Switched capacitor conversion circuit and switching conversion unit therein

Abstract

A switched capacitor conversion circuit and a switching conversion unit therein. The switched capacitor conversion circuit includes a plurality of capacitors and a plurality of switches, wherein the plurality of switches are used to periodically switch the plurality of capacitors based on a switching cycle. During a first period, the plurality of switches control the first capacitor to be electrically connected between a first power source and a second power source, and control the second capacitor and a third capacitor to be connected in series and electrically connected between the second power source and a ground potential. During a second period, the plurality of switches control the first capacitor and the second capacitor to be connected in series and electrically connected between the second power source and the ground potential, and control the third capacitor to be connected in parallel and electrically connected to the second power source. This results in a ratio of a second current of the second power source to a first current of the first power source being 4.

Description

Technical Field

[0001] The present invention relates to a switched capacitance conversion circuit, and more particularly to a switched capacitance conversion circuit capable of selecting different conversion rates. The present invention also relates to a switching conversion unit for the switched capacitance conversion circuit. Background Art

[0002] Figure 1 A conventional charging system 1000 is shown, in which an N-fold switched capacitor converter 100 is used to convert between a first power source (corresponding to a first voltage V1 and a first current I1) and a second power source (corresponding to a second voltage V2 and a second current I2) by switching at least one capacitor (such as capacitor CFLY). The N-fold switched capacitor converter 100 can set a multiple N between the first voltage V1 and the second voltage V2. N is, for example, the ratio of the first voltage V1 to the second voltage V2, and is also the ratio of the second current I2 to the first current I1, and can be set to 2 times or 4 times.

[0003] like Figure 1 As shown, in a typical application, the N-fold switched capacitor converter 100 is used as a charging circuit, for example, to convert a first power source provided by an adapter 30 that complies with the USB Type C specification into a second power source to charge the battery 20. Figure 2 The path of the first current I1 provided by the adapter 30 has many parasitic resistances, such as the parasitic resistances (Rcn, Rwr) of the connector and connection lines, or the on-resistance of the load switch. Therefore, the higher the first current I1, the greater the energy loss caused by the parasitic resistance. On the other hand, if the ratio N of the second current I2 to the first current I1 is increased, the lower first current I1 can be converted into the same second current I2 (corresponding to the charging current), thereby effectively reducing the energy loss caused by the parasitic resistance.

[0004] Figure 3 A conventional switched capacitor converter 300 is shown, which is configured with two switching conversion units 131 and 132 coupled in a front-to-rear manner. The switching units 131 and 132 each have a current conversion ratio of 2, for example. That is, the output current I12 of the switching conversion unit 131 is twice the first current I1, and the output current of the switching conversion unit 132 (corresponding to the second current I2) is twice the output current I12 of the switching conversion unit 131.

[0005] Figure 3A disadvantage of the conventional switched capacitor converter 300 is that, due to the high voltage conversion ratio, all switches Q21-Q28 in the switching conversion unit 131 must be high-voltage resistant. From another perspective, the high-voltage resistant switches in switching conversion units 131 and 132 account for half of the total number of switches (Q21-Q28, Q31-Q38), preventing cost reduction.

[0006] The present invention addresses the deficiencies of the above-mentioned prior art and proposes a new switched capacitor conversion circuit that can support multiple current and voltage conversion multiples and requires only a small number of high-voltage resistant switches, thereby effectively reducing costs and circuit size. Summary of the Invention

[0007] In one aspect, the present invention provides a switched capacitor conversion circuit for converting a first power source into a second power source or converting the second power source into the first power source, the switched capacitor conversion circuit comprising: at least one switching conversion unit; and a control circuit for controlling the switching conversion unit; the switching conversion unit comprising: a plurality of capacitors, including a first capacitor, a second capacitor, and a third capacitor; and a plurality of switches for periodically switching the plurality of capacitors based on a switching cycle; wherein in a 4x conversion mode, in a first period of the switching cycle, the plurality of switches control the two ends of the first capacitor to be electrically connected to the first power source and the second power source, respectively, and control the first period of the switching cycle to be electrically connected to the second power source, respectively. The second capacitor and the third capacitor are connected in series and electrically connected between the second power supply and a ground potential; wherein, during a second period of the switching cycle, the multiple switches control the two ends of the first capacitor to be electrically connected to the first node and the ground potential, respectively, and the two ends of the second capacitor to be electrically connected to the first node and the second power supply, respectively, and control the third capacitor to be electrically connected in parallel with the second power supply; thereby periodically operating to perform power conversion between the first power supply and the second power supply, so that in the 4x conversion mode, the ratio of a first voltage of the first power supply to a second voltage of the second power supply is 4, and the ratio of a second current of the second power supply to a first current of the first power supply is 4.

