Quasi-frequency conversion control circuit and method based on single-inductor dual-output switching converter

Abstract

Embodiments of the present invention disclose a quasi-variable frequency control circuit and method for a single-inductor dual-output switching converter. By combining a critical conduction mode with a discontinuous conduction mode to form a hybrid conduction mode with zero freewheeling current, this circuit decouples the different output circuits of the single-inductor dual-output switching converter and eliminates cross-influence between the two output branches. This circuit offers advantages such as no cross-influence between the different output branches, fast load transient response, a simple structure, and convenient compensator design, making the single-inductor dual-output converter more efficient and stable.

Description

Technical Field

[0001] The present invention relates to the field of power electronic equipment, and in particular to a quasi-frequency conversion control circuit and method for a single-inductor dual-output switching converter. Background Art

[0002] The Single-Inductor Multiple-Output (SIMO) switching converter uses one inductor and adopts the time-division multiplexing principle to power each output branch separately, meeting the integration requirements of portable electronic products.

[0003] Since each output branch of the SIMO switching converter has independent sampling feedback, the accuracy requirement for the voltage of each output branch is relatively high. However, since the output branches share an inductor, there is a relatively obvious cross-influence between the output branches. Summary of the Invention

[0004] Based on this, it is necessary to address the above problems and propose a quasi-frequency conversion control circuit and method based on a single-inductor dual-output switching converter, which has achieved the purpose of eliminating the more obvious cross-influence between the output branches of the single-inductor dual-output switching converter.

[0005] To achieve the above objectives, the present application provides, in a first aspect, a quasi-variable frequency control circuit based on a single-inductor dual-output switching converter, the circuit comprising: a voltage detection module, a compensation module, a current detection module, a sample-and-hold module, a proportional selector, a comparison module, a third comparator, a fourth comparator, a first AND gate, a second AND gate, a third AND gate, a fourth AND gate, a first OR gate, a second OR gate, a first trigger, a second trigger, and a third trigger;

[0006] The input end of the voltage detection module is connected to the single-inductor dual-output switching converter, and the output end of the voltage detection module is also connected to the input end of the compensation module. The output end of the compensation module is respectively connected to the input end of the first AND gate and the input end of the second AND gate through the comparison module. The output end of the first AND gate and the output end of the second AND gate are both connected to the input end of the first OR gate.

[0007] The input end of the current detection module is connected to the single-inductor dual-output switching converter, and the output end of the current detection module is respectively connected to the input end of the proportional selector, the input end of the third comparator, and the input end of the fourth comparator. The output end of the current detection module is also connected to the input end of the proportional selector through the sample and hold device, and the output end of the proportional selector is respectively connected to the input end of the third comparator and the input end of the fourth comparator;

[0008] The output end of the third comparator is connected to the input end of the third AND gate, the output end of the third AND gate is connected to the input end of the second flip-flop, and the output end of the second flip-flop is respectively connected to the input end of the first AND gate, the input end of the second AND gate, the input end of the third AND gate, the input end of the fourth AND gate, the input end of the second OR gate, and the single-inductor dual-output switching converter;

[0009] The output end of the first OR gate and the output end of the second OR gate are both connected to the input end of the first trigger, and the output end of the first trigger is respectively connected to the input end of the third trigger and the single-inductor dual-output switching converter;

[0010] The output end of the fourth comparator is connected to the input end of the fourth AND gate, the output end of the fourth AND gate is connected to the input end of the third trigger, and the output end of the third trigger is connected to the single-inductor dual-output switching converter.

[0011] Furthermore, the voltage detection module is used to detect the output voltage of the single-inductor dual-output switching converter to obtain an output voltage signal, and send the output voltage signal to the compensation module;

[0012] The compensation module is configured to obtain a compensation signal according to the output voltage signal and the voltage reference value signal, and send the compensation signal to the comparison module;

[0013] The comparison module is configured to compare the compensation signal with the sawtooth wave signal to obtain a first voltage signal and a second voltage signal, and send the first voltage signal and the second voltage signal to the first AND gate and the second AND gate respectively;

[0014] The current detection module is configured to detect the inductor current and the output current of the single-inductor dual-output switching converter, obtain an inductor current signal and an output current signal, and send the inductor current signal to the sample and hold, the third comparator, and the fourth comparator, respectively, and send the output current signal to the ratio selector;

[0015] The sample and hold device is used to sample the inductor current signal I at each clock signal point. L Sampling is performed and held until the end of the current clock cycle to obtain the target inductor current signal i L0 and the target inductor current signal i L0 Send to the ratio selector;

[0016] the proportional selector is configured to obtain a target current signal according to the target inductor current signal and the output current signal, and send the target current signal to the third comparator and the fourth comparator respectively;

[0017] the third comparator is configured to obtain a third voltage signal by comparing the inductor current signal with the target current signal, and send the third voltage signal to the third AND gate;

[0018] The third AND gate is configured to obtain a third trigger signal according to the third voltage signal and the first control signal, and send the third trigger signal to the second trigger;

[0019] the second flip-flop being configured to obtain a first control signal and a second control signal based on the clock signal and the third trigger signal, and to send the first control signal and the second control signal to the single-inductor dual-output switching converter to control branch switches of the single-inductor dual-output switching converter, and to send the first control signal to the first AND gate and the third AND gate, respectively, and to send the second control signal to the first AND gate, the second AND gate, the second OR gate, and the fourth AND gate;

[0020] The first AND gate is configured to obtain a first comparison signal according to the first output voltage signal and the first control signal, and send the first comparison signal to the first OR gate;

[0021] The second AND gate is configured to obtain a second comparison signal according to the second output voltage signal and the second control signal, and send the second comparison signal to the first OR gate;

[0022] The first OR gate is configured to obtain a first trigger signal according to the first comparison signal and the second comparison signal; and send the first trigger signal to the first trigger;

