Stepped switched capacitor conversion circuit and method

Abstract

The invention relates to a step-type switched capacitor conversion circuit and method. The conversion circuit comprises a step determination module, a switch control module, an output capacitor connected between a current output end and the ground, and at least one flying capacitor. One end of the flying capacitor is connected between the current input end and the current output end, and the other end of the flying capacitor is grounded through a switch and connected between the current output end and the output capacitor through another switch; the step determination module is used for determining the number of steps according to the proportion of the input voltage to the output voltage, and the number of the steps is a positive integer; and the switch control module controls the on-off of each switch according to the step number, and further controls the charging and discharging process of the corresponding flying capacitor, so that the voltage of the last flying capacitor is equal to the output voltage. According to the invention, through a multi-step switched capacitor control mode, the step voltage change of the flying capacitor is utilized, and the efficient conversion of the fixed integer proportion and / or the non-integer proportion of the input and output voltage is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and more particularly to a ladder-type switched capacitor conversion circuit and method. Background Art

[0002] As a highly efficient power conversion device, switched capacitor converters are widely used in various power management systems. Their primary function is to convert between different voltage levels to meet the power supply needs of various electronic devices. Traditional switched capacitor converters typically use a fixed duty cycle control method, such as the common use of two 50% duty cycle PWM pulse-width modulation signals to achieve voltage conversion. This traditional method has many limitations in practical applications. For example, when implementing non-integer ratio voltage regulation, it is difficult to flexibly adjust, requiring complex circuit transformations and additional design work. Furthermore, it is difficult to achieve ideal regulation accuracy and efficiency, resulting in limited overall performance. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a ladder-type switched capacitor conversion circuit to address the above-mentioned defect of the prior art that it is difficult to achieve non-integer ratio voltage regulation.

[0004] The technical solution adopted by the present invention to solve the technical problem is: providing a ladder-type switched capacitor conversion circuit, including a ladder determination module, a switch control module, an output capacitor Cout and at least one flying capacitor C;

[0005] The current input end is connected to the voltage output end through at least two switching tubes in sequence, and the voltage output end is also grounded through the output capacitor Cout;

[0006] One end of the flying capacitor C is connected to the common point of two adjacent switching tubes between the voltage input terminal and the voltage output terminal, and the other end is grounded via a switching tube and is also connected to the common point of the output capacitor and the voltage output terminal via another switch;

[0007] The step determination module is used to determine the number of steps according to the ratio of the input voltage to the output voltage, wherein the number of steps is a positive integer;

[0008] When the ratio of the input voltage to the output voltage is a non-integer, the switch control module controls the charging and discharging process of the flying capacitor C, and determines the voltage difference between adjacent flying capacitors according to the number of steps, the input voltage, and the output voltage, so that the voltage of the last flying capacitor is equal to the output voltage or the input voltage.

[0009] In one embodiment, when the ratio of the input voltage to the output voltage is an integer, the switch control module controls the charging and discharging process of the flying capacitor so that the voltage difference between adjacent flying capacitors is equal to the output voltage or the input voltage.

[0010] In one embodiment, the system includes a first flying capacitor C1, a first switch transistor SW1, a second switch transistor SW2, a third switch transistor SW3, a fourth switch transistor SW4, and an output capacitor Cout connected between the current output terminal and the ground.

[0011] The current output end and the current output end are connected in sequence through the first switch tube SW1 and the fourth switch tube SW4. One end of the first flying capacitor C1 is connected between the first switch tube SW1 and the fourth switch tube SW4, and the other end is grounded through the second switch tube SW2, and is connected to a common point between the current output end and the output capacitor Cout through the third switch tube SW3.

[0012] The switch control module is connected to the control terminals of the first switch tube SW1 , the second switch tube SW2 , the third switch tube SW3 , and the fourth switch tube SW4 , respectively.

