DC-DC converters, control methods, switching power supplies, chips and electronic devices

Abstract

This application relates to the field of electronic technology, and in particular to a DC-DC converter, a control method, a switching power supply, a chip, and an electronic device. The DC-DC converter includes a power circuit and a control circuit. The control circuit includes a detection module and a control module. The detection module performs voltage hysteresis on the inductor current sampling signal when it detects that the inductor current sampling signal has reached the critical voltage of a first control mode and a second control mode. By delaying the inductor current sampling signal, the frequency of switching between the first and second control modes at the critical state is reduced, achieving smooth switching of control modes, reducing output voltage ripple, and improving the performance of the power circuit.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and more specifically to a DC-DC converter, a control method, a switching power supply, a chip, and an electronic device. Background Technology

[0002] With the rapid development of microelectronics technology, the requirements for the stability of DC-DC converters (such as boost circuits and buck circuits) are becoming increasingly stringent. A DC-DC converter can include a power circuit and a control circuit. The power circuit outputs a voltage based on the input power supply voltage, while the control circuit controls the switching states of the switching devices in the power circuit using voltage level signals.

[0003] In a DC-DC converter, two control modes for switching devices can be included: a constant on-time (COT) control mode when the power circuit is under heavy load and a pulse width modulation (PWM) control mode when the power circuit is operating normally.

[0004] However, when switching between COT control mode and PWM control mode, the frequency of COT mode is different from that of the clock signal. It is necessary to convert the frequency of COT mode to that of the clock signal. The mode switching point is not precise enough, causing back-and-forth switching at the mode switching threshold, resulting in unstable output voltage of the power circuit. Summary of the Invention

[0005] To address the issue of unstable output voltage in the power circuit caused by switching between the aforementioned modes, embodiments of this application provide a DC-DC converter, a control method, a switching power supply, a chip, and an electronic device.

[0006] In a first aspect, this application provides a DC-DC converter, including a power circuit and a control circuit, wherein the control circuit includes a detection module and a control module.

[0007] The detection module is used for:

[0008] When the inductor current sampling signal in the power circuit starts to exceed the first reference voltage, or when the inductor current sampling signal starts to exceed the second reference voltage, voltage hysteresis processing is applied to the inductor current sampling signal.

[0009] When it is determined that the hysteresis inductor current sampling signal is greater than the first reference voltage, a first trigger signal is output to the control module. When it is determined that the hysteresis inductor current sampling signal is greater than the second reference voltage, a second trigger signal is output to the control module. The first trigger signal corresponds to the first control mode, and the second trigger signal corresponds to the second control mode.

[0010] The control module is used for:

[0011] Receive the first trigger signal or the second trigger signal.

[0012] It is understood that in this application, when the detection module detects that the inductor current sampling signal has reached the critical voltage of the first control mode and the second control mode, it will apply voltage hysteresis to the inductor current sampling signal. By using the hysteresisd inductor current sampling signal, the control mode is avoided from being switched directly at the critical voltage, thereby reducing the frequency of switching between the first control mode and the second control mode in the critical state, realizing smooth switching of control mode, reducing output voltage ripple, and improving the performance of the power circuit.

[0013] In one possible implementation of the first aspect above, the control module is configured to:

[0014] If the first trigger signal is received in the second control mode, a first level signal is output in the next cycle corresponding to the second control mode to control the switch of the power circuit to discharge within a preset time.

[0015] If multiple second trigger signals are received consecutively in the first control mode, a second level signal is output to control the power circuit to charge and discharge at a fixed frequency.

[0016] It is understandable that in the second control mode, when the first trigger signal is received, the control module enters the first control mode in the next cycle, and when multiple second trigger signals are received in the first control mode, the control mode enters the second control mode. The periodic delay in the switching of control modes can also reduce the frequency of switching between the first and second control modes in the critical state, making the switching of control modes smoother.

[0017] In one possible implementation of the first aspect above, the first control mode is a COT control mode, and the second control mode is a PWM control mode.

