Switched capacitor type converter chip, power supply method and power supply system

Abstract

The invention discloses a switched capacitor type converter chip, a power supply method and a power supply system. The chip comprises a plurality of subunits, and each subunit works at different phases separately; each subunit comprises a flying capacitor, a fixed value type first switched capacitor converter and a second switched capacitor converter with a continuous variable conversion ratio; the first part of the flying capacitor is fixed for the second switched capacitor converter to work, and the second part of the flying capacitor is fixed for the first switched capacitor converter or the second switched capacitor converter to work; the chip is used for being connected with an energy storage capacitor and supplying power to a load. According to the invention, high-efficiency conversion of the whole energy storage capacitor discharge process can be realized, and the energy extraction efficiency is improved; through the step-up and step-down process, the voltage change range on the energy storage capacitor is expanded, and the extractable energy is improved. The invention can be widely applied to the technical field of integrated circuits.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a switched capacitor converter chip, a power supply method, and a power supply system. Background Art

[0002] With the continuous development of process and manufacturing technology, the size of IoT devices continues to shrink to the millimeter scale. Although the power consumption of IoT systems in typical working mode has been reduced to microwatts, the burst high current load power during wireless data transmission can reach milliwatts and last for tens of milliseconds. Although small solid-state batteries with high energy density can provide energy for IoT systems to operate for more than a day in typical working mode. However, due to the size restrictions of millimeter-scale IoT systems, small solid-state batteries often have high internal resistance, which will bring unacceptable voltage drop and power loss when driving high current loads. Therefore, small solid-state batteries cannot directly power the burst high current loads of IoT systems, which puts forward requirements for the ability of power management chips to support burst high current loads.

[0003] In the related art, an energy storage capacitor is connected in parallel with a battery, and then the energy is transferred to the load through a fully integrated switched capacitor power converter. In this solution, most of the energy cannot be extracted, resulting in low energy extraction efficiency, and only about 2% of the energy can be utilized. Another solution combines the energy storage capacitor with the power converter. In the typical working mode, multiple energy storage capacitors work as flying capacitors in the switched capacitor DC power converter and store energy. When a sudden high current load occurs, the connection between the energy storage capacitors is reconfigured by controlling the on-chip switches to maintain sufficient output voltage and continuously extract energy from the capacitors. However, this solution requires a large number of energy storage capacitors, and due to volume and cost limitations, this solution can only be implemented using on-chip capacitors. Summary of the invention

[0004] The purpose of the present invention is to solve one of the technical problems existing in the prior art to at least a certain extent.

[0005] Therefore, an object of the present invention is to provide a highly efficient switched capacitor converter chip, a power supply method, and a power supply system.

[0006] In order to achieve the above technical objectives, the technical solutions adopted by the embodiments of the present invention include the following aspects:

[0007] On the one hand, an embodiment of the present invention provides a switched capacitor converter chip, which includes: a plurality of subunits, each of which operates separately in different phases; each of the subunits includes: a flying capacitor, a first switched capacitor converter of a fixed value type, and a second switched capacitor converter with a continuously variable conversion ratio; the first part of the flying capacitor is fixed to work for the second switched capacitor converter, and the second part of the flying capacitor works for the first switched capacitor converter or the second switched capacitor converter; the chip is used to be connected to a storage capacitor to supply power to the load. The present application can achieve high-efficiency conversion of the entire energy storage capacitor discharge process and improve energy extraction efficiency; through the step-up and step-down process, the voltage variation range on the energy storage capacitor is expanded to increase the extractable energy.

[0008] In addition, the switched capacitor converter chip according to the above embodiment of the present invention may also have the following additional technical features:

[0009] Furthermore, in the switched capacitor converter chip of the embodiment of the present invention, the second part of the flying capacitor works for the first switched capacitor converter or the second switched capacitor converter, comprising:

[0010] a second portion of the flying capacitor operates for the second switched capacitor converter in a normal mode;

[0011] The second part of the flying capacitor works for the first switched capacitor converter and the second switched capacitor converter in the energy storage mode, and under a sudden high current load, until the voltage of the energy storage capacitor is less than the voltage of the battery, the second part of the flying capacitor works for the second switched capacitor converter.

[0012] Furthermore, in one embodiment of the present invention, the battery is connected to the chip via a current limiter, and the battery is used to supply power to the load.

[0013] Furthermore, in one embodiment of the present invention, the chip also includes: the voltage of the energy storage capacitor is greater than or equal to the voltage of the battery, and the second part of the flying capacitor is used to work for the first switched capacitor converter and the second switched capacitor converter, so that the voltage output by the energy storage capacitor is stepped down by the first switched capacitor converter and then converted by the second switched capacitor converter.

[0014] Furthermore, in one embodiment of the present invention, the chip further includes a mode selection module, and the mode selection module includes:

[0015] Comparator, switch control signal generator, analog-to-digital converter and decoder;

[0016] The comparator is used to compare the voltage of the energy storage capacitor and the voltage of the battery to generate a first enable signal; the first enable signal is used to indicate whether the first switched capacitor converter is working;

[0017] The analog-to-digital converter and the decoder are used to generate a second enable signal according to the relationship between the input node voltage and the output voltage of the second switched capacitor converter; the second enable signal is used to instruct the second switched capacitor converter to operate in step-up conversion or step-down conversion;

[0018] The switch control signal generator is used to receive the first enable signal and the second enable signal, and generate a switch control signal to the sub-unit.