[0008] In another aspect, the present invention provides a switching conversion unit for converting a first power source into a second power source or converting the second power source into the first power source, the switching conversion unit comprising: a plurality of capacitors, including a first capacitor, a second capacitor, and a third capacitor; and a plurality of switches for periodically switching the plurality of capacitors based on a switching cycle; wherein in a 4x conversion mode, in a first period of the switching cycle, the plurality of switches control the two ends of the first capacitor to be electrically connected to the first power source and the second power source, respectively, and control the second capacitor and the third capacitor to be electrically connected in series to the second power source. between a source and a ground potential; wherein in a second time period of the switching cycle, the multiple switches control the two ends of the first capacitor to be electrically connected to the first node and the ground potential, respectively, the two ends of the second capacitor to be electrically connected to the first node and the second power supply, respectively, and control the third capacitor to be electrically connected in parallel with the second power supply; thereby periodically operating to perform power conversion between the first power supply and the second power supply, so that in the 4x conversion mode, a ratio of a first voltage of the first power supply to a second voltage of the second power supply is 4, and a ratio of a second current of the second power supply to a first current of the first power supply is 4.

[0009] In one embodiment, in the 4x conversion mode, in a steady state, the ratio of the voltage across the first capacitor, the voltage across the second capacitor, and the voltage across the third capacitor is 3:2:1.

[0010] In one embodiment, the plurality of switches include first to eighth switches, wherein the first switch, the second switch, the third switch, and the fourth switch are sequentially coupled in series between the first power supply and the second power supply, and are sequentially coupled in pairs to a first node, a second node, and a third node. The fifth switch and the sixth switch are serially connected between the second power supply and the ground potential and are coupled to each other at a fourth node. The seventh switch and the eighth switch are serially connected between the second power supply and the ground potential and are coupled to each other at a fifth node. The first capacitor is coupled between the first node and the fourth node, the second capacitor is coupled between the second node and the fifth node, and the third capacitor is coupled between the third node and the fourth node. In the 4x conversion mode, in the During a first time period, the first, third, fifth, and eighth switches are conductive, and the second, fourth, sixth, and seventh switches are non-conductive, so as to control the first capacitor to be electrically connected between the first power source and the second power source, and to control the second capacitor and the third capacitor to be electrically connected in series between the second power source and the ground potential. During a second time period, each of the first to eighth switches operates in a state opposite to that of the first time period, so as to control the first capacitor and the second capacitor to be electrically connected in series between the second power source and the ground potential, and to control the third capacitor to be electrically connected in parallel with the second power source. Thus, power conversion between the first and second power sources is performed through periodic operation.

[0011] In one embodiment, in a 2x conversion mode, the second switch and the third switch are constantly turned on. In the 2x conversion mode, during a first period of the switching cycle, the first switch, the fifth switch, and the seventh switch are turned on, and the fourth switch, the sixth switch, and the eighth switch are turned off, so as to control the first capacitor, the second capacitor, and the third capacitor to be connected in parallel and electrically connected between the first power source and the second power source. During a second period of the switching cycle, the first switch and each of the fourth to eighth switches operate in a state opposite to that of the first period, so as to control the first capacitor, the second capacitor, and the third capacitor to be connected in parallel and electrically connected between the second power source and the ground potential. Such periodic operation results in a ratio of the first voltage to the second voltage being 2, and a ratio of a second current of the second power source to a first current of the first power source being 2.

[0012] In one embodiment, in a 3x conversion mode, during a first period of the switching cycle, the first, second, fourth, sixth, and seventh switches are conductive, and the third, fifth, and eighth switches are non-conductive, such that the terminals of the first capacitor are electrically connected to the first power source and the ground potential, the terminals of the second capacitor are electrically connected to the first power source and the second power source, and the terminals of the third capacitor are electrically connected to the second power source and the ground potential, respectively. During a second period of the switching cycle, each of the first to eighth switches operates in a state opposite to that of the first period, such that the first terminal of the first capacitor is floating, the second terminal of the first capacitor is electrically connected to the second power source, and the second and third capacitors are connected in series between the second power source and the ground potential. As a result of these periodic operations, a ratio of the first voltage to the second voltage is 3, and a ratio of a second current of the second power source to a first current of the first power source is 3.

[0013] In one embodiment, the first switch includes a first transistor and a second transistor connected in series, wherein a body diode of the first transistor and a body diode of the second transistor are in opposite directions.

[0014] In one embodiment, in a bypass mode, the first to fourth switches are turned on, and the fifth to eighth switches are turned off, so that the first power source and the second power source are directly electrically connected to each other.

[0015] In one embodiment, the at least one switching conversion unit includes a first switching conversion unit and a second switching conversion unit, which are connected in parallel between the first power source and the second power source. The first switching conversion unit and the second switching conversion unit switch the corresponding multiple switches in an interlaced phase manner to perform power conversion between the first power source and the second power source.

[0016] In one embodiment, the multiple switches in the first portion have a first withstand voltage and withstand a first peak voltage during a power conversion operation, and the multiple switches in the second portion have a second withstand voltage and withstand a second peak voltage during a power conversion operation, wherein the first peak voltage is twice the second peak voltage.

[0017] In one embodiment, the number of the switches in the first portion is less than 1 / 2 of the total number of the switches, and the number of the switches in the second portion is more than 1 / 2 of the total number of the switches.

[0018] In one embodiment, in the quadruple conversion mode, the plurality of switches in the first portion include the second switch and the third switch, and the plurality of switches in the second portion include the first switch and fourth to eighth switches.

[0019] In one embodiment, the first peak voltage, the second peak voltage, the first withstand voltage, and the second withstand voltage have the following relationship: first withstand voltage > first peak voltage > second withstand voltage > second peak voltage.

