A voltage reduction circuit and power management device

Abstract

This application provides a step-down circuit and power management device, belonging to the field of analog circuit technology. The step-down circuit includes: a voltage input terminal, a voltage output terminal, a step-down module, and a control module; the step-down module includes: multiple switching components, a first capacitor, a second capacitor, and an inductor; the first terminal of the first switching component is connected to the voltage input terminal, the second terminal of the first switching component is connected to the first terminal of a third switching component, the second terminal of the third switching component is connected to the first terminal of a fifth switching component, and the second terminal of the fifth switching component is connected to the voltage output terminal; the output terminal of the control module is connected to the control terminals of each switching component. This application can reduce the complexity of the circuit system using fewer circuit components and can achieve voltage step-down in power circuits of small portable and wearable electronic devices.

Description

Technical Field

[0001] This application relates to the field of analog circuit technology, and more specifically, to a step-down circuit and a power management device. Background Technology

[0002] With the continuous development of electronic technology, the size of portable and wearable electronic devices is constantly decreasing, thus requiring power management devices with high current density. Such power management devices usually require step-down circuits to reduce voltage.

[0003] In existing technologies, voltage reduction is typically achieved using switched capacitor circuits or buck converter circuits. Switched capacitor circuits require multiple capacitors to achieve voltage reduction, while buck converter circuits require large inductors.

[0004] However, multiple switched capacitors increase the complexity of the entire circuit system, and large inductors are not suitable for small portable and wearable electronic devices, thus limiting the applicability of the circuit. Summary of the Invention

[0005] The purpose of this application is to provide a step-down circuit and power management device that can reduce the complexity of the circuit system by using fewer circuit components, and can step down the power circuit of small portable and wearable electronic devices.

[0006] The embodiments of this application are implemented as follows:

[0007] One aspect of this application provides a step-down circuit, including: a voltage input terminal, a voltage output terminal, a step-down module, and a control module; the step-down module includes: multiple switching components, a first capacitor, a second capacitor, and an inductor.

[0008] The first terminal of the first switching assembly is connected to the voltage input terminal, the second terminal of the first switching assembly is connected to the first terminal of the third switching assembly, the second terminal of the third switching assembly is connected to the first terminal of the fifth switching assembly, and the second terminal of the fifth switching assembly is connected to the voltage output terminal.

[0009] The first terminal of the second switching assembly is grounded, the second terminal of the second switching assembly is connected to the first terminal of the inductor, and the second terminal of the inductor is connected to the voltage output terminal.

[0010] The first terminal of the first capacitor is connected to the second terminal of the first switching assembly, and the second terminal of the first capacitor is connected to the second terminal of the second switching assembly.

[0011] The first terminal of the second capacitor is connected to the second terminal of the third switch assembly, and the second terminal of the second capacitor is connected to the second terminal of the fourth switch assembly and the first terminal of the sixth switch assembly, respectively.

[0012] The first terminal of the fourth switching assembly is grounded, and the second terminal of the sixth switching assembly is connected to the voltage output terminal.

[0013] The input terminal of the control module is connected to the voltage output terminal, and the output terminal of the control module is connected to the control terminal of each switching component.

[0014] Optionally, the control module includes: a voltage processing unit, a mode selection unit, and a control drive unit;

[0015] The input terminal of the voltage processing unit is connected to the second terminal of the fifth switching assembly and the second terminal of the inductor element, and the output terminal of the voltage processing unit is connected to the input terminal of the mode selection unit. The voltage processing unit is used to preprocess the voltage signal.

[0016] The output of the mode selection unit is connected to the control drive unit. The mode selection unit is used to determine the target control drive mode based on the preprocessed voltage signal.

[0017] The output of the control drive unit is connected to each switch component, and the drive control unit is used to control the opening and closing of the switch components in the corresponding mode based on the target control drive mode.

