# Maximum Average Current of Internal LEDs ADPD188

Hi,

what is the maximum (average) current rating for the internal green LEDs in the chip? When using normal mode with 2µs pulse width and 19µs period it can not exceed 40mA even with 370mA peak current. But in float mode (synchronous LED measurement) with 31µs pulse width the on/off-ratio of the LED could be much higher. Where is the limit (we have very weak signals) - in 40mA average or higher?

Regards
Dirk

• Hi Dirk,

The peak CW (always on current) of the LED by the vendor is 30mA. With 2µs pulse width, the average current is below 30mA even with 370mA peak current due to the small duty cycle of the pulse.

Float mode allows wider pulse hence a higher average current can be achieved with relatively high peak current.

Regards,

Glen B.