JP2009165218A - Power regeneration circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the reuse efficiency of an electric charge which is temporarily accumulated in a power regeneration circuit. <P>SOLUTION: The charging timing of an emission electric charge from a first circuit (a circuit for emitting an electric charge) 202 via a first switch circuit 203 to a secondary battery 201, and the discharging timing of a charging electric charge from the secondary battery 201 to a second circuit (a circuit needing an electric charge) 204 via a second switch circuit 205 are controlled by a drive circuit 206 by arranging the secondary battery 201 in place of an electric charge accumulation capacitor. The secondary battery 201 can send all the charging electric charges to the second circuit 204 different from the electric charge accumulation capacitor. For example, when an electromotive force of the secondary battery 201 is set to be a half of each power supply voltage Vcc of the first circuit 202 and the second circuit 204, and when a half of an electric charge of the first circuit 202 is charged to the secondary battery 201, the half of the electric charge is sent to the secondary circuit 204, and thus the reuse efficiency of the electric charge is enhanced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power that regenerates power by temporarily storing a part of charges from a circuit that discharges charges in a semiconductor integrated circuit (LSI) or the like and supplying the temporarily stored charges to a circuit that requires it. This relates to the regenerative circuit.

  Recently, reduction of power consumed by LSI itself is one of the most important issues, and devices that can operate with low power consumption are being actively studied. Among them, by regenerating part of the charge that was thrown away during the refresh operation of a DRAM (dynamic memory cell) that needs to be rewritten (refreshed) for holding data at regular intervals, There are attempts to reduce power consumption.

  For example, in Patent Document 1, instead of discharging all of the electric charge stored in the first drive signal line to the ground line during the refresh operation of the DRAM, a part of the electric charge is transferred to the second through the switch. A method of reducing the amount of charge supplied from the power source to the second drive signal line by regenerating the drive signal line is shown.

  Further, for example, in Patent Document 2, the charge stored in the first drive signal line is not directly regenerated to the second drive signal line, but is stored once in the capacitor and then stored in the capacitor. A method for regenerating the second drive signal line as necessary is shown. Also, the same type of regeneration method is shown in Patent Documents 3 and 4

  The regeneration method disclosed in Patent Document 2 does not necessarily require that the timing of charge emission and the timing of charge injection to the next stage be the same, and that the combination of drive signal lines for transferring charges can be arbitrarily selected. Therefore, the degree of freedom is higher than that of the regeneration method disclosed in Patent Document 1.

JP-A-3-295477 (Patent No. 3255947) JP-A-10-302466 JP 2006-172535 A JP 9-146490 A (Patent No. 3241777) JP 2004-281593 A (Patent No. 3989389)

  As described above, in the regeneration method disclosed in Patent Document 2, the charge emitted from one drive signal line is temporarily accumulated, and then reused when the drive signal line is charged next. It can be expected to reduce the total power consumption. However, since this regeneration method uses a capacitor as a charge storage device, there is a problem that it is difficult to increase the charge recycling efficiency.

  This problem will be described with reference to FIG. In this example, it is assumed that one capacitor is used for charge accumulation, and the charge of the first drive signal line is accumulated in a capacitor (storage capacitor) having the same capacity as the ground capacitance of the first drive signal line. Think.

  As shown in FIG. 4A, when the potential of the first drive signal line is Vcc and the storage capacitor is empty, the first drive signal line and the storage capacitor are electrically connected. As shown in FIG. 4B, 1/2 of the charge accumulated in the first drive signal line moves to the storage capacitor, and the ground potential becomes 1/2 Vcc.

  Next, when the first drive signal line and the storage capacitor are disconnected and the storage capacitor and the second drive signal line are connected, the ground potential becomes 1/4 Vcc as shown in FIG. ½ of the charge of the storage capacitor is used for charging the second drive signal line, and in all the steps, ¼ of the original charge of the first drive signal line is used for charging the second drive signal line. It was reused. In FIG. 4C, the charge remaining on the first drive signal line is discharged by connecting the first drive signal line to the ground line.

The charge recycling rate when a capacitor is used for charge storage is determined by the ratio of the signal line capacitance to the storage capacitor capacitance. If the storage capacitor capacity is k times the signal line capacity, the charge recycling rate η is η = k / (1 + k) ² . For this reason, it can be seen that the charge re-use rate when the capacitor is used for charge storage is maximum when k = 1 shown in FIG.