[0018] Optionally, the voltage processing unit includes: an error amplifier, a first comparator, and a reset position trigger;

[0019] The first input terminal of the error amplifier is connected to the voltage output terminal, and the second input terminal of the error amplifier is used to input the first reference voltage; the output terminal of the error amplifier is used to send the error amplification result to the first input terminal of the first comparator.

[0020] The second input terminal of the first comparator is used to input the ramp voltage, and the output terminal of the first comparator is used to send the first comparison result to the first input terminal of the reset position trigger.

[0021] The second input terminal of the reset position flip-flop is used to input the first clock signal, and the output terminal of the reset position flip-flop is used to send the trigger result to the mode selection unit.

[0022] Optionally, the voltage processing unit further includes: a ramp generator;

[0023] The ramp generator is connected to the second input terminal of the first comparator, the second input terminal of the reset position trigger, and the input terminal of the mode selection unit, respectively.

[0024] The ramp generator is used to provide ramp voltage for the first comparator, a first clock signal for the reset trigger, and a second clock signal for the mode selection unit.

[0025] Optionally, the voltage processing unit further includes: a second comparator, a first resistor, and a second resistor;

[0026] The first end of the first resistor is connected to the voltage input terminal, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is grounded.

[0027] The first input terminal of the second comparator is connected to the second terminal of the first resistor. The second input terminal of the second comparator is used to input the second reference voltage. The output terminal of the second comparator is used to send the second comparison result to the mode selection unit.

[0028] Optionally, the mode selection unit is a digital mode selector. The digital mode selector is used to receive the second comparison result, trigger result, and second clock signal sent by the voltage processing unit to perform mode selection processing, and to send the selected mode information and duty cycle to the control drive unit.

[0029] Optionally, the switching component is a single field-effect transistor (FET), or the switching component is a switch composed of multiple FETs connected in series.

[0030] Optionally, the step-down circuit may further include a third capacitor, the first terminal of which is connected to the voltage output terminal, and the second terminal of which is grounded.

[0031] In another aspect of this application, a power management device is provided, which includes a step-down circuit and an associated module.

[0032] The beneficial effects of the embodiments of this application include:

[0033] The buck circuit and power management device provided in this application embodiment may include: a voltage input terminal, a voltage output terminal, a buck module, and a control module; the buck module includes: multiple switching components, a first capacitor, a second capacitor, and an inductor; the first terminal of the first switching component is connected to the voltage input terminal, the second terminal of the first switching component is connected to the first terminal of the third switching component, the second terminal of the third switching component is connected to the first terminal of the fifth switching component, and the second terminal of the fifth switching component is connected to the voltage output terminal; the first terminal of the second switching component is grounded, the second terminal of the second switching component is connected to the first terminal of the inductor, and the second terminal of the inductor is connected to the voltage output terminal; the first terminal of the first capacitor is connected to the second terminal of the first switching component, and the second terminal of the first capacitor is connected to the second terminal of the second switching component; the first terminal of the second capacitor is connected to the second terminal of the third switching component, and the second terminal of the second capacitor is connected to the second terminal of the fourth switching component and the first terminal of the sixth switching component respectively; the first terminal of the fourth switching component is grounded, and the second terminal of the sixth switching component is connected to the voltage output terminal; the input terminal of the control module is connected to the voltage output terminal, and the output terminal of the control module is connected to the control terminal of each switching component respectively. The circuit structure of the aforementioned step-down circuit can significantly reduce the inductor current. Therefore, with low inductor current, a small inductor can be used, which can improve the circuit's efficiency, reduce the overall size of the circuit system, and decrease the complexity of the circuit system. It can also enable step-down processing of power circuits in small portable and wearable electronic devices. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic diagram of the step-down circuit provided in the embodiments of this application. Figure 1 ;

[0036] Figure 2 This is a schematic diagram of the structure of the control module provided in an embodiment of this application;

[0037] Figure 3 This is a schematic diagram of the voltage processing unit provided in an embodiment of this application;

[0038] Figure 4 A schematic diagram of the step-down circuit provided in the embodiments of this application. Figure 2 ;

[0039] Figure 5A schematic diagram of the operation of the step-down circuit provided in the embodiments of this application. Figure 1 ;

[0040] Figure 6 A schematic diagram of the operation of the step-down circuit provided in the embodiments of this application. Figure 2 ;

[0041] Figure 7 This is a schematic diagram of the power management device provided in an embodiment of this application.

