In this project, we have devised a straightforward 230V LED Driver circuit capable of directly powering LEDs from the mains supply.
A light-emitting diode (LED) is a specific type of diode utilized in optoelectronic devices. It conducts when forward-biased, similar to a PN junction diode. Its distinguishing feature is the ability to emit energy within the visible range of the electromagnetic spectrum, specifically visible light.
When driving an LED, one crucial consideration is maintaining a nearly constant current input. LEDs are often powered by batteries or control devices like microcontrollers, but these solutions come with their own limitations, such as short battery life.
Using an AC to DC power supply to drive the LED proves to be a feasible alternative. Although AC to DC power supplies with transformers are widely employed and popular, they tend to be cost-prohibitive for applications like powering loads such as LEDs. Furthermore, they are not well-suited for generating a low-current signal using a transformer.
We have developed a straightforward circuit that addresses all the relevant parameters for driving an LED from 230V AC power. This circuit employs a capacitor-based power supply, offering a cost-effective, high-efficiency solution suitable for residential applications.
Outline
- 230v LED Driver Circuit Principle
- 230v LED Driver Circuit Diagram
- Components Required
- How to Design a 230V LED Driver Circuit?
- How the 230V LED Driver Circuit Works?
- Advantages
- Applications of 230V LED Driver Circuit
- Limitations of 230V LED Driver Circuit
230v LED Driver Circuit Principle
The 230V LED Driver circuit employs a transformerless power supply methodology. At its core, the circuit relies on the use of an X-rated AC capacitor, which effectively reduces the supply current to a safe level. These capacitors are specifically designed for high voltage AC circuits and are connected in series.
The X-Rated Capacitor’s primary function is to regulate current; the subsequent stages of the circuit are responsible for rectifying and adjusting the AC voltage. A bridge rectifier is utilized to convert high voltage and low current AC into high voltage DC. To further refine the high voltage DC into low voltage DC, a Zener diode is employed for rectification purposes.
230v LED Driver Circuit Diagram
Components Required
- 2.2µF Polyester Film Capacitor (225J – 400V)
- 390KΩ Resistor (1/4 Watt)
- 10Ω Resistor (1/4 Watt)
- Bridge Rectifier (W10M)
- 22KΩ Resistor (5 Watt)
- 4.7µF / 400V Polarized Capacitor
- 10KΩ Resistor (1/4 Watt)
- 4.7V Zener Diode (1N4732A) (1/4 Watt)
- 47µF / 25V Polarized Capacitor
- 5mm LED (Red – Diffused)
How to Design a 230V LED Driver Circuit?
To initiate, we connect a 2.2μF / 400V X-Rated Capacitor to the mains supply. It’s essential to select a capacitor with a higher voltage rating than the supply voltage. In our case, the supply voltage is 230V AC; hence, we have opted for a 400V capacitor.
When the power is switched off, we employ a 390K resistor connected in parallel with the capacitor to discharge it. Additionally, there is a 10Ω resistor placed between the supply and the bridge rectifier, serving as a fuse.
The following component in the circuit is the full-wave Bridge Rectifier. We utilize a W10M single-chip rectifier, which can withstand currents of up to 1.5 Amperes. The Bridge Rectifier’s output is smoothed using a 4.7μF / 400V capacitor.
To regulate the DC output from the Bridge Rectifier, we introduce a Zener Diode. Specifically, we employ a 4.7V Zener Diode (1N4732A). Preceding the Zener Diode, there is a series resistor of 22KΩ (5W) to restrict the current.
The regulated DC output is directed to the LED after further filtering with a 47µF / 25V Capacitor.
How the 230V LED Driver Circuit Works?
This project presents a straightforward 230V LED Driver Circuit that operates without the need for a transformer. Its essential components include the X-Rated Capacitor, the Zener Diode, and the current-limiting resistor associated with the Zener Diode. Let’s delve into the functioning of this project.
Initially, the 2.2μF X-Rated Capacitor (225J – 400V) serves to diminish the AC current sourced from the mains supply. To achieve this, you must calculate the Capacitive Reactance of the X-Rated Capacitor.
Below is the formula for calculating capacitive reactance.
So, for 2.2µF Capacitor, XC can be calculated as follows.
So, from Ohm’s Law, the current that the capacitor allows is given by I = V/R.
Hence, the current through the capacitor is = 230/1447.59 = 0.158 Amperes = 158mA.
This is the total current that enters the bridge rectifier. Now, output of the Bridge Rectifier is filtered using a Capacitor. It is important to select an appropriated voltage rating for this capacitor.
The input to the Bridge Rectifier is 230V AC, which is the RMS Voltage. But the maximum voltage at the input of the Bridge Rectifier is given by
VMAX = VRMS x √2 = 230 x 1.414 = 325.26 V.
As a result, a filter capacitor rated at 400V is required. The DC voltage after being rectified is roughly 305V. This must be reduced to a workable range in order to light the LED. As a result, the Zener Diode is employed in this project.
This is accomplished by using a 4.7V Zener Diode. A Series Resistor, the Power Rating of that Resistor, and the Power Rating of the Zener Diode are all crucial aspects to consider when using a Zener Diode as a regulator.
The Series Resistor comes first. The current going through the Zener Diode will be limited by this resistor. The series resistor can be chosen using the formula below.
Here, VIN is the input voltage to the Zener Diode and is = 305V.
VZ is the Zener Voltage (which is same as the load voltage VL) = 4.7V.
IL is the load current i.e. the current through the LED and is = 5mA.
IZ is the current through the Zener Diode and is = 10mA.
Therefore, the value of the Series Resistor RS can be calculated as follows.
Now, the Power Rating of this Resistor. The Power Rating of the series resistor is very important as it determines the amount of power the resistor can dissipate. To calculate the power rating of the Series Resistor RS, you can use the following formula.
Finally, the Power Rating of the Zener Diode. You can use the following formula to calculate the Power Rating of the Zener Diode.
Based on the above calculations, we have chosen the series resistor of 22KΩ Resistance rated at 5W and a 4.7V Zener Diode rated at 1W (actually, a quarter Watt Zener would suffice).
The rectified and regulated voltage with limited current is given to the LED.
Advantages
- With the help of this 230V LED Driver Circuit, we can drive LEDs directly from the main supply.
- This project is based on a Transformer Less Power Supply. Hence, the final build won’t be a large one.
Applications of 230V LED Driver Circuit
- This circuit can be used for home lightening systems.
- It can be used as an indicator circuit.
- One can fix this circuit with the door bell to give indication.
Limitations of 230V LED Driver Circuit
- Since 230V AC supply is being directly used here, this circuit can be dangerous.
- This circuit is best suited for domestic applications using single phase supply. This is because, in case of three phase supply, if any of the phases accidently touches the input terminal, it can prove to be quite dangerous.
- The capacitor can produce spikes at mains fluctuations.
