JP2010154605A - Power supply device, electronic circuit, electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device which efficiently utilizes electronic devices and elements included in conventionally used power supply devices are efficiently utilized and selectively supplies high power and low power to a load circuit with a minimum circuit scale. <P>SOLUTION: The power supply device 1 includes: a power source 5 that supplies power to a load circuit 4 by way of either a first path 2 or a second path 3; a switching portion 6 that switches between the first path 2 and the second path 3; a first switch 7 that controls a supply period to be used as a base for the value of first power supplied through the first path 2; a drive unit 10 including an opening/closing switch 8 that controls the timing of opening/closing the first switch 7; and a second switch 9 that controls a supply period to be used as a base for the value of second power supplied through the second path 3. The first power value is higher than the second power value. The first path 2 passes outside the drive unit 10 and the second path 3 passes through the drive unit. The opening/closing switch 8 and the second switch 9 are a common element. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply device that can supply a power value supplied to a load circuit while switching, and is applied to, for example, a power supply circuit, a switching power supply, and a switching power supply circuit.

  2. Description of the Related Art Conventionally, a power supply device such as a switching power supply or a power supply circuit that supplies power (voltage or current) from a power supply to a load circuit is used in an electronic circuit or an electronic device. Such a power supply device may be realized as a device such as a DC-DC converter.

  Recent electronic devices are required to reduce power consumption and standby power, and there are cases where the load circuit operates in a mode that requires a large amount of power and a mode that requires a small amount of power. In particular, most electronic devices include a central processing unit (hereinafter referred to as “CPU”) and software operated by the CPU. The CPU often includes a mode that requires a large amount of power and a mode that requires a small amount of power, and the software often includes a mode that requires a large amount of power and a mode that requires a small amount of power. For example, when the software only performs display, the CPU that operates the software requires a small amount of power, and when the software performs an operation, the CPU that operates the software requires a large amount of power.

  A conventional power supply apparatus includes a power supply, a pulse switch (PWM (Pulse Width Modulation)) that controls a power value from the power supply using a pulse width, and a drive unit that controls opening and closing of the pulse switch. In the power supply device having such a configuration, there is a limit to changing the power value supplied to the load circuit, and power consumption cannot be sufficiently reduced in the low power mode or the standby mode.

Therefore, a plurality of paths for supplying power to the load circuit are provided, and each of the plurality of paths has a different power value that can be supplied, and is a hybrid type power supply apparatus (DC-DC converter) that includes a drive unit that switches between the plurality of paths. ) Has been proposed (see, for example, Patent Document 1).
JP 2007-221981

  In the DC-DC converter disclosed in Patent Document 1, a resistor is connected to a switch that switches a plurality of paths for supplying electric power to shorten the response time.

  However, the DC-DC converter disclosed in Patent Document 1 includes a plurality of paths that supply different power values and elements such as switches that form the paths, and are individually provided for each path. There is a problem that costs increase. Furthermore, the individual circuit is used only for power supply in each path, and there is a problem that the use efficiency of the electronic element is impaired. As a result, there also arises a problem that power consumption near the power source increases.

  In addition, the technique disclosed in Patent Document 1 has a problem that it is necessary to form more elements and wirings in the vicinity of the power source, and it is difficult to cope with noise.

  In view of these problems, the present invention provides a load circuit with high power and low power with a minimum circuit scale while efficiently utilizing electronic elements and elements included in a conventionally used power supply apparatus. An object of the present invention is to provide a power supply device that can be supplied in a separated manner.

  In view of the above problems, a power supply apparatus according to the present invention includes a power source that supplies power to a load circuit via a first path and a second path different from the first path, a first path, and a second path. A switching unit that switches between the paths, a first switch that controls a supply period that serves as a reference for the first power value supplied from the first path, and a drive unit that includes an opening and closing switch that controls the timing of opening and closing the first switch; A second switch that controls a supply period serving as a reference for the second power value supplied from the second path, wherein the first power value is greater than the second power value, and the first path is driven The second path passes through the inside of the drive unit, and the open / close switch and the second switch are common elements.

  The power supply device of the present invention can supply large power and small power to the load circuit according to the necessity of the load circuit while minimizing the increase in circuit scale. Of course, the circuit area and cost can also be reduced.

  In addition, since the drive unit included in the switching power supply in consideration of the influence of noise is used as it is, it is difficult to cause the influence of noise.

  A power supply device according to a first aspect of the present invention includes a power source that supplies power to a load circuit via one of a first path and a second path different from the first path, a first path, A switching unit that switches between two paths, a first switch that controls a supply period that is a reference for the first power value that is supplied from the first path, and a drive unit that includes an opening / closing switch that controls the opening / closing timing of the first switch And a second switch for controlling a supply period serving as a reference for the second power value supplied from the second path, wherein the first power value is larger than the second power value, and the first path is While passing through the outside of the driving unit, the second path passes through the inside of the driving unit, and the open / close switch and the second switch are common elements.

  With this configuration, the first power value that is high power and the second power value that is low power can be supplied to the load circuit via different paths without increasing the circuit scale. In addition, since the power value can be controlled by an element that matches the power value, unnecessary loss and power consumption can be suppressed.

  In the power supply device according to the second aspect of the present invention, in addition to the first aspect, the first switch has a first pulse switch that switches between supply and stop of power according to time, and the second switch The first pulse switch and the second pulse switch control the supply period by the pulse width, and the first power value and the second power value are determined by the pulse width. It is determined.

  With this configuration, the first power value and the second power value are accurately controlled.

  In the power supply device according to the third aspect of the present invention, in addition to the second aspect, each of the first pulse switch and the second pulse switch includes a MOS transistor whose opening / closing is controlled by an input signal to the gate terminal. Have.

  With this configuration, the open / close period for determining the pulse width can be easily controlled.

  In the power supply device according to the fourth aspect of the present invention, in addition to the third aspect, the second pulse switch has a pair of MOS transistors connected in series.

  With this configuration, the open / close period for determining the pulse width can be easily controlled.

  In the power supply device according to the fifth aspect of the present invention, in addition to any one of the third to fourth aspects, when the switching unit selects the first path, the output of the open / close switch is the first The gate input of the MOS transistor included in the pulse switch is used to control the open / close period of the first pulse switch. The open / close period of the first pulse switch determines the supply period and the first power value. When the second path is selected, the open / close period of the second pulse switch determines the supply period and determines the second power value.

  With this configuration, the first power value that is high power and the second power value that is low power can be easily controlled. Moreover, since the 2nd electric power value which is small electric power is controlled by the opening / closing period of the 2nd pulse switch which is a small element, switching loss can be suppressed.

  In the power supply device according to the sixth aspect of the present invention, in addition to any of the first to fifth aspects, the load circuit requires any power value of the first power value and the second power value. And a detection unit for detecting whether or not.

  With this configuration, the power supply device can reliably control the power value to be supplied.

  In the power supply device according to the seventh aspect of the present invention, in addition to the sixth aspect, the detection unit can detect any power among the first power value and the second power value based on the operation mode of the load circuit. Detect whether a value is needed.

  With this configuration, the power supply device can supply power reflecting the operation content of the load circuit.

  In the power supply device according to the eighth aspect of the present invention, in addition to any one of the first to seventh aspects, the controller that controls the selection of the route from the first route and the second route in the switching unit, In addition.

  With this configuration, path switching can be easily performed. In particular, the route is appropriately switched by following the detection result of the detection unit.

  In addition to any one of the first to eighth inventions, the power supply apparatus according to the ninth invention of the present invention further includes a switch control unit that controls the opening / closing timing of the second switch.

  With this configuration, the supply period serving as a basis for controlling the first current value and the second current value is appropriately controlled.

  The power supply apparatus according to a tenth aspect of the present invention further includes a filter for smoothing an input signal to the load circuit in addition to any of the first to ninth aspects.

  With this configuration, the signal to the load circuit is smoothed and no malfunction occurs in the load circuit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  Note that the power supply device may be realized by any of an electronic circuit, a semiconductor integrated circuit, and an electronic element, and a part of the control may be realized by a software program. Moreover, even if it provides only with an electric power supply apparatus, it may be supplied in the state combined with the other electronic circuit.

(Embodiment 1)
First, an overall outline of the power supply apparatus according to the first embodiment will be described with reference to FIG. 1. FIG. 1 is a block diagram of the power supply apparatus according to the first embodiment of the present invention.

