LED Driver

KC24H-R Series

2014.02.28-A/3

Page 5 of 6

MORNSUN Guangzhou Science & Technology Co., Ltd. reserves the copyright and right of final interpretation

5. PWM dimming control

PWM Control Signal

0

1

0

1

0

1

0

1

0

1

PWM Control Signal

Output Current

Output Current(LED turned on)

Output Current(LED turned off)

PWM Control Signal

For PWM dimming signals with a certain frequency, the output current of the driver is related to the duty ratio of PWM signal. Refer to the

formula for the calculation method:

T

=

(DT-0.8)

Where, Io_set represents required output current (mA); D represents the duty ratio (%) of PWM signal; T represents the period (ms) of PWM

signal; and Io_norm represents the rated output value (mA) of the driver.

Note: The above formula is for reference only; and deviation of output current may exist due to various loads. The min. conducted time of PWM signal shallnot

be less than 0.8ms, or the product will be in abnormal operation; in case of low voice from the driver during PWM dimming, it is normal since the PWM

dimming frequency is within the auditory frequency range of human ears (20Hz-20KHz in general). To prevent seeing flash of the LED by human eyes, it is

suggested to set the PWM dimming frequency between 100-200Hz.

PWM curve(Vin=24V,5LEDs):

KC24H-350RX3

KC24H-500RX3

KC24H-700RX3

50

100

150

200

250

300

350

400

10 30 50 70 90 100 120 140 150 170 190 200 220 250

PWM Dimming Frequency (Hz)

Fig. 6 Output current VS PWM dimming frequency (D=50%)

KC24H-350RX3

KC24H-500RX3

KC24H-700RX3

0

100

200

300

400

500

600

20

30

40

50

60

70

80

Dimming Duty Ratio (%)

Fig. 7 Output current VS Dimming duty ratio(f=200Hz)

6. Analogue dimming and typical application

1st LED

Last LED

KC24H-xxxRX3

+Vin

GND

15K

6K8

On/Off

(Optional)

0-10V

1

4

6

5

3

2

Fig. 8 Analogue dimming circuit

Voltage Control(0-15V max)

Analogue Input Voltage

0.2V

1V

2V

3V

4V

5V 15V

0%

100%

Fig. 9 Analogue input voltage and output current

7. The voltage drop of all LEDs in the datasheet is 3.3-3.8V，during actual application, the number of LEDs

can be confirmed based on the actual voltage drop and output voltage of LEDs.

8. This product does not support hot-Plug use.

9. For more information Please find the application notes on www.mornsun-power.com