ZHCSGN5B March 2017 – July 2018 LP8863-Q1
PRODUCTION DATA.
The six LED driver channels of the LP8863-Q1 device can automatically support applications using six, five, four, three, and two LED strings. The driver channels can also be tied together in groups of two, three, or six channels. This allows the LP8863-Q1 device to drive three 300-mA LED strings, two 450-mA LED strings, or one 900-mA LED string. The LED strings are always appropriately phase shifted for their string configuration. This reduces the ripple seen at the boost output, which allows smaller output capacitors and reduces audible ringing in the capacitors. Phase shift increases the load frequency, which can move potential capacitor noise above the audible band while still keeping PWM frequency low to support a higher dimming ratio.
When the LP8863-Q1 device is first powered on the string configuration is automatically detected and the phases of each channel configured. The LED string configuration must not be changed unless the LP8863-Q1 is powered off in shutdown state. The string configurations in Table 5 are valid configurations for auto detection. Any other detected configuration defaults to 6 channel / 60 degree mode. The detected string configuration can be read from the LED_STRING_CONF[2:0] register. Tie unused LEDx pins to ground.
CONFIGURATION | LED0 | LED1 | LED2 | LED3 | LED4 | LED5 | AUTOMATIC PHASE SHIFT |
6 channels | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA | 60° |
5 channels | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA | (Tied to GND) | 72° |
4 channels | 150 mA | 150 mA | 150 mA | 150 mA | (Tied to GND) | (Tied to GND) | 90° |
3 channels | 150 mA | 150 mA | 150 mA | (Tied to GND) | (Tied to GND) | (Tied to GND) | 120° |
2 channels | 150 mA | 150 mA | (Tied to GND) | (Tied to GND) | (Tied to GND) | (Tied to GND) | 180° |
3 channels, 300 mA /channel
(tie LED pins together) |
300 mA | 300 mA | 300 mA | 120° | |||
2 channels, 450 mA /channel
(tie LED pins together) |
450 mA | 450 mA | 180° | ||||
1 channel, 900 mA
(tied LED pins together) |
900 mA | None |