CN116345908A - Buck circuit and DC-DC chip - Google Patents

Buck circuit and DC-DC chip Download PDF

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Publication number
CN116345908A
CN116345908A CN202310601970.6A CN202310601970A CN116345908A CN 116345908 A CN116345908 A CN 116345908A CN 202310601970 A CN202310601970 A CN 202310601970A CN 116345908 A CN116345908 A CN 116345908A
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output
feedback
transistor
unit
buck circuit
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CN202310601970.6A
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CN116345908B (en
Inventor
樊茂
刘敬东
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Yingli Semiconductor Shanghai Co ltd
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Yingli Semiconductor Shanghai Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

The invention discloses a buck circuit and a DC-DC chip. The Buck circuit comprises a feedback regulating unit; the input end of the feedback regulating unit is connected with the output end of the buck circuit, the output end of the feedback regulating unit is connected with the output end of the feedback unit and the feedback signal input end of the driving unit, and the feedback regulating unit is used for regulating the feedback signal output by the feedback unit according to the conversion voltage; the driving unit is also used for controlling the on time of the input transistor and the output transistor according to the feedback signal. By arranging the feedback regulating unit between the output end of the buck circuit and the output end of the feedback unit, the feedback regulating unit can directly regulate the feedback signal output by the feedback unit according to the conversion voltage output by the output end of the buck circuit, so that the regulating process of the feedback signal is reduced, and the feedback response speed of the buck circuit can be improved.

Description

Buck circuit and DC-DC chip
Technical Field
The embodiment of the invention relates to the technical field of voltage conversion, in particular to a buck circuit and a DC-DC chip.
Background
In an electronic apparatus using a direct current source, a voltage converter is required to convert the voltage of a power supply into a desired operating voltage. buck circuits, a widely used buck conversion circuit, are mainly used for direct current to direct current (DC-DC) buck conversion, and are generally applicable to the field of low-voltage and high-current applications.
Fig. 1 is a schematic diagram of a buck circuit according to the prior art. As shown in fig. 1, the buck circuit includes a pulse width modulator 101, an N-type transistor Mn1, a P-type transistor Mp1, an error amplifier EA, a comparator 102, a current sensing and compensating block 103, a first voltage dividing resistor Rt1, a second voltage dividing resistor Rt2, a detection resistor Rt3, a switching transistor Mp0, a clock generator 104, and a zero point detector 105. The specific connection relation is shown in figure 1. During operation of the buck circuit, the clock generator 104 is configured to provide a clock signal to the buck circuit and the zero detector 105 is configured to perform zero detection. The pwm 101 controls the N-type transistor Mn1 and the P-type transistor Mp1 to be turned on in a time-sharing manner according to the power signal vdd and the target voltage vout required to be output by the buck circuit, thereby realizing dc source conversion. The first voltage dividing resistor Rt1 and the second voltage dividing resistor Rt2 divide the target voltage vout and output the divided voltage to the negative input terminal in 1-of the error amplifier EA, and the positive input terminal in1+ of the error amplifier EA is connected to the reference signal. The error amplifier EA forms a feedback signal according to the divided voltage signal of the target voltage vout and the reference signal, and outputs the feedback signal to the negative input terminal in 2-of the comparator 102, and the positive input terminal in2+ of the comparator 102 is connected to the output terminal of the current sensing and compensating module 103. When the P-type transistor Mp1 is turned on, the switching transistor Mp0 is turned on, the current sensing and compensating module 103 detects the current of two poles of the P-type transistor Mp1 through the detection resistor Rt3 and outputs the current to the current sensing and compensating module 103, so that the current sensing and compensating module 103 obtains a current signal flowing through the P-type transistor Mp1, and outputs the current signal to the non-inverting input terminal in2+ of the comparator 102 after compensation, so that the comparator 102 forms a comparison signal according to the current signal and a feedback signal and outputs the comparison signal to the pulse width modulator 101, so that the pulse width modulator 101 adjusts the duty ratio of the pulse width modulation signal according to the comparison signal, thereby controlling the on time of the N-type transistor Mn1 and the P-type transistor Mp 1.
In the above process, the divided voltage signal of the target voltage vout is first output to the negative phase input terminal in 1-of the error amplifier EA, and the error amplifier EA forms a feedback signal according to the divided voltage signal of the target voltage vout and the reference signal, i.e., the output of the error amplifier EA is controlled by the feedback signal. And then output to the comparator 102, and the comparator 102 adjusts the duty ratio of the pulse width modulation signal according to the current signal and the feedback signal, so that the feedback response speed is slow.