[0018] In one possible implementation of the first aspect above, the detection module includes a hysteresis unit, a first detection unit, and a second detection unit;

[0019] One end of the hysteresis unit is connected to the first end of the inductor of the power circuit, and the other end of the hysteresis unit is connected to the control module. The hysteresis unit is also connected to the first detection unit and the second detection unit.

[0020] The hysteresis unit is used to: output a hysteresis-restricted inductor current sampling signal to the first detection unit and the second detection unit 3 when it is detected that the inductor current sampling signal starts to be greater than the first reference voltage or the inductor current sampling signal starts to be greater than the second reference voltage;

[0021] The first detection unit is connected to the control module, and the first detection unit is used for:

[0022] When the hysteresis inductor current sampling signal is detected to be greater than the first reference voltage, a first trigger signal is output to the control module.

[0023] The second detection unit is connected to the control module, and the second detection unit is used for:

[0024] When the hysteresis inductor current sampling signal is detected to be greater than the second reference voltage, a second trigger signal is output to the control module.

[0025] In one possible implementation of the first aspect above, the detection module includes a hysteresis unit, a first detection unit, and a second detection unit;

[0026] The first detection unit is connected to the inductor and the control module, and the first detection unit is used for:

[0027] When the inductor current sampling signal is detected to be greater than the first reference voltage, a first trigger signal is output to the control module;

[0028] The second detection unit is connected to the hysteresis unit and the control module, and the second detection unit is used for:

[0029] When the sum of the inductor current sampling signal and the voltage of the hysteresis unit is detected to be greater than the second reference voltage, a second trigger signal is output to the control module;

[0030] One end of the hysteresis unit is connected to the first terminal of the inductor of the power circuit, and the other end of the hysteresis unit is connected to the control module. The hysteresis unit is also connected to the second detection unit. The hysteresis unit is used for:

[0031] The hysteresis voltage input to the first detection unit is changed according to the control of the control module.

[0032] In one possible implementation of the first aspect described above, the hysteresis unit includes a hysteresis voltage generation subunit and a first switch;

[0033] The first terminal of the first switch is connected to the hysteresis voltage generation subunit, the second terminal of the first switch is connected to the control module, and the third terminal of the first switch is connected to the second detection unit.

[0034] The hysteresis voltage generation subunit is used to: generate a preset hysteresis voltage;

[0035] The control module is used for:

[0036] In the first control mode, the circuit connecting the first switch between the hysteresis voltage generation subunit and the second detection unit is in a conducting state, and the hysteresis voltage is the preset hysteresis voltage.

[0037] When the control module receives the second trigger signal, it controls the circuit between the first switch and the hysteresis voltage generation subunit and the second detection unit to be disconnected, and the hysteresis voltage is zero.

[0038] In one possible implementation of the first aspect described above, the first switch includes a single-pole double-throw switch.

[0039] It is understood that in some embodiments, the first switch can be a metal-oxide-semiconductor field-effect transistor (MOS), a transmission gate, etc., and this application does not limit this.

[0040] In one possible implementation of the first aspect above, the first detection unit includes a first sampling subunit and a first comparator, and the second detection unit includes a second sampling subunit, a second comparator, and an operational amplifier;

[0041] The first end of the first sampling subunit is connected to the first end of the inductor, and the other end of the first sampling subunit is connected to the first input terminal of the first comparator. The first sampling subunit is used to sample the inductor current with a first sampling coefficient and output the corresponding first voltage value.

[0042] The second input terminal of the first comparator is connected to the first reference voltage, and the first comparator is used to compare the first voltage value output by the first sampling subunit with the magnitude of the first reference voltage;

[0043] The first end of the second sampling subunit is connected to the first end of the inductor, and the other end of the second sampling subunit is connected to the first input terminal of the second comparator. The second sampling subunit is used to sample the inductor current with a second sampling coefficient and output the corresponding voltage value.

