SNVA958 April 2020 LP8863-Q1
The LP8863-Q1 device is an automotive 6-channel backlighting LED driver, which defaults to phase shift mode. When the device is powered on, the string configuration is automatically detected and the phases of each channel configured. For example, if four strings are connected, the LED outputs are phase shifted by 90° (= 360 / 4); if 6 strings are connected, the LED outputs are phase shifted by 60° (=360/6). The LED strings are always appropriately phase shifted for their string configuration. This reduces the ripple of the boost output, and increases the load frequency which can move potential capacitor noise above the audible band.
The string configurations in Table 1 are valid configurations for auto detection. Any invalid configurations are NOT allowed to be used. The detected configuration can be read from AUTO_LED_STRING_CFG in AUTO_DETECT_DIAGNOSTICS register.
| Configuration | LED0 | LED1 | LED2 | LED3 | LED4 | LED5 | Detected LED String Configuration
(AUTO_LED_STRING_CFG) |
Phase Shift |
|---|---|---|---|---|---|---|---|---|
| 6 channels | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA | 0h = 6 separate strings | 60° |
| 5 channels | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA | GND | 1h = 5 separate strings | 72° |
| 4 channels | 150 mA | 150 mA | 150 mA | 150 mA | GND | GND | 2h = 4 separate strings | 90° |
| 3 channels | 150 mA | 150 mA | 150 mA | GND | GND | GND | 3h = 3 separate strings | 120° |
| 2 channels | 150 mA | 150 mA | GND | GND | GND | GND | 4h = 2 separate strings | 180° |
| 3 channels | 300 mA | 300 mA | 300 mA | 5h = outputs connected in groups of 3 to drive 2 strings | 120° | |||
| 2 channels | 450 mA | 450 mA | 6h = outputs connected in groups of 2 to drive 3 strings | 180° | ||||
| 1 channel | 900 mA | 7h = all outputs connected together to drive one string | None | |||||