(Overview)
The power supply device 1 includes a power source 5 that supplies power to the load circuit 4 via one of the first path 2 and the second path 3, and a switching unit 6 that switches between the first path 2 and the second path 3. A first switch 7 that controls the first power value supplied from the first path 2, an open / close switch 8 that controls the open / close timing of the first switch 7, a drive unit 10 that includes the open / close switch 8, and a second A second switch 9 for controlling the second power value supplied from the path 3 is provided. Here, the open / close switch 8 and the second switch 9 are the same elements and are common elements.

  In FIG. 1, the power supply device 1 including the load circuit 4 is shown, but the power supply device 1 may or may not include the load circuit 4. For example, a portion other than the load circuit 4 may be regarded as a power supply device, and the state including the load circuit 4 may be regarded as an electronic circuit.

  As is clear from FIG. 1, the first path 2 is a path that is connected to the load circuit 6 from the power source 5 in the shortest time and passes outside the drive unit 10. On the other hand, the second path 3 passes through the inside of the drive unit 10 from the power supply 5 and is connected to the load circuit 4. If the power value supplied from the first path 2 is the first power value and the power value supplied from the second path 3 is the second power value, the first power value is larger than the second power value.

  Here, the load circuit 4 may require a large amount of power or a small amount of power.

  When the load circuit 4 requires high power, the first path 2 that supplies the first power value that is high power is selected, and when the load circuit 4 requires low power, the low power is required. A second path 3 for supplying a certain second power value is selected.

  As shown in FIG. 1, the switching unit 6 has two switches. When the two switches are short-circuited, the first path 2 that connects the power source 5 and the load circuit 4 becomes conductive. The first power value supplied from the power source 5 to the load circuit 4 via the first path 2 is controlled by opening and closing the first switch that connects the first path 2 and the ground 11.

  On the other hand, when the two switches of the switching unit 6 are opened, the second path 3 conducts from the power source 5 to the load circuit 4. The second path 3 is controlled to be short-circuited and opened by the second switch 9 to control the second power value supplied to the load circuit 4.

  When the load circuit 4 requires only a small amount of power, the second power value that is less than the power supplied to the load circuit 4 using the first path 2 that supplies the first power value that is a large amount of power. Supplying power to the load circuit 4 using the second path 3 for supplying power is superior in terms of loss reduction and power consumption reduction.

  For example, when power is supplied to the load circuit 4 via the first path 2, the switching unit 6 is short-circuited, and the second path 2 that connects the power supply 5 to the load circuit 4 in the shortest is conductive. . The second power value supplied to the load circuit 4 through the conductive second path 2 is controlled by the opening / closing period of the first switch 7 connected to the ground 11 in the middle of the second path 2. That is, when the first switch 7 is in a connected state, the second path 2 to the ground 11 are in a conductive state, and no power is supplied to the load circuit 4, and conversely, when the first switch 7 is in an open state, The power supply 5 and the load circuit 4 are in a conductive state, and power is supplied to the load circuit 4. At this time, the first switch 7 forms a path that directly conducts the power supply 5 and the ground 11, and has a role of releasing power (high power) based on the first power value from the power supply 5 to the ground 11. Therefore, a large element is required from the viewpoint of breakdown voltage and operation performance. On the other hand, since the opening / closing switch 8 (that is, the second switch 9) only needs to switch the opening / closing of the first switch 7, a small element is sufficient in terms of breakdown voltage and operation performance.

  When power is supplied to the load circuit 4 via the second path 3, the switching unit 6 is opened, and the second path 3 passing through the drive unit 10 conducts. In the second path 3, the conduction between the power source 5 and the load circuit 6 is controlled during the opening / closing period of the second switch 9. That is, the power supply from the power supply 5 to the load circuit 4 is stopped while the second switch 9 is open, and the power supply 5 to the load circuit 4 is stopped while the second switch 9 is short-circuited. Electric power is supplied, and the second electric power value is determined by the stop period and the supply period. Since the 2nd electric power value supplied by the 2nd path | route 3 is small, the 2nd switch 9 is enough for the 2nd switch 9 also from this point.

  That is, the first switch 7 requires a large element, and the second switch 9 needs a small element. The larger the element that constitutes the switch, the greater the loss during opening and closing of the switch, so the power consumption of the entire power supply device 1 increases. For this reason, when the load circuit 4 requires only small power, the power value is controlled by the second switch 9 which is a small element, rather than by the first switch 7 which is a large element. Is preferred.

  From the above, in order to switch and supply large power and small power to the load circuit 4 that requires large power or small power while preventing loss and increase in power consumption, the first switch 7 which is a large element is used. It is preferable that the first path 2 using the switch and the second path 3 using the second switch 9 which is a small element are switched.

  As described above, the power supply device 1 switches the first path 2 and the second path 3 by the switching unit 6 and controls the first power value supplied from the first path 2 by the first switch 7 ( The first switch 7 is controlled by the open / close switch 8), and the second power value supplied from the second path 3 is controlled by the second switch 9.

  Further, since the second switch 9 uses the same elements as the opening / closing switch 8 that controls the opening / closing timing of the first switch 7, it is not necessary to add an extra circuit element. In the first place, the second switch 9 is an opening / closing switch 8 which is an essential element for the opening / closing timing of the first switch 7, and the second switch 9 necessary for controlling the current value of the second path 3 is This does not lead to additional circuit elements.

  Further, when the second path 3 for supplying low power is configured via the second switch 9, the second switch 9 is the opening / closing switch 8 included in the drive unit 10 that originally exists. Noise countermeasures on electronic circuits are also taken. For this reason, in the supply of the 2nd electric power value by the 2nd path | route 3 using the 2nd switch 9 (open / close switch 8), generation | occurrence | production of an excess noise can also be prevented.

  As described above, the power supply apparatus according to the first embodiment prevents the increase in circuit scale, the increase in noise, the increase in loss, and the increase in power consumption, while supplying the load circuit 4 with high power and low power as necessary. Can be switched.

  Next, the detail of each part is demonstrated.

(Power supply)
The power source 5 generates actual power and supplies the power to the load circuit 4. The power source 5 is a household power source, a battery or a battery.

(Load circuit)
The load circuit 4 is supplied with power from the power source 5 by the power supply device 1.

  The load circuit 4 includes an electronic circuit, a semiconductor integrated circuit, a CPU, a DSP (Digital Signal Processor), and the like that perform predetermined operations upon receiving power. Regardless of the form the load circuit 4 has, the load circuit 4 receives power and performs a predetermined operation.

  Since the load circuit 4 includes various operations, the required power value varies depending on the operation content. When the operation is complicated, the load circuit 4 requires a large amount of power, and when the operation is simple, the load circuit 4 requires a small amount of power.

  Here, when the load circuit 4 is a CPU, the load circuit 4 often operates as a software program. The software program may perform a complex operation or a simple operation depending on the processing contents of the user. For example, when the software program only displays, the CPU that operates the software program requires a small amount of power, and when the software program performs an operation, the CPU that operates the software program requires a large amount of power. Cost. In particular, when the load circuit 4 is a CPU, since the change in the operation of the software program is severe, the change in the power required by the load circuit 4 is also severe.

  As described above, the value of power required by the load circuit 4 can frequently change according to the change in the operation content. Since the power supply 5 provided in the power supply apparatus 1 is a household power supply, a battery, or a battery, it is difficult for the power supply 5 itself to change the power value to be supplied. The power supply device 1 controls the power value to the load circuit 4 by switching the open / close period (conduction period) of the path from the power source 5 to the load circuit 4. However, the load circuit 4 may require a large amount of power and a small amount of power, and it is efficient to separate the loss in switching for switching the path open / close period between the case of large power and the case of small power. .

  For this reason, when the load circuit 4 requires large electric power, electric power is supplied by the 1st path | route 2 which can be switched by a large sized element. When the load circuit 4 requires small electric power, electric power is supplied by the second path 3 that can be switched by a small element.

  Even if the load circuit 4 is an electronic circuit other than the CPU, a semiconductor integrated circuit, or the like, the power value required by the load circuit 4 can vary with time.

  The load circuit 4 includes the term “circuit”. However, in addition to a physical circuit, the load circuit 4 may include a software program in part or in whole, or may include a memory, a ROM, and the like.

(First route, second route, switching unit)
The power supply device 1 includes a first path 2 and a second path 3 as power supply paths from the power supply 5 to the load circuit 4. The first path 2 supplies power based on the first power value, which is high power, to the load circuit 4. The second path 3 supplies power based on the second power value, which is low power, to the load circuit 4. Here, the first power value is larger than the second power value.

