DC / DC converter to which flying capacitor is applied and method for controlling DC / DC converter
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-01-09
- Publication Date
- 2026-08-13
Smart Images
Figure KR2026000548_13082026_PF_FP_ABST
Abstract
Description
DC / DC converter with flying capacitor and control method of the DC / DC converter
[0001] The present invention relates to a DC / DC converter to which a flying capacitor is applied.
[0002] As electronic devices become increasingly sophisticated, devices capable of performing a wider variety of functions in a shorter amount of time are emerging. These devices are required to process more than one function simultaneously at a faster speed. Consequently, electronic devices requiring higher operating voltages are appearing.
[0003] On the other hand, since providing the operating voltage required by each electronic device is inefficient, a DC / DC converter, such as a multi-level converter, is typically used to sequentially convert a DC current of a preset voltage into a DC current of the higher voltage required by the electronic device. As such, multi-level converters can utilize switches that operate at low voltages, making them more advantageous in terms of cost.
[0004] However, when converting a low-voltage current into a high-voltage DC current through switch control, if this is controlled by only a single switch, a high voltage is formed across that switch, which can cause the switch to degrade rapidly. Accordingly, by connecting multiple switches in parallel instead of a single switch, the high voltage formed during the voltage conversion is distributed to each switch, thereby preventing degradation of each switch caused by the high voltage. Additionally, by distributing the voltage applied to the switches, there is an advantage in that a higher input / output voltage relative to the switch voltage can be used. Furthermore, the current ripple frequency of the inductor may increase depending on the number of switches connected in parallel. For example, if two switches are connected in parallel, the current ripple frequency can increase twofold relative to the switching frequency. Therefore, there is an advantage in that a smaller-sized inductor design is possible.
[0005] Meanwhile, since the aforementioned multiple switches are arranged in parallel for high-voltage distribution, there is a problem that they must operate simultaneously during voltage conversion. However, since it is practically impossible for the multiple switches to operate completely simultaneously, a capacitor can be placed between the multiple switches to mitigate voltage fluctuations caused by differences in the operating times of the multiple switches. In this case, the capacitor is connected in a floating form, separated from the ground (GND) in the middle of the switch terminals, and can be named a flying capacitor.
[0006] When flying capacitors are arranged in this manner, in order to ensure that voltages are accurately distributed to each switch, the output voltage of the DC / DC converter must be maintained at a voltage distributed according to the number of flying capacitors. For example, if the plurality of switches are formed as two and a single flying capacitor is placed between the two switches, half of the output voltage (V0) of the DC / DC converter must be maintained at the flying capacitor to ensure that the voltage is evenly distributed to the two switches. And the voltage (V) of the flying capacitor F The voltage can be distributed evenly to the two switches only when ) maintains half of the output voltage (V0) of the DC / DC converter.
[0007] However, in the case of a flying capacitor, the voltage (V) changes over time F ) may change. For example, as time passes, the voltage (V) of the flying capacitor above through natural discharge F ) can be reduced. In this way, the voltage (V) of the flying capacitor can be reduced. F Since ) can vary, a conventional DC / DC converter uses the voltage (V) of the flying capacitor mentioned above. F) can be maintained at a constant level according to a preset voltage based on the output voltage (V0) of the above DC / DC converter.
[0008] Meanwhile, in the case of a conventional DC / DC converter having the plurality of switches mentioned above, the voltage (V) of the flying capacitor is controlled according to the duty ratio of the switches. F ) can be increased or decreased. However, in the case where no load is connected, the above-mentioned conventional DC / DC converter determines the on / off of each switch based on a carrier signal having the same amplitude in the positive or negative direction relative to the state where the current is zero. Therefore, the voltage (V) of the flying capacitor controlled according to the switch signal is F Since ) decreases by the same amount as it increased according to switch control, the voltage of the flying capacitor (V F There is a problem that the change in ) becomes zero. Therefore, in the no-load state, a typical DC / DC converter [uses] the voltage (V of the flying capacitor mentioned above). F There is a problem that it is impossible to control.
[0009] The present invention aims to solve the aforementioned problems and other problems by providing a DC / DC converter capable of voltage control of a flying capacitor even in a no-load state, and a method for controlling the DC / DC converter.
[0010] In addition, the present invention provides a DC / DC converter capable of determining whether it is in a loaded state or an unloaded state based on the detected current, and a method for controlling the DC / DC converter capable of controlling the voltage of a flying capacitor in different ways depending on the determined state.
[0011] According to one aspect of the present invention for achieving the above or other purposes, a DC / DC converter comprising a plurality of switches in which output voltage is evenly distributed according to an embodiment of the present invention and at least one flying capacitor disposed between the plurality of switches comprises: a current detection unit for detecting a current flowing in an internal circuit of the DC / DC converter; a voltage detection unit for detecting the voltage of the flying capacitor and the output voltage of the DC / DC converter; and a control unit for controlling the voltage of the flying capacitor in any one of a first method for controlling the driving time of at least one of a first switch in which the voltage of the flying capacitor rises when the plurality of switches are turned on and a second switch in which the voltage of the flying capacitor falls when the switch is turned off, according to the detection result of the current detection unit, or a second method for delaying the phase of at least one of a first carrier signal for generating a switch signal for determining the switch duty ratio of the first switch or a second carrier signal for generating a switch signal for determining the switch duty ratio of the second switch.
[0012] In one embodiment, the control unit checks whether a load is connected to the DC / DC converter based on whether the current flowing in the internal circuit of the DC / DC converter is within a range where it can be considered as 0 or 0 based on the detection result of the current detection unit, and controls the voltage of the flying capacitor in either the first method or the second method based on the load check result.
[0013] In one embodiment, the control unit is characterized by initializing the phase delay time of the first carrier signal and the second carrier signal when controlling the voltage of the flying capacitor according to the first method.
[0014] In one embodiment, the control unit determines a target voltage of the flying capacitor according to the output voltage and the number of switches provided in the plurality of switches, and determines the driving time of the at least one switch or the phase delay time of the at least one carrier signal according to the difference between the determined target voltage and the voltage of the detected flying capacitor.
[0015] In one embodiment, the carrier signal is a signal in the form of a triangular wave having a constant frequency that oscillates periodically between a negative voltage and a positive voltage having a constant value, and the switch signal is formed according to the carrier signal and a preset modulation voltage, and is characterized in that the ratio of the time a specific switch is turned on and the time it is turned off is determined differently depending on the magnitude of the modulation voltage.
[0016] In one embodiment, the control unit is characterized by delaying the phase of at least one of a carrier signal corresponding to one switch and a carrier signal corresponding to another switch so that a first time interval between the time when one switch is turned off and the time when another switch is turned on, and a second time interval between the time when the other switch is turned off and the time when one switch is turned on are different from each other.
[0017] In one embodiment, the control unit is characterized in that the first time interval and the second time interval are changed in opposite ways.
[0018] In one embodiment, the plurality of switches includes a plurality of complementary switches that switch complementarily to each of the plurality of switches, and the flying capacitor is characterized by being disposed between the plurality of switches and between the plurality of complementary switches.