[0020] The following detailed description through specific embodiments will make it easier to understand the purpose, technical content, characteristics and effects achieved by the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A circuit block diagram of a conventional charging system and an N-fold switched capacitor converter therein is shown.

[0022] Figure 2 Display corresponds to Figure 1 Efficiency characteristic curve.

[0023] Figure 3 A circuit diagram showing a conventional N-fold switched capacitor converter is shown.

[0024] Figure 4 A circuit block diagram of the switched capacitor converter circuit of the present invention is shown.

[0025] Figure 5A and Figure 5B A schematic diagram showing a specific embodiment of a switching conversion unit and its operation in a switched capacitor conversion circuit according to the present invention is shown.

[0026] Figure 6 This diagram shows an operating waveform diagram of a switched capacitor converter circuit according to an embodiment of the present invention.

[0027] Figure 7A and Figure 7B A schematic diagram showing a specific embodiment of a switching conversion unit and its operation in a switched capacitor conversion circuit according to the present invention is shown.

[0028] Figure 8 This diagram shows an operating waveform diagram of a switched capacitor converter circuit according to an embodiment of the present invention.

[0029] Figure 9A and Figure 9B A schematic diagram showing a specific embodiment of a switching conversion unit and its operation in a switched capacitor conversion circuit according to the present invention is shown.

[0030] Figure 10 This diagram shows an operating waveform diagram of a switched capacitor converter circuit according to an embodiment of the present invention.

[0031] Figure 11 A schematic diagram showing a specific embodiment of a switching conversion unit and its operation in a switched capacitor conversion circuit according to the present invention is shown.

[0032] Figure 12 A circuit block diagram showing an embodiment of a switched capacitor converter circuit of the present invention is shown.

[0033] Explanation of symbols in the figure

[0034] 100: N-fold switched capacitor converter

[0035] 1100: Switch conversion unit

[0036] 1211, 1212: Switch conversion unit

[0037] 131, 132: Switch conversion unit

[0038] 14, 150, 170, 190: Switch conversion unit

[0039] 20: Battery

[0040] 200: Charging system

[0041] 300, 400: Switched capacitor converter

[0042] 50: Control circuit

[0043] BST: Bootstrap voltage

[0044] C1, C2, C3: capacitors

[0045] CB1: capacitor

[0046] CFLY: Capacitor

[0047] Co: Capacitor

[0048] Da, Db: body diode

[0049] DBT: diode

[0050] dQ11~dQ18: control signal

[0051] I1: first current

[0052] I12: output current

[0053] I2: Second current

[0054] N1 to N5: nodes

[0055] PH1: First period

[0056] PH2: Second period

[0057] Q0: switch

[0058] Q11~Q18: switch

[0059] Q11a, Q11b: transistors

[0060] Rcn, Rwr: parasitic resistance

[0061] Ts: switching period

[0062] V1: first voltage

[0063] V2: second voltage

[0064] VBUS: bus power

[0065] VC1, VC2, VC3: cross-voltage DETAILED DESCRIPTION

[0066] The drawings in the present invention are schematic diagrams, mainly intended to illustrate the coupling relationship between various circuits and the relationship between various signal waveforms. The circuits, signal waveforms and frequencies are not drawn according to scale.

[0067] Figure 4 A circuit block diagram of a switched capacitor converter circuit of the present invention is shown. In one embodiment, the switched capacitor converter circuit 400 is used to convert a first power source (corresponding to a first voltage V1 and a first current I1) into a second power source (corresponding to a second voltage V2 and a second current I2) or to convert the second power source into the first power source. The switched capacitor converter circuit 400 includes at least one switching conversion unit (such as Figure 4 The switching conversion unit 14 and the control circuit 50 are shown. The switching conversion unit 14 includes a plurality of capacitors (e.g., C1-Cm, where m is an integer greater than or equal to 2) and a plurality of switches (e.g., S1-Sk, where k is an integer greater than or equal to 2). The plurality of switches are configured to periodically switch the plurality of capacitors based on a switching period Ts to perform capacitive power conversion between the first power source and the second power source. The control circuit 50 is configured to control the switching conversion unit 14.

[0068] In one embodiment, the first power source is provided by, for example, an adapter compliant with the USB Type-C specification, and the second power source is used to charge a battery. In one embodiment, both the first current I1 and the second current I2 are constant currents, with the second current I2 being N times the first current I1, where N is a natural number greater than or equal to 1. When the adapter provides a constant first current I1, generating a constant second current for battery charging, the level of the first voltage V1 is determined by the second voltage V2 (corresponding to the battery voltage). Specifically, the first voltage V1 is N times the second voltage V2. During charging, since the battery voltage varies with the charging process, both the first voltage V1 and the second voltage V2 also vary with the charging process.

[0069] In another embodiment, the first voltage V1 and the second voltage V2 are both constant voltages, and the first voltage V1 is N times the second voltage V2.

[0070] In other embodiments, the second voltage V2 corresponds to a battery voltage provided by a battery, for example. The switching conversion unit 14 can convert the battery voltage into a first power source to power an external load. This operation corresponds to a USB OTG (On The Go) operation, for example.

[0071] Figure 5A and Figure 5B A schematic diagram showing a specific embodiment of a switching conversion unit and its operation in a switched capacitor conversion circuit according to the present invention is shown.