[0023] the second OR gate is configured to obtain a first selection signal according to the clock signal and the second control signal, and send the first selection signal to the first flip-flop;

[0024] the first trigger being configured to obtain a third control signal for the main switch according to the first trigger signal and the first selection signal, and to send the third control signal to the single-inductor dual-output switching converter to control the main switch of the single-inductor dual-output switching converter, and further to send the third control signal to the third trigger;

[0025] the fourth comparator is configured to obtain a fourth voltage signal by comparing the inductor current signal with the target current signal, and send the fourth voltage signal to the fourth AND gate;

[0026] The fourth AND gate is configured to obtain a third selection signal according to the fourth voltage signal and the second control signal, and send the third selection signal to the third trigger;

[0027] The third trigger is used to obtain a fourth control signal based on the third control signal and the third selection signal, and send the fourth control signal to the single-inductor dual-output switching converter to control the freewheeling switch tube of the single-inductor dual-output switching converter.

[0028] Furthermore, the second trigger is used to obtain the first control signal and the second control signal according to the clock signal and the third trigger signal, and also includes: when the second trigger only receives the clock signal, the control signal obtained at this time is the first control signal.

[0029] Furthermore, the voltage detection module includes a first voltage detection circuit and a second voltage detection circuit;

[0030] The input end of the first voltage detection circuit is connected to the output end of the single-inductor dual-output switching converter, and the output end of the first voltage detection circuit is connected to the compensation module;

[0031] An input end of the second voltage detection circuit is connected to an output end of the single-inductor dual-output switching converter, and an output end of the second voltage detection circuit is connected to the compensation module.

[0032] Furthermore, the compensation module includes a first compensator and a second compensator;

[0033] Wherein, the input end of the first compensator is connected to the first voltage detection circuit, and the output end of the first compensator is connected to the comparison module;

[0034] An input terminal of the second compensator is connected to the second voltage detection circuit, and an output terminal of the second compensator is connected to the comparison module.

[0035] Furthermore, the comparison module includes a first comparator and a second comparator;

[0036] Wherein, the input end of the first comparator is connected to the first compensator, and the output end of the first comparator is connected to the first AND gate;

[0037] An input terminal of the second comparator is connected to the second compensator, and an output terminal of the second comparator is connected to the second AND gate.

[0038] Furthermore, the current detection module includes a first current detection circuit, a second current detection circuit and a third current detection circuit;

[0039] The input end of the first current detection circuit is connected to the single-inductor dual-output switching converter, and the output end of the first current detection circuit is connected to the sample and hold, the third comparator, and the fourth comparator respectively;

[0040] An input end of the second current detection circuit is connected to the single-inductor dual-output switching converter, and an output end of the second current detection circuit is connected to the proportional selector;

[0041] An input end of the third current detection circuit is connected to the single-inductor dual-output switching converter, and an output end of the third current detection circuit is connected to the proportional selector.

[0042] To achieve the above-mentioned object, the second aspect of the present application provides a quasi-variable frequency control method based on a single-inductor dual-output switching converter, the method being applied to the circuit described in the first aspect, the method comprising:

[0043] a voltage detection module detecting an output voltage of the single-inductor dual-output switching converter to obtain an output voltage signal, and sending the output voltage signal to a compensation module; the compensation module obtaining a compensation signal based on the output voltage signal and a voltage reference value signal, and sending the compensation signal to a comparison module; the comparison module comparing the compensation signal with a sawtooth wave signal to obtain a first voltage signal and a second voltage signal, and sending the first voltage signal and the second voltage signal to a first AND gate and a second AND gate, respectively;

[0044] The current detection module detects the inductor current and the output current of the single-inductor dual-output switching converter to obtain an inductor current signal and an output current signal, and sends the inductor current signal to the sample and hold, the third comparator, and the fourth comparator respectively, and sends the output current signal to the ratio selector;

[0045] The sample-and-hold device samples the inductor current signal at each clock signal point and holds the sample until the end of the current clock cycle to obtain a target inductor current signal, and sends the target inductor current signal to the ratio selector;

[0046] The proportional selector obtains a target current signal according to the target inductor current signal and the output current signal, and sends the target current signal to the third comparator and the fourth comparator respectively;

[0047] The third comparator compares the inductor current signal with the target current signal to obtain a third voltage signal, and sends the third voltage signal to a third AND gate;

[0048] The third AND gate obtains a third trigger signal according to the third voltage signal and the first control signal, and sends the third trigger signal to the second trigger;

[0049] The second flip-flop obtains a first control signal and a second control signal according to the third trigger signal and the clock signal, and sends the first control signal and the second control signal to the single-inductor dual-output switching converter to control the branch switches of the single-inductor dual-output switching converter. The second flip-flop also sends the first control signal to the first AND gate and the third AND gate respectively, and sends the second control signal to the first AND gate, the second OR gate, and the fourth AND gate.

[0050] The first AND gate obtains a first comparison signal according to the first voltage signal and the first control signal, and sends the first comparison signal to the first OR gate;

[0051] The second AND gate obtains a second comparison signal according to the second voltage signal and the second control signal, and sends the second comparison signal to the first OR gate;

[0052] The first OR gate obtains a first trigger signal according to the first comparison signal and the second comparison signal; and sends the first trigger signal to the first trigger;

[0053] The second OR gate obtains a first selection signal according to the clock signal and the second control signal, and sends the first selection signal to the first flip-flop;

[0054] The first trigger obtains a third control signal for the main switch according to the first trigger signal and the first selection signal, sends the third control signal to the single-inductor dual-output switching converter to control the main switch of the single-inductor dual-output switching converter, and further sends the third control signal to a third trigger;

[0055] The fourth comparator compares the inductor current signal with the target current signal to obtain a fourth voltage signal, and sends the fourth voltage signal to the fourth AND gate;

[0056] The fourth AND gate obtains a third selection signal according to the fourth voltage signal and the second control signal, and sends the third selection signal to the third trigger;

[0057] The third trigger obtains a fourth control signal according to the third control signal and the third selection signal, and sends the fourth control signal to the single-inductor dual-output switching converter to control the freewheeling switch tube of the single-inductor dual-output switching converter.