Disclosure of Invention
The invention provides a buck circuit and a DC-DC chip, which are used for improving the feedback response speed of the buck circuit.
In a first aspect, an embodiment of the present invention provides a buck circuit, including a driving unit, an input transistor, an output transistor, a feedback unit, a feedback adjustment unit, a voltage division unit, and an output storage unit;
the first output end and the second output end of the driving unit are respectively connected with the control electrode of the input transistor and the control electrode of the output transistor, the first electrode of the input transistor is connected with the power input end, the second electrode of the input transistor and the first electrode of the output transistor are connected with the first input end of the output storage unit, the second electrode of the output transistor and the second input end of the output storage unit are connected with the first potential end, and the output end of the output storage unit is used as the output end of the buck circuit; the driving unit is used for controlling the input transistor and the output transistor to conduct in a time-sharing way, the input transistor is used for providing electric energy for the output storage unit when the input transistor is conducted, and the output transistor is used for communicating a discharge loop of the output storage unit when the output transistor is conducted;
the first input end of the voltage dividing unit is connected with the output end of the buck circuit, the second input end of the voltage dividing unit is connected with the first potential end, the output end of the voltage dividing unit is connected with the second input end of the feedback unit, the first input end of the feedback unit is connected with the reference signal input end, the output end of the feedback unit is connected with the output end of the feedback regulating unit and the feedback signal input end of the driving unit, and the input end of the feedback regulating unit is connected with the output end of the buck circuit; the voltage dividing unit is used for dividing the converted voltage output by the output end of the buck circuit to form a divided signal; the feedback unit is used for forming a feedback signal according to the voltage division signal and a reference signal provided by the reference signal input end; the feedback regulation unit is used for regulating the feedback signal according to the conversion voltage; the driving unit is further used for controlling the on time of the input transistor and the output transistor according to the feedback signal.
Optionally, the feedback adjustment unit includes a high frequency domain feedback module and an adjustment module;
the input end of the Gao Pinyu feedback module is connected with the output end of the buck circuit, the output end of the Gao Pinyu feedback module is connected with the input end of the adjusting module, and the output end of the adjusting module is connected with the output end of the feedback unit and the feedback signal input end of the driving unit; the Gao Pinyu feedback module is used for forming a high-frequency domain feedback signal according to the high-frequency component in the converted voltage, and the adjusting module is used for adjusting the feedback signal according to the high-frequency domain feedback signal and outputting the feedback signal to the feedback signal input end of the driving unit.
Optionally, the Gao Pinyu feedback module comprises a high-pass filtering sub-module, an initializing sub-module and a unidirectional conduction device;
the input end of the high-pass filtering sub-module is connected with the output end of the buck circuit, the output end of the high-pass filtering sub-module and the output end of the initializing sub-module are connected with the cathode of the unidirectional conduction device, and the anode of the unidirectional conduction device is connected with the input end of the regulating module; the high-pass filtering submodule is used for acquiring a high-frequency component in the conversion voltage; the initialization submodule is used for providing an initialization potential for the cathode of the unidirectional conduction device; the unidirectional conduction device is used for outputting high-frequency components in the conversion voltage when the voltage difference between the anode and the cathode is larger than a threshold voltage.
Optionally, the initialization submodule includes a current source and a first resistor;
the input end of the current source is connected with the power input end, the output end of the current source is connected with the first end of the first resistor and serves as the output end of the initialization submodule, and the second end of the first resistor is connected with the first potential end.
Optionally, the high-pass filtering submodule includes a filter capacitor;
the first pole of the filter capacitor is connected with the output end of the buck circuit, and the second pole of the filter capacitor is connected with the first end of the first resistor and serves as the output end of the high-pass filter submodule.
Optionally, the unidirectional conduction device is a diode.
Optionally, the regulation module includes a first transistor, a second transistor, and a second resistor;
the first pole of the first transistor and the first pole of the second transistor are connected with the power input end, and the second pole of the first transistor, the grid electrode of the first transistor and the grid electrode of the second transistor are connected with the first end of the second resistor and serve as input ends of the regulating module; the second end of the second resistor is connected with the first potential end, and the second pole of the second transistor is used as the output end of the regulating module.
Optionally, the feedback unit includes an error amplifier;
the positive phase input end of the error amplifier is connected with the reference signal input end, the negative phase input end of the error amplifier is connected with the output end of the voltage dividing unit, and the output end of the error amplifier is connected with the output end of the feedback regulating unit and the feedback signal input end of the driving unit.
