5, the operation starts with when we apply the power supply to the circuit. The IC1 will act as the step-up voltage converter. The voltage will increase to pin 1 of IC1-KA34063 through diode D1 to OUT point. We can adjust the output voltage by adjusting at VR1.
How to assemble the circuit
He bought the project as PCB board so easy to use but you can buy all parts as the list below. Then, you may assemble circuits on the perforated board or DIY Glass Fiber Prototyping PCB Universal Board.
Testing and how to use
As Video below We try to experiment with LED use the 3.6V battery again. The LED will without the light.
Then, He connects the wires or the power cable to LED easy to use.
And Then He tests the circuit
On the PCB; He connects the power line 4, the terminal of the circuit.
As Figure 6: Testing This DC-step-up-converter citcuit using KA34063
- Apply the 3.6V battery—or 3.7V mobile batts to the input terminal.
- Apply the LED to the output terminal and measure the LED voltage.
- Adjust the VR-10K until we read voltage is 12V
- Measure current of LED is 24mA at voltage 12V
- Measure current of the circuit is 100mA at 3.9V
Thus we have power input is 0.1A x 3.9V = 0.39W
But we can use load (LED) at power 0.025A x 12V = 0.3W
We will see that use low voltage input make we have high voltage output at low power using.
- Input terminal connects DC power supply voltage of 3.3V, 3.7V, 4.5V, up tup 5V.
- The output terminal, we use this as DC power supply to any loads. Which this voltage can change by an input voltage level, and adjusting VR1.
Parts you will needs
D1—1N5819, 1A, 40V Schottky rectifier Diode
IC1—KA34063 or MC34063, 1.5-A Peak Boost/Buck/Inverting Switching Regulators
I get many questions from my friends. These may be useful for you, too.
Note: I bought this kit and not design this circuit myself. I am just using it before you. But I am happy that it works well. And, I want to see you happy like me.
You may buy components or Kits here.
Do we use 1N4007 instead of 1N4007?
No, You can’t. Because they are different.
1N4007 is a standard rectifier, 1A 1000V. It works slow.
A 1N5819 is Schottky rectifier,1A 40V. It works faster. So, it is good at switching than 1N4007.
You read: 1N5819 rectifier replaces with 1N4007 rectifier??
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