Questions about the MAX16826 Operation Is this part only for high power LED or can it be used for low power LED as well? What are the four resistors for? How much current are you supposed to get through each LED? Is there a way to limit this current? Answers: The current in each string is determined by the current sense regulation voltage and the resistor value in the source of each of the sink FETs. The current sense regulation voltage default value is 318mV, and can be programmed in 1.72mV steps from 318mA to 97mV with registers 00k to 03h. You can use a combination of changing the resistor value and the sense regulation voltage to meet your current goals. The voltage at the drain of the sink FETs is used to determine if a fault has occurred in the string; The DR_ inputs are read by the ADC and the levels defined in the datasheet indicate fault levels. Resistors R20, R22, R24, and R26 set up dividers with R21, R23, R25, and R27to set the input to the DR inputs so that the voltage values can be read back and faults detected. R32, R33, R34, and R35 should be 237k. They set to voltage if the LED string is open and the current is set to zero and helps to prevent the voltage on the DR pins form exceeding their absolute max of 6V.

MAX16826 Operation

Questions about the MAX16826 Operation

Is this part only for high power LED or can it be used for low power LED as well?

What are the four resistors for?

How much current are you supposed to get through each LED? Is there a way to limit this current?

Answers:

The current in each string is determined by the current sense regulation voltage and the resistor value in the source of each of the sink FETs. The current sense regulation voltage default value is 318mV, and can be programmed in 1.72mV steps from 318mA to 97mV with registers 00k to 03h. You can use a combination of changing the resistor value and the sense regulation voltage to meet your current goals.
The voltage at the drain of the sink FETs is used to determine if a fault has occurred in the string; The DR_ inputs are read by the ADC and the levels defined in the datasheet indicate fault levels. Resistors R20, R22, R24, and R26 set up dividers with R21, R23, R25, and R27to set the input to the DR inputs so that the voltage values can be read back and faults detected.
R32, R33, R34, and R35 should be 237k. They set to voltage if the LED string is open and the current is set to zero and helps to prevent the voltage on the DR pins form exceeding their absolute max of 6V.