Switching capacitor converter

Abstract

The present invention discloses a switched capacitor converter. By controlling the on-off states of multiple transistors in each switched capacitor unit, any M-1 adjacent switched capacitor units are selected to participate in the operation, and the flying capacitors in the switched capacitor units with serial numbers smaller than the serial number of the selected switched capacitor units are connected in parallel to the output end to be used as output filter capacitors; the flying capacitors in the switched capacitor units with serial numbers larger than the serial number of the selected switched capacitor units are connected in series with the flying capacitors in the selected switched capacitor units, and are jointly configured as part of a flying capacitor with an M-to-1 ratio. This can achieve the adjustment of the input voltage to output voltage ratio of the switched capacitor converter to M-to-1. When M takes different values, different ratios can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and more particularly to a switched capacitor converter. Background Art

[0002] In existing fast-charging applications like mobile phones, charge pump charging is the primary solution, offering exceptionally high efficiency. A 2:1 charge pump circuit, capable of providing 30W to 50W of charging power, is the current mainstream solution in the market. Mid-range and high-end flagship models, pursuing even higher charging power, are beginning to utilize a 4:1 charge pump circuit. To be compatible with mainstream mid-power adapters, a 4:1 charge pump circuit requires a 2:1 transformer ratio. Summary of the Invention

[0003] In view of this, the present invention provides a switched capacitor converter with adjustable transformation ratio.

[0004] In a first aspect, the present invention provides a switched capacitor converter, characterized in that it includes:

[0005] N-1 switched capacitor units connected in sequence, with serial numbers decreasing by 1 from N-1, each of the switched capacitor units including a flying capacitor and a plurality of transistors;

[0006] Among them, by controlling the on-off states of the multiple transistors in each of the switching capacitor units, any adjacent M-1 switching capacitor units are selected to participate in the work, so as to achieve a transformation ratio of the input voltage to the output voltage of the switching capacitor converter of M to 1, where 1≤M≤N, and M and N are both natural numbers.

[0007] Preferably, each of the switching capacitor units includes a flying capacitor and three transistors, wherein, except for the switching capacitor unit with the smallest serial number, the first power end of the first transistor of the three transistors in other switching capacitor units is connected to the second end of the flying capacitor in the switching capacitor unit with the current serial number, and the second power end is connected to the first end of the flying capacitor in the adjacent switching capacitor unit.

[0008] Preferably, the first power terminal of the second transistor among the three transistors is connected to the output positive terminal of the switching capacitor converter, and the second power terminal is connected to the first terminal of the flying capacitor in the current switching capacitor unit; the first power terminal of the third transistor among the three transistors is connected to the ground terminal, and the second power terminal is connected to the second terminal of the flying capacitor in the switching capacitor unit of the current serial number.

[0009] Preferably, selecting any adjacent M-1 switching capacitor units to participate in the operation means that at least two transistors in the selected switching capacitor units operate in a switching state, and the flying capacitor therein is configured as a part of a flying capacitor with an M to 1 ratio.

[0010] Preferably, among the selected switching capacitor units, when the switching capacitor unit with the largest sequence number N-1 is included, the first transistors, the second transistors and the third transistors in all the switching capacitor units are configured to be in a switching state.

[0011] Preferably, among the selected switching capacitor units, when the switching capacitor unit with the largest serial number N-1 is not included, the first transistor and the third transistor in the switching capacitor unit with the largest serial number are both configured to be in a switching state, and the second transistor is configured to be in a normally-off state; the first transistor, the second transistor and the third transistor in the other switching capacitor units except the switching capacitor unit with the largest serial number are all configured to be in a switching state.

[0012] Preferably, among the unselected switching capacitor units, when the serial number is smaller than the serial number of the selected switching capacitor unit, the flying capacitor therein is connected in parallel to the output end to be used as an output filter capacitor, wherein the switching capacitor unit with the largest serial number is close to the positive end of the input voltage, and the switching capacitor unit with the smallest serial number is close to the output end.

[0013] Preferably, in the unselected switching capacitor unit, when the serial number is smaller than the serial number of the selected switching capacitor unit, the second transistor and the third transistor therein are configured to be in a normally-on state, and the first transistor is configured to be in a normally-off state.

