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AN4460

Measurements

8.2

Efficiency according to different current setup

Table 4 shows the efficiency reached based on different number of LEDs. All 4 channels are

using the same current. The measure reports the minimum, average and maximum

efficiency for a configured fixed current on all input power voltage range. The current is

calculated based on Table 1 on page 14.

The plots use “y” axis representing the efficiency, expressed as a percentage.

The board configuration is with the LED always ON (“ll x 256" and, if “ed” is enabled, “di

100").

The best efficiency value measure is 98%. Since the board is designed to be “generic” and

supports a wide range of configurations (LED numbers, power voltage range, etc.) the

efficiency reaches 85% in some cases.

The input board power when the PWM outputs are disabled (the LED strings are OFF) is

~300 mW at 12 V and ~600 mW at 48 V.

Figure 17. String efficiency based on different current levels - 3 LEDs for each string

Table 4. Efficiency according to different current when the input voltage changes

Plot

index

Average current

Efficiency

3 LEDs

6 LEDs

10 LEDs

Min. Mean

Max.

Min.

Mean

Max.

Min. Mean Max.

245 mA (lc x 0)

92.8

93.4

94.5

92.5

94.2

95.8

96.0

97.3

98.5

329 mA (lc x 1)

92.1

92.6

94.1

93.7

95.0

96.5

95.5

96.0

96.5

492 mA (lc x 3)

91.1

91.6

92.1

94.4

95.1

96.1

95.9

96.0

96.2

738 mA (lc x 6)

89.2

89.5

89.9

94.1

94.8

95.2

95.3

95.4

95.5

1.065A (lc x 10)

84.9

85.1

85.4

92.3

92.8

93.1

93.4

93.9

94.1

82.0

84.0

86.0

88.0

90.0

92.0

94.0

96.0

12345

3 LED max.

3 LED mean

3 LED min.

AM16717v1

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