DC-DC converter and method for improving voltage conversion speed

Abstract

The invention provides a direct current-direct current converter and method for improving voltage conversion speed. The converter comprises a power supply, a power level circuit and an output switch capacitor unit, the power supply provides input voltage as an energy supply end; the two input ends of the power level circuit are connected with a power supply, the two output ends of the power level circuit are connected to the two ends of a load, and the power level circuit is configured to transmit energy provided by the power supply to the load and can convert input voltage to adjust power supply voltage of the load; the output switched capacitor unit is connected between the two output ends of the power level circuit and comprises a plurality of switched capacitor branches which are arranged in parallel; wherein each switched capacitor branch is configured to have different capacitor voltage range intervals, so that the switched capacitor branch is gated according to the capacitor voltage range interval corresponding to each switched capacitor branch when the working state of the load changes, and the power supply voltage of the load is changed more quickly and stably.

Description

Technical Field

[0001] This disclosure relates to the field of circuit design technology, and in particular to a DC-DC converter and method for improving voltage conversion speed. Background Technology

[0002] Due to changes in load operating conditions, DC-DC converters need to provide different supply voltages to the load accordingly. For example, power amplifiers in communication systems require high supply voltages for high output power and lower supply voltages for low power to reduce losses. Similarly, computing chips require higher supply voltages for high-load computations and lower supply voltages for simple tasks to reduce losses. However, current DC-DC converters require charging and discharging output capacitors during output voltage conversion, resulting in long conversion times. Figure 1 The image shows an existing DC-DC converter, which includes a power supply and an output capacitor (C). OUT The system includes a power stage circuit module for voltage conversion, comprising inductors, switches, and capacitors. The output capacitor serves to attenuate the switching noise of the DC-DC converter and provide a low-impedance AC grounding path for the load.

[0003] When it is necessary to convert the output voltage, the output capacitor needs to be charged and discharged, and the following constraints must be met:

[0004] (1);

[0005] Where t is the time required to complete the voltage conversion, and C OUT The value of the output capacitor. I represents the change in output voltage before and after the conversion. CH Let C be the average charging current for the capacitor. To address the time constraint required for voltage conversion in equation (1), existing solutions reduce the output capacitor C. OUT Increase the charging current I CH This shortens the time required to complete the voltage conversion. It also reduces the output capacitance C. OUT This approach will result in large output voltage ripple, significant overshoot or undershoot of the output voltage when the load changes, leading to degraded load performance and even functional errors. Increasing the charging current I... CH The proposed solution requires changing the power stage of the converter, which leads to problems such as an increase in the number of power stage components, an increase in chip area and cost, and a decrease in converter efficiency. Summary of the Invention

[0006] In view of the above, in order to at least partially solve at least one of the aforementioned technical problems, this disclosure provides a DC-DC converter and method for improving voltage conversion speed. The technical solution is as follows:

[0007] According to one embodiment of this disclosure, a DC-DC converter for improving voltage conversion speed is provided, including a power supply, a power stage circuit, and an output switched capacitor unit. The power supply provides an input voltage as an energy supply terminal; the two input terminals of the power stage circuit are connected to the power supply, and the two output terminals are connected to the two ends of a load, configured to transfer the energy provided by the power supply to the load and to convert the input voltage to adjust the supply voltage of the load; the output switched capacitor unit is connected between the two output terminals of the power stage circuit, and the output switched capacitor unit includes multiple switched capacitor branches arranged in parallel; wherein each switched capacitor branch is configured to have a different capacitor voltage range, so that when the load operating state changes, the switched capacitor branch is selected according to the capacitor voltage range corresponding to each switched capacitor branch, thereby changing the supply voltage of the load more quickly and stably.

[0008] According to embodiments of this disclosure, each switched capacitor branch includes a capacitor and a switch connected in series between the two output terminals of the power stage circuit.

[0009] According to the embodiments of this disclosure, the capacitor voltage ranges corresponding to each switched capacitor branch are different and do not overlap.

[0010] According to an embodiment of this disclosure, when the load operating state changes, one of the multiple switched capacitor branches is selected based on the capacitor voltage range corresponding to each switched capacitor branch, while the remaining switched capacitor branches are disconnected, and the capacitor remains in a floating state.

[0011] According to embodiments of this disclosure, the sum of the capacitor voltage ranges corresponding to all switched capacitor branches covers the target supply voltage range for the load.

[0012] According to an embodiment of this disclosure, when the operating state of the load changes, the converter power stage circuit charges and discharges the capacitors in the selected switched capacitor branch while providing the current required by the load.

[0013] According to an embodiment of this disclosure, the output switched capacitor unit includes two switched capacitor branches, namely a first switched capacitor branch and a second switched capacitor branch. The sum of the capacitor voltage range of the first switched capacitor branch and the capacitor voltage range of the second switched capacitor branch covers the target supply voltage range of the load.