Optionally, the buck circuit further includes a current sensing unit, the driving unit including a comparator and a pulse width modulator;
the current sensing unit is connected with the input transistor and is used for sensing a current signal flowing through the input transistor when the input transistor is turned on; the positive phase input end of the comparator is connected with the current sensing unit, the negative phase input end of the comparator is used as a feedback signal input end of the driving unit, the output end of the comparator is connected with the pulse width modulator, and the pulse width modulator is respectively connected with the control electrode of the input transistor and the control electrode of the output transistor.
In a second aspect, an embodiment of the present invention further provides a DC-DC chip, including the buck circuit according to the first aspect.
According to the technical scheme provided by the embodiment of the invention, the feedback regulating unit is arranged between the output end of the buck circuit and the output end of the feedback unit, and can directly regulate the feedback signal output by the feedback unit according to the conversion voltage output by the output end of the buck circuit, so that the regulation process of the feedback signal is reduced, and the feedback response speed of the buck circuit can be improved.
Drawings
Fig. 1 is a schematic diagram of a buck circuit according to the prior art;
fig. 2 is a schematic structural diagram of a buck circuit according to an embodiment of the present invention;
fig. 3 is a schematic diagram of another buck circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a high-frequency domain feedback module according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of an adjusting module according to an embodiment of the present invention;
fig. 6 is a schematic diagram of another buck circuit according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
Fig. 2 is a schematic structural diagram of a buck circuit according to an embodiment of the present invention. As shown in fig. 2, the buck circuit includes a driving unit 110, an input transistor M1, an output transistor M2, a feedback unit 120, a feedback adjustment unit 130, a voltage division unit 140, and an output storage unit 150; the first output terminal and the second output terminal of the driving unit 110 are respectively connected with the control electrode of the input transistor M1 and the control electrode of the output transistor M2, the first electrode of the input transistor M1 is connected with the power input terminal VDD, the second electrode of the input transistor M1 and the first electrode of the output transistor M2 are connected with the first input terminal of the output memory unit 150, the second electrode of the output transistor M2 and the second input terminal of the output memory unit 150 are connected with the first potential terminal V1, and the output terminal of the output memory unit 150 is taken as the output terminal OUT of the buck circuit; the driving unit 110 is configured to control the input transistor M1 and the output transistor M2 to be turned on in a time-sharing manner, the input transistor M1 is configured to provide the output memory unit 150 with electric energy when turned on, and the output transistor M2 is configured to communicate with a discharge circuit of the output memory unit 150 when turned on; the first input end of the voltage division unit 140 is connected with the output end OUT of the buck circuit, the second input end of the voltage division unit 140 is connected with the first potential end V1, the output end of the voltage division unit 140 is connected with the second input end of the feedback unit 120, the first input end of the feedback unit 120 is connected with the reference signal input end VREF, the output end of the feedback unit 120 is connected with the output end of the feedback regulation unit 130 and the feedback signal input end of the driving unit 110, and the input end of the feedback regulation unit 130 is connected with the output end OUT of the buck circuit; the voltage dividing unit 140 is configured to divide the converted voltage output by the output terminal OUT of the buck circuit to form a divided signal; the feedback unit 120 is configured to form a feedback signal according to the divided voltage signal and a reference signal provided by the reference signal input terminal VREF; the feedback adjustment unit 130 is configured to adjust the feedback signal according to the converted voltage; the driving unit 110 is further configured to control the on-time of the input transistor M1 and the output transistor M2 according to the feedback signal.
Specifically, the driving unit 110 may form a control signal according to the power supplied from the power input terminal VDD and the switching voltage required by the output terminal OUT, to control the input transistor M1 and the output transistor M2 to be turned on in a time-sharing manner. When the driving unit 110 controls the input transistor M1 to be turned on, the output transistor M2 is turned off, and the power signal provided by the power input terminal VDD is transmitted to the output storage unit 150 through the input transistor M1, so that the output storage unit 150 can store electric energy. When the driving unit 110 controls the output transistor M2 to be turned on, the input transistor M1 is turned off, and the output transistor M2 may be connected to the discharge loop of the output memory unit 150, so that the output memory unit 150 may be discharged, thereby providing power through the output terminal OUT. In the above process, the driving unit 110 can control the electric energy stored in the output storage unit 150 by controlling the time of time-sharing turn-on of the input transistor M1 and the output transistor M2, and further can control the voltage when the output storage unit 150 discharges, so as to realize the conversion of the dc voltage. In which fig. 2 shows an exemplary output storage unit 150 comprising an inductance and a capacitance for storing electrical energy, while the converted voltage may be filtered.
