BM77 - What is the LED1 pin (pin 30) current rating?
For the BM77, what is the LED1 pin (pin 30) current rating?
LED1 pin is a sink only pin. The amount of current it will sink is configurable depending on the brightness you need. To configure the sink current at pin LED1 you need to access address 0xEE of the configuration EEPROM. Bits(3:0) control sink current for LED1, while Bits(7:4) control sink current for LED2. The configuration resolution is 4-bits. This is the nybble description:
- b0000 for 1 mA
- b0001 for 2 mA
- … b1111 for 16 mA
The key design point here is you need to find an LED that can handle forward current from 1 mA to 16 mA to fully utilize the brightness control feature.