Resonant switched capacitor converter, its controller circuit, and electronic device using the same

Abstract

To provide a resonance switched capacitor converter with improved efficiency.SOLUTION: In a first state φ1, a first switch SW1 and a third switch SW3 are ON, and a second switch SW2 and a fourth switch SW4 are OFF. In a second state φ2, the second switch SW2 and the fourth switch SW4 are ON, and the first switch SW1 and the third switch SW3 are OFF. In a third state φ3, the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 are OFF. A controller IC 200 sequentially repeats the first state φ1 to the third state φ3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to resonant switched capacitor converters. [Background technology]

[0002] DC / DC converters and charge pumps are used to generate voltages higher or lower than the power supply voltage. DC / DC converters that use inductors as energy storage elements can control the output voltage, but they have the problem of reduced efficiency due to switching operations.

[0003] In applications that require high efficiency, switched capacitor converters (charge pumps) are used, which do not require inductors as energy storage elements. One type of switched capacitor converter known is one that adds a resonant inductor in series with the flying capacitor to achieve resonant operation (called a resonant switched capacitor converter). A resonant switched capacitor converter enables zero-current switching (soft switching), enabling highly efficient operation.

[0004] One type of resonant switched capacitor converter is known as a switched tank converter, which is a configuration in which an inductor is added to a Dickson-type charge pump. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 9917517 Summary of the Invention [Problem to be solved by the invention]

[0006] It is in this context that the present disclosure has been made, and one of its exemplary objects is to provide a resonant switched-capacitor converter with improved efficiency. [Means for solving the problem]

[0007] One aspect of the present disclosure relates to a controller circuit for a resonant switched capacitor converter. The resonant switched capacitor converter includes a first switch and a second switch connected in series between an input line and an output line, a third switch and a fourth switch connected in series between the output line and a ground line, and a capacitor and an inductor connected in series across the second and third switches. In a first mode, the controller circuit cycles sequentially between a first state in which the first switch and the third switch are on and the second switch and the fourth switch are off, a second state in which the second switch and the fourth switch are on and the first switch and the third switch are off, and a third state in which the first switch, the second switch, the third switch, and the fourth switch are off.

[0008] Any combination of the above elements, or mutual substitution of elements or expressions between methods, devices, systems, etc., are also valid aspects of the present invention or the present disclosure. Furthermore, the description in this section (Means for Solving the Problems) does not explain all essential features of the present invention, and therefore, subcombinations of the described features may also constitute the present invention. [Effects of the Invention]

[0009] According to certain aspects of the present disclosure, the efficiency of a resonant switched capacitor converter can be improved. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a circuit diagram of a resonant switched capacitor converter according to an embodiment. [Figure 2]FIG. 2 is an equivalent circuit diagram of the second mode of the resonant switched capacitor converter in state I. [Figure 3] FIG. 3 is an equivalent circuit diagram of the second mode of the resonant switched capacitor converter in state II. [Figure 4] FIG. 4 is an equivalent circuit diagram of the second mode of the resonant switched capacitor converter in state III. [Figure 5] FIG. 5 is an equivalent circuit diagram of the second mode of the resonant switched capacitor converter in state IV. [Figure 6] FIG. 6 is a time chart illustrating the operation of the resonant switched capacitor converter in the second mode. [Figure 7] FIG. 7 is a diagram showing the relationship between the phase difference φd and the output current IOUT. [Figure 8] FIG. 8 is a waveform diagram of the coil current IL in the resonant switching converter operating in the second mode under heavy and light load conditions. [Figure 9] FIG. 9 is an equivalent circuit diagram of the resonant switched capacitor converter in the state φ1 of the first mode. [Figure 10] FIG. 10 is an equivalent circuit diagram of the resonant switched capacitor converter in the state φ2 of the first mode. [Figure 11] FIG. 11 is an equivalent circuit diagram of the resonant switched capacitor converter in the state φ3 of the first mode. [Figure 12] FIG. 12 is a time chart illustrating the operation of the resonant switched capacitor converter in the first mode. [Figure 13] FIG. 13 is a circuit diagram showing an example of the configuration of the controller IC. [Figure 14] FIG. 14 is an operational waveform diagram of the controller of FIG. [Figure 15] FIG. 15 is a diagram illustrating an example of an electronic device including a resonant switched capacitor converter. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Outline of the embodiment) A summary of some exemplary embodiments of the present disclosure is provided. This summary is intended to provide a simplified overview of some concepts of one or more embodiments in order to provide a basic understanding of the embodiments as a prelude to the more detailed description that follows. It is not intended to limit the scope of the invention or disclosure. This summary is not an exhaustive overview of all possible embodiments, and is not intended to identify key elements of all embodiments or to delineate the scope of some or all aspects. For convenience, the term "one embodiment" may refer to one embodiment (example or variant) or multiple embodiments (examples or variants) disclosed herein.