[0072] In one embodiment, the switching conversion unit 150 includes a capacitor C1 (corresponding to a first capacitor), a capacitor C2 (corresponding to a second capacitor), and a capacitor C3 (corresponding to a third capacitor). In this embodiment, the plurality of switches are used to periodically switch the capacitors C1, C2, and C3 based on a switching period Ts.

[0073] In one embodiment, the switching conversion unit of the present invention (such as the switching conversion unit 150) can operate in a 4x, 3x, 2x or 1x conversion mode. In one embodiment, in the 4x conversion mode, in the first period PH1 of the switching cycle Ts, as shown in FIG. Figure 5A As shown by the dotted line path, multiple switch control capacitors C1 are electrically connected between the first power supply and the second power supply, and the control capacitors C2 and capacitors C3 are connected in series and electrically connected between the second power supply and the ground potential. Specifically, as shown in FIG. Figure 5A As shown, the positive and negative terminals of the capacitor C2 and the capacitor C3 are reversely coupled.

[0074] In the second period PH2 of the switching cycle Ts, as Figure 5B As shown by the dotted line path, multiple switch control capacitors C1 and capacitors C2 are connected in series and electrically connected between the second power supply and the ground potential, and the control capacitor C3 is electrically connected in parallel with the second power supply. Specifically, as shown in FIG. Figure 5B As shown, the positive and negative terminals of capacitors C1 and C2 are reversely coupled. The power conversion between the first power source and the second power source is performed by the cyclic operation based on the switching period Ts described above. In the 4x conversion mode, the ratio of the first voltage V1 to the second voltage V2 is 4. Simultaneously, the ratio of the second current I2 to the first current I1 is also 4. In this high-multiplication mode, the first current I1 (e.g., provided by the aforementioned adapter) can be effectively reduced while maintaining the same second current I2 demand.

[0075] Continue reading Figure 5A and Figure 5BIn one embodiment, the plurality of switches include switches Q11 to Q18, wherein switch Q11, switch Q12, switch Q13, and switch Q14 are sequentially coupled in series between a first power source and a second power source, with switch Q11 and switch Q12 coupled to a node N1, switch Q12 and switch Q13 coupled to a node N2, and switch Q13 and switch Q14 coupled to a node N3. Switches Q15 and Q16 are connected in series between the second power source and a ground potential and coupled to each other at a node N4. Switches Q17 and Q18 are connected in series between the second power source and a ground potential and coupled to each other at a node N5. Capacitor C1 is coupled between node N1 and node N4, capacitor C2 is coupled between node N2 and node N5, and capacitor C3 is coupled between node N3 and node N4.

[0076] In one embodiment, the control circuit 50 is configured to generate control signals dQ11 - dQ18 for controlling the switches Q11 - Q18 , respectively.

[0077] The specific operation in the 4x conversion mode is as follows: In the first period PH1 ( Figure 5A ), switches Q11, Q13, Q15, and Q18 are conductive (black switches indicate conductive state, similarly hereinafter), and switches Q12, Q14, Q16, and Q17 are non-conductive (gray switches indicate non-conductive state, similarly hereinafter). This controls capacitor C1 to be electrically connected between the first power supply and the second power supply, and controls capacitor C2 and capacitor C3 to be connected in series and electrically connected between the second power supply and ground. Specifically, in this embodiment, during the first period PH1, the voltage across capacitor C2 VC2 is in phase with the second voltage V2, while the voltage across capacitor C3 VC3 is in antiphase with the second voltage V2.

[0078] In the second period PH2( Figure 5B ), each of switches Q11-Q18 operates in a state opposite to that of the first period PH1. That is, switches Q11, Q13, Q15, and Q18 are non-conductive, and switches Q12, Q14, Q16, and Q17 are conductive, thereby controlling capacitors C1 and C2 to be connected in series and electrically connected between the second power supply and the ground potential, and controlling capacitor C3 to be connected in parallel with the second power supply. It is noteworthy that in this embodiment, during the second period PH2, the voltage across capacitor C1 (VC1) is in phase with the second voltage V2, the voltage across capacitor C2 (VC2) is in phase with the second voltage V2, and the voltage across capacitor C3 (VC3) is in phase with the second voltage V2.

[0079] Figure 6 Display corresponds to Figure 5A and Figure 5B Operation waveform diagram of a specific embodiment of the switched capacitor converter circuit.

[0080] like Figure 6 As shown, in this embodiment, in the 4x conversion mode, in the steady state, the ratio of the first voltage V1 to the second voltage V2 is 4 times, as shown in FIG. Figure 6 In this example, the first voltage V1 is 20V, the second voltage V2 is 5V, and the ratio of the second current I2 to the first current I1 is also 4 times, as shown in FIG. Figure 6 In this example, the second current I2 is 8A, and the first current I1 is 2A.

[0081] On the other hand, in this embodiment, the ratio of the voltage across VC1 of the capacitor C1, the voltage across VC2 of the capacitor C2, and the voltage across VC3 of the capacitor C3 is 3:2:1. Specifically, the voltage across VC1 of the capacitor C1, the voltage across VC2 of the capacitor C2, and the voltage across VC3 of the capacitor C3 are 3*V2, 2*V2, and V2, respectively (for example, but not limited to, corresponding to FIG. 5 and FIG. Figure 6 15V, 10V, 5V in the .

