JP2006050879A - High power factor switching regulator circuit - Google Patents

High power factor switching regulator circuit Download PDF

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Publication number
JP2006050879A
JP2006050879A JP2004245965A JP2004245965A JP2006050879A JP 2006050879 A JP2006050879 A JP 2006050879A JP 2004245965 A JP2004245965 A JP 2004245965A JP 2004245965 A JP2004245965 A JP 2004245965A JP 2006050879 A JP2006050879 A JP 2006050879A
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circuit
voltage
signal
capacitor
semiconductor switch
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JP2004245965A
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Japanese (ja)
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Noboru Abe
昇 安倍
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Noboru Abe
昇 安倍
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Priority to JP2004245965A priority Critical patent/JP2006050879A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an efficient switching regulator circuit with a converter of a single circuit, which has power factor improving function, input/output insulating function, and output voltage stabilizing function. <P>SOLUTION: An AC power source 1 is rectified by a rectifying circuit 2, and an AC power is fed to an insulating transformer 4 by opening/closing of a semiconductor switch 3. A secondary winding voltage of the transformer 4 is rectified into a DC voltage by a rectifying circuit 5, and electric power is supplied to a load 7 by smoothing through a capacitor 6. A voltage of the capacitor 6, which is equal to that of the load 7, is detected by a voltage detecting circuit 12, which is compared with a reference voltage by an error-amplifying circuit 11, and the signal acquired by amplifying error is insulated by a photocoupler and fed to a control circuit 10. Inside the control circuit 10, a mutiplication circuit multiplies the error amplified signal, with the signal of voltage detecting circuit 9. The multiplied signal is compared to that of a current-detecting circuit 8, and the signal acquired by amplifying the error is converted into pulse width signals and transmitted to the semiconductor switch 3. Thus, efficiency is improved from 83% to 87%, while the power factor is improved to 0.95 or higher. Further, since the number of components is decreased, reliability is improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a switching power supply circuit used in an electronic device such as a personal computer, and relates to a high power factor switching power supply circuit such as an AC adapter with improved power factor.
  FIG. 2 shows a block circuit diagram of a conventional high power factor switching power supply. The voltage of the AC power source 13 is converted into a power factor by a rectifier circuit 14, an inductor 15, a semiconductor switch 16, a rectifier circuit 17, a capacitor 18, a current detection circuit 24, a voltage detection circuit 25, a control circuit 26, a voltage detection circuit 27, and an error amplification circuit 28. Configure an improved converter. The control circuit 26 compares the signal of the voltage detection circuit 27 with the reference voltage in the error amplification circuit 28, and calculates the error of the signal of the voltage detection circuit 25 using the error amplified signal by the error amplification circuit 28 (× ) In the circuit, convert it to a current reference signal. The reference signal and the signal of the current detection circuit 24 are compared, a signal obtained by amplifying the error is converted into a pulse width signal, and the semiconductor switch 16 is driven.
The inductor 15, the semiconductor switch 16, the rectifier circuit 17, and the capacitor 18 constitute a boost converter circuit. This boost converter circuit is intended to improve the power factor, keep the average voltage of the capacitor 18 constant, and the input current is controlled to a current waveform proportional to the voltage. Thereby, the power factor can be improved to a value of 0.95 or more.
The voltage of the capacitor 18 is insulated and supplied to the load 23 by a flyback converter circuit including a semiconductor switch 19, a transformer 20, a rectifier circuit 21, and a capacitor 22. The control circuit 29 compares the signal detected by the voltage detection circuit 30 with the same capacitor 22 voltage as the voltage of the load 23 and the reference voltage in the error amplification circuit 31, and pulses the signal obtained by amplifying the error by the error amplification circuit 31. The signal is converted into a width signal, and the semiconductor switch 19 is driven.
Next, FIG. 5 of the conventional circuit diagram is compared with FIG. 2 of the conventional block circuit diagram. The AC power source 57 is the AC power source 13. The thermistor 58 and the diodes 59, 60, 61, 62 constitute the rectifier circuit 14. The inductor 71 is the inductor 15. The semiconductor switch 73 is the semiconductor switch 16. The diode 72 is the rectifier circuit 17. The capacitor 74 is the capacitor 18. The semiconductor switch 76 is the semiconductor switch 19. The transformer 78 is the transformer 20. The diode 81 is the rectifier circuit 21. The capacitor 84 is the capacitor 22. The resistor 67 is the current detection circuit 24.
The resistor 63 and the resistor 64 constitute the voltage detection circuit 25. The resistor 65 and the resistor 66 constitute the voltage detection circuit 27. The error amplifier circuit 68 including the reference voltage is the error amplifier circuit 28. The control circuit 26 is configured by the cache calculation circuit 69 and the control circuit 70. The control circuit 70 includes an error amplification circuit and a pulse width conversion circuit. The load 85 is the load 22. The resistor 82 and the resistor 83 constitute the voltage detection circuit 30. The shunt regulator 80 and the resistor 79 constitute the error amplifier circuit 31. The photocoupler 77 insulates the signal from the error amplification circuit 31 and sends it to the control circuit 29.
