Power supply circuits and electronic devices

Abstract

To improve conversion efficiency from a single input voltage to a plurality of different output voltages.SOLUTION: A power supply circuit that converts a single input voltage into output voltages of a plurality of levels, the power supply circuit including one or more switched capacitors that are capable of transforming the input voltage at a transformation ratio of one or more levels and apply a lower transformation ratio as the input voltage is higher, and a regulator that adjusts an intermediate voltage based on output power from the switched capacitors to the output voltage.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This application relates to power supply circuits and devices, for example, electronic circuits that convert a single DC power source into power sources having multiple different voltages. [Background technology]

[0002] Electronic devices such as personal computers (PCs) include many electronic components, each of which requires power at a different voltage. Such information devices have a power supply circuit that converts power supplied from a power source into multiple different voltage levels and outputs power having the converted voltage. The power supply circuit includes multiple circuit elements, such as a DC converter and a regulator. These circuit elements are sometimes integrated into a power management integrated circuit (PMIC).

[0003] For example, the information processing device described in Patent Document 1 has a power supply unit that supplies power to each unit based on power supplied from an internal battery or an AC adapter, and controls charging of the internal battery based on the power supplied from the AC adapter. The power supply unit includes a PMIC, and detects and controls charging voltage and charging current, and controls ON / OFF of power supply to each unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-140426 Summary of the Invention [Problem to be solved by the invention]

[0005] Some PMICs have multiple output rails capable of outputting power with different output voltages. Generally, the greater the voltage difference between input and output, the lower the voltage conversion efficiency. Furthermore, boosting tends to be more efficient than bucking. Therefore, it is difficult to improve conversion efficiency for all output voltages for a single input voltage. Furthermore, PMICs can be supplied with power discharged from a battery, not just power from a commercial power source via an AC adapter. In such cases, the input voltage can fluctuate significantly depending on the battery configuration or remaining charge. This makes optimizing conversion efficiency even more difficult. [Means for solving the problem]

[0006] The present application has been made to solve the above-mentioned problems, and provides a power supply circuit according to one embodiment, which converts a single input voltage into a plurality of output voltage stages, and which includes one or more switched capacitors capable of transforming the input voltage at one or more transformation ratios, the higher the input voltage, the lower the transformation ratio that is applied, and one or more regulators that adjust an intermediate voltage based on output power from the switched capacitors to the output voltage.

[0007] In the above power supply circuit, the one or more switched capacitors may include a first switched capacitor capable of stepping up the input voltage at a predetermined step-up ratio and a second switched capacitor capable of stepping down the input voltage at a predetermined step-down ratio, wherein the first switched capacitor steps up the input voltage when the input voltage is lower than a predetermined first reference voltage and the second switched capacitor steps down the input voltage when the input voltage is higher than a predetermined second reference voltage, and the one or more regulators may include a first regulator that adjusts a first intermediate voltage based on a first output power from the first switched capacitor to a first output voltage that is a part of the output voltage, and a second regulator that adjusts a second intermediate voltage based on a second output power from the second switched capacitor to a second output voltage that is another part of the output power.

[0008] In the above power supply circuit, the input voltage may be a discharge voltage of a battery, and the switched capacitor may set the transformation ratio based on a configuration of the battery.

[0009] The above power supply circuit may further include a step-down converter that steps down the second output power from the second switched capacitor, or a step-up converter that steps up the first output power from the first switched capacitor.

[0010] In the above power supply circuit, the one or more switched capacitors; The one or more regulators may be integrated.

[0011] An electronic device according to a second aspect of the present application includes a battery and the above power supply circuit. [Effects of the Invention]