  Thus, when a capacitor is used for charge storage, even if a charge storage capacitor having an optimum capacity is used, only ¼ of the charge of the original first drive signal line is used as the second drive signal line. It is difficult to increase the charge recycling efficiency.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a power regeneration circuit capable of improving charge recycling efficiency and further reducing power consumption of an LSI or the like. There is to do.

  In order to achieve such an object, the present invention relates to a secondary battery, a first switch circuit provided between the secondary battery and the first circuit for discharging electric charge, A second switch circuit provided between the required second circuit, a charge timing to the secondary battery of the charge discharged from the first circuit via the first switch circuit, and a second switch circuit And a drive circuit for controlling the discharge timing of the charge charged from the secondary battery to the second circuit via the.

  According to the present invention, when the first circuit and the secondary battery are connected via the first switch circuit, the discharge electric charge from the first circuit is sent to the secondary battery, and the secondary battery is generated by the discharge electric charge. Is charged. Next, when the second circuit and the secondary battery are connected via the second switch circuit, the charge of the secondary battery is sent to the second circuit. In this case, unlike the charge storage capacitor, the secondary battery can send all of the charged charges to the second circuit. Thereby, for example, when the electromotive force of the secondary battery is set to 1/2 of the power supply voltage Vcc of the first circuit and the second circuit, the secondary battery is charged with 1/2 of the charge of the first circuit. This half charge is sent to the second circuit, and the charge recycling efficiency is increased.

  In the present invention, when the electromotive force of the secondary battery is ½ of the power supply voltage of the first circuit and the second circuit, the charge recycling efficiency can be maximized. Further, as an example of the present invention, the secondary battery may be a micro secondary battery formed on a semiconductor substrate. As an example of the present invention, the first circuit and the second circuit may be DRAMs or their drive signal lines. When the first circuit and the second circuit are DRAMs or their drive signal lines, the charging timing of the discharge from the first circuit to the secondary battery and the charge from the secondary battery to the second circuit The DRAM is refreshed by controlling the discharge timing.

  According to the present invention, a secondary battery is provided in place of the charge storage capacitor, and charging timing of the secondary battery discharged from the first circuit (circuit that discharges the charge) via the first switch circuit and Since the drive circuit controls the discharge timing of the charge from the secondary battery to the second circuit (the circuit that requires charge) via the two switch circuits, all of the charge of the secondary battery Is sent to the second circuit, the charge recycling efficiency can be increased, and the power consumption of the LSI or the like can be further reduced.

Hereinafter, the present invention will be described in detail with reference to the drawings.
〔Basic principle〕
FIG. 1 is a diagram for explaining the basic principle of a power regeneration circuit according to the present invention. In this example, one secondary battery is used for charge accumulation, and the electromotive force of the secondary battery (storage secondary battery) is the maximum ground voltage (power supply voltage) Vcc of the first and second drive signal lines. It is assumed that it is 1/2.

  As shown in FIG. 1A, in the state where the potential of the first drive signal line is Vcc and the storage secondary battery is empty, an electrical connection is established between the first drive signal line and the storage secondary battery. 1B, as shown in FIG. 1B, 1/2 of the charge accumulated in the first drive signal line is released to the storage secondary battery, and the storage secondary battery is charged by this released charge. It will be a thing.

  Next, when the first drive signal line and the storage secondary battery are disconnected and the storage secondary battery and the second drive signal line are connected, as shown in FIG. All of the charge of the battery is discharged to the second drive signal line, and the ground potential of the second drive signal line becomes 1/2 Vcc. Thereby, all of the charge of the storage secondary battery is used for charging the second drive signal line, and in all the steps, ½ of the original charge of the first drive signal line is used for the second drive signal line. It was reused for charging. In FIG. 1C, the charge remaining on the first drive signal line is discharged by connecting the first drive signal line to the ground line.

  The charge recycle rate when a secondary battery is used for charge storage is determined by the electromotive force of the secondary battery. In this case, the charge reuse rate η is maximized when the electromotive force of the secondary battery is ½ Vcc. That is, when the electromotive force of the secondary battery is m times the signal line voltage, the charge recycling rate η is η = 1−m when m ≧ 0.5, and η = m when m <0.5. Therefore, the electromotive force of the secondary battery is maximized when it is 1/2 Vcc.

