Energy distribution method for single-inductor multi-output DC-DC converter

Abstract

The present disclosure provides an energy distribution method for a single-inductor multi-output DC-DC converter. The method comprises: controlling, by an inductive energy generation architecture, an inductor to extract energy from an input unit, and obtaining an inductive current; controlling the switch groups on the output side to output, according to an initial setting rule, the inductive current one by one along a plurality of output branches; detecting in real time a step response state of each output branch; and on the basis of the step response state, adjusting the initial setting rule to better complete the distribution of the inductive current so as to reduce the crossover regulation among output channels under the load jump.

Description

Energy allocation method for single-inductor multiple-output DC-DC converter Technical Field

[0001] The present disclosure relates to the technical field of electronic equipment, and in particular to an energy distribution method for a single-inductor multiple-output DC-DC converter. Background Art

[0002] Ultra-compact size and low bill of materials (BOM) provide a highly suitable solution for space-constrained wearables, headsets, IoT devices, and other small, battery-powered consumer electronics. Using a single inductor in a power management chip to provide multiple output voltages is a promising solution. However, using a single inductor increases circuit control complexity. In addition to controlling the energy transferred by the inductor, the distribution of that energy to each output must also be controlled. The power stage of a multi-output converter can be divided into two parts: energy generation and energy distribution. When the total load is high, the inductor needs to supply a very high current. In this case, operating the inductor in a continuous conduction state can achieve higher efficiency. However, if the inductor is continuously on, it is impossible for all output-side energy distribution switches to be completely off. If all are off, the inductor current cannot continue to flow, resulting in extremely high voltages on the inductor side, which could break down the switches. Therefore, the distribution between each output must be closely linked. Under severe transients, the duty cycle of each output can change dramatically, leading to significant cross-regulation between the outputs. Especially under high load currents, even small changes in duty cycle can cause significant output voltage fluctuations. Existing control methods are unable to accurately modulate the energy of each output under drastic duty cycle changes.

[0003] Summary of the Invention

[0004] The present disclosure provides an energy distribution method for a single-inductor multiple-output DC-DC converter, comprising: controlling an inductor to extract energy from an input unit through an inductor energy generation architecture to obtain an inductor current; controlling an output-side switch group to output the inductor current one by one along multiple output branches according to an initial set rule; detecting the step response state of each output branch in real time; and adjusting the initial set rule based on the step response state to better distribute the inductor current and reduce cross-adjustment between output channels under load jumps.

[0005] Optionally, the initial setting rule includes outputting the inductor currents one by one along the plurality of output branches in sequence within a setting period.

[0006] Optionally, the initial setting rule further includes outputting the inductor currents one by one along the multiple output branches in a fixed order within a set period.

[0007] Optionally, when it is detected that the step response of a load of a certain output branch is abnormal, the energy distribution order of the output branch is adjusted.

[0008] Optionally, the step response state is determined by detecting the degree of change of the output voltage of each output branch.

[0009] Optionally, when it is detected that the fluctuation of the output voltage of the output branch reaches or exceeds the steady-state ripple, it is determined that the load step response of the output branch is abnormal.

[0010] Optionally, adjusting the initial setting rule according to the step response state includes: when it is determined that the step response state is abnormal, changing the inductor current output sequence in the initial setting rule.

[0011] Optionally, adjusting the initial setting rules according to the step response state includes: when it is determined that the step response state is abnormal, changing the inductor current output order in the initial setting rules, skipping or compressing the output time of the output branch with the abnormal step response state, and adjusting the output to the output branch with the next priority in the initial setting rules.

[0012] Optionally, adjusting the initial setting rule according to the step response state further includes: after other output branches complete outputting the inductor current, continuing to adjust to the output branch with the abnormal step response state to output during the remaining time within the set period. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG1 is a schematic diagram showing the circuit structure of a single inductor multiple output (SIMO) DC-DC converter.

[0014] FIG2 is a flow chart of an energy distribution method for a SIMO DC-DC converter according to an embodiment of the present disclosure.

[0015] FIG3 is a schematic diagram of an energy distribution method of a traditional SIMO DC-DC converter.