[0044] The third terminal of the first switch is connected to the first input terminal of the second comparator;

[0045] The first input terminal of the operational amplifier is connected to the second reference voltage, the first input terminal of the operational amplifier is connected to the output node of the power circuit, and the output terminal of the operational amplifier is connected to the second input terminal of the second comparator.

[0046] The operational amplifier is used for:

[0047] The voltage difference between the output voltage of the power circuit and the second reference voltage is amplified, and the amplified voltage difference is output to the second input terminal of the second comparator.

[0048] The output of the second comparator is connected to the control module. The second comparator is used to compare the sum of the voltage value output by the second sampling subunit and the voltage output by the first switch with the amplified voltage difference output by the operational amplifier.

[0049] In one possible implementation of the first aspect above, the second detection unit may further include a ramp voltage generating subunit, which is connected to the first input terminal of the second comparator;

[0050] The ramp voltage generation subunit is used to generate a voltage with a certain slope, which is superimposed on the voltage value output by the second sampling subunit to perform ramp compensation on the inductor current.

[0051] In one possible implementation of the first aspect described above, the control module is further configured to:

[0052] Generate a single-cycle signal that is synchronized with the clock signal corresponding to the second control mode. The period of the single-cycle signal includes a first preset time period and a second preset time period.

[0053] When the control module is in the first control mode and the control module receives the second trigger signal:

[0054] If the control module receives the first trigger signal within the first preset time period of the single-cycle signal, the control module controls the inductor of the power circuit to discharge during the remaining period of the single-cycle signal.

[0055] If the control module does not receive the first trigger signal within the first preset time period of the single-cycle signal, the control module controls the inductor of the power circuit to charge within the first preset time period of the single-cycle signal and discharge within the second preset time period.

[0056] In one possible implementation of the first aspect above, the control module includes a mode switching unit and a drive unit;

[0057] One side of the mode switching unit is connected to the output terminals of the first comparator and the second comparator, and the other side of the mode switching unit is connected to one side of the driving unit. The mode switching unit is used to generate the first level signal according to the first trigger signal output by the first comparator, or to output a second level signal to the driving unit according to the second trigger signal output by the second comparator.

[0058] The other side of the drive unit is connected to the control terminals of the first power switch and the second power switch in the power circuit, respectively, and is used to control the on / off state of the first power switch and the second power switch based on the first level signal or the second level signal, so as to control the charging and discharging of the inductor in the power circuit.

[0059] In one possible implementation of the first aspect described above, the control module further includes a latch connected between the mode switching unit and the drive unit, the latch being used to convert the pulse signal output by the mode switching unit into the first level signal or the second level signal.

[0060] In one possible implementation of the first aspect described above, the control circuit further includes a fixed on-time module;

[0061] One side of the fixed on-time module is connected to the input node and the output node of the power circuit, and the other side of the fixed on-time module is connected to the control module.

[0062] The fixed on-time module is used to: output a first level signal of the preset time to the control module based on the detected input voltage and output voltage of the power circuit;

[0063] The control module is used to output a first level signal for the preset time when it receives the first trigger signal.

[0064] In one possible implementation of the first aspect described above, the control circuit further includes a duty cycle detection module;

[0065] The duty cycle detection module is connected to the output node of the power circuit and one side of the fixed on-time module. The duty cycle detection module is used to detect the output voltage of the power circuit, and when the output voltage is detected to be greater than the third reference voltage, it outputs a frequency control signal to the fixed on-time module.

[0066] The fixed on-time module is used for:

[0067] Upon receiving the frequency control signal, the preset time is adjusted based on the frequency control signal, and a first level signal of the adjusted preset time is output.

[0068] In one possible implementation of the first aspect described above, the duty cycle detection module 124 includes a third comparator;

[0069] The first input terminal of the third comparator is connected to the third reference voltage, and the second input terminal of the third comparator is connected to the output node of the power circuit.

