초록 ▼

Provided is a current-source push-pull DC-DC converter using an active clamp circuit for reusing energy of leakage inductances by not only diodes on a secondary side of a transformer being zero-current switched using a series-resonant full-wave rectifier, but also the active clamp circuit on a prima

Provided is a current-source push-pull DC-DC converter using an active clamp circuit for reusing energy of leakage inductances by not only diodes on a secondary side of a transformer being zero-current switched using a series-resonant full-wave rectifier, but also the active clamp circuit on a primary side of the transformer, which provides a discharge path of the energy stored in the leakage inductances, increases power conversion efficiency even for a wide input voltage range and reduces a switch voltage stress as compared to a conventional current-source push-pull circuit by operating even for a duty ratio below 0.5 by flowing a current of an input inductor through capacitors of the active clamp circuit when both main switches are off.

대표청구항 ▼

What is claimed is: 1. A current-source push-pull DC-DC converter comprising a primary circuit and a secondary circuit divided by a transformer, wherein the primary circuit, which is a current-source push-pull circuit, comprises an input inductor L, two main switches S1 and S2, and an active clamp

What is claimed is: 1. A current-source push-pull DC-DC converter comprising a primary circuit and a secondary circuit divided by a transformer, wherein the primary circuit, which is a current-source push-pull circuit, comprises an input inductor L, two main switches S1 and S2, and an active clamp circuit comprising two sub-switches S3 and S4 and clamp capacitors Cc1 and Cc2; and the secondary circuit is a full-wave output rectifier, wherein when a duty ratio of the main switches S1 and S2 is below 0.5, the current-source push-pull DC-DC converter operates in a non-overlapping mode while one of the main switches S1 and S2 is on, energy is charged in the input inductor L, and the clamp capacitor Cc1 or Cc2 and leakage inductances Lik1 and Lik2 of the transformer resonate. 2. The current-source push-pull DC-DC converter of claim 1, wherein the full-wave output rectifier is a series-resonant full-wave rectifier and comprises two diodes D1 and D2and resonant capacitors Cr1 and Cr2. 3. The current-source push-pull DC-DC converter of claim 1, wherein the full-wave output rectifier is a center-tap full-wave rectifier and comprises two diodes D1 and D2. 4. The current-source push-pull DC-DC converter of claim 1, wherein the full-wave output rectifier is a full-bridge diode circuit. 5. The current-source push-pull DC-DC converter of claim 1, wherein when both of the main switches S1 and S2 are off in the non-overlapping mode, a current, which flowed through the input inductor L and the leakage inductances Lik1 and Lik2 of the transformer, flows through the clamp capacitors Cc1 and Cc2, and energy is not transferred from a primary side of the transformer to a secondary side of the transformer. 6. A current-source push-pull DC-DC converter comprising a primary circuit and a secondary circuit divided by a transformer, wherein the primary circuit, which is a current-source push-pull circuit, comprises an input inductor L, two main switches S1 and S2, and an active clamp circuit comprising two sub-switches S3 and S4 and clamp capacitors Cc1 and Cc2; and the secondary circuit is a full-wave output rectifier, wherein when the duty ratio of the main switches S1 and S2 is greater than 0.5, the current-source push-pull DC-DC converter operates in an overlapping mode while both of the main switches S1 and S2 are on, energy is charged in the input inductor L, a current iL, which flowed through the input inductor L, is divided and flows through the main switches S1 and S2, and energy is not transferred from the primary side of the transformer to the secondary side of the transformer. 7. The current-source push-pull DC-DC converter of claim 6, wherein when one of the main switches S1 and S2 is on and the other one is off in the overlapping mode, the clamp capacitor Cc1 or Cc2, the leakage inductances Lik1 and Lik2 of the transformer, and the resonant capacitors Cr1 and Cr2 of the series-resonant full-wave rectifier are series-resonant, thereby transferring energy to the secondary side of the transformer.