Control circuits, switched-capacitor converters, and vehicles

Abstract

To provide a control circuit capable of shortening a length of time for activation of a switched capacitor converter.SOLUTION: A control circuit (2) is a control circuit of a switched capacitor converter (SCC2) including a plurality of capacitors (C1 to C3), and a plurality of switching elements (M1 to M8). The control circuit includes: a control unit (CNT1) configured to control switching of the plurality of switching elements; and a charging unit (1) configured to charge at least some of the plurality of capacitors such that a potential difference across each of the at least some of the plurality of capacitors becomes equal to or more than a voltage lower limit set value. The control unit is configured to start the switching after charging by the charging unit is completed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The invention disclosed in this specification relates to a control circuit, a switched capacitor converter, and a vehicle.

Background Art

[0002] Conventionally, a switched capacitor converter has been used as a power source (see, for example, Patent Document 1).

[0003] A switched capacitor converter has a plurality of switching element connection nodes, and is configured to appropriately connect capacitors between the connection nodes, and performs DC / DC conversion of an input voltage to generate an output voltage.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a switched capacitor converter, which is a type of power source, it is desired to have a short startup time.

Means for Solving the Problems

[0006] The control circuit disclosed in this specification is a control circuit of a switched capacitor converter having a plurality of capacitors and a plurality of switching elements. The control circuit includes a control unit configured to control the switching of the plurality of switching elements, and a charging unit configured to charge at least some of the plurality of capacitors so that the potential difference across both ends becomes equal to or greater than a voltage lower limit set value. The control unit is configured to start the switching after the charging by the charging unit is completed.

[0007] A switched-capacitor converter disclosed herein comprises a control circuit having the above configuration, the plurality of capacitors, and the plurality of switching elements.

[0008] The vehicles disclosed herein have a switched-capacitor converter with the above configuration. [Effects of the Invention]

[0009] According to the inventions disclosed herein, the startup time of a switched-capacitor converter can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 shows a comparative example of a switched-capacitor converter. [Figure 2] Figure 2 is a timing chart showing the voltages at various points in the switched-capacitor converter shown in Figure 1. [Figure 3] Figure 3 shows an embodiment of a switched-capacitor converter. [Figure 4] Figure 4 shows an example of the configuration of the charging and discharging unit. [Figure 5] Figure 5 is a timing chart showing the conditions under which no inrush current occurs at the start of switching. [Figure 6] Figure 6 shows a specific example of the charging and discharging unit shown in Figure 4. [Figure 7] Figure 7 shows an example configuration of a reference voltage generation circuit. [Figure 8] Figure 8 shows an example configuration of a constant current source. [Figure 9] Figure 9 shows an example configuration of a window comparator. [Figure 10] Figure 10 is an external view of the vehicle. [Figure 11] Figure 11 shows the first example of a switched-capacitor converter, which has a different topology from the Dixon type. [Figure 12] FIG. 12 is a diagram showing a second example of a switched capacitor converter having a topology different from the Dickson type. [Figure 13] FIG. 13 is a diagram showing a third example of a switched capacitor converter having a topology different from the Dickson type. [Figure 14] FIG. 14 is a diagram showing a fourth example of a switched capacitor converter having a topology different from the Dickson type. BEST MODE FOR CARRYING OUT THE INVENTION

[0011] In this specification, a MOS (Metal Oxide Semiconductor) field effect transistor refers to a field effect transistor whose gate structure consists of at least three layers of "a layer made of a conductor or a semiconductor such as polysilicon having a small resistance value", "an insulating layer", and "a P-type, N-type, or intrinsic semiconductor layer". That is, the gate structure of a MOS field effect transistor is not limited to a three-layer structure of metal, oxide, and semiconductor.

[0012] In this specification, a constant voltage means a voltage that is constant in an ideal state, and is actually a voltage that can vary slightly due to temperature changes or the like.

[0013] In this specification, a constant current means a current that is constant in an ideal state, and is actually a current that can vary slightly due to temperature changes or the like. Furthermore, the "first constant current" described in paragraph 0034, etc. of this specification corresponds to the "second constant current" described in the claims, the "second constant current" described in paragraph 0034, etc. of this specification corresponds to the "third constant current" described in the claims, and the "third constant current" described in paragraph 0091 of this specification corresponds to the "first constant current" described in the claims.