[0082] It should be noted that the voltage across capacitor C1, VC1, corresponds to Figure 6 The voltage difference between the node N1 and the node N4 in the capacitor C2 corresponds to the voltage VC2 Figure 6 The voltage difference between the node N2 and the node N5 in the capacitor C3 corresponds to the voltage VC3 Figure 6 The voltage difference between node N3 and node N4 in .

[0083] Please continue reading Figure 5A and Figure 5B In one embodiment, the switching conversion unit 150 further includes a switch Q0 for controlling whether the bus power VBUS, for example, from the aforementioned adapter, is electrically connected to the first power source, thereby determining whether to initiate the aforementioned power conversion. Furthermore, in one embodiment, the switching conversion unit 150 further includes a capacitor CB1 and a diode DBT for forming a bootstrap circuit from the first power source to provide a bootstrap voltage BST for supplying to a driver circuit for driving the plurality of switches. Furthermore, when the second power source serves as the output power source, in one embodiment, the capacitor Co can serve as an output capacitor.

[0084] Figure 7A and Figure 7B A schematic diagram showing a specific embodiment of a switching conversion unit and its operation in a switched capacitor conversion circuit according to the present invention is shown. Figure 7A and Figure 7B The switching conversion unit 170 has the same hardware configuration as the switching conversion unit 150 , except that the switching conversion unit 170 operates in a 2x conversion mode.

[0085] like Figure 7A and Figure 7BAs shown, in the 2x conversion mode, switches Q12 and Q13 are constantly on. In this embodiment, in the 2x conversion mode, during the first period PH1 of the switching cycle Ts, switches Q11, Q15, and Q17 are turned on, and switches Q14, Q16, and Q18 are turned off, thereby controlling capacitors C1, C2, and C3 to be connected in parallel and electrically connected between the first power source and the second power source.

[0086] During the second period PH2 of the switching cycle Ts, the switch Q11 and each of the switches Q14-Q18 operate in a state opposite to that of the first period PH1. That is, the switches Q11, Q15, and Q17 are non-conducting, and the switches Q14, Q16, and Q18 are conductive, thereby controlling the capacitors C1, C2, and C3 to be connected in parallel and electrically connected between the second power supply and the ground potential.

[0087] Figure 8 Display corresponds to Figure 7A and Figure 7B FIG. 1 is an operational waveform diagram of an embodiment of a switched capacitor converter circuit.

[0088] like Figure 8 As shown, in this embodiment, in the 2x conversion mode, in the steady state, the ratio of the first voltage V1 to the second voltage V2 is 2 times, as shown in FIG. Figure 8 In this example, the first voltage V1 is 10V, the second voltage V2 is 5V, and the ratio of the second current I2 to the first current I1 is also 2 times, as shown in FIG. Figure 6 In this example, the second current I2 is 8A, and the first current I1 is 4A.

[0089] On the other hand, in this embodiment, the ratio of the voltage across VC1 of the capacitor C1, the voltage across VC2 of the capacitor C2, and the voltage across VC3 of the capacitor C3 is 1:1:1. Specifically, the voltage across VC1 of the capacitor C1, the voltage across VC2 of the capacitor C2, and the voltage across VC3 of the capacitor C3 are all equal to V2 (for example, but not limited to, corresponding to FIG. 5 and FIG. 6 ). Figure 6 5V in the ).

[0090] Figure 9A and Figure 9B A schematic diagram showing a specific embodiment of a switching conversion unit and its operation in a switched capacitor conversion circuit according to the present invention is shown. Figure 9A and Figure 9B The switching conversion unit 190 has the same hardware configuration as the switching conversion unit 150 , except that the switching conversion unit 190 operates in a 3x conversion mode.

[0091] like Figure 9A and Figure 9BAs shown, in the 3x conversion mode, during the first period PH1 of the switching cycle Ts, the switches Q11, Q12, Q14, Q16, and Q17 are turned on, and the switches Q13, Q15, and Q18 are turned off, so as to control the two ends of the capacitor C1 to be electrically connected to the first power supply and the ground potential, respectively; the two ends of the capacitor C2 to be electrically connected to the first power supply and the second power supply, respectively; and the two ends of the capacitor C3 to be electrically connected to the second power supply and the ground potential, respectively.

[0092] During the second period PH2 of the switching cycle Ts, each of the switches Q11-Q18 operates in a state opposite to that of the first period PH1. That is, switches Q11, Q12, Q14, Q16, and Q17 are non-conducting, while switches Q13, Q15, and Q18 are conductive. This controls the first end of capacitor C1 to float at node N1, the second end of capacitor C1 to be electrically connected to the second power source, and capacitors C2 and C3 to be connected in series and electrically connected between the second power source and the ground potential. It is noteworthy that in this embodiment, during the second period PH2, a voltage VC2 across capacitor C2 is in phase with the second voltage V2, while a voltage VC3 across capacitor C3 is in phase with the second voltage V2.

[0093] Figure 10 Display corresponds to Figure 9A and Figure 9B FIG. 1 is an operational waveform diagram of an embodiment of a switched capacitor converter circuit.

