Continuous conversion ratio step-up / step-down charge pump based on dual gyrator model

Abstract

The present invention discloses a continuous conversion ratio boost / buck charge pump based on a dual-gyrator model, which includes two serially connected single-gyrator models; the single-gyrator model is composed of N identical CELLs, and each CELL includes a capacitor C and switches S1 to S 2M+4 , the upper plate of the capacitor C is connected to V M+2 respectively through switches S1 to S IN , T M , T M‑1 ... T1, V SS ; the lower plate of the capacitor C is connected to V M+3 to V 2M+4 respectively through switches S OUT , B M , B M‑1 ... B1, V SS ; the square wave signal port is used to input a square wave signal F CLK1 , and N non-overlapping square wave signals with different phases and the same frequency are generated by a phase generation module and input into N CELLs at the same time; each CELL converts the N square wave signals into control signals for switches S1 to S 2M+4 through its respective decoder, and then controls the opening of S1 to S 2M+4 through a gate drive module. The present invention realizes continuous conversion ratio and high efficiency in both boost and buck modes, and solves the problem that a current source cannot be used as a load under a single gyrator.

Description

Technical Field

[0001] The invention relates to the field of electronic technology, and in particular to a continuous conversion ratio step-up / step-down charge pump based on a dual gyrator model. Background Art

[0002] Charge Pump is also called Switched-Capacitor DC-DC Converter. DC-DC converters are generally divided into three categories: LDO (Low Dropout Regulator, LDO), switched inductor DC-DC converter and switched capacitor DC-DC converter. Among them, switched capacitor DC-DC converter is also called charge pump. Among LDO, switched inductor DC-DC converter and charge pump, charge pump is more suitable for full integration because it only uses capacitors that are easy to design in the chip, and can achieve good efficiency through multiple voltage conversion ratios. Therefore, charge pump has become a very promising next-generation SoC power chip.

[0003] Designing a fully integrated charge pump is of great significance for small, low-power systems. However, traditional charge pumps only provide one conversion ratio, and if the output voltage deviates from this conversion ratio, the conversion efficiency will be greatly reduced, thus limiting their use in systems with varying input or output voltages. Adding more conversion ratios to traditional charge pumps can help provide greater design flexibility, but this increases the complexity of implementation and often leads to increased losses and reduced efficiency.

[0004] In order to improve the overall efficiency within a larger input and output voltage range, the system needs to provide a more continuous conversion ratio, which means that a new reconfigurable charge pump structure needs to be designed. SAR (Successive-Approximation), RSC (Recursive Switched-Capacitor), NSC (Negator Switched-Capacitor), ASSP (Asymmetrical Shunt Switched-Capacitor) type charge pumps can only achieve buck mode. In order to increase the application scenario range of reconfigurable charge pumps, AVFI (Algorithmic Voltage-Feed-In) type reconfigurable charge pumps can be used in both buck and boost modes, generating any rational number conversion ratio with optimal conduction loss, while reducing parasitic losses; ASP (Algebraic Series-Parallel) type reconfigurable charge pumps can also be used in buck and boost modes.

[0005] However, such converters do have disadvantages. First, to maintain high efficiency over a wide voltage range, multiple topologies are usually required, each of which adds additional transistors that typically create additional series resistance in the other topologies. In addition, the control overhead required to switch between different topologies increases rapidly as the number of topologies increases, resulting in worse efficiency.

[0006] In order to achieve a more continuous conversion ratio and maintain high efficiency, a single-topology continuously scalable conversion ratio charge pump is proposed. The converter adopts advanced scalable parasitic charge redistribution technology (SPCR), that is, redistributing parasitic charges through multi-phase control, thereby greatly reducing parasitic bottom plate losses and charge sharing losses. The converter derives a single-capacitor topology similar to a gyrator, achieving a continuously scalable high-efficiency conversion ratio, but it can only be applied to Buck mode or Boost mode, not both modes at the same time, and cannot use a current source as a load. Summary of the invention

[0007] The purpose of the present invention is to provide a continuous conversion ratio step-up / step-down charge pump based on a dual-gyrator model, which is used to solve the problem that the traditional single-gyrator model circuit can only be applied to the step-up or step-down mode and cannot use the current source as a load.

