LM3530UME-40/NOPB National Semiconductor, LM3530UME-40/NOPB Datasheet - Page 16

• Manufacturer Part Number: LM3530UME-40/NOPB
• Description: IC LED DRVR PROGRAM I2C 12USMD
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM3530UME-40/NOPB

• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 500kHz
• Voltage - Supply: 2.7 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 12-UFBGA
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: Adjustable
• Led Driver Application: LED Backlighting, Portable Electronics
• No. Of Outputs: 1
• Output Current: 29.5mA
• Output Voltage: 40V
• Input Voltage: 2.7V To 5.5V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Other names: LM3530UME-40TR

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ZONE BOUNDARY SETTINGS
Registers 0x60, 0x61, 0x62, and 0x63 set the 4 zone bound-
aries (thresholds) for the ALS inputs. These 4 zone bound-
aries create 5 brightness zones which map over to 5 separate
brightness zone targets (see
boundary register can set a threshold from typically 0 to 1V
with linear step sizes of approximately 1/255 = 3.92mV. Ad-
ditionally, each zone boundary has built in hysteresis which
can be either lower or higher then the programmed Zone
Boundary depending on the last direction (either up or down)
of the ALS input voltage.
Figure
FIGURE 7. Ambient Light Input to Backlight Transition
4). Each 8–bit zone
FIGURE 8. Perceived Brightness Change Time
16
ZONE BOUNDARY TRIP POINTS AND HYSTERESIS
For each zone boundary setting, the trip point will vary above
or below the nominal set point depending on the direction (ei-
ther up or down) of the ALS input voltage. This is designed to
keep the ALS input from oscillating back and forth between
zones in the event that the ALS voltage is residing near to the
programmed zone boundary threshold. The Zone Boundary
Hysteresis will follow these 2 rules:
1.
If the last zone transition was from low to high, then the
trip point (V
V
ZONE_BOUNDARY
TRIP
30086687
30086688
) will be V
is the zone boundary set point as
ZONE_BOUNDARY
- V
HYST
/2, where