[0094] like Figure 10 As shown, in this embodiment, in the 3x conversion mode, in the steady state, the ratio of the first voltage V1 to the second voltage V2 is 3 times, as shown in FIG. Figure 10 In this example, the first voltage V1 is 15V, the second voltage V2 is 5V, and the ratio of the second current I2 to the first current I1 is also 3 times, as shown in FIG. Figure 6 In this example, the second current I2 is 8A, and the first current I1 is approximately 2.67A.

[0095] It is worth noting that, in this embodiment, Figure 9A and Figure 9B As shown, the switch Q11 includes a transistor Q11a and a transistor Q11b connected in series, wherein the body diode Da of the transistor Q11a and the body diode Db of the transistor Q11b are in opposite directions to prevent current that may be conducted by the body diodes when the switch Q11 is not conducting.

[0096] Figure 11A schematic diagram illustrates a specific embodiment of a switching conversion unit and its operation in a switched capacitor converter circuit according to the present invention. In this embodiment, in bypass mode, switches Q11-Q14 are conductive, and switches Q15-Q18 are non-conductive, such that the first power source and the second power source are directly electrically connected to each other. In other words, the switching conversion unit 1100 of this embodiment operates in a 1x conversion mode.

[0097] Figure 12 A circuit block diagram showing an embodiment of a switched capacitor converter circuit of the present invention is shown.

[0098] The switched capacitor converter circuit 1200 includes a first switching conversion unit 1211 and a second switching conversion unit 1212 connected in parallel between a first power source and a second power source. In one embodiment, the first switching conversion unit 1211 and the second switching conversion unit 1212 switch their corresponding multiple switches in an interleaved phase manner to perform power conversion between the first power source and the second power source, thereby effectively reducing the output voltage (corresponding to V2 or V1) and the input current ripple (corresponding to I1 or I2).

[0099] Please read back Figure 5A 、 Figure 5B and Figure 6 As can be seen from the voltages marked in the figure, in the 4x conversion mode, the drain-source voltage of switches Q12 and Q13 when not conducting is 10V (corresponding to 2*V2), while the drain-source voltage of the other switches when not conducting is 5V (corresponding to V2). On the other hand, in the 3x conversion mode, the drain-source voltage of switch Q13 when not conducting is 10V, while the drain-source voltage of the other switches when not conducting is 5V. In other words, among the multiple switches in the switched capacitor converter circuit of the present invention, the voltage peak experienced by switches Q12 and Q13 during power conversion operation is 2*V2 (corresponding to the first peak voltage), while the voltage peak experienced by the other switches during power conversion operation is only V2 (corresponding to the second peak voltage).

[0100] Therefore, compared to the aforementioned prior art, the present invention requires fewer high-voltage-resistant switches (such as Q12 and Q13), thereby saving costs. In terms of quantity, in quadruple conversion mode, the number of high-voltage-resistant switches required for the switching conversion unit in the present invention is two switches, while the total number of switches required for the switching conversion unit is eight. In other words, only one-quarter of the total number of switches need to have a higher voltage resistance, and the proportion of high-voltage-resistant switches required is less than half of that required by the prior art.

[0101] For example, the withstand voltage of switches Q12 and Q13 can be configured to be 2*V2 plus a safety margin (corresponding to the first withstand voltage), while the withstand voltage of the remaining switches can be configured to be V2 plus a safety margin (corresponding to the second withstand voltage). In one embodiment, the peak voltage and withstand voltage have the following relationship: first withstand voltage > first peak voltage > second withstand voltage > second peak voltage. It should be noted that if the drain-source voltage during operation exceeds the withstand voltage, the switch will be permanently damaged.

[0102] The present invention provides a switched capacitor converter circuit with different conversion ratios. The conversion ratio can be adaptively selected according to power conversion direction, battery voltage, and battery status, to perform switched capacitor power conversion, for example, to charge a battery or convert battery power to provide external power. Furthermore, the switched capacitor converter circuit of the present invention requires only a small number of switches that must withstand high voltages, thereby significantly reducing cost and size.

[0103] The present invention has been described above with respect to the preferred embodiments, but the above description is only for those skilled in the art to easily understand the content of the present invention and is not intended to limit the broadest scope of the present invention. The various embodiments described are not limited to individual applications, but can also be applied in combination. For example, two or more embodiments can be used in combination, and part of the components in one embodiment can also be used to replace the corresponding components in another embodiment. In addition, under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations. For example, the present invention refers to "processing or calculating or generating an output result according to a certain signal", which is not limited to the signal itself, but also includes, when necessary, performing voltage-to-current conversion, current-to-voltage conversion, and / or ratio conversion on the signal, and then processing or calculating the converted signal to generate an output result. It can be seen that under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations, and there are many combinations, which are not listed here one by one. Therefore, the scope of the present invention should cover the above and all other equivalent changes.