[0012] According to one embodiment, a controller circuit controls a resonant switched capacitor converter including a first switch and a second switch connected in series between an input line and an output line, a third switch and a fourth switch connected in series between the output line and a ground line, and a capacitor and an inductor connected in series across the second and third switches. In a first mode, the controller circuit cycles through a first state in which the first and third switches are on and the second and fourth switches are off, a second state in which the second and fourth switches are on and the first and third switches are off, and a third state in which the first, second, third, and fourth switches are off.

[0013] According to this configuration, by operating in the first mode under light load, zero voltage switching can be maintained and efficiency can be improved.

[0014] In one embodiment, in the second mode, the controller circuit cycles through a state in which the first switch and the fourth switch are on and the second switch and the third switch are off, a state in which the first switch and the third switch are on and the second switch and the fourth switch are off, a state in which the second switch and the third switch are on and the first switch and the fourth switch are off, and a state in which the second switch and the fourth switch are on and the first switch and the third switch are off.

[0015] In one embodiment, the controller circuit may switch between the first and second modes depending on the load conditions.

[0016] In one embodiment, the controller circuit may transition to the first mode when the output current of the resonant switched capacitor converter becomes zero.

[0017] In one embodiment, while operating in the first mode, the controller circuit may transition to the first state when the output voltage of the resonant switched capacitor converter drops to a threshold voltage in the third state.

[0018] In one embodiment, while operating in the first mode, the length of the first state may be fixed.

[0019] In one embodiment, while operating in the first mode, a transition to the third state may occur when the current in the inductor reaches zero in the second state.

[0020] In one embodiment, the controller circuit may be monolithically integrated on a single semiconductor substrate. "Monolithic integration" includes cases where all of the circuit components are formed on a semiconductor substrate, or where the main circuit components are monolithically integrated, and some resistors, capacitors, etc., for adjusting circuit constants may be provided outside the semiconductor substrate. By integrating the circuit on a single chip, the circuit area can be reduced and the characteristics of the circuit elements can be maintained uniformly.

[0021] (Embodiment) The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. Furthermore, the embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0022] In this specification, "a state in which component A is connected to component B" includes not only a case in which component A and component B are directly physically connected to each other, but also a case in which component A and component B are indirectly connected to each other via other components that do not substantially affect the electrical connection between them or that do not impair the function or effect achieved by their connection.

[0023] Similarly, "a state in which component C is provided between component A and component B" includes not only cases in which components A and C, or components B and C, are directly connected, but also cases in which they are indirectly connected via other components that do not substantially affect the electrical connection state between them or impair the functions or effects achieved by their combination.

[0024] Furthermore, "signal A (voltage, current) corresponds to signal B (voltage, current)" means that signal A has a correlation with signal B, and specifically means (i) when signal A is signal B, (ii) when signal A is proportional to signal B, (iii) when signal A is obtained by level-shifting signal B, (iv) when signal A is obtained by amplifying signal B, (v) when signal A is obtained by inverting signal B, (vi) or any combination thereof. Those skilled in the art will understand that the scope of "corresponding to" is determined depending on the type and application of signals A and B.