[0042] Icons: 10 - Buck converter; 20 - Associated module; 100 - Voltage input; 200 - Voltage output; 300 - Buck module; 400 - Control module; 410 - Voltage processing unit; 420 - Mode selection unit; 430 - Control drive unit; 411 - Error amplifier; 412 - First comparator; 413 - Reset trigger; 414 - Ramp generator; 415 - Second comparator;

[0043] S1 - First switch assembly; S2 - Second switch assembly; S3 - Third switch assembly; S4 - Fourth switch assembly; S5 - Fifth switch assembly; S6 - Sixth switch assembly; C1 - First capacitor; C2 - Second capacitor; C3 - Third capacitor; R1 - First resistor; R2 - Second resistor; L - Inductor. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0046] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0047] In the description of this application, it should be noted that the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0048] With the continuous development of electronic circuit technology, the size of portable and wearable electronic devices is constantly decreasing, thus requiring power management devices with high current density.

[0049] Switched-capacitor (SC) and buck converter (Buck) circuits are two commonly used solutions. Switched capacitors can achieve high current density and high efficiency at a specific voltage conversion ratio (VCR). However, to cover a wide input-output voltage range, reconfigurable multi-VCR switched capacitors are required, which increases system complexity. On the other hand, traditional Buck circuits can achieve good efficiency over a wide continuous VCR range. However, they require a bulky inductor, which significantly reduces the system's current density.

[0050] To address the trade-off between current density and efficiency, a flying capacitor multilevel (FCML) voltage converter using both capacitors and inductors has been proposed and studied. Compared to traditional Buck circuits that use only inductors, this hybrid circuit exhibits a smaller inductor voltage variation range, a higher switching frequency, and a larger duty cycle (D) for the same VCR switching signal. This reduces the inductor requirements and thus achieves higher current density.

[0051] However, since all the output current flows through the inductor, the inductor must maintain a relatively large volume to obtain a small DC resistance (DCR), thereby reducing conduction losses.

[0052] In hybrid circuits that reduce inductor current, switched capacitors not only lower the node voltage of the switch but also provide an additional current path to the output, reducing the inductor current. However, problems such as limited VCR range or large inductor current ripple diminish the benefits of reducing inductor current.

[0053] The following section will explain in detail the specific structure of the step-down circuit provided in the embodiments of this application and the connection relationship of the related electronic components therein.

[0054] Figure 1 A schematic diagram of the step-down circuit provided in the embodiments of this application. Figure 1 Please refer to Figure 1 The step-down circuit includes: a voltage input terminal 100, a voltage output terminal 200, a step-down module 300, and a control module 400; the step-down module 300 includes: multiple switching components, a first capacitor C1, a second capacitor C2, and an inductor L.

[0055] The first terminal of the first switching assembly S1 is connected to the voltage input terminal 100. The second terminal of the first switching assembly S1 is connected to the first terminal of the third switching assembly S3. The second terminal of the third switching assembly S3 is connected to the first terminal of the fifth switching assembly S5. The second terminal of the fifth switching assembly S5 is connected to the voltage output terminal 200. The first terminal of the second switching assembly S2 is grounded. The second terminal of the second switching assembly S2 is connected to the first terminal of the inductor L. The second terminal of the inductor L is connected to the voltage output terminal 200. The first terminal of the first capacitor C1 is connected to the second terminal of the first switching assembly S1. The second terminal of the first capacitor C1 is connected to the second terminal of the second switching assembly S2. The first terminal of the second capacitor C2 is connected to the second terminal of the third switching assembly S3. The second terminal of the second capacitor C2 is connected to the second terminal of the fourth switching assembly S4 and the first terminal of the sixth switching assembly S6, respectively. The first terminal of the fourth switching assembly S4 is grounded. The second terminal of the sixth switching assembly S6 is connected to the voltage output terminal 200.