[0014] Preferably, in the unselected switching capacitor unit, when the serial number is greater than the serial number of the selected switching capacitor unit, the flying capacitor therein is connected in series with the flying capacitor in the selected switching capacitor unit and is jointly configured as a part of the flying capacitor with an M to 1 ratio.

[0015] Preferably, in the unselected switching capacitor unit, when the serial number is greater than the serial number of the selected switching capacitor unit, the first transistor therein is configured to be in a normally-on state.

[0016] Preferably, in the unselected switching capacitor unit, when the serial number is greater than the serial number of the selected switching capacitor unit, at least one of the second transistor and the third transistor therein is configured to be in a normally-off state.

[0017] Preferably, in a switching capacitor unit that is not selected and whose serial number is greater than the serial number of the selected switching capacitor unit, when its serial number is not the maximum serial number N-1, the second transistor and the third transistor therein are both configured to be in a normally-off state; when its serial number is the maximum serial number N-1, the third transistor therein is configured to be in a normally-off state, and the second transistor is configured to be in a switching state.

[0018] Preferably, the switching capacitor unit with a larger serial number is selected to participate in the work to achieve a transformation ratio of the input voltage to the output voltage of the switching capacitor converter of M to 1, so that the efficiency is higher, wherein the switching capacitor unit with the largest serial number is close to the positive end of the input voltage, and the switching capacitor unit with the smallest serial number is close to the output end.

[0019] Preferably, the switched capacitor unit with the largest serial number N-1 and its adjacent switched capacitor units are selected to participate in the operation, so as to achieve a transformation ratio of the input voltage to the output voltage of the switched capacitor converter of M to 1, so as to achieve the highest efficiency.

[0020] Preferably, it further comprises a transistor, one power end of which is connected to the first end of the flying capacitor in the switch capacitor unit numbered N-1, and the other power end of which is connected to the positive end of the input voltage.

[0021] Preferably, by controlling the on-off states of the multiple transistors in each of the switching capacitor units, N-1 switching capacitor units are all involved in the operation, so as to achieve a transformation ratio of the input voltage to the output voltage of the switching capacitor converter of N to 1.

[0022] The present invention aims to provide a switched capacitor converter, which controls the on-off states of multiple transistors in each switched capacitor unit so that any adjacent M-1 switched capacitor units are selected to participate in the operation, and the flying capacitors in the switched capacitor units with serial numbers smaller than the serial number of the selected switched capacitor unit are connected in parallel to the output end to be used as output filter capacitors; the flying capacitors in the switched capacitor units with serial numbers larger than the serial number of the selected switched capacitor unit are connected in series with the flying capacitors in the selected switched capacitor unit, and are jointly configured as part of a flying capacitor with an M to 1 ratio, so as to realize the input voltage V BUS With the output voltage V out The transformation ratio is adjusted to M to 1. When M takes different values, different transformation ratios can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0024] Figure 1 is a schematic diagram of a switched capacitor converter according to a first embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of a switched capacitor converter according to a second embodiment of the present invention;

[0026] Figure 3 is a driving timing diagram of a switched capacitor converter according to a second embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of a switched capacitor converter according to a third embodiment of the present invention;

[0028] Figure 5 is an equivalent circuit diagram of a switched capacitor converter in different working stages according to a third embodiment of the present invention;

[0029] Figure 6 is a driving timing diagram of a switched capacitor converter according to a third embodiment of the present invention;

[0030] Figure 7 is a schematic diagram of a switched capacitor converter according to a fourth embodiment of the present invention;

[0031] Figure 8 is an equivalent circuit diagram of a switched capacitor converter in different working stages according to a fourth embodiment of the present invention;

[0032] Figure 9 is a driving timing diagram of a switched capacitor converter according to a fourth embodiment of the present invention;

[0033] Figure 10 is a schematic diagram of a switched capacitor converter according to a fifth embodiment of the present invention;

[0034] Figure 11 is an equivalent circuit diagram of a switched capacitor converter in different working stages according to a fifth embodiment of the present invention;

[0035] Figure 12 is a driving timing diagram of a switched capacitor converter according to a fifth embodiment of the present invention;

[0036] Figure 13 is a schematic diagram of a switched capacitor converter according to a sixth embodiment of the present invention;