  As described above, when a secondary battery is used for charge accumulation, assuming that the secondary battery has an electromotive force of ½ Vcc, ½ of the original charge of the first drive signal line is used as the second drive signal line. It will be possible to send. As a result, compared to the case where a capacitor is used for charge accumulation, the charge recycling efficiency is increased, and the power consumption of the LSI or the like can be further reduced.

  Further, it is particularly necessary to use a boosting means such as a charge pump in order to transfer the charge from the first drive signal line where the original charge has accumulated to the secondary battery to the second drive signal line. Instead, it is sufficient to simply connect the circuit with a switch or the like.

Embodiment
FIG. 2 is a diagram showing a main part of an embodiment of a power regeneration circuit according to the present invention based on the basic principle described above. In the figure, reference numeral 101 denotes a circuit for discharging electric charge (first circuit), and reference numeral 102 denotes a circuit that requires electric charge (second circuit). The circuit between the first circuit 101 and the second circuit 102 is shown in FIG. A power regeneration circuit 103 according to the present invention is connected between them.

  Inside the power regeneration circuit 103, there are provided a first switch circuit 104 and a second switch circuit 105 formed of transistors or the like, a secondary battery 106, and a drive circuit 107.

  The first switch circuit 104 includes a fixed contact 104a and movable contacts 104b to 104d, the fixed contact 104a is connected to the first circuit 101, the movable contact 104b is an open terminal, and the movable contact 104c is a secondary battery. Connected to the positive polarity side of 106, the movable contact 104d is grounded.

  The second switch circuit 105 includes a fixed contact 105a and movable contacts 105b to 105d, the fixed contact 105a is connected to the second circuit 102, the movable contact 105b is an open terminal, and the movable contact 105c is a secondary battery. The movable contact 105d is connected to the supply line of the power supply voltage Vcc.

  The drive circuit 107 has a connection state between the fixed contact 104a and the movable contacts 104b to 104d in the first switch circuit 104 and a connection state between the fixed contact 105a and the movable contacts 105b to 105d in the second switch circuit 105. It has a function to control. In an initial state, the drive circuit 107 connects the fixed contact 104a and the movable contact 104b in the first switch circuit 104, and connects the fixed contact 105a and the movable contact 105b in the second switch circuit 105. State.

  In the power regeneration circuit 103, the negative polarity side of the secondary battery 106 is grounded, and the electromotive force of the secondary battery 106 is ½ Vcc. The power supply voltage of the first circuit 101 and the second circuit 102 is Vcc.

  In this embodiment, the first circuit 101 and the second circuit 102 are DRAMs or their drive signal lines. In the power regeneration circuit 103, the secondary battery 106 is a micro secondary battery formed on a semiconductor substrate.

  Since the micro secondary battery is also described in, for example, Patent Document 5 and the like, detailed description thereof is omitted here. Patent Document 5 discloses, as an example of a micro secondary battery, a solid thin film secondary battery using a porous film formed on a part of the surface of a semiconductor element substrate by surface modification of the semiconductor element substrate itself as a negative electrode active material. It is shown. In this embodiment, such a micro secondary battery is used as the secondary battery 106.

[Charging the secondary battery (charging process)]
The drive circuit 107 connects the fixed contact 104a and the movable contact 104c of the switch circuit 104 when it is necessary to release the charge from the first circuit 101. Thereby, the fixed contact 104a is connected to the positive polarity side of the secondary battery 106 via the movable contact 104c, and the terminal potential of the first circuit 101 (the potential of the fixed contact 104a) is changed to the electromotive force (1 Charge transfer from the first circuit 101 to the secondary battery 106 until it is equal to / 2Vcc). That is, the charge discharged from the first circuit 101 flows into the secondary battery 106 via the switch circuit 104, and the secondary battery 106 is charged.

  Then, after the charging of the secondary battery 106 is completed, the drive circuit 107 connects the fixed contact 104a of the switch circuit 104 to the movable contact 104d as necessary, and the ground line of the charge left in the first circuit 101. Thereafter, the fixed contact 104a is connected to the movable contact 104b, and the connection state between the fixed contact 104a and the movable contacts 104b to 104d in the switch circuit 104 is returned to the initial state.

