JP2007124879A - Power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device in which electric power efficiency can be enhanced, when an output load is low, for example, a system standby mode. <P>SOLUTION: The power supply device 10 serially connects two or more power supply circuits (non-insulated power supply circuit 11, insulated power supply circuit 12). Each electric power supply circuit (non-insulated power supply circuit 11, insulated power supply circuit 12) has an output voltage set lower than the input voltage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power supply device, and more particularly to a power supply device that can reduce power loss during standby.

  For example, in a system in which a power supply device such as a television receiver or a recording device is mounted, it is general that the power consumption does not become zero even when the main function is stopped in the standby mode. In standby mode, the power supply to the main function is stopped, but the remote controller's receiver is used to wait for the remote controller operation, count the timer until the set time, and display the minimum system status. Small electric power is supplied to microcomputers, segment displays, etc.

As a general power supply device that generates a system operating voltage from an AC power supply, for example, there is a combination of a rectifier circuit and a separately-excited / insulated switching power supply circuit.
In such a power supply device, at the time of design, by appropriately selecting each element constant such as the switching frequency, the transformer turns ratio, and the L value of the inductance element, the load size that maximizes the power efficiency is within a certain range. Can be changed.

  Conventionally, this type of power supply apparatus is designed so that the efficiency of the power supply apparatus is maximized when the load is maximum (when the load power becomes maximum).

  As described above, the conventional power supply device is designed so that the efficiency is maximized at the maximum load. Such a power supply device may be used as a load to supply power to a control circuit that operates in response to a radio wave (for example, infrared) command signal from a remote controller. As is well known, the remote controller has a longer waiting period than the actual operation period. Therefore, the control circuit is also waiting for a long time compared to the operation period. When power is supplied to such a control circuit, if the efficiency is maximized at the maximum load as in the conventional power supply device, power loss during standby increases.

  In addition, in the configuration of the conventional power supply device, simply by optimizing the constants of the circuit elements, for example, a peak of power efficiency occurs at a light load of 10 mW to 100 mW, or the power efficiency is 70% or more at such a light load. It was difficult to do. As the factor, for example, it is conceivable that the relative amount of the switching loss or the loss generated in the transformer with respect to the output power becomes large at light load.

  That is, in the switching element, a relatively large switching loss occurs in the rising and falling periods of the switching pulse. However, when the output load is small, the on-period of the switching element must be shortened. Switching loss that occurs during the fall period occupies a large proportion of the transmitted power.

  Further, it has been found from experience that the transformer has a higher degree of coupling as the turn ratio between the primary side and the secondary side approaches 1: 1 even when the core configuration, the winding structure, and the like are optimized. However, the turn ratio is substantially determined by the voltage ratio between the primary side and the secondary side, the load size for maximum efficiency, the duty ratio of the switching pulse at that time, and the like. In order to prevent the ON period of the switching element from becoming too short at light load, the transformer turns ratio must be increased to about the voltage ratio. Therefore, in the configuration of the conventional power supply device, even if an attempt is made to increase the efficiency at light loads, the transformer turns ratio cannot be reduced. Therefore, the coupling degree of the transformer is lowered and the power efficiency is increased. I can't.

  For these reasons, the configuration of the conventional power supply device has a limit in increasing power efficiency at light loads such as when the system is in a standby mode. In addition, there are limits to increasing power efficiency during light loads such as standby mode due to various factors other than those described above.

  Therefore, a problem to be solved by the present invention is to provide a power supply device that can reduce power loss during standby.

  Other objects of the invention will become apparent as the description proceeds.

According to the present invention, in a power supply device (10; 10A; 10B; 10C; 10D; 10E; 10F) having a configuration in which two or more power supply circuits (11; 11A; 11B, 12; 12A) are connected in series, wherein each of the two or more power supply circuit, an input voltage _(E in; E1) output voltage _than; power supply, characterized in that the lower (E1 _{E out)} is obtained.

The power supply device may include a first power supply circuit (11; 11A; 11B) and a second power supply circuit (12; 12A) that receives the output of the first power supply circuit. In that case, the first power supply circuit may be constituted by a non-isolated power supply circuit (11; 11A; 11B), and the second power supply circuit may be constituted by an insulated power supply circuit (12; 12A). In the isolated power supply circuit (12) using the PWM method, when the output voltage (E _out ) of the isolated power supply circuit is 2.5V to 9V, the input voltage (E1) of the isolated power supply circuit is It is preferable to use it at a voltage within ± 20% around the center of about 12V. In the case where the PWM method is adopted for the insulation type power supply circuit (12), the control method of the switching element controlled by the PWM signal at the time of the standby load is set to 1 on the ratio of the on time to the off time about 1: 3. : It is preferable to select and use in the range of 2 to 1: 4. As an isolation transformer (T1) constituting the insulation type power supply circuit (12), the ratio of the number of primary windings to the number of secondary windings (N1: N2) is about 3: 1 to 6: 1 centering around 4: 1. It is desirable to select a range. Further, in the isolated power supply circuit (12) using the PWM method, when the output voltage (E _out ) of the isolated power supply circuit at no load or standby load takes 2.5V to 9V, the insulation It is preferable to use the input voltage (E1) of the power supply circuit at a voltage within ± 20% around the center of about 12V.

  Further, it is preferable that the insulated power supply circuit (12A) operates in the PFM method at the time of heavy load and medium load, and operates in the PWM method at the time of light load. It is desirable to provide hysteresis at the switching point between the PFM method and the PWM method (FIG. 19). Furthermore, it is preferable to further include means (71, 72, 41A, 42A) for varying the output voltage output from the non-insulated power supply circuit according to the load. An auxiliary power supply circuit (13; 13A; 13B) for supplying power to the non-isolated power supply circuit and a control circuit for the PWM-controlled insulated power supply circuit may be further provided.

  The non-isolated power supply circuit (11B) receives an AC input voltage as the input voltage, and the non-isolated power supply circuit includes a rectifier (D1) that converts the AC input voltage into a rectified voltage. May be included. In this case, control means for controlling to use all of the rectified voltage at rated load, to use about half of the rectified voltage at medium load, and to use only a part of the rectified voltage at light load. It is preferable to have (51, 52, 15, 42B).

  In the power supply device of the present invention, a phase control type power supply circuit (11) may be applied to the first power supply circuit, and an insulating power supply circuit (12) may be applied to the second power supply circuit. Alternatively, the phase control type power supply circuit (11G) may be applied to the first power supply circuit, and the separately excited chopper type power supply circuit (12G) may be applied to the second power supply circuit. Further, a step-down chopper type power supply circuit may be applied to the first power supply circuit, and an insulating power supply circuit may be applied to the second power supply circuit. The insulated second power supply circuit (12) is preferably a separately-excited / insulated power supply circuit using a switching element (FET1) and a transformer (T1).

  In this way, by lowering the input voltage of the second power supply circuit by the first power supply circuit, the ON period of the switching element of the second power supply circuit at the time of light load is made relatively long, so that the switching pulse can be generated even at light load. The duty ratio can be optimized. Further, even if the design is made so that the efficiency is improved at a light load as much as the input voltage is lowered, the transformer turns ratio of the second power supply circuit does not become a very large value, and the coupling degree of the transformer is maintained at a high value. I can do it. Therefore, the power efficiency of the second power supply circuit can be designed to be high at light loads or to have a peak at light loads.

  Further, by applying a phase control type power supply circuit to the first power supply circuit, it is possible to transmit power with high efficiency at a light load, and even if the loss between the first power supply circuit and the second power supply circuit is combined, Compared with a single-stage power supply device, the power efficiency at light load can be greatly increased. There is a problem that the output voltage is not stable due to low-frequency noise or cannot be isolated from the external power supply only with the phase control type power supply circuit. However, as the second power supply circuit, a separately excited switching power supply circuit or an insulating power supply circuit is used. These problems are solved by combining the two.

  Even when a step-down chopper type power supply circuit is applied to the first power supply circuit, the efficiency is slightly lower than when a phase control type power supply circuit is applied, but compared to a conventional one-stage power supply device. Thus, the power efficiency at light load can be increased.

  As a specific example of the circuit elements of the first power supply circuit and the second power supply circuit, a four-layer element is applied to the switching element (SCR, Q1) of the first power supply circuit, and the switching element (FET1) of the second power supply circuit. Preferably, a MOSFET is applied, and a flyback transformer is applied to the transformer (T1) of the second power supply circuit. Here, the four-layer element is, for example, a thyristor, triac, PUT (programmable unijunction transistor), GTO (gate turn-off thyristor), SCS (silicon control switch), Shockley diode, SSS (two-terminal thyristor), or the like. .

  More specifically, the voltage output by the first power supply circuit is considered to be able to improve the efficiency at light load as the voltage is lowered to the vicinity of the output voltage of the second power supply circuit. If the input voltage of 100 V or higher is reduced to 30 V or lower or 20 V or lower, a remarkable effect can be obtained as compared with the case where the voltage of 100 V or higher is directly input to the second power supply circuit. Further, if the output voltage of the second power supply circuit is defined as a reference, a remarkable effect can be obtained in the same manner if the voltage is lowered to 5 times the output voltage or less.

More specifically, the winding ratio of the second power supply circuit is (E1 / E _out ) × 0.5 to (E1 / E) where the voltage ratio between the first voltage and the second voltage is (E1 / E _out ). _out ) × 1.5. In addition, it may be designed such that the ratio of the on time and the off time of the switching element of the second power supply circuit is 1: 2 to 1: 4 at the assumed standby load. By doing in this way, the power efficiency at the time of standby load can be made very high.