After the output terminal OUT of the buck circuit outputs the converted voltage, the voltage dividing unit 140 divides the converted voltage and outputs the divided voltage to the feedback unit 120, and the feedback unit 120 forms a feedback signal according to the divided voltage signal of the converted voltage and the reference signal provided by the reference signal input terminal VREF. Meanwhile, the feedback adjustment unit 130 may directly form an adjustment signal according to the converted voltage, and output the adjustment signal to the output terminal of the feedback unit 120 to adjust the feedback signal. The driving unit 110 is then outputted such that the driving unit 110 directly adjusts the on-time of the input transistor M1 and the output transistor M2 according to the adjusted feedback signal, so that the switching voltage outputted from the output terminal OUT can be adjusted. In the above process, the feedback adjusting unit 130 may directly adjust the feedback signal according to the converted voltage, thereby reducing the adjusting process of the feedback signal, and improving the feedback response speed of the buck circuit.
According to the technical scheme, the feedback adjusting unit is arranged between the output end of the buck circuit and the output end of the feedback unit, and can directly adjust the feedback signal output by the feedback unit according to the conversion voltage output by the output end of the buck circuit, so that the adjusting process of the feedback signal is reduced, and the feedback response speed of the buck circuit can be improved.
Fig. 3 is a schematic diagram of another buck circuit according to an embodiment of the present invention. As shown in fig. 3, the feedback adjustment unit 130 includes a high frequency domain feedback module 131 and an adjustment module 132; the input end of the high-frequency domain feedback module 131 is connected with the output end OUT of the buck circuit, the output end of the high-frequency domain feedback module 131 is connected with the input end of the adjusting module 132, and the output end of the adjusting module 132 is connected with the output end of the feedback unit 120 and the feedback signal input end of the driving unit 110; the high frequency domain feedback module 131 is configured to form a high frequency domain feedback signal according to the high frequency component in the converted voltage, and the adjusting module 132 is configured to adjust the feedback signal according to the high frequency domain feedback signal and output the feedback signal to the feedback signal input end of the driving unit 110.
Specifically, the high frequency domain feedback module 131 may acquire a high frequency component in the converted voltage. Wherein the high frequency component may comprise an alternating current component. When the conversion voltage output by the output terminal OUT of the buck circuit is unchanged, the high-frequency component in the conversion voltage is unchanged, so that the high-frequency feedback module 131 cannot output the high-frequency feedback signal. At this time, the adjustment module 132 cannot adjust the feedback signal according to the high frequency domain feedback signal. When the switching voltage output from the output terminal OUT of the buck circuit suddenly changes, for example, the load of the buck circuit suddenly increases, so that the switching voltage of the buck circuit suddenly decreases. At this time, the voltage of the high-frequency component in the converted voltage obtained by the high-frequency domain feedback module 131 drops, so that the high-frequency domain feedback module 131 can output a high-frequency domain feedback signal. The voltage of the high frequency domain feedback signal will also drop at this time. When the high-frequency-domain feedback signal is output to the adjusting module 132 and the voltage of the high-frequency-domain feedback signal decreases, the adjusting module 132 can increase the current output by the high-frequency-domain feedback signal and load the current to the output end of the feedback unit 120, so that the voltage of the output end of the feedback unit 120 increases, that is, the voltage of the feedback signal increases. And then output to the feedback signal input end of the driving unit 110, so that the driving unit 110 controls the on time of the input transistor M1 and the output transistor M2 according to the adjusted feedback signal, thereby quickly adjusting the conversion voltage output by the output end OUT of the buck circuit and improving the feedback response speed of the buck circuit.
Fig. 4 is a schematic structural diagram of a high frequency domain feedback module according to an embodiment of the present invention. As shown in fig. 3 and 4, the high frequency domain feedback module 131 includes a high pass filtering sub-module 1311, an initialization sub-module 1312, and a unidirectional flux device 1313; the input end IN1 of the high-pass filtering submodule 1311 is connected with the output end OUT of the buck circuit, the output end of the high-pass filtering submodule 1311 and the output end of the initializing submodule 1312 are connected with the cathode of the unidirectional conduction device 1313, and the anode of the unidirectional conduction device 1313 is connected with the input end of the regulating module 132; the high-pass filtering submodule 1311 is used for acquiring high-frequency components in the converted voltage; the initialization submodule 1312 is used for providing an initialization potential for the cathode of the unidirectional conductive device 1313; unidirectional pass device 1313 is used to output a high frequency component in the switching voltage when the anode-to-cathode voltage differential is greater than the threshold voltage.
