In this project, we have designed a simple 230V LED Driver circuit, which can drive LED directly from the mains supply.
A light-emitting diode (LED) is a type of diode used in optoelectronic devices. It conducts when forward biassed, just like a PN junction diode. This device’s ability to emit energy in the visible band of the electromagnetic spectrum, i.e. visible light, is a unique property.
One of the most important considerations when driving an LED is to maintain a nearly constant current input. An LED is frequently powered by batteries or control devices such as microcontrollers. However, these have their own drawbacks, such as a short battery life.
Driving the LED with an AC to DC power supply is a viable option. Though the AC to DC power supply using a transformer is highly popular and frequently used, it is quite expensive for applications such as driving loads such as LEDs, and it is also not viable to produce a low current signal using a transformer.
We created a simple circuit to drive an LED from 230V AC, taking into account all of the parameters. A capacitor-based power supply is used to do this. This is a low-cost, high-efficiency circuit that can be employed in residential settings.
- 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 is based on the transformerless power supply approach. The X-rated AC capacitor is the key component, and it can lower the supply current to a safe level. These capacitors are designed for high voltage AC circuits and are linked line to line.
The X-Rated Capacitor merely decreases current; the AC voltage can be rectified and adjusted in the circuit’s later stages. A bridge rectifier is used to convert high voltage and low current AC to high voltage DC. A Zener diode is used to rectify the high voltage DC to a low voltage DC.
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 begin, a 2.2F / 400V X-Rated Capacitor is connected to the mains supply. It’s critical to choose a capacitor with a higher voltage rating than the supply voltage. The supply voltage in our situation is 230V AC. As a result, we employed a 400V capacitor.
When the power is switched off, a 390K resistor is connected in parallel with the capacitor to discharge it. Between the supply and the bridge rectifier is a 10 resistor that acts as a fuse.
The full wave Bridge Rectifier is the next component in the circuit. We used a W10M single-chip rectifier. It can withstand currents of up to 1.5 Amperes. The Bridge Rectifier’s output is filtered with a 4.7F / 400V capacitor.
For regulating the DC output of the Bridge Rectifier, we are using a Zener Diode. A 4.7V Zener Diode (1N4732A) is used for this purpose. Before the Zener Diode, we have connected a series resistor of 22KΩ (5W) for limiting the current.
The regulated DC is given to the LED after filtering it out using 47µF / 25V Capacitor.
How the 230V LED Driver Circuit Works?
This project includes a simple 230V LED Driver Circuit that does not require a transformer. The X-Rated Capacitor, the Zener Diode, and the resistor that limits the current in the Zener Diode are the key components of this project. Let’s take a look at how this project works.
The 2.2F X-Rated Capacitor (225J – 400V) will first reduce the AC current from the mains supply. You must utilise the Capacitive Reactance of the X – Rated Capacitor to compute this current.
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.