  In addition, by switching the control method of the switching element of the second power supply circuit between the PFM method and the PWM method according to the output power, the width of the output power can be widened to a certain extent even for medium loads and high loads. Power efficiency can be maintained. It is preferable to switch to PFM when the output load is small, and to switch to PWM when the output load is large.

  Preferably, a second control IC (IC1) that controls the switching element of the first power supply circuit, a second control circuit that controls the switching element of the second power supply circuit, and a control circuit that controls the switching element are integrated. The second control IC is preferably configured as an IC having a higher withstand voltage structure than the first control IC.

  By integrating control circuits and switching elements in this way, the power supply device can be made compact. Further, in the second power supply circuit, a high voltage may be applied to the switching element due to a flyback transformer, an inductance, and the like. Therefore, it is necessary to increase the breakdown voltage of the switching element, but the first control IC and the second control IC With a separate configuration, only the second control IC needs to have a high breakdown voltage. Moreover, in a general one-stage power supply apparatus, when AC 240 V is input, the switching element must have a withstand voltage of 600 V or more. However, as described above, the input voltage of the second power supply circuit is set in the first power supply circuit. Since it is made low, the withstand voltage of the switching element of the second power supply circuit can be kept low. Therefore, the manufacturing cost can be reduced.

  More preferably, an auxiliary power supply circuit (101) for supplying power to the control circuit of the first power supply circuit and the control circuit of the second power supply circuit may be provided. As a result, the fixed loss consumed by the control circuit can be reduced, and the power efficiency of the power supply device at a light load can be further improved.

  As an auxiliary power supply circuit, one auxiliary power supply circuit supplies power to the control circuit (IC1) of the first power supply circuit, the control circuit (IC2) of the second power supply circuit, and the drive circuit of the switching element of the first power supply circuit. Alternatively, a dedicated auxiliary power circuit (102) may be added for the drive circuit (113). Further, the control circuit (IC2) of the second power supply circuit may be operated by the input voltage of the second power supply circuit. The auxiliary power supply circuit may be configured to supply power by rectifying a voltage obtained by dividing the input voltage by a capacitor.

  With the power supply device as described above, the power efficiency with respect to the output load is maximized in the range from no load to the standby load, or is maximized in the range of ± 10% in the standby mode of the system in which the power supply device is mounted. Or can be configured to be maximized at the time of power saving output such as 20 mW to 100 mW. In addition, it is possible to design the power efficiency to be 70% or more or 80% or more in such a range.

  According to such a power supply device, for example, the system is equipped with a main power supply and a standby power supply, and in standby mode, the main power supply is stopped and only the standby power supply is operated. In the case of a system configuration that reduces the power consumption of the mode, the power supply device of the present invention can be effectively used as a standby power supply.

  The reference numerals in the parentheses are given for ease of understanding, and are merely examples, and of course are not limited thereto.

  In the present invention, in the power supply apparatus configured to connect two or more power supply circuits in series, each of the two or more power supply circuits has an output voltage lower than the input voltage, so that power loss during standby is lost. Can be reduced.

A power supply device 10 according to an embodiment of the present invention will be described with reference to FIG. The illustrated power supply apparatus 10 is an apparatus that converts an input voltage from an AC power supply or a DC power supply 20 into an output voltage.
The illustrated power supply device 10 is a power supply device that can reduce power loss during standby, and includes a first power supply circuit 11 that converts an input voltage into an intermediate voltage (an output voltage of the first power supply circuit 11), and an intermediate voltage. The second power supply circuit 12 converts (input voltage of the second power supply circuit 12) into an output voltage.

  Since power loss during standby can be reduced, the power supply device 10 can supply a stable output voltage to the output side without generating a ripple voltage due to intermittent operation on the output side as in a conventional power supply device. .

  The load supplied with the output voltage from the illustrated power supply apparatus 10 may be, for example, a control circuit that operates in response to a radio wave (eg, infrared) command signal from a remote controller. As is well known, the remote controller has a longer waiting period than the actual operation period. Therefore, the control circuit is also waiting for a long time compared to the operation period.

In the power supply device 10, the intermediate voltage (the output voltage of the first power supply circuit 11) is lower than the input voltage, and the output voltage is lower than the intermediate voltage (the input voltage of the second power supply circuit 12).
In the illustrated power supply device 10, the first power supply circuit 11 is configured from a non-insulated power supply circuit, and the second power supply circuit 12 is configured from an isolated power supply circuit.

  The illustrated non-insulated power supply circuit 11 outputs an intermediate voltage (an output voltage of the non-insulated power supply circuit 11) in which power loss is reduced during a standby load. The insulated power supply circuit 12 is a circuit in which the primary side and the secondary side are insulated, and is composed of, for example, a switching power supply circuit.

  FIG. 2 is a characteristic diagram showing electrical characteristics of the power supply device 10 shown in FIG. In FIG. 2, the horizontal axis indicates output current (load current) I or output power, and the vertical axis indicates output voltage V. In FIG. 2, A indicates no load, B indicates standby load, and C indicates maximum load.

  FIG. 3 is a characteristic diagram showing the efficiency characteristics of the power supply device 10 according to the present invention and the conventional power supply device. In FIG. 3, the horizontal axis represents load power, and the vertical axis represents efficiency. In FIG. 3, η (IV) indicates the efficiency characteristic of the power supply device 10 according to the present invention, and η (CV) indicates the efficiency characteristic of the conventional power supply device.

  As is apparent from FIG. 3, the conventional power supply device is designed so that the efficiency η (CV) of the power supply device is the best when the load power becomes maximum (C at the maximum load). On the other hand, the power supply device 10 according to the present invention is configured such that the power consumption of the power supply device 10 is small during a low power load (standby) B or no load A.

  In other words, in the conventional power supply device, when setting the input voltage of the switching power supply, when selecting the transformer turns ratio and pulse width modulation of the switching power supply circuit, the most efficient η (CV ) Is selected to be high. On the other hand, the power supply device 10 according to the present invention is a device in which a first power supply circuit 11 and a second power supply circuit 12 are connected in two stages in series, and includes a first power supply circuit (non-insulated power supply circuit). ) 11 is configured to reduce power loss with respect to the standby load of the second power supply circuit (insulated power supply circuit) 12. That is, as shown in FIG. 3, the power supply device 10 according to the present invention is configured to have the highest efficiency η (IV) at the time B when small power is supplied (standby). Instead, the power supply device 10 according to the present invention may be configured to have the highest efficiency at the time of no load A. In any case, the power supply device 10 according to the present invention operates so as to reduce the power consumption during the standby load B or the no-load A.

  FIG. 4 is a characteristic diagram showing power loss characteristics of the power supply device 10 according to the present invention and the conventional power supply device. In FIG. 4, the horizontal axis indicates load current / power, and the vertical axis indicates loss power. In FIG. 4, loss (IV) indicates the loss power characteristic of the power supply device 10 according to the present invention, and loss (CV) indicates the loss power characteristic of the conventional power supply device.

  As is apparent from FIG. 4, the conventional power supply cannot reduce power consumption during standby load B. For example, when a conventional power supply device is used to supply power to the control circuit, power loss cannot be reduced. On the other hand, in the power supply device 10 according to the present invention, the power consumption can be reduced during the standby load B. In order to reduce the power loss of the power supply device 10 at the time of low power (at the time of standby load) B, it is only necessary to reduce the loss of components such as a transformer and a switching element constituting the second power supply circuit 12. For this purpose, as the input voltage supplied to the second power supply circuit (switching power supply circuit) 12, the above-described intermediate voltage (the output voltage of the first power supply circuit 11) with a small loss is used as the first power supply circuit 11. You can supply from.

  When data is obtained by selecting the input voltage (intermediate voltage) and output voltage of the second power supply circuit 12 so that the loss is reduced in this way, the graph shown in FIG. 5 is obtained. In FIG. 5, the horizontal axis represents the output voltage, and the vertical axis represents the input voltage (intermediate voltage) magnification of the second power supply circuit 12. It can be seen that the input voltage magnification decreases as the output voltage increases.

  In the present invention, the first power supply circuit and the second power supply circuit are used. However, a configuration in which three or more power supply circuits are connected in series is adopted, and each of the three or more power supply circuits has an input voltage. It is obvious to those skilled in the art that the same effect can be obtained even with a power supply device that lowers the output voltage.

  For example, when an input voltage of 200 V or more is used as in Europe, the first power supply circuit, the second power supply circuit, and the third power supply circuit are connected in series and used during standby. It is also conceivable that the efficiency can be improved. Further, even when the input voltage is 100 V, it is conceivable that the standby efficiency may be improved by using three or more stages. The gist of the present invention is to use a power supply device having a configuration in which two or more power supply circuits are connected in series as a method for reducing power loss during standby (increasing efficiency).

With reference to FIG. 6, the power supply apparatus 10 by the 1st Example of this invention is demonstrated. Power supply 10 shown is a device that converts an AC input voltage _{E in} supplied from the AC power source (not shown) to a DC output voltage _{E out.} An output voltage E _out output from the illustrated power supply apparatus 10 is supplied as a load to a control circuit 30 that operates in response to a command signal of radio waves (for example, infrared rays) supplied from a remote controller (not shown). The

  The power supply device 10 includes a non-insulated power circuit 11 as a first power circuit and an insulated power circuit 12 as a second power circuit.