  The switching unit 6 switches between the first route 2 and the second route 3. As shown in FIG. 1, the switching unit 6 includes a switch on the first path 2 and a switch in front of the first switch 7. When the switch on the first path 2 of these two switches is short-circuited and the switch in front of the first switch 7 is short-circuited to the first switch side, the first path 2 from the power source 5 to the load circuit 4 becomes conductive. To do. At this time, since the switch in front of the first switch 7 is short-circuited with the first switch, the second path 3 is opened as opposed to the first path 2 conducting. This is because the switch provided before the first switch 7 is switched depending on whether it is connected to the first switch 7 or the second path 3. Further, the power source 5 to the first switch 7 conduct through the driving unit 10.

  On the other hand, when the switch on the first path 2 among the two switches of the switching unit 6 is opened and the switch in front of the first switch 7 is short-circuited to the second path 3 side, the load circuit from the power source 5 The first path 2 up to 4 is cut off, and the second path 3 connected from the power source 5 to the load circuit 4 via the drive unit 10 conducts.

  The switching unit 6 includes two switches. However, the switching unit 6 may include other elements, and the switches may be realized by MOS transistors. Although not shown in FIG. 1, a control unit that performs switching of the switches included in the switching unit 6 may be provided.

  In any case, the switching unit 6 switches the power supply path from the power source 5 to the load circuit 4 to either the first path 2 or the second path 3.

(First switch, open / close switch, second switch)
The first switch 7 controls a supply period serving as a reference for a first power value that is a value of power supplied from the first path 2 to the load circuit 4. The first switch 7 is a switch that determines whether the line connecting the first path 2 and the ground 11 is short-circuited or opened. When the first switch 7 is short-circuited, the first path 2 and the ground 11 Is connected, and the power from the power source 5 escapes to the ground 11. That is, power is not supplied to the load circuit 4 during this period. The opening / closing period of the first switch 7 is controlled by the opening / closing switch 8.

  On the other hand, the second switch 9 is the same element as the open / close switch 8, and the open / close switch 8 is used.

  The second switch 9 is originally a switch for opening and closing the first switch 7, but determines a supply period in the case of supplying power via the second path 3. Since the second switch 9 can directly control the short circuit and the open circuit of the second path 3, the second path 3 from the power supply 5 to the load circuit 4 is conductive when the second switch 9 is short circuited. When the second switch 9 is open, the second path 3 from the power source 5 to the load circuit 4 is blocked.

  Thus, the first path 2 determines the conduction period between the power supply 5 and the load circuit 4 by the combination of the open / close switch 8 and the first switch 9. In the second path 3, the conductive period between the power supply 5 and the load circuit 4 is determined by the second switch 9.

  Here, each of the first switch 7 and the second switch 9 may include a first pulse switch and a second pulse switch that determine an open / close period with a pulse width.

  The pulse switch controls the open / close period of the switch by the pulse width. In other words, the period in which the switch is short-circuited (closed state) and the period in which the switch is open (open state) are each represented as a width on the time axis on the timing chart.

  For example, the power value supplied to the load circuit 4 is determined by integration of pulses indicating a period during which power is supplied in a certain predetermined period. Since the pulse switch can control the open / close period of the switch by the pulse width, the pulse switch can easily control the power value.

  For example, the longer the pulse width that causes a short circuit, the longer the conduction period between the power source 5 and the load circuit 4, and thus the integrated value increases and the power value in the predetermined period increases. On the contrary, if the open pulse width is long, the cutoff period between the power source 5 and the load circuit 4 is lengthened accordingly, so that the integral value becomes small and the power value in the predetermined period becomes small.

  In actual electronic circuits and electronic devices, the load circuit and the power supply are not directly conducted, but the conduction period between the power supply and the load circuit is finely controlled with the pulse switch as described above on the time axis. Thus, the power value to the load circuit is determined by the integral value in the predetermined period.

  The pulse switch is also preferably a MOS transistor whose opening / closing is controlled by gate input.

  The MOS transistor has three terminals of a gate, a source, and a drain, and the source and the drain are short-circuited or opened depending on the value of the gate input. A MOS transistor can be easily built into a semiconductor integrated circuit, and is an ideal switch that can control opening and closing only by controlling a gate input. In addition, since the withstand voltage and the operation performance can be controlled by adjusting the transistor size of the MOS transistor, if the first switch 7 and the second switch 9 (that is, the open / close switch 8) are composed of MOS transistors, The switch can easily handle the voltage and power that the switch should handle.

  2 and 4 are block diagrams of the power supply apparatus according to Embodiment 1 of the present invention. In both FIG. 2 and FIG. 4, the first switch 7 and the second switch 9 include MOS transistors. The first switch 7 includes a MOS transistor 20, and the second switch 9 includes a pair of MOS transistors 21 and 22 connected in series.

  FIG. 2 shows a case where the switching unit 6 selects the first route 2, and FIG. 4 shows a case where the switching unit 6 selects the second route 3. By providing such a MOS transistor in the first switch 7 and the second switch 9, an open / close period having a pulse width can be easily formed, and the power supply device 1 can easily set the power value to the load circuit 4. Can be controlled.

(Power supply in the first route)
Next, the power supply operation in the first path will be described. Here, a case where the first switch 7 and the second switch 9 are MOS transistors will be described. First, an operation in which the power supply 5 supplies power to the load circuit 4 through the first path 2 will be described with reference to FIGS. FIG. 3 is a time chart showing power supply through the first path in the first embodiment of the present invention.

  As shown in FIG. 2, the two switches of the switching unit 6 are short-circuited, and the first path 2 conducts from the power source 5 to the load circuit 4. Further, since the drive unit 10 and the first switch 7 are also conductive, the first switch 7 is controlled by the open / close switch 8 (second switch 9) of the drive unit 10.

  The first switch 7 includes a MOS transistor 20, and the output of the drive unit 10 is input to the gate terminal of the MOS transistor 20. The drive unit 10 includes an open / close switch 8, and the open / close switch 8 includes a pair of MOS transistors connected in series.

  The drain terminals of the pair of MOS transistors 21 and 22 are connected to each other, and an output from the drain terminal is input to the gate terminal of the MOS transistor 20. The short circuit and open (ON and OFF) of the MOS transistor 20 are determined by the voltage value (whether it is a Hi level voltage or a Lo level voltage) input to the gate terminal. For this reason, the short circuit and the open circuit of the MOS transistor 20 are determined by the short circuit and the open circuit of the pair of MOS transistors 21 and 22. Here, when the MOS transistor 20 is short-circuited, the line connecting the first path 2 and the ground 11 conducts, and the power from the power source 5 flows to the ground 11, and the load circuit 4 receives power. Not supplied directly. This period is a non-power supply period. On the other hand, when the MOS transistor 20 is open, the line connecting the first path 2 and the ground 11 is cut off, so that power from the power source 5 is supplied directly to the load circuit 4. This period is a power supply period.

  The power value (first power value) that the load circuit 4 obtains in a predetermined period is determined by the integrated value of the non-supply period and the supply period.

  Each of the pair of MOS transistors 21 and 22 is preferably a MOS transistor that operates symmetrically. That is, when the MOS transistor 21 is short-circuited (ON), the MOS transistor 22 is open (OFF), and when the MOS transistor 21 is open (OFF), the MOS transistor 22 is short-circuited (ON). It is preferable. Due to this symmetry, when only the MOS transistor 21 is short-circuited, a signal based on the voltage of the power supply 5 is supplied to the output of the drive unit 10 and only the MOS transistor 22 is short-circuited. This is because a signal based on the ground voltage is supplied to the output of the drive unit 10. The output of the drive unit 10 is directly input to the gate terminal of the MOS transistor 20 constituting the first switch 7.

  In the pair of MOS transistors 21 and 22, when the MOS transistor 21 is short-circuited (ON), the voltage from the power supply 5 is directly input to the gate terminal of the MOS transistor 20. By inputting the voltage from the power source to the gate terminal of the MOS transistor 20 as it is, a Hi level signal is input to the gate terminal of the MOS transistor 20.

  When the MOS transistor 20 is an N-MOS transistor, the MOS transistor 20 is short-circuited (ON) when a Hi level signal is input to the gate terminal. For this reason, when the MOS transistor 20 is an N-MOS transistor and the MOS transistor 21 is short-circuited, the MOS transistor 20 is short-circuited. When the MOS transistor 20 is in a short-circuited state, the line from the first path 2 to the ground 11 conducts, and power escapes from the power source 5 to the ground 11. For this reason, the power source 5 cannot supply power to the load circuit 4. That is, a period in which power is not supplied in a predetermined period occurs.