[0008] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0009] A continuous conversion ratio step-up / step-down charge pump based on a dual-gyrator model, comprising two single-gyrator models connected in series;

[0010] The single gyrator model is composed of N identical cells, each of which includes a capacitor C and 2M+4 switches S1~S 2M+4 , M is a positive integer; the upper plate of capacitor C is connected to switch S through switch S1 M+2 Connect to V IN , T M , T M-1 ...T1, V SS ; The lower plate of capacitor C is connected through switch S M+3 To switch S 2M+4 Connect to V OUT , B M , B M-1 ...B1, V SS ; Among them, T1~T M and B1~B M Indicates the voltage connection terminal, V INis the input voltage, V OUT is the output voltage, V SS is the ground terminal;

[0011] Each cell's V IN , V OUT , V SS , T1~T M and B1~B M Connect to the V of other N-1 cells IN , V OUT , V SS , T1~T M and B1~B M ;

[0012] The square wave signal port is used to input a square wave signal F with a duty cycle less than 1 / N. CLK1 , F CLK1 The phase generation module generates N non-overlapping square wave signals with different phases and the same frequency, and simultaneously inputs them into N cells. Each cell converts the N non-overlapping square wave signals with different phases and the same frequency into switches S1 to S2 through its own decoder. 2M+4 The control signal is then used to control S1~S 2M+4 The opening of

[0013] In the two-series single gyrator model, the V OUT Connect the V of the second gyrator IN , and connect a capacitor C1 to ground in parallel, the V OUT is the output voltage; V for the two single gyrator models SS The square wave signal ports of the two single gyrator models are respectively used to receive square wave signals with different frequencies and the same duty cycle.

[0014] Furthermore, the decoder of each cell CELL is different, so that the S1~S 2M+4 The switching sequence is different.

[0015] Furthermore, the voltage change sequence of the upper and lower plates of the capacitor C of a single cell CELL in one cycle is shown in Table 1, where N=4M+4; using the decoder and gate drive module of each cell, the N cells are in different phases at the same time, so the upper and lower plates of the capacitors in the N cells are connected to correspond to N different phases:

[0016] Table 1 The sequence of changes in the capacitor plate voltage in a single gyrator model within one cycle

[0017]

[0018] Furthermore, the T M and B M The voltage is generated by parasitic charge redistribution technology: when the plates of two different capacitors are connected, the parasitic capacitance of the plates will charge and discharge; the parasitic capacitor that needs to be discharged will transfer the charge to the parasitic capacitor that needs to be charged, so that the output voltage is the middle value before the two plates are connected; according to this method, the capacitors of multiple cells are used to cooperate, so as to transition the voltage and generate multiple voltage rails with the same spacing; among them, T1~T M and B1~B M This is the new voltage rail generated by parasitic charge redistribution technology.

[0019] Furthermore, the T1~T M V IN To V SS Voltage, B1~B M V OUT To V SS voltage.

[0020] Compared with the prior art, the present invention has the following technical features:

[0021] The present invention designs a continuous conversion ratio step-up / step-down charge pump based on a dual gyrator model, which achieves continuous conversion ratio and high efficiency in both step-up and step-down, and can use a current source as a load. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the circuit diagram of the single gyrator model;

[0023] Figure 2 This is the circuit diagram of the double gyrator model;

[0024] Figure 3 It is the principle schematic diagram of the double gyrator model;

[0025] Figure 4 (a) and (b) are the working principle diagrams of the single gyrator model in buck mode and boost mode respectively;

[0026] Figure 5 Schematic diagram of the principle of parasitic charge redistribution technology;

[0027] Figure 6 The efficiency and output voltage of the single gyrator model vary with load resistance (V IN =1V);

[0028] Figure 7 The efficiency and output voltage of the single gyrator model vary with frequency (V IN=1V load resistance 7kΩ). DETAILED DESCRIPTION

