KR102036407B1 - Havesting circuit for realizing little ripple of an output voltage and method of controlling the same - Google Patents

Abstract

A harvesting circuit having a small ripple output voltage and a method of controlling the same are disclosed. The harvesting circuit includes an energy storage unit and a control unit for controlling the operation of the energy storage unit. Here, the control unit stores the energy to the energy storage unit more than the energy required at the output and provides the stored energy to the output.

Description

Harvesting circuit that realizes low output voltage ripple and how to control it {SAVESTING CIRCUIT FOR REALIZING LITTLE RIPPLE OF AN OUTPUT VOLTAGE AND METHOD OF CONTROLLING THE SAME}

The present invention relates to a harvesting circuit that realizes low ripple and a method of controlling the same.

The harvesting circuit is a circuit that generates a stable output voltage from the energy supplied from the harvester. Conventional harvesting circuits can cause large ripples in the output voltage. Let's look at this in detail.

1 is a view showing a conventional harvesting circuit, Figure 2 is a view showing the operating waveform when the energy provided from the harvester is less than the energy required for the output. 3 is a view showing an operating waveform when the energy provided from the harvester is larger than the energy required by the output, and FIG. 4 is a view showing an operating waveform for a situation in which two control methods are switched in a conventional harvesting circuit. FIG. 5 is a diagram illustrating an operation waveform at a threshold point at which a control method is switched in a conventional harvesting circuit.

1 to 5, two control methods are set according to the relationship between the harvester and the output power.

The control method includes a control method when the harvester power is lightly sourced than the power required at the output and a control method when the harvester power is heavily sourced than the power required at the output.

4 is a description of a reference for switching between two control methods in a conventional harvesting circuit. If the output voltage is 75mV lower than the reference voltage, the harvester operates in lightly sourced mode, deciding that the energy supplied by the harvester is insufficient. If the output voltage is higher than 75mV, the harvester operates in the heavily sourced mode.

Here, when the power supplied from the harvester and the power required by the output are similar, as shown in FIG. 5, the two control methods are repeatedly operated, and as a result, a ripple (150mV) of the output voltage increases. .

KR 10-1643817 B

The present invention provides a harvesting circuit having a small ripple output voltage and a method of controlling the harvesting circuit.

In order to achieve the above object, the harvesting circuit according to an embodiment of the present invention is an energy storage unit; And a control unit for controlling the operation of the energy storage unit. Here, the control unit stores the energy to the energy storage unit more than the energy required at the output and provides the stored energy to the output.

Harvesting circuit according to another embodiment of the present invention energy storage; A first switch for switching a connection between a harvester and one end of the energy storage unit; A second switch for switching a connection between the secondary energy store and one end of the energy store; And a control unit for controlling the operation of the switches. Here, when the energy stored from the harvester to the energy storage unit is less than the energy required at the output, the first switch is turned on and the second switch is off to store the energy of the harvester to the energy storage unit, A second switch is on and the first switch is off to store the energy of the secondary energy store into the energy store, and then the inductor provides the stored energy to the output under control of the controller.

Harvesting circuit control method according to an embodiment of the present invention comprises the steps of providing energy from the harvester to the energy storage; Providing energy from a secondary energy store to the energy store; And providing energy stored in the energy storage unit as an output when the energy provided by the harvester and the secondary energy storage unit is greater than the energy required at the output by the energy provided from the harvester and the secondary energy storage unit.

The harvesting circuit control method according to another embodiment of the present invention comprises the steps of providing energy from the harvester to the energy storage unit; Providing energy stored in the energy storage as an output; Blocking energy provided from the energy storage to the output when the voltage of the output reaches a preset voltage; And providing remaining energy of the energy storage unit to the secondary energy storage unit.

The harvesting circuit and the method for controlling the same according to the present invention always store energy above the energy required by the output in the inductor and then provide the stored energy as an output at once. As a result, even if the energy of the harvester and the energy required at the output are similar, the operation mode is not arbitrarily switched, and as a result, the ripple of the output voltage can be significantly reduced.