  On the other hand, in the pair of MOS transistors 21 and 22, when the MOS transistor 22 is short-circuited (ON) (the MOS transistor 21 is open), the ground voltage is input to the gate terminal of the MOS transistor 20. That is, the Lo level signal is input to the gate terminal of the MOS transistor 20. When the MOS transistor 20 is an N-MOS transistor, the MOS transistor 20 is opened (OFF) when a Lo level signal is input to the gate terminal. Therefore, when the MOS transistor 20 is an N-MOS transistor and the MOS transistor 22 is short-circuited, the MOS transistor 20 is opened. When the MOS transistor 20 is in an open state, the line from the first path 2 to the ground 11 is cut off, and power from the power source 5 is supplied directly to the load circuit 4. That is, a period during which power is supplied in a predetermined period occurs.

  As described above, the output of the opening / closing switch 8 (= second switch 9) included in the drive unit 10 is switched between the Hi level signal and the Lo level signal within the predetermined period. A supply period in which power is supplied and a non-supply period in which power is not supplied are switched. The integral value of the power supply period in the predetermined period is the power value supplied to the load circuit 4 (in this case, the first power value based on the supply through the first path 2).

  The 1st electric power value by the 1st path | route 2 is demonstrated using FIG.

  The time chart of FIG. 3 shows the output of the open / close switch 8 (second switch 9), the output of the first switch 7, the input signal to the load circuit 4, and the first power value from the top. In FIG. 3, when the open / close switch 8 is short-circuited, the first switch 7 is opened. Since the switching unit 6 is short-circuited, the voltage signal shunted from the power source 5 is supplied to the open / close switch 8. However, the current value of the signal output from the open / close switch 8 is smaller than the current value flowing through the open / close switch 8 as a second path described later.

  The opening / closing of the first switch 7 is determined according to the signal change of the opening / closing switch 8. The power from the power source 5 is supplied to the load circuit 4 in accordance with the opening and closing of the first switch 7. Here, the power supplied to the load circuit 4 in a predetermined period in the time chart of FIG. 3 is determined by the integral value of the power supplied to the load circuit 4, and the first power value at the bottom of the time chart is: This integral value is shown.

  Since the first power value is an integral value of the power controlled by the switch 7 corresponding to the high power value, the value is large as shown in FIG. Here, if the opening period of the first switch 7 is long, the integrated value of the power supplied to the load circuit 4 within a predetermined period becomes large. Therefore, the magnitude of the first power value depends on the opening / closing operation of the first switch 7 ( That is, it is determined by the opening / closing operation of the opening / closing switch 8.

  As shown in the time chart of FIG. 3, the first power value to the load circuit 4 is determined by the opening / closing operation of the opening / closing switch 8 and the first switch 7.

  The Hi level signal is a signal having a voltage higher than a predetermined potential, and the Lo level signal is a signal having a voltage lower than the predetermined potential, and is a signal divided by a voltage threshold value that controls the operation of the MOS transistor. It is. Further, a short circuit of the MOS transistor or the switch is synonymous with the “ON” state, and an open of the MOS transistor or the switch is synonymous with the “OFF” state.

  Further, when the MOS transistor 20 is a P-MOS transistor, the operation reverse to that of the N-MOS transistor is performed. That is, the P-MOS transistor is opened when a Hi level signal is input to the gate terminal, and the N-MOS transistor is shorted when a Lo level signal is input to the gate terminal. That is, when the pair of MOS transistors 21 is short-circuited, the MOS transistor 20 is opened, and when the pair of MOS transistors 22 is short-circuited, the MOS transistor 20 is short-circuited. Thus, when the MOS transistor 20 is a P-MOS transistor, the supply period and non-supply period from the power supply 5 to the load circuit 4 are opposite to those of the N-MOS transistor.

  Further, the MOS transistor 20 included in the first switch 7 needs to correspond to a large power supplied from the power supply 5 to its gate terminal and source terminal, and therefore requires a large element size. For this reason, the element size of the MOS transistor 20 is large. For this reason, if a switching operation of the MOS transistor 20 is required when supplying small power, unnecessary loss, unnecessary noise, and unnecessary power consumption are caused. On the other hand, the pair of MOS transistors 21 and 22 included in the second switch 9 is connected to the output of the power source 5 at the source terminal, but only needs to be opened and closed, so that a large breakdown voltage is not required and a small element Size may be sufficient.

For this reason, when supplying the first power value (supplied via the first path 2) which is large power, it is preferable to control the power value by the first switch 7 having a large element size. When supplying the second power value which is a small power, the power value is preferably controlled by the second switch 9 having a small element size via the second path 3.

  Although the configuration in which the open / close switch 8 includes the pair of MOS transistors 21 and 22 has been described, the open / close switch 8 may have other configurations.

(Power supply in the second route)
Next, power supply to the load circuit 4 in the second path 3 will be described with reference to FIGS. 4 and 5. FIG. 4 is a block diagram of the power supply circuit according to Embodiment 1 of the present invention, and FIG. 5 is a time chart showing power supply through the second path.

  As shown in FIG. 4, the two switches of the switching unit 6 are open, the first path is cut off, and the second path 3 from the power source 5 via the driving unit 10 is conducted. The actual conduction of the second path 3 is controlled by the opening / closing operation of the second switch 9 included in the driving unit 10.

  The second switch 9 is a common element to the open / close switch 8 and is not distinguished physically or circuitally. The second switch 9 includes a pair of MOS transistors 21 and 22 as described with reference to FIG. Of course, the second switch 9 may have other configurations.

  The drain terminals of the pair of MOS transistors 21 and 22 are connected to each other, and an output from the drain terminal is input to a line connected to the load circuit 4.

  Each of the pair of MOS transistors 21 and 22 is preferably a MOS transistor that operates symmetrically. That is, when the MOS transistor 21 is short-circuited (ON), the MOS transistor 22 is open (OFF), and when the MOS transistor 21 is open (OFF), the MOS transistor 22 is short-circuited (ON). It is preferable. Due to this symmetry, when only the MOS transistor 21 is short-circuited, a signal based on the voltage of the power supply 5 is supplied to the output of the drive unit 10, and only the MOS transistor 22 is short-circuited. This is because a signal based on the ground voltage is supplied to the output of the drive unit 10. Since the pair of MOS transistors 21 and 22 are divided into a case where the output from the power supply 5 is transmitted and a case where the ground voltage is transmitted, the second path 3 is configured to supply power to the load circuit 4 only by opening and closing the second switch 9. The supply period and the non-supply period can be switched.

  When the MOS transistor 21 is short-circuited and the MOS transistor 22 is open, the second switch 9 outputs a signal from the power supply 5. That is, power is supplied from the power supply 5 to the load circuit 4 during a period in which the MOS transistor 21 is short-circuited (this is a period in which the second switch 9 is ON). That is, under this condition, a power supply period occurs.

  On the other hand, when the MOS transistor 21 is opened and the MOS transistor 22 is short-circuited, the second switch 9 outputs a signal based on the ground voltage. For this reason, during the period in which the MOS transistor 21 is open (this is the period in which the second switch 9 is OFF), power from the ground is supplied to the load circuit 4. That is, under this condition, a non-power supply period occurs.

  The second power value supplied to the load circuit 4 via the second path 3 is determined by an integral value of the power supply period and the non-supply period. The determination of the second power value is as shown in the time chart of FIG.

  The 1st electric power value by the 2nd path | route 3 is demonstrated using FIG.

  The time chart of FIG. 5 shows from the top the output of the second switch 9, the input signal to the load circuit 4, and the power applied to the load circuit 4. In FIG. 5, power is supplied from the power source 5 to the load circuit 4 during the period when the open / close switch 8 is short-circuited. The second path 3 needs to increase the number of times of switching in a predetermined period in order to supply the second power value which is a small power (the second power value is obtained by integrating the power supply period and the non-supply period. Because it is fixed). That is, it is necessary to increase the number of times the second switch 9 is switched. However, since the second switch 9 is composed of a small element with a small withstand voltage and small amplification, even if the number of switching is large, the loss and the power consumption loss are small.

  As shown in FIG. 5, the switching of the second switch 9 is fine and often performed. Further, since the current value of the signal output from the switch 9 is also small, the power value of the output signal of the second switch 9 is also small. The output of the second switch 9 becomes the input to the load circuit 4 as it is. Also in FIG. 5, the output of the second switch 9 and the input signal to the load circuit 4 have corresponding waveforms. The integral value of the power supplied to the load circuit 4 within the predetermined period becomes the second power value.

  As a result, as shown in FIG. 5, the second power value having a value lower than the first power value is supplied to the load circuit 4.

  As described above, the second power value is determined, and a small amount of power is supplied to the load circuit 4.