[0014] <Switched Capacitor Converter (Comparative Example)> FIG. 1 is a diagram showing a comparative example of a switched capacitor converter (= a general configuration compared with the embodiments described later). The topology of the switched capacitor converter SCC1 of this comparative example is the Dickson type topology. FIG. 2 is a timing chart showing the voltages and the like of each part of the switched capacitor converter SCC1.

[0015] The switched capacitor converter SCC1 includes switching elements M1 to M8, capacitors C1 to C3, an output capacitor Cout, and a control unit CNT1.

[0016] The first terminal of the switching element M1 is connected to the positive electrode of the DC voltage source VS1. The negative electrode of the DC voltage source VS1 is connected to the ground potential. The DC voltage source VS1 supplies an input voltage Vin to the first terminal of the switching element M1.

[0017] The second terminal of the switching element M1 is connected to the first terminal of the switching element M2 and the first terminal of the capacitor C3. The second terminal of the switching element M2 is connected to the first terminal of the switching element M3 and the first terminal of the capacitor C2. The second terminal of the switching element M3 is connected to the first terminal of the switching element M4 and the first terminal of the capacitor C1.

[0018] The second terminal of the switching element M4 is connected to the first terminal of the switching element M7, the first terminal of the load LD1, the first terminal of the switching element M6, and the first terminal of the output capacitor Cout. The second terminal of the switching element M7 is connected to the first terminal of the switching element M8, the second terminal of the capacitor C1, and the second terminal of the capacitor C3. The second terminal of the switching element M6 is connected to the first terminal of the switching element M5 and the second terminal of the capacitor C2. The second terminals of the switching element M8, the load LD1, the switching element M5, and the output capacitor Cout are connected to the ground potential.

[0019] The control unit CNT1 controls the switching elements M1, M3, M5, and M7 by the first control signal Φ1 and controls the switching elements M2, M4, M6, and M8 by the second control signal Φ2.

[0020] The control unit CNT1 performs complementary on / off control of the switching elements M1, M3, M5, and M7 and the switching elements M2, M4, M6, and M8.

[0021] The switching voltage VSW1 switches between the value of Vin and the value of Vin × 3 / 4. The switching voltage VSW1 is generated at the connection node N1 between switching element M1 and switching element M2.

[0022] The switching voltage VSW2 switches between a value of Vin × 3 / 4 and a value of Vin / 2. The switching voltage VSW2 is generated at the connection node N2 between switching element M2 and switching element M3.

[0023] The switching voltage VSW3 switches between the values ​​of Vin / 2 and Vin / 4. The switching voltage VSW3 is generated at the connection node N3 between switching element M3 and switching element M4.

[0024] The switching voltage VSW6 switches between the value of Vin / 4 and 0 (ground potential). The switching voltage VSW6 is generated at the connection node between switching element M5 and switching element M6.

[0025] The switching voltage VSW7 switches between the value of Vin / 4 and 0 (ground potential). The switching voltage VSW7 is generated at the connection node between switching element M7 and switching element M8.

[0026] The output voltage Vout is equal to Vin / 4. The output voltage Vout is generated at the connection node Nout between switching elements M4, M6, and M7. The output voltage Vout is supplied to the load LD1.

[0027] Here, we consider the case where the switched capacitor converter SCC1 starts up when capacitors C1 to C3 and the output capacitor Cout have not stored any charge. When the switched capacitor converter SCC1 starts up, if the DC voltage source VS1 raises the input voltage Vin sharply, a large inrush current will flow through the switched capacitor converter SCC1.

[0028] For example, when the DC voltage source VS1 rapidly raises the input voltage Vin from 0V to 48V, and capacitors C1~C3 and output capacitor Cout have not stored any charge, and the input voltage Vin has reached 48V, the control unit CNT1 starts switching control of switching elements M1~M8. In this case, when switching elements M1, M3, M5, and M7 turn on, an inrush current IRUSH (=48 / (R_M1+R_M7)) flows through switching elements M1 and M7 to capacitor C3 and output capacitor Cout. If the resistance value R_M1 of switching element M1 and the resistance value R_M7 of switching element M7 in the ON state are both 0.1Ω, the inrush current IRUSH can reach 480A.

