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公开(公告)号：JPH11356044A
公开(公告)日：1999-12-24
申请号：JP20477098
申请日：1998-07-21
Applicant: SONY CORP
Inventor： KOBORI KATSUMI , IMAMURA NORITOSHI
Abstract: PROBLEM TO BE SOLVED: To increase the efficiency of a current resonance type switching power supply. SOLUTION: In a switching power supply, switching current is caused to flow in a primary winding L1 of a transformer by alternate turning ON of MOS transistors Q1 , Q2 and then alternating power is transmitted to the secondary side. The alternating power appearing in a secondary winding L2 is rectified in full-wave by diodes D1 , D2 . By connecting resonance elements Cr, Lr to a tertiary winding L3 coupled to the insulation transformer T, the primary side can be turned into a resonance state, thereby this switching power supply becoming a current resonance type switching power supply. Since a leakage inductance of the transformer is not a resonance element, windings of the insulation transformer are tightly coupled. Furthermore, resonance current is not directly turned ON and OFF, and therefore a peak value of the primary current is lowered and a switching loss and a loss due to ON-state resistance can be reduced.
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公开(公告)号：JPH11332233A
公开(公告)日：1999-11-30
申请号：JP20476998
申请日：1998-07-21
Applicant: SONY CORP
Inventor： IMAMURA NORITOSHI , KOBORI KATSUMI
Abstract: PROBLEM TO BE SOLVED: To improve the efficiency of a current resonance switching power supply. SOLUTION: In a switching power supply, a resonance current flows to a primary coil L1 of a transformer and an alternate power is transferred to a secondary side by alternately turning on MOS transistors Q1 and Q2 . Then, with an alternate voltage being generated at a secondary coil L2 , a gate voltage is applied so that a MOS transistor Q3 and a MOS transistor Q4 conduct electricity while the polarity is positive due to a voltage in the secondary coil, and rectified currents id3 and id4 flow to a capacitor C0 via a choke coil Lc for synchronous rectification. When the voltage of a filter capacitor becomes higher than the alternate output voltage when inverted, an inverse current flows to the MOS transistors Q3 and Q4 . However, the inverse current is suppressed by the counterelectromotive force of the choke coil Lc, thus preventing the efficiency of the switching power supply from decreasing.
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公开(公告)号：JPH11299235A
公开(公告)日：1999-10-29
申请号：JP10800698
申请日：1998-04-17
Applicant: SONY CORP
Inventor： IMAMURA NORITOSHI
Abstract: PROBLEM TO BE SOLVED: To improve the efficiency of a current resonant-type switching power supply unit by reducing switching loss, when resonance current is switched. SOLUTION: In this switching power supply unit, when MOS transistors Q1, Q2 are alternately turned on, switching current flows through the primary winding L1 of a transformer, and an AC power is transferred to the secondary side. Alternating voltage generated at a secondary winding L2 is able to turn the primary side into a resonant state by connecting resonance elements C3 (C4), L3 (L4) to the winding L2 which is the output winding of an isolation transformer T which is full-wave-rectified by diodes D1, D2, thus providing current resonant-type switching power supply unit, Since the leakage inductance of the transformer is not made a resonance element, the section between the windings of the isolation transformer can be coupled closely, and since the resonance current is not interrupted directly, the peak value of the primary current drops, thus enabling reduction in switching loss.
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