  In this way, when the load circuit 4 requires a large amount of power, the power having the first power value controlled by the open / close period of the open / close switch 8 and the first switch 7 is transmitted via the first path 2. It is supplied to the load circuit 4. On the other hand, when the load circuit 4 requires small power, the power having the second power value controlled by the opening / closing operation of the second switch 9 is supplied to the load circuit 4 via the second path 3. The

  Further, each of the first switch 7 and the second switch 9 is a pulse switch that outputs a signal determined by a pulse width (in particular, a MOS whose opening / closing (ON / OFF) is controlled by an input signal to the gate terminal) By being a transistor, the first power value and the second power value can be controlled by opening and closing these pulse switches. For this reason, the power value required by the load circuit 4 can be precisely controlled.

(Smoothing the input to the load circuit)
Next, a power supply apparatus including a filter that smoothes an input signal to the load circuit 4 will be described.

  FIG. 6 is a block diagram of the power supply apparatus according to Embodiment 1 of the present invention. The power supply apparatus of FIG. 6 includes a filter that smoothes an input signal input to the load circuit 4. The filter includes an inductor 30 and a capacitor 31, and smoothes an input signal by the operation of the inductor 30 and the capacitor 31. Here, since the inductor 30 and the capacitor 31 are connected in parallel, these are so-called “low-pass filters (low-pass filters)”. Since the high frequency component is cut off, extra noise is not applied and a smoothed signal is input to the load circuit 4. Since the load circuit 4 is an aggregate of electronic circuits, receiving a signal with attenuated noise is important for proper operation.

  The load circuit 4 performs an appropriate operation by receiving an input signal smoothed by the inductor 30 and the capacitor 31. Since the input signal is smoothed, the load circuit 4 is less susceptible to noise, and malfunctions are prevented.

(Power supply device having control of switching unit and second switch)
Next, a switching unit 6 selects one of the first route 2 and the second route 3, and a switch control unit that controls the opening / closing operation of the opening / closing switch 8 and the second switch 9 which are common elements. 7 for explanation. FIG. 7 is a block diagram of the power supply apparatus according to Embodiment 1 of the present invention.

  The control unit 40 controls route selection (selection of either the first route 2 or the second route 3) in the switching unit 6.

  The switching unit 6 switches between the first path 2 and the second path 3 by opening and closing two switches included in the switching unit 6. At this time, the control unit 40 controls the switch opening and closing in the switching unit 6. For example, when the control unit 40 is given information that the load circuit 4 requires high power (this is set to the high power mode), the control unit 40 short-circuits two switches of the switching unit 6, The first path 2 is made conductive. Conversely, when the control unit 40 is informed that the load circuit 4 requires low power (this is set to the low power mode), the control unit 40 opens the two switches of the switching unit 6. The second path 3 is made conductive.

  At this time, it is also preferable that a detection unit that detects information related to the high power mode and the low power mode and supplies the information to the control unit 40 is further provided. The detection unit is a block having information for controlling the load circuit 4, and determines whether the operation mode in the load circuit 4 is the high power mode or the low power mode based on the information to be controlled. The information is output to the control unit 40.

  Thus, the route selection in the switching unit 6 is appropriately performed by the control unit 40.

  The power supply apparatus 1 may have a switch control unit 41 separately.

  The switch control unit 41 controls the opening / closing operation of the second switch 9 (that is, the opening / closing switch 8). The second switch 9 has a case where the opening / closing operation of the first switch 7 is controlled as the opening / closing switch 8 and a case where the switching between conduction and blocking of the second path 3 is controlled. At this time, the switch control unit 41 controls the opening / closing timing of the second switch 9 using information on the path selected by the switching unit 6 and information on the power value required by the load circuit 4. For this reason, the switch control unit 41 may obtain the information from the control unit 40 or the detection unit and control the opening / closing timing of the second switch 9. This is because the power value supplied to the load circuit 4 is determined by the opening / closing timing of the second switch 9.

  As described above, the power supply device 1 including the control unit 40 and the switch control unit 41 can supply the power value according to the power value required by the load circuit 4.

(Power supply device having a detection unit)
Next, a power supply apparatus having a detection unit will be described with reference to FIG.

  FIG. 8 is a block diagram of the power supply apparatus according to Embodiment 1 of the present invention.

  As is clear from FIG. 8, the power supply device 1 further includes a detection unit 42 that detects a power value required by the load circuit 4. For example, the detection unit 42 detects whether the load circuit 4 requires the first power value or the second power value. At this time, when the load circuit 4 is a processor such as a CPU or DSP that operates the software program, the detection unit 42 detects the required power in the load circuit 4 based on the operation mode specified by the software program. . Furthermore, the detection unit 42 notifies the control unit 40 of either the detected first power value or second power value. At this time, the detection unit 42 may notify not only the selection result of the first power value or the second power value but also the power value to be actually supplied. Upon receiving this notification result, the control unit 40 controls the switching of the switching unit 6 and determines the opening / closing timing of the second switch 9 via the switch control unit 41.

  For example, when the software program performs image processing, the processing operation is complicated and the required power becomes large. Therefore, the detection unit 42 assumes that the load circuit 4 requires the first power value. To detect. On the other hand, when the software program only saves the file, the processing operation is simple and the required power is small. Therefore, the detection unit 42 requires that the load circuit 4 It detects that it is an electric power value. Moreover, you may detect the specific electric power value in a 1st electric power value and a 2nd electric power value.

  Of course, the detection unit 42 may detect the power value required by the load circuit 4 based on a mode other than the operation mode of the software program. For example, when the load circuit 4 enters an energy saving mode for reducing power consumption, the detection unit 42 detects that the load circuit 4 requires the second power value.

  According to the detection result of the detection unit 42, the control unit 40 controls the switching unit 6 to select the first route 2 and the second route 3. Similarly, the switch control unit 41 controls the opening / closing timing of the second switch 9 according to the detection result of the detection unit 42. For example, when the detection unit 42 detects the required power value in the load circuit 4 as a large value, the switch control unit 41 controls the opening / closing timing of the second switch 9 so that the power supply period becomes longer. .

  As described above, the detection unit 42 detects the power value required by the load circuit 4, so that the power value supplied to the load circuit 4 by the power supply device 1 can be accurately controlled. In particular, when the load circuit 4 requires a large amount of power, the first power value can be controlled by the first switch 7 having a large element size that can support the control of the large amount of power, and the load circuit 4 requires a small amount of power. In this case, the second power value can be controlled by the second switch 9 having a small element size suitable for small power control.

  As a result, even if the power values to be supplied are different, the power supply device 1 does not increase noise, loss, and power consumption. The second power value supplied through the second path 3 is controlled by the second switch 9, but the second switch 9 itself is an element that is originally necessary for controlling the opening and closing of the first switch 7. is there. For this reason, the power value required by the load circuit 4 can be supplied without increasing the circuit scale.

  The power supply device 1 described with reference to FIGS. 1 to 8 supplies power to the load circuit 4 via any one of the first path 2 and the second path 3 different from the first path 2. A power source 5, a switching unit 6 for switching between the first path 2 and the second path 3, a first pulse switch for generating a pulse timing for determining a first power value supplied from the first path 2, and a first pulse A drive unit 10 including an open / close pulse switch for controlling the opening / closing timing of the switch; and a second pulse switch for generating a pulse timing for determining a second power value supplied from the second path 3; The value is greater than the second power value, and the first path 2 passes through the outside of the driving unit 10 and the second path 2 passes through the inside of the driving unit 10 to open and close the open / close pulse switch and the second pulse. A switch is a common element. The switching unit 6 includes a first switching switch provided in the middle of the path directly connecting the power source 5 and the load circuit 4, and a second switching provided in the middle of the path connecting the driving unit and the first pulse switch. The first pulse switch can also be expressed as a power supply device 1 that is connected in parallel with the power supply 5 and the load circuit 4 and is connected to the ground. Here, each of the first pulse switch, the open / close pulse switch, and the second pulse switch is a switch having an output by a pulse width, and corresponds to the elements of the first switch 7, the open / close switch 8, and the second switch 9, respectively. .

(Embodiment 2)
Next, a second embodiment will be described. In the second embodiment, a power supply device will be described using a more specific circuit as an example with reference to FIGS.

  9 to 13 are block diagrams of the power supply apparatus according to Embodiment 2 of the present invention. Each of FIG. 9 to FIG. 13 shows a circuit diagram having the same circuit configuration, and shows different operating states. The operation of the power supply device 50 can be explained by all of FIGS. 9 to 13.

  (1) FIG. 9 shows a state where the switching unit 56 has selected neither the first route 52 nor the second route 53. Circuit diagrams common to FIGS. 9 to 13 are shown.