[0029] In the existing schemes, charge pumps that provide continuous conversion ratios, such as RSC, NSC, ASSC, AVFI and ASP, have complex control circuits and large switching losses, which limit the efficiency peak, and the number of conversion ratios is limited. Single-topology continuous scalable conversion ratio charge pumps can achieve a more continuous conversion ratio and have high efficiency, but they can only achieve boost or buck mode, and cannot use a current source as a load. The present invention proposes a continuous conversion ratio boost / buck charge pump of a dual gyrator model, which achieves continuous conversion ratio and high efficiency in both boost and buck, and can use a current source as a load.

[0030] The present invention proposes a continuous conversion ratio step-up / step-down charge pump adopting a dual gyrator model structure; the charge pump is composed of two single gyrator models connected in series; through the design of the single gyrator model, a continuous conversion ratio and high efficiency are achieved in both step-up and step-down modes; the input and output of the two single gyrator models are connected in series to form a charge pump of the dual gyrator model, and the dual gyrator is used to solve the problem that a current source cannot be used as a load under a single gyration.

[0031] See also Figure 1 , is the circuit block diagram of the single gyrator model; the single gyrator model consists of N identical cells (CELL), each cell CELL includes a capacitor C and 2M+4 switches S1~S 2M+4 , M is a positive integer; the size of capacitor C is the main influence of output power. The larger the capacitor, the greater the output power and the larger the area occupied; the upper plate of capacitor C is connected to switch S through switch S1. M+2 Connect to V IN , T M , T M-1 ...T1, V SS ; The lower plate of capacitor C is connected through switch S M+3 To switch S 2M+4 Connect to V OUT , B M , B M-1 ...B1, V SS ; Among them, T1~T M and B1~B M Indicates the voltage connection terminal, and also indicates the voltage at that location; V IN is the input voltage, V OUT is the output voltage, V SS is the ground terminal;

[0032] The square wave signal port is used to input a square wave signal F with a duty cycle less than 1 / N. CLK1 , FCLK1 The phase generator module generates N non-overlapping square wave signals with different phases and the same frequency, and simultaneously inputs them into N cells. Each cell converts the N non-overlapping square wave signals with different phases and the same frequency into switches S1 to S2 through its own decoder. 2M+4 The control signal is then used to control S1~S 2M+4 The decoder of each cell is different, the purpose is to make each cell S1 ~ S 2M+4 The switching sequence is different;

[0033] Each cell's V IN , V OUT , V SS , T1~T M and B1~B M Connect to the V of other N-1 cells IN , V OUT , V SS , T1~T M and B1~B M .

[0034] The working process of the above single gyrator model is:

[0035] (1) The square wave signal port inputs a square wave signal F with a duty cycle less than 1 / N CLK1 , F CLK1 The phase generation module generates N non-overlapping square wave signals with different phases and the same frequency and inputs them into all cells. Each cell selects and controls S1~S through its own decoder and gate drive module. 2M+4 Opening.

[0036] (2) The voltage change sequence of the upper and lower plates of the capacitor C of a single cell CELL within one cycle is shown in Table 1, where N = 4M + 4, that is, there are N or 4M + 4 phases in one cycle; using the decoder and gate drive module of each cell, the N cells are in different phases at the same time, so the upper and lower plates of the capacitors in the N cells are connected to exactly correspond to N different phases.

[0037] Table 1 The sequence of changes in capacitor plate voltage in a single gyrator model within one cycle

[0038]

[0039] See also Figure 2 , is a circuit diagram of a dual gyrator model, i.e., a charge pump, in the present invention.

[0040] The double gyrator model is composed of two single gyrator models in series, where the V IN is the input voltage, V of the first gyrator OUT Connect the V of the second gyrator IN , and connect a capacitor C1 to ground in parallel, the V OUT is the output voltage; V for the two single gyrator models SS The square wave signal ports of the two single gyrator models are used to receive square wave signals F with different frequencies and the same duty cycle. CLK1 、F CLK2 ; T1~T of each gyrator model M and B1~B M Not with T1~T of another rotator M and B1~B M connected; the working steps of each rotator are the same as those of a single rotator.