[0019] Furthermore, in one embodiment of the present invention, the chip further includes a frequency control loop, and the frequency control loop includes:

[0020] Amplifiers, voltage-controlled oscillators, flip-flops, clock generators;

[0021] The amplifier is used to amplify the difference between the output voltage and the reference voltage to generate a first voltage;

[0022] The voltage-controlled oscillator is used to output a clock signal with frequency information according to the first voltage; the switch control signal generator is used to receive the clock signal and determine the switching frequency of the second switched capacitor converter;

[0023] The trigger and the clock generator are used to receive the clock signal, generate inverted and non-overlapping signals, and transmit them to the odd-numbered sub-units and the even-numbered sub-units.

[0024] Furthermore, in one embodiment of the present invention, the flying capacitor includes a high-low stacked metal-semiconductor-metal capacitor, a metal-oxide-metal capacitor and a metal-oxide-semiconductor field effect transistor capacitor.

[0025] On the other hand, an embodiment of the present invention proposes a power supply method based on a switched capacitor converter chip, wherein power is supplied by the switched capacitor converter chip, and the method includes:

[0026] adjusting the first portion of the flying capacitor to operate the second switched capacitor converter;

[0027] The second portion of the flying capacitor is adjusted to operate the first switched capacitor converter or the second switched capacitor converter.

[0028] Furthermore, the method of the embodiment of the present invention, wherein the second part of adjusting the flying capacitor works as the first switched capacitor converter or the second switched capacitor converter, comprises:

[0029] If the voltage of the energy storage capacitor is greater than or equal to the voltage of the battery, adjusting the second part of the flying capacitor to operate the first switched capacitor converter and the second switched capacitor converter;

[0030] If the voltage of the energy storage capacitor is less than the voltage of the battery, adjusting the second part of the flying capacitor to operate as the second switched capacitor converter;

[0031] If the voltage of the energy storage capacitor is less than the output voltage, the second switched capacitor converter is adjusted to operate in a boost mode. On the other hand, an embodiment of the present invention provides a power supply system, including the above-mentioned switched capacitor converter chip.

[0032] The chip provided by the embodiment of the present invention includes: a plurality of subunits, each of which works separately in different phases; each of the subunits includes: a flying capacitor, a first switching capacitor converter of a fixed value type, and a second switching capacitor converter with a continuously variable conversion ratio; the first part of the flying capacitor is fixed to work for the second switching capacitor converter, and the second part of the flying capacitor works for the first switching capacitor converter or the second switching capacitor converter; the chip is used to be connected to a piece of energy storage capacitor to supply power to the load. The present application can achieve high-efficiency conversion of the entire energy storage capacitor discharge process and improve energy extraction efficiency; through the step-up and step-down process, the voltage variation range on the energy storage capacitor is expanded to increase the extractable energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the embodiments of the present invention or the drawings of related technical solutions in the prior art are introduced below. It should be understood that the drawings introduced below are only for the convenience of clearly describing some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 A schematic structural diagram of an embodiment of a switched capacitor converter chip provided by the present invention;

[0035] Figure 2 A schematic diagram of a working curve of an embodiment of a switched capacitor converter chip provided by the present invention;

[0036] Figure 3 A schematic diagram comparing the working process of the chip provided by the present invention in different working modes;

[0037] Figure 4 A schematic diagram of the working principle of an embodiment of a switched capacitor converter provided by the present invention;

[0038] Figure 5 A schematic diagram of the phase connection state of the switched capacitor converter provided by the present invention. DETAILED DESCRIPTION

[0039] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limitations of the present invention. For the step numbers in the following embodiments, they are only provided for the convenience of explanation, and the order between the steps is not limited in any way, and the execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0040] With the continuous development of process and manufacturing technology, the size of IoT devices continues to shrink to the millimeter scale. Although the power consumption of IoT systems in typical working modes (such as standby, sampling and signal processing) has been reduced to microwatts, the burst high current load power during wireless data transmission can reach milliwatts and last for tens of milliseconds. Although small solid-state batteries with high energy density can provide energy for IoT systems to work for more than a day in typical working modes. However, due to the size restrictions of millimeter-scale IoT systems, small solid-state batteries often have high internal resistance (thousands of ohms), which will bring unacceptable voltage drop and power loss when driving high current loads. Therefore, small solid-state batteries cannot directly power the burst high current loads of IoT systems, which puts forward requirements for the ability of power management chips to support burst high current loads.