Non-insulated power supply circuit 11 of the illustrated an AC input voltage E _in full-wave rectifier, a full-wave rectifier D1 for outputting a voltage full-wave rectified, from the phase control circuit described later the full-wave rectified voltage A silicon-controlled rectifier SCR that conducts with a control pulse and passes the conducted current, and a capacitor that accumulates the conducted current and outputs a smoothed voltage as the intermediate voltage E1 (output voltage of the non-insulated power supply circuit 11) C1. The non-insulated power circuit 11 further detects the intermediate voltage E1 (output voltage of the non-insulated power circuit 11) and outputs a voltage detection signal, and in response to the detection signal, the control circuit And a phase control circuit 42 for supplying a pulse to the control terminal of the silicon controlled rectifier SCR. As described above, (the output voltage of the non-insulated power supply circuit 11) intermediate voltage E1 is lower than the input voltage E _in. In any case, the detection circuit 41 and the phase control circuit 42 control the intermediate voltage E1 (the output voltage of the non-insulated power supply circuit 11) to be constant.

The insulated power circuit 12 includes an insulation transformer T1 having a primary winding N1 and a secondary winding N2, a field effect transistor FET1 as a switching element connected to the primary winding N1, and a secondary of the insulation transformer T1. It has a diode D2 that rectifies the AC voltage induced in the winding N2, and a capacitor C2 that smoothes the voltage rectified by the diode D2 and outputs an output voltage _Eout . The intermediate voltage E1 (input voltage of the insulation type power supply circuit 12) is applied to a series circuit of the primary winding N1 of the insulation transformer T1 and the field effect transistor FET1. The isolated converter 12 further detects the output voltage _Eout and the output current (load current) flowing through the resistor R1, and outputs an output detection signal, and the output detection signal is fed back to the primary circuit. A feedback circuit 52 for feedback as a signal and a PWM oscillator 53 for generating a pulse width modulation (PWM) signal for turning on / off the field effect transistor FET1 in response to the feedback signal are provided. As described above, the output voltage _Eout is lower than the intermediate voltage E1 (the input voltage of the isolated power supply circuit 12). In any case, the insulated power supply circuit 12 is controlled so that the output voltage E _out becomes constant by the control means comprising a combination of the detection circuit 51, the feedback circuit 52, and the PWM oscillator 53.

With reference to FIG. 7, a power supply apparatus 10A according to a second embodiment of the present invention will be described. The illustrated power supply apparatus 10A has the same configuration as the power supply apparatus 10 shown in FIG. 6 except that the control method of the control means is specified. Therefore, in FIG. 7, the illustration of the non-insulated power supply circuit 11 is omitted, and only the isolated power supply circuit 12 illustrated in FIG. 6 is illustrated. The control means (the detection circuit 51, the feedback circuit 52, and the PWM oscillator 53) causes the insulation type power supply circuit 12 to have an ON time T _{ON of the} switching element (field effect transistor) FET1 controlled by the PWM signal at the standby load B. The ratio T _ON : T _OFF of the off time T _OFF is controlled so as to be selected and used in the range of 1: 2 to 1: 4, centering on about 1: 3.

Hereinafter, the reason for controlling T _ON : T _OFF to be approximately 1: 3 will be described with reference to FIGS. 8 to 10, (A) shows a PWM signal generated from the PWM oscillator 53, and (B) shows an FET1 current flowing through the field effect transistor FET1 of the primary circuit and a diode D2 of the secondary circuit. D2 current flowing through

FIG. 8 shows waveforms when the PWM signal ratio T _ON : T _OFF is selected to be approximately 1: 3. In this case, the sum of the loss in the field effect transistor FET1 due to the FET1 current and the loss in the diode D2 due to the D2 current is substantially the smallest.

FIG. 9 shows a waveform when the PWM signal _ON time T _ON is selected to be longer than the PWM signal OFF time T _OFF . In this case, the loss in the diode D2 due to the D2 current increases, but the loss due to the field effect transistor FET1 due to the FET1 current decreases. However, the total loss is greater than the loss when the PWM signal ratio T _ON : T _OFF is selected to be approximately 1: 3.

FIG. 10 shows a waveform when the _OFF time T _OFF of the PWM signal is selected to be longer than three times the _ON time TON. In this case, the loss in the field effect transistor FET1 due to the FET1 current increases, but the loss in the diode D2 due to the D2 current decreases. In this case as well, the total loss is larger than the loss when the PWM signal ratio T _ON : T _{OFF is set} to approximately 1: 3.

FIG. 11 is a characteristic diagram showing a relationship between the ratio T _ON : T _OFF of the PWM signal and the efficiency η of the isolated power supply circuit 12, and is obtained as a result of measurement by the present inventors. In FIG. 11, the horizontal axis represents T _OFF / T _ON and the vertical axis represents the efficiency η of the insulated power supply circuit 12. From FIG. 11, it can be seen that when T _OFF / T _{ON is} substantially equal to 3, the efficiency η of the insulated power supply circuit 12 is maximized. Therefore, if T _OFF / T _ON is in the range of 2 to 4, the efficiency η of the insulated power supply circuit 12 can be maintained high. More preferably, T _OFF / T _ON may be in the range of 2.5 to 3.5. More preferably, T _OFF / T _ON may be in the range of 2.7 to 3.3.

Anyway, the efficiency η of the isolated power supply circuit 12 is kept high by selecting and using the PWM signal ratio T _ON : T _OFF in the range of 1: 2 to 1: 4, centered on about 1: 3. Can do. More preferably, the PWM signal ratio T _ON : T _OFF should be in the range of 1: 2.5 to 1: 3.5 centered around about 1: 3, and more preferably, the PWM signal ratio T _ON : T _OFF may be in the range of 1: 2.7 to 1: 3.3 centered on approximately 1: 3.

  With reference to FIG. 12, a power supply apparatus 10B according to a third embodiment of the present invention will be described. The illustrated power supply apparatus 10B has the same configuration as that of the power supply apparatus 10 shown in FIG. 6 except that the winding ratio of the insulation transformer T1 constituting the insulation type power supply circuit 12 is specified. Therefore, in FIG. 12, the illustration of the non-insulated power supply circuit 11 is omitted, and only the isolated power supply circuit 12 shown in FIG. 6 is shown.

In the illustrated insulation type power supply circuit 12, the ratio of the intermediate voltage E1 (input voltage of the insulation type power supply circuit 12): the output voltage _Eout is selected to be approximately 4: 1. This is because the coupling degree of the insulating transformer T1 is the highest at this time. E1: E _out ≈4: 1 can be achieved by setting the ratio of the number of primary windings to the number of secondary windings N1: N2 of the insulating transformer T1 to be approximately 4: 1. When N1: N2≈4: 1 is selected, the above-described T1: T2≈1: 3 can be achieved.

  FIG. 13 is a characteristic diagram showing the relationship between the ratio of the number of primary windings to the number of secondary windings N1: N2 of the isolation transformer T1 and the efficiency η of the insulated power supply circuit 12, and the results of measurement by the present inventors. It is obtained. In FIG. 13, the horizontal axis represents N1 / N2, and the vertical axis represents the efficiency η of the insulated power supply circuit 12. From FIG. 13, it can be seen that when N1 / N2 is substantially equal to 4, the efficiency η of the isolated power supply circuit 12 is maximized. Therefore, if N1 / N2 is in the range of 3 to 6, the efficiency η of the insulated power supply circuit 12 can be maintained high. Preferably, N1 / N2 may be in the range of 3.3-5. More preferably, N1 / N2 may be in the range of 3.5 to 4.5.

  Therefore, as the insulation transformer T1 constituting the insulation type power supply circuit 12, the ratio of the number of primary windings to the number of secondary windings N1: N2 is selected in the range of 3: 1 to 6: 1 centering around about 4: 1. By using the insulation transformer, the efficiency η of the insulation type power supply circuit 12 can be kept high. More preferably, the ratio of the number of primary windings to the number of secondary windings N1: N2 of the isolation transformer T1 may be in the range of 3.3: 1 to 5: 1 centered around 4: 1, more preferably The ratio of the number of primary windings to the number of secondary windings N1: N2 of the insulating transformer T1 may be in the range of 3.5: 1 to 4.5: 1, centered around 4: 1.

In the isolated power supply circuit 12 used in the power supply devices 10, 10 </ b> A, and 10 </ b> B according to the first to third embodiments of the present invention described above, the output voltage E _out at the time of no load or standby load is 2.5V to 9V. In this case, it is preferable to use the intermediate voltage E1 (input voltage of the insulated power supply circuit 12) as approximately ± 20% around 12V.

Next, the reason will be described with reference to FIG. FIG. 14 is a characteristic diagram showing the relationship between the intermediate voltage E1 (input voltage of the insulated power supply circuit 12) and the efficiency η of the insulated power supply circuit 12 when the output voltage _Eout is used as a parameter. It was obtained as a result of measurement by a person or the like. In FIG. 14, the horizontal axis indicates the intermediate voltage E1 (input voltage of the isolated power supply circuit 12), and the vertical axis indicates the efficiency η of the isolated power supply circuit 12, and the output voltage E at no load or standby load. The characteristics when _out is set to 2.5V, 5V, and 9V are shown.