[0056] Optionally, the input terminal of the control module 400 is connected to the voltage output terminal 200, and the output terminal of the control module 400 is connected to the control terminal of each switching component.

[0057] Optionally, the switching assembly includes: a first switching assembly S1, a second switching assembly S2, a third switching assembly S3, a fourth switching assembly S4, a fifth switching assembly S5, and a sixth switching assembly S6. Each switching assembly can be a switching device used to connect or disconnect a circuit.

[0058] Optionally, both the first capacitor C1 and the second capacitor C2 can be flying capacitors set in the circuit, and the inductor L can be a small-volume inductor with low inductance current, which can be used in micro-circuits.

[0059] It should be noted that the embodiments in this application are for applications that step down and convert lithium battery voltage (2.8-4.2V) to below 1V, therefore two flying capacitors C1 and C2 are used. For applications with other voltage conversion ratios, one flying capacitor or three or more flying capacitors can also be used, and no specific limitation is made here.

[0060] Optionally, the step-down module 300 can reduce the voltage during operation, that is, make the voltage at the voltage output terminal 200 lower than the voltage at the voltage input terminal 100. Depending on the actual needs, the voltage can be reduced in a ratio of 1 / 2 or 1 / 3.

[0061] Optionally, the control module 400 can perform closed-loop adjustment based on the output voltage of the step-down module 300, thereby controlling the connection or disconnection of the aforementioned switching components based on the adjustment result.

[0062] Optionally, the step-down process may include two processes: the charging process of the inductor (Φ1) and the discharging process of the inductor (Φ2). The output voltage can be obtained after the above two processes. The output voltage is the voltage obtained after the input voltage is stepped down.

[0063] The step-down circuit provided in this application embodiment may include: a voltage input terminal, a voltage output terminal, a step-down module, and a control module; the step-down module includes: multiple switching components, a first capacitor, a second capacitor, and an inductor; the first terminal of the first switching component is connected to the voltage input terminal, the second terminal of the first switching component is connected to the first terminal of the third switching component, the second terminal of the third switching component is connected to the first terminal of the fifth switching component, and the second terminal of the fifth switching component is connected to the voltage output terminal; the first terminal of the second switching component is grounded, the second terminal of the second switching component is connected to the first terminal of the inductor, and the second terminal of the inductor is connected to the voltage output terminal; the first terminal of the first capacitor is connected to the second terminal of the first switching component, and the second terminal of the first capacitor is connected to the second terminal of the second switching component; the first terminal of the second capacitor is connected to the second terminal of the third switching component, and the second terminal of the second capacitor is connected to the second terminal of the fourth switching component and the first terminal of the sixth switching component respectively; the first terminal of the fourth switching component is grounded, and the second terminal of the sixth switching component is connected to the voltage output terminal; the input terminal of the control module is connected to the voltage output terminal, and the output terminal of the control module is connected to the control terminal of each switching component respectively. The circuit structure of the aforementioned step-down circuit can significantly reduce the inductor current. Therefore, with low inductor current, a small inductor can be used, which can improve the circuit's efficiency, reduce the overall size of the circuit system, and decrease the complexity of the circuit system. It can also enable step-down processing of power circuits in small portable and wearable electronic devices.

[0064] In addition, the step-down circuit provided in this application uses a small-sized inductor, so the inductor current ripple is also small; in addition, due to its circuit structure, it can achieve continuous high efficiency over a wide VCR range; and the use of a specific flying capacitor setting method eliminates the need for voltage balancing processing of the flying capacitor.