[0012] According to the embodiments of the present application, it is possible to improve the efficiency of conversion from a single input voltage to a plurality of different output voltages. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram showing an example of the configuration of a power supply circuit according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram showing a first configuration example of a logic PMIC according to the present embodiment. [Figure 3] FIG. 10 is a block diagram showing a second configuration example of the logic PMIC according to the present embodiment. [Figure 4] FIG. 2 is an explanatory diagram showing a first operation example of the switched capacitor according to the present embodiment. [Figure 5] FIG. 10 is an explanatory diagram showing a second operation example of the switched capacitor according to the present embodiment. [Figure 6] FIG. 10 is an explanatory diagram showing a third operation example of the switched capacitor according to the present embodiment. [Figure 7] FIG. 1 is a diagram illustrating an example of the configuration of a switched capacitor. [Figure 8]FIG. 1 is a schematic block diagram illustrating an example of a hardware configuration of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, an outline of a power supply circuit 1 according to an embodiment of the present invention will be described. FIG. 1 is a block diagram showing an example of the configuration of a power supply circuit 1 according to this embodiment. The power supply circuit 1 illustrated in FIG. 1 is mainly applied to a display unit or an electronic device equipped with a display unit. The power supply circuit 1 includes an EN signal generation circuit 10, a logic PMIC 20, and a backlight PMIC 30.

[0015] The EN signal generation circuit 10 generates an enable (EN) signal from power supplied from a power supply. The EN signal is a control signal for instructing the operation of the logic PMIC 20. The EN signal has a signal voltage significantly higher than 0 V (typically 2 to 4 V, e.g., 3.3 V) and indicates that the function of the logic PMIC 20 is enabled. The EN signal generation circuit 10 includes, for example, a regulator. The regulator converts the power supply voltage VBAT into the signal voltage of the EN signal.

[0016] The power supplied from the power supply is also branched and supplied to the logic PMIC 20 and the backlight PMIC 30 . The logic PMIC (Logic Power Management Integrated Circuit) 20 is a PMIC that supplies power to the logic circuit provided in the display unit. The logic PMIC 20 receives power from a power supply and can transform the input voltage of the supplied power into a predetermined number of output voltage levels. In the example of FIG. 1, the logic PMIC 20 has one power supply terminal, one control terminal, and five output terminals. Power is supplied from the power supply to the power supply terminal. An EN signal is input to the control terminal from the EN signal generation circuit 10. The logic PMIC enables its function when the EN signal is input, and stops operation when the EN signal is not input.

[0017] The logic PMIC 20 converts one input voltage VCC into five output voltages VH01, VH02, VL01, VL02, and VL03. When the input voltage VCC is equal to the rated battery voltage (e.g., 5V), the output voltages VH01 and VH02 are set to values ​​higher than the input voltage VCC (e.g., 10-15V). The output voltages VL01, VL02, and VL03 are set to values ​​lower than the input voltage VCC (e.g., 1.2-3V). The logic PMIC 20 supplies power having individual output voltages to elements that make up the electronic device via the respective output terminals.

[0018] The logic PMIC 20 includes one or more switched capacitors and one or more regulators. The switched capacitor can transform an input voltage at one or more transformation ratios, with a lower transformation ratio being applied as the input voltage increases. The transformation ratio corresponds to the ratio of the output voltage to the input voltage. The transformation ratio is a general term for the step-up ratio and the step-down ratio. The logic PMIC 20 can transform the input voltage at a predetermined transformation ratio and can adjust the transformation ratio of the transformed voltage according to the input voltage. The regulator adjusts the voltage of the power output from the switched capacitor or the intermediate power, which is further transformed or branched power, to the output voltages VH01, VH02, VL01, VL02, and VL03 for each stage. An example configuration of the logic PMIC 20 will be described later.

[0019] A backlight PMIC (Backlight Power Management Integrated Circuit) 30 receives power from a power supply. The backlight PMIC 30 is an integrated circuit that converts the input voltage VBAT of the supplied power into an input voltage BL_PWR for the backlight and converts it into an output voltage for the backlight. In other words, the backlight PMIC 30 functions as a voltage source for the display unit. The output voltage for the backlight may be a predetermined constant value or may be variable in response to a command from a controller of the electronic device. The output voltage for the backlight may be one step, but may be higher than the input voltage. The output voltage for the backlight is, for example, 30-40 V. The backlight PMIC 30 supplies power having the converted output voltage to the backlight of the display.

[0020] Next, a description will be given of a configuration example of the logic PMIC 20 according to this embodiment. Fig. 2 is a block diagram showing a first configuration example of the logic PMIC 20 according to this embodiment. The logic PMIC 20 according to this configuration example includes switched capacitors 21 and 22, a transformer 23, a high-voltage output regulator 25, and a low-voltage output regulator 26.