From FIG. 14, when the output voltage E _out takes 2.5V to 9V at the time of no load or standby load, the insulation type is obtained when the intermediate voltage E1 (input voltage of the insulation type power supply circuit 12) is approximately 12V. It can be seen that the efficiency η of the power supply circuit 12 is maximized. Therefore, if the intermediate voltage E1 (input voltage of the insulated power supply circuit 12) is in the range of ± 20% around the center of approximately 12V, the efficiency η of the insulated power supply circuit 12 can be maintained high. More preferably, the intermediate voltage E1 (input voltage of the insulated power supply circuit 12) may be within a range of ± 10% around the center of about 12V. More preferably, the intermediate voltage E1 (input voltage of the insulated power supply circuit 12) may be within a range of ± 5% about 12V.

From the above, in the isolated power supply circuit 12, when the output voltage _Eout at no load or standby load takes 2.5V to 9V, the intermediate voltage E1 (input voltage of the isolated power supply circuit 12) is substantially reduced. It can be seen that it is preferable to use ± 20% at the center of 12V.

14 is a circuit in which each element constant such as the turn ratio of the insulating transformer T1 is appropriately selected under each condition that the intermediate voltage E1 is 12V and the output voltage _Eout is 2.5V, 5V, and 9V. Each characteristic is shown. Therefore, if the setting value of the intermediate voltage E1 is designed to be 10V, 5V, or the like, a circuit in which the efficiency η peaks near the setting value can be configured. In any case, the intermediate voltage E1, a voltage close to the output voltage _{E out,} or 1V~2V approximately to a voltage higher than the output voltage _{E out,} considered better kept low by low. Thereby, the turn ratio of the insulating transformer T1 can be made closer to 1: 1, the degree of coupling of the insulating transformer T1 can be increased, and the efficiency η during standby load can be further increased. Even if the intermediate voltage E1 is not lowered to the vicinity of the output voltage _Eout , by reducing it to some extent, the efficiency η at the standby load can be increased as compared with the case where the input voltage _EIN is directly inputted.

  With reference to FIG. 15, a power supply apparatus 10C according to a fourth embodiment of the present invention will be described. The illustrated power supply apparatus 10C has the same configuration as that of the power supply apparatus 10 shown in FIG. 6 except that the insulated power supply apparatus is changed as will be described later. Accordingly, in FIG. 15, the non-insulated power supply circuit 11 is not shown, and the reference numeral 12A is assigned to the isolated power supply circuit.

  The illustrated insulated power supply circuit 12A has the same configuration as that of the insulated power supply circuit 12 shown in FIG. 6 except that an oscillator 53A is provided instead of the PWM oscillator 53.

  FIG. 16 shows a waveform of an oscillation signal generated from the oscillator 53A according to the load weight. In FIG. 16, (A) shows the waveform of the oscillation signal when the load is heavy, (B) shows the waveform of the oscillation signal when the load is light, and (C) shows the oscillation signal when the load is very light. Waveform is shown.

Between load is a light load from the heavy load, as shown in FIG. 16 (A) and (B), the oscillator 53A is on-time T _ON is constant, the pulse frequency such as to vary the off time T _OFF A modulation (PFM) oscillation signal is generated. On the other hand, when the load is less than the light load, as shown in FIGS. 16B and 16C, the oscillator 53A makes the pulse period T constant and the on-time _TON variable. A pulse width modulation (PWM) oscillation signal is generated.

  The reason why the oscillation signal generated from the oscillator 53A is switched from the PFM method to the PWM method in accordance with the lightness of the load is that the control frequency of the oscillation signal becomes lower as the load becomes lighter. For this reason, the control frequency of the oscillation signal is detected, and the oscillator 53A switches the oscillation signal between the PFM method and the PWM method. The frequency detection circuit for detecting the control frequency of the oscillation signal can be detected by integrating the pulse voltage of the oscillation signal generated from the oscillator 53A with an integration circuit.

  FIG. 17 shows the configuration of the oscillator 53A. The oscillator 35A includes a drive circuit 61, an integration circuit 62, a detection circuit 63, and a switching circuit 64.

  FIG. 18 is a waveform diagram for explaining the operation of the oscillator 53A shown in FIG. 18A shows the waveform of the pulse voltage output from the drive circuit 61, and FIG. 18B shows the waveform of the integrated voltage output from the integration circuit 63.

  The drive circuit 61 generates a pulse voltage as shown in FIG. The integrating circuit 62 integrates this pulse voltage and outputs an integrated voltage as shown in FIG. The detection circuit 63 detects the control frequency from this integrated voltage. The switching circuit 64 switches the oscillation signal between the PFM method and the PWM method based on the detected control frequency. In any case, the combination of the integration circuit 62 and the detection circuit 63 serves as a frequency detection circuit that detects the control frequency of the oscillation signal.

  As shown in FIG. 19, hysteresis is provided at the switching point between the PWM method and the PFM method. FIG. 19 is a diagram illustrating output voltage characteristics and frequency control characteristics. In FIG. 19, the horizontal axis represents load current / power, and the vertical axis represents output voltage or frequency.

  A power supply device 10D according to a fifth example of the present invention will be described with reference to FIG. The power supply device 10D shown in FIG. 6 is different from the power supply device 10 shown in FIG. 6 except that the non-insulated power supply circuit is changed as will be described later and further includes a detection circuit 71 and a feedback circuit 72. It has the same configuration. Accordingly, reference numeral 11A is assigned to the non-insulated power supply circuit.

  The detection circuit 71 detects an output current (load current) flowing through the resistor R1 of the second power supply circuit 12, and outputs a current detection signal. The feedback circuit 71 feeds this current detection signal back to the first power supply circuit 11A as a current feedback signal.

  The first power supply circuit 11A is the same as the first power supply circuit 11 of FIG. 6 except that the operations of the detection circuit and the phase control circuit are different from those of the detection circuit 41 and the phase control circuit 42 shown in FIG. It has a configuration. Accordingly, reference numerals 41A and 42A are assigned to the detection circuit and the phase control circuit, respectively.

  The detection circuit 41A not only detects the intermediate voltage E1 (the output voltage of the first power supply circuit 11A) that is the voltage across the capacitor C1, but also receives the current feedback signal. The detection circuit 41A supplies the voltage detection signal and the current feedback signal to the phase control circuit 42A. The phase control circuit 42A supplies a control pulse to the control terminal of the silicon control rectifier SCR in response to the voltage detection signal and the current feedback signal.

  According to such a configuration, the intermediate voltage E1 (the output voltage of the first power supply circuit 11A) output from the first power supply circuit 11A can be varied according to the load weight (the magnitude of the load current). . Anyway, the combination of the detection circuit 71, the feedback circuit 72, the detection circuit 41A, and the phase control circuit 42A is based on the intermediate voltage E1 (the output voltage of the first power supply circuit 11A) output from the non-insulated converter 11A according to the load. ) As a means to vary.

  In the example shown in FIG. 20, the detection circuit 71 and the feedback circuit 72 are provided. Instead of providing these, the second power supply circuit 12 is originally provided as shown by a broken line in FIG. The feedback signal output from the feedback circuit 52 may be fed back to the detection circuit 41A of the first power supply circuit 11A.

  FIG. 21 shows an example of output voltage characteristics and intermediate voltage (input voltage of the second power supply circuit 12) characteristics of the power supply device 10D shown in FIG. In FIG. 21, the horizontal axis indicates the load current or power, and the vertical axis indicates the output voltage or intermediate voltage (the input voltage of the second power supply circuit 12). In FIG. 21, the thick solid line indicates the output voltage characteristic, the thin solid line indicates the first example of the intermediate voltage (input voltage of the second power supply circuit 12) characteristic, and the broken line indicates the intermediate voltage (the second power supply circuit 12 of the second power supply circuit 12). A second example of the input voltage characteristic is shown.

  First, a first example of the intermediate voltage (input voltage of the second power supply circuit 12) characteristic will be described. In this case, the phase control circuit 42A generates a control pulse so that the intermediate voltage E1 (the input voltage of the second power supply circuit 12) increases as the load current increases.

  Next, a second example of the intermediate voltage (input voltage of the second power supply circuit 12) characteristic will be described. First, the operation when the load current increases will be described. In this case, the intermediate voltage E1 (the input voltage of the second power supply circuit 12) is gradually increased until the load current increases to the point (B), but in the range where the load current is larger than the point (B), the intermediate voltage E1 is increased. The phase control circuit 42A generates a control pulse so that the voltage E1 (the input voltage of the second power supply circuit 12) is constant.

  The operation when the load current decreases will be described. In this case, the intermediate voltage E1 (the input voltage of the second power supply circuit 12) is kept constant until the load current reaches a point (A) lower than the point (B). The phase control circuit 42A generates a control pulse so as to gradually lower the intermediate voltage E1 (input voltage of the second power supply circuit 12).

  Thus, a difference (hysteresis) is provided between the direction in which the load current increases and the direction in which the load current decreases. By adopting such a control method, it is possible to prevent the oscillation phenomenon from occurring in the changing portions (A) and (B).

  With reference to FIG. 22, a power supply apparatus 10E according to a sixth embodiment of the present invention will be described. The illustrated power supply apparatus 10E has the same configuration as the power supply apparatus 10 shown in FIG. 6 except that the auxiliary power supply circuit 13 is further provided.