[0065] The specific structure of the control module in the step-down circuit provided in the embodiments of this application will be explained in detail below.

[0066] Figure 2 Please refer to the schematic diagram of the control module provided in the embodiments of this application. Figure 2 The control module 400 includes: a voltage processing unit 410, a mode selection unit 420, and a control drive unit 430;

[0067] The input terminal of the voltage processing unit 410 is connected to the second terminal of the fifth switching component S5 and the second terminal of the inductor L. The output terminal of the voltage processing unit 410 is connected to the input terminal of the mode selection unit 420. The voltage processing unit 410 is used to preprocess the voltage signal. The output terminal of the mode selection unit 420 is connected to the control drive unit 430. The mode selection unit 420 is used to determine the target control drive mode based on the preprocessed voltage signal. The output terminal of the control drive unit 430 is connected to each switching component. The control drive unit 430 is used to control the opening and closing of the switching components in the corresponding mode based on the target control drive mode.

[0068] Optionally, the voltage processing unit 410 can acquire the output voltage of the buck module 300, and based on this voltage, it can perform various processing methods such as error amplification, comparison, and triggering in sequence, and send the processed voltage signal to the mode selection unit 420.

[0069] The mode selection unit 420 can determine the mode based on the preprocessed voltage signal, such as determining whether the current circuit is in 1 / 3 buck mode or 1 / 2 buck mode. Under the same buck mode, it can also determine whether it is in the inductor charging process or the inductor discharging process, and then determine the target control drive mode according to the corresponding mode.

[0070] The control drive unit 430 can determine the on and off of each switch component based on the target control drive mode. For different target control drive modes, the on and off of the switch components can be different.

[0071] Optionally, in this embodiment, the control drive unit 430 may be provided with six output terminals, each corresponding to the control terminal of the aforementioned six switching components.

[0072] The specific structural connection relationship of the voltage processing unit provided in the embodiments of this application will be explained in detail below.

[0073] Figure 3 Please refer to the schematic diagram of the voltage processing unit provided in the embodiments of this application. Figure 3The voltage processing unit 410 includes: an error amplifier 411, a first comparator 412, and a reset trigger 413; the first input terminal of the error amplifier 411 is connected to the voltage output terminal 200, and the second input terminal of the error amplifier 411 is used to input a first reference voltage; the output terminal of the error amplifier 411 is used to send the error amplification result to the first input terminal of the first comparator 412; the second input terminal of the first comparator 412 is used to input a ramp voltage, and the output terminal of the first comparator 412 is used to send the first comparison result to the first input terminal of the reset trigger 413; the second input terminal of the reset trigger 413 is used to input a first clock signal, and the output terminal of the reset trigger 413 is used to send the trigger result to the mode selection unit 420.

[0074] Optionally, the error amplifier 411 may compare the difference between the input voltage signal and the first reference voltage, amplify the difference voltage obtained by comparison according to a preset amplification ratio, and send the obtained error amplification result to the first comparator 412.

[0075] Optionally, the first comparator 412 can compare the input error amplification result with the ramp voltage to obtain a first comparison result. After obtaining the first comparison result, it can be sent to the reset position trigger 413.

[0076] Optionally, the reset trigger 413, i.e., the R (reset) S (set) trigger, can be triggered based on the first comparison result and the first clock signal to obtain the trigger result, and can send the trigger result to the mode selection unit 420.

[0077] Optionally, the voltage processing unit 410 further includes: a ramp generator 414; the ramp generator 414 is connected to the second input terminal of the first comparator 412, the second input terminal of the reset position trigger 413, and the input terminal of the mode selection unit 420, respectively; the ramp generator 414 is used to provide ramp voltage for the first comparator 412, a first clock signal for the reset position trigger 413, and a second clock signal for the mode selection unit 420.