[0037] Figure 14 is an equivalent circuit diagram of a switched capacitor converter in different working stages according to a sixth embodiment of the present invention;

[0038] Figure 15 FIG. 4 is a driving timing diagram of a switched capacitor converter according to a sixth embodiment of the present invention. DETAILED DESCRIPTION

[0039] The present invention is described below based on the following embodiments, but the present invention is not limited to these embodiments. In the detailed description of the present invention below, certain specific details are described in detail. Those skilled in the art can fully understand the present invention without these details. To avoid obscuring the essence of the present invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0040] Furthermore, persons of ordinary skill in the art will appreciate that the figures provided herein are for illustration purposes only and are not necessarily drawn to scale.

[0041] At the same time, it should be understood that in the following description, "circuit" refers to a conductive loop composed of at least one element or subcircuit connected electrically or electromagnetically. When an element or circuit is said to be "connected to" another element or an element / circuit is said to be "connected" between two nodes, it can be directly coupled or connected to the other element or there can be intermediate elements. The connection between the elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there are no intermediate elements between the two.

[0042] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include," "comprising," and similar words should be construed in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to."

[0043] In the description of the present invention, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0044] Figure 1 FIG. 1 is a schematic diagram of a switched capacitor converter according to a first embodiment of the present invention. Figure 1 As shown, the switched capacitor converter of this embodiment includes N-1 switched capacitor units connected in sequence, and the serial numbers of the N-1 switched capacitor units are 1, 2, 3 to N-1, where N is an integer greater than 1. Among them, the switched capacitor unit with the largest serial number, that is, the switched capacitor unit N-1, is close to the input voltage V BUS The positive end of the switch capacitor unit with the smallest serial number is close to the input voltage V BUS negative terminal.

[0045] Preferably, each switched capacitor unit includes a flying capacitor and three transistors, wherein, except for the switched capacitor unit with the smallest sequence number 1, the first power terminal of the first transistor among the three transistors in the other switched capacitor units is connected to the second terminal of the flying capacitor in the switched capacitor unit with the current sequence number, and the second power terminal is connected to the first terminal of the flying capacitor in the adjacent switched capacitor unit. The first power terminal of the first transistor in the switched capacitor unit with the smallest sequence number 1 is connected to the second terminal of the flying capacitor in the switched capacitor unit with the current sequence number, and the second power terminal is connected to the output terminal. The first power terminal of the second transistor among the three transistors is connected to the positive output terminal of the switched capacitor converter, and the second power terminal is connected to the first terminal of the flying capacitor in the current switched capacitor unit; the first power terminal of the third transistor among the three transistors is connected to the ground terminal, and the second power terminal is connected to the second terminal of the flying capacitor in the switched capacitor unit with the current sequence number.

[0046] refer to Figure 1 In the example, the switch capacitor unit 2 with serial number 2 is taken as an example. The first transistor of the three transistors is Q4, the second transistor is Q5, and the third transistor is Q6. The first power terminal of the first transistor Q4 is connected to the flying capacitor C in the switch capacitor unit 2. FLY2 The second end of the second power terminal is connected to the flying capacitor C in the switch capacitor unit 1 FLY1 The first power terminal of the second transistor Q5 is connected to the positive output terminal of the switched capacitor converter, and the second power terminal is connected to the flying capacitor C in the switched capacitor unit 2. FLY2 The first power terminal of the third transistor Q6 is connected to the ground terminal, and the second power terminal is connected to the flying capacitor C in the switch capacitor unit 2. FLY2 In the largest switched capacitor unit N-1, the flying capacitor is C FLY(N-1) Among the three transistors, the first transistor is Q(3N-5), the second transistor is Q(3N-4), and the third transistor is Q(3N-3).

[0047] It can be deduced from this that in any switched capacitor unit n with serial number n, 1≤n≤(N-1), the flying capacitor is C FLYn Among the three transistors, the first transistor is Q(3n-2), the second transistor is Q(3n-1), and the third transistor is Q(3n).

[0048] In addition, the switched capacitor converter further includes a transistor Q(3N-3), one power terminal of which is connected to the flying capacitor C in the switched capacitor unit numbered N-1. FLY(N-1) The first end of the power supply is connected to the input voltage V BUS The right end.