[0013] In one embodiment, the device further includes a second flying capacitor C2, a fifth switch transistor SW5, a sixth switch transistor SW6, and a seventh switch transistor SW7;

[0014] The fourth switch transistor SW4 is connected to the current output terminal through the seventh switch transistor SW7. One end of the second flying capacitor C2 is connected to a common point between the fourth switch transistor SW4 and the seventh switch transistor SW7. The other end of the second flying capacitor C2 is grounded through the fifth switch transistor SW5 and connected to a common point between the current output terminal and the output capacitor Cout through the sixth switch transistor SW6.

[0015] The switch control module is connected to the control terminals of the fifth switch tube SW5 , the sixth switch tube SW6 , and the seventh switch tube SW7 , respectively.

[0016] In one embodiment, the invention further includes a third flying capacitor C3, an eighth switch transistor SW8, a ninth switch transistor SW9 and a tenth switch transistor SW10;

[0017] The seventh switch transistor SW7 is connected to the current output terminal through the tenth switch transistor SW10. One end of the third flying capacitor C3 is connected to a common point between the seventh switch transistor SW7 and the tenth switch transistor SW10. The other end of the third flying capacitor C3 is grounded through the eighth switch transistor SW8 and connected to a common point between the current output terminal and the output capacitor Cout through the ninth switch transistor SW9.

[0018] The switch control module is connected to the control terminals of the eighth switch tube SW8 , the ninth switch tube SW9 , and the tenth switch tube SW10 , respectively.

[0019] In one embodiment, the switch control module controls the flying capacitor charging process and the voltage balancing process so that the voltage of the output capacitor Cout is stably equal to the output voltage.

[0020] In one embodiment, the number of steps is four;

[0021] The flying capacitor performs the following in each control cycle:

[0022] First working state: respectively controlling the first switch SW1, the third switch SW3, the fifth switch SW5, the seventh switch SW7, and the ninth switch SW9 to be turned on, and respectively controlling the second switch SW2, the fourth switch SW4, the sixth switch SW6, the eighth switch SW8, and the tenth switch SW10 to be turned off;

[0023] Second working state: respectively controlling the second switch SW2, the fourth switch SW4, and the sixth switch SW6 to be turned on, and respectively controlling the first switch SW1, the third switch SW3, the fifth switch SW5, the seventh switch SW7, the eighth switch SW8, the ninth switch SW9, and the tenth switch SW10 to be turned off;

[0024] Third working state: respectively controlling the second switch SW2, the fourth switch SW4, the sixth switch SW6, the eighth switch SW8, and the tenth switch SW10 to be turned on, and respectively controlling the first switch SW1, the third switch SW3, the fifth switch SW5, the seventh switch SW7, and the ninth switch SW9 to be turned off;

[0025] Fourth working state: the fifth switch SW5, the seventh switch SW7, and the ninth switch SW9 are respectively turned on, and the first switch SW1, the second switch SW2, the third switch SW3, the fourth switch SW4, the sixth switch SW6, the eighth switch SW8, and the tenth switch SW10 are respectively turned off;

[0026] The flying capacitor charging process is achieved by controlling the first working state; the flying capacitor voltage balancing process is achieved by controlling the second working state, the third working state and the fourth working state, wherein the execution order of the first working state, the second working state, the third working state and the fourth working state can be adjusted arbitrarily.

[0027] In one embodiment, the switch tube is any one of a silicon-based MOSFET device, a silicon carbide device, or a gallium nitride device.

[0028] In one embodiment, the switch control module includes:

[0029] The PWM generator is used to generate pulse width modulation signals to control the on and off of each switch tube.

[0030] The present application further provides a ladder-type switched capacitor conversion method, which is used in any of the above-mentioned ladder-type switched capacitor conversion circuits. The ladder-type switched capacitor conversion method includes:

[0031] S1: Determine the number of steps according to the ratio of the input voltage to the output voltage, where the number of steps is a positive integer;

[0032] S2: when the ratio of the input voltage to the output voltage is a non-integer, determining a voltage difference between adjacent flying capacitors according to the number of steps, the input voltage, and the output voltage;

[0033] S3: controlling the charging and discharging process of the flying capacitor according to the voltage difference between the adjacent flying capacitors, so that the voltage of the last flying capacitor is equal to the output voltage or the input voltage.