[0021] The switched capacitor 21 is capable of boosting the input voltage of power supplied from a power supply at a predetermined boost ratio. When the input voltage is lower than a predetermined first reference voltage, the switched capacitor 21 boosts the input voltage and determines the boosted voltage as a first intermediate voltage VH. When the input voltage is equal to or higher than the first reference voltage, the switched capacitor 21 does not boost the input voltage but determines it as the first intermediate voltage VH. The switched capacitor 21 outputs power having the first intermediate voltage VH to the high-voltage output regulator 25 as first intermediate power.

[0022] The switched capacitor 22 can step down the input voltage of power supplied from the power source at a predetermined step-down ratio. When the input voltage is higher than a predetermined second reference voltage, the switched capacitor 22 steps down the input voltage and determines the stepped-down voltage as the first-stage second intermediate voltage. When the input voltage is equal to or lower than the second reference voltage, the switched capacitor 22 does not step down the input voltage but determines it as the first-stage second intermediate voltage. The switched capacitor 22 outputs power having the first-stage second intermediate voltage to the transformer 23 as the first-stage second intermediate power.

[0023] Transformer 23 steps down the second intermediate voltage, which is the voltage of the first-stage second intermediate power input from switched capacitor 22, at a predetermined transformation ratio. Unlike switched capacitors 21 and 22, transformer 23 has a fixed transformation ratio. Transformer 23 outputs the second-stage intermediate power, having the stepped-down voltage as second-stage intermediate voltage VL, to low-voltage output regulator 26.

[0024] The high-voltage output regulator 25 adjusts the first intermediate voltage VH of the first intermediate power input from the switched capacitor 21 to predetermined output voltages VH01 and VH02. The high-voltage output regulator 25 outputs output powers having the adjusted output voltages VH01 and VH02 to components requiring power having the respective output voltages. The high voltage output regulator 25 includes, for example, a boost converter, a buck converter, and a charge pump.

[0025] The low-voltage output regulator 26 adjusts the second intermediate voltage VL of the second intermediate power input from the transformer 23 to predetermined output voltages VL01, VL02, and VL03. The low-voltage output regulator 26 outputs output power having the adjusted output voltages VL01, VL02, and VL03 to the required components. The low-voltage output regulator 26 includes one or more step-down converters.

[0026] When a battery is used as a power source, the input voltage VBAT varies greatly depending on the number of cells and the remaining charge of the battery. A cell is the building block of a battery. When multiple cells are connected in series in a battery, the input voltage is proportional to the number of cells. Also, the higher the remaining charge, the higher the input voltage VBAT. Generally, the input voltage VBAT is highest when the battery is fully charged. On the other hand, the multiple output voltage stages can each be set to a constant value. Some output voltage stages are higher than the input voltage, but others can be lower.

[0027] Output voltages VH01 and VH02, which are likely to be higher than the input voltage VBAT, are provided from a high-voltage output regulator 25. The operating parameters of the switched capacitor 21 and the high-voltage output regulator 25 are set so that the input voltage to the high-voltage output regulator 25 is often equal to or higher than the maximum value of the output voltages VH01 and VH02, and a first intermediate voltage VH is obtained that is as small as possible from the maximum value. The operating parameters include the boost ratio and first reference power of the switched capacitor 21. In many cases, the remaining charge of a battery with a relatively small number of cells (e.g., two cells) reaches a lower limit (e.g., 10 to 20%), and the first intermediate voltage VH obtained by boosting the switched capacitor 21 can be used as a parameter setting condition.

[0028] If the input voltage is significantly lower than the output voltages VH01 and VH02, a transformer (not shown) may be connected downstream of the switched capacitor 21. The transformer boosts the power supplied from the switched capacitor 21 and supplies the boosted power to the high-voltage output regulator. In this case, the voltage of the power boosted by the switched capacitor 21 is set as the first intermediate voltage VH, and the boost rate, which is a parameter of the transformer, is further set based on the above-mentioned criteria.

