LED Circuit Design
LED, acronym for light emitting diode, has revolutionized the fields of incandescent lamps. LED uses miniscule power to operate, thereby saving on electricity. It is also much cooler than an ordinary bulb and does not produce any heat, thereby reducing the risk of fire and, last but not the least, it does not involve glass in manufacture, but epoxy lenses, that are more resistant to breakage.
What is LED?
Basically, LED is a semiconductor device designed to emit visible light when electric current is passed through it. The light that it emits is monochromatic, that is of single wavelength, and is not very bright. However, its lower power requirement coupled with improved efficiency and more lifetime and multiple uses offsets this disadvantage.
Today, LED is being extensively used in indicator lights, Liquid Crystal Display panel backlighting, fiber optics and opto-isolator that acts as a separator for various stages in an electronic system connected together, thereby preventing interaction.
Basic LED circuit
As the name implies, a Light emitting diode circuit help to run an LED. It needs to be designed in such a way as to provide the necessary illumination without damaging the Light Emitting Diode. High power LEDs require a more complicated current source circuits for illumination.
The basic LED circuit comprises of the following:
1. Voltage source
2. Ballast resistor
3. Light emitting Diode.
A switch can be used to open and close the circuit. This basic circuit isn’t very efficient compared to the advanced circuits, since it loses energy due to the resistor. However, more complex circuits improve energy efficiency.
This is not to say that a basic circuit has limited utility. On the contrary, this circuit has a slew of applications that includes appliances like phone chargers.
Power-source requirements
LED faces a dilemma.
1. LED remains unlit due to the absence of any current flow in case the voltage is lesser than the threshold level.
2. LED may get destroyed due to overheating in case the voltage level is very high and the current happens to be more than the optimum rating,.
The success of LED depends upon the power source. LED needs appropriate current for it to function satisfactorily. To ensure this, various components are used, such as series resistor that passively stabilizes the Light Emitting Diode current. Constant current regulator helps to stabilize the output over an extensive range of input voltages.
Pulsed LED operations
Pulsed LED is achieved by applying power periodically or intermittently. If the flicker rate is more than the human flicker fusion threshold level, the Light Emitting Diode appears continuously lit. To power on/off pulses, pulse-width modulation is used through several types of microprocessor boards.
Doxals foray into LEDs
Doxals Engineering, a Singapore-based electronic engineering solutions company, designs LED circuits of varying complexities to meet all kinds of LED demands. It uses state of the art technology to design circuits that withstand the test of time.