[0014] According to an embodiment of this disclosure, the output switched capacitor unit includes M switched capacitor branches, where M > 2. The sum of the capacitor voltage range of each switched capacitor branch covers the target power supply voltage range of the load.

[0015] According to an embodiment of this disclosure, the power stage circuit includes a feedback control unit configured to detect the real-time voltage across the load and control the power stage circuit and the output switched capacitor unit based on the real-time voltage to adjust the supply voltage of the load.

[0016] Another embodiment of this disclosure provides a method for improving the voltage conversion speed using the above-described DC-DC converter, comprising: S1: when the load is in a steady state, connecting the capacitor in any switched capacitor branch of the output switched capacitor unit to the two output terminals of the power stage circuit through a switch, while disconnecting the switches in the remaining switched capacitor branches to keep the capacitor floating, and keeping the voltage on the capacitor within the corresponding capacitor voltage range; S2: when the load operating state changes and voltage conversion is required, selecting one switched capacitor branch according to the capacitor voltage range of the target voltage, while disconnecting the switches in all other switched capacitor branches to keep the capacitor floating; and S3: controlling the power stage circuit and the output switched capacitor unit through a feedback control unit to adjust the supply voltage of the load to the target value. Attached Figure Description

[0017] The objects, features, and advantages of this disclosure will become clearer from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0018] Figure 1 This is a schematic diagram of a conventional DC-DC converter.

[0019] Figure 2 This is a schematic diagram of a DC-DC converter for improving voltage conversion speed according to an embodiment of the present disclosure.

[0020] Figure 3 This is a schematic diagram showing the capacitor voltage range of each switched capacitor branch in the DC-DC converter of this embodiment.

[0021] Figure 4 This is a flowchart illustrating a method for improving voltage conversion speed according to an embodiment of the present disclosure.

[0022] Figure 5 This is a schematic diagram of the voltage conversion waveforms of two switched capacitor branches in an embodiment of this disclosure. Detailed Implementation

[0023] This disclosure provides a DC-DC converter and method for improving voltage conversion speed, which shortens the voltage conversion time while ensuring that the output voltage ripple and transient switching performance remain unchanged and without changing the power stage circuit.

[0024] This invention provides a DC-DC converter and method for improving voltage conversion speed. It divides the entire load's supply voltage range (i.e., the converter's output voltage range) into multiple sub-ranges, and correspondingly introduces multiple switched capacitor branches. Each sub-range corresponds to an output capacitor, meaning the voltage across the output capacitor in that switched capacitor branch falls within that sub-range. During voltage conversion, the corresponding output capacitor is first selected based on the sub-range containing the target output voltage, and then the capacitor voltage is adjusted to the target output voltage. In traditional converters, the output capacitor voltage needs to be adjusted across the entire output voltage range; in this solution, the output capacitor only needs adjustment within a sub-range voltage interval, significantly reducing the required charging and discharging charge, thus significantly shortening the voltage conversion time. Therefore, this invention proposes a DC-DC converter with fast output voltage conversion.

[0025] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0026] In this disclosure, a DC-DC converter with improved voltage conversion speed is provided, combined with... Figure 2 and Figure 3 As shown, the DC-DC converter includes a power supply 201, a power stage circuit 202, and an output switched capacitor unit 203. The power supply 201 provides the input voltage as the energy supply terminal. The two input terminals of the power stage circuit 202 are connected to the power supply 201, and the two output terminals are connected to the two ends of the load. It is configured to transfer the energy provided by the power supply to the load and to convert the input voltage to adjust the supply voltage of the load. The output switched capacitor unit 203 is connected between the two output terminals of the power stage circuit 202. The output switched capacitor unit includes multiple switched capacitor branches arranged in parallel, for example, 2, 3, 4, 5, 6, 10, or more switched capacitor branches. Each switched capacitor branch is configured with a different capacitor voltage range, so that when the load operating state changes, the switched capacitor branch is selected according to the corresponding capacitor voltage range, thereby changing the supply voltage of the load more quickly and stably.

[0027] According to embodiments of this disclosure, each switched capacitor branch includes a capacitor and a switch connected in series between the two output terminals of the power stage circuit.

[0028] According to embodiments of this disclosure, the power stage circuit mainly includes inductors, switches, capacitors, etc., used to efficiently transfer energy from the input power supply to the load and complete the conversion from input voltage to output voltage. When the output voltage value needs to change, the converter power stage circuit needs to provide additional current to charge and discharge the output capacitor while providing the current required by the load, thus completing the conversion of the output voltage value.