1 is a view showing a conventional harvesting circuit.
2 is a view showing an operating waveform when the energy provided from the harvester is smaller than the energy required by the output.
3 is a view showing an operating waveform when the energy provided from the harvester is greater than the energy required by the output.
FIG. 4 is a diagram illustrating an operating waveform for a situation in which two control methods are switched in a conventional harvesting circuit.
FIG. 5 is a diagram illustrating an operating waveform at a threshold point at which a control method is switched in a conventional harvesting circuit.
6 is a circuit diagram showing the structure of a harvesting circuit according to an embodiment of the present invention.
7 is a flowchart illustrating a process of controlling the harvesting circuit according to an embodiment of the present invention.
FIG. 8 is a timing diagram illustrating waveforms of signals when the power supplied by the harvester according to an embodiment of the present invention is larger than the power required at the output.
FIG. 9 is a timing diagram illustrating waveforms of signals when the power supplied by the harvester according to an embodiment of the present invention is smaller than the power required at the output.

As used herein, the singular forms "a", "an" and "the" include plural forms unless the context clearly indicates otherwise. In this specification, terms such as “consisting of” or “comprising” should not be construed as necessarily including all of the various components or steps described in the specification, and some of the components or some steps It should be construed that it may not be included or may further include additional components or steps. In addition, the terms "... unit", "module", etc. described in the specification mean a unit for processing at least one function or operation, which may be implemented in hardware or software or a combination of hardware and software. .

The present invention relates to a harvesting circuit (Harvesting circuit) and a method for controlling the same, it is possible to realize an output voltage having a small ripple.

According to one embodiment, the harvesting circuit and a method for controlling the same may be provided by the inductor to the output at once the energy required by the output. In this case, even if the energy of the harvester and the energy required at the output are similar, the operation mode is not switched arbitrarily, and as a result, the ripple of the output voltage can be significantly reduced.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

6 is a circuit diagram illustrating a structure of a harvesting circuit according to an embodiment of the present invention, and FIG. 7 is a flowchart illustrating a process of controlling the harvesting circuit according to an embodiment of the present invention. FIG. 8 is a timing diagram showing waveforms of signals when the power supplied by the harvester according to the embodiment of the present invention is larger than the power required at the output. FIG. 9 is a timing diagram showing the harvester according to the embodiment of the present invention. A timing diagram showing waveforms of signals when the power supplied is smaller than the power required at the output.

Referring to FIG. 6, the harvesting circuit of the present embodiment includes an energy storage unit 600, for example, an inductor L, a charge switching unit 600, an output switching unit 604, and a secondary energy storage unit 606. Battery), for example a secondary battery and a controller 606.

Hereinafter, for convenience of explanation, it is assumed that the energy storage unit 600 is an inductor L and the secondary energy storage unit 606 is a secondary battery.

The inductor 600 may receive and store energy primarily from a harvester (not shown), and may store and receive energy from a secondary battery 606 when necessary.

Inductor 600 also provides the stored energy to output C _OUT . In particular, the inductor 600 may have an output (C _OUT) under the control of the energy (electric power) and the output (C _OUT), the control unit 608 regardless of the relative size of the energy (power) required by the supplied from the harvester Energy can be provided to the output (C _OUT ) at once.

The charge switching unit 602 may include switches MP1, MP2, and MN1 associated with an operation of providing energy to the inductor 600. Here, the switches MP1, MP2 and MN1 are controlled by the control signals Φ _HAV , Φ _BAT1 , and Φ _N1 output from the control signal unit 616.

The switch MP1 switches a connection between the harvester and one end of the inductor 600 and may be, for example, a PMOS transistor.

The switch MN1 switches the connection between one end of the inductor 600 and the ground, and may be, for example, an NMOS transistor.

 The switch MP2 switches the connection between one end of the inductor 600 and the secondary battery 606 and may be, for example, a PMOS transistor.

The output switching unit 604 may include switches MP3, MP4, and MN2 related to an operation of outputting energy stored in the inductor 600. Here, the switches MP3, MP4 and MN2 are controlled by the control signals Φ _OUT , Φ _BAT2 , and Φ _N2 output from the control signal unit 616.

