How to choose power supply that matches the light strip?

What is an LED driver?

The LED driver is used to convert the city power supply (for example, in mainland my country, it is 220V AC with a power frequency of 50 Hz) into the voltage and current range required for the LED light source to work stably (generally DC voltage, and the current is preferably constant).

So, the key to choosing a driver lies in your LED light source.

When the LED is working, the current needs to be stable. According to the diode volt-ampere characteristics of the LED, you will find that when the forward voltage is added to the dead zone voltage, a slight voltage fluctuation will cause the current flow through the light-emitting diode LED to fluctuate exponentially.

Select a driver with stable voltage and current regulation to ensure optimal LED performance. Delve into the specifications to match the driver's output with the LED's requirements. The ultimate goal is to avoid fluctuations that can reduce lifespan and efficiency.

This is related to the classification of ready-made drivers: constant voltage drivers, constant current drivers, and constant current current voltage drivers. We will not discuss the RC step-down solution with poor quality and stability here.

Focusing on input and output voltage and current is key to ensuring compatibility. Once these parameters align, other factors like power factor and efficiency become secondary for most applications. If you need to delve deeper into specifics, those additional parameters can help optimize performance.

Matching the input voltage of the driver with your power supply is crucial. The input current is generally less critical for compatibility but still worth checking to ensure it aligns with your system’s capabilities. Our mainland China is AC 220V input. If it is a foreign partner, it may be AC110V in Japan and the United States, or AC277V in some parts of the United States. Some countries, such as Malaysia, will be AC240V. In most European countries, that is AC220V voltage.

Constant voltage driver is a driver with constant output voltage, commonly outputting 5V, 12V, 24V, 48V, etc. It is usually DC direct current; suitable LED light sources are generally low-voltage light strips. Some light sources, such as outdoor pool lights, also need to use low-voltage 12V input, mainly to avoid leakage and harm to people.

In an LED circuit, if the voltage is constant, the current is determined by the resistance of the circuit or the design of the current control mechanism. For LEDs, which typically require constant current for optimal performance, the driver is designed to regulate the current even if the voltage is constant.

Here's how it works:

1. Constant Current Drivers: These drivers are specifically designed to supply a consistent current to the LED regardless of voltage fluctuations. They adjust the output voltage as needed to maintain the set current.

2. Resistors: In simpler LED circuits, current is controlled by resistors. Ohm’s Law (V = IR) dictates that for a given constant voltage, the current flowing through the circuit is determined by the resistance value. For LEDs, resistors limit the current to a safe level.

3. Electronic Control: More advanced drivers use electronic feedback mechanisms to monitor and regulate the current, ensuring it stays at the desired level even if the LED's forward voltage changes due to temperature or aging.

In summary, with a constant voltage, current is managed either by using a constant current driver or by adjusting the resistance in the circuit.

Matching LED light strip steps

1. Determine the voltage of low-voltage light strips

Low-voltage light strips are easy to identify. Generally, they are marked with DC12V or DC24V on the flexible board of the light strip. As shown below:

Therefore, you only need to find the right output voltage, but that is only the first step. The second step will be to choose the right power.

2. Power selection.

Your light source load mainly determines it.

For example: your light strip is 12VDC, one meter is 12 watts, and there are 4 meters of light strips in total, so the total wattage of the light strip is 12x4=48W. Then you need to choose a constant voltage driver of 48W or more. There are regular wattages on the market, such as: 35W, 50W, 60W, 75W, 100W, 150W, 200W, 350W, etc. Then, there is no problem choosing more than 60W.

Why can't we choose 50W?

Mainly because we need to leave some margin for the constant voltage driver. Although the constant voltage drivers of big brands can output at full load, it is better to leave more margin than nothing. Not to mention those with false maximum power. How much is generally reserved? The industry generally believes that about 20% is enough. Therefore, 48W plus 20% is about 58W, and there is no problem choosing 60W.

So, can I choose a bigger one?

For example, if I have a 150W 12VDC constant voltage driver, can I use it? Of course, no problem. It is the same as a car that can carry 5 people, but now only has two people. If it is a new purchase, then it is enough to use it, and there is no need to spend unnecessary money.

I hope this article is helpful to you.

Ottima is a 18 years manufacturer of LED driver. Our primary focus is Constant Voltage Dimmable IP20/IP67—our Certificates: UL ETL CE RoHS SAA RCM etc. Welcome to visit our website “ottima-tech.com” to choose drivers. 

North America is our main market, we are selling many drivers to USA and Canada, and have worked with many led power supply distributors and lighting manufacturers for years, some are members of IALDLIRC. OEM/ODM is welcome, ODM is also available if your need is large.

We will continue to produce more competitive, environmentally friendly and energy-saving products to meet customers' needs and create win-win business with you!