[0041] In order to support sudden high current loads, the traditional method is to connect a storage capacitor in parallel with the battery, and then transfer the energy to the load through a fully integrated switched capacitor power converter. When there is a sudden high current load, the energy storage capacitor is relied on to provide a large instantaneous current and maintain the battery voltage. Although the energy storage capacitor can store a lot of energy after charging to the battery voltage, this method requires that there should not be a large voltage drop on the energy storage capacitor, thereby limiting the extractable energy (proportional to the square of the voltage drop on the capacitor). Most of the energy cannot be extracted, resulting in low energy extraction efficiency, and only about 2% of the energy can be used. If you want to increase the wireless transmission distance (power consumption will increase when there is a sudden high current load) or extend the single-round wireless transmission time, you can only increase the capacitance of the energy storage capacitor, which will lead to a significant increase in volume and cost.

[0042] Another method is to combine energy storage capacitors with power converters. In typical operating modes, multiple energy storage capacitors work as flying capacitors in a switched capacitor DC power converter and store energy. When a high current load occurs suddenly, the connection between the energy storage capacitors is reconfigured by controlling the on-chip switches to maintain a sufficient output voltage and continuously extract energy from the capacitors. This method can extract most of the energy stored in the capacitor to the load and has a high energy extraction efficiency. However, due to the need for a large number of energy storage capacitors, this solution can only be implemented using on-chip capacitors due to volume and cost constraints, which limits the total energy that can be stored in the energy storage capacitors, thereby limiting the wireless transmission distance of the IoT system and the duration of a single round of wireless transmission.

[0043] Although the combination of on-chip energy storage capacitors and switched capacitor DC power converters can achieve higher energy extraction efficiency, the low capacitance density of on-chip capacitors limits the available energy under existing processes. Assuming that one round of wireless transmission in an IoT system consumes 10 milliwatts of power and lasts for 2 milliseconds, a total of 20 microjoules of energy is consumed, requiring about 3.5 microfarads of on-chip capacitance (assuming that the solution can achieve 70% energy extraction efficiency). Assuming that all on-chip energy storage capacitors are made of metal-insulator-metal (MIM) capacitors with a capacitance density of about 2 nanofarads per square millimeter, an area of ​​about 1750 square millimeters is required, which will bring unacceptable costs.

[0044] The solution of using off-chip capacitors as energy storage capacitors can often provide sufficient energy, but due to the strict volume and weight restrictions of millimeter-level IoT systems, there can usually only be one energy storage capacitor, lacking the flexibility to reconfigure the capacitor connection to fully extract energy. In addition, since traditional switched capacitor DC power converters can only achieve a fixed voltage conversion ratio, resulting in a very narrow input voltage range, in order to ensure the voltage stability at the load end, the energy storage capacitor is used as the input end of the power converter, and its voltage variation range is limited to a very small range. Therefore, this solution often has a low energy extraction efficiency, that is, most of the energy stored in the capacitor cannot be used, thereby limiting the performance of wireless transmission.

[0045] A reconfigurable switched capacitor power converter with multiple voltage conversion ratios can extend the input voltage range and thus improve the voltage drop of the energy storage capacitor. However, this switched capacitor power converter can only achieve a higher power conversion efficiency under a few discrete and discontinuous specific voltage conversion ratios, while the discharge of the energy storage capacitor is a continuous voltage reduction process. Therefore, using this power converter to extract energy from the energy storage capacitor can only obtain a lower average power conversion efficiency (less than 50%). Even if the energy that can be extracted is increased, the energy actually delivered to the load is still limited.

[0046] In response to the above problems, the present invention proposes a fully integrated wide input range switched capacitor DC power converter chip with a continuously variable voltage conversion ratio to achieve high conversion efficiency during the entire energy storage capacitor discharge process and improve the energy extraction efficiency of a single off-chip energy storage capacitor. In addition, a high-voltage energy storage solution is proposed to charge a single off-chip energy storage capacitor to a higher voltage to store more energy in the same volume. With the help of the boost-buck conversion function of the power converter chip proposed in the present invention, the voltage variation range on the energy storage capacitor can be further expanded, achieving higher energy extraction efficiency and extractable energy in a compact volume.

[0047] A switched capacitor converter chip and a power supply method according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings. First, a switched capacitor converter chip according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0048] Figure 1 1 is a schematic diagram of the structure of a switched capacitor converter chip according to an embodiment of the present invention, the chip comprising: a plurality of sub-units, each of the sub-units separately working in a different phase;

[0049] Each of the subunits comprises: a flying capacitor, a first switched capacitor converter of a fixed value type, and a second switched capacitor converter with a continuously variable conversion ratio;

[0050] The first part of the flying capacitor is fixed to work for the second switched capacitor converter, and the second part of the flying capacitor is fixed to work for the first switched capacitor converter or the second switched capacitor converter;

[0051] The chip is used to be connected to a piece of energy storage capacitor to supply power to a load.