[0078] Optionally, the ramp generator 414 may be an electronic component for generating ramp and clock signals, providing ramp voltage to the first comparator 412 and a first clock signal to the reset trigger 413.

[0079] Optionally, the mode selection unit 420 requires two additional clock signals for mode determination during operation, namely, the second clock signal. In the embodiments of this application, there can be two second clock signals, namely clock signals with duty cycles of 80% and 42%. It should be noted that the above specific values ​​are only an example. In the actual circuit structure, the values ​​of the clock signals can be set according to actual needs and are not limited to this.

[0080] Optionally, the voltage processing unit 410 further includes: a second comparator 415, a first resistor R1, and a second resistor R2; the first end of the first resistor R1 is connected to the voltage input terminal 100, the second end of the first resistor R1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is grounded; the first input terminal of the second comparator 415 is connected to the second end of the first resistor R1, the second input terminal of the second comparator 415 is used to input a second reference voltage, and the output terminal of the second comparator 415 is used to send the second comparison result to the mode selection unit 420.

[0081] Optionally, the second comparator 415 can be used to compare the input voltage after resistor voltage division with the second reference voltage to obtain a second comparison result, which can also be input to the mode selection unit 420.

[0082] Optionally, the mode selection unit 420 is a digital mode selector. The digital mode selector is used to receive the second comparison result, trigger result, and second clock signal sent by the voltage processing unit to perform mode selection processing, and to send the selected mode information and duty cycle to the control drive unit.

[0083] Optionally, the mode selection unit 420 can be a four-input dual-output digital mode selector, wherein the inputs can be the second comparison result (the result obtained by processing the input voltage as described above), the trigger result (the result obtained by processing the output voltage as described above), and two clock signals (two clock signals with duty cycles of 80% and 42%) from the second clock signal.

[0084] Optionally, the output may specifically be the selected mode information (i.e., the specific working mode) and the duty cycle (duty cycle D, specifically a number between 0 and 1) sent to the control drive unit.

[0085] Optionally, the mode selection unit 420 can preliminarily determine the operating mode based on the second comparison result. In the second comparator, the input voltage V can be determined. IN Second reference voltage V REF The ratio, which is the second comparison result, allows the mode selection unit 420 to determine whether to use the 1 / 3 buck mode or the 1 / 2 buck mode based on the value of the second comparison result. For example, when VREF / V IN A value less than 0.29 indicates the need for a 1 / 3 buck mode; correspondingly, when V... REF / V IN If the value is greater than or equal to 0.29, it can be determined that the 1 / 2 buck mode is adopted. This buck mode is the mode information selected above. The mode selection unit 420 can send this mode to the control drive unit 430.

[0086] Optionally, the mode selection unit 420 can also obtain the duty cycle D based on the trigger result and the second clock signal, and can send the specific value of D to the control drive unit 430 in real time during operation.

[0087] Optionally, the control drive unit 430 can switch the operating mode according to the specific value of D. For example, when in 1 / 3 buck mode, if D is greater than the first threshold for a period of time, it will switch to 1 / 2 buck mode. Similarly, in 1 / 2 buck mode, if D is less than the second threshold for a period of time, it will switch to 1 / 3 buck mode.

[0088] It should be noted that the specific coefficients of the first threshold and the second threshold can be determined by the second clock signal mentioned above. For example, when the duty cycle is 80% and 42%, the first threshold can be 0.8 and the second threshold can be 0.42. The specific values ​​can be set according to actual needs and are not limited to these values.

[0089] The following section will explain another specific structural connection relationship of the step-down circuit provided in the embodiments of this application.

[0090] Figure 4 A schematic diagram of the step-down circuit provided in the embodiments of this application. Figure 2 Please refer to Figure 4 The switching component is a single field-effect transistor (FET), or the switching component is a switch composed of multiple FETs connected in series.

