An external resistor divider adjusts the output voltage of the TPS65131-Q1 boost converter stage. Connect this divider to the FBP pin. The typical value of the voltage at the FBP pin is the reference voltage, which is 1.213V. The maximum recommended output voltage at the boost converter is 15V. To achieve appropriate accuracy, the current through the feedback divider should be about 100 times higher than the current into the FBP pin. Typical current into the FBP pin is 0.05µA, and the voltage across R2 is 1.213V. Based on those values, the recommended value for R2 should be lower than 200kΩ in order to set the divider current at 5µA or higher.

Calculate the value of resistor R1, as a function of the needed output voltage (V_POS), with Equation 1:

Equation 1.

In this example, with R2 = 130kΩ, choose R1 = 1MΩ to set V_POS = 10.5V.