  The auxiliary power supply circuit 13 is a circuit for supplying power to the detection circuit 41 and the phase control circuit 42 of the first power supply circuit 11 and the PWM oscillator 53 of the second power supply circuit 12. In other words, the illustrated power supply device 10E supplies power supplied to a circuit (detection circuit 41 and phase control circuit 42) for controlling the silicon control rectifier SCR and a circuit (PWM oscillator 53) for controlling the field effect transistor FET1. The auxiliary power supply circuit 13 which is another power supply circuit is used.

Auxiliary power supply circuit 13 shown receives an AC input voltage E _in, a capacitor C3 and a full-wave rectifier D3, the diode D4 to further rectify the voltage full-wave rectified by the full wave rectifier D3, rectified by the diode D4 And a capacitor C4 for smoothing the voltage.
Of course, the auxiliary power supply circuit 13 is not limited to that shown in FIG.

FIG. 23 is a circuit diagram showing another auxiliary power circuit 13A. Auxiliary power supply circuit 13A shown, except that the capacitor C5 for receiving an AC input voltage E _in is further added has the same configuration as the auxiliary power supply circuit 13 shown in FIG. 22.

  FIG. 24 is a circuit diagram showing still another auxiliary power circuit 13B. The illustrated auxiliary power circuit 13B has the same configuration as the auxiliary power circuit 13A illustrated in FIG. 23 except that two diodes D5 and D6 are used instead of the full-wave rectifier D3.

  With reference to FIG. 25, a power supply apparatus 10F according to a seventh embodiment of the present invention will be described. The illustrated power supply device 10F has the same configuration as that of the power supply device 10E shown in FIG. 22 except that the operation of the first power supply circuit is changed as will be described later and the mask circuit 15 is further provided. Have. Accordingly, reference numeral 11B is assigned to the first power supply circuit.

  The first power supply circuit 11B has the same configuration as that of the first power supply circuit 11 shown in FIG. 22 except that a phase controller 42B is provided instead of the phase control circuit 42.

  The mask circuit 15 detects the magnitude of the feedback signal output from the feedback circuit 52, outputs a detection signal when the feedback signal exceeds a certain value, and masks in response to the detection signal. And a multi-circuit 82 for supplying a signal to the phase controller 42B.

  With reference to FIGS. 26 to 28, the difference in control pulses supplied from the phase controller 42B to the gate of the silicon controlled rectifier SCR according to the load weight will be described. In each of FIGS. 26 to 28, (A) shows the waveform of the full-wave rectified voltage V output from the full-wave rectifier D1. FIG. 26 (B) shows the waveform of the control pulse at the rated load (heavy load), FIG. 27 (B) shows the waveform of the control pulse at the medium load, and FIG. 28 (B) shows the control at the light load. The waveform of a pulse is shown.

  First, with reference to FIG. 26, the control pulse generated from the phase controller 42B at the rated load (at the time of heavy load) will be described. In this case, the mask circuit 15 does not generate a mask signal. Therefore, the phase controller 42B generates a control pulse that uses all of the full-wave rectified voltage output from the full-wave rectifier D1, as shown in FIG.

  Next, with reference to FIG. 27, the control pulse generated from the phase controller 42B at the time of medium load will be described. In this case, the mask circuit 15 generates a mask signal for masking the control pulse once every two times. Therefore, as shown in FIG. 27B, the phase controller 42B generates a control pulse that uses half of the full-wave rectified voltage output from the full-wave rectifier D1. In other words, at the time of medium load, the phase controller 42B generates a control pulse that uses a half-wave rectified voltage.

  Finally, with reference to FIG. 28, the control pulse generated from the phase controller 42B at the time of light load will be described. In this case, the mask circuit 15 generates a mask signal for masking the control pulse at a rate of twice every three times. Therefore, as shown in FIG. 28B, the phase controller 42B uses a part of the full-wave rectified voltage output from the full-wave rectifier D1 (in this example, 1/3). Generate a control pulse.

  Anyway, the combination of the detection circuit 51, the feedback circuit 52, the mask circuit 15 and the phase controller 42B uses all of the full-wave rectified voltage at the rated load, and uses about half of the full-wave rectified voltage at the medium load. However, it functions as a control means for controlling to use only a part of the full-wave rectified voltage at light load.

  In the example shown in FIGS. 26 to 28, the control pulse generated from the phase controller 42B is switched to three stages, but may be switched to two stages. Hereinafter, a case where the control pulse is switched in two stages will be described as an example.

  With reference to FIG. 29, the operation of the detection circuit 81 will be described. FIG. 29 is a diagram showing the characteristics of the feedback signal output from the feedback circuit 52. The horizontal axis represents the load current, and the vertical axis represents the signal current or voltage.

  29 that the signal current (voltage) becomes smaller (lower) as the load current becomes larger. The detection circuit 81 detects that the load current has become smaller than a predetermined value when the signal current (voltage) exceeds a certain value, and outputs a detection signal.

  In response to this detection signal, the multi-circuit 82 outputs a mask signal as will be described later. The multi circuit 82 is composed of, for example, a bistable multivibrator, and outputs a multi output signal as a mask signal.

  FIG. 30 is a block diagram showing the configuration of the phase controller 42B. The phase controller 42B includes a phase control circuit 91, a switch circuit 92, and a drive circuit 93.

  With reference to FIG. 31, the operation of power supply device 10F when the load current is small will be described. 31A shows the waveform of the full-wave rectified voltage output from the full-wave rectifier D1, FIG. 31B shows the waveform of the phase control signal output from the phase control circuit 91, and FIG. Indicates the waveform of the multi-trigger signal generated by the multi-circuit 82, (D) indicates the waveform of the multi-output signal (mask signal) output from the multi-circuit 82, and (E) indicates the output from the drive circuit 93. The waveform of a drive signal is shown.

  The full wave rectifier D1 outputs a voltage subjected to full wave rectification as shown in FIG. The phase control circuit 91 generates a phase control signal as shown in FIG. On the other hand, the multi-circuit 82 is triggered by a multi-trigger signal as shown in FIG. 31 (C) and outputs a multi-output signal (mask signal) as shown in FIG. 31 (D). The switch circuit 92 masks the phase control signal generated from the phase control circuit 91 with the mask signal output from the mask circuit 15 and outputs the masked signal. The masked signal is supplied to the drive circuit 93. In response to the masked signal, the drive circuit 93 outputs a drive signal as shown in FIG. This drive signal is supplied as a control pulse to the control terminal of the silicon controlled rectifier SCR.

  The multi-circuit 82 shown in FIG. 25 is composed of a bistable multivibrator, but it is needless to say that the multi-circuit 82 is not limited to this. For example, the multi-circuit 82 may be composed of a monostable multivibrator.

  With reference to FIG. 32, another multi-circuit 82A will be described. The illustrated multi-circuit 82 </ b> A includes a bistable multivibrator 821, a differentiation circuit 822, and a bistable multivibrator 823.

  FIG. 33 shows a waveform diagram for explaining the operation of the multi-circuit 82A shown in FIG. 33A shows the waveform of the output signal of the bistable multivibrator 821, and FIG. 33B shows the waveform of the output signal of the bistable multivibrator 823.

  In response to the multi-trigger signal (see FIG. 31C), the bistable multivibrator 821 outputs a first multi-signal as shown in FIG. The multi-signal is differentiated by the differentiation circuit 822, and the differentiation signal is output from the differentiation circuit 822. In response to this differential signal, the bistable multivibrator 823 outputs a second multi-signal as shown in FIG. This second multi-signal is supplied as a mask signal to the switch circuit 92 of the phase controller 82B.

  As is clear from FIG. 33, the output signal of the bistable multivibrator 823 has a waveform that is substantially obtained by dividing the output signal of the bistable multivibrator 821 by two.

  Still another multi-circuit 82B will be described with reference to FIG. The illustrated multi-circuit 82B has the same configuration as the multi-circuit 82A shown in FIG. 32 except that a monostable multivibrator 824 is provided instead of the bi-stable multivibrator 823.

  FIG. 35 shows the waveform of the output signal of the monostable multivibrator 824. The output signal of the monostable multivibrator 824 is supplied as a mask signal to the switch circuit 92 of the phase controller 82B.

  Since there are various known methods for using a part of these full-wave rectified voltages, it is obvious that those skilled in the art can easily replace them with various methods.

Next, a supplementary description of the above embodiment will be given with reference to FIGS.
First, an operation other than the standby load will be described with reference to FIG. FIG. 36 is a diagram illustrating operation waveforms at the standby load and the rated load in the insulated power supply circuit (second power supply circuit) 12 of the second embodiment.

  In the figure, (A-1) and (B-1) show waveforms of the input pulse of the switching element FET1 during standby load and the current flowing through the insulating transformer (flyback transformer) T1. Further, (A-2) and (B-2) show respective waveforms when the rated load is larger than the standby load.

  36 (A-1) and (B-1) are the same as the waveforms in FIG. At the time of circuit design, the duty ratio of the switching pulse at the time of standby load can be designed in the vicinity of 1/3 by appropriately selecting the turn ratio and switching frequency of the isolation transformer T1. With such a design, the total switching loss during standby load is reduced, and the efficiency η during standby load is improved.

As shown in FIGS. 36A-2 and B-2, as the output load increases in the same power supply circuit, the duty ratio of the input pulse of the switching element FET1 is gradually increased by the control circuit. Thus, the energy stored in on-time T _ON in the isolation transformer T1 increases. In addition, since the amount of current released on the secondary side of the insulating transformer T1 during the OFF time _TOFF of the switching element FET1 increases, it is possible to cope with a large load.