[0058] Furthermore, the voltage detection module detects the output voltage of the single-inductor dual-output switching converter to obtain an output voltage signal, and sends the output voltage signal to the compensation module; the compensation module obtains a compensation signal based on the output voltage signal and a voltage reference value signal, and sends the compensation signal to the comparison module; the comparison module compares the compensation signal with the sawtooth wave signal to obtain a first voltage signal and a second voltage signal, and sends the first voltage signal and the second voltage signal to a first AND gate and a second AND gate, respectively, specifically including:

[0059] The first voltage detection circuit in the voltage detection module detects the first output voltage of the single-inductor dual-output switching converter to obtain a first output voltage signal, and sends the first output voltage signal to the compensation module;

[0060] The second voltage detection circuit in the voltage detection module detects the second output voltage of the single-inductor dual-output switching converter to obtain a second output voltage signal, and sends the second output voltage signal to the compensation module;

[0061] The first compensator in the compensation module obtains a first compensation signal according to the first output voltage signal and the voltage reference value signal, and sends the first compensation signal to the comparison module;

[0062] The second compensator in the compensation module obtains a second compensation signal according to the second output voltage signal and the voltage reference value signal, and sends the second compensation signal to the comparison module;

[0063] The first comparator in the comparison module obtains a first voltage signal according to the first compensation signal and the sawtooth wave signal, and sends the first voltage signal to the first AND gate;

[0064] The second comparator in the comparison module obtains a second voltage signal according to the second compensation signal and the sawtooth wave signal, and sends the second voltage signal to the second AND gate.

[0065] Furthermore, the current detection module detects the inductor current and the output current of the single-inductor dual-output switching converter to obtain an inductor current signal and an output current signal, and sends the inductor current signal to the sample-and-hold, the third comparator, and the fourth comparator, respectively, and sends the output current signal to the ratio selector, specifically including:

[0066] The first current detection circuit in the current detection module detects the inductor current of the single-inductor dual-output switching converter to obtain the inductor current signal, and sends the inductor current signal to the sample and hold, the third comparator, and the fourth comparator respectively;

[0067] The second current detection circuit in the current detection module detects the first output current of the single-inductor dual-output switching converter to obtain the first output current signal, and sends the first output current signal to the proportional selector;

[0068] The third current detection circuit in the current detection module detects the second output current of the single-inductor dual-output switching converter, obtains the second output current signal, and sends the second output current signal to the proportional selector.

[0069] The embodiments of the present invention have the following beneficial effects:

[0070] The present invention connects a single-inductor dual-output switch to a compensation module through a converter voltage detection module, the compensation module is respectively connected to a first AND gate and a second AND gate through a comparison module, and the first AND gate and the second AND gate are both connected to a first OR gate; the single-inductor dual-output switch converter is respectively connected to a proportional selector, a third comparator, and a fourth comparator through a current detection module, the current detection module is further connected to the proportional selector through a sample and hold, and the proportional selector is respectively connected to the third comparator and the fourth comparator; the third comparator is connected to a second trigger through a third AND gate, and the second trigger is respectively connected to the first AND gate, the second AND gate, the third AND gate, the fourth AND gate, the second OR gate, and the fourth comparator. and a single-inductor dual-output switching converter; the first OR gate and the second OR gate are both connected to the first trigger, and the first trigger is respectively connected to the third trigger and the single-inductor dual-output switching converter; the fourth comparator is connected to the third trigger via a fourth AND gate, and the third trigger is connected to the single-inductor dual-output switching converter. The above circuit is used to control the output branch of the single-inductor dual-output switching converter to have an inductor current follow-through value of zero during operation, but without a duration, so as to achieve a combination of a critical conduction mode and a discontinuous conduction mode. At this time, no matter how the load changes, the energy is always in a balanced state, thereby achieving the purpose of eliminating the cross-influence between different output branches. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0072] in:

[0073] Figure 1 Schematic diagram of a quasi-variable frequency control circuit based on a single-inductor dual-output switching converter according to an embodiment of the present application;

[0074] Figure 2In the embodiment of this application Figure 1 Detailed circuit diagram of the quasi-frequency control circuit;

[0075] Figure 3 This is the load jump diagram of output branch a under the traditional control method;

[0076] Figure 4 This is the load jump diagram of output branch b under the traditional control method;

[0077] Figure 5 This is a load jump diagram of the output branch a under the quasi-variable frequency control method proposed in an embodiment of the present application;

[0078] Figure 6 This is a load jump diagram of the output branch b under the quasi-variable frequency control method proposed in an embodiment of the present application;

[0079] Figure 7a and Figure 7b A comparison diagram of the cross-effect effect of output branches under the quasi-variable frequency control method proposed in an embodiment of the present application;

[0080] Figure 8a and Figure 8b This is a comparison diagram of the voltage overshoot effect under the quasi-frequency conversion control method proposed in an embodiment of the present application. DETAILED DESCRIPTION

[0081] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0082] In the embodiment of the present application, a quasi-variable frequency control circuit based on a single-inductor dual-output switching converter is provided. Figure 1 , Figure 1 Schematic diagram of a quasi-variable frequency control circuit based on a single-inductor dual-output switching converter according to an embodiment of the present application. Figure 1 TD can be expressed as a single-inductor dual-output switching converter.