Specifically, the high-pass filtering submodule 1311 may filter the converted voltage, filter the direct-current component in the converted voltage, and output the high-frequency component to the cathode of the unidirectional conductive device 1313. Initialization submodule 1312 may provide an initialization voltage for the cathode of unidirectional pass device 1313. When the conversion voltage output by the output end OUT of the buck circuit is unchanged, a high-frequency component in the conversion voltage is unchanged, the cathode potential of the unidirectional conduction device 1313 is the sum of the initialization potential and the high-frequency component, at the moment, the voltage difference between the anode and the cathode of the unidirectional conduction device 1313 is smaller than the threshold voltage, and the unidirectional conduction device 1313 is in an off state. The anode of the unidirectional conduction device 1313 serves as the output terminal OUT1 of the high-frequency domain feedback module 131, and at this time, the high-frequency component in the converted voltage cannot be output to the adjustment module 132 through the unidirectional conduction device 1313, that is, the high-frequency domain feedback module 131 cannot output the high-frequency domain feedback signal. At this time, the adjustment module 132 cannot adjust the feedback signal according to the high frequency domain feedback signal. When the conversion voltage output by the output terminal OUT of the buck circuit suddenly drops, the voltage of the high-frequency component in the conversion voltage drops, the cathode potential of the unidirectional conduction device 1313 drops along with the high-frequency component, so that the voltage difference between the anode and the cathode of the unidirectional conduction device 1313 is larger than the threshold voltage, the unidirectional conduction device 1313 is in a conduction state, the high-frequency component in the conversion voltage is output to the adjustment module 132 through the unidirectional conduction device 1313, so that the adjustment module 132 can directly adjust the current of the adjustment module 132 according to the high-frequency component, the current output by the adjustment module 132 increases, and the current is loaded to the output terminal of the feedback unit 120, so that the voltage of the output terminal of the feedback unit 120 increases, namely the voltage of the feedback signal increases. And then output to the feedback signal input end of the driving unit 110, so that the driving unit 110 controls the on time of the input transistor M1 and the output transistor M2 according to the adjusted feedback signal, thereby quickly adjusting the conversion voltage output by the output end OUT of the buck circuit and improving the feedback response speed of the buck circuit.
Illustratively, unidirectional conductive device 1313 may be a diode.
Continuing with reference to 4, initialization submodule 1312 includes a current source I1 and a first resistor R1; the input terminal of the current source I1 is connected to the power input terminal VDD, the output terminal of the current source I1 is connected to the first terminal of the first resistor R1, and the second terminal of the first resistor R1 is connected to the first potential terminal V1 as the output terminal of the initialization submodule 1312.
Specifically, the current source I1 may provide a current signal to the first resistor R1, so that both ends of the first resistor R1 have a voltage drop, that is, the voltage drop vr1=r1×i1 between both ends of the first resistor R1; wherein R1 is the resistance of the first resistor R1, and I1 is the current signal provided by the current source I1. Meanwhile, the second end of the first resistor R1 is connected to the first potential end V1, so that the potential of the second end of the first resistor R1 is fixed to the first potential provided by the first potential end V1. At this time, the first end potential of the first resistor R1 is the sum of the first potential and the voltage drop across the first resistor R1, and is used as the cathode initialization voltage of the unidirectional conductive device 1313.
With continued reference to fig. 4, the high pass filter submodule 1311 includes a filter capacitor C1; the first pole of the filter capacitor C1 is connected to the output terminal OUT of the buck circuit, and the second pole of the filter capacitor C1 is connected to the first end of the first resistor R1 and is used as the output terminal of the high-pass filter submodule 1311.
Specifically, the filter capacitor C1 may block dc communication to filter dc components in the converted voltage. Meanwhile, the filter capacitor C1 and the first resistor R1 may form a resistive-capacitive filter circuit for filtering specific frequency components in the converted voltage, and then outputting high frequency components to the cathode of the unidirectional conductive device 1313.
It should be noted that, fig. 4 illustrates, by way of example only, that the high-pass filtering submodule 1311 includes a filter capacitor C1. In other embodiments, the high-pass filtering submodule 1311 may further include other devices and have other connection manners, which only needs to satisfy the effect of the high-pass filtering, which is not limited herein.
Fig. 5 is a schematic structural diagram of an adjusting module according to an embodiment of the present invention. As shown in fig. 3 and 5, the adjusting module 132 includes a first transistor T1, a second transistor T2, and a second resistor R2; the first pole of the first transistor T1 and the first pole of the second transistor T2 are connected to the power input terminal VDD, and the second pole of the first transistor T1, the gate of the first transistor T1 and the gate of the second transistor T2 are connected to the first terminal of the second resistor R2 and serve as the input terminal IN2 of the adjustment module 132; the second terminal of the second resistor R2 is connected to the first potential terminal V1, and the second terminal of the second transistor T2 serves as the output terminal OUT2 of the adjustment module 132.