[0070] The third comparator is used for:

[0071] The output voltage of the power circuit is compared with the magnitude of the third reference voltage, and the frequency control signal is output based on the comparison result.

[0072] In one possible implementation of the first aspect above, the fixed on-time module includes a fourth comparator, an on-resistor, a variable resistor, an on-capacitor, and a voltage-to-current converter.

[0073] One end of the voltage-to-current converter is connected to the output node of the power circuit, and the other end of the voltage-to-current converter is connected to the first terminal of the conducting capacitor. The voltage-to-current converter is used to convert the detected output voltage of the power circuit into current, and the current output by the voltage-to-current converter is used to charge the conducting capacitor.

[0074] The first end of the conducting capacitor is connected to the first input terminal of the fourth comparator, and the second end of the conducting capacitor is grounded.

[0075] The first end of the on-resistor is connected to the input node of the power circuit, the second end of the on-resistor is connected to the second input terminal of the fourth comparator and one end of the variable resistor, and the other end of the variable resistor is grounded.

[0076] The output of the fourth comparator is connected to the control module.

[0077] In one possible implementation of the first aspect described above, when the variable resistor detects the frequency control signal output by the duty cycle detection circuit, it controls the resistance value of the variable resistor to change the preset time.

[0078] Secondly, this application provides a control method for a DC-DC converter, which is applied to a DC-DC converter, the DC-DC converter including a power circuit and a control circuit, the control circuit including a detection module and a control module;

[0079] The method includes:

[0080] When the detection module detects that the inductor current sampling signal in the power circuit starts to be greater than the first reference voltage, or when the inductor current sampling signal starts to be greater than the second reference voltage, it applies voltage hysteresis to the inductor current sampling signal, and when it determines that the hysteresis inductor current sampling signal is greater than the first reference voltage, it outputs a first trigger signal to the control module, or when it determines that the hysteresis inductor current sampling signal is greater than the second reference voltage, it outputs a second trigger signal to the control module.

[0081] Receive the first trigger signal or the second trigger signal.

[0082] In one possible implementation of the first aspect above, the method further includes:

[0083] If the control module receives the first trigger signal, the control module will output a first level signal in the next cycle corresponding to the second control mode to control the power circuit to discharge within a preset time.

[0084] If the control module receives multiple second trigger signals in the first control mode, the control module outputs a second level signal to control the power circuit to charge and discharge at a fixed frequency.

[0085] Thirdly, this application provides a switching power supply, including the DC converter and DC power supply described in the first aspect and any possible implementation thereof; the DC power supply is connected to the input side of the power circuit.

[0086] Fourthly, this application provides a chip comprising: a DC-DC converter and a DC power supply as described in the first aspect and any possible implementation thereof, wherein the DC-DC converter is used to execute the control method of the DC-DC converter described in the second aspect, and the DC power supply is connected to the input side of the power circuit in the DC-DC converter.

[0087] Fifthly, this application provides an electronic device, comprising: a DC-DC converter and a DC power supply as described in the first aspect and any possible implementation thereof, wherein the DC power supply is connected to the input side of the power circuit in the DC-DC converter;

[0088] A memory for storing instructions executed by one or more processors of the electronic device, and,

[0089] The processor is one of the processors in the electronic device, used to trigger the DC-DC converter to execute the control method of the DC-DC converter described in the second aspect above. Attached Figure Description

[0090] Figure 1a The diagram shown is a schematic of a circuit structure based on a DC-DC converter provided in some embodiments;

[0091] Figure 1b The diagram shown is a schematic of a circuit structure based on a DC-DC converter provided in some embodiments;

[0092] Figure 2 The diagram shown is a schematic diagram of the circuit structure of a control circuit provided in an embodiment of this application;

[0093] Figure 3 The diagram shown is a schematic diagram of the circuit structure of another control circuit provided in an embodiment of this application;

[0094] Figure 4 The diagram shown is a circuit schematic of a DC-DC converter provided in an embodiment of this application.