[0019] According to one aspect of the present invention for achieving the above or other purposes, a control method for a DC / DC converter according to an embodiment of the present invention comprises: a step of detecting a current flowing in an internal circuit of the DC / DC converter; a step of detecting a voltage of a flying capacitor and an output voltage of the DC / DC converter; a step of, when the detection result of the current detection unit determines that a load is connected to the DC / DC converter, controlling the voltage of the flying capacitor according to a first method of controlling the driving time of at least one of a first switch in which the voltage of the flying capacitor rises when turned on among a plurality of switches and a second switch in which the voltage of the flying capacitor falls when turned off; and a step of, when the current detection result determines that a load is not connected to the DC / DC converter, controlling the voltage of the flying capacitor according to a second method of delaying the phase of at least one of a first carrier signal for generating a switch signal for determining the switch duty ratio of the first switch or a second carrier signal for generating a switch signal for determining the switch duty ratio of the second switch. It is characterized by.
[0020] In one embodiment, the step of detecting the current flowing in the internal circuit of the DC / DC converter is characterized by determining that a load is connected to the DC / DC converter when the current flowing in the internal circuit of the DC / DC converter is zero or within a range that can be considered zero, and determining that a load is not connected to the DC / DC converter when the current flowing in the internal circuit of the DC / DC converter has a positive or negative value exceeding the range that can be considered zero.
[0021] In one embodiment, the step of detecting the voltage of the flying capacitor and the output voltage of the DC / DC converter further comprises the step of determining the target voltage of the flying capacitor according to the output voltage and the number of switches provided in the plurality of switches, and the step of calculating the difference between the target voltage and the detected voltage of the flying capacitor and determining the direction to control the voltage of the flying capacitor according to the calculated voltage difference.
[0022] In one embodiment, the step of controlling the voltage of the flying capacitor according to the first method comprises: determining a switch corresponding to the first switch and a switch corresponding to the second switch based on whether the current flowing through the internal circuit of the DC / DC converter has a positive value or a negative value; determining a switch among the first switch and the second switch to control the driving time according to the determined voltage control direction; determining the length of the driving time to be controlled according to the difference between the target voltage and the detected voltage of the flying capacitor; and controlling at least one on and off of the switch among the switch corresponding to the first switch and the switch corresponding to the second switch to be controlled according to the control length of the determined driving time.
[0023] In one embodiment, the step of controlling the voltage of the flying capacitor according to the first method is characterized by including the step of initializing the phase delay time of the first carrier signal and the second carrier signal when controlling the voltage of the flying capacitor according to the first method.
[0024] In one embodiment, the step of controlling the voltage of the flying capacitor according to the first method comprises: determining a switch corresponding to the first switch and a switch corresponding to the second switch in a no-load state; determining at least one of the first carrier signal and the second carrier signal to delay the phase according to the difference between the target voltage and the detected flying capacitor voltage according to the determined voltage control direction; determining the phase delay value to be delayed according to the difference between the target voltage and the detected flying capacitor voltage; and delaying the at least one of the first carrier signal and the second carrier signal according to the determined phase delay value and generating at least one switch signal according to the at least one carrier signal with the delayed phase.
[0025] In one embodiment, the step of generating a switch signal according to the phase-delayed carrier signal is characterized by generating a switch signal for determining the duty ratio of one switch and a switch signal for determining the duty ratio of another switch, wherein, due to the phase delay, the first time interval between the time when one switch is turned off and the time when another switch is turned on and the second time interval between the time when the other switch is turned off and the time when one switch is turned on are different.
[0026] According to at least one embodiment of the present invention, when in a no-load state, the voltage (V) of a flying capacitor F A first carrier signal generating a switch signal for controlling a switch that increases ), and the voltage (V) of the flying capacitor F At least one of the second carrier signals generating a switch signal for controlling a switch that reduces ) is the voltage (V) of the flying capacitor to be controlled. FIt can be delayed depending on ). Therefore, the time interval between switch signals controlled by the carrier signal changes, so the voltage of the flying capacitor (V F ) is made so that the amount of increase and decrease differ depending on the switch control. Accordingly, even in the no-load state, the voltage (V) of the flying capacitor F It has the effect of being able to maintain the voltage at a preset level.
[0027] FIG. 1 is a conceptual diagram illustrating the configuration of a conventional DC / DC converter having a plurality of switches.
[0028] Figure 2 is a conceptual diagram for explaining the voltage change of a flying capacitor according to the state of the switch in the DC / DC converter illustrated in Figure 1.
[0029] Figure 3 is an example diagram showing the change in voltage and current according to the switch operation state when the current flowing through the DC / DC converter of Figure 1 has a positive value.
[0030] Figure 4 is an example diagram showing the change in voltage and current according to the switch operation state when the current flowing through the DC / DC converter of Figure 1 has a negative value.
[0031] FIGS. 5 and FIGS. 6 are example diagrams illustrating cases where the duty ratios of each switch are changed differently when in a no-load state in the DC / DC converter of FIG. 1.
[0032] FIG. 7 is a block diagram illustrating the configuration of a DC / DC converter according to an embodiment of the present invention.
[0033] FIG. 8 is a conceptual diagram illustrating the operation process of a DC / DC converter according to an embodiment of the present invention.
[0034] FIG. 9 is a flowchart illustrating the operation process of a DC / DC converter according to an embodiment of the present invention.
[0035] FIG. 10 shows the voltage (V) of a flying capacitor according to the delay of a carrier signal in a no-load state in a DC / DC converter according to an embodiment of the present invention. F This is an example illustrating an example where the amount of increase and decrease differs.
[0036] It should be noted that technical terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. Additionally, singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be omitted, or that additional components or steps may be included.
[0037] In addition, when describing the technology disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the technology disclosed in this specification, such detailed description is omitted.
[0038] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings.
[0039] Figure 1 illustrates the configuration of a DC / DC converter in which multiple switches are arranged in parallel for voltage distribution.
[0040] Referring to FIG. 1, a multi-level converter (DC / DC converter) may be configured to include a switch that forms a first circuit including an inductor (L) when turned on, and a complementary switch that forms a second circuit including the inductor (L) and an output capacitor (130) when turned on.
[0041] In this case, the complementary switch can be switched complementarily to the switch forming the first circuit. That is, when the switch forming the first circuit is turned on, the complementary switch can be turned off. Conversely, when the switch forming the first circuit is turned off, the complementary switch can be turned on. Additionally, since the voltage flowing through the second circuit reflects the voltage of the output capacitor (V0), it may differ from the voltage flowing through the first circuit, and accordingly, different voltages can be formed depending on the control of the switch.
[0042] Meanwhile, in the case of such a multi-level converter, if only one switch is configured as described above, the voltage may be concentrated on a single switch and degraded. Therefore, the multi-level converter can use multiple switches to distribute the voltage applied to each switch. Accordingly, as shown in FIG. 1, the multi-level converter may be equipped with multiple switches (S1 (101), S2 (102)) and multiple complementary switches (S1' (111), S2' (112)). In this case, among the switches, the first switch (S1 (101)) can operate complementarily with the first complementary switch (S1' (111)), and among the switches, the second switch (S2 (102)) can operate complementarily with the second complementary switch (S2' (112)).
