SLUAAB9A March 2021 – December 2021 UCC25800-Q1
The LLC converter is able to support multiple secondary-side windings and their output voltages are proportional to the transformer turns-ratio. Given the complicated transformer leakage inductance distribution, the primary-side resonant is preferred in this configuration, as shown in Figure 7-2. Since this uses primary-side resonant, the primary-side capacitors are the resonant capacitor and the secondary-side series capacitors are the DC-blocking capacitor for the voltage doubling purpose. The voltage-regulation tolerance is not as good as secondary-side resonant. Besides, all the secondary-side windings are on the same transformer, the noise coupling among these outputs needs to be considered.