[0091] Optionally, S1 can be implemented by stacking two 2.5V PMOS transistors in series, S2 and S3 can be implemented by stacking one 2.5V and one 1V NMOS transistor in series, and S4, S5 and S6 can be implemented by a 1V NMOS transistor.

[0092] It should be noted that the embodiments in this application use a field-effect transistor as an example. In actual use, transistors, switching transistors, or any other type of switching device can be used (e.g., gallium nitride, silicon carbide, and other transistors), and are not limited thereto.

[0093] Optionally, the step-down circuit 10 further includes a third capacitor C3, the first end of which is connected to the voltage output terminal 200, and the second end of which is grounded.

[0094] Optionally, the third capacitor C3 can be a capacitor used to stabilize the output voltage.

[0095] The working principle of the step-down circuit provided in the embodiments of this application under different working modes will be explained in detail below.

[0096] Figure 5 A schematic diagram of the operation of the step-down circuit provided in the embodiments of this application. Figure 1 Please refer to Figure 5 , Figure 5 The diagram shows the circuit operation when the voltage conversion ratio (output voltage to input voltage) is at most 1 / 3. Under this condition, during Φ1 (charging), switches S1, S4, and S5 are open, and S2, S3, and S6 are closed. The first capacitor C1 and the inductor L are charged in series, while the second capacitor C2 discharges to the voltage output terminal. During Φ2 (discharging), switches S1, S4, and S5 are closed, and S2, S3, and S6 are open. The first capacitor C1 charges the second capacitor C2, while the inductor L discharges to the voltage output terminal.

[0097] Calculations show that the voltage across the two flying capacitors is V. C1 =2V OUT V C2 =V OUT Output voltage V OUT =DV IN / (1+2D), inductor current I L =I OUT / (1+2D).

[0098] Among them, V C1 V is the voltage across the first capacitor. C2 V is the voltage across the second capacitor. IN V is the input voltage. OUT For the output voltage, I L I is the inductor current. OUT The output current is represented by D, which is the duty cycle as mentioned above.

[0099] In this circuit, the inductor current is significantly reduced; for example, when D is 0.5, I... L =0.5I OUT The inductor current is reduced to half of the output current, and the conduction loss on the inductor is reduced to 25% of its original value. In this mode, the theoretical maximum output voltage is V. IN / 3.

[0100] Figure 6 A schematic diagram of the operation of the step-down circuit provided in the embodiments of this application. Figure 2 Please refer to Figure 6 , Figure 6The diagram shows the circuit operation when the voltage conversion ratio is at most 1 / 2. Under this condition, switches S4 and S5 remain open, and S6 remains closed. At Φ1, switch S1 is open, and S2 and S3 are closed, charging the first capacitor C1 and the inductor L in series. At Φ2, switch S1 is closed, and S2 and S3 are open, discharging the first capacitor C1 to the output, while simultaneously discharging the inductor L to the output.

[0101] Calculations show that the voltage across the two flying capacitors is V. C1 =V C2 =V OUT Output voltage V OUT =DV IN / (1+D), inductor current I L =I OUT / (1+D).

[0102] It can be deduced that, theoretically, the maximum output voltage in this circuit is V. IN / 2.

[0103] The following section will explain the specific structural diagram of the power management device provided in the embodiments of this application.

[0104] Figure 7 Please refer to the schematic diagram of the power management device provided in the embodiments of this application. Figure 7 The power management device includes a step-down circuit 10 and an associated module 20.

[0105] The step-down circuit 10 can be connected to at least one associated module 20, wherein the associated module can be a related processing module disposed in the power supply circuit, such as a related module in a lithium-ion battery, to assist the step-down circuit 10 in realizing the operation of the power management device.

[0106] Specifically, the power management device can be a device structure composed of power circuits in a battery or other power supply equipment.