[0052] Exemplarily, the first switched capacitor converter in the present application can be a 2:1 switched capacitor converter. Due to the relationship curve between the withstand voltage capability and capacitance of the energy storage capacitor, raising the energy storage voltage too high will not be worth the loss, and the target high voltage domain in the present invention is only twice the battery voltage, and the use of 2:1SC can meet the requirements of boost and buck operations; and the 2:1SC structure is simple and easy to implement. In some scenarios, technicians in this field can set the specific type of the first switched capacitor converter according to needs. In some embodiments, if replaced with other types of SC: the energy storage capacitor can be charged to a higher voltage, or the energy storage capacitor can be charged to a specified voltage with a configurable conversion ratio; the number of flying capacitors is increased, making the allocation of flying capacitors in a single subunit more complicated (for example: it is necessary to allocate 3 flying capacitors to work independently, and when necessary, the 3 capacitors need to be connected in parallel). It should be noted that replacing 2:1SC may greatly increase the complexity. Because 2:1SC is simple enough, only one flying capacitor and two-phase operation are needed to complete the boost or buck.

[0053] In some embodiments, the chip in the present application may include 13 sub-units. It is understandable that the principle of the switched capacitor converter with a continuously variable conversion ratio in the present application can be simply summarized as follows: a number of sub-units (here 13) work in staggered phases to generate some intermediate voltage rails, so that the ΔV is reduced each time the flying capacitor transfers charge (charging or discharging), thereby reducing the hard charging loss of the capacitor charging and discharging, so that the converter still maintains a high conversion efficiency at a non-optimal conversion ratio, and achieves a wide continuously variable conversion ratio. The more sub-units there are, the denser the intermediate voltage rails generated, the smaller the ΔV can be, and the higher the efficiency, but under the same chip area, the capacitance of each flying capacitor will be smaller, the ability to drive the load will deteriorate, and a higher operating frequency is required under the same load, resulting in an increase in frequency-related losses.

[0054] Optionally, in the switched capacitor converter chip in the embodiment of the present invention, the second part of the flying capacitor works for the first switched capacitor converter or the second switched capacitor converter, comprising:

[0055] a second portion of the flying capacitor operates for the second switched capacitor converter in a normal mode;

[0056] The second part of the flying capacitor works for the first switched capacitor converter and the second switched capacitor converter in the energy storage mode, and under a sudden high current load, until the voltage of the energy storage capacitor is less than the voltage of the battery, the second part of the flying capacitor works for the second switched capacitor converter.

[0057] Optionally, in the switched capacitor converter chip in the embodiment of the present invention, the battery is connected to the chip via a current limiter, and the battery is used to supply power to the load.

[0058] Optionally, the switched capacitor converter chip in the embodiment of the present invention further comprises: the voltage of the energy storage capacitor is greater than or equal to the voltage of the battery, and the second part of the flying capacitor is used to work for the first switched capacitor converter and the second switched capacitor converter, so that the voltage output by the energy storage capacitor is stepped down by the first switched capacitor converter and then converted by the second switched capacitor converter.

[0059] Optionally, the switched capacitor converter chip in the embodiment of the present invention further includes a mode selection module, and the mode selection module includes:

[0060] Comparator, switch control signal generator, analog-to-digital converter and decoder;

[0061] The comparator is used to compare the voltage of the energy storage capacitor and the voltage of the battery to generate a first enable signal; the first enable signal is used to indicate whether the first switched capacitor converter is working;

[0062] The analog-to-digital converter and the decoder are used to generate a second enable signal according to the relationship between the input node voltage and the output voltage of the second switched capacitor converter; the second enable signal is used to instruct the second switched capacitor converter to operate in step-up conversion or step-down conversion;

[0063] The switch control signal generator is used to receive the first enable signal and the second enable signal, and generate a switch control signal to the sub-unit.

[0064] Optionally, the switched capacitor converter chip in the embodiment of the present invention further includes a frequency control loop, and the frequency control loop includes:

[0065] Amplifiers, voltage-controlled oscillators, flip-flops, clock generators;

[0066] The amplifier is used to amplify the difference between the output voltage and the reference voltage to generate a first voltage;

[0067] The voltage-controlled oscillator is used to output a clock signal with frequency information according to the first voltage; the switch control signal generator is used to receive the clock signal and determine the switching frequency of the second switched capacitor converter;

[0068] The trigger and the clock generator are used to receive the clock signal, generate inverted and non-overlapping signals, and transmit them to the odd-numbered sub-units and the even-numbered sub-units.

[0069] Optionally, in the switched capacitor converter chip in the embodiment of the present invention, the flying capacitor includes a high-low stacked metal-semiconductor-metal capacitor, a metal-oxide-metal capacitor and a metal-oxide-semiconductor field effect transistor capacitor.

[0070] The following is a detailed description of the switched capacitor converter chip and power supply method provided by the present application using a specific embodiment:

[0071] The present application relates to the field of integrated circuits and their control, and in particular to a fully integrated switched capacitor converter chip with a wide input range and a continuously variable voltage conversion ratio, and a power management solution that supports sudden high current loads in a millimeter-level Internet of Things system.

[0072] In order to provide sufficient storage energy to cope with sudden high current loads, this invention uses a single off-chip energy storage capacitor, which charges the energy storage capacitor to a higher voltage to store more energy in the same volume. At the same time, this invention proposes a fully integrated wide input range switched capacitor DC power converter chip with a continuously variable voltage conversion ratio, which can continuously discharge the energy storage capacitor from high voltage to low voltage and maintain a high energy conversion efficiency throughout the process to obtain the highest possible energy extraction efficiency, and deliver sufficient energy to the load to cope with sudden high current loads of the IoT system.