[0034] The beneficial effect of the present invention is that the present application provides a step-type switched capacitor conversion circuit, including a step determination module, a switch control module, an output capacitor Cout, and at least one flying capacitor; the current input end is connected to the voltage output end through at least two switch tubes in sequence, and the voltage output end is also grounded through the output capacitor Cout; one end of the flying capacitor is connected to the common point of two adjacent switch tubes between the voltage input end and the voltage output end, and the other end is grounded through a switch tube and is also connected to the common point of the output capacitor and the voltage output end through another switch; the step determination module is used to determine the number of steps according to the ratio of the input voltage to the output voltage, wherein the number of steps is a positive integer; when the ratio of the input voltage to the output voltage is not an integer, the switch control module controls the charging and discharging process of the flying capacitor, and determines the voltage difference between adjacent flying capacitors according to the number of steps, the input voltage, and the output voltage, so that the voltage of the last flying capacitor is equal to the output voltage or the input voltage. The present application uses a multi-step switched capacitor control method and utilizes the step voltage change of the flying capacitor to achieve efficient conversion of non-integer ratios of input and output voltages, thereby improving the flexibility and accuracy of voltage conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0036] Figure 1 1. A schematic structural diagram of a circuit embodiment of a ladder-type switched capacitor conversion circuit;

[0037] Figure 2 This is a schematic structural diagram of another embodiment of a ladder-type switched capacitor conversion circuit. DETAILED DESCRIPTION

[0038] The present application is further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted in different circumstances, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0039] like Figure 1 As shown, Figure 1 This is a logic diagram of a ladder-type switched capacitor conversion circuit.

[0040] The technical solution adopted by the present invention to solve its technical problem is: constructing a step-type switched capacitor conversion circuit, including a step determination module, a switch control module, an output capacitor Cout, and at least one flying capacitor C; the current input end is connected to the voltage output end through at least two switching tubes in sequence, and the voltage output end is also grounded through the output capacitor Cout; one end of the flying capacitor C is connected to the common point of two adjacent switching tubes between the voltage input end and the voltage output end, and the other end is grounded through a switching tube and is also connected to the common point of the output capacitor and the voltage output end through another switch; the step determination module is used to determine the number of steps based on the ratio of the input voltage to the output voltage, wherein the number of steps is a positive integer; when the ratio of the input voltage to the output voltage is not an integer, the switch control module controls the charging and discharging process of the flying capacitor C, and determines the voltage difference between adjacent flying capacitors based on the number of steps, the input voltage, and the output voltage, so that the voltage of the last flying capacitor is equal to the output voltage or the input voltage.

[0041] It should be noted that in the process of increasing the steps, the voltage across the flying capacitor is always maintained at the state of input voltage minus output voltage. The voltage of each step decreases in sequence until the flying capacitor voltage at the last step is equal to the output voltage. By applying the principle that the voltage of the series capacitor is inversely proportional to the capacity, the voltage of different steps is adjusted, and the output voltage can be accurately adjusted to a non-integer multiple ratio relative to the input voltage, thereby meeting diverse power management requirements and improving the flexibility and adaptability of the circuit. At the same time, at least two switching tubes are included, where the number of switching tubes can be two or more, and can be odd or even.

[0042] Furthermore, when the ratio of the input voltage to the output voltage is an integer, the switch control module controls the charging and discharging process of the flying capacitor so that the voltage difference between adjacent flying capacitors is equal to the output voltage or the input voltage.