Specifically, the first transistor T1 and the second transistor T2 may be connected back-to-back to form a current mirror for forming a current signal according to a first polarity potential of the first transistor T1 and a gate potential of the first transistor T1, and then mirrored through the second transistor T2 and output by the second transistor T2. The first electrode potential of the first transistor T1 is unchanged, and is a power supply provided by the power supply input terminal VDD. When the conversion voltage output at the output end OUT of the buck circuit is unchanged, the high-frequency component in the conversion voltage is unchanged, the cathode potential of the unidirectional conduction device 1313 is the sum of the initialization potential and the high-frequency component, at this time, the voltage difference between the anode and the cathode of the unidirectional conduction device 1313 is smaller than the threshold voltage, the unidirectional conduction device 1313 is in an off state, the high-frequency component in the conversion voltage cannot be output to the adjustment module 132 through the unidirectional conduction device 1313, that is, the high-frequency domain feedback module 131 cannot output the high-frequency domain feedback signal. At this time, the gate potential of the first transistor T1 is unchanged, and is the sum of the voltage drops across the first potential terminal V1 and the second resistor R2. The voltage difference between the first pole and the gate of the first transistor T1 is not changed, the current passing through the first transistor T1 is not changed, and the current signal provided by the second transistor T2 to the feedback unit 120 is not changed, so that the feedback signal cannot be adjusted. When the conversion voltage output by the output terminal OUT of the buck circuit suddenly drops, the voltage of the high-frequency component in the conversion voltage drops, the cathode potential of the unidirectional conduction device 1313 drops along with the high-frequency component, so that the voltage difference between the anode and the cathode of the unidirectional conduction device 1313 is larger than the threshold voltage, the unidirectional conduction device 1313 is in a conducting state, the high-frequency component in the conversion voltage is output to the gate of the first transistor T1 through the unidirectional conduction device 1313, at this time, the gate potential of the first transistor T1 drops, that is, the voltage difference between the first pole and the gate of the first transistor T1 increases, the current signal provided by the feedback unit 120 increases through the current increase of the first transistor T1, and the voltage of the output terminal of the feedback unit 120 increases through the second transistor T2, that is, the voltage of the feedback signal increases. And then output to the feedback signal input end of the driving unit 110, so that the driving unit 110 controls the on time of the input transistor M1 and the output transistor M2 according to the adjusted feedback signal, thereby quickly adjusting the conversion voltage output by the output end OUT of the buck circuit and improving the feedback response speed of the buck circuit.
Fig. 6 is a schematic diagram of another buck circuit according to an embodiment of the present invention. As shown in fig. 6, the feedback unit 120 includes an error amplifier EA; the positive phase input terminal In1+ of the error amplifier EA is connected to the reference signal input terminal VREF, the negative phase input terminal IN 1-of the error amplifier EA is connected to the output terminal of the voltage dividing unit 140, and the output terminal of the error amplifier EA is connected to the output terminal of the feedback adjustment unit 130 and the feedback signal input terminal of the driving unit 110.
Specifically, the error amplifier EA has an equivalent impedance. When the current signal output by the feedback adjustment module 130 is output to the output terminal of the error amplifier EA, the output terminal potential of the error amplifier EA can be increased through the equivalent impedance of the error amplifier EA itself to adjust the feedback signal. And then synchronously output to the feedback signal input end of the driving unit 110, so that the driving unit 110 can control the on time of the input transistor M1 and the output transistor M2 according to the adjusted feedback signal, thereby quickly adjusting the conversion voltage output by the output end OUT of the buck circuit and improving the feedback response speed of the buck circuit.
With continued reference to fig. 6, the buck circuit further includes a current sensing unit 160, and the driving unit 110 includes a comparator COMP and a pulse width modulator PWM; the current sensing unit 160 is connected to the input transistor M1, and the current sensing unit 160 is configured to sense a current signal flowing through the input transistor M1 when the input transistor M1 is turned on; the positive phase input terminal in2+ of the comparator COMP is connected to the current sensing unit 160, the negative phase input terminal IN 2-of the comparator COMP is used as a feedback signal input terminal of the driving unit 110, the output terminal of the comparator COMP is connected to the pulse width modulator PWM, and the pulse width modulator PWM is connected to the control electrode of the input transistor M1 and the control electrode of the output transistor M2, respectively.
