Charge pump circuit
The charge pump circuit addresses limitations in boost ratio adjustment by using a charging stand, capacitors, reactors, and FETs to achieve continuous and low-loss voltage conversion between 1 and 2 times, including step-down capabilities.
Patent Information
- Application Number
- JP2023221407
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-12-27
- Publication Date
- 2025-07-09
Smart Images
Figure 2025103781000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a charge pump circuit.
Background Art
[0002] Patent Document 1 discloses a boost circuit provided with switching means in a plurality of boost cell groups that boost an input voltage and output it, so that each boost cell group can be changed to a series, parallel, or series-parallel connection configuration.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the technology disclosed in Patent Document 1, for example, boosting with a boost ratio less than 2 times, such as a boost ratio of 1.5 times, cannot be realized, and step-down in the reverse direction cannot be performed either. Also, for example, there are technologies for selecting a plurality of boost ratios, but it is difficult to continuously change (make variable) the boost ratio.
[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a charge pump circuit capable of continuously and with low loss changing the boost ratio.
Means for Solving the Problems
[0006] The charge pump circuit according to the present disclosure includes a charging stand, a battery connected in series with the charging stand, a first capacitor connected in parallel with the charging stand, a reactor and a second capacitor connected in series with each other and connected in parallel with the charging stand, a first FET, a second FET, a fifth FET, and a sixth FET connected to the charging stand, a third FET and a fourth FET connected in series with each other and connected in parallel with the charging stand, a third capacitor and a fourth capacitor connected in series with each other and connected in parallel with the charging stand, and a control unit. The control unit implements a 1.5-fold boost mode by implementing a 1-fold boost ratio mode and a 2-fold boost ratio mode in a predetermined order, and implements the 1.5-fold boost ratio mode and the 1-fold boost ratio mode in a predetermined order, or implements the 1.5-fold boost ratio mode and the 2-fold boost ratio mode in a predetermined order to perform arbitrary boosting between 1 and 2 times the boost ratio.
Advantages of the Invention
[0007] According to the present disclosure, the boost ratio can be continuously and low-loss changed.
Brief Description of the Drawings
[0008]
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Embodiments for Carrying Out the Invention
[0009] The charge pump circuit according to the embodiment of the present disclosure will be described with reference to the drawings. Note that the constituent elements in the following embodiments include those that can be replaced by those skilled in the art and are easy to replace, or those that are substantially the same.
[0010] (Circuit Configuration) The configuration of the charge pump circuit according to the embodiment will be described with reference to FIGS. 1, 2, 3, and 5. The charge pump circuit according to the embodiment is a charge pump type step-up / step-down circuit. The charge pump circuit according to the embodiment is applied to, for example, a high-power DCDC converter mounted on a battery electric vehicle (BEV) or a fuel cell vehicle (FCV).
[0011] As shown in FIG. 1, the charge pump circuit 1 includes a charging stand 11, a battery 12, a reactor 21, a first capacitor 31, a second capacitor 32, a third capacitor 33, and a fourth capacitor 34. In addition to the above, the charge pump circuit 1 further includes a first FET 41, a second FET 42, a third FET 43, a fourth FET 44, a fifth FET 45, a sixth FET 46, and a control unit 60. Among the components of the charge pump circuit 1, the components excluding the charging stand 11 and the battery 12 correspond to the vehicle charging unit 50.
[0012] The charging stand 11 is provided, for example, in a charging station or the like and outputs a predetermined voltage (for example, 400V). The charging stand 11 is connected in series with the first FET 41, the second FET 42, the fifth FET 45, the sixth FET 46, and the battery 12. The charging stand 11, the first capacitor 31, the reactor 21, the second capacitor 32, the third FET 43 and the fourth FET 44, and the third capacitor 33 and the fourth capacitor 34 are connected in parallel, respectively.
[0013] The battery 12 corresponds to the vehicle battery and outputs a predetermined voltage (for example, 400V). This battery 12 is connected in series with the charging stand 11. The battery 12 is also connected in series with the charging stand 11, the first FET 41, the second FET 42, the fifth FET 45, and the sixth FET 46. The battery 12, the first capacitor 31, the reactor 21, the second capacitor 32, the third FET 43 and the fourth FET 44, and the third capacitor 33 and the fourth capacitor 34 are connected in parallel, respectively.
[0014] The reactor 21 is a reactor for resonance. The second capacitor 32 is a capacitor for resonance. Therefore, the reactor 21 and the second capacitor 32 constitute an LC resonator. The reactor 21 and the second capacitor 32 are connected in series with each other. The reactor 21 and the second capacitor 32 are connected in parallel with the charging stand 11 and the battery 12.