[0043] like Figure 2 As shown, further, it includes a first flying capacitor C1, a first switch tube SW1, a second switch tube SW2, a third switch tube SW3, a fourth switch tube SW4 and the first flying capacitor C1 and an output capacitor Cout connected between the current output end and the ground; the current output end and the current output end are connected in sequence through the first switch tube SW1 and the fourth switch tube SW4, one end of the first flying capacitor C1 is connected between the first switch tube SW1 and the fourth switch tube SW4, and the other end is grounded through the second switch tube SW2, and is connected to the common point of the current output end and the output capacitor Cout through the third switch tube SW3; the switch control module is respectively connected to the control ends of the first switch tube SW1, the second switch tube SW2, the third switch tube SW3 and the fourth switch tube SW4.

[0044] When the ratio of the input voltage to the output voltage is non-integer, the switch control module controls the charging and discharging process of the flying capacitor, determines the voltage difference between adjacent flying capacitors based on the number of steps, input voltage, and output voltage, and adjusts the charging and discharging time ratio of each flying capacitor so that the voltage of the output capacitor Cout is equal to the output voltage.

[0045] It should be noted that when the input-output voltage change ratio is 2, the voltage across the first flying capacitor C1 is always equal to the input voltage minus the output voltage. When the capacitance value of the first flying capacitor C1 is equal to that of the output capacitor Cout, the voltage across Cout will stabilize at half the input voltage. By adjusting the capacitance ratio of the first flying capacitor C1 and Cout, the voltage across Cout can be made higher than or equal to half of the input voltage, thereby achieving preliminary regulation of the output voltage. In order to achieve more precise voltage control and current balance, switching tubes and auxiliary capacitors are introduced into the circuit, which work together to act on the charging and discharging process of C1 and Cout.

[0046] This single-step circuit design is particularly suitable for scenarios with a staircase number of around two. When a larger voltage range needs to be handled, the circuit can be expanded by adding more steps. In a multi-step design, each additional step introduces a new flying capacitor, while the voltage across C1 remains the same as the input voltage minus the output voltage. As the number of steps increases, the voltage of each subsequent step gradually decreases until the flying capacitor voltage of the last step is equal to the output voltage, thus achieving voltage conversion.

[0047] To achieve a non-integer multiple of the output voltage, the circuit design exploits the characteristic of series capacitors: the voltage distribution across the capacitors is inversely proportional to the capacitance. By adjusting the capacitance ratio of the flying capacitors in different steps, the voltage value of each step can be changed, thereby making the output voltage a non-integer multiple of the input voltage. This design not only increases the flexibility of voltage regulation but also ensures efficient operation of the circuit in a variety of application scenarios.

[0048] Furthermore, the ladder-type switched capacitor conversion circuit further includes a second flying capacitor C2, a fifth switch tube SW5, a sixth switch tube SW6, and a seventh switch tube SW7;

[0049] The fourth switch SW4 is connected to the current output terminal via the seventh switch SW7. One end of the second flying capacitor C2 is connected to a common point between the fourth switch SW4 and the seventh switch SW7. The other end of the second flying capacitor C2 is grounded via the fifth switch SW5 and connected to a common point between the current output terminal and the output capacitor Cout via the sixth switch SW6.

[0050] The switch control module is connected to the control terminals of the fifth switch tube SW5 , the sixth switch tube SW6 and the seventh switch tube SW7 respectively.

[0051] Furthermore, the ladder-type switched capacitor conversion circuit further includes a third flying capacitor C3, an eighth switch tube SW8, a ninth switch tube SW9 and a tenth switch tube SW10;

[0052] The seventh switch SW7 is connected to the current output terminal via the tenth switch SW10. One end of the third flying capacitor C3 is connected to a common point between the seventh switch SW7 and the tenth switch SW10. The other end of the third flying capacitor C3 is grounded via the eighth switch SW8 and connected to a common point between the current output terminal and the output capacitor Cout via the ninth switch SW9.

[0053] The switch control module is connected to the control terminals of the eighth switch tube SW8 , the ninth switch tube SW9 and the tenth switch tube SW10 respectively.