[0049] The switching capacitor converter of the present invention aims to control the on-off states of multiple transistors in each switching capacitor unit so that any adjacent M-1 switching capacitor units are selected to participate in the operation, thereby achieving the goal of reducing the input voltage V BUS With the output voltage V out The transformation ratio is adjusted to M to 1, where 1≤M≤N, and M and N are both natural numbers. When any adjacent P-1 switching capacitor units are selected to participate in the operation, the input voltage V BUS With the output voltage V out The transformation ratio is adjusted to P to 1, where 1≤P≤N, and P≠M. It can be seen that any number of adjacent switched capacitor units can be selected to participate in the work to achieve the input voltage V BUS With the output voltage V out The transformation ratio is adjusted to different ratios.

[0050] Of course, it should be noted that if the on-off states of multiple transistors in each switched capacitor unit are controlled so that N-1 switched capacitor units all participate in the operation, the transformation ratio of the input voltage to the output voltage of the switched capacitor converter is N to 1.

[0051] It should also be noted that, in the present invention, selecting any M-1 adjacent switched capacitor units for operation means that at least two transistors in the selected switched capacitor units are operating in a switching state, and the flying capacitors in the selected switched capacitor units are configured as part of the flying capacitor of the switched capacitor converter with an M-to-1 ratio. Transistors operating in a switching state refer to an operating state that is different from a normally-on state and a normally-off state, and is controlled by a PWM signal to alternately turn on and off.

[0052] Furthermore, among the selected switching capacitor units, when the switching capacitor unit with the largest sequence number N-1 is included, the first transistors, the second transistors and the third transistors in all the switching capacitor units are configured to be in a switching state.

[0053] Among the selected switching capacitor units, when the switching capacitor unit with the largest serial number N-1 is not included, the first transistor and the third transistor in the switching capacitor unit with the largest serial number are both configured to be in the switching state, and the second transistor is configured to be in the normally-off state; the first transistor, the second transistor and the third transistor in the other switching capacitor units except the switching capacitor unit with the largest serial number are all configured to be in the switching state.

[0054] Specifically, when any adjacent M-1 switching capacitor units are selected to participate in the work, in the unselected switching capacitor units, when the serial number is less than the serial number of the selected switching capacitor unit, the second transistor and the third transistor therein are configured to be in a normally on state, and the first transistor is configured to be in a normally off state so that the flying capacitor therein is connected in parallel to the output end to be used as an output filter capacitor; when the serial number is greater than the serial number of the selected switching capacitor unit, the first transistor therein is configured to be in a normally on state, and at least one of the second transistor and the third transistor is configured to be in a normally off state so that the flying capacitor therein is connected in series with the flying capacitor in the selected switching capacitor unit, and are jointly configured as part of the flying capacitor with an M to 1 ratio.

[0055] More specifically, in a switching capacitor unit that is not selected and whose serial number is greater than the serial number of the selected switching capacitor unit, when its serial number is not the maximum serial number N-1, the second transistor and the third transistor therein are both configured to be in a normally-off state; when its serial number is the maximum serial number N-1, the third transistor therein is configured to be in a normally-off state, and the second transistor is configured to be in a switching state.

[0056] It can be seen that the switched capacitor converter of the present invention can realize the switching of the input voltage V BUS With the output voltage V out The transformation ratio is adjusted to the different ratios required.

[0057] Figure 2 Schematic diagram of a switched capacitor converter according to a second embodiment of the present invention. In the following embodiments, a 4:1 series-parallel charge pump circuit (i.e., N=4, with three switched capacitor units) is used as an example for illustration. Figure 3 The driving timing diagram of the switched capacitor converter of the second embodiment of the present invention is shown, which introduces the use of a 4-to-1 series-parallel charge pump circuit to achieve the input voltage V BUS With the output voltage V out The working process has a transformation ratio of 4 to 1.

[0058] From the above analysis, we know that if the ratio of the input voltage to the output voltage of the switched capacitor converter is to be N:1, then all N-1 switched capacitor units must be in operation. Therefore, when the 4:1 series-parallel charge pump circuit operates at a ratio of 4:1, all three switched capacitor units are in operation, and all transistors are operating in the switching state.