[0016] FIG4 is a schematic diagram showing energy output results of a conventional single-inductor three-way output DC-DC converter.

[0017] FIG5 is a schematic diagram of an energy distribution method for a SIMO DC-DC converter according to an embodiment of the present disclosure.

[0018] FIG6 is a schematic diagram showing energy output results of a single-inductor three-output DC-DC converter according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0019] This disclosure provides an energy distribution method for a single-inductor, multiple-output (SIMO) DC-DC converter. When a load transient occurs, the proposed control method adjusts the energy distribution order, shifting the channel experiencing the transient to the end of the energy distribution order, prioritizing charge supply to channels without transients. This provides a control strategy for variable-order energy distribution, effectively reducing cross-adjustments between channels.

[0020] As shown in Figure 1, in a single inductor multiple output (SIMO) DC-DC converter, the inductor current I L The switch S is controlled by the control circuit P and S N The linkage controls the inductance from the input unit V IN The inductor current I L Through the output branches (N1, N2, ... N i ) in the switches (S1, S2, ...S i ) are distributed to each output branch in a fixed order, and the output capacitors (C1, C2, ... C i ) to charge and provide output voltage (V1, V2, ...V i 1 and 3, for example, switch S1 is closed, and the other switches are opened, and the inductor current flows to the output branch corresponding to switch S1; then, switch S2 is closed, and the other switches are opened, and the inductor current flows to the output branch corresponding to switch S2; in accordance with the pre-set sequence, until switch S i Closed, other switches are open, and the inductor current flows to switch S i After one set cycle ends, it enters the next set cycle and repeats continuously.

[0021] Figures 1 and 4 illustrate an example of a single inductor with three output branches. It can be observed that, due to its high priority, the first output branch N1 can effectively complete energy distribution, with no jitter in the output voltage V1. However, the load current of the second output branch N2 experiences a 2A jump every 100ns. Since the energy allocation priority of the second output branch N2 is higher than that of the third output branch N3, the energy allocation of the second output branch N2 can occupy most of a set cycle, or even the entire cycle. This results in the third output branch N3, which has a lower energy allocation priority, having no time to distribute energy. The fast step response of the second output branch N2 causes the energy allocation to occupy the remaining time, completely occupying the time allocated to the third output branch N3 in the initial setting rule. As a result, the output voltage V3 of the third output branch N3 fluctuates significantly due to the crosstalk between the output branches, causing it to drop. Therefore, in current SIMO designs with sequential energy allocation, the energy requirements of the lower-priority channels must be accurately predicted in advance; otherwise, crosstalk adjustment issues cannot be avoided. This precise prediction requires significant digital circuit computing power or extremely precise analog circuit design.

[0022] Therefore, the present disclosure proposes a variable-order energy distribution method for SIMO converters, which can greatly alleviate cross-regulation under large load jumps.

[0023] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0024] In an embodiment of the present disclosure, a method for distributing energy in a single-inductor multiple-output DC-DC converter is provided. Referring to FIG. 2 and FIG. 1 , the method includes:

[0025] Operation S1: Control the inductor L by the input unit V through the inductor energy generation architecture IN Extract energy and obtain the inductor current I L ;

[0026] Operation S2: By controlling the switch group (S1, S2, ... S i ) outputting the inductor currents one by one along the plurality of output branches according to an initially set rule;

[0027] Operation S3: detecting the step response state of each output branch in real time; and

[0028] Operation S4: adjusting the initial setting rule according to the step response state to better distribute the inductor current and reduce cross-adjustment between output channels under load jump.

[0029] Optionally, the inductive energy generation architecture is selected from a Buck architecture, a Buck-boost architecture, or a Boost architecture. For example, FIG1 shows a Buck architecture, which includes a first switch disposed between the input unit and the inductor and a second switch disposed between the inductor and ground. It should be noted that the inductive energy generation architecture may also be another architecture capable of inductive energy generation besides the Buck architecture, the Buck-boost architecture, or the Boost architecture, and the present disclosure is not limited thereto.