[0015] The first capacitor 31, the third capacitor 33, and the fourth capacitor 34 are capacitors for voltage smoothing. The first capacitor 31 is connected in parallel with the charging stand 11 and the battery 12. The third capacitor 33 and the fourth capacitor 34 are connected in series with each other and are connected in parallel with the charging stand 11 and the battery 12.
[0016] The first FET 41, the second FET 42, the third FET 43, the fourth FET 44, the fifth FET 45, and the sixth FET 46 are all insulated gate field effect transistors (MOSFETs: Metal-Oxide-Semiconductor Field Effect Transistors). This MOSFET is a semiconductor element having the functions of a switch and a diode. In the following description, the first FET 41, the second FET 42, the third FET 43, the fourth FET 44, the fifth FET 45, and the sixth FET 46 may be simply referred to as "switching elements".
[0017] The first FET 41 is connected in series in the reverse direction with respect to the charging stand 11. That is, the first FET 41 allows the current from the charging stand 11 to flow when switched on and blocks the current from the charging stand 11 when switched off. Note that "in the reverse direction with respect to the charging stand 11" specifically indicates that the diode of the MOSFET is facing the direction of the charging stand 11.
[0018] In the charge pump circuit 1, the first FET 41 is serially connected to the charging stand 11, but it may also be connected in parallel to the charging stand 11. For example, the first FET 41 can also be arranged at the position of X in FIG. 1 with the diode facing downward. However, by serially connecting the first FET 41 in the reverse direction with respect to the charging stand 11 as in the charge pump circuit 1, for example, when an abnormal current flows from the charging stand 11 side, this current can be blocked by the first FET 41. That is, the first FET 41 in the charge pump circuit 1 functions as a current blocking mechanism.
[0019] The second FET 42 is serially connected to the charging stand 11 in the forward direction. Specifically, "in the forward direction with respect to the charging stand 11" indicates that the diode of the MOSFET faces the opposite direction to the charging stand 11 side.
[0020] In the charge pump circuit 1, the second FET 42 is serially connected to the charging stand 11, but it may also be connected in parallel to the charging stand 11. For example, the second FET 42 can also be arranged at the position of Y in FIG. 1 with the diode facing upward.
[0021] The third FET 43 and the fourth FET 44 are serially connected to each other and are also connected in parallel to the charging stand 11 and the battery 12. Also, the third FET 43 and the fourth FET 44 are connected in the reverse direction with respect to the charging stand 11. Moreover, the midpoint of the third FET 43 and the fourth FET 44 is connected to the midpoint of the third capacitor 33 and the fourth capacitor 34.
[0022] The fifth FET 45 and the sixth FET 46 are serially connected to the charging stand 11 in the forward direction. Also, the fifth FET 45, the sixth FET 46, the third capacitor 33, and the fourth capacitor 34 are serially connected to each other.
[0023] In the charge pump circuit 1, as will be described later, when performing a boosting operation (or a bucking operation), a plurality of current paths are formed. In the present embodiment, for convenience, these current paths are defined as mode Z, mode A, mode B, mode C, and mode D.
[0024] Mode Z is a path through which the current from the charging stand 11 flows through the first FET 41, the fifth FET 45, the battery 12, the sixth FET 46, and the second FET 42, as shown in FIG. 2, for example. Also, mode A is a path through which the current from the first capacitor 31 flows through the first FET 41, the reactor 21, the second capacitor 32, and the second FET 42, as shown in the upper left of FIG. 3, for example. Also, mode B is a path through which the current from the second capacitor 32 flows through the third FET 43, the fourth capacitor 34, and the sixth FET 46, as shown in the upper right of FIG. 5, for example.
[0025] Also, mode C is a path through which the current from the second capacitor 32 flows through the fifth FET 45, the third capacitor 33, and the fourth FET 44, as shown in the lower left of FIG. 5, for example. Also, mode D is a path through which the current from the second capacitor 32 flows through the reactor 21, the fifth FET 45, the third capacitor 33, the fourth capacitor 34, and the sixth FET 46, as shown in the upper right of FIG. 3, for example. The arrangement of each element in the charge pump circuit 1 is not limited to the arrangement in FIG. 1 as long as the current paths of the above modes can be maintained (each mode can be switched), that is, if the types of elements through which the current flows are the same, it may be changed as necessary.
[0026] The control unit 60 controls each element of the charge pump circuit 1. This control unit 60 is an electronic control unit (ECU) mainly composed of a microcomputer including, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc.