[0083] The quasi-variable frequency control circuit based on the single-inductor dual-output switching converter proposed in the embodiment of the present application includes: a voltage detection module 103, a compensation module 104, a current detection module 102, a sample-and-hold SH, a proportional selector KK, a comparison module 105, a third comparator COMP3, a fourth comparator COMP4, a first AND gate AND1, a second AND gate AND2, a third AND gate AND3, a fourth AND gate AND4, a first OR gate OR1, a second OR gate OR2, a first flip-flop RS1, a second flip-flop RS2, and a third flip-flop RS3;

[0084] Specifically, the connection relationship between the quasi-frequency conversion control circuit includes: the input end of the voltage detection module 103 is connected to the single-inductor dual-output switching converter TD, and the output end of the voltage detection module 103 is also connected to the input end of the compensation module 104. The output end of the compensation module 104 is connected to the input end of the first AND gate AND1 and the input end of the second AND gate AND2 through the comparison module 105, respectively. The output end of the first AND gate AND1 and the output end of the second AND gate AND2 are both connected to the input end of the first OR gate OR1.

[0085] The input end of the current detection module 102 is connected to the single-inductor dual-output switching converter TD, and the output end of the current detection module 102 is respectively connected to the input end of the proportional selector KK, the input end of the third comparator COMP3, and the input end of the fourth comparator COMP4. The output end of the current detection module 102 is also connected to the input end of the proportional selector KK through the sample-and-hold SH. The output end of the proportional selector KK is respectively connected to the input end of the third comparator COMP3 and the input end of the fourth comparator COMP4.

[0086] An output terminal of the third comparator COMP3 is connected to an input terminal of a third AND gate AND3, an output terminal of the third AND gate AND3 is connected to an input terminal of a second flip-flop RS2, an output terminal of the second flip-flop RS2 is connected to an input terminal of the first AND gate AND1, an input terminal of the second AND gate AND2, an input terminal of the third AND gate AND3, an input terminal of the fourth AND gate AND4, an input terminal of the second OR gate OR2, and the single-inductor dual-output switching converter TD, respectively;

[0087] The output end of the first OR gate OR1 and the output end of the second OR gate OR2 are both connected to the input end of the first flip-flop RS1, and the output end of the first flip-flop RS1 is respectively connected to the input end of the third flip-flop RS3 and the single-inductor dual-output switching converter TD;

[0088] The output of the fourth comparator COMP4 is connected to the input of the fourth AND gate AND4. The output of the fourth AND gate AND4 is connected to the input of the third flip-flop RS3. The output of the third flip-flop RS3 is connected to the single-inductor dual-output switching converter TD.

[0089] It is important to note here that Figure 1 The connection relationship between the quasi-frequency conversion circuits in the Figure 1 The figure shows the connection relationship between the output end of the current detection module 102 and the input end of the fourth comparator COMP4, the output end of the second trigger RS2 and the input end of the second AND gate AND2, the output end of the second trigger RS2 and the input end of the fourth AND gate AND4, and the output end of the second trigger RS2 and the single-inductor dual-output switching converter TD.

[0090] In the embodiment of the present application, the present invention uses the above-mentioned quasi-frequency conversion control circuit to control the output branch of the single-inductor dual-output switching converter to have an inductor current follow-on value of zero during operation, but without a duration, so as to achieve a combination of a critical conduction mode and a discontinuous conduction mode. At this time, no matter how the load changes, the energy is always in a balanced state, thereby achieving the purpose of eliminating the cross-influence between different output branches.

[0091] For easier understanding, please refer to Figure 2 , Figure 2 In the embodiment of this application Figure 1 The detailed circuit diagram of the quasi-frequency control circuit, and Figure 2 Included Figure 1 The voltage detection module 103, the compensation module 104, the current detection module 102, the sample and hold SH, the proportional selector KK, the comparison module 105, the third comparator COMP3, the fourth comparator COMP4, the first AND gate AND1, the second AND gate AND2, the third AND gate AND3, the fourth AND gate AND4, the first OR gate OR1, the second OR gate OR2, the first trigger RS1, the second trigger RS2 and the third trigger RS3, so we will not go into too much detail about each module here.

[0092] The power supply control circuit of the embodiment of the present application performs quasi-frequency conversion control on the input main circuit and two output branches of a single-inductor dual-output switching converter.

[0093] In the embodiment of the present application, the voltage detection module 103 includes a first voltage detection circuit VS1 and a second voltage detection circuit VS2; the compensation module 104 includes a first compensator EA1 and a second compensator EA2; the comparison module 105 includes a first comparator COMP1 and a second comparator COMP2; and the current detection module 102 includes a first current detection circuit IS1, a second current detection circuit IS2 and a third current detection circuit IS3.

[0094] Specifically, the input end of the first voltage detection circuit VS1 is connected to the output end of the single-inductor dual-output switching converter TD, and the output end of the first voltage detection circuit VS1 is connected to the input end of the first compensator EA1, the output end of the first comparator EA1 is connected to the input end of the first comparator COMP1, and the output end of the first comparator COMP1 is connected to the input end of the first AND gate AND1; the input end of the second voltage detection circuit VS2 is connected to the output end of the single-inductor dual-output switching converter TD, and the output end of the second voltage detection circuit VS2 is connected to the input end of the second compensator EA2, the output end of the second comparator EA2 is connected to the input end of the second comparator COMP2, and the output end of the second comparator COMP2 is connected to the input end of the second AND gate AND2; the output end of the first AND gate AND1 and the output end of the second AND gate AND2 are both connected to the input end of the first OR gate OR1.