[0043] In this case, when a multi-level converter is configured with multiple switches, a flying capacitor (120) may be placed between the switches, i.e., between the first switch (S1 (101)) and the second switch (S2 (102)), and between the complementary switches, i.e., between the first complementary switch (S1' (111)) and the second complementary switch (S2' (112)). In this case, the voltage (V) of the flying capacitor (120) FWhen the output capacitor (130) maintains half of the output voltage (V0), the output voltage (V0) can be evenly distributed between the switches (101, 102), the complementary switches (111, 112), or between any one of the switches (101, 102) and any one of the complementary switches (111, 112).
[0044] However, as described above, the voltage (V) of the flying capacitor (120) F ) can vary over time. For example, the voltage (V) of the flying capacitor (120) F ) can gradually naturally discharge over time. Therefore, the multi-level converter, the voltage (V) of the flying capacitor (120) F In the case where the number of provided switches is, for example, composed of two switches as shown in FIG. 1, the voltage (V) of the flying capacitor (120) is maintained at a voltage corresponding to half of the output voltage (V0) by controlling either of the switches (101, 102) and either of the complementary switches (111, 112). F It can increase or decrease )
[0045] Figure 2 is a conceptual diagram illustrating the voltage change of a flying capacitor according to the state of each switch in the multi-level DC / DC converter illustrated in Figure 1.
[0046] First, the current flowing through the circuit (i L If ) has a positive value, and both the first and second switches (S1 (101), S2 (102)) are turned on (both the first and second complementary switches (S1' (111), S2' (112)) are turned off), then a first circuit including an inductor (L) can be formed. In this case, the current (I) flowing through the flying capacitor (120) F) can be 0. Also, if both the first and second complementary switches (S1'(111), S2'(112)) are turned on (both first and second switches (S1(101), S2(102)) are off), a second circuit including an inductor (L) and an output capacitor (130) can be formed. In this case, likewise, the current (I) flowing through the flying capacitor (120) F ) can be 0.
[0047] However, if the first switch (S1 (101)) is turned on (the first complementary switch (S1' (111)) is turned off) and the second complementary switch (S2' (112)) is turned on (the second switch (S2 (102)) is turned off), current flowing through the inductor (L) can flow into the flying capacitor (120). Therefore, the voltage (V) of the flying capacitor (120) F ) can be increased. On the other hand, if the first switch (S1 (101)) is turned off (the first complementary switch (S1' (111)) is turned on) and the second complementary switch (S2' (112)) is turned off (the second switch (S2 (102)) is turned on), the current charged in the flying capacitor (120) can flow into the output capacitor (130) through the turned-on second switch (S2 (102)). Therefore, the voltage (V) of the flying capacitor (120) F ) can be reduced.
[0048] Meanwhile, the current flowing through the circuit (i L If ) has a negative value, or if both the first and second switches (S1 (101), S2 (102)) are turned on (if both the first and second complementary switches (S1' (111), S2' (112)) are turned off), a first circuit including an inductor (L) can be formed. In this case, the current (I) flowing through the flying capacitor (120) F) can be 0. Also, if both the first and second complementary switches (S1'(111), S2'(112)) are turned on (if both the first and second switches (S1(101), S2(102)) are turned off), a second circuit including an inductor (L) and an output capacitor (130) can be formed. In this case, likewise, the current (I) flowing through the flying capacitor (120) F ) can be 0.
[0049] However, if the first switch (S1 (101)) is turned on (the first complementary switch (S1' (111)) is turned off) and the second complementary switch (S2' (112)) is turned on (the second switch (S2 (102)) is turned off), the current charged in the flying capacitor (120) can flow into the inductor (L). Therefore, the voltage (V) of the flying capacitor (120) F ) can be reduced. On the other hand, if the first switch (S1 (101)) is turned off (the first complementary switch (S1' (111)) is turned on) and the second complementary switch (S2' (112)) is turned off (the second switch (S2 (102)) is turned on), the current charged in the output capacitor (130) can flow into the flying capacitor (120) through the turned-on second switch (S2 (102)). Therefore, the voltage (V) of the flying capacitor (120) F ) can be increased.
[0050] FIG. 3 shows the current (i) flowing through the DC / DC converter of FIG. 1. L When ) has a positive value, the voltage (V) of the flying capacitor (120) according to the switch operation state F ) and current(I F ) is an example diagram showing the change. And Fig. 4 is a current (i) flowing through the DC / DC converter of Fig. 1. L When ) has a negative value, the voltage (V) of the flying capacitor (120) according to the switch operation state F ) and current(I F This is an example diagram showing the change.
[0051] First, referring to FIG. 3, FIG. 3 shows the current (i) flowing in the circuit. L When ) has a positive value, the voltage (V) of the flying capacitor (120) according to the on / off of the first switch (S1 (101)) and the on / off of the second switch (S2 (102)) F ) and current(I F It represents a change.
[0052] As shown in Figure 3 above, the current (i) flowing in the circuit L When the first switch (S1 (101)) is turned on when ) has a positive value, the voltage (V) of the flying capacitor (120) F ) and current (I F ) can continuously increase. And when the first switch (S1 (101)) is turned off, the voltage (V) of the flying capacitor (120) F ) remains the same and the current (I F ) can be 0.
[0053] On the other hand, when the second switch (S2(102)) is turned on, the voltage (V) of the flying capacitor (120) F ) and current (I F ) can continuously decrease. And when the second switch (S2 (102)) is turned off, the voltage (V) of the flying capacitor (120) F ) remains the same and the current (I F ) can be 0.
[0054] That is, the current flowing through the circuit (i L When ) has a positive value, the voltage (V) of the flying capacitor (120) is increased by increasing the time the first switch (S1 (101)) is turned on. F ) can be increased, and by increasing the time the second switch (S2(102)) is turned on, the voltage (V) of the flying capacitor (120) F It can reduce ).
[0055] Meanwhile, FIG. 4 shows the current (i) flowing in the circuit. LWhen ) has a negative value, the voltage (V) of the flying capacitor (120) according to the on / off of the first switch (S1 (101)) and the on / off of the second switch (S2 (102)) F ) and current(I F It represents a change.
[0056] As shown in FIG. 4, the current (i) flowing in the circuit L When the first switch (S1 (101)) is turned on when ) has a negative value, the voltage (V) of the flying capacitor (120) F ) can continuously decrease. And when the first switch (S1 (101)) is turned off, the voltage (V) of the flying capacitor (120) F ) can be maintained.
[0057] On the other hand, when the second switch (S2(102)) is turned on, the voltage (V) of the flying capacitor (120) F ) can continuously increase. And when the second switch (S2 (102)) is turned off, the voltage (V) of the flying capacitor (120) F ) can be maintained.
