LP5521TM/NOPB National Semiconductor, LP5521TM/NOPB Datasheet - Page 20

• 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

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Application example:
For example if following parameters are used for ramp:
•
•
•
•
Set PWM
Set PWM output value from 0 to 255. Command takes sixteen
32 kHz clock cycles (= 488 μs). Setting register 00H bit
LOG_EN sets the scale from linear to logarithmic.
Go to start
Go to start command resets Program Counter register and
continues executing program from the 00H location. Com-
Branch
When branch command is executed, the 'step number' value
is loaded to PC and program execution continues from this
location. Looping is done by the number defined in loop count
End
End program execution, resets the program counter and sets
the corresponding EXEC register to 00b (hold). Command
takes sixteen 32 kHz clock cycles.
Set PWM command
Go to start command
Branch command
End command
15
15
15
15
Prescale = 1 => cycle time = 15.6 ms
Step time = 2 => time = 15.6 ms x 2 = 31.2 ms
Sign = 0 => rising ramp
Increment = 4 => 5 cycles
0
0
1
1
14
14
14
14
1
0
0
1
step number
loop count
13
13
13
13
0
0
1
0
Name
12
12
12
12
int
0
0
reset
11
11
11
11
0
0
Value(d)
0-63
0-15
Example of 2 sequential ramp commands.
Loop count
10
10
10
10
0
0
X
The number of loops to be done. 0 means infinite loop.
The step number to be loaded to program counter.
X
9
0
9
0
9
9
X
8
0
8
0
8
8
20
X
7
7
0
7
7
Ramp command will be: 0100 0010 0000 0100b = 4204H
If current PWM value is 3, and the first command is as de-
scribed above and next command is a ramp with otherwise
same parameters, but with Sign = 1 (Command = 4284H), the
result will be like in the following figure:
mand takes sixteen 32 kHz clock cycles. Note that default
value for all program memory registers is 0000H, which is Go
to start command.
parameter. Nested looping is supported (loop inside loop).
The number of nested loops is not limited. Command takes
sixteen 32kHz clock cycles.
Description
X
X
6
6
0
6
6
5
5
0
5
X
5
X
PWM value
X
X
4
4
0
4
4
X
3
3
0
3
3
20186219
Step number
X
2
2
0
2
2
X
1
1
0
1
1
0
0
0
0
0
X