lp5527tlx National Semiconductor Corporation, lp5527tlx Datasheet - Page 6

• Manufacturer Part Number: lp5527tlx
• Description: Tiny Led Driver For Camera Flash And 4 Leds With I2c Programmability, Connectivity Test And Audio Synchronization
• Manufacturer: National Semiconductor Corporation

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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 a low current
NORMAL:
In the reset mode all the internal registers are reset to the default values. Reset is entered always if input
NRST is LOW or internal Power On Reset (POR) is active. Power on reset will activate during the chip
startup or when the supply voltage V
and the chip will continue to the STANDBY mode. NSTBY control bit is low after POR by default.
The standby mode is entered if the register bit NSTBY is LOW and reset is not active. 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 start up.
When NSTBY bit is written high, the internal startup sequence powers up all the needed internal blocks
(V
internal state-machine. If the chip temperature rises too high, the thermal shutdown (TSD) disables the chip
operation and startup mode is entered until no thermal shutdown event is present.
PWM 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 normal mode the user controls the chip 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.
REF
, Oscillator, etc.). To ensure the correct oscillator initialization, a 10 ms delay is generated by the
DD2
falls below 1.5V. Once V
6
DD2
rises above 1.5V, POR will inactivate
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