[0029] Since such excessive inrush currents are unacceptable, the control unit CNT1 controls the switching of switching elements M1 to M8, causing the input voltage Vin to rise slowly from 0V to 48V, thereby suppressing the inrush current (IRUSH). As a result, the switched-capacitor converter SCC1 cannot shorten its startup time.

[0030] In light of the above considerations, we propose a novel embodiment below that can shorten the startup time compared to the comparative example.

[0031] <Switched Capacitor Converter (Embodiment)> Figure 3 shows an embodiment of the switched capacitor converter. The switched capacitor converter SCC2 of this embodiment differs from the switched capacitor converter SCC1 described above in that it has a charge / discharge unit 1, but is otherwise basically the same as the switched capacitor converter SCC1 described above.

[0032] The switched-capacitor converter SCC2 has a control circuit 2. The control circuit 2 includes a control unit CNT1 and a charge / discharge unit 1.

[0033] The charging / discharging unit 1 is supplied with an input voltage Vin, switching voltages VSW1 to VSW3, output voltage Vout, and ground potential. The charging / discharging unit 1 charges and discharges capacitors C1 to C3 and output capacitor Cout when the switched capacitor converter SCC2 is started.

[0034] Figure 4 shows an example configuration of the charge / discharge unit 1. The charge / discharge unit 1 in the example configuration shown in Figure 4 includes constant current sources IS1A to IS4A and IS1B to IS4B, switches SW1 to SW4, and a switch control unit 11. Constant current sources IS1A to IS4A are current sources that output a first constant current. Constant current sources IS1B to IS4B are current sources that output a second constant current. The first constant current and the second constant current may have the same current value, or they may have different current values.

[0035] An input voltage Vin is applied to the first terminal of each of the constant current sources IS1A to IS4A. Switches SW1 to SW4 are controlled by the switch control unit 11 to enter one of the first to third states.

[0036] When switch SW1 is in the first state, switch SW1 electrically connects the second terminal of constant current source IS1A to connection node N1. When switch SW1 is in the second state, switch SW1 electrically connects the first terminal of constant current source IS1B to connection node N1. When switch SW1 is in the third state, switch SW1 electrically disconnects the second terminal of constant current source IS1A and the first terminal of constant current source IS1B from connection node N1.

[0037] When switch SW2 is in the first state, switch SW2 electrically connects the second terminal of constant current source IS2A to connection node N2. When switch SW2 is in the second state, switch SW2 electrically connects the first terminal of constant current source IS2B to connection node N2. When switch SW2 is in the third state, switch SW2 electrically disconnects the second terminal of constant current source IS2A and the first terminal of constant current source IS2B from connection node N2.

[0038] When switch SW3 is in the first state, switch SW3 electrically connects the second terminal of constant current source IS3A to connection node N3. When switch SW3 is in the second state, switch SW3 electrically connects the first terminal of constant current source IS3B to connection node N3. When switch SW3 is in the third state, switch SW3 electrically disconnects the second terminal of constant current source IS3A and the first terminal of constant current source IS3B from connection node N3.

[0039] When switch SW4 is in the first state, switch SW4 electrically connects the second terminal of constant current source IS4A to connection node N4. When switch SW4 is in the second state, switch SW4 electrically connects the first terminal of constant current source IS4B to connection node N4. When switch SW4 is in the third state, switch SW4 electrically disconnects the second terminal of constant current source IS4A and the first terminal of constant current source IS4B from connection node N4.

[0040] Ground potential is applied to the second terminals of each of the constant current sources IS1B to IS4B.

[0041] Figure 5 is a timing chart showing the conditions under which no inrush current occurs at the start of switching of the switched-capacitor converter SCC2. The horizontal axis of Figure 5 represents time, and the vertical axis represents voltage.