[0054] Furthermore, the switch control module controls the flying capacitor charging process and the voltage balancing process so that the voltage of the output capacitor Cout is stably equal to the output voltage.

[0055] Furthermore, the number of steps is four;

[0056] The flying capacitor performs the following in each control cycle:

[0057] First working state: respectively control the first switch SW1, the third switch SW3, the fifth switch SW5, the seventh switch SW7, and the ninth switch SW9 to be turned on, and respectively control the second switch SW2, the fourth switch SW4, the sixth switch SW6, the eighth switch SW8, and the tenth switch SW10 to be turned off;

[0058] Second working state: the second switch SW2, the fourth switch SW4 and the sixth switch SW6 are respectively turned on, and the first switch SW1, the third switch SW3, the fifth switch SW5, the seventh switch SW7, the eighth switch SW8, the ninth switch SW9 and the tenth switch SW10 are respectively turned off;

[0059] The third working state: the second switch SW2, the fourth switch SW4, the sixth switch SW6, the eighth switch SW8, and the tenth switch SW10 are respectively turned on, and the first switch SW1, the third switch SW3, the fifth switch SW5, the seventh switch SW7, and the ninth switch SW9 are respectively turned off;

[0060] Fourth working state: the fifth switch SW5, the seventh switch SW7, and the ninth switch SW9 are respectively turned on, and the first switch SW1, the second switch SW2, the third switch SW3, the fourth switch SW4, the sixth switch SW6, the eighth switch SW8, and the tenth switch SW10 are respectively turned off;

[0061] The flying capacitor charging process is achieved by controlling the first working state; the flying capacitor voltage balancing process is achieved by controlling the second working state, the third working state and the fourth working state, wherein the execution order of the first working state, the second working state, the third working state and the fourth working state can be adjusted arbitrarily.

[0062] In a specific embodiment, the step voltages of N flying capacitors are obtained by turning on and off the switch. If it is an ideal integer, the flying capacitors are equal and the voltage difference between adjacent steps is Vout. The output voltage is:

[0063] Vout = Vin / N;

[0064] The flying capacitor voltage at the first step is:

[0065] VC1=Vin-Vout, where VC1 is the first flying capacitor voltage, Vin is the input voltage, and Vout is the output voltage.

[0066] The flying capacitor voltage at the second step is:

[0067] VC2=Vin-2*Vout, where VC2 is the first flying capacitor voltage, Vin is the input voltage, and Vout is the output voltage.

[0068] The flying capacitor voltage of the mth step is:

[0069] VCm=Vin-m*Vout, where VCm is the first flying capacitor voltage, Vin is the input voltage, and Vout is the output voltage.

[0070] The voltage of the nth flying capacitor at the last step is:

[0071] VCn=Vout, where VCn is the first flying capacitor voltage, Vin is the input voltage, and Vout is the output voltage.

[0072] In one embodiment, the preset number is 1. If the output voltage and the input voltage are integers, in the first case, the input voltage is greater than the output voltage, and the number of steps is the quotient of the input voltage divided by the output voltage rounded down minus 1. In the second case, the output voltage is greater than the input voltage, and the number of steps is the quotient of the output voltage divided by the input voltage rounded down minus 1. The step determination module is responsible for determining the number of steps based on the ratio of the input voltage Vin to the output voltage Vout. When the input is 48V and the output is 12V, the input voltage is greater than the output voltage, and the ratio is 48 / 12=4. The number of steps is 4-1=3. The specific working process is as follows:

[0073] First step output: 48-12=36V;

[0074] Second step output: 48-24=24V;

[0075] The third step output: 48-36=12V.

[0076] In one embodiment, when the input voltage is greater than the output voltage, the number of steps is equal to the quotient obtained by dividing the input voltage by the output voltage and rounding it down minus 1; when the output voltage is greater than the input voltage, the number of steps is equal to the quotient obtained by dividing the output voltage by the input voltage and rounding it down minus 1.

