LP5520TL/NOPB National Semiconductor, LP5520TL/NOPB Datasheet - Page 5

• Manufacturer Part Number: LP5520TL/NOPB
• Description: IC LED DRIVER RGB 25-USMD
• Manufacturer: National Semiconductor
• Series: PowerWise®r
• Type: RGB LED Driverr

Specifications of LP5520TL/NOPB

• Constant Current: Yes
• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 3
• Internal Driver: Yes
• Type - Primary: Backlight, Light Management Unit (LMU)
• Type - Secondary: RGB, White LED
• Frequency: 1.22kHz, 19.52kHz
• Voltage - Supply: 2.9 V ~ 5.5 V
• Voltage - Output: 5 V ~ 20 V
• Mounting Type: Surface Mount
• Package / Case: 25-MicroSMD
• Operating Temperature: -30°C ~ 85°C
• Current - Output / Channel: 60mA
• Internal Switch(s): Yes
• Efficiency: 87%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LP5520TLTR

Block Diagram
Modes of Operation
LP5520 has three different operating modes: Manual mode,
Automatic mode and Stand-Alone mode. The Automatic
mode has two sub modes, normal mode and sequential
mode. In manual and automatic modes the chip is controlled
MANUAL MODE
In the manual mode the automatic LED intensity adjustment
is not in use. The internal PWM control is disabled and the
LEDs are driven with DC current. The user can set the LED
currents through the serial port using three Current Control
registers, current_control_R/G/B, and use the external
PWM control inputs to adjust LED intensities if needed. There
is an independent PWM control pin for each output. If PWM
control is not used, the PWMR, PWMG and PWMR inputs
should be tied to the V
the internal PWM control are unavailable in manual mode
(logarithmic brightness control from PWM Control register,
temperature compensation, fading, sequential mode).
<RGB_auto>
(RBG control bit 3)
0
1
1
DDIO
<seq_mode[0:1]>
(RBG control bits 6 and 7)
. All the functions implemented with
01, 10 or 11
00
00
LP5520 Operating Mode
Manual mode
Automatic mode, normal operation (overlapping)
Automatic mode, sequential operation with 2, 3 or 4 pulses per sequence
5
through the serial interface. In standalone mode only BRC
input needs to be controlled and all registers have the default
values.The modes are controlled according to the following
table.
AUTOMATIC MODE
In the automatic mode the LED intensities are controlled with
the 12-bit PWM values obtained from the EEPROM memory
according to the temperature information. PWM values are
stored at 16°C intervals for the –40 to 120°C temperature
range, and the PWM values for the intermediate temperatures
are linearly interpolated.
When creating white light from a RGB LED, the intention is to
program PWM values, which keep the individual LED inten-
sities constant in all temperatures. For possible other appli-
cations, other kind of PWM behavior can be programmed, and
also the variable can be other than temperature if the sensor
is changed to e.g. a light sensor.
12-bit ADC is used for the measurements. The ADC has two
inputs S1_IN and S2_IN. The temperature measurement re-
sult from the S1_IN input is converted to EEPROM address
20186111
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