[FAQ] TPS922051: How to design the shunt resistor Rlk_comp for TPS922051/0

Below are tips and explanations on how to design the shunt resistor Rlk_comp.

As shown from below schematic, an optional resistor is chosen for Rlk_comp to compensate the CSP+CSN common-mode leakage current and avoid it passing through LEDs.

SW/CSP/CSN leakage path:

The SW/CSN/CSP leakage current path before and after adding Rlk_comp is shown below which shows that the Rlk_comp can help to compensate the CSP+CSN common mode leakage current and avoid it passing through LEDs.

How to design Rlk_comp:

Try-and-error in evaluation. Measure the LED voltage and leakage current when the LED is off. Then calculate the shunt resistor. It is effective but needs some try-and-error process.