[0027] The control unit 60 implements a 1.5-fold boost ratio mode by implementing a 1-fold boost ratio mode and a 2-fold boost ratio mode in a predetermined order. Then, the control unit 60 implements an arbitrary boost within the range of 1 to 2 times the boost ratio by implementing the 1.5-fold boost ratio mode and the 1-fold boost ratio mode in a predetermined order, or by implementing the 1.5-fold boost ratio mode and the 2-fold boost ratio mode in a predetermined order.
[0028] Specifically, the control unit 60 implements an arbitrary boost within the range of 1 to 1.5 times the boost ratio by implementing the 1.5-fold boost ratio mode and the 1-fold boost ratio mode in a predetermined order. Also, specifically, the control unit 60 implements an arbitrary boost within the range of 1.5 to 2 times the boost ratio by implementing the 1.5-fold boost ratio mode and the 2-fold boost ratio mode in a predetermined order. Hereinafter, the realization methods of the modes of each boost ratio will be described.
[0029] (Method 1 for realizing a 1-fold boost ratio) A method 1 for realizing a 1-fold boost ratio (first 1-fold boost ratio mode) using the charge pump circuit according to the embodiment will be described with reference to FIG. 2. As shown in FIG. 2, the control unit 60 can implement the first 1-fold boost ratio mode by turning on the first FET 41 and flowing a direct current (DC current) from the charging stand 11 through the first FET 41, the fifth FET 45, the battery 12, the sixth FET 46, and the second FET 42. In this embodiment, the current path in this first 1-fold boost ratio mode is defined as "mode Z".
[0030] In the first 1-fold boost ratio mode, current is flowed without performing switching with the first FET 41 turned on. For example, assume that the voltage of the battery 12 (battery voltage) is 400V and a current of, for example, 400A is required from the vehicle side. In this case, a current of 400A is flowed at 405V obtained by adding a voltage (e.g., 5V) for pushing the current from the charging stand 11. As a result, a current of 400A is pushed in due to a voltage difference of 5V and supplied to the battery 12. Since this first 1-fold boost ratio mode does not perform switching of the switching element, boost can be performed efficiently.
[0031] (Method 2 for achieving a 1x boost ratio) A method 2 for achieving a 1x boost ratio (second 1x boost ratio mode) using the charge pump circuit according to the embodiment will be described with reference to FIGS. 3 and 4. The control unit 60 implements the second 1x boost ratio mode by implementing modes A and D in a predetermined order, for example, as shown in FIG. 3. Here, modes A and D are alternately implemented in the order of mode A, mode D, mode A, mode D,.... Hereinafter, the details of each mode will be described clockwise from mode A in the upper left of FIG. 3.
[0032] (1) In mode A, the first FET 41 among the switching elements is turned on, and the charge charged from the charging stand 11 to the first capacitor 31 is transferred to the second capacitor 32. For example, when the voltage of the charging stand 11 (stand voltage) is 400V, since the charging stand 11 and the first capacitor 31 are always connected, the first capacitor 31 is also charged to 400V. Then, by turning on the first FET 41 from this state, the current path of mode A is energized, and the charge moves from the first capacitor 31 to the second capacitor 32.
[0033] (2) In mode D, the first FET 41 is turned off, and the charge charged in the second capacitor 32 is transferred to the third capacitor 33 and the fourth capacitor 34. In this mode D, by turning off the first FET 41 that was turned on in the immediately preceding mode A, the current path of mode D is energized, and the charge moves from the second capacitor 32 to the third capacitor 33 and the fourth capacitor 34.
[0034] (3) In mode A, the first FET 41 among the switching elements is turned on, and the charge charged from the charging stand 11 to the first capacitor 31 is transferred to the second capacitor 32.
[0035] (4) In mode D, the first FET 41 is turned off, and the charge charged in the second capacitor 32 is transferred to the third capacitor 33 and the fourth capacitor 34.
[0036] In this way, in the second voltage boost ratio 1x mode, switching is performed by the first FET 41, and while operating the charge pump, a voltage boost ratio of 1x is achieved. That is, in the second voltage boost ratio 1x mode, for example, by bucketing the 400V current supplied from the charging stand 11, the third capacitor 33 and the fourth capacitor 34 are charged to a total of 400V. And since the third capacitor 33 and the fourth capacitor 34 are always connected to the battery 12, the battery 12 is also charged to 400V.
[0037] Here, the LC resonator composed of the reactor 21 and the second capacitor 32 oscillates a sine wave as shown in, for example, FIG. 4. In FIG. 4, L1 represents the reactor, C1 represents the first capacitor 31, C2 represents the second capacitor 32, C3 represents the third capacitor 33, and C4 represents the fourth capacitor 34, respectively.
[0038] Therefore, as shown in FIG. 4, the control unit 60 switches each mode when the current (C2 current) of the second capacitor 32 becomes 0 in the period associated with the resonance frequency of the LC resonator composed of the reactor 21 and the second capacitor 32.