[0025] The vertical and horizontal axes of the waveform diagrams and time charts referred to in this specification have been appropriately enlarged or reduced to facilitate understanding, and the waveforms shown have been simplified, exaggerated, or emphasized to facilitate understanding.

[0026] (Embodiment) 1 is a circuit diagram of a resonant switched capacitor converter 100 according to an embodiment. The resonant switched capacitor converter 100 has a gain of 1 / 2 and receives an input voltage V IN is stepped down by half and the output voltage V OUT =V IN The resonant switched capacitor converter 100 includes two capacitors C1 and C2, one inductor L1, four switches SW1 to SW4, and a controller IC (Integrated Circuit) 200.

[0027] This resonant switched capacitor converter 100 has a configuration in which an inductor is added in series with the flying capacitor of a 1 / 2 charge pump.

[0028] The first switch SW1 and the second switch SW2 are connected in series between the input line 102 and the output line 104. The third switch SW3 and the fourth switch SW4 are connected in series between the output line 104 and the ground line 108. A flying capacitor C1 and an inductor L1 are connected in series between both ends of the second switch SW2 and the third switch SW3 to form an LC resonant circuit (tank circuit) 106. An output capacitor C2 is connected to the output line 104. The connection node between the first switch SW1 and the second switch SW2 is denoted as n1, and the connection node between the third switch SW3 and the fourth switch SW4 is denoted as n3.

[0029] In the first mode, the controller IC 200 cycles through the first state φ1 to the third state φ3 in sequence. First state φ1 First switch SW1 and third switch SW3: ON Second switch SW2 and fourth switch SW4: OFF

[0030] Second state φ2 Second switch SW2 and fourth switch SW4: ON First switch SW1 and third switch SW3: OFF

[0031] Third state φ3 First switch SW1, second switch SW2, third switch SW3, fourth switch SW4: OFF

[0032] In addition to the first mode, the controller IC 200 can also operate in a second mode. In the second mode, the controller IC 200 sequentially repeats the following states I to IV. Condition I First switch SW1 and fourth switch SW4: ON Second switch SW2 and third switch SW3: OFF Condition II First switch SW1 and third switch SW3: ON Second switch SW2 and fourth switch SW4: OFF Condition III Second switch SW2 and third switch SW3: ON First switch SW1 and fourth switch SW4: OFF Condition IV Second switch SW2 and fourth switch SW4: ON First switch SW1 and third switch SW3: OFF

[0033] The controller IC 200 is a functional IC integrated on a single semiconductor substrate, and includes a drive circuit 210, a state control unit 220, and a light load detection circuit 230. Gate pins G1 to G4 of the controller IC 200 are connected to the gates of the first switch SW1 to the fourth switch SW4.

[0034] State control unit 220 is a control logic that generates control signals S1 to S4 that define the on / off states of first switch SW1 to fourth switch SW4, and controls the state of resonant switched capacitor converter 100. In the first mode, first state φ1 to third state φ3 are repeated in sequence. In the second mode, state control unit 220 repeats state I to state IV in sequence.

[0035] The drive circuit 210 drives the first switch SW1 to the fourth switch SW4 in accordance with the outputs S1 to S4 of the state control unit 220. The drive circuit 210 includes four drivers Dr1 to Dr4.

[0036] The controller IC 200 switches between the first mode and the second mode depending on the load state. The light load detection circuit 230 monitors the load state, and selects the first mode when it determines that the load state is light, and selects the second mode when it determines that the load state is not light (heavy).

[0037] The light load detection circuit 230 detects the output current I OUT may be directly monitored, or the coil current I flowing through the LC resonant circuit 106 may be monitored. L For example, the light load detection circuit 230 may monitor the output current I of the resonant switched capacitor converter 100. OUT When becomes zero, it is determined that the load is light and the system transitions to the first mode.