FIG. 6 shows a conventional operation explanatory chart. A waveform 86 is the voltage of the AC power source 57. A waveform 87 is a current of the AC power source 57. A waveform 88 is a voltage rectified by the diodes 59, 60, 61 and 62. A waveform 89 is the drain terminal voltage of the semiconductor switch 73. A waveform 90 is a voltage of the capacitor 74. A waveform 91 is a voltage of the transformer 78. A waveform 92 is the voltage of the capacitor 84.
  The operation will be described with reference to FIG. The voltage of the AC power source 57 is full-wave rectified by the diodes 59, 60, 61, 62 via the thermistor 58. The thermistor 58 is provided to limit the inrush current that flows to the capacitor 74 via the inductor 71 and the diode 72 when the AC power supply 57 is turned on. The inductor 71, the semiconductor switch 73, the diode 72, and the capacitor 74 are a step-up DC / DC converter circuit. When the semiconductor switch 73 is closed, a full-wave rectified voltage is applied to the inductor 71. The current flowing through the inductor 71 increases in proportion to time. When the semiconductor switch 73 is opened, a back electromotive force is generated so that the current flowing through the inductor 71 continues to flow. Due to this back electromotive force, the current of the inductor 71 charges the capacitor 74 via the diode 72. By repeatedly opening and closing the semiconductor switch 73, the voltage of the capacitor 74 is boosted to a voltage higher than the voltage that has been full-wave rectified by the diodes 59, 60, 61, and 62.
  The voltage of the capacitor 74 is detected by the resistors 65 and 66, and compared with a reference voltage built in the error amplification circuit 68, and the error amplification signal is sent to the cache calculation circuit 69. The chip calculation circuit 69 sends a signal obtained by calculating the error amplification signal and the power supply voltage signal detected by the resistors 63 and 64 to the control circuit 70. This broken signal is a signal proportional to the power supply voltage signal, and its average value is a signal for controlling the voltage of the capacitor 74 to be constant. The resistor 67 detects the current of the AC power source 57. The current detection signal from the resistor 67 and the above-described chipping are calculated, and the signal is sent to the control circuit 70. In the control circuit 70, the two signals (the current detection signal and the signal calculated by the calculation) are compared, and the error amplification signal is converted into a pulse width signal and sent to the semiconductor switch 73. During the opening and closing time of the semiconductor switch 73, the average voltage of the capacitor 74 is constant, and the current flowing through the AC power source 57 is proportional to the voltage of the AC power source 57. Therefore, the power factor can be a value close to 1.0 of 0.95 or more.
  The primary winding of the transformer 78 is connected to the capacitor 74 via the semiconductor switch 76. When the semiconductor switch 76 is closed, a positive voltage is applied to the transformer 78. Since the secondary winding voltage is blocked by the diode 81, an exciting current that increases in proportion to time flows through the primary winding. When the semiconductor switch 76 is opened, a black counter-electromotive force is generated so that the current flowing in the primary winding of the transformer 78 continues to flow. Apply charging current. By opening and closing the semiconductor switch 76, the voltage of the capacitor 74 is transformed to the voltage of the capacitor 84 to convert electric power. A load 85 is connected to the capacitor 84. The voltage of the capacitor 84 is detected by the resistors 82 and 83, and compared with the internal reference voltage of the shunt regulator 80, the error signal is amplified. This error amplification signal is sent to the control circuit 75 via the resistor 79 and the photocoupler 77. The control circuit 75 converts it into a pulse width signal and sends it to the semiconductor switch 76. Through this series of operations, the voltage of the capacitor 84 is constantly stabilized as the waveform 91.
Conventionally, since the circuit configuration is simple, a capacitor input type rectifier circuit has been adopted for a switching power supply. However, in this capacitor input system, since a current containing a large amount of harmonic current flows, the power factor is about 0.6, and an unnecessary current is caused to flow excessively, causing a burden on the AC power supply. In recent years, there has been an increasing demand for a switching power supply including a power factor correction circuit for the purpose of reducing this useless harmonic current.
On the other hand, the conversion efficiency of the switching power supply is naturally required to be good. When the power factor correction circuit is provided, the power factor is improved to 0.95 or more (approximate 1.0), but the loss of the power factor correction circuit is also added, and the conversion efficiency is about 83%. Therefore, there is a strong demand for improved efficiency without deteriorating the power factor.
The cause of the inefficiency is the power factor correction circuit composed of the rectifier circuit 14, the inductor 15, the semiconductor switch 1, the rectifier circuit 17, and the capacitor 18, the semiconductor switch 19, the transformer 20, the rectifier circuit 21, and the capacitor 22. This is because there is a flyback converter configured and power conversion is performed twice.