Specifically, the current sensing unit 160 may include a sensing resistor R3, a measurement switching transistor M3, and a current sensing and compensating module 161, and when the input transistor M1 is turned on, the measurement switching transistor M3 is simultaneously turned on, so that the sensing resistor R3 is connected in parallel between the first and second poles of the input transistor M1, thereby acquiring a voltage difference across the input transistor M1, and outputting to the current sensing and compensating module 161. The current sensing and compensating module 161 determines a current signal flowing through the input transistor M1 according to a voltage difference across the input transistor M1 and a resistance value of the sensing resistor R3, and outputs the current signal to the non-inverting input terminal in2+ of the comparator COMP. The negative input IN 2-of the comparator COMP is connected to the output of the feedback unit 120 and to the output of the feedback regulation unit 130. The current signal may be a triangular wave signal, and the feedback signal may be a climbing signal.
When the conversion voltage output by the output end OUT of the buck circuit is unchanged, the feedback signal is unchanged, the time when the current signal is larger than the feedback signal is unchanged, and the time when the comparator COMP outputs a high level is unchanged, so that the duty ratio of the pulse width modulation signal output by the pulse width modulator PWM is unchanged, namely the on time of the input transistor M1 and the output transistor M2 is unchanged. When the adjusted feedback signal increases, the time that the current signal is greater than the feedback signal decreases, and the time that the comparator COMP outputs a high level decreases, so that the duty ratio of the PWM signal output by the PWM can be adjusted to decrease, the on time of the input transistor M1 increases, the on time of the output transistor M2 decreases, the electric energy stored in the output storage unit 150 increases, and the switching voltage output by the output terminal OUT of the buck circuit increases.
With continued reference to fig. 6, the voltage dividing unit 140 may include a fourth resistor R4 and a fifth resistor R5, where a first end of the fourth resistor R4 is connected to the output terminal OUT of the buck circuit, a second end of the fourth resistor R4 is connected to a first end of the fifth resistor R5, and the first end of the fifth resistor R5 is connected to the first potential terminal V1 as an output terminal of the voltage dividing unit 140. The voltage division of the conversion voltage can be achieved by the fourth resistor R4 and the fifth resistor R5.
The embodiment of the invention also provides a DC-DC chip. The DC-DC chip comprises the buck circuit provided by any embodiment of the invention.
The DC-DC chip comprises the buck circuit provided by any embodiment of the invention, so that the DC-DC chip has the beneficial effects of the buck circuit provided by any embodiment of the invention, and the description is omitted herein.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims (10)

1. The buck circuit is characterized by comprising a driving unit, an input transistor, an output transistor, a feedback unit, a feedback regulating unit, a voltage dividing unit and an output storage unit;
the first output end and the second output end of the driving unit are respectively connected with the control electrode of the input transistor and the control electrode of the output transistor, the first electrode of the input transistor is connected with the power input end, the second electrode of the input transistor and the first electrode of the output transistor are connected with the first input end of the output storage unit, the second electrode of the output transistor and the second input end of the output storage unit are connected with the first potential end, and the output end of the output storage unit is used as the output end of the buck circuit; the driving unit is used for controlling the input transistor and the output transistor to conduct in a time-sharing way, the input transistor is used for providing electric energy for the output storage unit when the input transistor is conducted, and the output transistor is used for communicating a discharge loop of the output storage unit when the output transistor is conducted;
the first input end of the voltage dividing unit is connected with the output end of the buck circuit, the second input end of the voltage dividing unit is connected with the first potential end, the output end of the voltage dividing unit is connected with the second input end of the feedback unit, the first input end of the feedback unit is connected with the reference signal input end, the output end of the feedback unit is connected with the output end of the feedback regulating unit and the feedback signal input end of the driving unit, and the input end of the feedback regulating unit is connected with the output end of the buck circuit; the voltage dividing unit is used for dividing the converted voltage output by the output end of the buck circuit to form a divided signal; the feedback unit is used for forming a feedback signal according to the voltage division signal and a reference signal provided by the reference signal input end; the feedback regulation unit is used for regulating the feedback signal according to the conversion voltage; the driving unit is further used for controlling the on time of the input transistor and the output transistor according to the feedback signal.
2. The buck circuit according to claim 1, wherein the feedback conditioning unit includes a high frequency domain feedback module and a conditioning module;
the input end of the Gao Pinyu feedback module is connected with the output end of the buck circuit, the output end of the Gao Pinyu feedback module is connected with the input end of the adjusting module, and the output end of the adjusting module is connected with the output end of the feedback unit and the feedback signal input end of the driving unit; the Gao Pinyu feedback module is used for forming a high-frequency domain feedback signal according to the high-frequency component in the converted voltage, and the adjusting module is used for adjusting the feedback signal according to the high-frequency domain feedback signal and outputting the feedback signal to the feedback signal input end of the driving unit.
