Ripple Current Calculator, Formula, Ripple Current Calculation

Ripple Current Calculator:

Enter the values of output voltage, V_o(V), input voltage, V_i(V), switching frequency, f_s(Hz) and inductance, L_(H) to determine the value of ripple current, I_r(A).

Ripple Current Formula:

Ripple current refers to the AC component superimposed on the DC output of a power supply, commonly observed in power converters such as buck, boost, or buck-boost converters.

It arises due to the switching nature of these power supplies and is significant in determining the efficiency and reliability of electronic systems.

High ripple current can cause excessive heating, reduced component lifespan, and electromagnetic interference (EMI), making its minimization crucial in power supply design.

Ripple current is influenced by factors such as load conditions, switching frequency, and the values of inductors and capacitors in the circuit.

Managing ripple current involves optimizing these parameters to achieve a stable and efficient output.

The ripple current, I_r(A) in amperes is equal to the output voltage, V_o(V) in volts divided by the input voltage, V_i(V) in volts, multiplied by the difference between the input voltage and output voltage, and then divided by the product of the switching frequency, f_s(Hz) in hertz and the inductance, L_(H) in Henry.

The ripple current, I_r(A) = V_o(V) / V_i(V) * (V_i(V) – V_o(V)) / f_s(Hz) * L_(H)

I_r(A) = ripple current in amperes, A.

V_o(V) = output voltage in volts, V.

V_i(V) = input voltage in volts, V.

f_s(Hz) = switching frequency in Hertz, Hz.

L_(H) = inductance in Henry, H.

Ripple Current Calculation:

1. Calculate the ripple current for a buck converter with an output voltage of 5 volts, input voltage of 12 volts, switching frequency of 100 kHz, and inductance of 10 * 10^-6 H:

Given: V_o(V) = 5V, V_i(V) = 12V, f_s(Hz) = 100 * 10³, L_(H) = 10 * 10^-6.

The ripple current, I_r(A) = V_o(V) / V_i(V) * (V_i(V) – V_o(V)) / f_s(Hz) * L_(H)

I_r(A) = 5 / 12 * (12 – 5 ) / 100 * 10³ * 10 * 10^-6

I_r(A) = 0.4167 * 70

I_r(A) = 29.17A.

2. Determine the inductance if the ripple current is 1.5 amperes, the input voltage is 24 volts, the output voltage is 12 volts, and the switching frequency is 200 kHz:

Given: V_o(V) = 12V, V_i(V) = 24V, f_s(Hz) = 200 * 10³, I_r(A) = 1.5A.

The ripple current, I_r(A) = V_o(V) / V_i(V) * (V_i(V) – V_o(V)) / f_s(Hz) * L_(H)

L_(H) = V_o(V) / V_i(V) * (V_i(V) – V_o(V)) / f_s(Hz) * I_r(A)

L_(H) = 12 / 24 * (24 – 12) / 200 * 10³ * 1.5

L_(H) = 0.5 * 12 / 300 * 10³

L_(H) = 0.5 * 0.00004

L_(H) = 0.00002H

L_(H) = 20 * 10^-6H.

Ripple Voltage