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DETAILED FUNCTIONAL DESCRIPTION
OVERVIEW
AW21009 is a 9 channel multi-function LED driver. Each channel has individual 8-bit DC current setting for
color-mixing and maximum 12-bit PWM resolution for brightness control. The global current of each channel
is recommended to be 40mA configured via register and external Resistor REXT.
Phase-control, spread spectrum technology and slew rate control are utilized to reduce EMI and audible noise
caused by MLCC. Output current of each LED can be controlled by one pattern or be configured independently.
The integrated pattern controller provides breathing or group dimming control. The breathing mode includes
auto breathing and manual control mode. All breathing parameters are configurable including rising/falling
slope, on/off time, repeat times and brightness.
AW21009 can be turned off with minimum current consumption by either pulling the EN pin low or using the
software shutdown feature.
OPERATION MODE AND RESET
RESET
Power On Reset
Upon initial power-up, the AW21009 is reset by internal power-on-reset, and all registers are reset to default
value, and the chip is shut down.
Once the supply voltage VCC drops below the threshold voltage VPOR(2.0V), the power-on-reset will reset the
chip again. By reading the bit PUST of the register UVCR (address 60h), whether the chip has been reset can
be detected.
When the VCC ramps up above the threshold voltage VPOR (2.0V) and EN is ‘1’, POR is pulled high, meanwhile
the chip enters into initialization mode. The chip needs about 2ms to load the OTP information in initialization
mode. After initialization, it works in lower-power mode. About 200μs delay is required after CHIPEN is pulled
up, otherwise, internal OSCCLK may work incorrectly. Only in low-power and active mode, registers could be
configured. The recommended operation timing is shown as bellow.
VCC
POR
CHIPEN
OSC
Initialization
initial
Standby Active
200μs
EN
..
2ms
Shutdown
INITIAL
MODE
Note: Thechip needs about 2ms for
initalization after power on
(bit CHIPEN of GCR register)
Note: Recommend CHIPEN=1 after Initial
Note: OSC operates stable,which needs
200μs after CHIPEN=1
Internal registers are configurable
Configuring
Time