[0077] In another embodiment, if the ratio of the output voltage to the input voltage is a non-integer, the step determination module determines the number of steps by rounding down or rounding up the ratio of the input voltage to the output voltage. Specifically, when the ratio of the input voltage to the output voltage is a non-integer, the step determination module may select to round down or round up to determine the number of steps to accommodate different design needs and performance requirements.

[0078] When the input is 48V and the output is 10V, the ratio is 48 / 10 = 4.8. The step determination module can choose to round down and subtract 1 or round up and subtract 1 to determine the number of steps. Round down and subtract 1: the number of steps is 4-1 = 3. It should be noted that when the input voltage is greater than the output voltage, the voltage difference between adjacent steps = input voltage / N+1*output voltage. For example, 12 = 48 / 40. The specific working process is as follows:

[0079] First step output: 48-12=36V;

[0080] Second step output: 48-24=24V;

[0081] The third step output: 48-36=12V;

[0082] Round up and subtract 1: the number of steps is 5-1=4. The specific working process is as follows:

[0083] First step output: 48-9.6=38.4V;

[0084] Second step output: 48-19.2=28.8V;

[0085] The third step output: 48-28.8=19.2V;

[0086] Fourth step output: 48-38.4=9.6V;

[0087] To balance the overall voltage and achieve non-integer voltage regulation, the circuit introduces additional switches to dissipate or store additional energy. By controlling the on and off of these switches, they absorb some of the voltage drop, thereby balancing the circuit voltage and ensuring that the final output voltage remains stable at the set output voltage. This approach achieves non-integer voltage regulation with minimal power loss.

[0088] Furthermore, the switch control module is used to control the on and off time of each switch tube according to a preset PWM duty cycle in each working state.

[0089] Furthermore, the switch tube is any one of a silicon-based MOSFET device, a silicon carbide device or a gallium nitride device.

[0090] The present application also provides a step-type switched capacitor conversion method, which can be used in any of the above conversion circuits. The conversion method includes:

[0091] S1: The number of steps is determined according to the ratio of input voltage to output voltage. The number of steps is a positive integer.

[0092] S2: When the ratio of the input voltage to the output voltage is non-integer, the voltage difference between adjacent flying capacitors is determined based on the number of steps, the input voltage, and the output voltage;

[0093] S3: Control the charging and discharging process of the flying capacitor according to the voltage difference between adjacent flying capacitors, so that the voltage of the last flying capacitor is equal to the output voltage or the input voltage.

[0094] In one embodiment, a step-type switched capacitor control circuit comprises a step determination module, a switch control module, and at least one flying capacitor. One end of the flying capacitor is connected between the current input terminal and the current output terminal, and the other end is grounded through a switch and connected to the current output terminal through another switch. The step determination module determines the number of steps based on the ratio of the input voltage Vin to the output voltage Vout, and the number is a positive integer. The switch control module controls the on and off of each switch according to the determined number of steps, thereby regulating the charging and discharging process of the flying capacitor to ensure that the voltage of the last flying capacitor is equal to the output voltage.

[0095] Integer Ratio: When the ratio of the input voltage to the output voltage is an integer, the switch control module controls the charging and discharging of the flying capacitors so that the voltage difference between adjacent flying capacitors equals the output voltage. For example, if the input voltage is 48V and the output voltage is 12V, the number of steps is 3. In this case, the output voltages of each step are 36V, 24V, and 12V, respectively.

[0096] Non-integer ratio case: When the ratio of the input voltage to the output voltage is a non-integer, the step determination module determines the number of steps based on the ratio of the input voltage to the output voltage, rounding down or rounding up. The switch control module determines the voltage difference of adjacent flying capacitors based on the number of steps, input voltage and output voltage, and adjusts the proportion of the charge and discharge time of each flying capacitor so that the voltage of the output capacitor is equal to the output voltage. For example, when the input voltage is 48V and the output voltage is 10V, the ratio is 4.8. At this time, the step determination module can choose to round down and subtract 1 to make the number of steps 3 or round up and subtract 1 to make the number of steps 4. In the case of rounding down, the output voltages of each step are 36V, 24V and 12V respectively; where the voltage difference between adjacent steps V = input voltage Vin / number of steps N+1, and in the case of rounding up, the output voltages of each step are 38.4V, 28.8V, 19.2V and 9.6V respectively.