Next, with reference to FIG. 37, a selection example of the turn ratio of the insulating transformer will be described. FIG. 37 shows the number of turns of the insulation transformer in each of the power supply circuit in which the voltage ratio between the intermediate voltage E1 (input voltage of the insulated power supply circuit 12) and the output voltage _Eout is “2” and the power supply circuit in which the voltage ratio is “5”. It is a characteristic view which shows the relationship between ratio and efficiency (eta) of the insulation type power supply circuit 12, respectively.

It turns ratio of the isolation transformer T1 (N1 / N2) is an intermediate voltage E1 input Isolated power supply circuit (second power supply circuit) 12, by the set value of the output voltage E _out output from the circuit 12 The selected value will be different. The specific selection method is as follows. First, the voltage ratio between the intermediate voltage E1 output voltage E _out, as the same value turns ratio of the isolation transformer T1, L values of the isolation transformer T1, the switching frequency, such as the duty ratio of the switching pulses during standby load, other Select circuit constants. Next, for the insulated power supply circuit 12 configured by selecting circuit constants in this way, the turn ratio of the insulation transformer T1 is optimized in consideration of the influence of various specific parameters not taken into consideration at the design stage. That is, the efficiency η of the insulated power supply circuit 12 is measured while changing the turn ratio of the insulation transformer T1 as a parameter, and the turn ratio at which the efficiency η is maximized is obtained.

FIG. 37 shows the relationship between the turn ratio of the insulation transformer T1 and the efficiency η of the insulation type power supply circuit 12 at this time. As shown in FIG. 37, the efficiency η peaks when the turn ratio (N1 / N2) of the insulating transformer T1 is close to the voltage ratio (E1 / E _out ) of the input and output. Accordingly, the turn ratio of the insulating transformer T1 is set to a range of (E1 / E _out ) × 0.5 to (E1 / E _out ) × 1.5, and more preferably (E1 / E _out ) × 0.65- ( The efficiency η of the insulated power supply circuit 12 can be increased by setting the range of E1 / E _out ) × 1.35.

  Next, a second example of switching between PWM control and PFM control according to the load weight will be described with reference to FIG. FIG. 38 is a waveform diagram showing an oscillation signal generated from the oscillator in accordance with the load weight in the second switching example. FIG. 38A shows the waveform of the oscillation signal when the load is heavy, and FIG. The waveform of the oscillation signal when the load is light is shown, and (C) shows the waveform of the oscillation signal when the load is very light.

  As described with reference to FIG. 16, the control of the switching element FET1 of the second power supply circuit (for example, the isolated power supply circuit 12) is PFM control when the load is small, and PWM control when the load is large. It is avoided that the on-time of switching becomes very small when the load is applied, and as a result, it is possible to cope with a wide output load.

  Similarly, as shown in FIG. 38, by switching to PWM control when the load is small and switching to PFM control when the load is large, it is possible to cope with a wide output load as a result.

Because switching losses are relatively large in rising period and a falling period of the switching pulse, the ON time T _ON of the switching element FET1 is becomes shorter, the proportion occupied by the rising occupying the ON time T _ON and fall times Increase. This means that the ratio of loss to the transmitted power increases. Therefore, as shown in FIG. 38, by the on-time T _ON is extending the switching period T is switched to the PFM control After some extent shorter, it is possible to correspond to a small output load without increasing the loss.

  Hereinafter, variations of the power supply device of the present invention will be described with reference to FIGS.

FIG. 39 shows a power supply apparatus 10G of the eighth embodiment, and is an example in which both the first power supply circuit 11G and the second power supply circuit 12G are non-insulated.
The power supply apparatus 10G of the eighth embodiment is composed of a phase control type first power supply circuit 11G and a separately excited chopper type / step-down type second power supply circuit 12G.

The first power supply circuit 11G, for example by entering the switching element Q1 is turned on and off based on the input voltage _{E IN} of AC100V or AC200V the phase of the AC voltage, for example, lower than the input voltage _{E IN} intermediate voltage E1 Is generated. In the phase control method, the switching element Q1 is driven at a phase where the AC voltage becomes small at light load, so that the power efficiency for light load can be very high.

  In such a phase control type power supply circuit, as shown in FIG. 6, a full-wave rectifier circuit or a half-wave rectifier circuit may be provided before the switching element (silicon-controlled rectifier SCR). However, not providing a rectifier circuit as shown in FIG. 39 is effective in that the loss in the rectifier circuit can be eliminated and the power supply apparatus can be made compact.

The second power supply circuit 12G is a switching power supply circuit of the separately excited chopper mode, step-down, to produce an output voltage E _OUT which enter the intermediate voltage E1 steps down it. The configuration shown is a configuration of a general step-down DC / DC converter, where FET2 is a switching element such as a MOSFET, 54 is a control circuit that performs switching control, D7 is a rectifier diode such as a Schottky barrier diode, L is a reactor, 55 is a detection circuit for the output voltage E _OUT , and C2 is a smoothing diode.

According to such a power supply apparatus 10G, the intermediate voltage E1 is supplied is lower than the input voltage E _IN to the second power supply circuit 12G, as compared with the case where the input voltage E _IN is directly input, output load Even when it is small, the ON time of the switching element FET2 can be lengthened. Thereby, the power efficiency at the time of light load can be made high.

FIG. 40 shows a power supply device 10H of the ninth embodiment, in which the first power supply circuit 11H is a non-insulating type, and an insulating power supply circuit 12Ha and a non-insulating power supply circuit 12Hb are provided at the subsequent stage. It is provided in parallel.
Such power supply 10H includes a voltage _{E OUT1} which is insulated, is useful in a system for the power supply and not requiring voltage _{E OUT2} insulation.

  Here, as the non-insulated first power supply circuit 11H, it is preferable to apply a phase control type power supply circuit as shown in FIG. 6 or FIG. As the subsequent-stage insulated power supply circuit 12Ha, a flyback power supply circuit shown in FIG. 6 or a forward power supply circuit may be applied. Further, as the subsequent non-insulated power supply circuit 12Hb, a separately excited switching power supply circuit is preferably applied, and a step-down or step-up / step-down switching power supply circuit can be applied.

  FIG. 41 shows a power supply device 10I of the tenth embodiment.

In the figure, _EIN is an AC input voltage, Q1 is a switching element of the first power supply circuit, L2 is a choke coil for surge removal, C1 is a smoothing capacitor, R14 and R15 are detection resistors for intermediate voltage E1, and IC1 is a first resistor. the control circuit of power source circuit, 101 first auxiliary power supply circuit for supplying power for the control circuit, 111 is a filter circuit for generating a synchronizing signal of the input voltage E _iN for phase control.

Further, T1 is a flyback isolation transformer of the second power supply circuit, D16 are rectifying diodes, C2 smoothing capacitor, L1, C21 choke coil and a capacitor for ripple removal, R19, R20 detection of the output voltage _{E OUT} A resistor, 121 is a feedback circuit using a photocoupler, and IC2 is a control circuit for the second power supply circuit.

  The switching element Q1 is composed of, for example, a thyristor or other four-layer element, and the signal of the control circuit IC1 is input to its control terminal via the differentiation circuit 112 or the diode D15, and the switching element Q1 is turned on / off.

  The control circuit IC1 is obtained by integrating a circuit that controls the switching element Q1 by a phase control method, for example, on one semiconductor chip. Then, the detection voltages from the detection resistors R4 and R5 and the synchronization signal from the filter circuit 111 are input, and a drive signal is output to the switching element Q1 based on these signals so that the detection voltage is maintained at a constant value. . The control circuit IC is formed by a general breakdown voltage process.

  The feedback circuit 121 causes a current proportional to the detection voltage from the detection resistors R19 and R20 to flow to the light emitting diode IC4-2 of the photocoupler by the variable shunt regulator device IC3, and this light emission is supplied to the phototransistor IC4-1 of the photocoupler. And outputs the detected voltage to the control circuit IC2.

  The control circuit IC2 is obtained by integrating a switching element (for example, a MOSFET) of a second power supply circuit, an oscillator for switching control, and a control circuit for performing switching control on, for example, one semiconductor chip. Then, based on the detection voltage from the photocoupler, the internal switching element is turned on / off by PWM control or PFM control so that the detection voltage is maintained at a constant value, and the primary winding of the isolation transformer T1 is intermittently provided. Thus, an intermediate voltage E1 is applied to pass a current.

  Since a large electromotive force may be input from the isolation transformer T1 to the built-in switching element, the control circuit IC2 is formed by a high breakdown voltage process and has a high breakdown voltage structure.

The first auxiliary power supply circuit 101, the input voltage _{E IN} and generates an operating voltage of the control circuit IC1, IC2 takes in the voltage divided by the capacitor C11. This operating voltage is regulated by the Zener diode D12, then rectified by the diode 14, and smoothed and output by the capacitor C15.

  In this way, by supplying power from the first auxiliary power supply circuit 101 to the control circuits IC1 and IC2, the fixed loss consumed in the control system can be reduced, and the power efficiency at light load can be further improved. .

  FIG. 42 shows a power supply device 10J of the eleventh embodiment. The power supply device 10J is obtained by adding a drive circuit 113 and a second auxiliary power supply circuit 102 to the power supply device 10I of FIG.

  The drive circuit 113 converts the control signal from the control circuit IC1 into the drive voltage of the switching element Q1 by the two-stage transistors Q2 and Q3, and outputs it to the control terminal of the switching element Q1.