[0095] An input end of the first current detection circuit IS1 is connected to the single-inductor dual-output switching converter TD, and an output end of the first current detection circuit IS1 is respectively connected to the sample-and-hold SH, the third comparator COMP3, and the fourth comparator COMP4; an input end of the second current detection circuit IS2 is connected to the single-inductor dual-output switching converter TD, and an output end of the second current detection circuit IS2 is connected to an input end of a proportional selector KK; an input end of the third current detection circuit IS3 is connected to the single-inductor dual-output switching converter TD, and an output end of the third current detection circuit IS3 is connected to an input end of the proportional selector KK, and an output end of the proportional selector KK is respectively connected to an input end of the third comparator COMP3 and an input end of the fourth comparator COMP4;

[0096] An output terminal of the third comparator COMP3 is connected to an input terminal of a third AND gate AND3, an output terminal of the third AND gate AND3 is connected to an input terminal of a second flip-flop RS2, an output terminal of the second flip-flop RS2 is connected to an input terminal of the first AND gate AND1, an input terminal of the second AND gate AND2, an input terminal of the third AND gate AND3, an input terminal of the fourth AND gate AND4, an input terminal of the second OR gate OR2, and the single-inductor dual-output switching converter TD, respectively;

[0097] The output end of the first OR gate OR1 and the output end of the second OR gate OR2 are both connected to the input end of the first flip-flop RS1, and the output end of the first flip-flop RS1 is respectively connected to the input end of the third flip-flop RS3 and the single-inductor dual-output switching converter TD;

[0098] The output of the fourth comparator COMP4 is connected to the input of the fourth AND gate AND4. The output of the fourth AND gate AND4 is connected to the input of the third flip-flop RS3. The output of the third flip-flop RS3 is connected to the single-inductor dual-output switching converter TD.

[0099] In an embodiment of the present application, a quasi-frequency conversion control method based on a single inductor dual output is provided. Next, based on the above-mentioned quasi-frequency conversion control circuit, a specific quasi-frequency conversion control method is introduced:

[0100] In the embodiment of the present application, the first voltage detection circuit VS1 detects the first output voltage of the first output branch of the single-inductor dual-output switching converter TD to obtain a first voltage signal U o1 and the first output voltage signal U o1 The first compensator EA1 outputs the first voltage signal U o1 and the second voltage reference value signal U ref2 Get the first compensation signal U e1 , and the first compensation signal U e1 Sent to the first comparator COMP1, the first comparator COMP1 according to the first compensation signal U e1 and the sawtooth wave signal SAW to obtain the first voltage signal U s1 , and the first voltage signal U s1 Send to the first AND gate AND1;

[0101] The second voltage detection circuit VS2 detects the second output voltage of the second output branch of the single-inductor dual-output switching converter TD to obtain a second voltage signal U o2 and the second output voltage signal U o2 The second compensator EA2 is sent to the second compensator EA2, and the second compensator EA2 is based on the second output voltage signal U o2 and the first voltage reference value signal U ref1 Get the second compensation signal U e2 , and the second compensation signal U e2 The second comparator COMP2 receives the second compensation signal U e2 and the sawtooth wave signal SAW to obtain the second voltage signal U s2 , and the second voltage signal U s2 Send to the second AND gate AND2;

[0102] It should be emphasized that the function of the first compensator EA1 and the second compensator EA2 is to make the output voltage follow the voltage reference signal. The compensator can be: a proportional regulator, a proportional-integral regulator, a proportional-integral-differential regulator, a type 1 compensator, a type 2 compensator or a type 3 compensator, etc.

[0103] The first current detection circuit IS1 detects the inductor current of the single-inductor dual-output switching converter TD and obtains the inductor current signal i L and the inductor current signal i LThe second current detection circuit IS2 detects the first output current of the first output branch of the single-inductor dual-output switching converter TD and obtains the first output current signal i o1 and the first output current signal i o1 Send to the ratio selector KK;

[0104] The third current detection circuit IS3 detects the second output current of the second output branch of the single-inductor dual-output switching converter TD, and obtains a second output current signal i o2 and the second output current signal i o2 Sent to the ratio selector KK.

[0105] The sample-and-hold device SH samples the inductor current signal i at each clock signal point. L Sampling is performed and held until the end of the current clock cycle to obtain the target inductor current signal i L0 , and the target inductor current signal i L0 Send to the ratio selector KK;

[0106] The proportional selector KK is based on the target inductor current signal i L0 , the first output current signal i o1 and the second output current signal i o2 Get the target current signal i on , and the target current signal i on They are sent to the third comparator COMP3 and the fourth comparator COMP4 respectively.

[0107] The third comparator COMP3 generates a current signal according to the inductor current signal i L and the target current signal i on Compare and obtain the third voltage signal U s3 and the third voltage signal U s3 Sent to the third AND gate AND3; the third AND gate AND3 is based on the third voltage signal U s3 and the first control signal U gs1 , obtain the third trigger signal RR3, and send the third trigger signal RR3 to the second trigger RS2; the second trigger RS2 obtains the first control signal U according to the clock signal clk and the third trigger signal RR3 gs1 and the second control signal U gs2 , and when the second flip-flop RS2 receives only the clock signal clk, the control signal obtained at this time is only the first control signal U gs1 and the first control signal U gs1 The second control signal U is sent to the first AND gate AND1 and the third AND gate AND3 respectively. gs2The first control signal U is sent to the first AND gate AND1, the second OR gate OR2 and the fourth AND gate AND4 respectively. gs1 and the second control signal U gs2 The signals are also sent to the single-inductor dual-output switching converter TD to control the two output branch switching tubes of the single-inductor dual-output switching converter respectively.

