Contents
How do you calculate voltage ripple?
Peak-to-peak output ripple voltage is the sum of a triwave (created by peak-to-peak ripple current in the inductor times the ESR of the output capacitor) and a square wave (created by the parasitic inductance (ESL) of the output capacitor times ripple current slew rate).
How do you calculate current inductor ripple?
(Ripple current ratio is usually defined as the peak-to-peak value of the inductor current at high line, divided by the maximum load). Their answers typically vary, from a value of 10% up to perhaps 30%. A traditional value of inductor current ripple is 10%, and you will find this in several books.
What is current ripple factor?
Ripple factor is defined as. The ratio of RMS value of an alternating current component in the rectified output to the average value of rectified output. The ripple factor is denoted as γ. It is a dimensionless quantity and always has a value less than unity.
How is the current of a synchronous buck converter calculated?
For the synchronous buck converter, the change in inductor current during the high side MOSFET Q1 on time is equal to the change during the MOSFET’s off time. The inductor current increase is equal to the inductor current decrease. For the above reason, the inductor current ripple can simply be defined as D I L.
How to calculate minimum inductance for buck converter?
Calculating Minimum Inductance: Inductor current ripple is defined as the peak to peak change in current during the on and off time. For the synchronous buck converter, the change in inductor current during the high side MOSFET Q1 on time is equal to the change during the MOSFET’s off time.
What causes the ripple factor in a buck converter?
After LC filtering, assuming corner frequency of LC is much lower than switching frequency, output voltage appears almost pure dc. It can be understood the higher the inductance L is, the lower the capacitance C leads the same output voltage ripple. However, too big inductor causes high volume and high cost.
How to calculate ripple voltage for Buck switch?
The new analytical formulation presented in this application report gives an accurate evaluation of the output ripple as compared to the simplified linear or root-mean square (RMS) approximations often used. In this application report, the analytical model for output voltage waveform and peak-to-peak ripple voltage for buck is derived.