Claims

1. A switched capacitor converter circuit for converting a first power source into a second power source or converting the second power source into the first power source, the switched capacitor converter circuit comprising: At least one switching conversion unit; as well as a control circuit for controlling the switching conversion unit; The switching conversion unit includes: a plurality of capacitors, including a first capacitor, a second capacitor, and a third capacitor; and a plurality of switches for periodically switching the plurality of capacitors based on a switching cycle; wherein in a 4x conversion mode, during a first period of the switching cycle, the plurality of switches control the two ends of the first capacitor to be electrically connected to the first power source and the second power source, respectively, and control the second capacitor and the third capacitor to be connected in series and electrically connected between the second power source and a ground potential; wherein during a second period of the switching cycle, the plurality of switches control the two ends of the first capacitor to be electrically connected to the first node and the ground potential, respectively, the two ends of the second capacitor to be electrically connected to the first node and the second power source, respectively, and control the third capacitor to be electrically connected in parallel with the second power source; Power conversion between the first power source and the second power source is performed by this periodic operation, so that in the 4x conversion mode, a ratio of a first voltage of the first power source to a second voltage of the second power source is 4, and a ratio of a second current of the second power source to a first current of the first power source is 4.

2. The switched capacitor converter circuit according to claim 1, wherein: In the 4x conversion mode, in a steady state, the ratio of the voltage across the first capacitor, the voltage across the second capacitor, and the voltage across the third capacitor is 3:2:

1.

3. The switched capacitor conversion circuit according to claim 1, wherein: The plurality of switches include first to eighth switches, wherein the first switch, the second switch, the third switch, and the fourth switch are sequentially coupled in series between the first power source and the second power source, and are sequentially coupled in pairs to a first node, a second node, and a third node. The fifth switch and the sixth switch are serially connected between the second power source and the ground potential and are coupled to each other at a fourth node. The seventh switch and the eighth switch are serially connected between the second power source and the ground potential and are coupled to each other at a fifth node. wherein the first capacitor is coupled between the first node and the fourth node, the second capacitor is coupled between the second node and the fifth node, and the third capacitor is coupled between the third node and the fourth node; wherein in the 4x conversion mode, during the first period, the first switch, the third switch, the fifth switch, and the eighth switch are conductive, and the second switch, the fourth switch, the sixth switch, and the seventh switch are non-conductive, so as to control the first capacitor to be electrically connected between the first power source and the second power source, and control the second capacitor and the third capacitor to be connected in series and electrically connected between the second power source and the ground potential; wherein during the second period, each of the first to eighth switches operates in a state opposite to that of the first period, so as to control the first capacitor and the second capacitor to be connected in series and electrically connected between the second power source and the ground potential, and to control the third capacitor to be connected in parallel and electrically connected to the second power source; The power conversion between the first power source and the second power source is performed by the periodic operation.

4. The switched capacitor conversion circuit according to claim 3, wherein: In a 2x conversion mode, the second switch and the third switch are always on; wherein in the 2x conversion mode, during a first period of the switching cycle, the first switch, the fifth switch, and the seventh switch are turned on, and the fourth switch, the sixth switch, and the eighth switch are turned off, so as to control the first capacitor, the second capacitor, and the third capacitor to be connected in parallel and electrically connected between the first power source and the second power source; wherein during a second period of the switching cycle, the first switch and each of the fourth to eighth switches operate in a state opposite to that of the first period, so as to control the first capacitor, the second capacitor, and the third capacitor to be connected in parallel and electrically connected between the second power source and the ground potential; The periodic operation causes a ratio of the first voltage to the second voltage to be 2, and a ratio of a second current of the second power source to a first current of the first power source to be 2.

5. The switched capacitor conversion circuit according to claim 3, wherein: In a 3x conversion mode, During a first period of the switching cycle, the first switch, the second switch, the fourth switch, the sixth switch, and the seventh switch are turned on, and the third switch, the fifth switch, and the eighth switch are turned off, so as to control the two ends of the first capacitor to be electrically connected to the first power supply and the ground potential, respectively, the two ends of the second capacitor to be electrically connected to the first power supply and the second power supply, respectively, and the two ends of the third capacitor to be electrically connected to the second power supply and the ground potential, respectively; wherein, during a second period of the switching cycle, each of the first to eighth switches operates in a state opposite to that of the first period, so as to control the first end of the first capacitor to float, the second end of the first capacitor to be electrically connected to the second power source, and the second capacitor and the third capacitor to be connected in series and electrically connected between the second power source and the ground potential; The periodic operation causes a ratio of the first voltage to the second voltage to be 3, and a ratio of a second current of the second power source to a first current of the first power source to be 3.

6. The switched capacitor conversion circuit according to claim 5, wherein: The first switch includes a first transistor and a second transistor connected in series, wherein a body diode of the first transistor and a body diode of the second transistor are opposite to each other.

7. The switched capacitor conversion circuit according to claim 3, wherein: In a bypass mode, the first to fourth switches are turned on, and the fifth to eighth switches are turned off, so that the first power source and the second power source are directly electrically connected to each other.

8. The switched capacitor conversion circuit according to claim 3, wherein: The at least one switching conversion unit includes a first switching conversion unit and a second switching conversion unit, which are connected in parallel between the first power source and the second power source. The first switching conversion unit and the second switching conversion unit switch the corresponding multiple switches in an interlaced phase manner to perform power conversion between the first power source and the second power source.

9. The switched capacitor conversion circuit according to claim 3, wherein: The multiple switches in the first part have a first withstand voltage and the voltage peak they withstand during the power conversion operation is a first peak voltage, and the multiple switches in the second part have a second withstand voltage and the voltage peak they withstand during the power conversion operation is a second peak voltage, wherein the first peak voltage is twice the second peak voltage.