[0042] When the switched-capacitor converter SCC2 starts up, the input voltage Vin rises steeply from 0V to a predetermined value (e.g., 48V). After the input voltage Vin reaches the predetermined value, the control unit CNT1 turns on the switching elements M5 and M8, and the charge / discharge unit 1 charges capacitors C1 to C3 and the output capacitor Cout with a first constant current. When the output voltage Vout (potential difference across the output capacitor Cout) reaches Vin / 4, the charge / discharge unit 1 stops charging the output capacitor Cout. When the switching voltage VSW3 (potential difference across the capacitor C1) reaches Vin / 4, the charge / discharge unit 1 stops charging the capacitor C1. When the switching voltage VSW2 (potential difference across the capacitor C2) reaches Vin × 2 / 4, the charge / discharge unit 1 stops charging the capacitor C2. When the switching voltage VSW1 (potential difference across the capacitor C3) reaches Vin × 3 / 4, the charge / discharge unit 1 stops charging the capacitor C3.

[0043] At timing TM1, when charging of capacitors C1-C3 and output capacitor Cout has stopped, the control unit CNT1 starts switching control of switching elements M1-M8. This prevents inrush current from occurring when the switched-capacitor converter SCC2 starts switching.

[0044] Considering that there are manufacturing variations in the capacitances of capacitors C1 to C3 and output capacitor Cout, that it is not necessary to suppress the inrush current to zero, and that capacitors C1 to C3 and output capacitor Cout may be overcharged due to the effects of leakage current of switching elements M1 to M8, it is desirable that the timing at which the control unit CNT1 starts switching control of switching elements M1 to M8 is, for example, the following first condition.

[0045] The first condition is that the output voltage Vout (potential difference across output capacitor Cout) and the switching voltage VSW3 (potential difference across capacitor C1) are between Vin / 4-ΔV and Vin / 4+ΔV, the switching voltage VSW2 (potential difference across capacitor C2) is between Vin×2 / 4-ΔV and Vin×2 / 4+ΔV, and the switching voltage VSW1 (potential difference across capacitor C3) is between Vin×3 / 4-ΔV and Vin×3 / 4+ΔV.

[0046] In order to set the timing at which the control unit CNT1 starts switching control of the switching elements M1 to M8 to the above first condition, it is desirable that the charge / discharge unit 1 has the configuration shown in Figure 6, which is a specific example of the configuration shown in Figure 4, and that the switch control unit 11 has the reference voltage generation circuit shown in Figure 7 and the four window comparators shown in Figure 9.

[0047] The switch SWkA (where k is a natural number between 1 and 4) provided in the charging / discharging unit 1 with the configuration shown in Figure 6 turns on when the control signal SkA is at a HIGH level and turns off when the control signal SkA is at a LOW level. Similarly, the switch SWkB provided in the charging / discharging unit 1 with the configuration shown in Figure 6 turns on when the control signal SkB is at a HIGH level and turns off when the control signal SkB is at a LOW level.

[0048] The reference voltage generation circuit shown in Figure 7 includes resistors R1 to R8, an operational amplifier OP1, P-channel MOS field-effect transistors Q1 to Q3, N-channel MOS field-effect transistors Q4 and Q5, and a constant current source IS5. For the power supply voltage VCC of the reference voltage generation circuit shown in Figure 7, the input voltage Vin can be used, for example.

[0049] A resistor voltage divider circuit, composed of resistors R1 and R2, divides the input voltage Vin to generate a voltage with the value Vin / (4N). The value of N is adjusted by the respective resistance values ​​of resistors R1 and R2. The Vin / (4N) voltage output from this resistor voltage divider circuit is supplied to the non-inverting input terminal of operational amplifier OP1. The output terminal of operational amplifier OP1 is connected to the inverting input terminal of operational amplifier OP1. As a result, operational amplifier OP1 operates as a buffer amplifier.

[0050] The voltage Vin / (4N) output from op-amp OP1 is supplied to the series circuit of resistors R3 to R8. Specifically, the voltage Vin / (4N) output from op-amp OP1 is supplied to the connection node between resistors R5 and R6.

[0051] The first and second current mirror circuits supply a current corresponding to the constant current Ib output from the constant current source IS5 to a series circuit of resistors R3 to R8. The first current mirror circuit is composed of MOS field-effect transistors Q1 to Q3. The second current mirror circuit is composed of MOS field-effect transistors Q4 and Q5.

