Datasheet

DS3881
Single-Channel Automotive CCFL Controller
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Table 7. EMI Control Register (EMIC) [Shadowed-EEPROM, F6h]
BIT R/W
FACTORY
DEFAULT
NAME FUNCTION
LAMP OSCILLATOR SPREAD-SPECTRUM MODULATION SELECT
SS1 SS0 SELECTED LAMP FREQUENCY SPREAD
0 R/W 0 SS0
0 0 SPREAD-SPECTRUM DISABLED
0 1 ±1.5%
1 0 ±3.0%
1 R/W 0 SS1
1 1 ±6.0%
2 R/W 0 SSM
Lamp Oscillator Spread-Spectrum Modulation Select
0 = Triangular modulation.
1 = Pseudorandom modulation.
3 ⎯⎯RSVD Reserved. This bit should be set to zero.
4 R/W 0 STEPE
Lamp Frequency Step Enable. Logically ORed with the step invoked.
0 = Lamp operates at nominal frequency.
1 = Frequency step invoked.
LAMP OSCILLATOR FREQUENCY STEP SELECT
FS2 FS1 FS0
SELECTED LAMP
FREQUENCY STEP
(SS0 = 0 AND SS1= 0)
SPREAD-SPECTRUM
MODULATION RATE
(SS0 AND/OR SS1 = 1)
5 R/W 0 FS0
0 0 0 Step Up 1% Lamp Frequency x4
0 0 1 Step Up 2% Lamp Frequency x2
0 1 0 Step Up 3% Lamp Frequency x1
0 1 1 Step Up 4% Lamp Frequency x1/2
6 R/W 0 FS1
1 0 0 Step Down 1% Lamp Frequency x1/4
1 0 1 Step Down 2% Lamp Frequency x1/8
1 1 0 Step Down 3% Lamp Frequency x1/16
7 R/W 0 FS2
1 1 1 Step Down 4% Lamp Frequency x1/32