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SiC-Schottky-Slide14

There are two conduction modes of the boost inductor in PFC boost converter operation - Discontinuous Conduction Mode (DCM) and Continuous Conduction Mode (CCM). In DCM, the boost inductor current will reach zero at each switching cycle, as shown in the graph. In order to achieve the same level of average power, peak current in the boost inductor must be much higher than the average current level. Even though the control loop is easy to design, the high switching current will result in higher electromagnetic interference (EMI), and the power devices have to sustain high electric stresses. DCM operation is usually used in 250W and below SMPS. Since the current reaches zero at each switching cycle, there is no switching current at the diode turn-off interval. Therefore, SiC Schottky diodes will not be beneficial to DCM operation.

PTM Published on: 2011-10-26