The switch MP3 switches a connection between the other end of the inductor 600 and the output C _OUT , and may be, for example, a PMOS transistor.

The switch MN2 switches a connection between the other end of the inductor 600 and the ground, and may be, for example, an NMOS transistor.

 The switch MP4 switches a connection between the other end of the inductor 600 and the secondary battery 606, and may be, for example, a PMOS transistor.

Meanwhile, the switches MP1, MP2, MP3, and MP4 may be implemented as NMOS transistors as necessary.

The control inductor 608 to provide an output (C _OUT) at a time the output (C _OUT), the energy required in charging the energy and the inductor, the output (C _OUT) of the inductor 600 is more than the energy required by the ( 600, the operations of the charge switching unit 602 and the output switching unit 604 may be controlled.

According to an embodiment, the controller 608 may include comparators 610 and 614, an integrator 612, and a control signal unit 616.

The first comparator 610 compares the voltage of the output node (hereinafter referred to as “output voltage V _OUT ”) with the preset voltage V _H , and outputs the comparison result to the control signal unit 616. Here, the preset voltage (V _H) is used for the the harvester energy to determine when to block the energy supply to the output (C _OUT), the output (C _OUT) from greater when the inductor 600 than the energy required by the Can be. For example, the preset voltage V _H may correspond to the maximum voltage of the voltage required at the output C _OUT .

The integrator 612, the resistor R _ERR , the capacitor C _ERR , and the second comparator 614 are components of the charge time determiner, and provide time for supplying energy from the secondary battery 606 to the inductor 600. Used to determine.

Specifically, when the energy of the harvester is smaller than the energy required at the output C _OUT , additional energy is supplied from the secondary battery 606 to the inductor 600. In this case, the charging time determiner determines the time for which energy is supplied from the secondary battery 606 to the inductor 600.

Integrator 612 receives output voltage V _OUT and reference voltage V _REF and outputs voltage V _ERR .

The second comparator 614 compares the output V _ERR of the integrator 612 with the ramp signal V _RAMP and provides a comparison result (for example, a PWM signal) to the control signal unit 616.

The control signal unit 616 controls control signals Φ _HAV , Φ _BAT1 , for controlling the switches MP1, MP2, and MN1 based on the output of the first comparator 610 and the output of the second comparator 614. The control signals Φ _OUT , Φ _BAT2 , and Φ _N2 for controlling Φ _N1 and the switches MP3, MP4 and MN2 may be output.

Hereinafter, a process of controlling the harvesting circuit of the present invention will be described.

Referring to FIG. 7, it is determined whether the energy to be supplied from the harvester is greater than or equal to the energy required at the output C _OUT (S700).

When the energy to be supplied from the harvester is greater than the energy required at the output C _OUT , energy is stored from the harvester to the inductor 600 (S702).

Subsequently, the inductor 600 provides the stored energy to the output C _OUT (S704).

Subsequently, an output when the energy required by a (C _OUT) supplied to the output (C _OUT), for example, when the output voltage (V _OUT) has reached the preset voltage, the inductor 600 is the remaining energy Stored in the secondary battery 606 (S706). That is, the remaining energy is stored in the secondary battery 606 and used later when necessary.

On the other hand, when the energy to be supplied from the harvester is smaller than the energy required at the output C _OUT , energy is stored from the harvester to the inductor 600 (S708).

However, in this case, since the energy supplied from the harvester cannot satisfy the energy required at the output C _OUT , additional energy is required.

According to an embodiment, the secondary battery 606 may supply additional energy to the inductor 600 (S710).

Subsequently, the inductor 600 provides energy stored as an output C _OUT (S712). At this time, the control method of the present invention first charges the inductor 600 through an additional energy supply, and then outputs the power C only when the energy stored in the inductor 600 becomes higher than the energy required by the output C _OUT . _OUT ) can provide energy at a time.

In this case, even if the energy of the inductor 600 and the energy required by the output C _OUT are similar, since the mode switching is not arbitrarily made, the ripple may hardly occur in the output voltage.