[0039] That is, the control unit 60 switches from mode A to mode D at the moment when the charge moves from the first capacitor 31 (C1) to the second capacitor 32 (C2) on the upper side (positive half-wave) of the sine wave and the power of the second capacitor 32 (C2) becomes 0. Subsequently, the control unit 60 switches from mode D to mode A at the moment when the charge moves from the second capacitor 32 (C2) to the third capacitor 33 (C3) and the fourth capacitor 34 (C4) on the lower side (negative half-wave) of the sine wave and the power of the second capacitor 32 (C2) becomes 0.
[0040] In this way, by performing soft switching (0 current / 0 voltage switching) by the first FET 41 at the timing when the power of the second capacitor 32 (C2) becomes 0, voltage boost can be performed while minimizing switching losses.
[0041] (Method for realizing a voltage boost ratio of 2 times) A method for realizing a voltage boost ratio of 2 times (voltage boost ratio 2 times mode) using the charge pump circuit according to the embodiment will be described with reference to FIGS. 5 and 6. The control unit 60 implements the voltage boost ratio 2 times mode by implementing modes A, B, A, and C in a predetermined order. Here, the modes are implemented in the order of mode A, mode B, mode A, mode C,.... Hereinafter, the details of each mode will be described clockwise from mode A in the upper left of FIG. 5.
[0042] (1) In mode A, the first FET 41 among the switching elements is turned on, and the charge charged from the charging stand 11 to the first capacitor 31 is transferred to the second capacitor 32. For example, when the voltage of the charging stand 11 (stand voltage) is 400V, since the charging stand 11 and the first capacitor 31 are always connected, the first capacitor 31 is also charged to 400V. Then, by turning on the first FET 41 from this state, the current path of mode A is energized, and the charge moves from the first capacitor 31 to the second capacitor 32.
[0043] (2) In mode B, the first FET 41 is turned off and the third FET 43 is turned on, and the charge charged to the second capacitor 32 is transferred to the fourth capacitor 34. In this mode B, the first FET 41 that was turned on in the previous mode A is turned off, and further the third FET 43 is turned on, so that the current path of mode B is energized, and the charge moves from the second capacitor 32 to the fourth capacitor 34. In this way, for example, by bucketing and relaying the 400V current supplied from the charging stand 11, the fourth capacitor 34 is charged to 400V.
[0044] (3) In mode A, the first FET 41 is turned on and the third FET 43 is turned off, and the charge charged from the charging stand 11 to the first capacitor 31 is transferred to the second capacitor 32.
[0045] (4) In mode C, the first FET 41 is turned off and the fourth FET 44 is turned on, and the charge stored in the second capacitor 32 is transferred to the third capacitor 33. In this mode C, the first FET 41 that was on in the immediately preceding mode A is turned off, and the fourth FET 44 is further turned on, thus energizing the current path of mode C and causing the charge to move from the second capacitor 32 to the third capacitor 33.
[0046] In this way, in the doubling boost ratio mode, switching is performed by the first FET 41, the third FET 43, and the fourth FET 44, and while operating the charge pump, the doubling of the boost ratio is realized. That is, in the doubling boost ratio mode, for example, by buck-boosting the 400V current supplied from the charging stand 11, the third capacitor 33 and the fourth capacitor 34 are each charged to 400V (total 800V). And since the third capacitor 33 and the fourth capacitor 34 are always connected to the battery 12, the battery 12 is also charged to 800V.
[0047] Here, the LC resonator composed of the reactor 21 and the second capacitor 32 oscillates a sine wave as shown in, for example, FIG. 6. In FIG. 6, L1 represents the reactor 21, C1 represents the first capacitor 31, C2 represents the second capacitor 32, C3 represents the third capacitor 33, and C4 represents the fourth capacitor 34, respectively.
[0048] Therefore, as shown in FIG. 6, the control unit 60 switches each mode when the current (C2 current) of the second capacitor 32 is 0 in the period associated with the resonance frequency of the LC resonator composed of the reactor 21 and the second capacitor 32.
[0049] That is, the control unit 60 switches from mode A to mode B at the moment when the charge moves from the first capacitor 31 (C1) to the second capacitor 32 (C2) on the upper side (positive half-wave) of the sine wave and the power of the second capacitor 32 (C2) becomes zero. Subsequently, the control unit 60 switches from mode B to mode A at the moment when the charge moves from the second capacitor 32 (C2) to the fourth capacitor 34 (C4) on the lower side (negative half-wave) of the sine wave and the power of the second capacitor 32 (C2) becomes zero. Subsequently, the control unit 60 switches from mode A to mode C at the moment when the charge moves from the first capacitor 31 (C1) to the second capacitor 32 (C2) on the upper side (positive half-wave) of the sine wave and the power of the second capacitor 32 (C2) becomes zero. Subsequently, the control unit 60 switches from mode C to mode A at the moment when the charge moves from the second capacitor 32 (C2) to the third capacitor 33 (C3) on the lower side (negative half-wave) of the sine wave and the power of the second capacitor 32 (C2) becomes zero.
