LED boards for lamps, floodlight, spotlights, LED panel.
Most modern lighting devices, from a pocket flashlight to a stadium floodlight, use an LED module (LED matrix) as a light source. This is usually an aluminum (less often copper) board, on which one to several hundred LEDs can be located. Unlike LED strips, such a board dissipates heat better. This allows LEDs to be placed more densely and produces more powerful and more compact light sources. Such LED assemblies can be divided into 2 types: SMD modules and COB modules.
Aluminum boards with SMD LEDs are most often used in lamps and floodlights with a wide light scattering angle. The LEDs are usually placed evenly over the entire area of such a board and provide uniform diffused light. Such LEDs can be additionally equipped with diffusing lenses to increase the LED light scattering angle.
COB boards are most often used in lamps and spotlights with a small beam angle. On such boards, the LEDs are located very close to each other. The result is a bright point source of light. The beam angle of such light can be easily changed with a single lens (usually focusing). Such standards are used in spotlights, track lights, car headlights, flashlights, etc.
As a power source, such boards usually use an LED driver. This can be either a separate device or part of an LED assembly circuit. Repairing LED boards with a built-in LED driver requires certain skills and knowledge of electrical engineering. As a rule, LED modules of this type are used in inexpensive lamps and spotlights. Often, their repair can cost more than a new device. In extreme cases, you can replace the entire LED module with a similar one.
If the LED board is powered by a separate LED driver, then the ability to replace only a part of such a device (LED module or driver) significantly simplifies and reduces the cost of its repair. In this case, each of these parts, as a rule, has its own marking indicating its technical characteristics. How to choose a new driver to replace the old one based on its characteristics can be read in the section "LED driver". In most cases, it is the first to fail. If the LED driver shell does not indicate its characteristics or only part of them are indicated, you can find out the parameters of a suitable model based on the characteristics of the LED board.
What current and voltage is needed for the LED board in the lamp?
Typically, SMD2835 type LEDs are used in lamps. The consumption current of one such LED is 100-150 mA. Most often, SMD LEDs with an operating voltage of 6 volts are used now, less often - 3 volts. To determine the operating voltage of an LED in a lamp, it is enough to apply a low-power voltage of 3 volts to the contacts of one of them. If the LED lights up, then each LED in this circuit has an operating voltage of 3 volts. If not - 6 volts (or the polarity of the contacts was mixed up when connecting). COB modules usually use LED crystals with a consumption current of 100-150 mA and an operating voltage of 3 V.
LEDs can be connected to each other on the board in parallel, series, and parallel-series. When LEDs are connected in parallel, their consumed current is summed up. When connected in series, their working voltage is summed up. Usually, there is a marking on the board indicating how the LEDs are connected. Their parallel connection is designated by the letters P or B. Series connection is designated by the letters S or C.
For example, if the board says: 2P6S (or 2B6C) – this means that the LEDs have 2 parallel connections and 6 serial ones. These can be 2 parallel lines, each with 6 LEDs connected in series. Or these can be 6 pairs of LEDs connected in series, with the diodes in each pair connected in parallel. In both cases, the current consumption of one LED is multiplied by 2, and the operating voltage of one LED is multiplied by 6.
Knowing the total current consumption and voltage of the LED board, you can select a suitable power source. How to do this is described in the section "LED Driver".