Hereinafter, a process of controlling the harvesting circuit will be described in detail with reference to FIGS. 6, 8, and 9.

First, the operation of the harvesting circuit will be described with reference to FIGS. 6 and 8 when the energy supplied by the harvester to the inductor 600 is greater than the energy required at the output C _OUT .

In this case, no additional energy supply is needed for the inductor 600. Thus, the switch MP2 located in the energy supply path from the secondary electricity 606 is always off. For example, the control signal Φ _BAT1 having high logic for the entire time is input to the gate of the switch MP2 which is a PMOS transistor. In addition, the charging time determiner may be inactive for the entire time.

At times t1 to t2, energy is supplied from the harvester to the inductor 600. For this purpose, the control signal Φ _HAV having a low logic is provided to the switch MP1 (for example, a PMOS transistor) so that the switch MP1 is turned on, and the control signal Φ _N2 having a high logic is the switch MN2. It is provided to switch MN2 is turned on.

At this time, the switch MN1 (e.g., an NMOS transistor), the switch MP3 (e.g., a PMOS transistor), and the control signal Φ _N1 having a low logic are turned off so that the switch MP4 (e.g., a PMOS transistor) is turned off. Input to the gate of MN1, control signals Φ _OUT and Φ _BAT2 having high logic are input to the gates of the switches MP3 and MP4.

On the other hand, the output voltage (V _OUT ) is reduced between the preset voltage (V _H ) and the reference voltage (V _REF ), if the output voltage (V _OUT ) is substantially equal to the reference voltage (V _REF ) output C ( _The operation of providing energy to _OUT ) is performed at t2 to t3 time.

At times t2 to t3, the energy of the inductor 600 is provided to the output C _OUT , with the result that the output voltage V _OUT rises. To this end, the control signal Φ _OUT having the low logic is input to the gate of the switch MP3 so that the switch MP3 is turned on, and the control signal Φ _N1 having the high logic is input to the gate of the switch MN1. Switch MN1 is turned on.

At this time, the control signal Φ _N2 having the low logic is input to the gate of the switch MN2 so that the switch MN2 is turned off, and the control signals Φ _HAV and Φ _BAT2 having the high logic are the switches MP1. And the switches MP1 and MP4 are turned off, respectively, through the gates of MP4. As a result, no energy is supplied to the inductor 600 from the harvester and the secondary battery 606.

Subsequently, when the output voltage V _OUT rises to reach the preset voltage V _H , the inductor 600 no longer provides energy to the output C _OUT and the inductor 600 at t3 to t4 time. Supplying the remaining energy to the secondary battery 606 is performed.

When the output voltage V _OUT rises to reach the preset voltage V _H , the first comparator 610 is opposite to the existing logic because the output voltage V _OUT and the preset voltage V _H have become the same. Output the logic In this case, the control signal unit 616 inputs the control signal Φ _OUT having the high logic to the gate of the switch MP3 to turn off the switch MP3. As a result, the energy supply from the inductor 600 to the output C _OUT is cut off.

At times t3 to t4, the control signal Φ _BAT2 having a low logic is input to the gate of the switch MP4 so that the remaining energy of the inductor 600 is provided to the secondary battery 606 so that the switch MP4 is turned on. The control signal Φ _N1 having a high logic is input to the gate of the switch MN1 so that the switch MN1 is turned on.

At this time, the control signals Φ _HAV and Φ _OUT having high logic are input to the gates of the switches MP1 and MP3 so that the switches MP1, MN2 and MP3 are turned off so that the switches MP1 and MP3 are turned off. ) is off and the control signal (Φ _N2) having a logic low input to the gate of the switch (MN2), the switch (MN2) is turned off.

Subsequently, the above operations are repeatedly performed.

Next, the operation of the harvesting circuit will be described with reference to FIGS. 6 and 9 when the energy supplied by the harvester to the inductor 600 is smaller than the energy required at the output C _OUT .