[0095] Figure 5 The diagram shown is a circuit diagram of a COT module provided in an embodiment of this application;

[0096] Figure 6 The diagram shown is a schematic diagram of the signal waveforms of some nodes in a circuit for entering COT control mode according to an embodiment of this application;

[0097] Figure 7a The diagram shown is a schematic diagram of the signal waveforms of some nodes in a circuit for exiting COT control mode according to an embodiment of this application;

[0098] Figure 7b The diagram shown is a schematic diagram of the signal waveforms of some nodes in another circuit for exiting the COT control mode provided in an embodiment of this application.

[0099] Figure 8 The diagram shown is a schematic diagram of the signal waveforms of some nodes in the circuit for further frequency reduction of the COT module provided in the embodiment of this application;

[0100] Figure 9The diagram shown is a flowchart illustrating a control method for a control circuit according to an embodiment of this application.

[0101] Figure 10 The diagram shown is a flowchart illustrating a control method for another control circuit provided in an embodiment of this application.

[0102] Figure 11 The diagram shown is a schematic diagram of the circuit structure of a switching power supply provided in an embodiment of this application. Detailed Implementation

[0103] The present invention is described below based on embodiments, but the invention is not limited to these embodiments. In the detailed description of the invention below, certain specific details are described in detail. Those skilled in the art will fully understand the invention even without these details. To avoid obscuring the essence of the invention, well-known methods, processes, flows, elements, and circuits are not described in detail.

[0104] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0105] Unless the context explicitly requires it, words such as "including" or "contains" throughout the specification should be interpreted as including rather than exclusive or exhaustive; that is, meaning "including but not limited to".

[0106] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0107] As mentioned earlier, when switching between COT control mode and PWM control mode, the frequency of COT mode is different from that of the clock signal. It is necessary to convert the frequency of COT mode to that of the clock signal. The mode switching point will not be precise enough, causing back-and-forth switching at the mode switching threshold. This will result in unstable output voltage of the power circuit, affecting the normal function of the power circuit load.

[0108] For example, Figure 1aThe DC-DC converter shown includes a power circuit 101 and a control circuit 102. The current sampling module K11 in the control circuit 102 detects the current in the inductor of the power circuit 101 and converts it into a voltage VS2. When the comparator PWM1 determines that the voltage VS2 is greater than a preset voltage, it indicates that the power circuit 101 is overloaded, and outputs a first trigger signal to the mode control module 104. Upon receiving the first trigger signal, the mode control module 104 outputs a pulse signal for a preset time, and the RS latch converts the pulse signal into a first level signal. The drive module 105 drives the switch in the power circuit 101 according to the first level signal, causing the inductor to discharge within a preset time. At this time, the control mode of the control circuit 102 is COT mode, and the inductor in the power circuit 101 discharges within the preset time. The preset voltage of the comparator PWM1 is obtained by amplifying the difference between the output voltage of the power circuit 101 and the preset output voltage V1 by the error amplifier EA.

[0109] When the current sampling module K12 in the control circuit 102 detects the current in the inductor of the power circuit 101, it converts it into a voltage VS1. When the comparator PEAK1 determines that voltage VS1 is greater than the reference voltage V2, it indicates that the power circuit 101 has not reached its overload and is operating normally. Therefore, it outputs a second trigger signal to the mode control module 104. Upon receiving the second trigger signal, the mode control module 104 outputs a pulse signal, and the RS latch converts the pulse signal into a second-level signal. The drive module 105 drives the switch in the power circuit 101 according to the second-level signal, causing the inductor to charge and discharge at a fixed frequency. At this time, the control mode of the mode control module 104 is PWM control mode.

[0110] In the above Figure 1a In the DC-DC converter shown, the output voltage of the power circuit 101 is not a stable and clean DC voltage due to noise and other interference, but fluctuates, i.e., voltage ripple. When switching between COT control mode and PWM control mode, the control circuit 102 is prone to switching back and forth between the two modes at the critical point of switching. The output voltage ripple of the power circuit 101 becomes larger and unstable, affecting the circuit performance of the power circuit.

