SNVSBU8A May 2021 – November 2021 LP5860
PRODUCTION DATA
Analog dimming of LP5860 is achieved by configuring the current gain control. There are several methods to control the current gain of each LED.
The MC is used to set the maximum current IOUT_MAX for each current sink, and this current is the maximum peak current for each LED dot. The MC can be set with 3-bits (8 steps) from 3 mA to 50 mA. When the device is powered on, the MC data is set to default value, which is 15 mA.
For data refresh Mode 1, MC data is effective immediately after new data is updated. For Mode 2 and Mode 3, to avoid unexpected MC data change during high speed data refreshing, MC data must be changed when all channels are off and new MC data is only updated when the 'Chip_EN' bit in Chip_en register is set to 0, and after the 'Chip_EN' returns to 1, the new MC data is effective. 'Down_Deghost' and 'Up_Deghost' in Dev_config3 work in the similar way with MC.
3-BITS MAXIMUM_CURRENT REGISTER | IOUT_MAX | |
---|---|---|
Binary | Decimal | mA |
000 | 0 | 3 |
001 | 1 | 5 |
010 | 2 | 10 |
011 (Default) | 3 (Default) | 15 (Default) |
100 | 4 | 20 |
101 | 5 | 30 |
110 | 6 | 40 |
111 | 7 | 50 |
The LP5860 device is able to adjust the output current of three color groups separately. For each color, the device has 7-bits data in 'CC_Group1', 'CC_Group2', and 'CC_Group3'. Thus, all color group currents can be adjusted in 128 steps from 0% to 100% of the maximum output current, IOUT_MAX.
The 18 current sinks have fixed mapping to the three color groups:
7-BITS CC_GROUP1/CC_GROUP2/CC_GROUP3 REGISTER | RATIO OF OUTPUT CURRENT TO IOUT_MAX | |
---|---|---|
Binary | Decimal | % |
000 0000 | 0 | 0 |
000 0001 | 1 | 0.79 |
000 0010 | 2 | 1.57 |
- - - | - - - | - - - |
100 0000 (default) | 64 (default) | 50.4 (default) |
- - - | - - - | - - - |
111 1101 | 125 | 98.4 |
111 1110 | 126 | 99.2 |
111 1111 | 127 | 100 |
The LP5860 can individually adjust the output current of each LED by using dot current function through DC setting. The device allows the brightness deviations of the LEDs to adjusted be individually. Each output DC is programmed with an 8-bit depth, so the value can be adjusted with 256 steps within the range from 0% to 100% of (IOUT_MAX × CC/127).
8-BIT DC REGISTER | RATIO OF OUTPUT CURRENT TO IOUT_MAX × CC/127 | |
---|---|---|
Binary | Decimal | % |
0000 0000 | 0 | 0 |
0000 0001 | 1 | 0.39 |
0000 0010 | 2 | 0.78 |
- - - | - - - | - - - |
1000 0000 (Default) | 128 (Default) | 50.2 (Default) |
- - - | - - - | - - - |
1111 1101 | 253 | 99.2 |
1111 1110 | 254 | 99.6 |
1111 1111 | 255 | 100 |
In summary, the current gain of each current sink can be calculated as below:
For time-multiplexing scan scheme, if the scan number is N, each LED dot's average current IAVG is shown as below: