Gate drive duration (gd_dur) – address 33 – Cirrus Logic CS1631 User Manual
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6.5 Color Polynomial Coefficient (Q3, Q2, Q1, Q0)
–
Address 25 - 32
Coefficients of the color polynomial used to calculate the gain (GAIN
DR
) that controls the current in the white
LED channel based on the current dim level. The value is a two's complement number in the range of
-8.0
value<8.0, with the binary point to the right of bit 12. Coefficients Q3, Q2, Q1, and Q0 are distributed in
the gain polynomial:
where,
D = the normalized dim value and is 0<D<1.0
GAIN
DR
= gain of the channel based on the dim value. The polynomial coefficients should be selected such
that the computed GAIN
DR
is always a positive number such that 0<GAIN
DR
<4.
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
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 0
value255. The maximum gate drive duration is determined
by:
The maximum gate drive duration can be configured from 350ns to 102.35
s.
MSB
14
13
12
11
10
9
8
7
6
5
4
3
2
1
LSB
-(2
3
)
2
2
2
1
2
0
2
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
2
-8
2
-9
2
-10
2
-11
2
-12
7
6
5
4
3
2
1
0
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
GAINDR
Q
3
=
D
3
Q2 D
2
Q1 D
Q0
+
+
+
GD_DUR 8
7
+
50
ns