[0111] To address the problem of increased and unstable output voltage ripple in the power circuit caused by the frequent switching of control circuit modes, this application provides a DC-DC converter including a power circuit and a control circuit. Specifically, the control circuit includes a current detection module and a control module. The detection module applies voltage hysteresis to the inductor current sampling signal when it detects that the inductor current sampling signal in the power circuit begins to exceed a first reference voltage, or when it detects that the inductor current sampling signal begins to exceed a second reference voltage. Upon determining that the hysteresis-restricted inductor current sampling signal exceeds the first reference voltage, the detection module outputs a first trigger signal to the control module. Upon determining that the hysteresis-restricted inductor current sampling signal exceeds the second reference voltage, the detection module outputs a second trigger signal to the control module. The first trigger signal corresponds to a first control mode (e.g., COT control mode), and the second trigger signal corresponds to a second control mode (e.g., PWM control mode). If the control module receives the first trigger signal in the second control mode, it outputs a first-level signal in the next cycle corresponding to the second control mode, controlling the power circuit switch to discharge within a preset time. If the control module continuously receives multiple second trigger signals in the first control mode, it outputs a second-level signal, controlling the power circuit switch to charge and discharge at a fixed frequency. The second reference voltage is related to the output voltage of the power circuit.

[0112] It can be understood that the inductor current sampling signal is a signal obtained by sampling the inductor current and converting it into voltage and current, and it is represented as a voltage value.

[0113] It is understood that in this embodiment of the application, when the detection module detects that the inductor current sampling signal reaches the critical voltage of the first control mode and the second control mode, it will hysteresis the inductor current sampling signal. By hysteresis the inductor current sampling signal, the frequency of switching back and forth between the first control mode and the second control mode at the critical state is reduced, thus realizing smooth switching of control modes, reducing output voltage ripple, and improving the performance of the power circuit.

[0114] Furthermore, in the second control mode, when the first trigger signal is received, the control module enters the first control mode in the next cycle. In the first control mode, when multiple second trigger signals are received consecutively, the control mode enters the second control mode. The periodic delay in switching control modes can also reduce the frequency of switching between the first and second control modes in critical states, making the switching of control modes smoother.

[0115] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0116] The following is combined with Figure 1bThis application provides a detailed description of a DC-DC converter according to an embodiment.

[0117] like Figure 1b As shown, the DC-DC converter includes a power circuit 110 and a control circuit 120. The control circuit 120 includes a detection module 121 and a control module 122.

[0118] The detection module 121 is connected to one end of the inductor of the power circuit 110, and the other end of the detection module 121 is connected to the control module 122. The detection module 121 is used to: perform voltage hysteresis on the inductor current sampling signal VL when it detects that the inductor current sampling signal VL in the power circuit 110 starts to be greater than the first reference voltage VREF1, or when the inductor current sampling signal VL starts to be less than the second reference voltage VREF2; and output a first trigger signal to the control module 122 when it is determined that the hysteresis inductor current sampling signal is greater than the first reference voltage VREF1; and output a second trigger signal to the control module 122 when it is determined that the hysteresis inductor current sampling signal is greater than the second reference voltage VREF2. The first trigger signal corresponds to a first control mode (e.g., COT control mode), and the second trigger signal corresponds to a second control mode (e.g., PWM control mode).

[0119] The other end of the control module 122 is connected to switches M1 and M2 of the power circuit 110, and is used for: if the control module 122 receives a first trigger signal in the second control mode, it outputs a first level signal in the next cycle corresponding to the second control mode to drive switches M1 and M2 of the power circuit 110, so as to control the inductor L in the power circuit 110 to charge and discharge within a fixed time; if the control module 122 receives multiple second trigger signals consecutively in the first control mode, it outputs a second level signal to drive switches M1 and M2 of the power circuit 110, so as to control the inductor L in the power circuit 110 to charge and discharge at a fixed frequency. The second reference voltage is related to the output voltage VO of the power circuit 110.