[Discharge from secondary battery (discharge process)]
The drive circuit 107 connects the fixed contact 105 a and the movable contact 105 c of the switch circuit 105 when it becomes necessary to supply electric charge to the second circuit 102. Thereby, the fixed contact 105a is connected to the positive polarity side of the secondary battery 106 via the movable contact 105c, and the terminal potential of the second circuit 102 (the potential of the fixed contact 105a) is changed to the electromotive force (1 Charge transfer from the secondary battery 106 to the second circuit 102 until equal to / 2Vcc). That is, the charge from the secondary battery 106 flows into the second circuit 102 via the switch circuit 105, and the secondary battery 106 is discharged.

  Then, after the discharge from the secondary battery 106 is completed, the drive circuit 107 connects the fixed contact 105a of the switch circuit 105 to the movable contact 105d as necessary, and the terminal potential of the second circuit 102 becomes the power supply voltage Vcc. The fixed contact 105a is connected to the movable contact 105b, and the connection state between the fixed contact 105a and the movable contacts 105b to 105d in the switch circuit 105 is returned to the initial state.

  When refreshing the DRAM, the drive circuit 107 repeats the charging process and the discharging process described above, thereby reusing part of the charge released from the first circuit 101 for charging the second circuit 102. . In this case, as described in the basic principle of the present invention described above, ½ of the original charge of the first circuit 101 can be sent to the second circuit 102, so that a capacitor is used for charge storage. Compared with the above, the charge recycling efficiency is increased.

  In the power regeneration circuit 103 shown in FIG. 2, a three-way type switch circuit having a fixed contact and three movable contacts is used as the switch circuits 104 and 105. However, such a three-way type is not necessarily used. The switch circuit 0 may not be used. In addition, although the secondary battery 106 is a micro secondary battery, it is not necessarily required to be a micro secondary battery.

  FIG. 3 shows a basic configuration of a power regeneration circuit according to the present invention. A power regeneration circuit 200 according to the present invention includes a secondary battery 201, a first switch circuit 203 provided between the secondary battery 201 and a circuit (first circuit) 202 that discharges electric charge, and a secondary battery. The second switch circuit 205 provided between the battery 201 and the circuit (second circuit) 204 that requires electric charge, and 2 of the discharge electric charge from the first circuit 202 via the first switch circuit 203 A drive circuit 206 that controls charging timing of the secondary battery 201 and discharging timing of charging charge from the secondary battery 201 to the second circuit 204 via the second switch circuit 205 is provided.

It is a figure explaining the basic principle of the electric power regeneration circuit which concerns on this invention. It is a figure which shows the principal part of one Embodiment of the electric power regeneration circuit which concerns on this invention. It is a figure which shows the basic composition of the electric power regeneration circuit which concerns on this invention. It is a figure explaining the problem at the time of using a capacitor for electric charge accumulation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... 1st circuit (circuit which discharges electric charge), 102 ... 2nd circuit (circuit which requires electric charge), 103 ... Power regeneration circuit, 104 ... 1st switch circuit, 105 ... 2nd switch circuit 106 ... secondary battery, 107 ... drive circuit, 200 ... power regeneration circuit, 201 ... secondary battery, 202 ... circuit for discharging electric charge (first circuit), 203 ... first switch circuit, 204 ... electric charge Necessary circuit (second circuit), 205... Second switch circuit, 206... Drive circuit.

Claims (5)

A secondary battery;
A first switch circuit provided between the secondary battery and a first circuit for discharging electric charge;
A second switch circuit provided between the secondary battery and a second circuit requiring electric charge;
Charge timing of the discharge from the first circuit via the first switch circuit to the secondary battery and charge from the secondary battery to the second circuit via the second switch circuit And a drive circuit for controlling the discharge timing of the power regeneration circuit. The power regeneration circuit according to claim 1,
The secondary battery has an electromotive force that is ½ of a power supply voltage of the first circuit and the second circuit. In the power regeneration circuit according to claim 1 or 2,
The secondary battery is a micro secondary battery created on a semiconductor substrate. An electric power regeneration circuit. In the electric power regeneration circuit described in any one of Claims 1-3,
The first circuit and the second circuit are dynamic memory cells or their drive signal lines. A power regeneration circuit. The power regeneration circuit according to claim 4,
The driving circuit controls the first dynamic type by controlling charging timing of the discharge charge from the first circuit to the secondary battery and discharging timing of the charge charge from the secondary battery to the second circuit. A power regeneration circuit characterized by refreshing a memory cell.

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