[0038] The above is the configuration of the resonant switched capacitor converter 100. Next, the operation will be described.

[0039] First, the operation in the second mode will be described. As described above, in the second mode, states I to IV are repeated.

[0040] 2 is an equivalent circuit diagram of the resonant switched capacitor converter 100 in the second mode, state I. The voltages of the switching nodes n1 and n3 are denoted as Vn1 and Vn3. In state I, Vn1=V IN Vn3=0V When the voltage across the flying capacitor C1 is Vc, the voltage across the inductor L1 is ΔV L(I) teeth, ΔV L(I) =V IN It becomes -Vc. Therefore, in state I, the coil current I flows through inductor L1.L The slope of (V IN -Vc) / L This becomes:

[0041] 3 is an equivalent circuit diagram of the second mode of resonant switched capacitor converter 100 in State II. In State II, Vn1=V IN Vn3=V OUT When the voltage across the flying capacitor C1 is Vc, the voltage across the inductor L1 is ΔV L(II) teeth, ΔV L(II) =V IN -Vc-V OUT This becomes: Therefore, in state II, the coil current I flowing through inductor L1 L The slope of (V IN -Vc-V OUT ) / L This becomes:

[0042] 4 is an equivalent circuit diagram of the second mode of resonant switched capacitor converter 100 in State III. In State III, Vn1=Vn3 When the voltage across the flying capacitor C1 is Vc, the voltage across the inductor L1 is ΔV L(III) teeth, ΔV L(III) =-Vc. Therefore, in state III, the coil current I flowing through inductor L1 L The slope of (-Vc) / L This becomes:

[0043] 5 is an equivalent circuit diagram of the second mode of resonant switched capacitor converter 100 in State IV. In State IV, Vn1=V OUT Vn3=0V When the voltage across the flying capacitor C1 is Vc, the voltage across the inductor L1 is ΔV L(IV) teeth, ΔV L(IV) =V OUT It becomes -Vc. Therefore, in state IV, the coil current I flowing through inductor L1 L The slope of (V OUT -Vc) / L This becomes:

[0044] 6 is a time chart illustrating the operation of the resonant switched capacitor converter 100 in the second mode. The pair of the first switch SW1 and the second switch SW2 is called the reference phase, and the state in which the first switch SW1 is on and the second switch SW2 is off is defined as the H state, and the state in which the first switch SW1 is off and the second switch SW2 is on is defined as the L state. The pair of the third switch SW3 and the fourth switch SW4 is called the control phase, and the state in which the third switch SW3 is on and the fourth switch SW4 is off is defined as the H state, and the state in which the third switch SW3 is off and the fourth switch SW4 is on is defined as the L state. In FIG. 6, the coil current I L The states of the reference phases SW1 and SW2 and the control phases SW3 and SW4 are shown.

[0045] The hatched coil current I in states II and IV L is supplied to the load as output current.

[0046] Also I L The area of ​​the region where I is the charging current to the flying capacitor C1 is I L The area where I<0 is the discharge current to the flying capacitor C1. In steady state, I L >0 region and I L The areas of the <0 regions are equal.

[0047] If we impose the constraints that the length of state I is equal to the length of state III, and the length of state II is equal to the length of state IV, then the coil current I in states I and III is L The absolute values ​​of the slopes of are equal, and the coil current I in states II and IVL The absolute values ​​of the slopes of the lines must be equal. In this case, the following equation is obtained: (V IN -Vc) / L=|(-Vc)| / L (V IN -Vc-V OUT ) / L=|(V OUT -Vc)| / L Solving this, in steady state, Vc=V IN / 2 holds true.