[0029] According to embodiments of this disclosure, in conjunction with Figure 3 and Figure 2 As shown, the capacitor voltage ranges corresponding to each switched capacitor branch are different. When the load operating state changes, one of the multiple switched capacitor branches is selected based on the capacitor voltage range corresponding to each branch, while the remaining switched capacitor branches are disconnected, and the capacitors remain in a floating state. The sum of the capacitor voltage ranges corresponding to all switched capacitor branches covers the target supply voltage range for the load.

[0030] According to an embodiment of this disclosure, when the operating state of the load changes, the converter power stage circuit provides the required current to the load while simultaneously charging and discharging the capacitors in the selected switched capacitor branch.

[0031] According to embodiments of this disclosure, the output switched capacitor unit may include two switched capacitor branches, namely a first switched capacitor branch and a second switched capacitor branch. The sum of the capacitor voltage ranges of the first and second switched capacitor branches covers the target supply voltage range for the load. For example, if the target supply voltage range for the load is 0 to N volts, where N > 0, then the capacitor voltage range of the first switched capacitor branch can be 0 to N / 2 volts, and the capacitor voltage range of the second switched capacitor branch can be N / 2 to N volts. Alternatively, the capacitor voltage ranges of the first and second switched capacitor branches can be set to other values, as long as the set of capacitor voltage ranges of the first and second switched capacitor branches covers the target supply voltage range, and the capacitor voltage ranges of each switched capacitor branch do not overlap.

[0032] According to an embodiment of this disclosure, the output switched capacitor unit includes M switched capacitor branches, where M > 2. The sum of the capacitor voltage ranges of each switched capacitor branch covers the target supply voltage range for the load. For example, if the target supply voltage range for the load is 0 to N volts, where N > 0, the size of the capacitor voltage range for each switched capacitor branch can be set to N / M volts, and the capacitor voltage ranges of each switched capacitor branch do not overlap.

[0033] According to an embodiment of this disclosure, the power stage circuit includes a feedback control unit configured to detect the real-time voltage across the load and control the power stage circuit and the output switched capacitor unit based on the real-time voltage to adjust the supply voltage of the load.

[0034] In another aspect, this disclosure also provides a method for improving the voltage conversion speed of the aforementioned DC-DC converter, combined with... Figure 5 and Figure 2 As shown, the method includes the following steps:

[0035] S1: When the load is in steady state, the capacitor in any of the switched capacitor branches of the output switched capacitor unit is connected to the two output terminals of the power stage circuit through the switch being turned on, and the switches in the other switched capacitor branches are turned off to keep the capacitor in a floating state, and the voltage on the capacitor is kept within the corresponding capacitor voltage range.

[0036] S2: When a change in load operating state requires voltage conversion, one switched capacitor branch is selected based on the capacitor voltage range of the target voltage, while the switches of all other switched capacitor branches are opened, causing the capacitors to float; and

[0037] S3: The power stage circuit and output switched capacitor unit are controlled by the feedback control unit to adjust the supply voltage of the load to the target value.

[0038] Specifically, in steady state, any one capacitor in the output capacitor array is connected to the output voltage node via a switch. The remaining capacitors are switched off, remaining floating, with their voltages constant and within their corresponding sub-range voltage intervals. When voltage conversion is required, the corresponding output capacitor is switched on based on the sub-range of the target voltage, short-circuiting it to the output voltage node. All other capacitors are switched off, floating, with their voltages remaining at the state before the switches were turned off, and within their corresponding sub-range voltage intervals. The selected output capacitor voltage is adjusted to the target output voltage value through a feedback loop. This target value is within the operating voltage range of the capacitor.

[0039] After employing the method of the present invention to improve voltage conversion speed, the voltage conversion time is the sum of the times of steps S2 and S3. Since the time required for S2 is almost zero, the voltage conversion time is equal to the time of process S3.

[0040] (2);

[0041] Where C OUT This is the capacitance value. For the selected switched capacitor branch, I represents the capacitor voltage range. CH To determine the average charging current of the capacitor, comparing formulas (1) and (2), it can be seen that, due to Less than Therefore, the voltage conversion time is significantly reduced, while the output voltage ripple and transient response remain unchanged, without the need to change the power stage circuit.

[0042] Figure 5 This is a schematic diagram of the voltage conversion waveforms for two switched capacitor branches. At this point, the voltage between the edges of the respective capacitor voltage ranges for each of the two switched capacitor branches is V. O,switch , with V O,switch The circuit is divided into two sub-ranges, high and low, with the capacitances in the two switched capacitor branches being C, respectively.OUT1 and C OUT2 The capacitances are C OUT1 and C OUT2 The voltages on are respectively V CAP1 and V CAP2 These voltages fall within two sub-voltage ranges, one high and one low. During voltage conversion, the corresponding switched capacitor branch is first selected based on the target voltage range. If the selected capacitor changes, the output voltage will initially experience a sudden change. Next, the feedback loop adjusts the output voltage, bringing the voltage range of the selected switched capacitor branch to the target value. For unselected capacitors, their voltage remains at the level of the last time the switch was turned off; the capacitor floats until it is selected again, at which point the voltage will be adjusted by the feedback loop.