[0030] According to an embodiment of the present disclosure, the inductive energy generation architecture and the switch group operate under the control of a control command signal issued by a control circuit.

[0031] According to the embodiment of the present disclosure, the initial setting rule includes sequentially following multiple output branches (N1, N2, ... N i ) output inductor current one by one; for example, along the output branches N1, N2, ... N i-1 、N i Output inductor current I L .

[0032] According to an embodiment of the present disclosure, the initial setting rule further includes outputting the inductor current one by one along the multiple output branches in a fixed order within a set period. For example, energy is first distributed along the first output branch and the third output branch, and then along the second output branch and the fourth output branch.

[0033] After the above energy distribution, the output capacitors (C1, C2, ...C i ) for charging. As shown in Figure 1, each output branch can be connected to a corresponding load. For example, the load can be each core chip in the central processing unit (CPU). When the load is working, each output capacitor provides an output voltage (V1, V2, ... V i ).

[0034] According to an embodiment of the present disclosure, detecting the step response state of each output branch in real time includes determining the step response state by detecting the degree of change of the output voltage of each output branch.

[0035] According to an embodiment of the present disclosure, when it is detected that the fluctuation of the output voltage of the output branch reaches or exceeds the steady-state ripple, it is determined that the load step response of the output branch is abnormal.

[0036] According to an embodiment of the present disclosure, when the fluctuation of the output voltage of the detected output branch reaches or exceeds twice the ripple in the steady state, it is determined that the step response of the output branch is abnormal.

[0037] According to an embodiment of the present disclosure, when the fluctuation of the output voltage of the detected output branch reaches or exceeds 1 times the ripple in the steady state, it is determined that the step response of the output branch is abnormal.

[0038] According to an embodiment of the present disclosure, adjusting the initial setting rule according to the step response state includes: when it is determined that the step response state is abnormal, changing the output order of the inductor current in each output branch in the initial setting rule.

[0039] According to an embodiment of the present disclosure, adjusting the initial setting rules according to the step response state includes: when it is determined that the step response state is abnormal, changing the output order of the inductor current in each output branch in the initial setting rules, skipping or compressing the output time of the output branch with the abnormal step response state, and adjusting the output to the output branch with the next priority in the initial setting rules.

[0040] According to an embodiment of the present disclosure, adjusting the initial setting rule according to the step response state also includes: after other output branches complete the output of the inductor current, continuing to adjust to the output branch with the previous abnormal step response state for output during the remaining time within the set period.

[0041] This disclosure proposes a variable order energy distribution strategy for SIMO converter. This energy distribution strategy can greatly alleviate the cross adjustment under large load jump. In a fixed period, all output branches (N1~N i ) After the allocation is completed, if there is still time left, the output branch where the transient occurs will be reallocated within the cycle, or reallocated within multiple cycles. As shown in Figure 5, taking the transient occurrence of one channel as an example, the allocation strategy is given. Within a fixed cycle, after all output branches are allocated, if there is still time left, it will be allocated to the output node N of the output branch where the transient occurs. k, where k is one of 1 to i. In the stable state, the converter allocates energy to each pair of output branches for charging in the order of the initial setting rules by default. When a transient occurs, the converter can automatically change the energy distribution order according to the distribution strategy. The converter will first suppress the charging time of the output where the transient occurs, thereby ensuring that the output with lower priority has enough time to complete the charge control. The remaining time will then be reallocated to the output where the transient occurs to ensure that the transient response performance is not affected. This is different from the previous sequential energy distribution method, which always gives priority to satisfying the output where the transient occurs regardless of whether there are other outputs that need energy later, resulting in the inability to satisfy the output with low priority (or low priority). The present disclosure places all outputs that may be affected at a higher priority and completes the charge distribution within a fixed period, thereby greatly alleviating cross-regulation. Figure 6 also shows an example of a single-inductor three-output branch. The test conditions are exactly the same as those in Figure 4. The load current corresponding to the second output branch N2 jumps by 2A every 100ns, causing the voltage fluctuation of the second output branch N2 to reach or exceed the steady-state ripple, thereby determining that the output branch step response is abnormal. Therefore, the energy distribution to the second output branch N2 is immediately terminated and adjusted to the third output branch N3, so that the third output branch effectively completes the energy distribution and the output voltage jitter meets the requirements; it should be noted that, according to the different configuration parameters of the devices in the actual converter or the different actual application scenarios of the converter, the output branch step response abnormality can be determined when the fluctuation of the output voltage of the output branch reaches or exceeds the steady state; or the output branch step response abnormality can be determined when the fluctuation of the output voltage of the output branch reaches or exceeds 0.1 times, or 0.2 times, or 0.5 times, or 2 times, or 3 times the steady-state ripple; or when the load of a certain output branch is about to run, the relevant control circuit will know in advance through detection that the output branch is about to have a load step abnormality, thereby adjusting the distribution order in the variable initial setting rule. By adopting the variable sequence energy distribution strategy proposed in this disclosure, it can be found by comparison that, compared with the sequential energy distribution, the cross-adjustment voltage of this scheme is reduced from nearly 200mV to a level close to the steady-state ripple.

