Because the selection of the inductor affects steady state operation, transient behavior, and loop stability, the inductor is the most important component in power regulator design. There are three important inductor specifications, inductor value, saturation current, and dc resistance (DCR).

The TLV61046A is designed to work with inductor values between 2.2 µH and 22 µH. Follow Equation 2 to Equation 4 to calculate the peak current of the inductor for the application. To calculate the peak current in the worst case, use the minimum input voltage, maximum output voltage, and maximum load current of the application. To have enough design margin, choose the inductor value with -30% tolerance, and a low power-conversion efficiency for the calculation.

In a boost regulator, the inductor dc current can be calculated with Equation 2.

Equation 2.

where

• V_OUT is output voltage
• I_OUT is output current
• V_IN is input voltage
• η is power conversion efficiency, use 80% for most applications

The inductor ripple current is calculated with Equation 3 for an asynchronous boost converter in continuous conduction mode (CCM).

Equation 3.

where

• ΔI_L(P-P) is inductor ripple current
• L is inductor value
• f_SW is switching frequency
• V_OUT is output voltage
• V_IN is input voltage

Therefore, the inductor peak current is calculated with Equation 4.

Equation 4.

Normally, it is advisable to work with an inductor peak-to-peak current of less than 40% of the average inductor current for maximum output current. A smaller ripple from a larger valued inductor reduces the magnetic hysteresis losses in the inductor and EMI. But in the same way, load transient response time is increased. Because the TLV61046A is for relatively small output current application, the inductor peak-to-peak current can be as high as 200% of the average current with a small inductor value, which means the TLV61046A always works in DCM mode. Table 8-2 lists the recommended inductors for the TLV61046A.