How to choose an LED driver? Constant Current vs. Constant Voltage


Welcome to SuperLED Lighting Blog and choose an LED driver for your lighting application. This article contains three aspects: 1 LED drive type and its application scope; 2. Relevant parameters to be considered when selecting an LED driver. 3. How to find the LED driver you need on the official website of Mingzhi.
   different from other switching power supplies, LED drive or LED power supply requires high reliability and safety in lighting applications. Its output characteristic curve can fit well with the luminous curve of LED bulb, and has good adaptability. The LED driver converts the AC input power (usually 110VAC and 230VAC) into stable DC power to supply power to the LED bulb and prolong the service life of the LED bulb.

1、 LED drive type and its application range
   all led drives can be divided into two basic types, constant voltage LED drive and constant current LED drive. Of course, some manufacturers have also introduced a combination of two modes of LED driving power supply. They will be introduced one by one later.
1.1 what is constant current drive?
   constant current drive means that the output current value of LED power supply remains constant and the output voltage value changes. Constant current drive has a wide range of applications and is widely used in home and commercial lighting markets.
1.2 what is constant voltage drive?
   corresponding to constant current drive, the output voltage of constant voltage drive is constant. In this way, it can be used in circuits with multiple strings of LED beads in parallel, such as LED strips. Note that the upper limit current resistance is usually connected in series on the LED bar. The output voltage of constant voltage drive is required to meet the voltage demand of the whole LED light bar. Constant voltage drive is usually used in building lighting and landscape lighting applications.
1.3 what is constant current and constant voltage adaptive drive?
  some led drives have the characteristics of both constant voltage drive and constant current drive. When the rated current is not exceeded, it generally works in constant voltage mode, and when the rated current is exceeded, it works in constant current mode. This led driver is flexible in application and can be adapted to a variety of application scenarios.

2、 Relevant parameters to be considered when selecting an LED driver
2.1 input voltage
  the input voltage is indicated on the label of each LED driver. Before using LED driver, it is necessary to know the local rated grid voltage. For example, the voltage in the United States is 120VAC and 277VAC, the voltage in Japan is 110VAC, while the voltage in Europe and China is about 230VAC. Figure 2 shows the grid voltages in various regions of the world.

2.2 power factor
   for more information about this parameter, refer to: power factor correction (PFC) basics
2.3 output current
  when using constant current LED drive, pay attention to the driving current required by the LED bulb you select. The parameter Manual of LED usually gives the rated current value, and the unit should also be noted that 1A = 1000mA.
2.4 output power
   it is necessary to select an LED driver matching the power of LED lamps. The output power of LED driver should be slightly greater than the rated value of LED lamps. If the output power of the driver is just equal to the power required by the LED lamp, the LED driver will always work under full load, which will greatly reduce the service life of the LED driver. Moreover, the rated power of LED lamps is also an average value, and the maximum and minimum power required by multiple strings of LED beads are error. Therefore, the output power of LED drive should preferably cover the power requirements of all lamps.
2.5 output voltage
   the voltage is DC output, in volts (V). For constant voltage power supply, note that its output voltage value needs to reach the rated voltage of your lamp. The voltage levels required for common LED lamps are 12V, 24V and 36V.
2.6 service life
   the service life of LED drive is usually measured in thousands of hours. Also known as MTBF (mean time before failure), it is the time to run the drive until it fails. Generally, using LED drive under rated parameters can ensure its service life and reduce maintenance cost.
2.7 IP level
  what is the waterproof and dustproof grade of your LED driver? If the driver works in the environment of water mist and dust, it is recommended to select LED driver above IP65. If the requirements are more stringent, products above IP67 or IP68 are required, and outdoor LED drivers often need products of this grade.
   the numerical meaning of IP grade is shown in the table below. The first number represents the dust-proof grade and the second number represents the waterproof grade.