  Switching power supplies such as AC adapters are used in electronic devices such as personal computers and liquid crystal televisions. These electronic devices include a backlight inverter that can be tolerated even if the ripple voltage is large, and a digital arithmetic circuit that must not have a large ripple voltage. Examining these actual electronic devices, the power source of the digital arithmetic circuit converts the 16V voltage to 3.3V by DC / DC converter conversion. Since the DC / DC converter has the ability to reduce the low-frequency ripple voltage, a low-frequency ripple voltage of 16V is acceptable even at 1V or higher. In consideration of this point, the present invention provides a high-efficiency switching power supply circuit having a single-circuit converter configuration while having a power factor improvement function, an input output insulation function, and an output voltage stabilization function.
  For example, in the case of a 100V AC power source with a DC adapter of 16V5A80W, the conversion efficiency was 83% in the past, but the present invention can be improved to conversion efficiency = 87%. The power factor was 0.95 or more equivalent to the conventional one. The power consumption at no load was 1.2 W in the past, but the present invention was able to reduce to 0.3 W. Furthermore, the number of parts was reduced by about 30%.
  Capacitor input smoothing is stopped, and the input current is controlled proportionally to the input voltage. By adopting an insulation type such as a flyback converter in the converter circuit that improves the power factor, a single converter is realized.
  FIG. 1 shows a block circuit diagram according to the present invention. The AC power source 1 is rectified by the rectifier circuit 2 and AC power is sent to the transformer 4 by opening and closing the semiconductor switch 3. The transformer 4 is an insulating transformer. The secondary winding voltage of the transformer 4 is rectified to a DC voltage by the rectifier circuit 5, smoothed by the capacitor 6, and supplied to the load 7. The voltage of the capacitor 6 that is the same as the voltage of the load 7 is detected by the voltage detection circuit 12, compared with the reference voltage by the error amplification circuit 11, and the signal amplified by the error is insulated by the photocoupler and sent to the control circuit 10. . Inside the control circuit 10, the error amplification signal and the voltage detection circuit 9 signal are calculated by the cache calculation circuit. The signal obtained by the calculation is compared with the signal from the current detection circuit 8, and a signal obtained by amplifying the error is converted into a pulse width signal and sent to the semiconductor switch 3.
  FIG. 3 shows a circuit diagram of the embodiment of the present invention. The AC power supply 31 is connected to an AC terminal of a full-wave rectifier circuit composed of diodes 33, 34, 35, and 36. The diodes 33, 34, 35, and 36 are connected to a bridge circuit. A connection point between the cathode terminal of the diode 33 and the cathode terminal of the diode 35 is a positive terminal. The positive terminal is connected to the resistor 37 and is connected to the drain terminal of the semiconductor switch 42 via the primary winding of the transformer 44. The connection point between the anode terminal of the diode 34 and the anode terminal of the diode 36 is a negative terminal. The negative terminal is connected to the resistor 38 and is connected to the source terminal of the semiconductor switch 42 via the resistor 39. Both terminals of the resistor 39 are connected to the control circuit 41, respectively. A chip calculation circuit 40 is connected to a connection point between the resistor 37 and the resistor 38. The cache calculation circuit 40 and the control circuit 41 are connected. The emitter and collector of the photocoupler 43 are connected to the cache calculation circuit 40, respectively. The secondary winding of the transformer 44 is connected to the capacitor 50 and the load 51 via the diode 47. The positive terminal of the capacitor 50 is connected to the anode terminal of the photocoupler 43 and the resistor 48. The capacitor 50 is connected to the negative terminal of the resistor 49 and the anode terminal of the shunt regulator 46. The cathode terminal of the shunt regulator 46 is connected to the cathode terminal of the photocoupler 43 via the resistor 45. A resistor 48 and a resistor 49 are connected to the reference terminal of the shunt regulator 46.
  3 of the circuit diagram of the embodiment of the present invention is compared with FIG. 1 of the block circuit diagram according to the present invention. The AC power supply 32 is the AC power supply 1. The diodes 33, 34, 35 and 36 are the rectifier circuit 2. Since an electrolytic capacitor having a large capacity does not exist on the primary side, an inrush current limiting component such as a thermistor is unnecessary. Resistor 37 and resistor 38 are voltage detection circuit 9. The resistor 39 is the current detection circuit 8. The cache calculation circuit 40 and the control circuit 41 are the control circuit 10. The semiconductor switch 42 is the semiconductor switch 3. The transformer 44 is the transformer 4. The resistor 45 and the shunt regulator 46 are the error amplifier circuit 11. Resistor 48 and resistor 49 are voltage detection circuit 12. The diode 47 is the rectifier circuit 5. The capacitor 50 is the capacitor 6. The load 51 is the load 7.
FIG. 4 is a chart for explaining the operation of the present invention. A waveform 52 indicates the voltage of the AC power supply 32. A waveform 53 indicates the current of the AC power supply 32. Waveform 54 represents the voltage after bridge rectification of diodes 33, 34, 35, 36. A waveform 55 represents the voltage of the primary winding of the transformer 44. A waveform 56 indicates the voltage of the capacitor 50.