  (2) FIG. 10 shows a state where the switching unit 56 selects the first path 52 and the power source 55 supplies power to the load circuit 54 via the first path. In particular, the first path 52 directly conducts the power supply 55 and the load circuit 54 and shows a period during which the power supply 55 supplies power to the load circuit 54.

  (3) FIG. 11 shows a state where the switching unit 56 selects the first path 52 and the power supply 55 supplies power to the load circuit 54 via the first path. However, unlike FIG. 10, the first switch 57 is short-circuited (ON), and the load circuit 54 is connected to the ground, indicating that the power supply period to the load circuit 54 is not being supplied. Yes.

  (4) FIG. 12 shows a state where the switching unit 56 selects the second path 53 and the power supply 55 supplies power to the load circuit 54 via the second path 53. In particular, the second path 53 directly conducts the power supply 55 and the load circuit 54 and indicates a period in which the power supply 55 supplies power to the load circuit 54.

  (5) FIG. 13 shows a state where the switching unit 56 selects the second path 53 and the power source 55 supplies power to the load circuit 54 via the second path 53. However, unlike FIG. 12, the second switch 59 is short-circuited (ON), and the load circuit 54 is connected to the ground, indicating that the power supply period to the load circuit 54 is not being supplied. Yes.

(Circuit overview)
First, an overall outline of the circuits shown in FIGS. 9 to 13 will be described.

  The power supply device 50 shown in FIGS. 9 to 13 may be regarded as a power supply device after removing the load circuit 54 or may be regarded as an electronic circuit including the load circuit 54. As described in the first embodiment, the load circuit 54 may be a processor that operates a software program such as a CPU or a DSP, or may be an electronic circuit or a semiconductor integrated circuit that performs specific arithmetic processing. Good.

  The power supply device 50 includes a first path 52 and a second path 53, and includes a power supply 55 that supplies power to the load circuit 54 via one of the first path 52 and the second path 53. ing. The power source 55 is a household power source as in the first embodiment, or may be a battery or a battery.

  The power supply device 50 further includes a switching unit 56 that switches between the first path 52 and the second path 53, a first switch 57 that controls the first power value supplied from the first path 52, and the first switch 57. And an opening / closing switch 58 (= second switch 59) for controlling the opening / closing timing of the second switch 59, and a second switch 59 for controlling the second power value supplied from the second path 53. Here, the open / close switch 58 and the second switch 59 are the same element and include a pair of MOS transistors SH and SL connected in series. The first switch 57 has a parallel connection relationship with the power supply 55 and the load circuit 54, and one of the first switches 57 is grounded. The circuit including the second switch 59 is the drive unit 60.

  The switching unit 56 includes a switch S1, a switch S2, and a switch S3. These switches are switched by the control signal 61, and the switching unit 56 selects the first path 52 and the second path 53.

  When the switching unit 56 selects the first path 52, the first path 52, which is a line passing outside the driving unit 58, conducts from the power supply 55 to the load circuit 54 as illustrated in FIG. 9. At this time, there is a line connected to the ground via the first switch 57 in the middle of the first path 52. When the first switch 57 is short-circuited (ON), the first path 52 and the ground are conducted, so that the load circuit 54 is conducted with the ground instead of the power supply 55. This state is a non-supply period in which power is not supplied to the load circuit 54. On the other hand, when the first switch 57 is open (OFF), the first path 52 directly conducts the power supply 55 and the load circuit 54, so that power is supplied to the load circuit 54 from the power supply 55. This state is a power supply period. The power value supplied to the load circuit 54 (the power value passing through the first path 52 and thus the first power value) is determined by the integrated value of the non-supply period and the supply period in a predetermined period.

  The first switch 57 has a MOS transistor SR, and a short circuit and an open circuit are determined by an input signal to the gate terminal of the MOS transistor SR. An input signal to the gate terminal is determined by the open / close switch 58. The open / close switch 58 includes a pair of MOS transistors SH and SL, and the MOS transistor SH and the MOS transistor SL operate symmetrically. That is, the control signal 57 via the switch SC2 is input to the gate terminals of the MOS transistor SH and the MOS transistor SL to control the operation of the MOS transistors SH and SL. For example, when the MOS transistor SH is short-circuited, the MOS transistor SL is open. Conversely, when the MOS transistor SH is open, the MOS transistor SL is short-circuited.

  By the operation of the pair of MOS transistors SH and SL, the gate terminal input of the MOS transistor SR constituting the first switch is controlled, and the short circuit and the open circuit of the MOS transistor SR are controlled. The short circuit and the open circuit of the MOS transistor SR determine whether the power supply 55 and the load circuit 54 are conductive or the ground and the load circuit 54 are conductive in the first path 52.

  On the other hand, when the switching unit 56 selects the second path 53, as shown in FIG. 9, the second path 53 connected to the load circuit 54 from the power supply 55 via the drive unit 60 is conducted. At this time, the second path 53 passes through the second switch 59. Since the second switch 59 is the same element as the open / close switch 58, the second switch 59 includes a pair of MOS transistors SH and SL. By short-circuiting and opening the pair of MOS transistors SH and SL, the second path 53 can be switched between the conduction between the power supply 55 and the load circuit 54 or the conduction between the ground and the load circuit 54. In the second path 53, only the second switch 59 switches between conducting and non-conducting in that path, so that the second power value supplied to the load circuit 54 by the second path 53 only by the operation of the second switch 59. Is determined. The second power value includes a supply period in which power is supplied from the power supply 55 to the load circuit 54 via the second path, and a non-supply period in which power is not supplied to the load circuit 54 because the second path 53 is connected to the ground. It is determined by the integral value of.

  Here, the pair of MOS transistors SH and SL are determined to be short-circuited and opened by contrasting operations as described above. Note that the MOS transistors SH and SL may be composed of a P-MOS transistor and an N-MOS transistor in order to perform a contrasting operation in the short circuit and the open circuit, and as shown in FIG. You may comprise so that the logic value of the signal input into a terminal may always become reverse. 9 to 13, an inverter is inserted in front of the gate terminal of the MOS transistor SL, and the logical values of the input signals to the gate terminals of the MOS transistor SH and the MOS transistor SL are reversed.

(Description of operation)
Next, operation | movement of the electric power supply apparatus 50 is demonstrated using FIGS.

(Power supply period in the first route shown in FIG. 10)
In FIG. 10, the switching unit 56 selects the first route 52. For this reason, the power supply 55 supplies power to the load circuit 54 via the first path 52. The control signal 61 short-circuits the terminal A and the output at the switches SC1, SC2, SC3 constituting the switching unit 56, and the gates of the pair of MOS transistors SH, SL constituting the open / close switch 58 via the switch SC2. Input to the terminal.

  The source terminal of the MOS transistor SH is connected to the power supply 55, and the source of the MOS transistor SL is connected to the ground. The drain terminal of the MOS transistor SH and the drain terminal of the MOS transistor SL are connected to each other, and the drain terminal outputs a signal to the gate terminal of the MOS transistor SR via the switch SC3.

  When the control signal 61 is input with a certain logical value, the MOS transistor SH is short-circuited and the MOS transistor SL is opened. In this case, the open / close switch 58 outputs a signal from the power supply 55 through the short-circuited MOS transistor SH. That is, the logical value of the signal output from the open / close switch 58 is Hi level. When the MOS transistor SR constituting the first switch 57 is a P-MOS transistor, the Hi level signal is input to the gate terminal of the MOS transistor SR, so that the MOS transistor SR is opened and the first path 52 and the ground are connected. Is not conductive. That is, as shown in FIG. 10, the first path 52 conducts directly from the power supply 55 to the load circuit 54. As a result, the power supply 55 supplies power to the load circuit 54 via the first path 52. This period is a power supply period.

  Note that the first switch 57 includes a MOS transistor SR having a large element size. Since the MOS transistor SR switches between power supply and non-supply, the switching loss and power consumption are large. However, it is necessary to increase the element size of the MOS transistor SR in terms of withstand voltage and the like.

  As described above, the control signal 61 controls the switching unit 56 and the open / close switch 58, so that the power supply 55 supplies power to the load circuit 54 via the first path 52.

  The control signal 61 may be output from an external control unit (not shown). The control unit has a software program in advance, and controls switching of the switching unit 56 and short-circuiting / opening of the open / close switch 58 according to the processing procedure of the software program.

  In addition, as described above, the power supply via the first path 52 is not only controlled by the first switch 57 (MOS transistor SR) being short-circuited to the ground by the first switch 57 (MOS transistor SR) but also the MOS transistor. It may be controlled by switching Sm.