[0029] The output voltages VL01, VL02, and VL03, which are likely to be lower than the input voltage VBAT, are provided by the low-voltage output regulator 26. The operating parameters of the switched capacitor 22, the transformer 23, and the low-voltage output regulator 26 are set so that the input voltage to the low-voltage output regulator 26 is often equal to or higher than the maximum value of the output voltages VL01, VL02, and VL03, and a second intermediate voltage VL is obtained that is as small as possible from the maximum value. The operating parameters include the step-down ratio of the switched capacitor 22, the second reference power, and the step-down ratio of the transformer 23. For example, when the remaining charge of a battery with a predetermined number of cells (e.g., four cells) reaches an upper limit, the second intermediate voltage VL obtained by stepping down the switched capacitor 22 can be applied as a parameter setting condition.

[0030] If the difference between the input voltage and the output voltages VL01, VL02, and VL03 is smaller, the transformer 23 may be omitted. In that case, the power output from the switched capacitor 22 is directly supplied to the low-voltage output regulator 26, and therefore, the voltage of the power supplied from the switched capacitor 22 is set as the second intermediate voltage VL, and the operating parameters of the switched capacitor 22 and the low-voltage output regulator 26 can be set based on the above-mentioned criteria.

[0031] Next, a second configuration example of the logic PMIC 20 according to this embodiment will be described. The following description will mainly focus on the differences from the first configuration example. The same reference numerals are used for the components common to the first configuration example, and the same description will be used unless otherwise specified. FIG. 3 is a block diagram showing a second configuration example of the logic PMIC 20 according to this embodiment. The logic PMIC 20 according to this configuration example includes a switched capacitor 21S, a transformer 23, a high-voltage output regulator 25, and a low-voltage output regulator 26. That is, the logic PMIC 20 according to this configuration differs in that it includes a switched capacitor 21S instead of the switched capacitors 21 and 22.

[0032] The switched capacitor 21S can switch between three states, boost, buck, and pass, depending on the input voltage VBAT. When the input voltage VBAT is lower than the first reference voltage, the switched capacitor 21S boosts the input voltage VBAT supplied from the power supply at a predetermined boost ratio, supplies the boosted voltage as an intermediate voltage VH to the high-voltage output regulator 25 as a first intermediate power, and supplies power that maintains the input voltage VBAT unchanged to the transformer 23 as a first-stage second intermediate power.

[0033] When the input voltage VBAT is equal to or greater than the first reference voltage and equal to or less than the second reference voltage, the switched capacitor 21S branches the power, which is maintained without changing the input voltage VBAT, into a first intermediate power and a first-stage second intermediate power, and supplies the first intermediate power to the high-voltage output regulator 25 and the first-stage second intermediate power to the transformer 23.

[0034] When the input voltage VBAT is higher than the second reference power, the switched capacitor 21S steps down the input voltage VBAT supplied from the power supply at a predetermined step-down ratio, supplies the power having the stepped-down voltage to the transformer 23 as the first-stage second intermediate power, and supplies the power that maintains the input voltage VBAT unchanged to the high-voltage output regulator 25 as the first intermediate power.

[0035] If the power source is a battery, the switched capacitors 21, 22, or 21S may use the battery configuration as an index value for the input voltage VBAT when determining whether conversion of the input voltage VBAT is necessary or whether to boost, buck, or pass the input voltage VBAT. A battery may include multiple cells, and these cells may be connected in series. The output voltage of the power discharged from the battery is proportional to the number of cells connected in series (sometimes referred to as the "number of cells" in this application). The switched capacitors 21, 22, or 21S may use the number of cells as configuration information for the battery. For example, the battery may notify the switched capacitors 21, 22, or 21S of configuration information indicating the number of cells in its own battery using a predetermined communication method.

[0036] Next, an example of the operation of the logic PMIC 20 according to the second configuration example will be described using the following conditions as an example: The switched capacitor 21S determines the input voltage based on the number of cells, which indicates the battery configuration. The input voltage is variable within the range of 2S to 4S. S indicates the rated voltage of one cell. 1S is typically 2.5 to 5V. The output voltages VH01 and VH02 are all higher than 2S. The maximum values ​​of the output voltages VH01 and VH02 are higher than 3S. The output voltages VL01, VL02, and VL03 are all lower than 2S. The step-up ratio and step-down ratio of the switched capacitor 21S and the step-down ratio of the transformer 23 are 1:2, 2:1, and 2:1, respectively. The first reference voltage and the second reference voltage are 2.5S and 3.5S, respectively.

