LED backlight strips are now standard in modern flat-panel displays and TV sets, providing picture-enhancing side/edge lighting in thin displays. For engineers, integrators or procurement specialists, understanding current consumption is crucial for power-supply sizing, thermal management, reliability and cost of ownership. This article examines typical current draw characteristics of LED backlight strips used in TVs, how to calculate and estimate them, what factors influence the current, and practical guidelines for specification and sourcing. We also introduce a supplier of LED backlight strips that offers a broad product range.
While TV manufacturers do not always publish in-depth current-draw data for the backlight subsystem, general LED strip technology provides useful benchmarks to guide estimates. Several public resources for LED strips (outside TV-specific use) provide current draw insights:
For analog RGB LED strips, each “segment” of 3 LEDs on a 12 V supply can draw about 60 mA at full white (i.e., red+green+blue all on).
For generic LED tape rated at 12 V, with wattage given per metre, you can compute current: for example 24 W per metre at 12 V implies 24 W / 12 V = 2.0 A per metre.
Reports of actual measurements show that a strip of 60 LEDs drew about 3.0 A at full brightness.
While tv backlight strips may differ in LED type, layout and drive scheme, these numbers help orient expectation.
Here is a rough table of typical values for a simplified scenario:
| Configuration | Voltage | LED count / metre (approx) | Estimated current at full white* |
|---|---|---|---|
| Simple 12 V strip, 60 LEDs/m | 12 V | ~60 LEDs/m | ~1.2 A/m (based on 60 mA × 20 segments) |
| Higher density 12 V strip, 120 LEDs/m | 12 V | ~120 LEDs/m | Possibly ~2.4 A/m (doubling density) |
| TV-specific backlight strip (edge lighting) | typically ~30-40 V or 12-V depending on design | varies by panel size and LED rows | From hundreds of milliamps to a few amps depending on size |
“Full white” means all LEDs at maximum brightness; normal operational current may be significantly less.
Several key factors determine the actual current draw of a TV’s backlight LED strip:
Voltage rating and power-rail architecture: Some strips are designed for 12 V, 24 V, or even 30-40 V depending on how many LEDs are in series and the panel layout. The higher the voltage with the same power, the lower the current for given wattage.
LED type and efficiency: Modern LEDs have higher luminous efficacy and may draw less current for given brightness than older types. If the backlight uses high-efficiency LEDs, current draw is reduced.
Number of LED modules / rows: A TV panel may have multiple LED rows (edge-lit) or full-array backlight. More rows or more LED count directly increases current.
Brightness setting and dimming control: Not all time will the LEDs be driven at 100 % white. Many use PWM (pulse width modulation) or current control to dim the backlight, so the real current draw averages lower.
Thermal and voltage drop losses: Over long strips and higher current flows, voltage drop along the strip increases, reducing brightness and effective current. Also as temperature rises, LED forward voltage drops, which may alter current draw.
Panel size and backlight layout: Larger TVs (e.g., 60 inch, 70 inch) typically require longer or more LED strips, increasing total current draw compared to smaller panels.
When you have a specific TV backlight strip or are sourcing one for a custom build, you can estimate current draw as follows:
Obtain the rated voltage and wattage (if provided) or identify LED count and density.
Use the basic formula: [ I = \frac{P}{V} ] where P is the total power of the strip and V is the supply voltage.
If only LED count and current per segment is given, multiply segment current by number of segments. For example, if each segment draws 60 mA at 12 V and there are 20 segments per metre, current = 60 mA × 20 = 1.2 A per metre.
Add margin for safety: Always specify a power supply with higher current rating than your estimate (typically 20-30 % higher) to avoid overload, account for dimming and ensure reliability.
In design for TV OEMs or custom systems, check how much current the driver or LED-board is specified for, measure actual draw in production at typical brightness, and ensure cable-routing and trace widths are rated accordingly.
For many TV models:
Smaller TVs (32 inch, 40 inch) with edge-lit LED strips may draw in the range of 0.5-2 A depending on strip length, number of LED rows and brightness.
Mid-sized TVs (49 inch, 55 inch) may draw around 1-4 A under full white backlight condition.
Large TVs (65 inch, 75 inch) with full-array or large edge-lit strips may draw several amps (3-6 A or more) at the backlight supply rail.
Since each LED row or strip adds incremental current, careful design is required to manage power and heat.
When sourcing backlight strips for TVs, it is wise to partner with experienced manufacturers that understand TV panel requirements, offer consistent quality, and provide relevant technical support. For example, StarSharp (www.starsharpcn.com) offers a wide range of led tv backlight strips for sizes from 24 inches up to 85 inches, covering edge-lit and full-array styles. Their product listing includes strips for 32″, 39″, 46″, 55″, 65″, 75″ and 82″ models, which makes them suitable for TV OEMs or aftermarket repair applications.
When working with such suppliers, ensure you specify:
Voltage rating of the strip
LED count and density per strip
Typical current draw or power consumption at full brightness
Thermal ratings and recommended maximum current
Matching run-length and connector type
Compatibility with your panel’s driver board
In summary, the current drawn by a TV backlight LED strip depends on voltage, LED count, brightness setting, and layout. While general LED strips might draw around 1-2 A per metre at 12 V under full-white conditions, TV backlight strips combine multiple rows and specialized design, so total currents of a few amps are common. Using the power formula (I = P/V), deriving from segment-based data, and including safety margin are key steps. Partnering with an experienced supplier such as StarSharp ensures you have reliable components and datasheet support for correct current rating and integration.
Q1: Can I assume current draw is constant regardless of brightness? No. Current draw at full white (all LEDs on at maximum) is the maximum. In normal use brightness may be lower and drawing will be significantly less due to dimming or partial drive.
Q2: Does higher voltage always mean lower current draw? Higher voltage means for the same power you have lower current (I = P/V). But if the strip is designed for higher voltage and same power, yes. In practice the power draw may vary because brightness and LED efficiency differ.
Q3: How much margin should I allow for the power supply? Typically allow at least 20-30 % above the estimated maximum current to account for worst-case brightness, ambient temperature, aging and voltage drops.
Q4: How can I check actual current draw? Use a DC ammeter in series with the backlight supply rail, measure at full white condition, under typical panel brightness settings, and at ambient temperature to ensure worst-case coverage.
Q5: What happens if I under-size the current rating? An undersized power supply may run hot, cause voltage drop, reduce LED brightness, trigger failure, reduce lifespan or cause flicker in the backlight.