[0108] The first AND gate AND1 is connected to the first voltage signal U s1 and the first control signal U gs1 , get the first comparison signal U g1 and the first comparison signal U g1 The signal is sent to the first OR gate OR1, and the second AND gate AND2 is connected to the second voltage signal U s2 and the second control signal U gs2 , get the second comparison signal U g2 and the second comparison signal U g2 Sent to the first OR gate OR1; the first OR gate OR1 is based on the first comparison signal U g1 and the second comparison signal U g2 Get the first trigger signal RR1; and send the first trigger signal RR1 to the first flip-flop RS1; the second OR gate OR2 is based on the clock signal clk and the second control signal U gs2 The first trigger RS1 obtains the third control signal U of the main switch according to the first trigger signal RR1 and the first selection signal SS1. gs0 and the third control signal U gs0 The third control signal U is sent to the single-inductor dual-output switching converter TD to control the main switch of the input main circuit of the single-inductor dual-output switching converter TD. gs0 Send to the third trigger RS3;

[0109] The fourth comparator COMP4 generates a current signal according to the inductor current signal i L and the target current signal i on Compare and obtain the fourth voltage signal U s4 , and the fourth voltage signal U s4 Sent to the fourth AND gate AND4; the fourth AND gate AND4 is based on the fourth voltage signal U s4 and the second control signal U gs2 Obtain a third selection signal SS3, and send the third selection signal SS3 to a third flip-flop RS3;

[0110] The third flip-flop RS3 responds to the third control signal U gs0 and the third selection signal SS3 to obtain the fourth control signal U gsfand the fourth control signal U gsf The signal is sent to the single-inductor dual-output switching converter TD to control the freewheeling switch tube of the single-inductor dual-output switching converter TD.

[0111] In the embodiment of the present application, there are multiple AND gates and OR gates, which all represent logic circuits. The AND gate and OR gate perform logical processing on the input signals of the logic gates. The AND gate can be considered to perform multiplication operations. When the input signals are both high, the output is high, otherwise it is low; the OR gate can be considered to perform addition operations. When the input signals are both high, the output is high, otherwise it is low.

[0112] Since the two output branches adopt different conduction modes, the quasi-frequency control circuit proposed in the embodiment of the present application is based on the characteristics of their respective conduction modes to achieve the control of the output branch of the single-inductor dual-output switching converter to achieve a zero inductor current follow-on value during operation, but without a duration, so as to achieve a combination of the critical conduction mode and the discontinuous conduction mode. At this time, no matter how the load changes, the energy is always in a balanced state, thereby achieving the purpose of eliminating the cross-influence between different output branches.

[0113] Next, we built an experimental platform, conducted experiments on the experimental platform, and obtained experimental results to verify the above method. The verification process and results are as follows:

[0114] To make the description clearer, the following content will use the first output branch of the single inductor dual output as output branch a, and the second output branch as output branch b.

[0115] (1) Using the traditional control method, the inductor current is constant at 2A when the load changes.

[0116] Figure 3 This is the load jump diagram of output branch a, from Figure 3 It can be seen that when the output current of output branch a jumps from 1A to 1.5A, the output voltage overshoot of output branch a is 16.00%, and the adjustment time is about 2ms. The output voltage overshoot of output branch b is 19.17%, and the adjustment time is about 5ms.

[0117] Figure 4 This is the load jump diagram of output branch b, from Figure 4 It can be seen from the figure that when the output current of output branch b jumps from 1A to 1.5A, the output voltage of output branch a has no overshoot, the output voltage of output branch b has an overshoot of 15%, and the adjustment time is about 4ms.

[0118] (2) By adopting the quasi-variable frequency control method proposed in the present invention, when the load changes, the freewheeling value of the inductor current changes with the load.

[0119] Figure 5This is the load jump diagram of output branch a, from Figure 5 It can be seen that when the output current of output branch a jumps from 1A to 1.5A, the overshoot of the output voltage of output branch a is 12.00%, and the adjustment time is about 2ms. The overshoot of the output voltage of output branch b is 8.30%, and the adjustment time is about 3.6ms.

[0120] Figure 6 This is the load jump diagram of output branch b, from Figure 6 It can be seen from the figure that when the output current of output branch b jumps from 1A to 1.5A, the output voltage overshoot of output branch a is 4.00%, and the adjustment time is about 0.6ms. The output voltage overshoot of output branch b is 10%, and the adjustment time is about 2ms.

[0121] Comparing the experimental results of the two methods, Figure 7a and Figure 7b This is a comparison diagram of the output branch cross-influence effect under the quasi-variable frequency control method proposed in the embodiment of this application. Figure 8a and Figure 8b This is a comparison diagram of the effect of voltage overshoot under the quasi-frequency conversion control method proposed in an embodiment of the present application. It can be seen that compared with the traditional control method, the cross-influence of output branch a on output branch b under the quasi-frequency conversion control technology proposed in the present invention is reduced from 2.3V to 1.0V; the cross-influence of output branch b on output branch a is increased from 0V to 0.2V; the overshoot of output branch a is reduced from 0.8V to 0.6V; the overshoot of output branch b is reduced from 1.8V to 1.2V.

[0122] Therefore, it can be observed that the quasi-variable frequency control method proposed in the embodiment of the present application effectively suppresses the cross-influence of output branch a on output branch b, that is, effectively eliminates the cross-influence between the two outputs.