[0048] This completes the second mode operation of the resonant switched capacitor converter 100. In the states shown in Figure 6, all transitions are zero voltage switching. The coil current I in State I L The change in ΔI L(I) and the coil current I in state III L The change in ΔI L(III) This causes ripple loss, but by reducing the inductance of inductor L1 and shortening the time, ripple loss can be suppressed. Also, when the voltage Vc of flying capacitor C1 is V IN / 2, so the coil current in state II is I L The change in ΔI L(II) and the coil current I in state IV L The change in ΔI L(IV) becomes very small and the ripple loss becomes negligible.

[0049] In the second mode, the reference phases SW1 and SW2 and the control phases SW3 and SW4 are switched at the same cycle T, respectively, and phase shift control can be performed to change the phase difference φd therebetween.

[0050] Figure 7 shows the relationship between the phase difference φd and the output current I OUT By changing the phase difference φd, the output current I OUT can be controlled, and thus the output voltage V OUT V IN It can be varied in the vicinity of / 2.

[0051] Figure 8 shows the inductor current I under heavy and light load conditions for a resonant switching converter operating in the second mode. L As mentioned above, zero voltage switching is possible in the second mode, but for this to happen, the coil current I1 when transitioning to state II and the coil current I2 when transitioning to state III must both be greater than 0. In other words, the conditions for zero voltage switching are I1>0, I2>0. This condition is met under heavy load conditions.

[0052] However, under light load conditions, I1<0, the condition for zero voltage switching is no longer satisfied, and efficiency drops. The first mode is selected under light load conditions when the efficiency drops in the second mode.

[0053] The operation of the first mode will be described below. As described above, in the first mode, states φ1 to φ4 are repeated.

[0054] 9 is an equivalent circuit diagram of the resonant switched capacitor converter 100 in state φ1. In state φ1, Vn1=V IN -Vc Vn3=V OUT When the voltage across the flying capacitor C1 is Vc, the voltage across the inductor L1 is ΔV L(I) teeth, ΔV L(I) =V IN -Vc-V OUT This becomes: Therefore, in state I, the coil current I flows through inductor L1. L The slope of (V IN -Vc-V OUT ) / L This becomes:

[0055] 10 is an equivalent circuit diagram of the resonant switched capacitor converter 100 in the first mode in state φ2. In state φ2, Vn1=V OUT Vn3=0V When the voltage across the flying capacitor C1 is Vc, the voltage across the inductor L1 is ΔV L(II) teeth, ΔV L(II) =V OUT It becomes -Vc. Therefore, in state φ2, the coil current I flowing through inductor L1 L The slope of (V OUT -Vc) / L This becomes:

[0056] 11 is an equivalent circuit diagram of the state φ3 of the first mode of the resonant switched capacitor converter 100. In the state φ3, the switching nodes n1 and n3 are at high impedance.

[0057] 12 is a time chart illustrating the operation of the first mode of the resonant switched capacitor converter 100. In FIG. L In the first state φ1, the coil current I L The change in ΔI L(φ1) is expressed by the following formula: ΔI L(φ1) =(V IN -Vc-V OUT ) / L×t on

[0058] In the subsequent second state φ2, the coil current I L The change in ΔI L(φ2) is expressed by the following formula: ΔI L(φ2) =(V OUT -Vc) / L×t off In the second state φ2, the coil current I L decreases to zero.

[0059] Then, the state transitions to the third state φ3. During the third state φ3, the coil current I L remains unchanged and remains zero.

[0060] The above is the operation of the first mode. In the first mode, the length t HiZ By changing the output voltage V OUT It is possible to control the length t of the third state φ3 to be constant under light load conditions. HiZ When the switching frequency is longer, the switching loss can be reduced, which makes it possible to increase the efficiency at light loads compared to when operating in the second mode.

[0061] Fig. 13 is a circuit diagram showing a configuration example (200A) of the controller IC 200. Fig. 13 shows only the parts related to the first mode.