[0042] Based on sequential energy distribution, this disclosure proposes a method for variable-order energy distribution. When a transient load jump occurs, the control method proposed in this disclosure can adjust the energy distribution order, moving the channel experiencing the transient jump to the end of the energy distribution order, prioritizing the charge supply to the channel branches without transients. Therefore, this disclosure proposes a control strategy for variable-order energy distribution, effectively reducing cross-adjustments between channels.

[0043] The specific embodiments of the present disclosure described above do not limit the scope of protection of the present disclosure. Any other corresponding changes and modifications made based on the technical concept of the present disclosure should be included in the scope of protection of the claims of the present disclosure.

Claims

1. An energy distribution method for a single-inductor multi-output DC-DC converter, comprising: Controlling an inductor to extract energy from an input unit through an inductor energy generation architecture to obtain an inductor current; Controlling a switch group on the output side to output the inductor current one by one along multiple output branches according to an initial setting rule; Real-time detecting the step response state of each output branch; And Adjusting the initial setting rule according to the step response state to better complete the distribution of the inductor current so as to reduce the cross-regulation between output channels under load jumps.

2. The energy distribution method for a single-inductor multi-output DC-DC converter according to claim 1, wherein the initial setting rule includes outputting the inductor current one by one along multiple output branches in sequence within a set period.

3. The energy distribution method for a single-inductor multi-output DC-DC converter according to claim 1, wherein the initial setting rule further includes outputting the inductor current one by one along multiple output branches in a fixed order within a set period.

4. The energy distribution method for a single-inductor multi-output DC-DC converter according to claim 1, when the step response of the load of a certain output branch is detected to be abnormal, adjusting the energy distribution order of this output branch.

5. The energy distribution method for a single-inductor multi-output DC-DC converter according to claim 4, determining the step response state by detecting the degree of change of the output voltage of each output branch.

6. The energy distribution method for a single-inductor multi-output DC-DC converter according to claim 5, when it is detected that the fluctuation of the output voltage of the output branch reaches or exceeds the ripple at steady state, determining that the step response of the load of this output branch is abnormal.

7. The method for energy distribution of the single-inductor multi-output DC-DC converter according to any one of claims 1-4, wherein adjusting the initial setting rule according to the step response state includes: When it is determined that the step response state is abnormal, changing the inductor current output order in the initial setting rule.

8. The method for energy distribution of the single-inductor multi-output DC-DC converter according to any one of claims 1-4, wherein the adjustment of the initial setting rule according to the step response state includes: When it is determined that the step response state is abnormal, changing the inductor current output order in the initial setting rule, skipping or compressing the output time of the output branch with an abnormal step response state, and adjusting to the output branch with the next priority in the initial setting rule for output.

9. The method for energy distribution of the single-inductor multi-output DC-DC converter according to claim 8, wherein the adjustment of the initial setting rule according to the step response state further includes: After the inductor current output of other output branches is completed, continue to adjust to the output branch with an abnormal step response state before within the remaining time in the set period for output.

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