The second auxiliary power supply circuit 102 takes in a voltage obtained by dividing the input voltage _EIN by the capacitor C12 and supplies it to the drive circuit 113. The supply voltage is regulated by the Zener diode D11, then rectified by the diode D13, and smoothed and output by the capacitor C24.

  As described above, the second auxiliary power supply circuit 102 is provided independently of the first auxiliary power supply circuit 101, and the drive circuit 113 is supplied with the operating voltage, so that the control circuit IC1 and the drive circuit 113 have optimum power respectively. Supply is performed, and the power efficiency can be further improved.

FIG. 43 shows a power supply device 10K of the twelfth embodiment.
The power supply device 10K has substantially the same configuration as the power supply device 10I of FIG. 41, and does not supply the operating voltage of the second control circuit IC2 from the first auxiliary power supply circuit 101, but the output voltage of the first power supply circuit. The difference is that (intermediate voltage E1) is supplied as the operating voltage.

  Since the intermediate voltage E1 is set to a low voltage by the first power supply circuit, it may be an appropriate voltage as the operating voltage of the control circuit IC2. In such a case, the intermediate voltage E1 can be supplied as the operating voltage of the control circuit IC2 as in the power supply device 10K of FIG.

  Since the second control circuit IC2 may be applied with a high voltage from the isolation transformer T1 to the built-in switching element as described above, the power supply device 10K includes the first control circuit IC1 and the second control circuit IC2. This is useful in that the power supply line from the control circuit IC2 can be separated.

FIG. 44 shows a power supply device 10L of the thirteenth embodiment.
The power supply device 10L has substantially the same configuration as the power supply device 10J of FIG. 42, and does not supply the operating voltage of the second control circuit IC2 from the first auxiliary power supply circuit 101, but the output voltage of the first power supply circuit. The difference is that (intermediate voltage E1) is supplied as the operating voltage.

  Since there is a possibility that a high voltage may be applied from the isolation transformer T1 to the built-in switching element in the second control circuit IC2, the power supply lines of the first control circuit IC1 and the second control circuit IC2 can be separated. In this respect, the power supply device 10L is useful.

  Although the present invention has been described with reference to preferred embodiments, it is obvious that various modifications can be made by those skilled in the art without departing from the spirit of the present invention.

It is a block diagram which shows the power supply device which concerns on embodiment of this invention. It is a characteristic view which shows the electrical property of the power supply device shown in FIG. It is a characteristic view which shows the efficiency characteristic of the power supply device by this invention, and the conventional power supply device. It is a characteristic view which shows the power loss characteristic of the power supply device by this invention, and the conventional power supply device. It is a figure which shows the input voltage magnification of a 2nd power supply circuit. It is a block diagram which shows the power supply device by 1st Example of this invention. It is a block diagram which shows the power supply device by 2nd Example of this invention. It is a figure which shows a waveform when the ratio of the on time of PWM signal: off time is selected to about 1: 3. It is a figure which shows a waveform at the time of selecting the ON time of a PWM signal longer than the OFF time of a PWM signal. It is a figure which shows the waveform at the time of selecting the OFF time of a PWM signal longer than 3 times of ON time. It is a characteristic view which shows the relationship between ratio _TON : _{TOFF of a} PWM signal, and the efficiency of an insulation type power supply circuit. It is a block diagram which shows the power supply device by 3rd Example of this invention. It is a characteristic figure which shows the relationship between the number of primary windings of an isolation transformer to the number of secondary windings N1: N2 and the efficiency of an insulation type power supply circuit. It is a characteristic view which shows the relationship between the intermediate voltage (input voltage of an insulation type power supply circuit) when an output voltage is used as a parameter, and the efficiency of an insulation type power supply circuit. It is a block diagram which shows the power supply device by the 4th Example of this invention. It is a figure which shows the waveform of the oscillation signal generate | occur | produced from an oscillator according to the lightness of load. It is a block diagram which shows the structure of the oscillator used for the insulation type power supply circuit of the power supply device shown in FIG. FIG. 18 is a waveform diagram for explaining the operation of the oscillator shown in FIG. 17. It is a characteristic figure which shows a mode that the hysteresis was provided in the switching point of a PWM system and a PFM system. It is a block diagram which shows the power supply device by the 5th Example of this invention. It is a figure which shows the example of the output voltage characteristic and intermediate voltage (input voltage of an insulation type power supply circuit) characteristic of the power supply device shown in FIG. It is a block diagram which shows the power supply device by the 6th Example of this invention. FIG. 23 is a circuit diagram showing another auxiliary power supply circuit used in the power supply device shown in FIG. 22. FIG. 23 is a circuit diagram showing still another auxiliary power supply circuit used in the power supply device shown in FIG. 22. It is a block diagram which shows the power supply device by the 7th Example of this invention. It is a wave form chart for explaining a control pulse generated from a phase controller at the time of rated load (at the time of heavy load). It is a wave form diagram for demonstrating the control pulse generate | occur | produced from a phase controller at the time of medium load. It is a wave form diagram for demonstrating the control pulse generate | occur | produced from a phase controller at the time of light load. It is a figure which shows the characteristic of the feedback signal which a feedback circuit outputs for demonstrating operation | movement of the detection circuit in the mask circuit used for the power supply device shown in FIG. It is a block diagram which shows the structure of the phase controller used for the power supply device shown in FIG. FIG. 26 is a waveform diagram for explaining the operation of the power supply device shown in FIG. 25 when the load current is small. FIG. 26 is a block diagram showing a configuration of another multi-circuit used in the power supply device shown in FIG. 25. FIG. 33 is a waveform diagram for explaining the operation of the multi-circuit shown in FIG. 32. FIG. 26 is a block diagram showing a configuration of still another multi-circuit used in the power supply device shown in FIG. 25. It is a wave form diagram which shows the waveform of the output signal of the 1 stable multivibrator in FIG. It is a figure which shows the operation | movement waveform at the time of the standby load and rated load in the power supply device of a 2nd Example. FIG. 6 is a characteristic diagram showing a relationship between a turn ratio of an insulating transformer and efficiency η of an insulated power supply circuit in two power supply circuits having different voltage ratios between an input voltage and an output voltage. It is a figure which shows the 2nd example of the waveform of the oscillation signal generate | occur | produced from an oscillator according to the lightness of load. It is a figure which shows the power supply device of the 8th Example of this invention. It is a block diagram which shows the power supply device of the 9th Example of this invention. It is a circuit diagram which shows the power supply device of the 10th Example of this invention. It is a circuit diagram which shows the power supply device of the 11th Example of this invention. It is a circuit diagram which shows the power supply device of the 12th Example of this invention. It is a circuit diagram which shows the power supply device of the 13th Example of this invention.

Explanation of symbols

10, 10A to 10L Power supply device 11, 11A, 11B, 11G, 11H First power supply circuit (non-insulated power supply circuit)
12, 12A, 12G, 12Ha, 12Hb Second power supply circuit 13, 13A, 13B, 101, 102 Auxiliary power supply circuit 15 Mask circuit 20 AC power supply or DC power supply 30 Load (control circuit)
E _in input voltage E1 intermediate voltage E _out output voltage 41, 41A detection circuit 42, 42A phase control circuit 42B phase controller 51 detection circuit 52 feedback circuit 53 PWM oscillator 53A oscillator 61 drive circuit 62 integration circuit 63 detection circuit 64 switching circuit 71 Detection circuit 72 Feedback circuit 81 Detection circuit 82 Multi-circuit 821 Bistable multivibrator 822 Differentiation circuit 823 Bistable multivibrator 824 1-stable multivibrator 91 Phase control circuit 92 Switch circuit 93 Drive circuit 111 Filter circuit 113 Drive circuit 121 Feedback circuit D1 All Wave rectifier SCR Silicon controlled rectifier C1 Capacitor T1 Isolation transformer N1 Primary winding N2 Secondary winding FET1 Field effect transistor (switching element)
D2 Diode C2 Capacitor C3 Capacitor D3 Full-wave Rectifier D4 Diode C4 Capacitor C5 Capacitor D5, D6 Diode Q1 Switching element (four-layer element) of the first power supply circuit
IC1 Control circuit of first power supply circuit (first control IC)
IC2 Control circuit for second power supply circuit (second control IC)

Claims (48)