[0073] Figure 1 The invention shows a switched capacitor DC power converter chip, which includes a 2:1 switched capacitor converter and a switched capacitor converter with a continuously variable conversion ratio (CSCR) for processing multipath power transmission in different working modes. The converter consists of 13 identical subunits, which work separately to meet the requirements of the CSCR switched capacitor converter for the working phase. The flying capacitor in each subunit is divided into two parts, one part of which is fixed to work as a CSCR switched capacitor converter, and the other part of the flying capacitor can be allocated between the 2:1 switched capacitor converter and the CSCR switched capacitor converter as required.

[0074] Figure 2 The working waveform diagram of the converter chip proposed in the present invention is shown. Figure 3The working status of the converter chip in different modes is shown. In normal mode, the battery voltage (VBAT) is stepped down by the CSCR switched capacitor converter to power the IoT system. At this time, all flying capacitors are allocated to the CSCR switched capacitor converter. Before a sudden high current load, the converter chip will enter the energy storage mode, and the 2:1 switched capacitor converter will be enabled to charge the energy storage capacitor (CSTO) to 2 times the battery voltage. A current limiter is connected in series with the battery to prevent the battery from providing a large current to prevent the battery voltage from being too low due to a large voltage drop caused by a large current load and high internal resistance. Because the traditional CSCR switched capacitor converter cannot directly handle high voltages, a 2:1 switched capacitor is required to step down the voltage once and then further converted by the CSCR switched capacitor converter. During a sudden high current load, the 2:1 switched capacitor first steps down the voltage on the energy storage capacitor (VSTO) to a low voltage, and then serves as the input of the CSCR switched capacitor to fully reduce the switch voltage stress. When VSTO drops below VBAT (battery voltage), the 2:1 switched capacitor is turned off and all flying capacitors are allocated to the CSCR switched capacitor converter. Then, when VSTO drops below the output voltage (Vout), the CSCR switched capacitor converter switches to boost mode and continues to extract the remaining energy in the energy storage capacitor and transmit it to the output to maximize the energy extraction in the energy storage capacitor until VSTO is lower than 1.1 volts, at which time the VSTO voltage is too low to reach the switch conduction in the CSCR switched capacitor converter. This ensures that the output voltage remains stable when the energy storage capacitor voltage continues to change, while achieving high energy extraction efficiency. The solution proposed by the present invention can extract 146 microjoules of energy when using a 0402 package 22 microfarad multilayer ceramic capacitor as an energy storage capacitor, corresponding to an energy extraction efficiency of 70.9%. When using a 220 microfarad tantalum capacitor as an energy storage capacitor, it can further provide about 5.68 millijoules of energy, corresponding to an energy extraction efficiency of 69.8%. Compared with an existing technology that uses a 7.5 millifarad supercapacitor as an energy storage capacitor, the energy extraction efficiency is increased by 35 times, the available energy for a single round of transmission is increased by 27 times, and the capacitance of the energy storage capacitor is reduced by 34 times.

[0075] The high-voltage energy storage solution proposed in the present invention enables the energy storage capacitor to store more energy in the same volume. In conjunction with the proposed converter chip, the available energy under sudden high loads of single-round wireless transmission is greatly increased. The fully integrated wide input range switched capacitor DC power converter chip with a continuously variable voltage conversion ratio proposed in the present invention can efficiently convert the continuously reduced energy storage capacitor voltage into a stable output voltage with a continuously changing voltage conversion ratio, thereby achieving high energy extraction efficiency in the entire discharge process. High energy extraction efficiency can be achieved while using a single off-chip energy storage capacitor, breaking the compromise between available energy and extraction efficiency in the prior art. Compared with the existing solution using off-chip energy storage capacitors, the energy extraction efficiency is increased by 35 times, the available energy of a single-round transmission is increased by 27 times, and the capacitance of the energy storage capacitor is reduced by 34 times.

[0076] The present invention proposes to use a switched capacitor converter with a continuously variable voltage conversion ratio to extract energy from the energy storage capacitor to cope with sudden high current loads; the proposed converter combines a 2:1 switched capacitor converter with a CSCR switched capacitor converter, increasing the ability to handle high voltages to cope with high voltages on the energy storage capacitor; 3) a high-voltage energy storage solution is proposed so that the energy storage capacitor can store more energy in the same volume.

[0077] The present invention proposes a switched capacitor converter structure that combines a 2:1 switched capacitor converter and a CSCR switched capacitor converter; it includes a high-voltage energy storage solution and a power management solution that uses a converter to extract energy from a single off-chip energy storage capacitor to cope with sudden high current loads.