[0062] The feedback pin FB of the controller IC200A is connected to the output voltage V OUT Feedback signal V according to FB is fed back. For example, the output voltage V OUT The signal is divided by resistors R1 and R2 and is used as the feedback signal V FB Alternatively, the feedback pin FB may be directly connected to the output line 104, and the output voltage V OUT The feedback signal V FB It may also be possible to use the following.

[0063] The comparator 240 receives the feedback signal V FB is the threshold voltage V TH Compared with the feedback signal V FB is the threshold voltage V TH When the voltage drops to 0 V, the turn-on signal TURN_ON is asserted. The one-shot circuit 242 is triggered by the assertion of the turn-on signal TURN_ON to output a pulse signal Sp that remains high for a predetermined period of time. The state control unit 220 remains in the first state φ1 during the high interval of the pulse signal Sp, and transitions to the second state φ2 when the pulse signal Sp transitions to low.

[0064] The current detection pin CS of the controller IC200A detects the coil current I in the second state φ2 of the first mode. LFor example, the coil current I L When a sense resistor is provided on the path of the current sense pin CS, the current sense pin CS is connected to the sense resistor. As shown in FIG. 10, in the second state φ2, the coil current I L Therefore, the coil current I L Therefore, when monitoring the drain-source voltage of the fourth switch SW4, the current sense pin CS may be connected to the drain of the fourth switch SW4, i.e., the switching node n3.

[0065] The zero current detection circuit 244 detects the coil current I L becomes zero, the state control unit 220 asserts the zero-crossing detection signal ZC. In response to the assertion of the zero-crossing detection signal ZC, the state control unit 220 transitions to the third state φ3.

[0066] FIG. 14 is an operation waveform diagram of the controller IC200A of FIG. 13. In FIG. 14, the charging current I CHG , output voltage V OUT , the turn-on signal TURN_ON, the pulse signal Sp, and the zero current detection signal ZC are shown. The charging current I to the output capacitor C2 CHG is the coil current I L corresponds to the absolute value of

[0067] During the high section of the one-shot pulse Sp from time t0 to t1, the first state φ1 is reached, and the output current I OUT increases. Charging current I CHG The capacitor C2 is charged by the OUT will rise.

[0068] In the second state φ2, the charging current I CHG During the second state φ2, the output voltage V OUT At time t2, the coil current I LWhen the zero current detection signal ZC becomes zero, the state transitions to the third state φ3. In the third state φ3, the output capacitor C2 flows through the output current I OUT Since the output voltage V OUT At time t3, the feedback signal V FB is the threshold voltage V TH When the voltage drops to , the turn-on signal TURN_ON is asserted, the pulse signal Sp becomes high, and the state returns to the first state φ1.

[0069] The controller IC 200A repeats the above operation. According to this controller IC 200A, the feedback signal V FB , the threshold voltage V TH The voltage can be stabilized within a voltage range with a lower limit of

[0070] (Variation) The above-described embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of the components and the processing steps. Such modifications will be described below.

[0071] In the embodiment, the controller IC 200 is described as being switchable between the first mode and the second mode, but this is not a limitation. The controller IC 200 may be designed to operate only in the first mode. Alternatively, the controller IC 200 may be switchable between the first mode and a third mode that performs a control method different from the second mode.

[0072] In the embodiment, the switches SW1 to SW4 are configured by transistors, but some of the switches may be diodes.

[0073] (Application) 15 is a diagram showing an example of an electronic device 700 including a resonant switched capacitor converter 100. A suitable example of the electronic device 700 is a server. The server 700 includes an internal circuit 710 and a power supply circuit 720. The internal circuit 710 may include a CPU (Central Processing Unit), a memory, a LAN (Local Area Network) interface circuit, a DC / DC converter that steps down a voltage of 12 V, and the like.

[0074] Some servers operate on a 24V power supply, and their internal circuit 710 includes a block that operates on 12V. In this case, a power supply circuit 720 that steps down the 24V power supply voltage to 12V is required. The resonant switched capacitor converter 100 with a gain of 1 / 2 described above can be suitably used for such a power supply circuit 720.