The operation of FIG. 3 according to the embodiment of the present invention will be described. The voltage of the AC power supply 32 is rectified by a bridge rectifier circuit of diodes 33, 34, 35, and 36. This rectified voltage is switched by the semiconductor switch 42 and applied to the primary winding of the transformer 44. When the semiconductor switch 42 is closed, a positive voltage is applied to the transformer 44. Since the secondary winding voltage is blocked by the diode 47, an exciting current that increases in proportion to time flows through the primary winding.
  When the semiconductor switch 42 is opened, the current that was flowing in the primary winding of the transformer 44 continues to flow, and a black back electromotive force is generated. Apply charging current. The semiconductor switch 42 is repeatedly opened and closed. By controlling the opening time and closing time of the semiconductor switch 42, the average voltage of the capacitor 50 can be stabilized and the current can be made proportional to the voltage of the AC power supply 32. That is, a high power factor with less harmonic current can be achieved. The control method will be described below. The voltage of the capacitor 50 is detected by the resistors 48 and 49. This divided voltage detection voltage is connected to the reference terminal of the shunt regulator 46.
  The shunt regulator 46 compares the internal reference voltage with the reference terminal voltage and outputs a signal obtained by amplifying the error from the cathode terminal. This error amplification signal is sent to the cache calculation circuit 40 via the resistor 45 and the photocoupler 43. The photocoupler 43 is a component in which a light emitting diode and a phototransistor are combined, and the signal is insulated because it transmits light. In the chip calculation circuit 40, the signal obtained by dividing the full-wave rectified voltage of the diodes 33, 34, 35, and 36 by the resistor 37 and the resistor 38 and the error amplification signal are calculated and sent to the control circuit 41. The cache arithmetic circuit 40 converts one input signal into a pulse width signal, and converts the other input signal into a pulse width signal by modulating and synthesizing the other input signal to the pulse width, thereby converting the input signal into a two arithmetic signals. An error amplifier in the control circuit 41 compares the current signal detected by the resistor 39 using the signal from the chip calculation circuit 40 as a reference signal and amplifies the error signal. The error amplification signal inside the control circuit 41 is converted into a pulse width signal, and the semiconductor switch 42 is driven. When the voltage of the capacitor 50 is higher than the set voltage, the photocoupler 43 transmits a signal to be lowered. This signal lowers the average value of the signal synthesized with the signal of the waveform 54 by the cache calculation circuit 40. As a result, the average value of the current of the AC power supply 32 decreases in the form of a waveform 53. By this operation, the average value of the voltage of the capacitor 50 is stabilized constant. For this reason, a low frequency ripple voltage is large compared with the past. This low frequency ripple voltage can be reduced to 5% or less by increasing the capacitance of the capacitor 50.
In FIG. 1, the input voltage waveform is detected by the voltage detection circuit 9 and the current of the AC power supply 1 is proportionally controlled. However, even if the input voltage waveform is not detected, the voltage of the transformer 4 is detected and the semiconductor is detected. There is also a method in which the current of the AC power supply 1 is proportional to the voltage by controlling the opening time of the switch 3. Also, the conversion efficiency can be improved by replacing the diode 47 of FIG. 3 with an FET (field effect transistor) and synchronizing with the opening and closing of the semiconductor switch 42.
If the diodes 33, 34, 35, and 36 in FIG. 3 are replaced with FETs (field effect transistors) and are synchronously opened and closed with the AC power supply 32, the conversion efficiency can be further improved. This embodiment is shown in FIG. Field effect transistors 93, 94, 95 and 96 replace diodes 33, 34, 35 and 36, respectively. The other component is a drive circuit for opening and closing the field effect transistors 93, 94, 95, and 96 synchronously.
  FIG. 3 is a block circuit diagram according to the present invention.   It is a conventional block circuit diagram.   It is a circuit diagram of an embodiment of the present invention.   It is operation | movement explanatory chart of this invention.   It is a conventional circuit diagram.   It is a conventional operation explanatory chart.   It is a rectification circuit diagram of efficiency improvement.
Explanation of symbols
1: AC power supply 2: Rectifier circuit 3: Semiconductor switch 4: Transformer 5: Rectifier circuit 6: Capacitor 7: Load 8: Current detection circuit 9: Voltage detection circuit 10: Control circuit 11: Error amplification circuit 12: Voltage detection circuit 13 : AC power supply 14: Rectifier circuit 15: Inductor 16: Semiconductor switch 17: Rectifier circuit 18: Capacitor 19: Semiconductor switch 20: Transformer 21: Rectifier circuit 22: Capacitor 23: Load 24: Current detection circuit 25: Voltage detection circuit 26: Control circuit 27: Voltage detection circuit 28: Error amplification circuit 29: Control circuit 30: Voltage detection circuit 31: Error amplification circuit 32: AC power supply 33-36: Diode 37-39: Resistor 40: Bit calculation circuit 41: Control circuit 42: Semiconductor switch 43: Photocoupler 44: Transformer 45: Resistor 46: Chantregi Regulator 47: Diode 48, 49: Resistor 50: Capacitor 51: Load 52-56: Waveform 57: AC power supply 58: Thermistor 59-62: Diode 63-67: Resistor 68: Error amplification circuit 69: Cake calculation circuit 70 : Control circuit 71: Inductor 72: Diode 73: Semiconductor switch 74: Capacitor 75: Control circuit 76: Semiconductor switch 77: Photocoupler 78: Transformer 79: Resistor 80: Shunt regulator 81: Diode 82, 83: Resistor 84: Capacitor 85: Load 86 to 92: Waveform 93 to 96: Field effect transistor