[0037] 4 to 6 are explanatory diagrams each showing an example of the operation of the switched capacitor 21S. Fig. 4 shows the behavior of the switched capacitor 21S when the number of cells is two, that is, when the input voltage VBAT is 2S. In this case, the switched capacitor 21S boosts the input voltage VBAT supplied from the power supply at a boost ratio of 1:2, and supplies the high-voltage output regulator 25 with a first intermediate power having the boosted voltage as the intermediate voltage VH. Since the input voltage VBAT is lower than the second reference voltage, the switched capacitor 21S does not step down the input voltage VBAT, and passes the power supplied from the power supply to the transformer 23 as the second intermediate power of the first stage.

[0038] FIG. 5 shows the behavior of the switched capacitor 21S when the number of cells is three, that is, when the input voltage VBAT is 3S. In this case, the switched capacitor 21S does not step down the input voltage VBAT, and passes the power supplied from the power supply to the high-voltage output regulator 25 as the first intermediate power. Furthermore, the switched capacitor 21S does not step down the input voltage VBAT, but passes the power supplied from the power supply to the transformer 23 as the second intermediate power of the first stage.

[0039] FIG. 6 shows the behavior of the switched capacitor 21S when the number of cells is four, that is, when the input voltage VBAT is 4S. In this case, the switched capacitor 21S does not step down the input voltage VBAT, but passes the power supplied from the power supply to the high-voltage output regulator 25 as the first intermediate power. Furthermore, the switched capacitor 21S steps down the input voltage VBAT supplied from the power supply at a step-down ratio of 2:1, and supplies the power having the stepped-down voltage to the transformer 23 as the first-stage second intermediate power.

[0040] When the logic PMIC 20 includes the switched capacitors 21 and 22 as in the first configuration example, the same effects and advantages as when the logic PMIC 20 includes the switched capacitor 21S can be obtained. 4, the switched capacitor 21 boosts the input voltage VBAT supplied from the power supply at a boost ratio of 1:2, and supplies a first intermediate power having the boosted voltage as an intermediate voltage VH to the high-voltage output regulator 25. The switched capacitor 22 does not step down the input voltage VBAT, and passes the power supplied from the power supply to the transformer 23 as a first-stage second intermediate power.

[0041] 5, the switched capacitor 21 does not step down the input voltage VBAT, but passes the power supplied from the power supply to the high-voltage output regulator as a first intermediate power. The switched capacitor 21S does not step down the input voltage VBAT, but passes the power supplied from the power supply to the transformer 23 as a first-stage second intermediate power. In the example of FIG. 6, the switched capacitor 21S does not step down the input voltage VBAT, but passes the power supplied from the power supply to the high-voltage output regulator 25 as the first intermediate power. Since the input voltage VBAT is higher than the second reference voltage, the switched capacitor 22 steps down the input voltage VBAT supplied from the power supply at a step-down ratio of 2:1, and supplies the power having the stepped-down voltage to the transformer 23 as the second intermediate power of the first stage.

[0042] In this way, the switched capacitors 21, 22, and 21S each switch between the need for boosting and the need for stepping down, depending on the input voltage VBAT or the battery configuration. The voltage obtained by boosting the input voltage VBAT approaches the higher output voltages VH01 and VH02, or exceeds the output voltages VH01 and VH02. Since boosting in the high-voltage output regulator 25 is avoided or suppressed, it is possible to avoid or suppress a decrease in efficiency due to boosting. In this regard, the switched capacitor 21 can boost the input voltage VBAT with high efficiency (e.g., 97 to 99%), thereby improving the efficiency of the logic PMIC 20 as a whole. Furthermore, by stepping down the input voltage VBAT, it approaches the lower output voltages VL01, VL02, and VL03. This reduces the difference between the input voltage and the output voltage of the low-voltage output regulator 26, thereby suppressing a decrease in efficiency. This ultimately improves the efficiency of the logic PMIC 20 as a whole.

[0043] Next, a configuration example of the switched capacitor 22 according to this embodiment will be described. FIG. 7 is a diagram showing a configuration example of the switched capacitor 22. The switched capacitor 22 includes capacitance elements C1 and C2, switching elements SW1-SW4, and a drive circuit 22d. With this configuration, the switched capacitor 22 can step down the input voltage at a step-down ratio of 2:1. The capacitance elements C1 and C2 are, for example, capacitors. The capacitances of the capacitance elements C1 and C2 may be equal to or different from each other. The switching elements SW1-SW4 are, for example, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors).