[0043] This invention divides the load's supply voltage (or the converter's output voltage) into several smaller sub-ranges. During voltage conversion, it first selects the corresponding switched capacitor branch based on the sub-range containing the target output voltage to complete coarse adjustment, and then fine-tunes the capacitor voltage to the target output voltage. Since the first step of coarse adjustment consumes almost no time and significantly reduces the charge / discharge required for the output capacitor in the second step of fine adjustment, the voltage conversion time is significantly shortened. This invention can be applied to all DC-DC converters, including switching converters and linear converters, as well as boost, buck, and buck-boost converters. It has a wide range of applications and is scalable. This invention addresses the problem of DC-DC converter output voltage conversion being limited by the output capacitor's charge / discharge time. Through a two-step segmented output voltage conversion scheme of coarse adjustment followed by fine adjustment, it reduces the voltage change required by the output capacitor, thereby shortening the output capacitor's charge / discharge time and improving the converter's voltage conversion speed.

[0044] The embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. It should be noted that implementations not illustrated or described in the drawings or the main text of the specification are forms known to those skilled in the art and have not been described in detail. It should be understood that the above are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A DC-DC converter for improving voltage conversion speed, characterized in that, include: The power supply provides the input voltage as an energy source. A power stage circuit, with two input terminals connected to the power supply and two output terminals connected to the two ends of the load, is configured to transfer energy provided by the power supply to the load and to convert and adjust the supply voltage of the load by the input voltage; and An output switched capacitor unit is connected between the two output terminals of the power stage circuit. The output switched capacitor unit includes multiple switched capacitor branches arranged in parallel. Each switched capacitor branch is configured with a different capacitor voltage range, so that when the load operating state changes, the switched capacitor branch can be selected according to the capacitor voltage range corresponding to each switched capacitor branch, thereby changing the load supply voltage more quickly and stably.

2. The DC-DC converter according to claim 1, characterized in that, Each switched capacitor branch includes a capacitor and a switch connected in series between the two output terminals of the power stage circuit.

3. The DC-DC converter according to claim 2, characterized in that, The capacitor voltage ranges corresponding to each switched capacitor branch are different and do not overlap.

4. The DC-DC converter according to claim 2, characterized in that, When the load operating state changes, one of the multiple switched capacitor branches is selected based on the capacitor voltage range corresponding to each switched capacitor branch, while the remaining switched capacitor branches are disconnected and the capacitor remains in a floating state.

5. The DC-DC converter according to claim 1, characterized in that, The sum of the capacitor voltage ranges corresponding to all switched capacitor branches covers the target supply voltage range for the load.

6. The DC-DC converter according to claim 1, characterized in that, When the operating state of the load changes, the converter power stage circuit charges and discharges the capacitors in the selected switched capacitor branch while providing the current required by the load.

7. The DC-DC converter according to claim 3, characterized in that, The output switched capacitor unit includes two switched capacitor branches, namely the first switched capacitor branch and the second switched capacitor branch. The sum of the capacitor voltage range of the first switched capacitor branch and the capacitor voltage range of the second switched capacitor branch covers the target supply voltage range of the load.

8. The DC-DC converter according to claim 3, characterized in that, The output switched capacitor unit includes M switched capacitor branches, where M > 2. The sum of the capacitor voltage ranges of each switched capacitor branch covers the target supply voltage range for the load.

9. The DC-DC converter according to claim 1, characterized in that, The power stage circuit includes a feedback control unit configured to detect the real-time voltage across the load and control the power stage circuit and the output switched capacitor unit based on the real-time voltage to adjust the supply voltage of the load.

10. A method for improving the voltage conversion speed of a DC-DC converter according to any one of claims 1-9, comprising: S1: When the load is in steady state, the capacitor in any of the switched capacitor branches of the output switched capacitor unit is connected to the two output terminals of the power stage circuit through the switch being turned on, and the switches in the other switched capacitor branches are turned off to keep the capacitor in a floating state, and the voltage on the capacitor is kept within the corresponding capacitor voltage range. S2: When a change in load operating state requires voltage conversion, one switched capacitor branch is selected based on the capacitor voltage range of the target voltage, while the switches of all other switched capacitor branches are opened, causing the capacitors to float; and S3: The power stage circuit and the output switched capacitor unit are controlled by the feedback control unit to adjust the supply voltage of the load to the target value.

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