[0058] That is, the current flowing through the circuit (i L When ) has a negative value, the voltage (V) of the flying capacitor (120) is increased by increasing the time the first switch (S1 (101)) is turned on. F ) can be reduced, and by increasing the time the second switch (S2(102)) is turned on, the voltage (V) of the flying capacitor (120) F It can increase ).
[0059] Therefore, as shown in FIGS. 3 and 4, the current (i) flowing in the circuit L ) is a positive value (i L >0) or negative value(i L In the case where <0), the voltage (V) of the flying capacitor (120) is adjusted by controlling the on / off time, i.e., the duty ratio, of the first switch (S1 (101)) and the second switch (S2 (102)). F) can be adjusted.
[0060] However, if no load is connected to the multi-level DC / DC converter, that is, if it is in a no-load state, the current (i) flowing through the multi-level DC / DC converter circuit L ) can be 0.
[0061] FIGS. 5 and 6 are exemplary diagrams illustrating cases where the duty ratios of each switch in a multi-level DC / DC converter are changed differently when in a no-load state. FIGS. 5 and 6 show examples where the duty ratios of the first switch (S1 (101)) and the second switch (S2 (102)) are different, as shown in (a) of each figure.
[0062] In this case, when the switches of the multi-level DC / DC converter are turned on or off, the current (i) flowing through the circuit is shown in (b) of FIG. 5 and FIG. 6, respectively. L ) can increase in proportion to the time the switch is turned on. However, when the switch is turned off, the current decreases again by the same amount as the increased current, so the total current flowing through the circuit (i L ) maintains a value of 0.
[0063] In this case, as shown in (c) of FIG. 5 and FIG. 6 respectively, the current (I) flowing through the flying capacitor (120) F ) can be increased in proportion to the time the first switch (101) is turned on. And it can be decreased in proportion to the time the second switch (102) is turned on. However, as described above, the current (i) flowing in the circuit LWhen ) is 0, the current value increases from a constant negative value according to the time the first switch (101) is turned on until it reaches a current value with the same positive value, and decreases from a constant positive value according to the time the second switch (102) is turned on until it reaches a current value with the same negative value, so the sum of the increase (+) and decrease (-) can be maintained at 0.
[0064] Also, the voltage (V) of the flying capacitor (120) F As shown in (d) of FIGS. 5 and FIGS. 6, which respectively show a change in the voltage (V) of the flying capacitor (120) F ) also increases or decreases for half of the time the first and second switches (101, 102) are on, and decreases or increases at the same rate for the remaining half, so the voltage (V) of the flying capacitor (120) F The sum of the increase (+) and decrease (-) of ) can also be kept at 0.
[0065] Accordingly, the current (i) flowing through the multi-level DC / DC converter circuit L If ) is 0, that is, in a no-load state, then even when controlling the duty ratio of the switch, the voltage (V) of the flying capacitor (130) F There is a problem that the voltage (V) cannot be controlled. In this case, since the flying capacitor (130) naturally discharges, as time passes, the voltage (V) of the flying capacitor (130) F ) can gradually decrease until it is completely discharged.
[0066] Therefore, in order to reuse the multi-level DC / DC converter, after connecting the load, the voltage (V) of the flying capacitor (130) F There is a problem that switch control must be performed so that a certain ratio of the output voltage (V0) according to the number of switches (e.g., 1 / 2 when there are 2 switches) is formed. Accordingly, the time required for operation may be long.
[0067] FIG. 7 is a block diagram illustrating the configuration of a multi-level DC / DC converter according to an embodiment of the present invention for solving these problems. FIG. 8 is a conceptual diagram for explaining the operation process of a DC / DC converter according to an embodiment of the present invention.
[0068] First, referring to FIG. 7, a multi-level DC / DC converter according to an embodiment of the present invention may be configured to include a control unit (700), a current detection unit (710) and a voltage detection unit (720) controlled by the control unit (700), a proportional integrator (720), a carrier signal generation unit (740), and a switch signal generation unit (750). Additionally, as illustrated in FIG. 1, it may be configured to include a plurality of switches, a plurality of complementary switches that operate complementarily to the plurality of switches, and a flying capacitor connected between the plurality of switches and the complementary switches. Since the components illustrated in FIG. 7 are not essential for implementing the multi-level DC / DC converter, the multi-level DC / DC converter described herein may have more or fewer components than those listed above.
[0069] First, the current detection unit (710) detects the current (i) flowing through the multi-level DC / DC converter. L It can detect whether ) exists. Current (i) flowing through the multi-level DC / DC converter above. L ) has a positive or negative value when a load is connected, and can have a value of 0 when a load is not connected. That is, the current detection unit (710) detects the current (i) flowing through the multi-level DC / DC converter. LThis is for detecting whether ) is 0 (or whether the current is within a range that can be considered 0) or not, and the control unit (700) can determine whether the current load is currently connected or not based on the detection result of the current detection unit (710).
[0070] And the voltage detection unit (720) detects the output voltage (V0) of the multi-level DC / DC converter and the voltage (V) of the flying capacitor (120). F ) can be detected. In this case, the control unit (700) can detect the output voltage (V0) of the multi-level DC / DC converter and the detected voltage (V) of the flying capacitor (120). F Based on ), the flying capacitor (120) voltage (V) that must be increased or decreased F ) can be determined.
[0071] And the proportional integrator (720) has a preset reference voltage (V REF The difference between ) and the output voltage (V0) of the multi-level DC / DC converter measured above can be proportionally-integrated. In addition, a preset reference current (I REF ) and the current flowing through the above-measured multi-level DC / DC converter (i L The difference of ) can be proportionally integrated. The proportional integrator (720) is intended to reduce errors by increasing the controller output as the difference between the target value and the measured value increases, and the modulation voltage (V) that determines the on / off duty ratio of the switches from the triangular wave-shaped carrier signal according to the value of integrating the errors. M ) can be generated as an output. In this case, the above modulation voltage (V M The smaller ) is, the longer the switch-on time becomes, and the modulation voltage (V M The larger ) is, the shorter the on time of the switch can be.
[0072] In this way, since the error between the target value and the measured value can be reduced through the proportional integrator (720), when control is performed based on the output value of the proportional integrator (720), a control signal closer to the target value can be output. Accordingly, the control signal can be more stabilized. Furthermore, as the control signal closer to the target value is output, the control time can be shortened, and thus the time required until the system's response signal corresponding to the target value is output can be further shortened.
[0073] Meanwhile, the carrier signal generation unit (740) can generate a carrier signal in the form of a triangular wave. The carrier signal oscillates periodically between a negative voltage and a positive voltage having a constant value and can have a constant frequency.
[0074] And the switch signal generating unit (750) is the modulation voltage (V M A duty ratio, which is the on and off time of some of the switches among the plurality of switches, can be determined based on the carrier signal generated by the carrier signal generation unit (740) and the carrier signal generated by the carrier signal generation unit (750). For example, the switch signal generation unit (750), under the control of the control unit (700), [determines] the carrier signal as the modulation voltage (V M The switch remains in the ON state for the time during which it has a voltage greater than ), and the carrier signal is in the modulation voltage (V M The switch may be determined to be in an off state during the time when it has a voltage less than ). In this case, a switch signal may be generated in the form of a pulse wave in which the time when the switch is turned on and the time when the switch is turned off are expressed by different voltages. For example, the switch signal may be formed in the form of a pulse wave having a voltage of a preset magnitude for the time when the switch is turned on and a voltage of 0 for the time when the switch is turned off.