[0059] Specifically, the driving timings of transistors Q1 , Q4 , Q7 , and Q10 are the same, and the driving signals are denoted as GH. The driving timings of transistors Q2 , Q3 , Q5 , Q6 , Q8 , and Q9 are the same, and the driving signals are denoted as GL.

[0060] When the driving signal GH is high, there is:

[0061] V BUS =V out +VC FLY1 +VC FLY2 +VC FLY3

[0062] Among them, VC FLY1 VC FLY2 VC FLY3 They are respectively the flying capacitors C FLY1 , flying capacitor C FLY2 And the flying capacitor C FLY3 The pressure drop across the terminals.

[0063] When the driving signal GL is at a high level,

[0064] V out =VC FLY1 =VC FLY2 =VC FLY3

[0065] Therefore,

[0066] Figure 4 FIG3 is a schematic diagram of a switched capacitor converter according to a third embodiment of the present invention. Figure 5 The equivalent circuit diagram of the switched capacitor converter of the third embodiment of the present invention at different working stages is shown, and Figure 6 The driving timing diagram of the switched capacitor converter of the third embodiment of the present invention is shown, which introduces the first method of using a 4-to-1 series-parallel charge pump circuit to realize the input voltage V BUS With the output voltage V out The ratio of the working process is 2 to 1. Here M = 2, so only one switching capacitor unit is selected when the 4 to 1 series-parallel charge pump circuit works.

[0067] Specifically, in the embodiment of the present invention, the switch capacitor unit 1 is selected to participate in the work, and the switch capacitor units 2 and 3 are not fully selected to participate in the work. In the switch capacitor units 2 and 3 that are not selected, their serial numbers are all greater than the serial number 1 of the selected switch capacitor unit. Therefore, the first transistors Q4 and Q7 in the switch capacitor units 2 and 3 are configured to be in a normally on state, as shown by the solid line in the figure, and the second transistor Q5 and the third transistor Q6 in the switch capacitor unit 2, the third transistor Q9 in the switch capacitor unit 3, and the second transistor Q2 in the switch capacitor unit 1 are all configured to be in a normally off state, as shown by the dotted line in the figure, so as to connect the flying capacitors C in the switch capacitor units 2 and 3. FLY2 and C FLY3 The flying capacitor C in the selected switched capacitor unit 1 FLY1 When connected in series, they are collectively configured as a flying capacitor with a 2 to 1 ratio.

[0068] Transistors Q1, Q3, Q8, and Q10 are in a switching state, and the driving timing of transistors Q1 and Q10 is the same, and the driving signal is GH. The driving timing of transistors Q3 and Q8 is the same, and the driving signal is GL.

[0069] When the driving signal GH is at a high level, Figure 5 As shown in (a), we have:

[0070] V BUS =V out +VC FLY1 +VC FLY2 +VC FLY3

[0071] When the driving signal GL is at a high level, Figure 5 As shown in (b), we have:

[0072] V out =VC FLY1 +VC FLY2 +VC FLY3

[0073] Therefore,

[0074] Figure 7 FIG. 4 is a schematic diagram of a switched capacitor converter according to a fourth embodiment of the present invention. Figure 8 The equivalent circuit diagrams of the switched capacitor converter of the fourth embodiment of the present invention at different working stages are shown, and Figure 9 The driving timing diagram of the switched capacitor converter of the fourth embodiment of the present invention is shown, which introduces the second method of using a 4-to-1 series-parallel charge pump circuit to realize the input voltage V BUS With the output voltage V out The working process has a transformation ratio of 2 to 1.

[0075] Specifically, in the embodiment of the present invention, the switch capacitor unit 2 is selected to participate in the work, and the switch capacitor units 1 and 3 are not fully selected to participate in the work. In the switch capacitor units 1 and 3 that are not selected, the serial number 1 is smaller than the serial number 2 of the selected switch capacitor unit, then the second transistor Q2 and the third transistor Q3 in the switch capacitor unit 1 are configured to be in a normally-on state, and the first transistor Q1 is configured to be in a normally-off state to connect the flying capacitor C FLY1 connected in parallel to the output terminal to be used as an output filter capacitor; if the serial number 3 is greater than the serial number 2 of the selected switching capacitor unit, the first transistor Q7 in the switching capacitor unit 3 is configured to be in a normally on state, and the third transistor Q9 is configured to be in a normally off state, so as to FLY3 The flying capacitor C in the selected switched capacitor unit 2 FLY2 After being connected in series, they are collectively configured as a flying capacitor with a 2:1 ratio. In addition, the second transistor Q5 in the switch capacitor unit 2 is also in a normally-off state.