[0123] The above disclosure is merely a preferred embodiment of the present invention and certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A quasi-variable frequency control circuit based on a single-inductor dual-output switching converter, characterized in that: The circuit includes: a voltage detection module, a compensation module, a current detection module, a sample and hold module, a proportional selector, a comparison module, a third comparator, a fourth comparator, a first AND gate, a second AND gate, a third AND gate, a fourth AND gate, a first OR gate, a second OR gate, a first trigger, a second trigger and a third trigger; The input end of the voltage detection module is connected to the single-inductor dual-output switching converter, and the output end of the voltage detection module is also connected to the input end of the compensation module. The output end of the compensation module is respectively connected to the input end of the first AND gate and the input end of the second AND gate through the comparison module. The output end of the first AND gate and the output end of the second AND gate are both connected to the input end of the first OR gate. The input end of the current detection module is connected to the single-inductor dual-output switching converter, and the output end of the current detection module is respectively connected to the input end of the proportional selector, the input end of the third comparator, and the input end of the fourth comparator. The output end of the current detection module is also connected to the input end of the proportional selector through the sample and hold device, and the output end of the proportional selector is respectively connected to the input end of the third comparator and the input end of the fourth comparator; The output end of the third comparator is connected to the input end of the third AND gate, the output end of the third AND gate is connected to the input end of the second flip-flop, and the output end of the second flip-flop is respectively connected to the input end of the first AND gate, the input end of the second AND gate, the input end of the third AND gate, the input end of the fourth AND gate, the input end of the second OR gate, and the single-inductor dual-output switching converter; The output end of the first OR gate and the output end of the second OR gate are both connected to the input end of the first trigger, and the output end of the first trigger is respectively connected to the input end of the third trigger and the single-inductor dual-output switching converter; The output end of the fourth comparator is connected to the input end of the fourth AND gate, the output end of the fourth AND gate is connected to the input end of the third trigger, and the output end of the third trigger is connected to the single-inductor dual-output switching converter; The voltage detection module is used to detect the output voltage of the single-inductor dual-output switching converter to obtain an output voltage signal, and send the output voltage signal to the compensation module; The compensation module is configured to obtain a compensation signal according to the output voltage signal and the voltage reference value signal, and send the compensation signal to the comparison module; The comparison module is configured to compare the compensation signal with the sawtooth wave signal to obtain a first voltage signal and a second voltage signal, and send the first voltage signal and the second voltage signal to the first AND gate and the second AND gate respectively; The current detection module is configured to detect the inductor current and the output current of the single-inductor dual-output switching converter, obtain an inductor current signal and an output current signal, and send the inductor current signal to the sample and hold, the third comparator, and the fourth comparator, respectively, and send the output current signal to the ratio selector; The sample and hold device is used to sample the inductor current signal I at each clock signal point. L Sampling is performed and held until the end of the current clock cycle to obtain the target inductor current signal i L0 and the target inductor current signal i L0 Send to the ratio selector; the proportional selector is configured to obtain a target current signal according to the target inductor current signal and the output current signal, and send the target current signal to the third comparator and the fourth comparator respectively; the third comparator is configured to obtain a third voltage signal by comparing the inductor current signal with the target current signal, and send the third voltage signal to the third AND gate; The third AND gate is configured to obtain a third trigger signal according to the third voltage signal and the first control signal, and send the third trigger signal to the second trigger; the second flip-flop being configured to obtain a first control signal and a second control signal based on the clock signal and the third trigger signal, and to send the first control signal and the second control signal to the single-inductor dual-output switching converter to control branch switches of the single-inductor dual-output switching converter, and to send the first control signal to the first AND gate and the third AND gate, respectively, and to send the second control signal to the first AND gate, the second AND gate, the second OR gate, and the fourth AND gate; the first AND gate being configured to obtain a first comparison signal based on the first output voltage signal and the first control signal, and to send the first comparison signal to the first OR gate, wherein the first output voltage signal is obtained by detecting the first output voltage of the single-inductor dual-output switching converter by the voltage detection module; the second AND gate is configured to obtain a second comparison signal based on the second output voltage signal and the second control signal, and send the second comparison signal to the first OR gate, wherein the second output voltage signal is obtained by detecting the second output voltage of the single-inductor dual-output switching converter by the voltage detection module; The first OR gate is configured to obtain a first trigger signal according to the first comparison signal and the second comparison signal; and send the first trigger signal to the first trigger; the second OR gate is configured to obtain a first selection signal according to the clock signal and the second control signal, and send the first selection signal to the first flip-flop; the first trigger being configured to obtain a third control signal for the main switch according to the first trigger signal and the first selection signal, and to send the third control signal to the single-inductor dual-output switching converter to control the main switch of the single-inductor dual-output switching converter, and further to send the third control signal to the third trigger; the fourth comparator is configured to obtain a fourth voltage signal by comparing the inductor current signal with the target current signal, and send the fourth voltage signal to the fourth AND gate; The fourth AND gate is configured to obtain a third selection signal according to the fourth voltage signal and the second control signal, and send the third selection signal to the third trigger; The third trigger is configured to obtain a fourth control signal according to the third control signal and the third selection signal, and send the fourth control signal to the single-inductor dual-output switching converter to control the freewheeling switch of the single-inductor dual-output switching converter; Wherein, the voltage detection module includes a first voltage detection circuit and a second voltage detection circuit; The input end of the first voltage detection circuit is connected to the output end of the single-inductor dual-output switching converter, and the output end of the first voltage detection circuit is connected to the compensation module; The input end of the second voltage detection circuit is connected to the output end of the single-inductor dual-output switching converter, and the output end of the second voltage detection circuit is connected to the compensation module; Wherein, the compensation module includes a first compensator and a second compensator; Wherein, the input end of the first compensator is connected to the first voltage detection circuit, and the output end of the first compensator is connected to the comparison module; An input terminal of the second compensator is connected to the second voltage detection circuit, and an output terminal of the second compensator is connected to the comparison module; Wherein, the comparison module includes a first comparator and a second comparator; An input terminal of the first comparator is connected to the first compensator, and an output terminal of the first comparator is connected to the first AND gate; An input terminal of the second comparator is connected to the second compensator, and an output terminal of the second comparator is connected to the second AND gate; Wherein, the current detection module includes a first current detection circuit, a second current detection circuit and a third current detection circuit; An input end of the first current detection circuit is connected to the single-inductor dual-output switching converter, and an output end of the first current detection circuit is connected to the sample and hold, the third comparator, and the fourth comparator respectively; An input end of the second current detection circuit is connected to the single-inductor dual-output switching converter, and an output end of the second current detection circuit is connected to the proportional selector; An input end of the third current detection circuit is connected to the single-inductor dual-output switching converter, and an output end of the third current detection circuit is connected to the proportional selector.