[0050] In this way, by performing soft switching (zero current / zero voltage switching) by the first FET 41, the third FET 43, and the fourth FET 44 at the timing when the power of the second capacitor 32 (C2) becomes zero, boosting can be performed while minimizing switching losses.
[0051] (Method for realizing a boost ratio of 1.5 times) A method for realizing a boost ratio of 1.5 times (boost ratio 1.5 times mode) using the charge pump circuit according to the embodiment will be described with reference to FIG. 7. The control unit 60 implements the boost ratio 1.5 times mode by implementing the boost ratio 1 times mode and the boost ratio 2 times mode in a predetermined order. The control unit 60 implements the boost ratio 1.5 times mode by implementing, for example, modes A, B, A, D, A, C, A, D in a predetermined order as shown in FIG. 7. Here, the modes are implemented in the order of mode A, mode B, mode A, mode D, mode A, mode C, mode A, mode D... The details of each mode will be described below in a clockwise direction starting from mode A in the upper left of FIG. 7.
[0052] (1) In mode A, the first FET 41 among each switching element is turned on, and the charge charged from the charging stand 11 to the first capacitor 31 is transferred to the second capacitor 32. For example, when the voltage of the charging stand 11 (stand voltage) is 400V, since the charging stand 11 and the first capacitor 31 are always connected, the first capacitor 31 is also charged at 400V. Then, by turning on the first FET 41 from this state, the current path of mode A is energized, and the charge moves from the first capacitor 31 to the second capacitor 32.
[0053] (2) In mode B, the first FET 41 is turned off and the third FET 43 is turned on, and the charge charged to the second capacitor 32 is transferred to the fourth capacitor 34. In this mode B, the first FET 41 that was turned on in the previous mode A is turned off, and further the third FET 43 is turned on, so that the current path of mode B is energized, and the charge moves from the second capacitor 32 to the fourth capacitor 34. Thus, for example, by bucketing the 400V current supplied from the charging stand 11, the fourth capacitor 34 is charged at 400V.
[0054] (3) In mode A, the first FET 41 is turned on and the third FET 43 is turned off, and the charge charged from the charging stand 11 to the first capacitor 31 is transferred to the second capacitor 32.
[0055] (4) In mode D, the first FET 41 is turned off, and the charge charged to the second capacitor 32 is transferred to the third capacitor 33 and the fourth capacitor 34. In this mode D, by turning off the first FET 41 that was turned on in the previous mode A, the current path of mode D is energized, and the charge moves from the second capacitor 32 to the third capacitor 33 and the fourth capacitor 34.
[0056] (5) In mode A, the first FET 41 is turned on, and the charge charged from the charging stand 11 to the first capacitor 31 is transferred to the second capacitor 32.
[0057] (6) In mode C, the first FET 41 is turned off and the fourth FET 44 is turned on, and the charge charged in the second capacitor 32 is transferred to the third capacitor 33. In this mode C, the first FET 41 that was on in the immediately preceding mode A is turned off, and further the fourth FET 44 is turned on, so that the current path in mode C is energized and the charge moves from the second capacitor 32 to the third capacitor 33.
[0058] (7) In mode A, the first FET 41 is turned on and the fourth FET 44 is turned off, and the charge charged from the charging stand 11 to the first capacitor 31 is transferred to the second capacitor 32.
[0059] (8) In mode D, the first FET 41 is turned off, and the charge charged in the second capacitor 32 is transferred to the third capacitor 33 and the fourth capacitor 34.
[0060] Thus, in the 1.5 - fold boost ratio mode, switching is performed by the first FET 41, the third FET 43, and the fourth FET 44, and while operating the charge pump, a 1.5 - fold boost ratio is realized. That is, in the 1.5 - fold boost ratio mode, as shown in FIG. 7, by alternately performing the mode transition with a 2 - fold boost ratio and the mode transition with a 1 - fold boost ratio, an intermediate voltage between the 2 - fold boost ratio and the 1 - fold boost ratio is obtained, and a 1.5 - fold boost ratio is realized.
