ZXLD1374_11 DIODES [Diodes Incorporated], ZXLD1374_11 Datasheet - Page 25

• Manufacturer Part Number: ZXLD1374_11
• Description: 60V HIGH ACCURACY 1.5A BUCK/BOOST/BUCK-BOOST
• Manufacturer: DIODES [Diodes Incorporated]

ZXLD1374
Document number: DS35032 Rev. 2 - 2
Applications Information
PWM OUTPUT CURRENT CONTROL & DIMMING
The ZXLD1374 has a dedicated PWM dimming input that allows a wide dimming frequency range from 100Hz to 1kHz with
1000:1 resolution; however higher dimming frequencies can be used – at the expense of dimming dynamic range and
accuracy.
Typically, for a PWM frequency of 1kHz, the error on the current linearity is lower than 5%; in particular the accuracy is
better than 1% for PWM from 5% to 100%. This is shown in the graph below:
For a PWM frequency of 100Hz, the error on the current linearity is lower than 2.5%; it becomes negligible for PWM greater
than 5%. This is shown in the graph below:
15.0%
12.5%
10.0%
7.5%
5.0%
2.5%
0.0%
15.0%
12.5%
10.0%
7.5%
5.0%
2.5%
0.0%
Figure 42. LED current linearity and accuracy with PWM dimming at 100Hz
Figure 41. LED current linearity and accuracy with PWM dimming at 1kHz
0%
0%
V
T
f
PWM
10%
IN
A
= 25°C
10%
= 24V
= 100Hz
V
T
f
PWM
(Continued)
A
IN
20%
= 25°C
= 24V
20%
= 1kHz
60V HIGH ACCURACY 1.5A BUCK/BOOST/BUCK-BOOST
30%
30%
40%
40%
www.diodes.com
PWM duty cycle
PWM duty cycle
Normalized LED
Current Error
25 of 37
50%
50%
LED DRIVER CONVERTER WITH AEC-Q100
I
LED
Normalized LED
Current Error
60%
60%
70%
70%
I
LED
Diodes Incorporated
80%
80%
A Product Line of
90%
90%
100%
100%
1500
1250
1000
750
500
250
0
1500
1250
1000
750
500
250
0
© Diodes Incorporated
ZXLD1374
March 2011