  The MOS transistor Sm is located on the first path 52, and the MOS transistor SR is open during the period in which the MOS transistor Sm is short-circuited (that is, the first path 52 and the ground are not conducting). In the period, power is supplied from the power supply 55 to the load circuit 54. On the other hand, power is supplied from the power supply 55 to the load circuit 54 during the period in which the MOS transistor Sm is open and the MOS transistor SR is short-circuited (that is, in a state where the first path 52 and the ground are conductive). Not. That is, the MOS transistor Sm and the MOS transistor SR are alternately short-circuited and opened, whereby the power supply period from the power supply 55 to the load circuit 54 via the first path 52 and the non-supply period are repeated. The power value applied to the load circuit 54 is determined by the integrated value of the supply period and the non-supply period.

  Note that the short circuit and the open circuit of the MOS transistor Sm are switched by a switch 65 included in the drive unit 60. The switch 65 includes a pair of MOS transistors SH and SL, and the output of the pair of MOS transistors SH and SL is input to the gate terminal of the MOS transistor Sm, whereby the short circuit and the open circuit of the MOS transistor Sm are controlled. The switch 65 is controlled by a control signal 61 via the switch Sc1. When the logical value of the control signal 61 is a predetermined value, the MOS transistor SH of the switch 65 is short-circuited and a Hi level signal is input to the gate terminal of the MOS transistor Sm, and the logical value of the control signal 61 is opposite to the predetermined value. When the MOS transistor SL of the switch 65 is short-circuited, the Lo level signal is input to the gate terminal of the MOS transistor Sm. The MOS transistor Sm is switched between short circuit and open according to the logical value of the signal input to the gate terminal.

(Power non-supply period in the first route shown in FIG. 11)
In FIG. 11, the switching unit 56 selects the first path 52 as in FIG. The control signal 61 short-circuits the terminal A and the output at the switches SC1, SC2 and SC3 constituting the switching unit 56, and the gate terminals of the pair of MOS transistors SH and SL constituting the open / close switch 58 via the switch SC2. To enter.

  The source terminal of the MOS transistor SH is connected to the power supply 55, and the source of the MOS transistor SL is connected to the ground. The drain terminal of the MOS transistor SH and the drain terminal of the MOS transistor SL are connected to each other, and the drain terminal outputs a signal to the gate terminal of the MOS transistor SR via the switch SC3.

  Here, the control signal 61 outputs a signal having a logic value opposite to that in FIG.

  That is, when the control signal 61 is input to the gate terminals of the MOS transistor SH and the MOS transistor SL, the MOS transistor SH is opened and the MOS transistor SL is short-circuited. When the MOS transistor SL is short-circuited, a signal based on the ground voltage input to the source terminal of the MOS transistor SL is output to the drain terminal of the MOS transistor SL. That is, the open / close switch 58 outputs a Lo level signal. This Lo level signal is input to the gate terminal of the MOS transistor SR. Since the MOS transistor SR is a P-MOS transistor as described above, when the Lo level signal is input to the gate terminal, the MOS terminal SR is short-circuited, and the source terminal and the drain terminal are short-circuited. Since the source terminal of the MOS transistor SR is grounded, the middle portion of the first path 52 and the ground are connected, and the ground path 70 conducts.

  When the ground path 70 conducts in this way, the load circuit 54 is connected to the ground instead of the power supply 55, so that no power is supplied. A period in which this power is not supplied is a non-supply period. During this non-supply period, the load circuit 54 is disconnected from the power supply (of course, the power remaining in the capacitor etc. is discharged).

  In the predetermined period, the first switch 57 is finely switched between a short circuit and an open circuit. By this switching, a power supply period and a non-supply period as shown in FIGS. 10 and 11 occur. The first power value, which is the power supplied to the load circuit 54, is obtained as an integral value of this supply period and non-supply period in a predetermined period. This is the same as described with reference to FIG. If the power supply period within the predetermined period is long, as a result, the first power value supplied to the load circuit 54 becomes large.

  In this way, the control signal 61 controls the switching unit 56 and the open / close switch 58, whereby the supply of power through the first path 52 and the supplied power value are controlled.

  Further, as described in the power supply period in the first path 52, not only the power is conducted from the first switch 57 to the ground, but also the MOS transistor Sm on the first path 52 is opened and short-circuited (by the switch 65). The power non-supply period in the first path 52 may be controlled by switching).

(Power supply period in the second route shown in FIG. 12)
Next, the power supply period in the second route will be described with reference to FIG.

  In FIG. 12, the switching unit 56 selects the second path 53. For this reason, the power supply 55 supplies power to the load circuit 54 via the second path 53. The control signal 61 short-circuits the terminal B and the output at the switches SC1, SC2, and SC3 that constitute the switching unit 56, and is connected to the pair of MOS transistors SH and SL that constitute the second switch 59 via the switch SC2. Input to the gate terminal.

  The source terminal of the MOS transistor SH is connected to the power supply 55, and the source of the MOS transistor SL is connected to the ground. The drain terminal of the MOS transistor SH and the drain terminal of the MOS transistor SL are connected to each other, and this drain terminal outputs a signal to the B terminal of the switch SC3. The B terminal of the switch SC3 eventually outputs a signal to the load circuit 54.

  When the control signal 61 is input with a certain logical value, the MOS transistor SH is short-circuited and the MOS transistor SL is opened. In this case, the second switch 59 outputs a signal from the power supply 55 through the shorted MOS transistor SH. That is, the power from the power supply 55 is output to the load circuit 54 as it is via the second switch 59 in the middle of the second path 53. As shown in FIG. 12, the power supply 55 conducts through the second switch 59 to the load circuit 54. The power supply in the second path 53 is controlled only by opening / closing the second switch 59. When the MOS transistor SH is short-circuited and the second switch 59 is outputting a signal from the power supply 55, the load circuit 54 is in a power supply period.

  The second switch 59 includes MOS transistors SH and SL having small element sizes. When power is supplied through the second path 53, the second power value, which is low power, is supplied, so that the MOS transistors SH and SL do not require a large breakdown voltage. For this reason, the MOS transistors SH and SL are formed of small elements. Since the MOS transistors SH and SL are small elements, loss and power consumption are small in switching with these transistors. In particular, the MOS transistor SR, which is a large element, is not used for power supply via the second path 53, so that loss and power consumption can be reduced.

  In this way, when supplying a small power that is not a large power, a different path (second path 53) from a path that uses a large element is used, so that the loss in the power supply device 50 and the electronic circuit is reduced. And power consumption can be reduced. Furthermore, the second switch 59 that controls the power supply in the second path 53 is the same element as the open / close switch 58 that controls the first switch that controls the power supply in the first path 52 and is shared. Therefore, the circuit scale does not increase. Moreover, since the open / close switch 58 is a circuit realized as a drive unit 60 by a circuit board or a semiconductor integrated circuit, noise countermeasures are taken from the beginning. For this reason, even if the open / close switch 58 is used as the second switch 59, noise does not increase.

  As described above, the control signal 61 controls the switching unit 56 and the second switch 59, whereby the power supply 55 supplies power to the load circuit 54 via the second path 53.

  The control signal 61 may be output from an external control unit (not shown). The control unit has a software program in advance, and controls switching of the switching unit 56 and short-circuiting / opening of the second switch 59 according to the processing procedure of the software program.

(Power non-supply period in the second path shown in FIG. 13)
In FIG. 13, the switching unit 56 selects the second path 53 as in FIG. The control signal 61 short-circuits the terminal B and the output at the switches SC1, SC2, and SC3 that constitute the switching unit 56, and is connected to the pair of MOS transistors SH and SL that constitute the second switch 59 via the switch SC2. Input to the gate terminal.

  The source terminal of the MOS transistor SH is connected to the power supply 55, and the source terminal of the MOS transistor SL is connected to the ground. The drain terminal of the MOS transistor SH and the drain terminal of the MOS transistor SL are connected to each other, and this drain terminal outputs a signal to the B terminal of the switch SC3. The B terminal of the switch SC3 eventually outputs a signal to the load circuit 54.

  Here, the control signal 61 outputs a signal having a logical value opposite to that in FIG.

  That is, when the control signal 61 is input to the gate terminals of the MOS transistor SH and the MOS transistor SL, the MOS transistor SH is opened and the MOS transistor SL is short-circuited. When the MOS transistor SL is short-circuited, a signal based on the ground voltage input to the source terminal of the MOS transistor SL is output to the drain terminal of the MOS transistor SL. That is, the second switch 59 conducts the ground and the load circuit 54. As a result, the ground line 71 is conducted.

  When the ground path 71 conducts in this way, the load circuit 54 is connected to the ground instead of the power supply 55, so that no power is supplied. A period in which this power is not supplied is a non-supply period. During this non-supply period, the load circuit 54 is disconnected from the power supply (of course, the power remaining in the capacitor etc. is discharged).