In this case, additional energy supply to the inductor 600 is required. Thus, the supply of energy from the secondary electricity 606 to the inductor 600 is essential. The energy supply from the secondary electricity 606 to the inductor 600 is determined by the charge time determiner.

At times t5 to t6, energy is supplied from the harvester to the inductor 600. For this purpose, the control signal Φ _HAV having a low logic is provided to the switch MP1 (for example, a PMOS transistor) so that the switch MP1 is turned on, and the control signal Φ _N2 having a high logic is the switch MN2. It is provided to switch MN2 is turned on.

At this time, the switch MN1 (e.g., an NMOS transistor), the switch MP3 (e.g., a PMOS transistor), and the control signal Φ _N1 having a low logic are turned off so that the switch MP4 (e.g., a PMOS transistor) is turned off. Input to the gate of MN1, control signals Φ _OUT and Φ _BAT2 having high logic are input to the gates of the switches MP3 and MP4.

On the other hand, the output voltage V _OUT decreases.

Subsequently, when all the energy of the harvester is discharged, the operation of supplying the energy of the secondary battery 606 to the inductor 600 is performed at t6 to t7 hours. At this time, the charging time determining unit has a comparison signal having information on the time to charge the energy corresponding to the difference between the energy to be charged in the inductor 600 and the current charged energy using the ramp signal (V _RAMP ) Outputs

At times t6 to t7, energy of the secondary battery 606 is supplied to the inductor 600. To this end, the control signal Φ _BAT1 having a low logic is input to the gate of the switch MP2 so that the switch MP2 is turned on, and the control signal Φ _N2 having a high logic is input to the gate of the switch MN2. The switch MN2 is turned on.

At this time, the control signals Φ _HAV , Φ _OUT and Φ _BAT2 having high logic are respectively input to the gates of the switches MP1, MP3 and MP4 so that the switches MP1, MP3 and MP4 are turned off, The control signal Φ _N1 having the low logic is input to the gate of the switch MN1 so that the switch MN1 is turned off.

At times t7 to t8, the energy of the inductor 600 is provided to the output C _OUT , with the result that the output voltage V _OUT rises. The energy of the inductor 600 is provided to the output C _OUT until all the energy required at the output C _OUT is satisfied. To this end, the control signal Φ _OUT having the low logic is input to the gate of the switch MP3 so that the switch MP3 is turned on, and the control signal Φ _N1 having the high logic is input to the gate of the switch MN1. Switch MN1 is turned on.

At this time, the control signal Φ _N2 having the low logic is input to the gate of the switch MN2 so that the switch MN2 is turned off, and the control signals Φ _HAV and Φ _BAT2 having the high logic are the switches MP1. And the switches MP1 and MP4 are turned off, respectively, through the gates of MP4.

Subsequently, the above operations are repeatedly performed.

In summary, when the energy of the harvester is greater than the energy supplied by the output C _OUT , the energy required by the output C _OUT in the inductor 600 is output (C _OUT ). The remaining energy stored in the secondary battery 606 is stored in the secondary battery 606, and when the energy of the harvester is smaller than the energy required by the output C _OUT , the energy of the harvester is reduced. The energy is additionally stored as the inductor 600 to make the energy of the inductor 600 more than the energy required by the output C _OUT , and then provides the energy of the inductor 600 to the output C _OUT at once.

That is, the harvesting circuit of the present invention always provides the energy of the inductor 600 to the output C _OUT after making the energy of the inductor 600 more than the energy required by the output C _OUT . As a result, even if the energy of the harvester and the energy required at the output C _OUT are similar, a phenomenon in which the operation mode is randomly switched does not occur, so that ripple may hardly occur at the output voltage V _OUT .

The embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention. Should be considered to be within the scope of the following claims.

