Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of dc power input into dc power output
  • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
  • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
  • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of dc power input into dc power output
  • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
  • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
  • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
  • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
  • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
  • H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
  • H02M3/33592—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer

Definitions

• the present invention relates to a DC-DC converter circuit, and in particular to a synchronous flyback converter circuit for operation in a continuous mode.
• flyback topology One way of obtaining a suitable rectifier circuit is to use flyback topology.
• a flyback topology a primary side stores magnetic energy in a magnetisable core or the like during a charging interval . The energy is then fed to a secondary side during the so called flyback interval .
• the main advantage of a power rectifier circuit having a flyback topology compared to other rectifier circuits is its simple construction, which makes it cheap to manufacture.
• flyback converters can be divided into two different kinds:
• a conventional flyback converter comprises, on the primary side, a primary winding of a transformer and a switch, and on the secondary side a secondary winding of the transformer connected to a diode and an output capacitor over which a load can be connected.
• Such a converter has a large voltage drop over the diode.
• the voltage drop over the diode becomes a significant part of the overall voltage, which makes the power converter inefficient for such low voltage applications.
• a FET transistor which has a much lower voltage drop can be used on the secondary side .
• the FET transistor can for example be directly connected to an auxiliary winding arranged in series with the secondary winding of the transformer.
• a converter designed according to these principles is for example described in the co-pending Swedish patent application No. 9801595-1.
• a drive pulse is generated by an inverting buffer circuit, which is fed from the output voltage.
• the drive signal to the synchronous switch becomes independent of the input voltage and the drive losses can thereby be minimized.
• - Fig. 1 is a circuit diagram of a continuous mode DC-DC converter .
• Figs. 2a - 2c are timing diagrams.
• a DC-DC converter is shown.
• the power converter comprises, on the primary side, a primary winding 101 and a switch 103.
• the primary winding is supplied with power from a DC voltage source 105.
• the switch can for example be an n-channel MOSFET transistor Ql as shown in the figure.
• the drain terminal of the transistor Ql is connected to a first terminal of the primary winding 101 and the source is connected to the low voltage input terminal of the voltage source 105.
• the switch is controlled by a control device (not shown) connected to the gate of the transistor Ql, and is arranged to switch the transistor Ql on and off at desired times .
• the control device can for example collect control data from the output terminals of the secondary side of the converter.
• the DC-voltage source 105 can in turn be connected to an AC- voltage supply (not shown) via a rectifying circuit.
• the primary side feeds a secondary side with energy via a transformer M2.
• the secondary side comprises a secondary winding 109 having an opposite winding direction than the winding on the primary side.
• a first terminal 111 of the winding 109 is connected to a first terminal 113 of a resistor Rl, the emitter 115 of a PNP transistor Q3 , and to a first terminal 117 of an output capacitor CO .
• the second terminal 119 of the resistor Rl is connected to a first terminal 121 of a resistor R2 , the second terminal 123 of which is connected to the second terminal 125 of the winding 109.
• the base 127 of the transistor Q3 is connected to a point 129 between the second terminal 119 of the resistor Rl and the first terminal 121 of the resistor R2.
• the collector 131 of the transistor Q3 is connected to the collector 133 of a NPN transistor Q4.
• the base 135 of the transistor Q4 is in a preferred embodiment connected to the second terminal 125 of the winding 109 via a resistor R3 and a capacitor Cl connected in series.
• the emitter 137 of the transistor Q4 is connected to the second terminal 139 of the capacitor CO and to the source 141 of a FET transistor Q2.
• the gate 143 of the transistor Q2 is connected to a point 145 between the collector terminals of the transistors Q3 and Q4.
• the drain of the transistor Q2 is connected to the second terminal 125 of the winding 109.
• a load ZL can be connected between the terminals of the output capacitor CO.
• Fig. 2b the voltage appearing between the terminals of the secondary winding of the transformer M2 at the corresponding time is shown.
• Fig. 2c the voltage appearing between the gate and source terminals of the transistor Q2 at the corresponding time is shown.
• the pulse generating circuit arrangement generates a drive signal to the synchronous switch which is independent of the input voltage and the drive losses can thereby be minimized.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Dc-Dc Converters (AREA)
• Rectifiers (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=20413780

Family Applications (1)

Country Status (10)

Families Citing this family (4)

Family Cites Families (4)

• 1998
  • 1998-12-21 SE SE9804454A patent/SE517220C2/sv not_active IP Right Cessation
• 1999
  • 1999-10-01 TW TW088116943A patent/TW456096B/zh not_active IP Right Cessation
  • 1999-12-16 CA CA002356187A patent/CA2356187A1/en not_active Abandoned
  • 1999-12-16 WO PCT/SE1999/002390 patent/WO2000038305A1/en not_active Application Discontinuation
  • 1999-12-16 JP JP2000590281A patent/JP2002534049A/ja not_active Withdrawn
  • 1999-12-16 KR KR1020017007808A patent/KR20010093856A/ko not_active Application Discontinuation
  • 1999-12-16 AU AU30920/00A patent/AU3092000A/en not_active Abandoned
  • 1999-12-16 CN CNB99814777XA patent/CN1135682C/zh not_active Expired - Fee Related
  • 1999-12-16 EP EP99964889A patent/EP1145415A1/en not_active Withdrawn
• 2002
  • 2002-07-11 HK HK02105160.1A patent/HK1043447B/zh not_active IP Right Cessation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events