The Duty Ratio (k) for the Limit of Continuous Conduction & The Average Value of the Output Current
The Duty Ratio (k) for the limit of continuous conduction:
Fig: Operation in discontinuous load current Fig: Operation in continuous load current
- From the waveforms for both continuous and discontinuous load current, it is observed that for a low value of TON, or duty ration, k, time period, T being kept constant the turn off time TOFF is large.
- The output current, i0 may go to zero during this interval, depending on the circuit parameters. Therefore, the limit of continuous conduction is reached, when the minimum current, Imin goes to zero.
- The output (load) current is continuous, if the actual duty ratio, k is more than the above duty ratio, k `, and it becomes discontinuous, if k is lower than the above duty ratio, k`.
The average value of the output current:
The average value of the output (load) current for continuous conduction as obtained from the waveform is obtained as
as the average value of the output is KVS. This is because the average value of L(di/dt) over the time period is zero.