  A power supply apparatus having a configuration in which two or more power supply circuits are connected in series, wherein each of the two or more power supply circuits has an output voltage lower than an input voltage. The power supply device includes a first power supply circuit and a second power supply circuit that receives the output of the first power supply circuit as an input,
The first power circuit is a non-insulated power circuit;
The power supply device according to claim 1, wherein the second power supply circuit includes an insulated power supply circuit. The power supply device includes a first power supply circuit and a second power supply circuit that receives the output of the first power supply circuit as an input,
The first power circuit is a non-insulated power circuit;
The power supply device according to claim 1, wherein the second power supply circuit includes a non-insulated power supply circuit. The power supply device includes a first power supply circuit and a second power supply circuit that receives the output of the first power supply circuit as an input,
The first power circuit is a non-insulated power circuit;
The second power supply circuit comprises a power supply circuit in which a non-isolated power supply circuit that inputs the output of the first power supply circuit and an isolated power supply circuit that inputs the output of the first power supply circuit are arranged in parallel. The power supply device according to claim 1, wherein the power supply device is provided.   In the insulation type power supply circuit using the PWM method, when the output voltage of the insulation type power supply circuit is 2.5V to 9V, the input voltage of the insulation type power supply circuit is used at a voltage of 12V ± 20%. The power supply device according to claim 2 or 4, wherein   In the case where the PWM method is adopted for the insulated power supply circuit, the ratio between the on time and the off time of the switching element controlled by the PWM signal is set to 1: 2 to 1: 4 at the standby load. The power supply device according to claim 5.   6. The power supply according to claim 5, wherein an insulating transformer having a ratio of the number of primary windings to the number of secondary windings of 3: 1 to 6: 1 is used as an insulating transformer constituting the insulating power supply circuit. apparatus.   In the isolated power supply circuit using the PWM method, when the output voltage of the isolated power supply circuit takes 2.5V to 9V at no load or standby load, the input voltage of the isolated power supply circuit is set to 12V ± The power supply device according to claim 2 or 4, wherein the power supply device is used at a voltage of 20%.   6. The power supply apparatus according to claim 5, wherein the insulated power supply circuit operates in a PFM method at a heavy load and a medium load, and operates in a PWM method at a light load.   The power supply device according to claim 9, wherein hysteresis is provided at a switching point between the PFM method and the PWM method.   The power supply apparatus according to any one of claims 5 to 7, further comprising means for varying an output voltage output from the non-insulated power supply circuit in accordance with a load.   The power supply apparatus according to any one of claims 2 to 10, further comprising means for varying an output voltage output from the first power supply circuit in accordance with a load.   The auxiliary power supply circuit for supplying electric power to the non-isolated power supply circuit and the control circuit of the isolated power supply circuit that is PWM-controlled, further comprising: The power supply described. The first power supply circuit and the second power supply circuit are provided with a switching element that intermittently takes an input voltage by a switching operation, and a control circuit that controls the switching element,
The auxiliary power supply circuit for supplying electric power to the control circuit of the first power supply circuit and the control circuit of the second power supply circuit is further provided. The power supply described. The non-isolated power supply circuit receives an AC input voltage as the input voltage, and the non-isolated power supply circuit includes a rectifier that converts the AC input voltage into a rectified voltage,
Control means for controlling to use all of the rectified voltage at rated load, use about half of the rectified voltage at medium load, and use only part of the rectified voltage at light load. The power supply device according to any one of claims 5 to 7 and 13, wherein: A first power supply circuit that generates a first voltage lower than a peak voltage of the input voltage from an AC input voltage;
A second power supply circuit that generates and outputs a second voltage from the first voltage,
The first power supply circuit includes:
A phase control type power supply circuit that inputs the input voltage by turning on and off the switching element based on the phase of the input voltage;
Control means for controlling so that all of the AC input voltage is used at rated load, about half of the AC input voltage is used at medium load, and only a part of the AC input voltage is used at light load. 14. The power supply device according to claim 5, wherein the power supply device includes: A first power supply circuit for generating a first voltage from an input voltage;
A second power supply circuit that generates and outputs a second voltage from the first voltage,
The power supply device, wherein the first voltage is lower than the input voltage. A first power supply circuit that generates a first voltage lower than a peak voltage of the input voltage from an AC input voltage;
A second power supply circuit that generates and outputs a second voltage from the first voltage,
The first power supply circuit is a power supply circuit of a phase control system that turns on and off a switching element based on the phase of the input voltage and inputs the input voltage,
The power supply device, wherein the second power supply circuit is an insulating power supply circuit that generates the second voltage through a transformer. A first power supply circuit that generates a first voltage lower than a peak voltage of the input voltage from an AC input voltage;
A second power supply circuit that generates and outputs a second voltage from the first voltage,
The first power supply circuit is a phase control type power supply circuit that turns on and off the first switching element based on the phase of the input voltage and inputs the input voltage.
The power supply apparatus according to claim 1, wherein the second power supply circuit is a separately-excited chopper type power supply circuit that inputs and outputs the first voltage by turning on and off a second switching element based on an oscillator signal. A first power supply circuit for generating a first voltage from an input voltage;
A second power supply circuit that generates and outputs a second voltage from the first voltage,
The first power supply circuit is a step-down chopper type power supply circuit that turns on and off a switching element and inputs the input voltage,
The power supply device, wherein the second power supply circuit is an insulating power supply circuit that generates the second voltage through a transformer.   The isolated second power supply circuit is a separately-excited / insulated power supply circuit that inputs the first voltage to flow a current on the primary side of the transformer by turning on and off a switching element based on an oscillator signal. The power supply device according to claim 18 or 20, wherein   The power supply device according to claim 21, wherein the transformer is a flyback transformer.   The switching element in the first power supply circuit is a four-layer element in which P-type semiconductors and N-type semiconductors are alternately formed in four layers. Power supply.   The power supply device according to claim 19, wherein the switching element in the second power supply circuit is a MOSFET.   The power supply device according to any one of claims 17 to 24, wherein the first power supply circuit steps down an input voltage of 100 V or more to 30 V or less to make the first voltage.   The power supply device according to any one of claims 17 to 24, wherein the first power supply circuit steps down an input voltage of 100 V or more to 20 V or less to make the first voltage.   25. The first voltage output from the first power supply circuit is a voltage lower than five times the second voltage output from the second power supply circuit. The power supply described.   The power supply according to any one of claims 25 to 27, wherein the first voltage output from the first power supply circuit is higher than the second voltage output from the second power supply circuit. apparatus. The turn ratio of the primary winding and the secondary winding in the transformer of the second power supply circuit is:
(E1 / E _out ) × 0.5 to (E1 / E _out ) × 1.5
Here, E1 is the first voltage input to the second power supply circuit.
E _out is the power supply device according to claim 18,20～22, characterized in that it contains in the range of the second voltage output from the second power supply circuit.   A ratio of an on time during which a current flows to the primary side of the transformer of the second power supply circuit and an off time during which the current is cut off is in a range of 1: 2 to 1: 4 during a standby load. The power supply device according to any one of claims 18 and 20 to 22.   The ratio of the on time during which a current flows to the primary side of the transformer of the second power supply circuit and the off time during which the current is cut off is within a range of 1: 2 to 1: 4 at the output of 10 mW to 50 mW. The power supply device according to any one of claims 18 and 20-22.   The ratio of the on time during which current flows to the primary side of the transformer of the second power supply circuit and the off time during which this current is interrupted is 1: 2 to 1 when the system in which the power supply device is mounted is loaded in the standby mode. 23. The power supply device according to claim 18, wherein the power supply device falls within a range of 4.   25. The control method for the switching element of the second power supply circuit is switched between PWM control and PFM control according to the magnitude of the output load. Power supply.   34. The power supply apparatus according to claim 33, wherein the control is switched to PWM control when the output load is large, and to PFM control when the output load is small.   34. The power supply apparatus according to claim 33, wherein the power supply device is switched to PFM control when the output load is large, and to PWM control when the output load is small.   The means according to any one of claims 17 to 35, further comprising means for changing the magnitude of the first voltage output from the first power supply circuit in accordance with the magnitude of the output load. Power supply. A first control IC that controls the switching element of the first power supply circuit;
A second control IC in which the switching element of the second power supply circuit and a control circuit for controlling the switching element are integrated;
36. The power supply device according to any one of claims 19, 21, 22, 24, and 33 to 35, wherein the second control IC is an IC having a higher withstand voltage structure than the first control IC. A first control circuit for controlling the switching element of the first power supply circuit;
The power supply device according to any one of claims 19, 21, 22, 24, 33 to 35, and 37, comprising: a first auxiliary power supply circuit that supplies power to the first control circuit.   The power supply device according to claim 38, wherein the first auxiliary power supply circuit is configured to generate an output voltage by inputting a voltage obtained by dividing the input voltage of the first power supply circuit by a capacitor. A first drive circuit for driving the switching element of the first power supply circuit;
A second auxiliary power circuit for generating an output voltage by inputting a voltage obtained by dividing the input voltage by a capacitor separately from the first auxiliary power circuit;
40. The power supply apparatus according to claim 38 or 39, wherein power is supplied to the first drive circuit by the second auxiliary power supply circuit. A second control circuit for controlling the switching element of the second power supply circuit;
41. The power supply device according to claim 38, wherein electric power is supplied to the second control circuit by the first auxiliary power supply circuit. A second control circuit for controlling the switching element of the second power supply circuit;
41. The power supply device according to claim 38, wherein the first voltage output from the first power supply circuit is supplied as an operating voltage to the second control circuit.   The power supply apparatus according to any one of claims 1 to 42, wherein the power efficiency with respect to the output load is maximized in a range from no load to a standby load.   The power supply apparatus according to any one of claims 1 to 42, wherein the power efficiency with respect to the output load is maximized in a range of a load of ± 10% in a standby mode of a system in which the power supply apparatus is mounted.   The power supply apparatus according to any one of claims 1 to 42, wherein the power efficiency with respect to the output load is maximized in a range of 20 mW to 100 mW.   The power supply apparatus according to any one of claims 1 to 42, wherein the power efficiency with respect to the output load is 70% or more in a range from no load to a standby load.   The power supply apparatus according to any one of claims 1 to 42, wherein the power efficiency with respect to the output load is 70% or more in a range of standby mode load ± 10% of a system in which the power supply apparatus is mounted. .   The power supply apparatus according to any one of claims 1 to 42, wherein the power efficiency with respect to the output load is 70% or more in a load range of 20 mW to 50 mW.

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