[0044] Power is supplied from the power supply to the input terminal VA. The output terminal VB may supply stepped-down power or may supply the power from the power supply without stepping down the power. One end of the switching element SW1 is connected to the input terminal VA, and the other end of the switching element SW1 is connected to one end of the capacitive element C1 and one end of the switching element SW2. One end of the switching element SW2 is connected to the other end of the switching element SW1 and one end of the capacitance element C1, and the other end of the switching element SW2 is connected to one end of the capacitance element C2, the other end of the switching element SW3 and the output terminal VB.

[0045] One end of the switching element SW3 is connected to the other end of the capacitance element C3 and one end of the switching element SW4, and the other end of the switching element SW3 is connected to the other end of the switching element SW2, one end of the capacitance element C2 and the output terminal VB. One end of the switching element SW4 is connected to the other end of the capacitance element C1 and one end of the switching element SW3, and the other end of the switching element SW4 is connected to the potential reference point GND and the other end of the capacitance element C2.

[0046] When the switching elements SW1, SW2, SW3, and SW4 are respectively in the ON state (closed), OFF state (open), ON state (closed), and OFF state (open), the capacitance elements C1 and C2 are connected in series between the input terminal VA and the potential reference point GND. At this time, the voltage divided between the input terminal VA and the potential reference point GND is applied to the capacitance elements C1 and C2, and electric charge is accumulated. When the switching elements SW1, SW2, SW3, and SW4 are respectively in the ON state (closed), ON state (closed), OFF state (open), and ON state (closed), the capacitance elements C1 and C2 are connected in parallel between the input terminal VA and the potential reference point GND. At this time, the accumulated charge is discharged from one end of each of the capacitance elements C1 and C2.

[0047] When the input voltage is higher than the second reference voltage, the drive circuit 22d controls the states of the switching elements SW1, SW2, SW3, and SW4 so that the capacitive elements C1 and C2 are repeatedly switched between a state in which they are connected in series and a state in which they are connected in parallel at regular intervals. Therefore, power having an output voltage that is a voltage stepped down from the input voltage at a step-down ratio of 2:1 is output from the output terminal VB. When the input voltage becomes equal to or lower than the second reference voltage, the drive circuit 22d controls the states of the switching elements SW1, SW2, SW3, and SW4 so that the parallel connection of the capacitance elements C1 and C2 is fixed. Because the input terminal VA and the output terminal VB are connected and the capacitance elements C1 and C2 are sandwiched between them and the potential reference point GND, the input voltage is not stepped down and the supplied power is output.

[0048] 7 is capable of stepping down the input voltage at a step-down ratio of 2:1 by alternately switching the connection state of two capacitance elements between series and parallel by switching a switching element, but is not limited to this. The switched capacitor 22 may include M (an arbitrary predetermined integer equal to or greater than 2) capacitance elements, and may be capable of stepping down the input voltage at a step-down ratio of M:1 by alternately switching the connection state of the M capacitance elements between series and parallel.

[0049] The switched capacitor 21 is configured by inverting the input / output relationship of power compared to the switched capacitor 22 illustrated in Fig. 7, and by switching the connection state of the capacitance elements C1 and C2 when the input voltage is lower than the first reference voltage, and by fixing the connection state of the capacitance elements C1 and C2 in parallel when the input voltage is equal to or higher than the first reference voltage. Switching the connection state of the capacitance elements C1 and C2 achieves a boost ratio of 1:2. The inversion of the input / output relationship means that power supplied from a power supply is input to a terminal corresponding to the output terminal VB in Fig. 6, and power is output from a terminal corresponding to the input terminal VA, either boosted or not boosted.

[0050] The switched capacitor 21S is realized by combining switching of the input / output relationship and switching of the connection state of the capacitance element in the switched capacitor 22 illustrated in Fig. 7. This configuration makes it possible to switch between three states: boost, buck, and pass. The boost ratio for boosting is the reciprocal of the buck ratio for bucking.

