LP5521TM/NOPB National Semiconductor, LP5521TM/NOPB Datasheet - Page 19

• Manufacturer Part Number: LP5521TM/NOPB
• Description: IC LED DRIVER RGB 25-USMD
• Manufacturer: National Semiconductor
• Series: PowerWise®r
• Type: RGB LED Driverr

Specifications of LP5521TM/NOPB

• Constant Current: Yes
• Topology: PWM, Switched Capacitor (Charge Pump)
• Number Of Outputs: 3
• Internal Driver: Yes
• Type - Primary: Backlight, Light Management Unit (LMU)
• Type - Secondary: RGB
• Frequency: 1.25MHz
• Voltage - Supply: 2.7 V ~ 5.5 V
• Voltage - Output: 4.55V
• Mounting Type: Surface Mount
• Package / Case: 20-MicroSMD
• Operating Temperature: -30°C ~ 85°C
• Current - Output / Channel: 25.5mA
• Internal Switch(s): Yes
• Efficiency: 95%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LP5521TMTR

LED Controller Programming Commands
LP5521 has three independent programmable channels (R,
G, B). Trigger connections between channels are common for
all channels. All channels have own program memories for
storing complex patterns. Brightness control and patterns are
done with 8-bit PWM control (256 steps) to get accurate and
smooth color control.
Program execution is timed with 32 768 Hz clock. This clock
can be generated internally or external 32 kHz clock can be
connected to CLK_32K pin. Using external clock enables
synchronization of LED timing to this clock rather than internal
X means do not care whether 1 or 0.
Ramp/Wait
Ramp command generates a PWM ramp starting from current
value. At each ramp step the output is incremented by one.
Time for one step is defined with Prescale and Step time bits.
Minimum time for one step is 0.49 ms and maximum time is
63 x 15.6 ms = 1 second/step, so it is possible to program very
fast and also very slow ramps. Increment value defines how
many steps are taken in one command. Number of actual
steps is Increment + 1. Maximum value is 127d, which corre-
sponds to half of full scale (128 steps). If during ramp com-
mand PWM reaches minimum/maximum (0/255) ramp com-
mand will be executed to the end and PWM will stay at
Go to Start
Ramp/Wait command
Command
Set PWM
Branch
Trigger
15
Ramp
0
Wait
End
Increment
Step time
Prescale
scale
Name
Pre-
Sign
14
15
0
0
0
1
1
1
13
scale
Pre-
14
1
0
0
1
1
12
13
1
0
1
Value(d)
11
Step time
0-127
1-63
12
Int
0
1
0
1
Wait for trigger on channels 5-0
Reset
10
11
Step time
0
0
Loop count
10
9
One ramp increment done in (step time) x (clock after prescale) Note: 0
Divides master clock (32 768Hz) by 16 = 2048 Hz, 0.49 ms cycle time
Divides master clock (32 768Hz) by 512 = 64 Hz, 15.6 ms cycle time
The number of steps is Increment + 1. Note: 0 is a wait instruction.
9
8
19
Sign
8
7
clock. Selection of the clock is made with address 08H bits
INT_CLK_EN and CLK_DET_EN. See External Clock Detec-
tion for details.
Supported commands are listed in the table below. Com-
mand compiler is available for easy sequence program-
ming. With Command compiler it is possible to write
sequences with simple ASCII commands, which are then
converted to binary or hex format. See application note
"LP5521 Programming Considerations" for examples of
Command compiler usage.
minimum/maximum. This enables ramp command to be used
as combined ramp and wait command in a single instruction.
Ramp command can be used as wait instruction when incre-
ment is zero.
Setting register 00H bit LOG_EN sets the scale from linear to
logarithmic. When LOG_EN = 0 linear scale is used, and
when LOG_EN = 1 logarithmic scale is used. By using loga-
rithmic scale the visual effect of the ramp command seems
linear to the eye.
Sign
7
0
6
means Set PMW command.
Decrease PWM output
Increase PWM output
6
0
x
5
Description
Send trigger on channels 5-0
X
5
0
Increment (number of steps)
4
PWM Value
Step / command number
4
0
Increment
3
3
0
2
2
0
1
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1
0
0
X
0
0