www.awinic.com 9 Copyright © 2020 SHANGHAI AWINIC TECHNOLOGY CO., LTD
Detailed Functional Description
OVERVIEW
AW21018 is an18 channel multi-function LED driver with I2C interface. 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.
OPERATION MODE AND RESET
RESET
Power On Reset
Upon initial power-up, the AW21018 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 VDD 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 VDD ramps up above the threshold voltage VPOR (2.0V) and EN is high, POR is pulled high, meanwhile
the chip enters into initialization mode. The chip needs about 2ms to load the efuse information in initalization
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
configurated. The recommended operation timing is shown as bellow.
VDD
POR
CHIPEN
OSC
Initialization
initial
Standby Active
200μs
EN
..
2ms
Shutdown
INITIAL
MODE
Note: Thechip needsabout 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
Figure 7 Power On Timing
Software Reset
By writing 00h to register RESET (address 70h) in active mode, the software reset is triggered. Then all
registers will be reset to the default value and the chip enters into initialization mode.
After the software reset command is input by I2C, it needs to wait at least 2ms before any other I2C commands