[0078] Figure 4The schematic diagram of the switched capacitor converter proposed in the present invention is shown. The converter includes 13 identical power subunits, a frequency control loop and a mode selection module. The flying capacitor of each subunit is divided into CFLYA and CFLYB, where CFLYA always works for the CSCR converter and CFLYB can be allocated between the 2:1 converter and the CSCR converter. The flying capacitors in subunit 1 are labeled CFLYA,1 and CFLYB,1. Thanks to the solution proposed in the present invention that the 2:1 switched capacitor converter is used to handle high voltage, most of the switches in the converter can be implemented with low-voltage switches with nominal withstand voltage of the process. Only the switch SCT connecting the upper plates of the two flying capacitors needs to withstand a high voltage that may be as high as (2 times the battery voltage minus the output voltage), so it is implemented with a high-voltage switch. The switches in the CSCR converter are used to connect to the voltage rails VB1...VB6, VT4...VT6, etc. inside the converter to realize the unique working principle of the CSCR converter: gradually transferring charge with small step voltage changes to achieve high-efficiency power conversion that is almost independent of the conversion ratio. The 2:1 converter has 4 switches, SHa, SHb, SLa, SLb, and the switches in group a and group b are turned on alternately to achieve voltage conversion. The switches SCT and SCB are used to connect the upper and lower plates of the two flying capacitors, respectively, so that when needed, the two capacitors can be connected in parallel to work as flying capacitors of the CSCR. The voltage node VX is the output node of the 2:1 converter and the input node of the CSCR converter. It connects the two converters as an internal voltage node. The switches SSTOX and SBATX are used to switch the voltage connected to the VX node in different operating modes.

[0079] Because the flying capacitor of the 2:1 converter needs to switch between the ground and VX nodes, in order to minimize parasitic losses, all flying capacitors are implemented using Metal-Insulator-Metal (MIM). At the same time, in order to maximize the capacitance density of the on-chip flying capacitor, Metal-Oxide-Metal (MOM) and Metal-Oxide-Semiconductor Field Effect Transistor (MOS) are also used. Figure 4 As shown, the maximum density of flying capacitors on a chip is achieved by stacking MIM, MOM, and MOS capacitors in high and low order on the chip. The flying capacitors include metal-semiconductor-metal capacitors, metal-oxide-metal capacitors, and metal-oxide-semiconductor field effect transistor capacitors stacked in high and low order.

[0080] The mode selection module consists of a comparator, a switch control signal generator, a 3-bit analog-to-digital converter (3-bit ADC) and a decoder. The comparator compares the energy storage capacitor voltage VSTO and the battery voltage VBAT to determine whether the 2:1 converter needs to work. In the burst high current load mode, when VSTO is less than VBAT, the 2:1 converter is turned off and VSTO is directly connected to the CSCR for buck conversion. The comparator generates an enable signal EN_21 to the switch control signal generator. The 3-bit analog-to-digital converter is used to detect the magnitude relationship between the CSCR input node voltage VX and the output voltage Vout to determine whether the CSCR converter needs to perform a boost conversion or a buck conversion, generate an enable signal EN_BB (used to switch between buck / boost), and generate a two-bit mode selection signal MS<0,1> to control the working mode of the CSCR. The switch control signal generator receives these signals and generates appropriate switch control signals to the power sub-unit, which are then processed by the level shifter and gate driver in each power sub-unit to control each specific switch. Therefore, it can be known that the subunit in the present application is used to adjust the switch state according to the switch control signal, thereby adjusting the working mode of the first switched capacitor converter and the second switched capacitor converter.

[0081] The frequency control loop is used to adjust the operating frequency fSW of the converter and stabilize the output voltage. The difference between the output voltage Vout and the reference voltage Vref is amplified by an amplifier to generate a voltage as the input of the voltage-controlled oscillator. The output of the voltage-controlled oscillator is a clock signal with frequency information. This clock signal is sent to the switch control signal generator to determine the switching frequency of the CSCR converter. In addition, this clock signal is further divided into fSW / 2 by a D flip-flop, and then divided into inverted and non-overlapping clk1 and clk2 by a non-overlapping clock generator, and sent to the odd and even sub-units respectively, and then divided into clk1a, clk1b and clk2a, clk2b by the non-overlapping clock generator in the sub-unit to control the switch of the 2:1 converter. Such a clock signal can make the 2:1 converters of adjacent sub-units work in staggered phases, making the VX voltage more stable. The output voltage in this application is the voltage output to the load.

[0082] The connection status of a single subunit at different phases, and the corresponding relationship between the control signal and phase of the corresponding switch, such as Figure 5 shown. Figure 5A simplified example is shown: a schematic diagram of the connection status of all phases in one cycle of a CSCR switched capacitor converter with three internal rails, where VB1 and VB2 represent voltage rails that may be connected to the lower plate of the flying capacitor, and VT2 and VT3 represent voltage rails that may be connected to the upper plate of the flying capacitor. Adjusting the number of voltage rails of the upper and lower plates can adjust the ΔV of the upper and lower plates respectively. When the ΔV of the upper and lower plates are almost equal, the efficiency is highest. For example, when Vout≈1 / 3Vx, the voltage between Vx and Vout is divided by two rails, and the voltage between Vout and ground is divided by one rail. At this time, the efficiency is close to optimal. Keeping the total number of rails of the upper and lower plates equal can make the number of phases in a cycle equal to the number of sub-units required to make up the CSCR converter. For example Figure 5 The CSCR converter shown in FIG. 1 can be switched between 2 up and 1 down and 1 up and 2 down to adapt to different voltage conversion ratios (the ratio of Vout to Vx).