[0075] Furthermore, in recent years, there has been a growing trend to increase the power supply voltage to 48 V in order to reduce the current flowing through electric wires. In this case, the resonant switched capacitor converter 100 with a gain of 1 / 2 can be suitably used to supply a power supply voltage to the internal circuit 710 that operates at 24 V. Alternatively, two resonant switched capacitor converters 100 according to the embodiment can be connected in series to generate a power supply voltage of 12 V and supply it to the internal circuit that operates at 12 V.

[0076] The electronic device 700 is not limited to a server, but may also be an in-vehicle device. While conventional automobile batteries are mainly 12V or 24V, hybrid vehicles may employ 48V systems, which also require a power supply circuit to convert the 48V battery voltage to 24V. In such cases, the 1 / 2 resonant switched capacitor converter 100 can be suitably used.

[0077] Alternatively, the electronic device 700 may be an industrial device, an OA (Office Automation) device, or a consumer device such as an audio device.

[0078] The embodiments are merely examples, and it will be understood by those skilled in the art that there are various variations in the combination of each component and each treatment process, and that such variations are also included in the present disclosure and can constitute the scope of the present invention. [Explanation of symbols]

[0079] 100 Resonant Switched Capacitor Converter 102 input lines 104 output lines 106 LC resonant circuit 108 Ground Line 200 Controller IC 210 Drive circuit 220 State control section 230 Light Load Detection Circuit SW1 First switch SW2 Second switch SW3 Third switch SW4 4th switch C1, C2 capacitors L1 inductor 240 Comparator 242 One-shot circuit 244 Zero Current Detection Circuit

Claims

1. 1. A controller circuit for a resonant switched capacitor converter, comprising: The resonant switched capacitor converter comprises: a first switch and a second switch connected in series between the input line and the output line; a third switch and a fourth switch connected in series between the output line and a ground line; a capacitor and an inductor connected in series across the second switch and the third switch; Equipped with The controller circuit is capable of switching between a first mode and a second mode according to a load state, and in the first mode: a first state φ1 in which the first switch and the third switch are on and the second switch and the fourth switch are off; a second state φ2 in which the second switch and the fourth switch are on and the first switch and the third switch are off; a third state φ3 in which the first switch, the second switch, the third switch, and the fourth switch are off; are repeated in sequence, and in the second mode, a state I in which the first switch and the fourth switch are on and the second switch and the third switch are off; a state II in which the first switch and the third switch are on and the second switch and the fourth switch are off; a state III in which the second switch and the third switch are on and the first switch and the fourth switch are off; a state IV in which the second switch and the fourth switch are on and the first switch and the third switch are off; Repeat in order, The controller circuit In the second mode, when the coil current I 1 at the time of transition to the state II and the coil current I 2 at the time of transition to the state III are both greater than 0, control is performed in the second mode; a controller circuit that performs control in the first mode when the coil current I 1 is I 1 <0 upon transition to state II;

2. 2. The controller circuit of claim 1, wherein while operating in the first mode, the controller circuit transitions to the first state φ1 when the output voltage of the resonant switched capacitor converter drops to a threshold voltage in the third state φ3.

3. 3. A controller circuit as claimed in claim 1 or 2, wherein during operation in the first mode, the length of the first state φ1 is fixed.

4. 4. The controller circuit according to claim 1, wherein when the current in the inductor becomes zero in the second state φ2 while operating in the first mode, the controller circuit transitions to the third state φ3.

5. The controller circuit according to claim 1, further comprising a zero current detection circuit that asserts a zero-cross detection signal when the coil current I L becomes zero in the second state φ2.

6. 6. The controller circuit according to claim 1, which is monolithically integrated on a single semiconductor substrate.

7. A resonant switched capacitor converter comprising a controller circuit according to any one of claims 1 to 6.

8. An electronic device comprising the resonant switched capacitor converter of claim 7.

Images