[0075] In addition, the switch signal generation unit (750) has the modulation voltage (V MBased on the carrier signal with the phase inverted, the duty ratio, which is the on and off time of some of the other switches among the plurality of switches, can be determined.
[0076] For example, the switch signal generating unit (750) above is the modulation voltage (V M A first switch signal can be generated to determine the duty ratio of the first switch (S1 (101)) and the first complementary switch (S1' (111)) based on the carrier signal and the above. In this case, the modulation voltage (V M Since ) has a positive value, a first switch signal can be generated in which an ON time interval is formed only in the part of the carrier signal having a positive voltage.
[0077] In addition, the switch signal generating unit (750) can invert the phase of the carrier signal. And for the phase-inverted carrier signal, a modulation voltage (V) having a positive voltage value is used. M The modulation voltage (V) from the carrier signal with the phase inverted according to ) M A second switch signal can be generated in which a time interval having a voltage greater than ) is formed as a time interval in which the switch is turned on. In this case, due to the phase inversion, the first switch signal and the second switch signal may have a phase difference of 180 degrees between the center points of each switch-on interval. Figures 5 and 6 (a) is an example in which the first switch signal and the second switch signal are displayed together.
[0078] And the control unit (700) controls each connected component and can control the overall function of the multi-level DC / DC converter.
[0079] Here, the control unit (700) can control the current detection unit (710) to check whether the load is connected or not (no-load state). And the voltage (V) of the flying capacitor (120) in different ways in the no-load state and the load connected state. F ) can be adjusted.
[0080] For example, when a load is connected, the control unit (700) controls the time at least one switch (e.g., first switch (101) or second switch (102)) is turned on, as in a conventional multi-level DC / DC converter, thereby controlling the voltage (V) of the flying capacitor (120). F ) can be adjusted.
[0081] In this case, the control unit (700) is the current (i) flowing through the multi-level DC / DC converter L The direction of ) and the voltage (V) detected from the flying capacitor (120). F At least one switch to control the duty ratio can be determined according to the output voltage (V0). And, in the case where the target voltage is determined according to the output voltage (V0), for example, configured to include two switches as in FIG. 1, the output voltage (V0) distributed to each switch, i.e., V0 / 2, and the actual voltage (V) from the flying capacitor (120). F Depending on the difference of ), the on time or off time of the switch determined by the above control can be determined.
[0082] For example, the control unit (700) has a current (i) flowing through a multi-level DC / DC converter due to a load. L When ) has a positive value, the modulation voltage (V) that determines the duty ratio of the first switch (S1(101)) M By lowering ), the time the first switch (S1 (101)) is turned on can be increased. In addition, the modulation voltage (V) that determines the duty ratio of the second switch (S2 (102)) can be increased. MBy increasing ), the time the second switch (S2 (102)) is turned on can be reduced. Then, depending on the time the first switch (S1 (101)) is turned on, the voltage (V) of the flying capacitor (120) F The time during which ) increases is the voltage (V) of the flying capacitor (120) depending on the time when the second switch (S2(102)) is turned on. F As the time for ) to decrease becomes longer than the time for the overall voltage (V) of the flying capacitor (120) F ) can be increased.
[0083] On the other hand, the control unit (700) has a current (i) flowing through the multi-level DC / DC converter due to the load. L When ) has a negative value, the modulation voltage (V) that determines the duty ratio of the first switch (S1(101)) M By increasing ), the time the first switch (S1 (101)) is turned on can be reduced. In addition, the modulation voltage (V) that determines the duty ratio of the second switch (S2 (102)) can be reduced. M By lowering ), the time the second switch (S2 (102)) is turned on can be increased. Then, depending on the time the first switch (S1 (101)) is turned on, the voltage (V) of the flying capacitor (120) F The time during which ) decreases is the voltage (V) of the flying capacitor (120) depending on the time when the second switch (S2(102)) is turned on. F As the time for ) to increase becomes shorter than the time, the overall voltage (V) of the flying capacitor (120) F ) can be increased.
[0084] On the other hand, in the case of a no-load state where no load is connected, controlling the on / off duty ratio of the switch as described above does not affect the voltage (V) of the flying capacitor (120). F) cannot be controlled. Accordingly, the control unit (700) of the multi-level DC / DC converter according to an embodiment of the present invention can control the intervals between the time intervals in which each switch is turned on to be different from each other, instead of controlling the duty ratio of the switch.
[0085] To this end, the control unit (700) can make the time interval during which all switches are turned off different for each cycle in which each switch is turned on, thereby making the interval between time intervals during which different switches are turned on in the same cycle narrower or wider. By doing so, the voltage (V) of the flying capacitor (120) that increases or decreases as the first switch (101) or the second switch (102) is turned off F By turning on the first switch (101) or the second switch (102) again before the voltage (V) of the flying capacitor (120) is decreased by an increase amount or increased by a decrease amount, the voltage (V) of the flying capacitor (120) F ) allows the voltage (V) of the flying capacitor (120) to be increased or decreased again. Accordingly, the voltage (V) of the flying capacitor (120) gradually increases. F It can increase ).
[0086] For example, when the first switch (S1 (101)) is turned on, the voltage (V) of the flying capacitor (120) F When ) is reduced and the second switch (S2(102)) is turned on, the voltage (V) of the flying capacitor (120) F Assuming the case where ) is increased, when the first switch (S1 (101)) is turned off, by shortening the time between the first switch (S1 (101)) being turned off and the second switch (S2 (102)) being turned on, the increased voltage (V) of the flying capacitor (120) F The second switch (S2(102)) can be turned on before ) is completely reduced, that is, before it is reduced by the increase amount. Therefore, the voltage (V) of the flying capacitor (120) F ) can be made to have a value greater than 0.
[0087] Additionally, by bringing forward the point in time when the second switch (S2 (102)) turns on after the first switch (S1 (101)) turns off, the time from when the second switch (S2 (102)) turns off and the first switch (S1 (101)) turns on, that is, the time from when the second switch (S2 (102)) turns off until the end of the cycle can be increased. In this case, the voltage (V) of the flying capacitor (120) F As the ON time of the second switch (S2(102)) that increases, the voltage (V) of the flying capacitor (120) increases F The increase amount can be further increased.
[0088] Conversely, in the same case, when the first switch (S1 (101)) is turned off, the time between the first switch (S1 (101)) being turned off and the second switch (S2 (102)) being turned on is increased, thereby increasing the voltage (V) of the flying capacitor (120). F The time during which ) is reduced can be increased. And the second switch (S2(102)) can be turned on.