[0076] Transistors Q4, Q6, Q8 and Q10 are in switching state, and the driving timing of transistors Q4 and Q10 is the same, and the driving signal is GH. The driving timing of transistors Q6 and Q8 is the same, and the driving signal is GL.

[0077] When the driving signal GH is at a high level, Figure 8 As shown in (a), we have:

[0078] V BUS =V out +VC FLY2 +VC FLY3

[0079] When the driving signal GL is at a high level, Figure 8 As shown in (b), we have:

[0080] V out =VC FLY2 +VC FLY3

[0081] Therefore,

[0082] Figure 10 FIG. 5 is a schematic diagram of a switched capacitor converter according to a fifth embodiment of the present invention. Figure 11 The equivalent circuit diagrams of the switched capacitor converter of the fifth embodiment of the present invention at different working stages are shown, and Figure 12 The driving timing diagram of the switched capacitor converter of the fifth embodiment of the present invention is shown, which introduces the third method of using a 4-to-1 series-parallel charge pump circuit to realize the input voltage V BUSWith the output voltage V out The working process has a transformation ratio of 2 to 1.

[0083] Specifically, in the embodiment of the present invention, the switch capacitor unit 3 is selected to participate in the work, and the switch capacitor units 1 and 2 are not fully selected to participate in the work. In the switch capacitor units 1 and 2 that are not selected, the serial numbers 1 and 2 are both smaller than the serial number 3 of the selected switch capacitor unit, then the second transistors Q2, Q5 and the third transistors Q3, Q6 in the switch capacitor units 1 and 2 are all configured to be in a normally-on state, and the first transistors Q1, Q4 are both configured to be in a normally-off state to connect the flying capacitor C FLY1 and C FLY2 The flying capacitor C in the switched capacitor unit 3 is connected in parallel to the output terminal to be used as an output filter capacitor. FLY3 Individually configured as a flying capacitor with a 2:1 ratio.

[0084] Transistors Q7, Q8, Q9 and Q10 are in switching state, and the driving timing of transistors Q7 and Q10 is the same, and the driving signal is GH. The driving timing of transistors Q9 and Q8 is the same, and the driving signal is GL.

[0085] When the driving signal GH is at a high level, Figure 11 As shown in (a), we have:

[0086] V BUS =V out +VC FLY3

[0087] When the driving signal GL is at a high level, Figure 11 As shown in (b), we have:

[0088] V out =VC FLY3

[0089] Therefore,

[0090] Thus, it can be seen that the switched capacitor converter of the present invention controls the on-off state of multiple transistors in each switched capacitor unit so that any adjacent M-1 switched capacitor units are selected to participate in the work, and the flying capacitors in the switched capacitor units with serial numbers smaller than the serial numbers of the selected switched capacitor units are connected in parallel to the output end to be used as output filter capacitors; the flying capacitors in the switched capacitor units with serial numbers greater than the serial numbers of the selected switched capacitor units are connected in series with the flying capacitors in the selected switched capacitor units, and are jointly configured as part of the flying capacitor with an M to 1 ratio, so as to realize the input voltage V BUS With the output voltage V outThe transformation ratio is adjusted to M to 1. When M takes different values, different transformation ratios can be obtained.

[0091] Specifically, in a 4-to-1 series-parallel charge pump circuit, when all the switched capacitor units of all serial numbers are involved in the work, a 4-to-1 ratio function can be achieved; when a switched capacitor unit of a different serial number is selected to participate in the work, a 2-to-1 ratio function can be achieved. Therefore, the 4-to-1 series-parallel charge pump circuit of the present invention can be efficiently compatible with mainstream adapters on the market.