  In the predetermined period, the second switch 59 is finely switched between a short circuit and an open circuit. By this switching, a power supply period and a non-supply period as shown in FIGS. 12 and 13 are generated. The second power value, which is the power supplied to the load circuit 54, is obtained as an integral value of this supply period and non-supply period in a predetermined period. This is the same as described with reference to FIG.

  In this way, the control signal 61 controls the switching unit 56 and the second switch 59, whereby the supply of power via the second path 53 and the supplied power value are controlled. Actually, the second power value is determined by the integral value of the power supply period shown in FIG. 12 and the power non-supply period shown in FIG. For example, if the power supply period is long, the second power value supplied to the load circuit 54 becomes large.

  As can be seen from the above, in order to supply the first power value via the first path 52, the power supply 55 and the load circuit 54 are electrically connected by the control of the switching unit 56, the open / close switch 58, and the first switch 57. And the case where the ground and the load circuit 54 are conductive.

  On the other hand, in order to supply the second power value via the second path 53, the power source 55 and the load circuit 54 are conducted by the control of only the switching unit 56 and the second switch 59 (= open / close switch 58). The case and the case where the ground and the load circuit 54 conduct are switched. For this reason, when supplying the 2nd electric power value which is small electric power, the electric power supply apparatus 50 has a mechanism in which extra switching loss and switching noise are hard to generate.

  As described above, the power supply device according to the second embodiment efficiently supplies each of the large power and the small power required by the load circuit without increasing the circuit scale, increasing the loss, and increasing the power consumption. it can.

  Note that the power supply device and the electronic circuit described in the first and second embodiments may be realized by a semiconductor integrated circuit.

(Embodiment 3)
Next, Embodiment 3 will be described.

  The power supply device and the electronic circuit described in Embodiments 1 and 2 may be used by being incorporated in an electronic device. In particular, in devices such as notebook personal computers, portable terminals, car navigation systems, PDAs, in-vehicle TVs, and mobile phones, power needs to be finely controlled in order to extend the usage time. For this reason, in such an electronic device, a case where a large amount of power is required and a case where a small amount of power is required occur depending on the operation content. When high power is required, the power supply device supplies power that is the first power value via the first path, and when low power is required, the power supply device passes through the second path. The electric power which is the 2nd electric power value is supplied via.

  Here, (1) The power supply device can separate and supply large power and power saving, so that the power consumption of the entire electronic device can be reduced. (2) Loss and power consumption are suppressed when supplying small power. Therefore, the power consumption of the power supply device can be reduced (since the second current value is controlled by switching of the second switch, which is a small element), so that the power consumption of the entire electronic device can be reduced. .

  As a result, there is a merit that the use efficiency of the battery in the electronic device is increased and the use time of the electronic device is extended.

  An example of an electronic device will be described.

  An example of the electronic device is illustrated in FIG. FIG. 14 is a perspective view of an electronic device according to Embodiment 3 of the present invention. The electronic device 82 is an electronic device that is required to be thin and small, such as a car TV or a personal monitor.

  The electronic device 82 includes a display 83, a light emitting element 84, and a speaker 85. The power supply devices 1 and 50 are stored in the electronic device 82, and an efficient power supply is realized. As a result, the electronic device 82 can realize low power consumption.

  As described above, by incorporating the power supply devices 1 and 50 described in the first and second embodiments into an electronic device, the performance of the electronic device can be improved and the usability is also improved. Of course, the power supply apparatuses 1 and 50 described in the first and second embodiments are also effectively used in stationary electronic devices at home and office. In such a stationary electronic device (desktop personal computer, television receiver, audio device, information processing device, etc.), the power supply devices 1 and 50 described in the first and second embodiments are used. Reduction of power consumption in electronic devices is realized.

  Note that the power supply devices and electronic devices described in the first to third embodiments are examples for explaining the gist of the present invention, and include modifications and alterations without departing from the gist of the present invention.

Block diagram of a power supply apparatus according to Embodiment 1 of the present invention Block diagram of a power supply apparatus according to Embodiment 1 of the present invention Time chart showing power supply by the first route in Embodiment 1 of the present invention Block diagram of a power supply apparatus according to Embodiment 1 of the present invention Time chart showing power supply by the second route Block diagram of a power supply apparatus according to Embodiment 1 of the present invention Block diagram of a power supply apparatus according to Embodiment 1 of the present invention Block diagram of a power supply apparatus according to Embodiment 1 of the present invention Block diagram of a power supply apparatus in Embodiment 2 of the present invention Block diagram of a power supply apparatus in Embodiment 2 of the present invention Block diagram of a power supply apparatus in Embodiment 2 of the present invention Block diagram of a power supply apparatus in Embodiment 2 of the present invention Block diagram of a power supply apparatus in Embodiment 2 of the present invention The perspective view of the electronic device in Embodiment 3 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power supply apparatus 2 1st path | route 3 2nd path | route 4 Load circuit 5 Power supply 6 Switching part 7 1st switch 8 Opening / closing switch 9 2nd switch 10 Drive part 11 Grounding

Claims (15)

A power supply for supplying power to the load circuit via any one of a first path and a second path different from the first path;
A switching unit for switching between the first route and the second route;
A first switch for controlling a supply period serving as a reference for the first power value supplied from the first path;
A drive unit including an open / close switch for controlling the opening / closing timing of the first switch;
A second switch for controlling a supply period serving as a reference for the second power value supplied from the second path,
The first power value is greater than the second power value;
The first path passes through the outside of the driving unit, and the second path passes through the inside of the driving unit,
The on-off switch and the second switch are power supply devices that are common elements. The first switch has a first pulse switch that switches between supply and stop of power according to time, and the second switch has a second pulse switch that switches between supply and stop of power according to time, and the first pulse The switch and the second pulse switch control the supply period by a pulse width;
The power supply device according to claim 1, wherein the first power value and the second power value are determined by the pulse width.   3. The power supply apparatus according to claim 2, wherein each of the first pulse switch and the second pulse switch includes a MOS transistor whose opening / closing is controlled by an input signal to a gate terminal.   4. The power supply apparatus according to claim 3, wherein the second pulse switch has a pair of MOS transistors connected in series. When the switching unit selects the first path, the output of the open / close switch becomes the gate input of a MOS transistor included in the first pulse switch to control the open / close period of the first pulse switch. The open / close period of the first pulse switch determines the supply period to determine the first power value;
The switching unit according to any one of claims 3 to 4, wherein when the switching unit selects the second path, an opening / closing period of the second pulse switch determines the supply period by determining the supply period. Power supply equipment.   6. The power supply device according to claim 1, further comprising a detection unit that detects which power value of the first power value and the second power value is required by the load circuit. .   The power supply device according to claim 6, wherein the detection unit detects which one of the first power value and the second power value is required based on an operation mode of the load circuit.   The power supply apparatus according to claim 1, further comprising a control unit that controls selection of a route from the first route and the second route in the switching unit.   The power supply apparatus according to claim 1, further comprising a switch control unit that controls a timing of opening and closing the second switch.   The power supply apparatus according to any one of claims 1 to 9, further comprising a filter that smoothes an input signal to the load circuit. A power supply for supplying power to the load circuit via any one of a first path and a second path different from the first path;
A switching unit for switching between the first route and the second route;
A first pulse switch for generating a pulse timing for determining a first power value supplied from the first path;
A drive unit including an open / close pulse switch for controlling the opening / closing timing of the first pulse switch;
A second pulse switch for generating a pulse timing for determining a second power value supplied from the second path,
The first power value is greater than the second power value;
The first path passes through the outside of the driving unit, and the second path passes through the inside of the driving unit,
The open / close pulse switch and the second pulse switch are common elements,
The switching unit is provided in the middle of a path connecting the power source and the load circuit, and in the middle of a path connecting the driving unit and the first pulse switch. A changeover switch,
The first pulse switch is a power supply device that is in parallel connection with the power supply and the load circuit and is grounded. The power supply device according to any one of claims 1 to 11,
An electronic circuit comprising a load circuit that is supplied with power from the power supply device and performs a predetermined operation.   The electronic circuit according to claim 12, wherein the load circuit is a central processing unit (hereinafter referred to as “CPU”) that performs an operation based on predetermined information. An electronic circuit according to any one of claims 12 to 13,
A control circuit for controlling the electronic circuit;
An electronic device comprising: a housing for storing the electronic circuit and the control circuit.   The electronic device according to claim 14, wherein the electronic device is any one of a notebook personal computer, a portable terminal, a car navigation system, and a PDA.

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