Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N5/00—Details of television systems
  • H04N5/63—Generation or supply of power specially adapted for television receivers
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
  • H02J9/005—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting using a power saving mode
• • 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
  • H02M3/285—Single converters with a plurality of output stages connected in parallel
• • 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
  • H02M1/00—Details of apparatus for conversion
  • H02M1/0003—Details of control, feedback or regulation circuits
  • H02M1/0032—Control circuits allowing low power mode operation, e.g. in standby mode
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
  • Y02B70/10—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

Definitions

• This invention relates generally to the field of power supplies, and, in particular, to standby mode power supplies for television receivers.
• a primary winding of a standby transformer is coupled to the AC mains.
• a transformed voltage across a secondary winding of the standby transformer is full-wave rectified and is regulated by some form of linear regulation to provide power for the video display apparatus in a standby mode of operation.
• This standby power supply consumes power as long as the video display apparatus is connected to the AC mains, an d thus also consumes power during the run mode of operation.
• a main, or run mode, power supply may have a control circuit which is responsive to a decoded on/off signal to energize the run mode power supply during the run mode of operation an d to de-energize the run mode power supply during the standby mode of operation.
• a typical switched mode power supply control IC normally has a start-up resistor connected to its supply voltage pin. The other terminal of the start-up resistor may be coupled either to the AC mains voltage or to a rectified mains voltage.
• the control IC needs to draw a current through the start-up resistor until an internal reference voltage is established within th e control IC. Disadvantageously, however, the control IC continues to draw current through the start-up resistor even after the internal reference voltage within the control IC has been established.
• the present invention is directed to a power supply circuit that reduces the standby consumption attributable to the start-up resistor of a switched mode power supply controller circuit.
• a power supply circuit for a video display apparatus having run an d standby modes of operation comprising: a power supply controller circuit; a resistor having a first terminal coupled to the power supply controller circuit for enabling operation of the power supply controller circuit; and a standby mode power supply for providing an output voltage for the video display apparatus during a standby mode of operation; th e standby mode power supply comprising a standby transformer having a secondary winding coupled to a second terminal of the resistor.
• FIGURES 1-3 show schematic diagrams of standby power supplies that embody the present invention.
• a standby power supply 10 shown in FIGURE 1 A mains voltage V MAINS is coupled from a primary winding nl of a standby transformer Tl to a secondary winding n2.
• the transformed voltage across the secondary winding n2 is rectified by the bridge rectifier Dl and applied to the input of a voltage regulator 1 , which provides a standby voltage, for example +5 V.
• the mains voltage V MAINS is also rectified by a bridge rectifier
• the run power supply is controlled by the switched mode power supply controller circuit
• the optocoupler 3 rather than a relay, is used to turn off the run power supply during the standby mode of operation.
• the light-emitting diode of the optocoupler 3 conducts a current equal to approximately two milliamps.
• the transistor of the optocoupler thus turns on and couples pin 3 of the switched mode power supply controller circuit 2 to a ground, or reference, potential, thereby turning off the switched mode power supply controller circuit 20 turns off.
• the switched mode power supply controller circuit 2 may comprise, for example, a TDA4605 power supply controller integrated circuit manufactured by Siemens Aktiengesellschaft.
• a first terminal of the start-up resistor Rl is coupled to th e switched mode power supply controller circuit 2.
• the standby transformer Tl advantageously utilizes a secondary winding n 3 for feeding a voltage through the diode D3 to the other terminal of the start-up resistor Rl .
• the secondary winding n3 applies a low voltage to the start-up resistor Rl, thereby reducing the power dissipated in the start-up resistor Rl .
• the power dissipation by the start-up resistor Rl may be as low as 100 mW during standby operation.
• a standby power supply 20 provides power to the microcontroller (not shown) during both standby and ru n modes of operation.
• a free-running oscillator circuit 21 includes the primary winding nl and is used in conjunction with said secondary winding n3 of the standby transformer Tl to further reduce power consumption in the standby mode of operation.
• the free-running oscillator illustrated in FIGURE 2 is a blocking oscillator circuit, which is formed by the standby transformer Tl ; resistors R2 and R3; the capacitors Cl and C2; the diode D4; an d the transistor Ql.
• the blocking oscillator 21 operates in a conventional manner and will not be described further herein.
• the depiction of a blocking oscillator circuit in FIGURE 2 is merely exemplary and does not proscribe the use of other oscillator circuits or topologies in the context of the present invention.
• the blocking oscillator 21 runs with an almost constant frequency that is dependent upon the mains voltage.
• the du ty cycle of the oscillation is also substantially constant, so that the energy transferred to the secondary winding n2 is substantially constant.
• This substantially constant energy transfer has two consequences.
• First, the standby power supply 20 is inherently protected against a short circuit condition on the secondary side of the standby transformer Tl .
• Second, parallel voltage regulation techniques can be used to regulate the voltages provided by the secondary windings of the standby transformer Tl .
• the +5 V output provided by the secondary winding n2 can be regulated by the Zener diode VR1.
• the frequency of operation of the blocking oscillator 21 is equal to approximately 100 kHz.
• the blocking oscillator 21 is advantageously used to transform the relatively low mains frequency, for example 50 o r 60 Hz, to a higher frequency. This transformation permits a decrease in the size of the standby transformer Tl, which, in turn, leads to decrease in the standby power consumption attributable to the standby transformer Tl .
• the voltage across the secondary winding n3 is rectified b y the diode D5 to provide a DC voltage V DC for the start-up resistor R4 and for the voltage divider formed by the resistors R7 and R8.
• the DC voltage V DC is equal to approximately +32 V.
• the DC voltage V DC tracks the magnitude of the rectified mains voltage V REC such that the ratio of the magnitude of the rectified mains voltage V REC to the DC voltage V DC is maintained constant as the ratio of th e number of turns of the primary winding nl to the number of turns of the secondary winding n3.
• the optocoupler 3 couples th e DC voltage V DC to the start-up resistor R4 and to the switched mode power supply controller circuit 2 during the run mode of operation.
• the standby transformer Tl may be constructed using an EF16, N67 core with no air gap.
• the inductance of the primary winding of the standby transformer Tl may be equal to approximately 100 mH.
• Approximately 5 layers of 0.1 mm thickness MYLAR ® bran d polymeric film may be used to provide electrical isolation between the primary winding nl and the secondary windings n2 and n3.
• a standby power supply 30 is implemented using a TOPSwitch ® TOP-210 three-terminal, off-line, pulse width modulator switch 31, the use of which is well-known to those having ordinary skill in the art.
• the capacitor C3 is charged to a voltage V DC by a current flowing through the diodes D6 and D7; the resistor R5; and th e secondary winding n3.
• th e voltage V DC is equal to approximately +32 V.
• the voltage V DC is coupled by the optocoupler 3 to the start-up resistor R6 and to th e switched mode power supply controller circuit 2 during the ru n mode of operation.
• the standby transformer Tl may be constructed using an EF16, N67 core with an air gap equal to approximately 0.1 mm.
• the inductance of the primary winding of the standby transformer Tl may be equal to approximately 6 mH, using approximately 160 turns, in tw o layers, of 0.1 mm diameter CuL wire.
• Approximately one layer of 0.1 mm thickness MYLAR ® brand polymeric film may be used to provide electrical isolation between the two layers of wire to reduce parasitic capacitance.
• the secondary winding n2 may u se 13 turns of 0.315 mm diameter CuL wire, and the secondary winding n3 may use 16 turns of 0.315 mm diameter wire .