3. The buck circuit of claim 2, wherein the Gao Pinyu feedback module includes a high pass filter sub-module, an initialization sub-module, and a unidirectional pass device;
the input end of the high-pass filtering sub-module is connected with the output end of the buck circuit, the output end of the high-pass filtering sub-module and the output end of the initializing sub-module are connected with the cathode of the unidirectional conduction device, and the anode of the unidirectional conduction device is connected with the input end of the regulating module; the high-pass filtering submodule is used for acquiring a high-frequency component in the conversion voltage; the initialization submodule is used for providing an initialization potential for the cathode of the unidirectional conduction device; the unidirectional conduction device is used for outputting high-frequency components in the conversion voltage when the voltage difference between the anode and the cathode is larger than a threshold voltage.
4. A buck circuit according to claim 3, wherein the initialisation sub-module comprises a current source and a first resistor;
the input end of the current source is connected with the power input end, the output end of the current source is connected with the first end of the first resistor and serves as the output end of the initialization submodule, and the second end of the first resistor is connected with the first potential end.
5. The buck circuit according to claim 4, wherein the high pass filter sub-module includes a filter capacitor;
the first pole of the filter capacitor is connected with the output end of the buck circuit, and the second pole of the filter capacitor is connected with the first end of the first resistor and serves as the output end of the high-pass filter submodule.
6. A buck circuit according to claim 3, wherein the unidirectional conducting device is a diode.
7. The buck circuit of claim 2, wherein the regulation module includes a first transistor, a second transistor, and a second resistor;
the first pole of the first transistor and the first pole of the second transistor are connected with the power input end, and the second pole of the first transistor, the grid electrode of the first transistor and the grid electrode of the second transistor are connected with the first end of the second resistor and serve as input ends of the regulating module; the second end of the second resistor is connected with the first potential end, and the second pole of the second transistor is used as the output end of the regulating module.
8. The buck circuit according to claim 1, wherein the feedback unit includes an error amplifier;
the positive phase input end of the error amplifier is connected with the reference signal input end, the negative phase input end of the error amplifier is connected with the output end of the voltage dividing unit, and the output end of the error amplifier is connected with the output end of the feedback regulating unit and the feedback signal input end of the driving unit.
9. The buck circuit according to claim 1, further comprising a current sense unit, the drive unit including a comparator and a pulse width modulator;
the current sensing unit is connected with the input transistor and is used for sensing a current signal flowing through the input transistor when the input transistor is turned on; the positive phase input end of the comparator is connected with the current sensing unit, the negative phase input end of the comparator is used as a feedback signal input end of the driving unit, the output end of the comparator is connected with the pulse width modulator, and the pulse width modulator is respectively connected with the control electrode of the input transistor and the control electrode of the output transistor.
10. A DC-DC chip comprising the buck circuit of any one of claims 1-9.
CN202310601970.6A 2023-05-26 2023-05-26 Buck circuit and DC-DC chip Active CN116345908B (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101262174A (en) * 2007-03-09 2008-09-10 凹凸科技（中国）有限公司 DC/DC converter and conversion method
US20100019749A1 (en) * 2008-07-28 2010-01-28 Texas Instruments Incorporated Switching power supply device
CN105356734A (en) * 2015-11-18 2016-02-24 浙江大学 COT-control-based ripple-compensation-based buck circuit power management chip
KR101855339B1 (en) * 2016-11-25 2018-05-08 주식회사 지니틱스 DC-DC converter having a device to cope with change of input voltage
US20180331618A1 (en) * 2017-05-09 2018-11-15 Linear Technology Holding Llc Predictive ripple-cancelling signal into error amplifier of switch mode power supply
CN115459564A (en) * 2022-10-09 2022-12-09 杭州艾诺半导体有限公司 Control circuit of switch converter and switch converter

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101262174A (en) * 2007-03-09 2008-09-10 凹凸科技（中国）有限公司 DC/DC converter and conversion method
US20100019749A1 (en) * 2008-07-28 2010-01-28 Texas Instruments Incorporated Switching power supply device
CN105356734A (en) * 2015-11-18 2016-02-24 浙江大学 COT-control-based ripple-compensation-based buck circuit power management chip
KR101855339B1 (en) * 2016-11-25 2018-05-08 주식회사 지니틱스 DC-DC converter having a device to cope with change of input voltage
US20180331618A1 (en) * 2017-05-09 2018-11-15 Linear Technology Holding Llc Predictive ripple-cancelling signal into error amplifier of switch mode power supply
CN115459564A (en) * 2022-10-09 2022-12-09 杭州艾诺半导体有限公司 Control circuit of switch converter and switch converter

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