[0092] Furthermore, by comparing the third, fourth, and fifth embodiments, it can be seen that when a switching capacitor unit with a larger serial number is selected to participate in the operation to achieve a transformation ratio of the input voltage to the output voltage of the switched capacitor converter of M to 1, since there is no normally-on transistor in series in the flying capacitor path of the M to 1 transformation ratio, the impedance in the loop is greatly reduced, so that there is no loss caused by current flowing through the transistor on-resistance, thereby achieving higher efficiency and better system performance. Furthermore, it can be seen that the highest efficiency can be achieved by selecting the switching capacitor unit with serial number N-1 (i.e., the largest serial number) and its adjacent switching capacitor units to participate in the operation to achieve a transformation ratio of the input voltage to the output voltage of the switched capacitor converter of M to 1.

[0093] Specifically, in a 4-to-1 series-parallel charge pump circuit, the highest efficiency can be achieved when the switching capacitor unit numbered 3 is selected to work to achieve a transformation ratio of the input voltage to the output voltage of the switching capacitor converter of 2:1.

[0094] Figure 13 FIG. 6 is a schematic diagram of a switched capacitor converter according to a sixth embodiment of the present invention. Figure 14 The equivalent circuit diagrams of the switched capacitor converter of the sixth embodiment of the present invention at different working stages are shown, and Figure 15 The driving timing diagram of the switched capacitor converter of the sixth embodiment of the present invention is shown, which introduces a method of using a 4-to-1 series-parallel charge pump circuit to realize the input voltage V BUS With the output voltage V out The working process has a transformation ratio of 3 to 1.

[0095] Preferably, in the embodiment of the present invention, the switch capacitor units 3 and 2 are selected to participate in the work, and the switch capacitor unit 1 is not fully selected to participate in the work. When the serial number of the unselected switch capacitor unit 1 is smaller than the serial numbers 3 and 2 of the selected switch capacitor units, the second transistor Q2 and the third transistor Q3 in the switch capacitor unit 1 are both configured to be in a normally-on state, and the first transistor Q1 is configured to be in a normally-off state to connect the flying capacitor C FLY1 Connected in parallel to the output terminal to be used as an output filter capacitor. The flying capacitor C in the switched capacitor unit 3 and 2 FLY3 and CFLY2 They are connected in series to form a flying capacitor with a 3:1 ratio configuration.

[0096] Transistors Q4, Q5, Q6, Q7, Q8, Q9, and Q10 are in switching states, and the driving timing of transistors Q4, Q7, and Q10 is the same, and the driving signal is GH. The driving timing of transistors Q5, Q6, Q8, and Q9 is the same, and the driving signal is GL.

[0097] When the driving signal GH is at a high level, Figure 14 As shown in (a), we have:

[0098] V BUS =V out +VC FLY3 +VC FLY2

[0099] When the driving signal GL is at a high level, Figure 14 As shown in (b), we have:

[0100] V out =VC FLY3 =VC FLY2

[0101] Therefore,

[0102] Of course, it should be noted that, in the embodiment of the present invention, the switch capacitor units 1 and 2 may also be selected to participate in the work to realize the input voltage V BUS With the output voltage V out The transformation ratio is 3 to 1. The selection of switched capacitor units 3 and 2 for operation is based on the above analysis and the consideration of optimal efficiency.

[0103] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A switched capacitor converter, characterized in that: include: N-1 switched capacitor units, numbered N-1 and decreasing by 1, are sequentially connected between the positive terminal and the negative terminal of the input voltage, each of the switched capacitor units comprising a flying capacitor and a plurality of transistors; By controlling the on-off states of the multiple transistors in each of the switch capacitor units, any adjacent M-1 switch capacitor units are selected to participate in the operation, wherein the flying capacitors in the switch capacitor units with serial numbers smaller than the selected serial number are connected in parallel to the output end, and the flying capacitors in the switch capacitor units with serial numbers greater than the selected serial number are connected in series with the flying capacitors in the selected switch capacitor units, so as to achieve a transformation ratio of the input voltage to the output voltage of M to 1, where 1≤M<N, and M and N are both natural numbers; and One power terminal is connected to the first terminal of the flying capacitor in the switch capacitor unit numbered N-1, and the other power terminal is connected to the transistor at the positive terminal of the input voltage.

2. The switched capacitor converter according to claim 1, wherein: Each of the switching capacitor units includes a flying capacitor and three transistors, wherein, except for the switching capacitor unit with the smallest serial number, the first power end of the first transistor of the three transistors in other switching capacitor units is connected to the second end of the flying capacitor in the switching capacitor unit with the current serial number, and the second power end is connected to the first end of the flying capacitor in the adjacent switching capacitor unit.