[0083] It should be noted that Figure 5 It only shows the connection status of the flying capacitor and does not accurately present the magnitude relationship of the rail voltage.

[0084] like Figure 5As shown, a complete cycle can be divided into odd phases and even phases. At the same time, there are only 7 subunits and corresponding flying capacitors. For example, in the odd phase, the flying capacitor C1 is in the Φ13 phase (the upper plate is connected to VT2, and the lower plate is connected to GND), and the flying capacitor C5 in the Φ5 phase is connected through the middle track VT2, forming a discharge path from ground to Vout. Similarly, in the odd phase, C3 and C6 form a discharge path from Vx to Vout, the flying capacitors C2 and C4 also form a discharge path, and the flying capacitor C7 alone also forms a discharge path, thereby transferring charge to the output end. When the phase switches, all flying capacitors are switched to the next phase, the flying capacitor C1 switches to the Φ14 phase, the flying capacitor C2 switches to the Φ12 phase, and so on. At this time, all 7 flying capacitors enter the even phase. Please note that at this time, the flying capacitor C1 still maintains the upper plate connected to VT2 and the lower plate connected to GND, while the connection states of the flying capacitors C5 and C6 have changed. The flying capacitor C1 and C6 form a discharge path again. According to the charge deduction in the flying capacitor in the previous phase, the VT2 voltage track will drop to a certain extent. When the phase is switched again, the flying capacitor C1 will enter the Φ1 phase, and the flying capacitor C2 will be two phases slower than C1 and enter the Φ13 phase, and so on. It can be found that for a single flying capacitor, its connection state switches in sequence between Φ1 and Φ14, and for the entire converter, there are always 7 flying capacitors forming the connection mode shown in the odd phase or even phase, forming a discharge path, and continuously transferring charge to the load. The intermediate tracks such as VB1,2 and VT2,3 are the intermediate voltage nodes of the flying capacitors in series. They will stabilize during the phase switching process, but they have no load capacity. The denser the middle track is, the smaller the ΔV is, the smaller the amount of charge transferred each time the flying capacitor is transferred, and the worse the load capacity is.

[0085] In the present invention, the sum of the number of tracks of the upper and lower plates is designed to be 6, so a total of 13 sub-units are included, and each cycle has a total of 26 phases. Of course, this application does not limit the above number, and those skilled in the art can adjust it according to needs.

[0086] Secondly, a power supply method based on a switched capacitor converter chip is provided in an embodiment of the present invention. The method in the embodiment of the present invention can be applied to a terminal, a server, or software running in a terminal or a server. The terminal can be a tablet computer, a laptop computer, a desktop computer, etc., but is not limited thereto. The server can be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The method in the embodiment of the present invention is applied to the switched capacitor converter chip described above, and mainly includes the following steps:

[0087] adjusting the first portion of the flying capacitor to operate the second switched capacitor converter;

[0088] The second portion of the flying capacitor is adjusted to operate the first switched capacitor converter or the second switched capacitor converter.

[0089] Optionally, in the method in the embodiment of the present invention, the second part of adjusting the flying capacitor works as the first switched capacitor converter or the second switched capacitor converter, comprising:

[0090] If the voltage of the energy storage capacitor is greater than or equal to the voltage of the battery, adjusting the second part of the flying capacitor to operate the first switched capacitor converter and the second switched capacitor converter;

[0091] If the voltage of the energy storage capacitor is less than the voltage of the battery, adjusting the second part of the flying capacitor to operate as the second switched capacitor converter;

[0092] If the voltage of the energy storage capacitor is lower than the output voltage, the second switched capacitor converter is adjusted to operate in a boost mode.

[0093] It can be seen that the contents of the above chip embodiments are all applicable to the present method embodiments, the functions specifically implemented by the present method embodiments are the same as those of the above chip embodiments, and the beneficial effects achieved are also the same as those achieved by the above chip embodiments.

[0094] On the other hand, an embodiment of the present invention provides a power supply system, including the above-mentioned switched capacitor converter chip.

[0095] Similarly, the contents of the above chip embodiments are all applicable to the present system embodiments. The functions specifically implemented by the present system embodiments are the same as those of the above chip embodiments, and the beneficial effects achieved are also the same as those achieved by the above chip embodiments.

[0096] In some selectable embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiment presented and described in the flow chart of the present invention is provided by way of example, for the purpose of providing a more comprehensive understanding of technology. The disclosed method is not limited to the operation and logic flow presented herein. Selectable embodiments are expected, wherein the order of various operations is changed and the sub-operation of a part for which is described as a larger operation is performed independently.