[0089] In this case, the time at which the second switch (S2(102)) turns on after the first switch (S1(101)) turns off is delayed, thereby shortening the time from when the second switch (S2(102)) turns off and the first switch (S1(101)) turns on, that is, from when the second switch (S2(102)) turns off until the end of the cycle. In this case, the reduced voltage (V) of the flying capacitor (120) F The second switch (S2 (102)) can be turned on before the voltage of the flying capacitor (120) increases completely, that is, before it increases by the amount of decrease. Therefore, the voltage (V) of the flying capacitor (120) F It is possible to make ) have a value less than 0.
[0090] In this way, by making the time interval from when one switch is turned off until another switch is turned on different for each switch in each cycle, that is, by making the first time interval from when the first switch is turned off until the second switch is turned on and the second time interval from when the second switch is turned off until the first switch is turned on different from each other, the control unit (700) [controls] the voltage (V) of the flying capacitor (120). F The voltage of ) can be adjusted to increase or decrease. In addition, if the time interval from when one switch is turned off until another switch is turned on is made different for each switch as in this way, regardless of the duty cycle, the time interval for different switches to be turned on is used, so the voltage (V) of the flying capacitor (120) as shown in FIGS. 5 and 6 above F Even if the voltage of the flying capacitor (120) increases by the amount of the reduced voltage value or decreases by the amount of the increased voltage value depending on the on and off of the switch, the voltage (V) of the flying capacitor (120) F The voltage of ) can be increased or decreased. Therefore, even when no load is connected to the multi-level DC / DC converter, the voltage (V) of the flying capacitor (120) can be controlled via switch control. F The voltage of ) can be adjusted.
[0091] In order for the time interval from when one switch is turned off until another switch is turned on to vary for each switch, the control unit (700) of the multi-level DC / DC converter according to an embodiment of the present invention may delay (phase delay) the carrier signal that generates the switch signal of any one switch or the other switch. That is, if a delay value having a negative value is set for the second carrier signal that generates the switch signal of the second switch with respect to the first carrier signal that generates the switch signal of the first switch, the time interval from when the first switch is turned off until the second switch is turned on may be shortened. On the other hand, if a delay value having a positive value is set for the second carrier signal that generates the switch signal of the second switch with respect to the first carrier signal that generates the switch signal of the first switch, the time interval from when the first switch is turned off until the second switch is turned on may be increased. In this case, whether to set the negative delay value or the positive delay value depends on the voltage (V) of the flying capacitor (120). F Whether to increase or decrease the voltage of ) and, when the switch is turned on, the voltage (V) of the flying capacitor (120) F It can be determined depending on whether the voltage of ) increases or decreases. In addition, the magnitude of the delay value is the output voltage (V0) distributed to each switch, for example, V0 / 2 in the case of having two switches, and the actual voltage (V) from the flying capacitor (120). F It can be determined depending on the difference of ).
[0092] Meanwhile, the memory (760) can store various data for controlling the control unit (700). For example, the memory (760) can store information on the target voltage determined by the number of switches provided. In addition, the memory (760) can store a preset reference voltage (V REF ) and reference current (I REFInformation of ) can be stored. In addition, the output voltage (V0) detected by the voltage detection unit (720) and the voltage (V) of the flying capacitor (120) F At least one of the following information may be stored. In addition, information regarding a carrier signal may be stored in the memory (760). For example, the information regarding the carrier signal may include information regarding the frequency or delay value (D angle) of the carrier signal.
[0093] Meanwhile, FIG. 9 is a flowchart illustrating the operation process of a multi-level DC / DC converter according to an embodiment of the present invention.
[0094] Referring to FIG. 9, the control unit (700) of a multi-level DC / DC converter according to an embodiment of the present invention first detects the current (i) flowing through the DC / DC converter via the current detection unit (710). L ) can be detected (S900). In this case, if a load is connected to the DC / DC converter, the current flowing through the DC / DC converter (i L ) can have a positive or negative value. On the other hand, if no load is connected to the DC / DC converter, the current flowing through the DC / DC converter (i L ) can have a value of 0.
[0095] And the control unit (700) is the current voltage (V) of the flying capacitor (120). F ) can be detected. In addition, the control unit (700) can detect the output voltage (V0) of the DC / DC converter. And the control unit (700) can calculate a target voltage based on the output voltage (V0) (S902). And the control unit (700) can calculate the target voltage calculated in step S902 and the current voltage (V) of the flying capacitor (120). F Based on ), the voltage (V) of the flying capacitor (120) above FThe voltage control direction of ) can be determined, for example, voltage rise or voltage drop (S904). In this case, the control unit (700) determines the current voltage (V of the flying capacitor (120) at the target voltage. F If ) is insufficient, the voltage rises, and the current voltage (V) of the flying capacitor (120) is lower than the above target voltage. F If ) is exceeded, it can be determined that a voltage drop is necessary.
[0096] In step S904, when the voltage control direction for the flying capacitor (120) is determined, the control unit (700) can check whether the current state is a no-load state based on the current detection result detected in step S900 (S906). And if the result of the check in step S906 is that there is no load currently connected to the DC / DC converter, at least one carrier signal to delay the phase can be determined according to the voltage control direction determined in step S904 (S908).
[0097] In the above S908 step, the control unit (700) may determine a carrier signal that generates a switch signal for either a switch that increases the voltage of the flying capacitor (120) when turned on or a switch that decreases the voltage of the flying capacitor (120) when turned on, as a carrier signal to delay the phase according to the voltage control direction. And the voltage (V) of the flying capacitor (120) detected in the above S902 step F Depending on the difference between the target voltage and the carrier signal determined in step S908, the phase delay value (phase delay angle or phase delay time) of the carrier signal can be determined (S910).
[0098] In this case, the larger the phase delay value, the shorter or longer the time interval between the point when one switch is turned off and the point when another switch is turned on may become. Therefore, the larger the phase delay value, the voltage (V) of the flying capacitor (120) FThe increase in ) can be greater. Therefore, the voltage (V) of the flying capacitor (120) F The greater the difference between ) and the above target voltage, the larger the phase delay value can be determined.
[0099] When a phase delay value is determined in step S910, the control unit (700) can delay the carrier signal for one switch determined in step S908 with respect to the carrier signal for another switch according to the determined phase delay value (S912).
[0100] Accordingly, the first time interval from when the first switch is turned off until the second switch is turned on, and the second time interval from when the second switch is turned off until the first switch is turned on, may differ from each other. In this case, if the first time interval decreases, the second time interval increases, and if the first time interval increases, the second time interval may decrease. And as the first time interval and the second time interval differ from each other, the flying capacitor (120) increases again before the voltage is completely decreased or decreases again before the voltage is completely increased, so the voltage (V) of the flying capacitor (120) F ) can be increased or decreased. That is, through the phase delay of either carrier signal, the voltage (V) of the flying capacitor (120) in the no-load state F ) can be adjusted.
[0101] Meanwhile, if, as a result of the check in step S906 above, there is a load connected to the DC / DC converter, the control unit (700) can first initialize the phase delay value of each carrier signal (S914). Accordingly, the first time interval from when the first switch is turned off until the second switch is turned on, and the second time interval from when the second switch is turned off until the first switch is turned on, can be changed to be the same.