[0061] Here, in FIG. 7, the modes are alternately switched in the order of 2 - fold boost ratio, 1 - fold boost ratio, 2 - fold boost ratio, 1 - fold boost ratio... By switching alternately in this way, there is an advantage that the voltage fluctuation at the time of switching becomes small. On the other hand, the switching between the 1 - fold boost ratio and the 2 - fold boost ratio does not have to be alternating. For example, even if the switching is performed in the order of 1 - fold boost ratio, 1 - fold boost ratio, 2 - fold boost ratio, 2 - fold boost ratio... or in the order of 2 - fold boost ratio, 2 - fold boost ratio, 1 - fold boost ratio, 1 - fold boost ratio..., it is possible to realize a 1.5 - fold boost ratio. That is, it is only necessary that the average boost ratio is 1.5 times, and the switching order between the 1 - fold boost ratio and the 2 - fold boost ratio is not particularly limited.
[0062] Note that even in the 1.5 - fold boost mode, the control unit 60 switches each mode at the period associated with the resonance frequency of the LC resonator composed of the reactor 21 and the second capacitor 32 when the current (C2 current) of the second capacitor 32 becomes 0. In this way, by performing soft switching (0 - current / 0 - voltage switching) using the first FET 41, the third FET 43, and the fourth FET 44 at the timing when the power of the second capacitor 32 (C2) becomes 0, boosting can be performed while minimizing switching losses.
[0063] (Method for realizing a boost ratio of 1 to 1.5 times) As shown in FIG. 8, the control unit 60 can implement a 1.25 - fold boost mode by implementing the 1 - fold boost mode and the 1.5 - fold boost mode in a predetermined order. Also, the control unit 60 can implement a 1.125 - fold boost mode by implementing the 1.25 - fold boost mode and the 1 - fold boost mode in a predetermined order. Further, the control unit 60 can continuously change the boost ratio between 1 and 1.5 times by integrating (merging) the 1 - fold boost mode or the 2 - fold boost mode with respect to them.
[0064] (Method for realizing a boost ratio of 1.5 to 2 times) As shown in FIG. 8, the control unit 60 can implement a 1.75 - fold boost mode by implementing the 1.5 - fold boost mode and the 2 - fold boost mode in a predetermined order. Also, the control unit 60 can implement a 1.875 - fold boost mode by implementing the 1.75 - fold boost mode and the 2 - fold boost mode in a predetermined order. Further, the control unit 60 can continuously change the boost ratio between 1.5 and 2 times by integrating (merging) the 1 - fold boost mode or the 2 - fold boost mode with respect to them.
[0065] (Method for realizing a buck ratio of 0.5 times) A method for realizing a step-down ratio of 0.5 times (step-down ratio 0.5 times mode) using the charge pump circuit according to the embodiment will be described with reference to FIG. 9. In the previous description, in the charge pump circuit 1, the case where the current from the charging stand 11 is boosted and supplied to the battery 12 has been described. Conversely, it is also possible to step down the current from the battery 12 and supply it to the charging stand 11.
[0066] In this case, the control unit 60 performs control opposite to that of the above-described boost ratio 2 times mode. That is, the control unit 60 implements the modes C, A, B, A in which the direction of the current is opposite (counterclockwise) to that in the boost ratio 2 times mode in a predetermined order, as shown in FIG. 9 for example, to implement the step-down ratio 0.5 times mode. Here, the modes are implemented in the order of mode C, mode A, mode B, mode A... The details of each mode will be described below in a clockwise direction starting from mode C in the upper left of FIG. 9.
[0067] (1) In mode C, the fifth FET 45 among the switching elements is turned on, and the charge charged in the third capacitor 33 is transferred to the second capacitor 32. For example, when the voltage of the battery 12 (battery voltage) is 400V, since the battery 12, the third capacitor 33, and the fourth capacitor 34 are always connected, the third capacitor 33 and the fourth capacitor 34 are also charged to 400V (200V each). Then, by turning on the fifth FET 45 from this state, the current path of mode C is energized, and the charge moves from the third capacitor 33 to the second capacitor 32. In this way, for example, by buckling half of the 400V current supplied from the battery 12, the second capacitor 32 is charged to 200V.
[0068] (2) In mode A, the first FET 41 is turned off and the second FET 42 is turned on, and the charge charged in the second capacitor 32 is transferred to the first capacitor 31. In this mode A, the fifth FET 45 that was turned on in the previous mode C is turned off, and further the second FET 42 is turned on, so that the current path of mode A is energized, and the charge moves from the second capacitor 32 to the first capacitor 31.
[0069] (3) In mode B, the second FET 42 is turned off and the sixth FET 46 is turned on, and the charge charged in the fourth capacitor 34 is transferred to the second capacitor 32. In this mode B, the first FET 41 that was turned on in the immediately preceding mode A is turned off, and further, by turning on the sixth FET 46, the current path of mode B is energized, and the charge moves from the fourth capacitor 34 to the second capacitor 32.