[0052] The first reference voltage for the value Vin / (4N)+ΔV / N is output from the connection node between MOS field-effect transistor Q3 and resistor R3. The second reference voltage for the value Vin / (4N)+ΔV / (2N) is output from the connection node between resistor R3 and resistor R4. The third reference voltage for the value Vin / (4N)+ΔV / (3N) is output from the connection node between resistor R4 and resistor R5. The fourth reference voltage for the value Vin / (4N)-ΔV / (3N) is output from the connection node between resistor R6 and resistor R7. The fifth reference voltage for the value Vin / (4N)-ΔV / (2N) is output from the connection node between resistor R7 and resistor R8. The sixth reference voltage for the value Vin / (4N)-ΔV / N is output from the connection node between resistor R8 and MOS field-effect transistor Q5. The values ​​of the first to third reference voltages are the upper voltage setting values, and the values ​​of the fourth to sixth reference voltages are the lower voltage setting values.

[0053] Here, by configuring the constant current source IS5 as shown in Figure 8, the accuracy of the values ​​of the first to sixth reference voltages can be improved. The constant current source IS5 in the configuration shown in Figure 8 includes an operational amplifier OP2, an N-channel MOS field-effect transistor Q6, and a resistor R9.

[0054] A constant voltage Vb is supplied to the non-inverting input terminal of the operational amplifier OP2. The constant voltage Vb is a high-precision constant voltage, such as a bandgap reference voltage. The output terminal of the operational amplifier OP2 is connected to the gate of the MOS field-effect transistor Q6. The inverting input terminal of the operational amplifier OP2 is connected to the source of the MOS field-effect transistor Q6 and the first terminal of resistor R9. The second terminal of resistor R9 is connected to ground potential.

[0055] The value of the constant current Ib output from the constant current source IS5 in the configuration shown in Figure 8 can be expressed by the following equation (1). In equation (1) below, Ib is the value of the constant current Ib, Vb is the value of the constant voltage Vb, and R9 is the resistance value of resistor R9. Ib = Vb / R9 …(1)

[0056] If we let R be the resistance value of resistors R3 to R8, then the above ΔV can be expressed by equation (2) below. Therefore, by matching the characteristics of resistor R9 and resistors R3 to R8, the accuracy of the above ΔV is improved, and thus the accuracy of the values ​​of the 1st to 6th reference voltages is improved. For example, by forming resistors R9 and R3 to R8 using the same manufacturing process, the characteristics of resistors R9 and R3 to R8 can be matched. ΔV = Vb × R / R⁹ …(2)

[0057] The four window comparators Wk shown in Figure 9 (where k is a natural number between 1 and 4) output control signals SkA and SkB.

[0058] The window comparator W1 includes resistors R10 and R11, comparators COMP1 and COMP2, a NOR gate NOR1, and an AND gate AND1.

[0059] The window comparator W2 includes resistors R12 and R13, comparators COMP3 and COMP4, a NOR gate NOR2, and an AND gate AND2.

[0060] The window comparator W3 includes resistors R14 and R15, comparators COMP5 and COMP6, a NOR gate NOR3, and an AND gate AND3.

[0061] The window comparator W4 includes resistors R16 and R17, comparators COMP7 and COMP8, a NOR gate NOR4, and an AND gate AND4.

[0062] Since the four window comparators W1 to W4 have basically the same circuit configuration, we will describe the circuit configuration of window comparator W1 as an example.

[0063] A resistive voltage divider circuit, composed of resistors R1 and R2, divides the input voltage Vin to generate a voltage with a value of Vin / (4N). The value of N is adjusted by the respective resistance values ​​of resistors R1 and R2. The Vin / (4N) voltage output from this resistive voltage divider circuit is supplied to the non-inverting input terminals of comparators COMP1 and COMP2. A third reference voltage with a value of Vin / (4N) + ΔV / (3N) is supplied to the inverting input terminal of comparator COMP1. A fourth reference voltage with a value of Vin / (4N) - ΔV / (3N) is supplied to the inverting input terminal of comparator COMP2.

[0064] The NOR gate NOR1 outputs a control signal S1A, which is the negative OR of the outputs of comparator COMP1 and comparator COMP2.

[0065] The AND gate AND1 outputs a control signal S1B, which is the logical AND of the output of comparator COMP1 and the output of comparator COMP2.

