CS1630/31
6.5 Color Polynomial Coefficient (Q3, Q2, Q1, Q0) – Address 25 - 32
MSB
14
13
12
11
10
9
8
7
6
5
4
3
2
1
LSB
-(23)
22
21
20
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
Coefficients of the color polynomial used to calculate the gain (GAIN ) that controls the current in the white
DR
LED channel based on the current dim level. The value is a two's complement number in the range of
-8.0value<8.0, with the binary point to the right of bit 12. Coefficients Q3, Q2, Q1, and Q0 are distributed in
the gain polynomial:
GAIN
= Q3 D3 + Q2 D2 + Q1 D + Q0
DR
where,
D = the normalized dim value and is 0<D<1.0
GAIN = gain of the channel based on the dim value. The polynomial coefficients should be selected such
DR
that the computed GAIN is always a positive number such that 0<GAIN <4.
DR
DR
Color Polynomial Coefficients, Qxx, are 16-bits in length where Qxx - MSB is the most significant byte and
Qxx-LSB is the least significant byte.
6.6 Gate Drive Duration (GD_DUR) – Address 33
7
6
5
4
3
2
1
0
27
26
25
24
23
22
21
20
GD_DUR sets the maximum gate drive duration for the second stage (flyback, buck, or tapped buck). The reg-
ister value is an unsigned integer in the range of 0value255. The maximum gate drive duration is determined
by:
GD_DUR 8 + 7 50ns
The maximum gate drive duration can be configured from 350ns to 102.35s.
30
DS954F2
APEX [ CIRRUS LOGIC ]