[0070] (4) In mode A, the second FET 42 is turned on and the sixth FET 46 is turned off, and the charge charged in the second capacitor 32 is transferred to the first capacitor 31.
[0071] In this way, in the step-down ratio 0.5 times mode, switching is performed by the second FET 42, the fifth FET 45, and the sixth FET 46, and while operating the charge pump, a step-down ratio of 0.5 times is realized. That is, in the step-down ratio 0.5 times mode, for example, by buck-boosting the 400V current supplied from the battery 12, the first capacitor 31 is charged at 200V. And since the first capacitor 31 and the charging stand 11 are always connected, the charging stand 11 is also charged at 200V.
[0072] Note that even in the step-down ratio 0.5 times mode, the control unit 60 switches each mode at the period associated with the resonance frequency of the LC resonator composed of the reactor 21 and the second capacitor 32 when the current (C2 current) of the second capacitor 32 is 0. In this way, by performing soft switching (0 current / 0 voltage switching) by the second FET 42, the fifth FET 45, and the sixth FET 46 at the timing when the power of the second capacitor 32 (C2) becomes 0, it is possible to perform step-down while minimizing switching loss.
[0073] Note that the method of realizing a step-down ratio of 0.5 to 1 times by the charge pump circuit 1 may be applied by the methods of realizing a boost ratio of 1 to 1.5 times and a boost ratio of 1.5 to 2 times described above (see FIG. 8).
[0074] (Dedicated charging circuit) An example of the case where the charge pump circuit according to the embodiment is configured as a dedicated charging circuit will be described with reference to FIG. 10. When the charge pump circuit according to the embodiment is configured as a dedicated charging circuit, for example, like the charge pump circuit 1A in FIG. 10, MOSFETs arranged in the forward direction with respect to the charging stand are replaced with diodes. That is, in the charge pump circuit 1A, the second FET 42, the fifth FET 45, and the sixth FET 46 of the charge pump circuit 1 are replaced with diodes 47, 48, and 49, respectively.
[0075] In this way, in the charge pump circuit 1A, MOSFETs (the second FET 42, the fifth FET 45, and the sixth FET 46) that do not perform switching during charging from the charging stand 11 to the battery 12 are changed to inexpensive diodes 47, 48, and 49. Thereby, the manufacturing cost can be reduced.
[0076] (Dedicated power supply circuit) An example of the case where the charge pump circuit according to the embodiment is configured as a dedicated power supply circuit will be described with reference to FIG. 11. When the charge pump circuit according to the embodiment is configured as a dedicated power supply circuit, for example, like the charge pump circuit 1B in FIG. 11, MOSFETs arranged in the reverse direction with respect to the charging stand 11 are replaced with diodes. That is, in the charge pump circuit 1B, the first FET 41, the third FET 43, and the fourth FET 44 of the charge pump circuit 1 are replaced with diodes 47, 48, and 49, respectively.
[0077] In this way, in the charge pump circuit 1B, MOSFETs (the first FET 41, the third FET 43, and the fourth FET 44) that do not perform switching during charging from the battery 12 to the charging stand 11 are changed to inexpensive diodes 47, 48, and 49. Thereby, the manufacturing cost can be reduced.
[0078] (Other modifications) In the previous description, the charge pump circuits 1, 1A, and 1B each having only one battery 12 were described, but the number of batteries 12 is not particularly limited. For example, the charge pump circuit 1C shown in FIG. 12 includes a battery 13 in addition to the battery 12.
[0079] The battery 12 and the battery 13 are connected in series with each other. Also, the midpoint of the battery 12 and the battery 13 is connected to the midpoint of the third capacitor 33 and the fourth capacitor 34. Thus, also in the charge pump circuit 1C including a plurality of batteries 12 and 13, the control unit 60 performs the 1.5 - fold boost mode and the 1 - fold boost mode in a predetermined order, thereby performing an arbitrary boost within the range of 1 to 1.5 times the boost ratio. Further, the control unit 60 performs the 1.5 - fold boost mode and the 2 - fold boost mode in a predetermined order, thereby performing an arbitrary boost within the range of 1.5 to 2 times the boost ratio.
[0080] Here, in the conventional charge pump circuits, for example, it was possible to select a boost ratio of 1 time, 2 times, etc., but it was difficult to continuously change it. On the other hand, in the charge pump circuit according to the embodiment, the 1.5 - fold boost mode and the 1 - fold boost mode are performed in a predetermined order, or the 1.5 - fold boost mode and the 2 - fold boost mode are performed in a predetermined order. Thereby, in the charge - pump type step - up / step - down circuit, the boost ratio (or the buck ratio) can be continuously and with low loss changed.