10. The switched capacitor conversion circuit according to claim 9, wherein: The number of the switches in the first portion is less than 1 / 2 of the total number of the switches, and the number of the switches in the second portion is more than 1 / 2 of the total number of the switches.

11. The switched capacitor converter circuit according to claim 9, wherein: In the quadruple conversion mode, the plurality of switches in the first portion include the second switch and the third switch, and the plurality of switches in the second portion include the first switch and fourth to eighth switches.

12. The switched capacitor converter circuit according to claim 9 or claim 11, wherein: The first peak voltage, the second peak voltage, the first withstand voltage, and the second withstand voltage have the following relationship: first withstand voltage > first peak voltage > second withstand voltage > second peak voltage.

13. A switching conversion unit for converting a first power source into a second power source or converting the second power source into the first power source, the switching conversion unit comprising: a plurality of capacitors, including a first capacitor, a second capacitor, and a third capacitor; and a plurality of switches for periodically switching the plurality of capacitors based on a switching cycle; wherein in a 4x conversion mode, during a first period of the switching cycle, the plurality of switches control the two ends of the first capacitor to be electrically connected to the first power source and the second power source, respectively, and control the second capacitor and the third capacitor to be connected in series and electrically connected between the second power source and a ground potential; wherein during a second period of the switching cycle, the plurality of switches control the two ends of the first capacitor to be electrically connected to the first node and the ground potential, respectively, the two ends of the second capacitor to be electrically connected to the first node and the second power source, respectively, and control the third capacitor to be electrically connected in parallel with the second power source; Power conversion between the first power source and the second power source is performed by this periodic operation, so that in the 4x conversion mode, a ratio of a first voltage of the first power source to a second voltage of the second power source is 4, and a ratio of a second current of the second power source to a first current of the first power source is 4.

14. The switching conversion unit according to claim 13, wherein: The plurality of switches include first to eighth switches, wherein the first switch, the second switch, the third switch, and the fourth switch are sequentially coupled in series between the first power source and the second power source, and are sequentially coupled in pairs to a first node, a second node, and a third node. The fifth switch and the sixth switch are serially connected between the second power source and the ground potential and are coupled to each other at a fourth node. The seventh switch and the eighth switch are serially connected between the second power source and the ground potential and are coupled to each other at a fifth node. wherein the first capacitor is coupled between the first node and the fourth node, the second capacitor is coupled between the second node and the fifth node, and the third capacitor is coupled between the third node and the fourth node; wherein in the 4x conversion mode, during the first period, the first switch, the third switch, the fifth switch, and the eighth switch are conductive, and the second switch, the fourth switch, the sixth switch, and the seventh switch are non-conductive, so as to control the first capacitor to be electrically connected between the first power source and the second power source, and control the second capacitor and the third capacitor to be connected in series and electrically connected between the second power source and the ground potential; wherein during the second period, each of the first to eighth switches operates in a state opposite to that of the first period, so as to control the first capacitor and the second capacitor to be connected in series and electrically connected between the second power source and the ground potential, and to control the third capacitor to be connected in parallel and electrically connected to the second power source; The power conversion between the first power source and the second power source is performed by the periodic operation.

15. The switching conversion unit according to claim 14, wherein: In a 2x conversion mode, the second switch and the third switch are always on; wherein in the 2x conversion mode, during a first period of the switching cycle, the first switch, the fifth switch, and the seventh switch are turned on, and the fourth switch, the sixth switch, and the eighth switch are turned off, so as to control the first capacitor, the second capacitor, and the third capacitor to be connected in parallel and electrically connected between the first power source and the second power source; wherein during a second period of the switching cycle, the first switch and each of the fourth to eighth switches operate in a state opposite to that of the first period, so as to control the first capacitor, the second capacitor, and the third capacitor to be connected in parallel and electrically connected between the second power source and the ground potential; The periodic operation causes a ratio of the first voltage to the second voltage to be 2, and a ratio of a second current of the second power source to a first current of the first power source to be 2.

16. The switching conversion unit according to claim 14, wherein: In a 3x conversion mode, During a first period of the switching cycle, the first switch, the second switch, the fourth switch, the sixth switch, and the seventh switch are turned on, and the third switch, the fifth switch, and the eighth switch are turned off, so as to control the two ends of the first capacitor to be electrically connected to the first power supply and the ground potential, respectively, the two ends of the second capacitor to be electrically connected to the first power supply and the second power supply, respectively, and the two ends of the third capacitor to be electrically connected to the second power supply and the ground potential, respectively; wherein, during a second period of the switching cycle, each of the first to eighth switches operates in a state opposite to that of the first period, so as to control the first end of the first capacitor to float, the second end of the first capacitor to be electrically connected to the second power source, and the second capacitor and the third capacitor to be connected in series and electrically connected between the second power source and the ground potential; The periodic operation causes a ratio of the first voltage to the second voltage to be 3, and a ratio of a second current of the second power source to a first current of the first power source to be 3.

17. The switching conversion unit according to claim 16, wherein: The first switch includes a first transistor and a second transistor connected in series, wherein a body diode of the first transistor and a body diode of the second transistor are opposite to each other.

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