[0097] To balance the overall voltage and achieve non-integer voltage regulation, the circuit introduces additional switches to dissipate or store additional energy. By controlling the on and off of these switches, they absorb a portion of the voltage drop, thereby balancing the circuit voltage and ensuring that the final output voltage is stable and equal to the set output voltage. For example, in the case of non-integer voltage regulation, by controlling the ratio of the flying capacitor capacitance, the output voltage of the final step can be stabilized to be equal to the set output voltage. This allows for integer and / or non-integer voltage regulation, ensuring output voltage stability and accuracy.

[0098] It is understandable that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, all of which fall within the scope of protection of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of coverage of the claims of the present invention.

Claims

1. A ladder-type switched capacitor conversion circuit, characterized in that: It includes a step determination module, a switch control module, an output capacitor (Cout) and at least one flying capacitor (C); The current input end is connected to the voltage output end in sequence through at least two switching tubes, and the voltage output end is also grounded through the output capacitor (Cout); One end of the flying capacitor (C) is connected to the common point of two adjacent switching tubes between the voltage input terminal and the voltage output terminal, and the other end is grounded via a switching tube and is also connected to the common point of the output capacitor and the voltage output terminal via another switch; The step determination module is used to determine the number of steps according to the ratio of the input voltage to the output voltage, wherein the number of steps is a positive integer; When the ratio of the input voltage to the output voltage is non-integer, the switch control module controls the charging and discharging process of the flying capacitor (C), and determines the voltage difference between adjacent flying capacitors based on the number of steps, the input voltage, and the output voltage, so that the voltage of the last flying capacitor is equal to the output voltage or the input voltage.

2. The ladder-type switched capacitor conversion circuit according to claim 1, wherein: When the ratio of the input voltage to the output voltage is an integer, the switch control module controls the charging and discharging process of the flying capacitor so that the voltage difference between adjacent flying capacitors is equal to the output voltage or the input voltage.

3. The ladder-type switched capacitor conversion circuit according to claim 1, characterized in that: It includes a first flying capacitor (C1), a first switch tube (SW1), a second switch tube (SW2), a third switch tube (SW3), a fourth switch tube (SW4), and an output capacitor (Cout) connected between the current output terminal and the ground and the first flying capacitor (C1); The current output end and the current output end are connected in sequence through the first switch tube (SW1) and the fourth switch tube (SW4); one end of the first flying capacitor (C1) is connected between the first switch tube (SW1) and the fourth switch tube (SW4); the other end is grounded through the second switch tube (SW2) and connected to a common point between the current output end and the output capacitor (Cout) through the third switch tube (SW3); The switch control module is respectively connected to the control ends of the first switch tube (SW1), the second switch tube (SW2), the third switch tube (SW3) and the fourth switch tube (SW4).

4. The ladder-type switched capacitor conversion circuit according to claim 3, characterized in that: It also includes a second flying capacitor (C2), a fifth switch tube (SW5), a sixth switch tube (SW6), and a seventh switch tube (SW7); The fourth switch tube (SW4) is connected to the current output end through the seventh switch tube (SW7); one end of the second flying capacitor (C2) is connected to a common point between the fourth switch tube (SW4) and the seventh switch tube (SW7); the other end is grounded through the fifth switch tube (SW5) and connected to a common point between the current output end and the output capacitor (Cout) through the sixth switch tube (SW6); The switch control module is respectively connected to the control ends of the fifth switch tube (SW5), the sixth switch tube (SW6) and the seventh switch tube (SW7).