[0107] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0108] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A step-down circuit, characterized in that, include: Voltage input terminal, voltage output terminal, step-down module, control module; The step-down module includes: multiple switching components, a first capacitor, a second capacitor, and an inductor; The first terminal of the first switching assembly is connected to the voltage input terminal, the second terminal of the first switching assembly is connected to the first terminal of the third switching assembly, the second terminal of the third switching assembly is connected to the first terminal of the fifth switching assembly, and the second terminal of the fifth switching assembly is connected to the voltage output terminal. The first terminal of the second switching assembly is grounded, the second terminal of the second switching assembly is connected to the first terminal of the inductor, and the second terminal of the inductor is connected to the voltage output terminal. The first terminal of the first capacitor is connected to the second terminal of the first switching assembly, and the second terminal of the first capacitor is connected to the second terminal of the second switching assembly. The first terminal of the second capacitor is connected to the second terminal of the third switch assembly, and the second terminal of the second capacitor is connected to the second terminal of the fourth switch assembly and the first terminal of the sixth switch assembly, respectively. The first terminal of the fourth switch assembly is grounded, and the second terminal of the sixth switch assembly is connected to the voltage output terminal. The input terminal of the control module is connected to the voltage output terminal, and the output terminal of the control module is connected to the control terminal of each of the switching components respectively. The control module includes a voltage processing unit, a mode selection unit, and a control drive unit. The input terminal of the voltage processing unit is connected to the second terminal of the fifth switching component and the second terminal of the inductor. The output terminal of the voltage processing unit is connected to the input terminal of the mode selection unit. The voltage processing unit is used to preprocess the voltage signal. The output terminal of the mode selection unit is connected to the control drive unit. The mode selection unit is used to determine a target control drive mode based on the preprocessed voltage signal. The output terminal of the control drive unit is connected to each of the switching components. The control drive unit is used to control the opening and closing of the switching components in the corresponding mode based on the target control drive mode. The voltage processing unit includes: an error amplifier, a first comparator, and a reset trigger; the first input terminal of the error amplifier is connected to the voltage output terminal, and the second input terminal of the error amplifier is used to input a first reference voltage; the output terminal of the error amplifier is used to send the error amplification result to the first input terminal of the first comparator; the second input terminal of the first comparator is used to input a ramp voltage, and the output terminal of the first comparator is used to send a first comparison result to the first input terminal of the reset trigger; the second input terminal of the reset trigger is used to input a first clock signal, and the output terminal of the reset trigger is used to send the trigger result to the mode selection unit.

2. The step-down circuit as described in claim 1, characterized in that, The voltage processing unit further includes: a ramp wave generator; The ramp generator is connected to the second input terminal of the first comparator, the second input terminal of the reset trigger, and the input terminal of the mode selection unit, respectively. The ramp generator is used to provide ramp voltage for the first comparator, a first clock signal for the reset trigger, and a second clock signal for the mode selection unit.

3. The step-down circuit as described in claim 1, characterized in that, The voltage processing unit further includes: a second comparator, a first resistor, and a second resistor; The first end of the first resistor is connected to the voltage input terminal, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is grounded. The first input terminal of the second comparator is connected to the second terminal of the first resistor, the second input terminal of the second comparator is used to input the second reference voltage, and the output terminal of the second comparator is used to send the second comparison result to the mode selection unit.

4. The step-down circuit as described in claim 1, characterized in that, The mode selection unit is a digital mode selector. The digital mode selector is used to receive the second comparison result, trigger result, and second clock signal sent by the voltage processing unit, perform mode selection processing, and send the selected mode information and duty cycle to the control drive unit.

5. The step-down circuit as described in claim 1, characterized in that, The switching component is a single field-effect transistor (FET), or the switching component is a switch composed of multiple FETs connected in series.

6. The step-down circuit as described in claim 1, characterized in that, The step-down circuit further includes a third capacitor, the first end of which is connected to the voltage output terminal, and the second end of which is grounded.

7. A power management device, characterized in that, The power management device includes a step-down circuit as described in any one of claims 1-6 and an associated module.

Images