[0120] Taking a pseudo-fixed frequency control mode as the first control mode and a PWM control mode as the second control mode as an example, it can be understood that when the detection module 121 detects that the inductor current sampling signal VL in the power circuit 110 starts to be greater than the first reference voltage VREF1, it indicates that the power circuit 110 is in a high load state, and the control mode needs to be switched from the PWM control mode to the pseudo-fixed frequency control mode. When it detects that the inductor current sampling signal VL starts to be greater than the second reference voltage VREF2, it indicates that the power circuit 110 is not in a high load state, and the control mode needs to be switched from the COT control mode to the PWM control mode, that is, a control mode switch needs to occur. At this time, the detection module 121 can perform voltage hysteresis on the inductor current sampling signal VL and determine the relationship between the hysteresis inductor current sampling signal VL' and the first and second reference voltages to generate a first trigger signal or a second trigger signal. That is, the detection module 121 performs voltage hysteresis.

[0121] It is understandable that when the control module 122 receives the first or second trigger signal obtained after the voltage hysteresis of the detection module 121, it does not immediately switch between the first and second level signals. In COT control mode, the control module 122 only switches to PWM control mode and triggers the output of the second level signal after detecting multiple second trigger signals; in PWM control mode, detecting the first trigger signal will switch to COT control mode in the next cycle and trigger the output of the first level signal, i.e., the control module 122 performs periodic hysteresis.

[0122] Furthermore, the DC-DC converter provided in this application reduces the frequency of switching between the first and second control modes at critical states by using the voltage hysteresis of the detection module and the periodic hysteresis of the control module in the control circuit, thereby achieving smooth switching of control modes, reducing output voltage ripple, and improving the performance of the power circuit.

[0123] It should be noted that the trigger signal provided in this application embodiment can be a pulse signal. The first level signal with a preset time provided in this application embodiment can be a high level signal with a preset time or a low level signal with a preset time; this application embodiment does not limit this.

[0124] It can be understood that when the first level signal is a high level signal, the high level signal is maintained for a preset time within one cycle. When the first level signal is a low level signal, the low level signal is maintained for a preset time within one cycle.

[0125] like Figure 2 As shown, in some embodiments, the detection module 121 may include a hysteresis unit 201, a first detection unit 202, and a second detection unit 203.

[0126] The hysteresis unit 201 can be connected to the first detection unit 202 and the second detection unit 203 to hysteresis the inductor current sampling signal VL input to the first detection unit 202 and the second detection unit 203.

[0127] Specifically, one end of the hysteresis unit 201 is connected to one end of the inductor L, and the other end of the hysteresis unit 201 is connected to the control module 122. The hysteresis unit 201 is also connected to the first detection unit 202 and the second detection unit 203. The hysteresis unit 201 is used to output a hysteresis-reduced inductor current sampling signal VL' to the first detection unit 202 and the second detection unit 203 when it detects that the inductor current sampling signal VL starts to be greater than the first reference voltage VREF1 or the inductor current sampling signal VL starts to be greater than the second reference voltage VREF2.

[0128] The first detection unit 202 is connected to the control module 122. The first detection unit 201 is used to output a first trigger signal to the control module 122 when it detects that the hysteresis inductor current sampling signal VL' is greater than the first reference voltage VREF1.

[0129] The second detection unit 202 is connected to the control module 122. The second detection unit 202 is used to output a second trigger signal to the control module 122 when it detects that the hysteresis inductor current sampling signal VL' is greater than the second reference voltage VREF2.

[0130] like Figure 3 As shown, in some other embodiments, the hysteresis unit 201 may be connected to the first detection unit 202 or the second detection unit 203, and the hysteresis unit 202 may change the magnitude of the generated hysteresis voltage based on the control of the control module 122, so as to sample the inductor current signal VL input to the first detection unit 202 or the second detection unit 203.