[0097] In addition, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise specified, one or more of the functions and / or features can be integrated into a single physical device and / or software module, or one or more functions and / or features can be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the present invention. More specifically, in view of the properties, functions and internal relationships of the various functional modules in the device disclosed herein, the actual implementation of the module will be understood within the conventional skills of the engineer. Therefore, those skilled in the art can implement the present invention set forth in the claims without excessive experimentation using ordinary techniques. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0098] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several programs to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0099] The logic and / or steps represented in the flowchart or otherwise described herein, for example, may be considered as an ordered list of executable programs for implementing the logical functions, and may be embodied in any computer-readable medium for use by a program execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch and execute a program from a program execution system, device or apparatus), or in conjunction with such program execution systems, devices or apparatuses. For purposes of this specification, a "computer-readable medium" may be any device that can contain, store, communicate, propagate or transmit a program for use by a program execution system, device or apparatus, or in conjunction with such program execution systems, devices or apparatuses.

[0100] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0101] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable program execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0102] In the above description of this specification, the description with reference to the terms "one embodiment / example", "another embodiment / example" or "certain embodiments / examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0103] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0104] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A switched capacitor converter chip, characterized in that: The chip comprises: a plurality of sub-units, each of which operates separately in a different phase; Each of the subunits comprises: a flying capacitor, a first switched capacitor converter of a fixed value type, and a second switched capacitor converter with a continuously variable conversion ratio; The first part of the flying capacitor is fixed to work for the second switched capacitor converter, and the second part of the flying capacitor is fixed to work for the first switched capacitor converter or the second switched capacitor converter; The chip is used to be connected to a piece of energy storage capacitor to supply power to a load.

2. The switched capacitor converter chip according to claim 1, characterized in that: The second part of the flying capacitor operates for the first switched capacitor converter or the second switched capacitor converter, comprising: a second portion of the flying capacitor operates for the second switched capacitor converter in a normal mode; The second part of the flying capacitor works for the first switched capacitor converter and the second switched capacitor converter in the energy storage mode, and under a sudden high current load, until the voltage of the energy storage capacitor is less than the voltage of the battery, the second part of the flying capacitor works for the second switched capacitor converter.

3. The switched capacitor converter chip according to claim 2, characterized in that: The battery is connected to the chip via a current limiter, and the battery is used to supply power to the load.

4. The switched capacitor converter chip according to claim 2, characterized in that: The chip also includes: the voltage of the energy storage capacitor is greater than or equal to the voltage of the battery, and the second part of the flying capacitor is used to work for the first switched capacitor converter and the second switched capacitor converter, so that the voltage output by the energy storage capacitor is stepped down by the first switched capacitor converter and then converted by the second switched capacitor converter.

5. The switched capacitor converter chip according to claim 1, characterized in that: The chip further includes a mode selection module, which includes: Comparator, switch control signal generator, analog-to-digital converter and decoder; The comparator is used to compare the voltage of the energy storage capacitor and the voltage of the battery to generate a first enable signal; the first enable signal is used to indicate whether the first switched capacitor converter is working; The analog-to-digital converter and the decoder are used to generate a second enable signal according to the relationship between the input node voltage and the output voltage of the second switched capacitor converter; the second enable signal is used to instruct the second switched capacitor converter to operate in step-up conversion or step-down conversion; The switch control signal generator is used to receive the first enable signal and the second enable signal, and generate a switch control signal to the sub-unit.

6. The switched capacitor converter chip according to claim 5, characterized in that: The chip also includes a frequency control loop, and the frequency control loop includes: Amplifiers, voltage-controlled oscillators, flip-flops, clock generators; The amplifier is used to amplify the difference between the output voltage and the reference voltage to generate a first voltage; The voltage-controlled oscillator is used to output a clock signal with frequency information according to the first voltage; the switch control signal generator is used to receive the clock signal and determine the switching frequency of the second switched capacitor converter; The trigger and the clock generator are used to receive the clock signal, generate inverted and non-overlapping signals, and transmit them to the odd-numbered sub-units and the even-numbered sub-units.

7. The switched capacitor converter chip according to claim 5, characterized in that: The flying capacitors include high-low stacked metal-semiconductor-metal capacitors, metal-oxide-metal capacitors and metal-oxide-semiconductor field effect transistor capacitors.

8. A power supply method based on a switched capacitor converter chip, characterized in that: Power is supplied by a switched capacitor converter chip as claimed in any one of claims 1 to 7, the method comprising: adjusting the first portion of the flying capacitor to operate the second switched capacitor converter; The second portion of the flying capacitor is adjusted to operate the first switched capacitor converter or the second switched capacitor converter.

9. The method according to claim 8, characterized in that The second part of adjusting the flying capacitor works for the first switched capacitor converter or the second switched capacitor converter, comprising: If the voltage of the energy storage capacitor is greater than or equal to the voltage of the battery, adjusting the second part of the flying capacitor to operate the first switched capacitor converter and the second switched capacitor converter; If the voltage of the energy storage capacitor is less than the voltage of the battery, adjusting the second part of the flying capacitor to operate as the second switched capacitor converter; If the voltage of the energy storage capacitor is lower than the output voltage, the second switched capacitor converter is adjusted to operate in a boost mode.

10. A power supply system, characterized in that: The invention comprises a switched capacitor converter chip as claimed in any one of claims 1 to 7.

Images