Comprehensive Guide to TPS62420 Feedback Network Design
The TPS62420 is a high-efficiency synchronous dual step-down DC-DC converter optimized for battery-powered applications. Achieving precise output voltages requires accurate calculation and selection of external feedback resistor networks connected between the output, the feedback pin (FB), and ground. Because the internal reference voltage ($V_{REF}$) is fixed at 0.6V, designing a stable voltage divider network directly dictates system performance, efficiency, and steady-state DC accuracy.
Formula Used
The mathematical relationship governing the output voltage relative to the feedback network components is derived from the voltage divider rule combined with the internal reference comparator:
$$V_{OUT} = V_{REF} \times \left(1 + \frac{R_1}{R_2}\right)$$
To compute the required top feedback resistor ($R_1$) given a desired target output voltage and a chosen bottom resistor ($R_2$), the formula is algebraically rearranged as follows:
$$R_1 = R_2 \times \left(\frac{V_{OUT}}{V_{REF}} - 1\right)$$
How to Use This Calculator
- Input Target Output Voltage: Enter your desired regulated output voltage (must be greater than 0.6V).
- Specify Bottom Resistor (R2): Input a baseline resistance value for R2, such as 10kΩ.
- Select E-Series Preference: Choose between standard E12 or E24 resistor availability grids.
- Toggle Advanced Options: Enable tolerance limits or choose temperature coefficients to check operational stability.
- Click Calculate: Review generated exact values, standard selections, error percentages, and power dissipation instantly.