3. The switched capacitor converter according to claim 2, wherein: The first power terminal of the second transistor among the three transistors is connected to the output positive terminal of the switching capacitor converter, and the second power terminal is connected to the first terminal of the flying capacitor in the current switching capacitor unit; the first power terminal of the third transistor among the three transistors is connected to the ground terminal, and the second power terminal is connected to the second terminal of the flying capacitor in the switching capacitor unit of the current sequence number.

4. The switched capacitor converter according to claim 3, wherein: Selecting any adjacent M-1 switching capacitor units to participate in the operation means that at least two transistors in the selected switching capacitor unit operate in a switching state, and the flying capacitor therein is configured as a part of a flying capacitor with an M to 1 ratio.

5. The switched capacitor converter according to claim 4, wherein: Among the selected switching capacitor units, when the switching capacitor unit with the largest sequence number N-1 is included, the first transistors, the second transistors and the third transistors in all the switching capacitor units are configured to be in a switching state.

6. The switched capacitor converter according to claim 4, wherein: Among the selected switching capacitor units, when the switching capacitor unit with the largest serial number N-1 is not included, the first transistor and the third transistor in the switching capacitor unit with the largest serial number are both configured to be in the switching state, and the second transistor is configured to be in the normally off state.

7. The switched capacitor converter according to claim 1, wherein: Among the unselected switching capacitor units, when the serial number is smaller than the serial number of the selected switching capacitor unit, the flying capacitor therein is connected in parallel to the output end to be used as an output filter capacitor, wherein the switching capacitor unit with the largest serial number is close to the positive end of the input voltage, and the switching capacitor unit with the smallest serial number is close to the output end.

8. The switched capacitor converter according to claim 3, wherein: In the unselected switching capacitor unit, when the serial number is smaller than the serial number of the selected switching capacitor unit, the second transistor and the third transistor therein are configured to be in a normally-on state, and the first transistor is configured to be in a normally-off state.

9. The switched capacitor converter according to claim 1, wherein: In the unselected switching capacitor unit, when the serial number is greater than the serial number of the selected switching capacitor unit, the flying capacitor therein is connected in series with the flying capacitor in the selected switching capacitor unit and is jointly configured as a part of the flying capacitor with an M to 1 ratio.

10. The switched capacitor converter according to claim 3, wherein: In the unselected switch capacitor unit, when the serial number is greater than the serial number of the selected switch capacitor unit, the first transistor therein is configured to be in a normally-on state.

11. The switched capacitor converter according to claim 10, wherein: In the unselected switching capacitor units, when the serial number is greater than the serial number of the selected switching capacitor unit, at least one of the second transistor and the third transistor in each of the switching capacitor units is configured to be in a normally-off state.

12. The switched capacitor converter according to claim 11, wherein: In a switching capacitor unit that is not selected and whose serial number is greater than the serial number of a selected switching capacitor unit, when its serial number is not the maximum serial number N-1, the second transistor and the third transistor therein are both configured to be in a normally-off state; when its serial number is the maximum serial number N-1, the third transistor therein is configured to be in a normally-off state, and the second transistor is configured to be in a switching state.

13. The switched capacitor converter according to claim 1, wherein: The switching capacitor unit with a larger serial number is selected to participate in the work to achieve a transformation ratio of the input voltage to the output voltage of the switching capacitor converter of M to 1, so that the efficiency is higher, wherein the switching capacitor unit with the largest serial number is close to the positive end of the input voltage, and the switching capacitor unit with the smallest serial number is close to the output end.

14. The switched capacitor converter according to claim 13, wherein: The switched capacitor unit with the largest serial number N-1 and its adjacent switched capacitor units are selected to participate in the operation, so as to achieve a transformation ratio of the input voltage to the output voltage of the switched capacitor converter of M to 1, so as to achieve the highest efficiency.

15. The switched capacitor converter according to claim 1, wherein: By controlling the on-off states of the multiple transistors in each of the switching capacitor units, N-1 switching capacitor units are all involved in the operation, so as to achieve a transformation ratio of the input voltage to the output voltage of the switching capacitor converter of N to 1.

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