Claims (3)

  1. In a power supply circuit that converts AC power into DC voltage, a control circuit including an error amplifier circuit and a pulse width conversion circuit, a rectifier circuit, a semiconductor switch, an insulation transformer, a rectifier circuit, a capacitor, and a load voltage detection circuit And a high power factor switching power supply circuit comprising an input current detection circuit.
  2. 2. The high power factor switching power supply circuit according to claim 1, further comprising an input voltage detection circuit and a chip calculation circuit.
  3. 2. The high power factor switching power supply circuit according to claim 1, wherein the rectifier circuit includes a field effect transistor.
JP2004245965A 2004-07-30 2004-07-30 High power factor switching regulator circuit Pending JP2006050879A (en)

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JP2004245965A JP2006050879A (en) 2004-07-30 2004-07-30 High power factor switching regulator circuit

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JP2006050879A true JP2006050879A (en) 2006-02-16

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JP2004245965A Pending JP2006050879A (en) 2004-07-30 2004-07-30 High power factor switching regulator circuit

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102064720A (en) * 2010-12-01 2011-05-18 南京因泰莱电器股份有限公司 Automatic energy obtaining power supply with online monitoring function

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102064720A (en) * 2010-12-01 2011-05-18 南京因泰莱电器股份有限公司 Automatic energy obtaining power supply with online monitoring function

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