2. The circuit according to claim 1, characterized in that The second trigger is used to obtain the first control signal and the second control signal according to the clock signal and the third trigger signal, and also includes: when the second trigger only receives the clock signal, the control signal obtained at this time is the first control signal.

3. A quasi-variable frequency control method based on a single-inductor dual-output switching converter, characterized in that: The method is applied to the circuit according to any one of claims 1 to 2, and the method includes: a voltage detection module detecting an output voltage of the single-inductor dual-output switching converter to obtain an output voltage signal, and sending the output voltage signal to a compensation module; the compensation module obtaining a compensation signal based on the output voltage signal and a voltage reference value signal, and sending the compensation signal to a comparison module; the comparison module comparing the compensation signal with a sawtooth wave signal to obtain a first voltage signal and a second voltage signal, and sending the first voltage signal and the second voltage signal to a first AND gate and a second AND gate, respectively; The current detection module detects the inductor current and the output current of the single-inductor dual-output switching converter to obtain an inductor current signal and an output current signal, and sends the inductor current signal to the sample and hold, the third comparator, and the fourth comparator respectively, and sends the output current signal to the ratio selector; The sample-and-hold device samples the inductor current signal at each clock signal point and holds the sample until the end of the current clock cycle to obtain a target inductor current signal, and sends the target inductor current signal to the ratio selector; The proportional selector obtains a target current signal according to the target inductor current signal and the output current signal, and sends the target current signal to the third comparator and the fourth comparator respectively; The third comparator compares the inductor current signal with the target current signal to obtain a third voltage signal, and sends the third voltage signal to a third AND gate; The third AND gate obtains a third trigger signal according to the third voltage signal and the first control signal, and sends the third trigger signal to the second trigger; The second flip-flop obtains a first control signal and a second control signal according to the third trigger signal and the clock signal, and sends the first control signal and the second control signal to the single-inductor dual-output switching converter to control the branch switches of the single-inductor dual-output switching converter. The second flip-flop also sends the first control signal to the first AND gate and the third AND gate respectively, and sends the second control signal to the first AND gate, the second OR gate, and the fourth AND gate. The first AND gate obtains a first comparison signal according to the first voltage signal and the first control signal, and sends the first comparison signal to the first OR gate; The second AND gate obtains a second comparison signal according to the second voltage signal and the second control signal, and sends the second comparison signal to the first OR gate; The first OR gate obtains a first trigger signal according to the first comparison signal and the second comparison signal; and sends the first trigger signal to the first trigger; The second OR gate obtains a first selection signal according to the clock signal and the second control signal, and sends the first selection signal to the first flip-flop; The first trigger obtains a third control signal for the main switch according to the first trigger signal and the first selection signal, sends the third control signal to the single-inductor dual-output switching converter to control the main switch of the single-inductor dual-output switching converter, and further sends the third control signal to a third trigger; The fourth comparator compares the inductor current signal with the target current signal to obtain a fourth voltage signal, and sends the fourth voltage signal to the fourth AND gate; The fourth AND gate obtains a third selection signal according to the fourth voltage signal and the second control signal, and sends the third selection signal to the third trigger; The third trigger obtains a fourth control signal according to the third control signal and the third selection signal, and sends the fourth control signal to the single-inductor dual-output switching converter to control the freewheeling switch tube of the single-inductor dual-output switching converter.

4. The method according to claim 3, characterized in that The voltage detection module detects the output voltage of the single-inductor dual-output switching converter to obtain an output voltage signal, and sends the output voltage signal to the compensation module; the compensation module obtains a compensation signal based on the output voltage signal and a voltage reference value signal, and sends the compensation signal to the comparison module; The comparison module compares the compensation signal and the sawtooth wave signal to obtain a first voltage signal and a second voltage signal, and sends the first voltage signal and the second voltage signal to a first AND gate and a second AND gate, respectively, specifically including: The first voltage detection circuit in the voltage detection module detects the first output voltage of the single-inductor dual-output switching converter to obtain a first output voltage signal, and sends the first output voltage signal to the compensation module; The second voltage detection circuit in the voltage detection module detects the second output voltage of the single-inductor dual-output switching converter to obtain a second output voltage signal, and sends the second output voltage signal to the compensation module; The first compensator in the compensation module obtains a first compensation signal according to the first output voltage signal and the voltage reference value signal, and sends the first compensation signal to the comparison module; The second compensator in the compensation module obtains a second compensation signal according to the second output voltage signal and the voltage reference value signal, and sends the second compensation signal to the comparison module; The first comparator in the comparison module obtains a first voltage signal according to the first compensation signal and the sawtooth wave signal, and sends the first voltage signal to the first AND gate; The second comparator in the comparison module obtains a second voltage signal according to the second compensation signal and the sawtooth wave signal, and sends the second voltage signal to the second AND gate.

5. The method according to claim 3, characterized in that: The current detection module detects the inductor current and the output current of the single-inductor dual-output switching converter to obtain an inductor current signal and an output current signal, and sends the inductor current signal to the sample and hold, the third comparator, and the fourth comparator respectively, and sends the output current signal to the ratio selector, specifically including: The first current detection circuit in the current detection module detects the inductor current of the single-inductor dual-output switching converter to obtain the inductor current signal, and sends the inductor current signal to the sample and hold, the third comparator, and the fourth comparator respectively; The second current detection circuit in the current detection module detects the first output current of the single-inductor dual-output switching converter to obtain the first output current signal, and sends the first output current signal to the proportional selector; The third current detection circuit in the current detection module detects the second output current of the single-inductor dual-output switching converter, obtains the second output current signal, and sends the second output current signal to the proportional selector.

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