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Dc-Dc Converters (AREA)
• Television Receiver Circuits (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10802871

Family Applications (2)

Family Applications After (1)

Country Status (11)

Cited By (1)

Families Citing this family (32)

Citations (2)

Family Cites Families (7)

• 1996
  • 1996-11-13 GB GBGB9623612.0A patent/GB9623612D0/en active Pending
• 1997
  • 1997-11-13 CN CNB971996962A patent/CN1161982C/zh not_active Expired - Lifetime
  • 1997-11-13 WO PCT/IB1997/001430 patent/WO1998021885A1/en not_active Ceased
  • 1997-11-13 JP JP52234298A patent/JP3809499B2/ja not_active Expired - Lifetime
  • 1997-11-13 KR KR10-1999-7004262A patent/KR100496482B1/ko not_active Expired - Lifetime
  • 1997-11-13 AU AU48804/97A patent/AU4880497A/en not_active Abandoned
  • 1997-11-13 EP EP97911395A patent/EP0938812B1/en not_active Expired - Lifetime
  • 1997-11-13 MY MYPI97005440A patent/MY128192A/en unknown
  • 1997-11-13 DE DE19782104T patent/DE19782104T1/de not_active Withdrawn
  • 1997-11-13 DE DE69719060T patent/DE69719060T2/de not_active Expired - Lifetime
  • 1997-11-13 WO PCT/IB1997/001431 patent/WO1998021886A1/en not_active Ceased
  • 1997-11-13 US US09/297,416 patent/US6043994A/en not_active Expired - Lifetime
  • 1997-11-13 CN CNB971996954A patent/CN1202659C/zh not_active Expired - Lifetime
  • 1997-11-13 AU AU48803/97A patent/AU4880397A/en not_active Abandoned
  • 1997-11-13 KR KR10-1999-7004165A patent/KR100497578B1/ko not_active Expired - Lifetime
  • 1997-11-13 US US09/297,415 patent/US6144566A/en not_active Expired - Lifetime
  • 1997-11-13 JP JP52234398A patent/JP3897127B2/ja not_active Expired - Lifetime
  • 1997-12-03 TW TW086118169A patent/TW391138B/zh not_active IP Right Cessation

Patent Citations (2)

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