[0066] <Examples of application> Figure 10 is an external view of vehicle X. In this example configuration, vehicle X is equipped with various electronic devices X11 to X18 that operate using voltage supplied from a battery (not shown). Note that the mounting positions of the electronic devices X11 to X18 in this figure may differ from those in reality for illustrative purposes.

[0067] Electronic device X11 is an engine control unit that performs engine-related controls (such as injection control, electronic throttle control, idle control, oxygen sensor heater control, and auto cruise control).

[0068] Electronic device X12 is a lamp control unit that controls the on / off state of lights such as HID (high-intensity discharged lamps) and DRL (daytime running lamps).

[0069] Electronic device X13 is a transmission control unit that performs control related to the transmission.

[0070] The electronic device X14 is a braking unit that performs control related to the motion of the vehicle X (such as ABS [anti-lock brake system] control, EPS [electric power steering] control, and electronic suspension control).

[0071] Electronic device X15 is a security control unit that controls the operation of door locks, burglary alarms, and other devices.

[0072] Electronic equipment X16 consists of electronic components that are installed in vehicle X at the factory as standard equipment or manufacturer options, including wipers, power door mirrors, power windows, dampers (shock absorbers), power sunroof, and power seats.

[0073] Electronic equipment X17 is an electronic device that can be optionally installed in vehicle X as a user option, such as an in-vehicle A / V (audio / visual) device, a car navigation system, and an ETC (electronic toll collection system).

[0074] Electronic equipment X18 is a type of electronic equipment equipped with high-voltage motors, such as automotive blowers, oil pumps, water pumps, and battery cooling fans.

[0075] Furthermore, the switched-capacitor converter SCC2 described above can be incorporated into any of the electronic devices X11 to X18. Also, the applications of the switched-capacitor converter SCC2 are not limited to power supplies installed in vehicles X; for example, they could also be used as power supplies in industrial equipment.

[0076] <Other> The structure of the invention can be modified in various ways, in addition to the embodiments described above, without departing from the spirit of the invention. The embodiments described above should be considered in all respects to be illustrative and not restrictive, and the technical scope of the present invention is indicated by the claims, not by the description of the embodiments described above, and should be understood to include all modifications that fall within the meaning and scope equivalent to the claims.

[0077] For example, in a switched capacitor converter SCC2, the arrangement of the DC voltage source VS1 and the load LD1 may be swapped. When the arrangement of the DC voltage source VS1 and the load LD1 is swapped, the voltage supplied from the switched capacitor converter SCC2 to the load LD1 (the output voltage of the switched capacitor converter SCC2) becomes greater than the voltage supplied from the DC voltage source VS1 to the switched capacitor converter SCC2 (the input voltage of the switched capacitor converter SCC2).

[0078] The control circuit 2 described above can also be applied to switched-capacitor converters, which have a different topology from the Dixon type. Examples of switched-capacitor converters with a different topology from the Dixon type include the switched-capacitor converters shown in Figures 11 to 14.

[0079] Although the control circuit 2 described above had a charging / discharging unit 1, it may also have a charging unit instead of the charging / discharging unit 1. In other words, the control circuit 2 may have no discharging unit.

[0080] The control circuit 2 described above allows charging and discharging of all capacitors C1 to C3 of the switched capacitor converter SCC2 before switching of the switching elements M1 to M8. However, it is also possible to allow charging and discharging of only some of the capacitors C1 to C3 of the switched capacitor converter SCC2 before switching of the switching elements M1 to M8. Even when charging and discharging is possible for only some of the capacitors C1 to C3, the startup time of the switched capacitor converter SCC2 can be shortened, although the effect is reduced compared to when charging and discharging is possible for all of the capacitors C1 to C3.

[0081] The control circuit (2) described above is a control circuit for a switched capacitor converter (SCC2) having a plurality of capacitors (C1 to C3) and a plurality of switching elements (M1 to M8), and comprises a control unit (CNT1) configured to control the switching of the plurality of switching elements, and a charging unit (1) configured to charge at least a portion of the plurality of capacitors to a voltage lower limit setting value or higher, wherein the control unit is configured to start the switching after the charging by the charging unit is completed (first configuration).

[0082] The control circuit of the first configuration described above can shorten the startup time of the switched-capacitor converter.