[0102] When the phase delay value of each carrier signal is initialized in step S914 above, the control unit (700) determines the current (i) of the DC / DC converter determined in step S900 above. L Depending on the direction (positive or negative) and the voltage control direction determined in step S904, the switch to control the switch driving time can be determined (S916). For example, as described above, the current (i L ) has a positive value, and when the first switch is turned on, the voltage (V) of the flying capacitor (120) F ) increases, and when the second switch is turned on, the voltage (V) of the flying capacitor (120) F When ) is reduced, the control unit (700) can determine the first switch or the second switch as the switch to control the switch driving time according to the voltage control direction calculated in step S904.
[0103] Meanwhile, in the above S916 step, when the switch to control the switch driving time is determined, the control unit (700) [controls] the voltage (V) of the flying capacitor (120) detected in the above S902 step. F A control time to control switch driving can be determined based on the difference between ) and the target voltage (S918).
[0104] And when the above control time is determined, the control unit (700) can control the driving time of the switch determined in step S916 according to the control time determined in step S918 (S920). In this case, the voltage (V) of the flying capacitor (120) F The greater the difference between ) and the target voltage, the longer the control time may be. And through the control of the switch driving time, the voltage (V) of the flying capacitor (120) F ) may increase or decrease.
[0105] The voltage (V) of the flying capacitor (120) through the above S912 or S920 step FWhen ) is adjusted, the control unit (700) proceeds again to step S900 to detect whether there is a connected load through the current flowing through the DC / DC converter. Then, through steps S902 to S904, the voltage (V) of the flying capacitor (120) F ) and the voltage (V) of the flying capacitor (120) F The voltage control direction of ) can be determined. Then, proceeding again to step S906, the voltage (V) of the flying capacitor (120) in accordance with the detection result of step S900 F ) can be adjusted.
[0106] Therefore, if the load is connected, the voltage (V) of the flying capacitor (120) through steps S916 to S920 above F In a state where the load is being controlled, if the load is removed, the control unit (700) delays the phase of the carrier signal according to the check result of step S906, thereby controlling the voltage (V) of the flying capacitor (120). F ) can be adjusted. Also, if the load is not connected and it is in a no-load state, the voltage (V) of the flying capacitor (120) through steps S908 to S912 above can be adjusted. F If the load is reconnected while the voltage (V) of the flying capacitor (120) is being controlled, the control unit (700) controls at least one switch driving time according to the check result of step S906. F ) can be adjusted. That is, the multi-level DC / DC converter according to an embodiment of the present invention can adjust the voltage (V) of the flying capacitor (120) in different ways depending on whether a load is connected. F ) can be adjusted.
[0107] Meanwhile, FIG. 10 shows the voltage (V) of a flying capacitor according to the phase delay of a carrier signal in a no-load state in a DC / DC converter according to an embodiment of the present invention described above. FThis is an example illustrating an example where the amount of increase and decrease differs.
[0108] Referring to FIG. 10, the control unit (700) of the DC / DC converter according to an embodiment of the present invention can phase delay a first carrier signal that generates a switch signal of the first switch, or a second carrier signal that generates a switch signal of the second switch, so that within a time interval in which each switch is turned on, i.e., one cycle, the first time interval (1000) between the time when one switch (first switch) is turned off and the time when another switch (second switch) is turned on, and the second time interval (1010) between the time when the other switch (second switch) is turned off and the time when one switch (first switch) is turned on are different from each other.
[0109] For example, the control unit (700) can delay the phase of the first carrier signal by a certain value (D angle) while the second carrier signal is fixed. In this case, as shown in (c) and (d) of FIG. 10, the first time interval (1000) between the time when the first switch is turned off and the time when the second switch is turned on can be shortened, and the second time interval (1010) between the time when the second switch is turned off and the time when the cycle ends and the first switch is turned on again can be increased. That is, the first time interval (1000) and the second time interval (1010) can be changed complementarily to each other.
[0110] In this case, when the first switch is turned on, the voltage (V) of the flying capacitor (120) F When ) is reduced and the second switch is turned on, the voltage (V) of the flying capacitor (120) FIf ) is increased, as shown in (d) of FIG. 10 above, the voltage (V) of the flying capacitor (120) according to the short time interval between the off time of the first switch and the on time of the second switch F ) can be increased again before it is completely decreased.
[0111] Therefore, the voltage increase (+) becomes greater than the voltage decrease (-), so the voltage (V) of the flying capacitor (120) F ) can be increased.
[0112] Also, the voltage (V) of the flying capacitor (120) F Since the second switch is turned on when ) is increased, the voltage (V) of the flying capacitor (120) during the ON time of the second switch F ) can be further increased.
[0113] Therefore, as shown in FIG. 10 (d), during one cycle, the amount of voltage change having a positive value can be greater than the amount of voltage change having a negative value. Therefore, overall, the voltage (V) of the flying capacitor (120) F ) can be increased.
[0114] Meanwhile, although steps S916 to S920 of FIG. 9 described above explain selecting one switch and controlling the selected switch, steps S916 to S920 may, conversely, be steps of determining the control time for a plurality of switches and controlling each of the plurality of switches. In this case, the driving time of one of the plurality of switches may be controlled to be longer, and the other may be controlled to be shorter.
[0115] Likewise, while steps S908 through S912 described delaying the phase of a single carrier signal, it is also possible to delay the phases of multiple carrier signals. In this case, the phases of the multiple carrier signals may be delayed in opposite directions.
[0116] In other words, if one carrier signal is phase-delayed according to a positive phase delay value, the other carrier signal may be phase-delayed according to a negative phase delay value.
[0117] In this case, the first time interval between the point when the first switch is turned off and the point when the second switch is turned on, and the second time interval between the point when the second switch is turned off and the point when the first switch is turned on, can be shortened or extended more significantly than delaying the phase of a single carrier signal.
[0118] Meanwhile, although specific embodiments have been described in the above description of the present invention, various modifications may be made without departing from the scope of the present invention.
[0119] In particular, in the embodiment of the present invention, a case in which a plurality of switches are composed of two switches, a first switch and a second switch, and a flying capacitor is provided accordingly has been described as an example, but this is merely one embodiment of the present invention and the present invention is not limited thereto.
[0120] That is, any number of switches can be distributed, and accordingly, more flying capacitors may be provided. In this case, the control unit (700) of the multi-level converter according to the embodiment of the present invention may determine, for each switch that operates complementarily to one another, the phase delay time of the carrier signal that determines the on / off time, i.e., the duty ratio, of each switch. In this case, the carrier signals that determine the duty ratio of each switch may be delayed differently from each other.
[0121] The present invention described above can be implemented as computer-readable code on a medium on which a program is recorded. A computer-readable medium includes all types of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable media include HDD (Hard Disk Drive), SSD (Solid State Disk), SSD (Silicon Disk Drive), ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc., and also include implementation in the form of a carrier wave (e.g., transmission over the Internet).
