Datasheet

DS_INLC10AQ Revision 1.0_B

Inova Semiconductors Confidential

Page 22 of 35

4.2

PWM Units

4.2.1 Basic Mode of Operation

The LED controller device incorporates three independent PWM channels, one for each LED.

Figure 16

– PWM signal

The resolution is 12 bit. The supported duty cycles are 0/4096 to 4095/4096. The nominal PWM output

frequency is 16MHz ⁄ 215 = 488.3Hz. The frequency is reduced to the half or the quarter of this frequency

with low duty cycles. This ensures a minimum on-

time of 2μs for the LEDs. The minimum output frequency

is 122Hz. The output frequency is not derived from the actual PWM duty cycle but from the RGB value

received from the host. As the DIM command also has impact to the LED intensity, it is accounted for as

well. The actual relationship is given in the following table.

DIM

RGB

PWM Frequency

Unit

Min.

Typ.

Max.

0

8

… 255

341.6

488

634.4

Hz

4

… 7

170.8

244

317.2

Hz

0

… 3

85.4

122

158.6

Hz

1

16

… 255

341.6

488

634.4

Hz

8

… 15

170.8

244

317.2

Hz

0

… 7

85.4

122

158.6

Hz

2

32

… 255

341.6

488

634.4

Hz

16

… 31

170.8

244

317.2

Hz

0

… 15

85.4

122

158.6

Hz

3

64

… 255

341.6

488

634.4

Hz

32

… 63

170.8

244

317.2

Hz

0

… 31

85.4

122

158.6

Hz

Table 20

– DIM parameter relationships between RGB parameters and PWM frequencies

The output frequency is determined independently for each of the PWM channels.