[0081] Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various changes can be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.
Description of Reference Numerals
[0082] 1, 1A, 1B, 1C Charge pump circuit 11 Charging stand 12, 13 Battery 21 Reactor 31 First Capacitor 32 Second Capacitor 33 Third Capacitor 34 Fourth Capacitor 41 First FET 42 Second FET 43 Third FET 44 Fourth FET 45 Fifth FET 46 Sixth FET 47, 48, 49 Diodes 50 Charging Unit 60 Control Unit
Claims
1. A charging stand, a battery connected in series with the charging stand, a first capacitor connected in parallel with the charging stand, a reactor and a second capacitor connected in series with each other and connected in parallel with the charging stand, a first FET, a second FET, a fifth FET, and a sixth FET connected to the charging stand, a third FET and a fourth FET connected in series with each other and connected in parallel with the charging stand, a third capacitor and a fourth capacitor connected in series with each other and connected in parallel with the charging stand, a control unit, and comprising, wherein the control unit implements a 1.5 - fold boost mode by implementing a 1 - fold boost mode and a 2 - fold boost mode in a predetermined order, implements any boost within a range of 1 to 2 times the boost ratio by implementing the 1.5 - fold boost mode and the 1 - fold boost mode in a predetermined order, or by implementing the 1.5 - fold boost mode and the 2 - fold boost mode in a predetermined order, a charge pump circuit.
2. The first FET is connected in series in the reverse direction with respect to the charging stand, the second FET, the fifth FET, and the sixth FET are connected in series in the forward direction with respect to the charging stand, The charge pump circuit according to Claim 1.
3. The control unit turns on the first FET and implements the 1 - fold boost mode by causing a direct current from the charging stand to flow through the first FET, the fifth FET, the battery, the sixth FET, and the second FET. The charge pump circuit according to Claim 1.
4. The control unit has a mode A in which the first FET is turned on and the charge charged from the charging stand to the first capacitor is transferred to the second capacitor, and a mode D in which the first FET is turned off and the charge charged to the second capacitor is transferred to the third capacitor and the fourth capacitor, and implements the 1 - fold boost mode by implementing them in a predetermined order, The charge pump circuit according to Claim 1.
5. The control unit has a mode A in which the first FET is turned on and the charge charged from the charging stand to the first capacitor is transferred to the second capacitor, and a mode B in which the first FET is turned off and the third FET is turned on, and the charge charged to the second capacitor is transferred to the fourth capacitor, A mode A in which the first FET is turned on and the third FET is turned off, and the charge charged from the charging stand to the first capacitor is transferred to the second capacitor; A mode C in which the first FET is turned off and the fourth FET is turned on, and the charge charged to the second capacitor is transferred to the third capacitor; By implementing in a predetermined order, the boost ratio 2x mode is implemented. The charge pump circuit according to claim 1.
6. The control unit A mode A in which the first FET is turned on and the charge charged from the charging stand to the first capacitor is transferred to the second capacitor; A mode B in which the first FET is turned off and the third FET is turned on, and the charge charged to the second capacitor is transferred to the fourth capacitor; A mode A in which the first FET is turned on and the third FET is turned off, and the charge charged from the charging stand to the first capacitor is transferred to the second capacitor; A mode D in which the first FET is turned off and the charge charged to the second capacitor is transferred to the third capacitor and the fourth capacitor; A mode A in which the first FET is turned on and the charge charged from the charging stand to the first capacitor is transferred to the second capacitor; A mode C in which the first FET is turned off and the fourth FET is turned on, and the charge charged to the second capacitor is transferred to the third capacitor; A mode A in which the first FET is turned on and the fourth FET is turned off, and the charge charged from the charging stand to the first capacitor is transferred to the second capacitor; A mode D in which the first FET is turned off and the charge charged to the second capacitor is transferred to the third capacitor and the fourth capacitor; By implementing in a predetermined order, the boost ratio 1.5x mode is implemented. The charge pump circuit according to claim 1.
7. The control unit implements the boost ratio 1.5x mode and the boost ratio 1x mode in a predetermined order, so as to perform an arbitrary boost between a boost ratio of 1 and 1.
5. The charge pump circuit according to claim 1.
8. The charge pump circuit according to claim 1, wherein the control unit performs any boosting between 1.5 times and 2 times the boosting ratio by performing the 1.5-fold boosting ratio mode and the 2-fold boosting ratio mode in a predetermined order.
9. The charge pump circuit according to any one of claims 3 to 8, wherein the control unit switches each mode when the current of the second capacitor is 0 in a period associated with the resonance frequency of the LC resonator constituted by the reactor and the second capacitor.
Citation Information
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