LP55281RLEV National Semiconductor, LP55281RLEV Datasheet - Page 8

• Manufacturer Part Number: LP55281RLEV
• Description: BOARD EVAL FOR LP5528 RGB DRIVER
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LP55281RLEV

• Current - Output / Channel: 400mA
• Outputs And Type: 12, Non-Isolated
• Voltage - Output: 5.3V
• Features: USB Interface
• Voltage - Input: 2.7 ~ 5.5V
• Utilized Ic / Part: LP55281
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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Modes of Operation
RESET:
STANDBY:
STARTUP:
BOOST STARTUP: Soft start for boost output is generated in the BOOST STARTUP mode. The boost output is raised in PWM
NORMAL:
In the RESET mode all the internal registers are reset to the default values and the device goes to STANDBY
mode after reset. NSTBY control bit is low after reset by default. Reset is entered always if Reset Register
is written, internal Power On Reset is active, or NRST pin is pulled down externally. The LP55281 can be
reset by writing any data to the Reset Register (address 60H). Power On Reset (POR) will activate during
the device startup or when the supply voltage V
inactivate and the device will continue to the STANDBY mode.
The STANDBY mode is entered if the register bit NSTBY is LOW. This is the low power consumption mode,
when all circuit functions are disabled. Registers can be written in this mode and the control bits are effective
immediately after startup.
When NSTBY bit is written high, the INTERNAL STARTUP SEQUENCE powers up all the needed internal
blocks (VREF, Oscillator, etc.). To ensure the correct oscillator initialization, a 10 ms delay is generated by
the internal state-machine. If the device temperature rises too high, the Thermal Shutdown (TSD) disables
the device operation and STARTUP mode is entered until no thermal shutdown is present.
mode during the 10 ms delay generated by the state-machine. The Boost startup is entered from Internal
Startup Sequence if EN_BOOST is HIGH or from Normal mode when EN_BOOST is written HIGH. During
the 10 ms Boost Startup time all LED outputs are switched off to ensure smooth startup.
During NORMAL mode the user controls the device using the Control Registers. The registers can be written
in any sequence and any number of bits can be altered in a register in one write.
8
DD2
falls below 1.5V. Once V
20201175
DD2
rises above 1.5V, POR will