[0041] like Figure 3 As shown in the figure, unlike the single gyrator model, the single gyrator model cannot use a current source as a load, because the output current of the single gyrator model is determined by the conductance and the input voltage. When the current source is used as the load, the input voltage is a fixed value, which makes the conductance also a fixed value. The dual gyrator model avoids this problem.

[0042] exist Figure 3 In the equation, i1′=G1u1, i2′=G2u2, therefore u2 / u1=G2 / G1=n; i1 and u1 are the input voltage and input current of the first gyrator model, i1′ and u′ are the output voltage and output current of the first gyrator model, and G1 is the conductance of the first gyrator model; i2′ and u′ are the input voltage and input current of the second gyrator model, i2 and u2 are the output voltage and output current of the second gyrator model, and G2 is the conductance of the second gyrator.

[0043] From the working principle of the traditional gyrator, it can be known that the conductance G of each gyrator is mainly determined by the capacitance of the single unit of the gyrator and the operating frequency; the larger the capacitance of the single unit of the gyrator, the larger the conductance G, and the larger the operating frequency, the larger G. Since the capacitance of each unit is equal, the ratio of the output voltage to the input voltage can be adjusted by changing the operating frequency of the two single gyrator models.

[0044] Figure 3It can be seen that the conversion ratio n is determined by the ratio of the two conductances G2 and G1. However, the traditional single gyrator model can only be applied to buck or boost situations, and in the double gyrator model, it can be seen that the voltage relationship between u1, u2 and u′ is uncertain. Therefore, the present invention proposes a new single gyrator model to simultaneously satisfy the switching of the buck and boost states. The working principle is as follows Figure 4 shown.

[0045] Figure 4 Medium T M and B M The voltage is generated by parasitic charge redistribution technology, the principle is as follows Figure 5 As shown. When the plates of two different capacitors are connected, the parasitic capacitance of the plates will charge and discharge. The parasitic capacitor that needs to be discharged will transfer the charge to the parasitic capacitor that needs to be charged, so that the output voltage is the middle value before the two plates are connected. Using this method, multiple capacitors can be used to coordinate to transition the voltage and generate multiple voltage rails with the same spacing; among them, T1~T M and B1~B M This is the new voltage rail generated by parasitic charge redistribution technology.

[0046] Figure 4 In the buck mode (a), q can be calculated IN =CV OUT +ΔV T ,q OUT =CV IN +ΔV B ; where q IN V IN The charge input to the single gyrator model, q OUT Output to V for single gyrator model OUT The charge number, C is the capacitance in the single gyrator model; due to the parasitic charge redistribution technology, V IN , T M ~T1, V SS The difference between adjacent ports is equal, so the voltage ΔV T T M To V IN The difference between the voltage ΔV B V OUT To B M When M approaches infinity, ΔV T and ΔV B approaches 0, so q IN ≈CV OUT ,q OUT ≈CV IN The input and output are close to a gyrator model.

[0047] Similarly, in Figure 4 In the boost mode (b), q can be calculated IN =CV OUT +ΔV T ,q OUT =CV IN +ΔV B . When M approaches infinity, q IN ≈CV OUT ,q OUT ≈CV IN ; The input and output are also close to a gyrator model.

[0048] Not only that, Figure 4 The voltages of the two plates in the buck and boost modes are shown in Table 2. It can be seen that the change order of the upper plate and the lower plate in the buck and boost modes in the same cycle is the same. Therefore, no matter whether the ratio of the output voltage to the input voltage of the gyrator is greater than 1 or less than 1, the same plate change order can be used. Therefore, the single gyrator model proposed in this scheme can be applied to both boost and buck modes.

