Dear Sir/Madam,
I have read the datasheet of TPS548A29 recently.
In 8.2.2.5 Choose the Output Capacitor , the equation to calculate capacitance by under/overshoot are below
I assume that in load step-up condition, a duty cycle is consisting of ton+toff(min). In ON-state, inductor current slope is (Vin-Vo)/L; in OFF time, slope is (-Vo/L). And then using below equation to get the shoot value.
In load step-down condition, low-side MOS is assumed always ON, and inductor current slope is -Vo/L, and then (21) could be acquired.
But in the waveforms part, at load step-down condition, VSW is high for some times. It doesn’t match with equation (21).
In the datasheet, there is minimum ton limit as well as minimum toff limit.
Hope you could help to explain the transient behavior of this device to me. Thanks.