[0122] Additionally, the computer may include a control unit (700) of a multi-level DC / DC converter. Accordingly, the above detailed description should not be interpreted restrictively in all respects and should be considered exemplary. The scope of the invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the invention are included within the scope of the invention.
Claims
1. A DC / DC converter comprising a plurality of switches in which the output voltage is evenly distributed and at least one flying capacitor disposed between the plurality of switches, A current detection unit for detecting the current flowing in the internal circuit of the above DC / DC converter; A voltage detection unit for detecting the voltage of the flying capacitor and the output voltage of the DC / DC converter; and, A DC / DC converter characterized by including a control unit that controls the voltage of the flying capacitor according to the detection result of the current detection unit, in any one of the following methods: a first method for controlling the driving time of at least one of a first switch in which the voltage of the flying capacitor rises when the plurality of switches are turned on and a second switch in which the voltage of the flying capacitor falls when the switch is turned off; or a second method for delaying the phase of at least one of a first carrier signal for generating a switch signal for determining the switch duty ratio of the first switch or a second carrier signal for generating a switch signal for determining the switch duty ratio of the second switch.
2. In paragraph 1, the control unit is, A DC / DC converter characterized by checking whether a load is connected to the DC / DC converter based on whether the current flowing in the internal circuit of the DC / DC converter is 0 or within a range where it can be considered 0, based on the detection result of the current detection unit, and controlling the voltage of the flying capacitor in either the first method or the second method based on the load check result.
3. In paragraph 2, the control unit is, A DC / DC converter characterized by initializing the phase delay time of the first carrier signal and the second carrier signal when controlling the voltage of the flying capacitor according to the first method above.
4. In paragraph 1, the control unit is, A DC / DC converter characterized by determining a target voltage of the flying capacitor according to the output voltage and the number of switches provided in the plurality of switches, and determining the driving time of the at least one switch or the phase delay time of the at least one carrier signal according to the difference between the determined target voltage and the voltage of the detected flying capacitor.
5. In Paragraph 1, The above carrier signal is, It is a signal in the form of a triangular wave that oscillates periodically between a negative voltage and a positive voltage with a constant value and has a constant frequency, The above switch signal is, A DC / DC converter characterized by a signal formed according to the above carrier signal and a preset modulation voltage, wherein the ratio of the time a specific switch is turned on and off is determined differently depending on the magnitude of the modulation voltage.
6. In paragraph 1, the control unit is, A DC / DC converter characterized by delaying the phase of at least one of a carrier signal corresponding to one switch and a carrier signal corresponding to another switch, such that a first time interval between the time when one switch is turned off and the time when another switch is turned on, and a second time interval between the time when the other switch is turned off and the time when one switch is turned on are different from each other.
7. In paragraph 6, the control unit is, A DC / DC converter characterized in that the first time interval and the second time interval are changed in opposite ways.
8. In Paragraph 1, The above plurality of switches are, It includes a plurality of complementary switches that switch complementarily to each of the plurality of switches mentioned above, The above flying capacitor is, A DC / DC converter characterized by being positioned between the plurality of switches and between the plurality of complementary switches.
9. A control method for a DC / DC converter comprising a plurality of switches in which the output voltage is evenly distributed and at least one flying capacitor disposed between the plurality of switches, wherein A step of detecting the current flowing in the internal circuit of the above DC / DC converter; A step of detecting the voltage of the flying capacitor and the output voltage of the DC / DC converter; When the current detection result determines that a load is connected to the DC / DC converter, a step of controlling the voltage of the flying capacitor according to a first method of controlling the driving time of at least one of a first switch, which causes the voltage of the flying capacitor to rise when turned on among the plurality of switches, and a second switch, which causes the voltage of the flying capacitor to fall when turned off; and, A method for controlling a DC / DC converter, characterized by including the step of controlling the voltage of the flying capacitor in a second method of delaying the phase of at least one of a first carrier signal for generating a switch signal for determining the switch duty ratio of the first switch or a second carrier signal for generating a switch signal for determining the switch duty ratio of the second switch, when the detection result of the current detection unit determines that the load is not connected to the DC / DC converter.
10. In Paragraph 9, The step of detecting the current flowing in the internal circuit of the above DC / DC converter is, If the current flowing through the internal circuit of the above DC / DC converter is 0 or within a range where it can be considered as 0, it is determined that a load is connected to the above DC / DC converter, and A control method for a DC / DC converter characterized by a step of determining that a load is not connected to the DC / DC converter when the current flowing through the internal circuit of the DC / DC converter has a positive or negative value exceeding the range that can be considered as zero.
11. In Paragraph 10, The step of detecting the voltage of the flying capacitor and the output voltage of the DC / DC converter is, A step of determining the target voltage of the flying capacitor according to the output voltage and the number of switches provided in the plurality of switches; and, A method for controlling a DC / DC converter, characterized by further including the step of calculating the voltage difference between the target voltage and the detected flying capacitor, and determining the direction to control the voltage of the flying capacitor according to the calculated voltage difference.
12. In Paragraph 11, The step of controlling the voltage of the flying capacitor according to the first method above is, A step of determining a switch corresponding to the first switch and a switch corresponding to the second switch based on whether the current flowing through the internal circuit of the DC / DC converter has a positive value or a negative value; A step of determining the switch to control the driving time among the first switch and the second switch according to the voltage control direction determined above; A step of determining the length of the driving time to be controlled according to the difference between the target voltage and the voltage of the detected flying capacitor; and, A method for controlling a DC / DC converter, characterized by including the step of controlling at least one on and off switch determined as the switch to be controlled among the switch corresponding to the first switch and the switch corresponding to the second switch, according to the control length of the determined driving time.
13. In Paragraph 12, The step of controlling the voltage of the flying capacitor according to the first method above is, A method for controlling a DC / DC converter characterized by including a step of initializing the phase delay time of the first carrier signal and the second carrier signal when controlling the voltage of the flying capacitor according to the first method above.
14. In Paragraph 11, The step of controlling the voltage of the flying capacitor according to the first method above is, A step of determining a switch corresponding to the first switch and a switch corresponding to the second switch in a no-load state; A step of determining at least one of the first carrier signal and the second carrier signal to delay the phase according to the difference between the target voltage and the voltage of the detected flying capacitor according to the voltage control direction determined above; A step of determining the phase delay value to be delayed according to the difference between the target voltage and the voltage of the detected flying capacitor; and, A control method for a DC / DC converter characterized by including the step of delaying at least one of the first carrier signal and the second carrier signal determined according to the determined phase delay value and generating at least one switch signal according to the at least one carrier signal with the phase delayed.
15. In Paragraph 14, The step of generating a switch signal according to the phase-delayed carrier signal is: A control method for a DC / DC converter characterized by the step of generating a switch signal for determining the duty ratio of one switch and a switch signal for determining the duty ratio of another switch, wherein, due to the above-mentioned phase delay, a first time interval between the time when one switch is turned off and the time when another switch is turned on, and a second time interval between the time when the other switch is turned off and the time when one switch is turned on are different from each other.