[0049] Table 2 The sequence of changes in capacitor plate voltage in a single gyrator model within one cycle

[0050]

[0051]

[0052] The present invention adjusts T1~T M V IN To V SS Voltage, B1~B M V OUT To V SS voltage, redesign the logic to get rid of V IN and V OUT The relationship of which is larger and which is smaller is fixed, so that a continuous conversion ratio is achieved in both boosting and bucking. The present invention reduces the loss of parasitic capacitance to almost zero through parasitic charge redistribution technology, so it has the characteristic of high efficiency.

[0053] Related experiments:

[0054] like Figure 6 As shown, when the load resistance of the charge pump of the present invention changes, the VCR of the charge pump is kept at a high efficiency of more than 80% when the load resistance changes, and the VCR of the charge pump is kept at a high efficiency of more than 85% when the load resistance changes. Figure 7 It can be seen that when the frequency changes, the VCR also changes accordingly, and the efficiency remains above 85% from the boost mode to the buck mode.

[0055] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A continuous conversion ratio step-up / step-down charge pump based on a dual gyrator model, characterized in that: It includes two single gyrator models connected in series; The single gyrator model is composed of N identical cells, each of which includes a capacitor C and 2M+4 switches S1~S 2M+4 , M is a positive integer; the upper plate of capacitor C is connected to switch S through switch S1 M+2 Connect to V IN , T M , T M-1 ...T1, V SS ; The lower plate of capacitor C is connected through switch S M+3 To switch S 2M+4 Connect to V OUT , B M , B M-1 ...B1, V SS ; Among them, T1~T M and B1~B M Indicates the voltage connection terminal, V IN is the input voltage, V OUT is the output voltage, V SS is the ground terminal; Each cell's V IN , V OUT , V SS , T1~T M and B1~B M Connect to the V of other N-1 cells IN , V OUT , V SS , T1~T M and B1~B M ; The square wave signal port is used to input a square wave signal F with a duty cycle less than 1 / N. CLK1 , F CLK1 The phase generation module generates N non-overlapping square wave signals with different phases and the same frequency, and simultaneously inputs them into N cells. Each cell converts the N non-overlapping square wave signals with different phases and the same frequency into switches S1 to S2 through its own decoder. 2M+4 The control signal is then used to control S1~S 2M+4 The opening of In the two-series single gyrator model, the V OUT Connect the V of the second gyrator IN , and connect a capacitor C1 to ground in parallel, the V OUT is the output voltage; V for the two single gyrator models SS The square wave signal ports of the two single gyrator models are respectively used to receive square wave signals with different frequencies and the same duty cycle.

2. The continuous conversion ratio step-up / step-down charge pump based on the dual gyrator model according to claim 1, characterized in that: The decoder of each cell is different, so that each cell is S1~S 2M+4 The switching sequence is different.

3. The continuous conversion ratio step-up / step-down charge pump based on the dual gyrator model according to claim 1, characterized in that: The voltage change sequence of the upper and lower plates of the capacitor C of a single cell CELL in one cycle is shown in Table 1, where N = 4M + 4; using the decoder and gate drive module of each cell to make N cells in different phases at the same time, the upper and lower plates of the capacitors in the N cells are connected to correspond to N different phases: Table 1 The sequence of changes in capacitor plate voltage in a single gyrator model within one cycle 。 4. The continuous conversion ratio step-up / step-down charge pump based on the dual gyrator model according to claim 1, characterized in that: The T M and B M The voltage is generated by parasitic charge redistribution technology: when the plates of two different capacitors are connected, the parasitic capacitance of the plates will charge and discharge; the parasitic capacitor that needs to be discharged will transfer the charge to the parasitic capacitor that needs to be charged, so that the output voltage is the middle value before the two plates are connected; according to this method, the capacitors of multiple cells are used to cooperate, so as to transition the voltage and generate multiple voltage rails with the same spacing; among them, T1~T M and B1~B M This is the new voltage rail generated by parasitic charge redistribution technology.

5. The continuous conversion ratio step-up / step-down charge pump based on the dual gyrator model according to claim 1, characterized in that: The T1~T M V IN To V SS Voltage, B1~B M V OUT To V SS voltage.

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