5. The ladder-type switched capacitor conversion circuit according to claim 4, characterized in that: It also includes a third flying capacitor (C3), an eighth switch tube (SW8), a ninth switch tube (SW9) and a tenth switch tube (SW10); The seventh switch tube (SW7) is connected to the current output end through the tenth switch tube (SW10); one end of the third flying capacitor (C3) is connected to a common point between the seventh switch tube (SW7) and the tenth switch tube (SW10); the other end is grounded through the eighth switch tube (SW8) and connected to a common point between the current output end and the output capacitor (Cout) through the ninth switch tube (SW9); The switch control module is respectively connected to the control ends of the eighth switch tube (SW8), the ninth switch tube (SW9) and the tenth switch tube (SW10).

6. The ladder-type switched capacitor conversion circuit according to claim 5, characterized in that: The switch control module controls the flying capacitor charging process and the voltage balancing process so that the voltage of the output capacitor (Cout) is stably equal to the output voltage.

7. The ladder-type switched capacitor conversion circuit according to claim 6, characterized in that: The number of steps is four; The flying capacitor performs the following in each control cycle: First working state: respectively controlling the first switch tube (SW1), the third switch tube (SW3), the fifth switch tube (SW5), the seventh switch tube (SW7), and the ninth switch tube (SW9) to be turned on, and respectively controlling the second switch tube (SW2), the fourth switch tube (SW4), the sixth switch tube (SW6), the eighth switch tube (SW8), and the tenth switch tube (SW10) to be turned off; Second working state: respectively controlling the second switch tube (SW2), the fourth switch tube (SW4), and the sixth switch tube (SW6) to be turned on, and respectively controlling the first switch tube (SW1), the third switch tube (SW3), the fifth switch tube (SW5), the seventh switch tube (SW7), the eighth switch tube (SW8), the ninth switch tube (SW9), and the tenth switch tube (SW10) to be turned off; A third working state: respectively controlling the second switch tube (SW2), the fourth switch tube (SW4), the sixth switch tube (SW6), the eighth switch tube (SW8), and the tenth switch tube (SW10) to be turned on, and respectively controlling the first switch tube (SW1), the third switch tube (SW3), the fifth switch tube (SW5), the seventh switch tube (SW7), and the ninth switch tube (SW9) to be turned off; Fourth working state: respectively controlling the fifth switch tube (SW5), the seventh switch tube (SW7), and the ninth switch tube (SW9) to be turned on, and respectively controlling the first switch tube (SW1), the second switch tube (SW2), the third switch tube (SW3), the fourth switch tube (SW4), the sixth switch tube (SW6), the eighth switch tube (SW8), and the tenth switch tube (SW10) to be turned off; The flying capacitor charging process is achieved by controlling the first working state; the flying capacitor voltage balancing process is achieved by controlling the second working state, the third working state and the fourth working state, wherein the execution order of the first working state, the second working state, the third working state and the fourth working state can be adjusted arbitrarily.

8. The ladder-type switched capacitor conversion circuit according to claim 7, characterized in that: The switch tube is any one of a silicon-based MOSFET device, a silicon carbide device or a gallium nitride device.

9. The ladder-type switched capacitor conversion circuit according to claim 8, wherein: The switch control module includes: The PWM generator is used to generate pulse width modulation signals to control the on and off of each switch tube.

10. A ladder-type switched capacitor conversion method, used in the ladder-type switched capacitor conversion circuit according to any one of claims 1 to 9, characterized in that: The step-type switched capacitor conversion method includes: S1: Determine the number of steps according to the ratio of the input voltage to the output voltage, where the number of steps is a positive integer; S2: when the ratio of the input voltage to the output voltage is a non-integer, determining a voltage difference between adjacent flying capacitors according to the number of steps, the input voltage, and the output voltage; S3: controlling the charging and discharging process of the flying capacitor according to the voltage difference between the adjacent flying capacitors, so that the voltage of the last flying capacitor is equal to the output voltage or the input voltage.

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