[0051] In this embodiment, the switched capacitors 21, 21S, and 22 may each be configured as a single integrated circuit, or may be configured to include two or more circuits, elements, or a combination thereof. Any one of the switched capacitors 21, 21S, and 22, or any combination thereof, may itself be configured as a power supply circuit. The switched capacitors 21, 21S, and 22 themselves may be used as part or all of the power supply circuit of an electronic device to which power can be supplied. For example, the backlight PMIC 30 is not necessarily required for an electronic device that does not have a display 44 or depending on the display type.

[0052] Next, a configuration example of the electronic device according to this embodiment will be described. 8 is a schematic block diagram showing an example of the configuration of an electronic device D1 according to this embodiment. The electronic device D1 is configured as, but is not limited to, a general-purpose personal computer (PC). The electronic device D1 includes a host system 40, a video subsystem 43, a display 44, an external memory 52, an input / output I / F 56, an EC (Embedded Controller) 61, an input device 62, a power supply circuit 1, a battery 66, and an AC (Alternating Current) adapter 67.

[0053] The host system 40 is a computer system that forms the core of the electronic device D1. The host system 40 includes a processor, a main memory, and a chipset. The processor executes various processes instructed by instructions written in a program, and includes, for example, one or more central processing units (CPUs). The main memory is a writable memory that is used as a read area for the processor's execution program or as a work area for writing processing data for the execution program. The chipset connects to the host system 40 and other devices via wires and controls the input and output of various types of data.

[0054] The video subsystem 43 processes drawing commands from the host system 40 and outputs display data indicating various display information obtained through the processing to a display 44 . The display 44 displays a display screen based on the display data output from the video subsystem 43 .

[0055] The external memory 52 persistently stores various data in a rewritable manner. The stored data includes various programs, parameters, data used in various processes, and data obtained by various processes. The external memory 52 may be, for example, either an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The input / output I / F 56 is connected to other devices via a wired or wireless connection to input and output various data. The connection to other devices may be via a communication network.

[0056] The EC 61 is a one-chip microcomputer that monitors and controls the status of various devices (peripheral devices, sensors, etc.) regardless of the operating state of the host system 40. The input device 62 and the power supply circuit 1 are connected to the EC 61, and the EC 61 can control the operations of these devices.

[0057] The input device 62 detects a user's operation and outputs an operation signal corresponding to the detected operation to the EC 61. The input device 62 includes, for example, a keyboard and a touchpad. The power supply circuit 1 converts the voltage of DC power supplied from the AC adapter 64 or the battery 66 into a voltage required for the operation of each device constituting the electronic device D1, and supplies the power having the converted voltage to the destination device. The power supply circuit 1 executes power supply in accordance with the control of the EC 61. When power is being supplied from the AC adapter 64, the power supply circuit 1 stores the remaining power not supplied to each device in the battery 66. When power is not being supplied from the AC adapter 64 or when the power supplied from the AC adapter 64 is insufficient, the power discharged from the battery 66 is supplied to each device as operating power. The AC adapter 64 converts AC power supplied from an external power source into DC power with a constant voltage, and supplies the converted power to the power supply circuit 1. The battery 66 includes a secondary battery. The secondary battery is a storage battery that can be charged and discharged. An example of the secondary battery is a lithium-ion battery.

[0058] As described above, the power supply circuit 1 according to this embodiment is a power supply circuit 1 that converts a single input voltage into a plurality of output voltage stages, and includes one or more switched capacitors (e.g., switched capacitors 21, 21S, 22) that can transform the input voltage at one or more transformation ratios, and that apply a lower transformation ratio as the input voltage increases, and one or more regulators (e.g., high-voltage output regulator 25, low-voltage output regulator 26) that adjust an intermediate voltage based on the output power from the switched capacitors to the output voltage. Alternatively, the input voltage may be a discharge voltage of the battery, and the switched capacitor may determine a transformation ratio based on the configuration of the battery. With this configuration, the output voltage from the switched capacitor is leveled even if the input voltage is variable. Because the intermediate voltage input to the regulator is based on the output voltage from the switched capacitor, the difference between the intermediate voltage and the output voltage is reduced. This improves the voltage conversion efficiency of the entire power supply circuit 1, including the regulator.