600: energy storage unit 602: charge switching unit
604: output switching unit 606: secondary energy storage unit
608 control unit 610 first comparator
612: integrator 614: second comparator
616: control signal unit

Claims (14)

An energy storage unit;
A control unit controlling an operation of the energy storage unit;
A charge switching unit for switching a connection between a harvester or secondary energy storage unit and the energy storage unit; And
An output switching unit for switching the connection between the energy storage unit and the output unit or the secondary energy storage unit,
The control unit stores the energy to the energy storage unit more than the energy required by the output unit and provides the stored energy to the output unit,
The control unit stores energy from the secondary energy storage unit to the energy storage unit when energy stored in the energy storage unit from the harvester is smaller than the energy required by the output unit. And storing the energy in the energy storage unit and providing the stored energy to the output unit at once. delete The harvesting circuit of claim 1, wherein the energy storage unit is an inductor. The method of claim 3, wherein the charge switching unit,
A first switch for switching a connection between the harvester and one end of the energy storage unit;
A second switch for switching a connection between the secondary energy store and one end of the energy store; And
A third switch for switching a connection between one end of the energy storage and a ground;
The output switching unit,
A fourth switch for switching a connection between the other end of the energy storage and the output;
A fifth switch for switching a connection between the other end of the energy storage and the secondary energy storage; And
A sixth switch for switching the connection between the other end of the energy storage and the ground,
And the switches are controlled by control signals of the controller. The energy storage device of claim 4, wherein the energy stored from the harvester to the energy storage unit is greater than the energy required by the output unit.
The first switch and the sixth switch are turned on and the remaining switches are turned off so that energy of the harvester is stored in the energy storage unit,
The third switch and the fourth switch are turned on and the remaining switches are turned off to provide energy stored in the energy storage to the output unit,
And the third switch and the fifth switch are turned on and the remaining switches are turned off so that energy remaining in the energy storage unit is provided to the secondary energy storage unit. The method of claim 5, wherein the control unit,
A first comparator connected to a node of the output unit; And
Further comprising a control signal,
The first comparator senses whether the voltage of the output unit has reached a preset voltage, and the control signal unit outputs the corresponding control signal to turn off the fourth switch when it is detected that the voltage of the output unit has reached the preset voltage. And a fourth switch to block the energy provided from the energy storage unit to the output unit. The energy storage device of claim 4, wherein the energy stored from the harvester to the energy storage unit is smaller than the energy required by the output unit.
The first switch and the sixth switch are turned on and the remaining switches are turned off so that energy of the harvester is stored in the energy storage unit,
The second switch and the sixth switch are turned on and the remaining switches are turned off so that the energy of the secondary energy storage is stored in the energy storage so that the energy of the energy storage is greater than the energy required by the output,
And the third switch and the fourth switch are turned on and the remaining switches are turned off so that energy stored in the energy storage unit is provided to the output unit. The method of claim 7, wherein the control unit,
A charge time determiner; And
Further comprising a control signal,
And the charging time determiner determines a time at which energy is supplied from the secondary energy store to the energy store, and the control signal unit controls an operation of a corresponding switch according to the determined time. The method of claim 8, wherein the charging time determiner,
An integrator connected to the node of the output unit; And
A second comparator connected to an output terminal of the integrator,
Harvesting circuit, characterized in that the output of the second comparator is provided to the control signal. An energy storage unit;
A first switch for switching a connection between a harvester and one end of the energy storage unit;
A second switch for switching a connection between the secondary energy store and one end of the energy store; And
A control unit for controlling the operation of the switches,
When the energy stored from the harvester to the energy storage is less than the energy required at the output, the first switch is turned on and the second switch is turned off so that the energy of the harvester is stored in the energy storage, and the second A switch is turned on and the first switch is turned off so that energy of the secondary energy storage unit is stored in the energy storage unit, and then the energy storage unit provides the stored energy to the output under the control of the controller. Harvesting circuit. 11. The harvesting circuit according to claim 10, wherein energy is supplied from said secondary energy storage to said energy storage until it is above the energy required at said output. Providing energy from the harvester to the energy store;
Providing energy from a secondary energy store to the energy store; And
Providing energy stored in the energy storage unit as an output when energy from the energy storage unit becomes more than the energy required at the output by energy provided from the harvester and the secondary energy storage unit; And
Determining a time for providing energy from the secondary energy store to the energy store,
And energy is provided from the secondary energy storage to the energy storage for the determined time.
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