[0083] In the control circuit of the first configuration described above, the charging unit may be configured such that charging begins only after at least one end of the plurality of capacitors is electrically connected to ground potential (second configuration).

[0084] The control circuit of the second configuration described above can reliably charge at least some of the multiple capacitors.

[0085] In the control circuit of the first or second configuration described above, the charging unit may be configured to charge with a first constant current (third configuration).

[0086] The control circuit in the third configuration described above makes it easier to limit the inrush current during charging.

[0087] In a control circuit according to any of the first to third configurations described above, there may also be a configuration (fourth configuration) that includes a discharge section (1) configured to discharge at least a portion of the plurality of capacitors such that the potential difference across them becomes less than or equal to a set voltage upper limit.

[0088] The control circuit of the fourth configuration described above can eliminate the condition in which at least some of the multiple capacitors are overcharged due to the influence of leakage current of the switching element, etc.

[0089] In the control circuit of the fourth configuration described above, the discharge unit may be configured to discharge with a second constant current (fifth configuration).

[0090] The control circuit of the fifth configuration described above makes it easier to limit the inrush current during discharge.

[0091] In the control circuits of the first to fifth configurations described above, there may also be a sixth configuration which includes a constant current source (IS5) that includes a first resistor (R9) and is configured to output a third constant current flowing through the first resistor by applying a constant voltage to the first resistor, and second resistors (R6 to R8) configured to supply a current corresponding to the third constant current, wherein the voltage lower limit setting value is determined by the voltage output from the ends of the second resistors.

[0092] The control circuit of the seventh configuration described above can improve the accuracy of the voltage lower limit setting by matching the characteristics of the first resistor and the second resistor.

[0093] The switched-capacitor converter (SCC2) described above has a configuration (the seventh configuration) comprising a control circuit according to any of the first to sixth configurations described above, the plurality of capacitors, and the plurality of switching elements.

[0094] The seventh configuration of the switched-capacitor converter described above can reduce the startup time.

[0095] The vehicle (X) described above has a configuration (8th configuration) that includes a switched capacitor converter as described in the 7th configuration above.

[0096] The vehicle with the eighth configuration described above can reduce the startup time of the switched-capacitor converter. [Explanation of Symbols]

[0097] 1 Charge / discharge section 2 Control circuits 11 Switch control unit AND1~AND4 ANDGATE C1~C3 Capacitors Cout output capacitor CNT1 Control Unit COMP1~COMP8 Comparators IS1A~IS4A, IS1B~IS4B, IS5 constant current source LD1 load M1~M8 Switching Elements N1~N4 Connection Nodes NOR1~NOR4 NORGATE OP1~OP2 Operational Amplifiers Q1-Q6 MOS field-effect transistors R1~R17 Resistors SCC1, SCC2 Switched Capacitor Converters SW1~SW4 Switches VS1 DC voltage source W1~W4 Window Comparator X Vehicle X11~X18 Electronic equipment

Claims

1. Multiple capacitors, A control circuit for a switched-capacitor converter having a plurality of switching elements, A control unit configured to control the switching of the plurality of switching elements, A charging unit configured to charge at least some of the plurality of capacitors such that the potential difference across them is equal to or greater than a set lower voltage limit, A constant current source including a first resistor, configured to output a first constant current flowing through the first resistor by applying a constant voltage to the first resistor, A second resistor configured to supply a current corresponding to the first constant current, It has, The control unit is configured to start the switching after charging by the charging unit is completed. A control circuit in which the voltage lower limit setting value is determined by the voltage output from the terminal of the second resistor.

2. The control circuit according to claim 1, wherein the charging unit is configured to start charging after at least one end of the plurality of capacitors is electrically connected to the ground potential.

3. The control circuit according to claim 1, wherein the charging unit is configured to charge with a second constant current.

4. The control circuit according to claim 1, further comprising a discharge unit configured to discharge at least a portion of the plurality of capacitors such that the potential difference across them is less than or equal to a set voltage limit.

5. The control circuit according to claim 4, wherein the discharge unit is configured to discharge with a third constant current.

6. A control circuit according to any one of claims 1 to 5, The aforementioned plurality of capacitors, A switched-capacitor converter having the aforementioned plurality of switching elements.

7. A vehicle having the switched capacitor converter described in claim 6.

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