[0059] The one or more switched capacitors may include a first switched capacitor (e.g., switched capacitor 21) capable of stepping up an input voltage at a predetermined step-up ratio and a second switched capacitor (e.g., switched capacitor 22) capable of stepping down an input voltage at a predetermined step-down ratio. The first switched capacitor steps up the input voltage when the input voltage is lower than a first reference voltage, and the second switched capacitor steps down the input voltage when the input voltage is higher than a second reference voltage. The one or more regulators include a first regulator (e.g., high-voltage output regulator 25) that adjusts a first intermediate voltage based on a first output power from the first switched capacitor to a first output voltage that is a portion of the output voltage, and a second regulator (e.g., low-voltage output regulator 26) that adjusts a second intermediate voltage based on a second output power from the second switched capacitor to a second output voltage that is another portion of the output power. The input voltage may be a discharge voltage of the battery, and the first reference voltage or the second reference voltage may be set based on the discharge voltage when the remaining amount of the battery is a predetermined reference remaining amount.

[0060] With this configuration, when adjusting to a first output voltage, a different first regulator is used separately from a second regulator for adjusting to a lower second output voltage. Furthermore, when the input voltage is lower than the first reference voltage, the input voltage to the first regulator is boosted to obtain a first intermediate voltage to be supplied to the first regulator, and when the input voltage is higher than the second reference voltage, the input voltage to the second regulator is stepped down to obtain a second intermediate voltage to be supplied to the second regulator. This further reduces the difference between the input voltage and output voltage of each regulator, thereby improving voltage conversion efficiency.

[0061] With this configuration, the first switched capacitor starts boosting when the input voltage, which depends on the remaining battery charge, falls below the first reference voltage, and the second switched capacitor stops stepping down when the input voltage falls below the second reference voltage. Because the difference between the input voltage and output voltage in each regulator is further reduced, the voltage conversion efficiency can be further improved.

[0062] The power supply circuit according to this embodiment may be configured as an integrated circuit (for example, a PMIC) that includes one or more switched capacitors and one or more regulators. This embodiment may also be configured as an electronic device D1 that includes a battery 66 and a power supply circuit.

[0063] Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configurations are not limited to the above-described embodiments, and the present invention also includes designs that do not deviate from the gist of the present invention. The configurations described in the above-described embodiments can be combined in any manner. [Explanation of symbols]

[0064] 1...power supply circuit, 10...EN signal generation circuit, 20...logic PMIC, 21, 21S, 22...switched capacitor, 22d...driver circuit, 23...transformer, 25...high-voltage output regulator, 26...low-voltage output regulator, 30...backlight PMIC, 40...host system, 43...video subsystem, 44...display, 52...external memory, 56...input / output I / F, 61...EC, 62...input device, 64...AC adapter, 66...battery, C1, C2...capacitive element, D1...electronic device, SW1, SW2, SW3, SW4...switching element

Claims

1. A power supply circuit that converts a single input voltage into multiple output voltages, The input voltage can be transformed at one or more transformation ratios, one or more switched capacitors that apply a lower transformation ratio as the input voltage increases; and one or more regulators that adjust an intermediate voltage based on an output power from the switched capacitors to the output voltage, The one or more switched capacitors a first switched capacitor capable of boosting the input voltage at a predetermined boost ratio; a second switched capacitor capable of stepping down the input voltage at a predetermined step-down ratio; The first switched capacitor is boosting the input voltage when the input voltage is lower than a predetermined first reference voltage; The second switched capacitor is When the input voltage is higher than a predetermined second reference voltage, the input voltage is lowered; The one or more regulators a first regulator that adjusts a first intermediate voltage based on a first output power from the first switched capacitor to a first output voltage that is a portion of the output voltage; a second regulator that adjusts a second intermediate voltage based on a second output power from the second switched capacitor to a second output voltage that is another portion of the output power. power circuit.

2. the input voltage is a discharge voltage of a battery, The one or more switched capacitors The transformation ratio is determined based on the number of cells connected in series that constitute the battery.

2. The power supply circuit according to claim 1.

3. a step-down converter that steps down the second output power from the second switched capacitor; or a booster that boosts the first output power from the first switched capacitor 2. The power supply circuit according to claim 1.

4. the one or more switched capacitors; the one or more regulators, 2. The power supply circuit according to claim 1.

5. A battery, The power supply circuit according to claim 1 electronic equipment.

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