DS3881E+C Maxim Integrated Products, DS3881E+C Datasheet - Page 13

• Manufacturer Part Number: DS3881E+C
• Description: IC CCFL CONTROL 24TSSOP
• Manufacturer: Maxim Integrated Products
• Type: CCFL Controllerr

Specifications of DS3881E+C

• Frequency: 40 ~ 100 kHz
• Current - Supply: 12mA
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -40°C ~ 105°C
• Package / Case: 24-TSSOP
• Operating Supply Voltage: 5 V
• Maximum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: + 105 C
• Supply Current: 12 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: DS3881E+; DS3881E+

At the beginning of each lamp burst, the DS3881 pro-
vides a soft-start that slowly increases the MOSFET
gate-driver duty cycle (see Figure 6). This minimizes
the possibility of audible transformer noise that could
result from current surges in the transformer primary.
The soft-start length is fixed at 16 lamp cycles, but the
soft-start ramp profile is programmable through the
four soft-start profile registers (SSP1/2/3/4) and can
be adjusted to match the application. There are seven
Figure 6. Digital PWM Dimming and Soft-Start
LAMP CURRENT
DPWM SIGNAL
SOFT-START PROFILE REGISTER
Single-Channel Automotive CCFL Controller
MOSFET GATE DRIVERS
SOFT-START
LAMP CURRENT
LAMP CYCLE
GA1/GB1
22.5Hz TO 440Hz
1
SSP1. 0-3
PROGRAMMABLE SOFT-START PROFILE WITH INCREASING MOSFET PULSE WIDTHS OVER
A 16 LAMP CYCLE PERIOD RESULTS IN A LINEAR RAMP IN LAMP CURRENT.
DPWM Soft-Start
2
____________________________________________________________________
3
SSP1. 4-7
4
SSP2. 0-3
5
6
different driver duty cycles to select from to customize
the soft-start ramp (see Tables 4a and 4b). The avail-
able duty cycles range from 0% to 19% in ~3% incre-
ments. In addition, the MOSFET duty cycle from the
last lamp cycle of the previous burst can be used as
part of the soft-start ramp by using the most recent
value duty cycle code. Each programmed MOSFET
gate duty cycle repeats twice to make up the 16 soft-
start lamp cycles.
7
SSP2. 4-7
8
SOFT-START (EXPANDED)
SSP3. 0-3
9
10
11
SSP3. 4-7
12
SSP4. 0-3
13
14
SSP4. 4-7
15
16
13