Synchronous converter circuit

• US 4,663,699 A
• Filed: 04/12/1985
• Issued: 05/05/1987
• Est. Priority Date: 04/12/1985
• Status: Expired due to Term

• Current Assignee: Pioneer Magnetics Incorporated
• Original Assignee: Pioneer Magnetics Incorporated
• Inventors: Wilkinson, Bruce L.
• Primary Examiner(s): Wong, Peter S.
• Application Number:
  US06/722,380
• Time in Patent Office: 753 Days
• Field of Search: 363/15-17, 363/39-41, 363/71-72, 363/86, 363/97-98, 363/131-132
• US Class Current: 363/17
• CPC Class Codes: H02M 3/33576 having at least one active switching element at the secondary side of an isolation transformer
• CPC Class Codes: H02M 3/33592 having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A high power factor, regulated synchronous converter for converting 110-volt, rectified, 50-60 Hz alternating current into a direct current output, which has enhanced hold up (energy storage). The circuit includes a half-bridge inverter for converting the half-wave rectified voltage into high frequency alternating current in the range of 20-30 KHz. The high frequency alternating current is coupled through an inductance coil to a half-bridge synchronous regulator/rectifier which produces a direct current output. The energy delivered to the half-bridge synchronous regulator/rectifier is stored in a capacitor, and the voltage across the capacitor may be regulated making energy storage independent of the line voltage. Additional synchronous regulator/rectifiers may be coupled to the circuit to produce additional direct current outputs.

Claims

1. A synchronous converter circuit including:

an input circuit adapted to be connected to the alternating current mains for rectifying the low frequency alternating current therefrom;

an inverter circuit coupled to the input circuit to invert the rectified voltage therefrom into a high frequency current;

said inverter circuit including first and second switches alternately operated at a rate corresponding to the frequency of the high frequency current; and

a synchronous regulator circuit coupled to the inverter circuit and including first and second switches operated in synchronism with the first and second switches of the inverter circuit but at a varying phase relationship therewith to cause the regulator to generate a constant amplitude squarewave signal having a frequency corresponding to the frequency of the high frequency current from the inverter, said first and second switches of said synchronous converter circuit being series connected across the input circuit, and said synchronous converter circuit including first and second capacitors series connected across said switches having a capacity too small to filter out the ripple resulting from the half-wave rectification of the line voltage by said input circuit but providing a low impedance path for the high frequency currents from said synchronous converter circuit; and

said synchronous regulator including first and second capacitors series connected across said first and second switches of said synchronous regulator circuit and whose common junction is connected to the common junction of the first and second capacitors of the synchronous inverter, and which includes a storage capacitor connected across the first and second capacitors of said synchronous regulator across which a constant amplitude high frequency voltage occurs having a frequency corresponding to the frequency of the high frequency current from the synchronous inverter.

2. The synchronous converter circuit defined in claim 1, in which said synchronous regulator includes a storage capacitor across which the constant amplitude voltage appears.

3. The synchronous converter circuit defined in claim 1, and which includes a synchronous rectifier circuit coupled to the synchronous regulator circuit and forming a regulated direct current output in response to the constant amplitude squarewave from the regulator circuit.

4. The synchronous converter circuit defined in claim 3, in which said synchronous rectifier includes first and second switches operated in synchronism with the first and second switches of the synchronous inverter circuit but at a varying phase relationship with respect thereto to regulate the direct current voltage appearing at the output of the rectifier.

5. The synchronous converter circuit defined in claim 3, in which said synchronous rectifier includes a transformer having a high leakage reactance.

6. The synchronous converter circuit defined in claim 1, in which said synchronous inverter is coupled to said synchronous regulator through an inductance coil.