[0131] Specifically, taking the hysteresis unit 201 connected to the second detection unit 203 as an example. One end of the second detection unit 203 is connected to the inductor L, and the other end of the second detection unit 203 is connected to the control module 122.

[0132] Hysteresis unit 201 may include a hysteresis voltage generation subunit (e.g. Figure 3 The first terminal of the first switch S1 is connected to the hysteresis voltage generation subunit, the second terminal of the first switch S1 is connected to the control module 122, and the third terminal of the first switch S1 is connected to the second detection unit 203.

[0133] It is understood that the first switch S1 can be a single-pole double-throw switch, a field-effect transistor, or a transmission gate, etc., where the transistor can be, for example, a P-type metal-oxide-semiconductor field-effect transistor (PMOS).

[0134] In some embodiments, the first switch S1 is a single-pole double-throw switch. Then: in the first control mode, the connection between the first switch S1 and the hysteresis voltage generation subunit and the second detection unit 203 is closed, and the inductor current sampling signal input to the second detection unit 203 is the hysteresis-enhanced inductor current sampling signal with hysteresis voltage VDC applied. When the second detection unit 203 detects that the hysteresis-enhanced inductor current sampling signal received by the control module 122 is less than the second reference voltage, the second detection unit 203 outputs a second trigger signal to the control module 122. Upon receiving the second trigger signal, the control module 122 controls the first switch S1 to switch, that is, controls the connection between the first switch S1 and the control module 122 and the second detection unit 203 to be closed, and the inductor current sampling signal input to the second detection unit 203 is the inductor current sampling signal without hysteresis voltage VDC applied.

[0135] In other embodiments, the first switch S1 is a PMOS transistor, and the hysteresis control signal output by the control module 122 can control the on / off state of the first switch S1. Specifically, the control module 122 is connected to the control terminal of the first switch S1, the hysteresis voltage generation subunit is connected to the first terminal of the first switch S1, and the second detection unit 203 is connected to the second terminal of the first switch S1.

[0136] When the control module 122 is in the first control mode, the first switch S1 is turned on, and the inductor current sampling signal input to the second detection unit 203 is the inductor current sampling signal after hysteresis with hysteresis voltage VDC applied. When the second detection unit 203 detects that the inductor current sampling signal received by the control module 122 after hysteresis is less than the second reference voltage, the second detection unit 203 outputs a second trigger signal to the control module 122. When the control module 122 receives the second trigger signal, it controls the first switch S1 to turn off, and the inductor current sampling signal input to the second detection unit 203 is the inductor current sampling signal without hysteresis voltage VDC applied.

[0137] It is understood that in some embodiments, the hysteresis unit 201 may include more or fewer devices than described above, and this application does not limit this.

[0138] like Figure 4As shown, in some embodiments, the first detection unit 202 may include a first sampling subunit K21 and a first comparator PEAK2. The second detection unit 203 includes a second sampling subunit K22, a second comparator PWM2, and an operational amplifier EA2.

[0139] The first sampling subunit K21 is connected to the first pole of switch M1, and the other end of the first sampling subunit K21 is connected to the first input terminal of the first comparator PEAK2. The first sampling subunit K21 can sample the inductor current with a first sampling coefficient k21 and output the corresponding first voltage value VSENSE1.

[0140] The second input terminal of the first comparator PEAK2 is connected to the first reference voltage VREF1. The first comparator PEAK2 is used to compare the first voltage value VSENSE1 output by the first sampling subunit K21 with the first reference voltage VREF1.

[0141] In some embodiments, the first input terminal of the first comparator PEAK2 is a positive input terminal and the second input terminal is a negative input terminal. When the first comparator PEAK2 determines that the first voltage value VSENSE1 is greater than the first reference voltage VREF1, it outputs a first trigger signal.

[0142] The first end of the second sampling subunit K22 is connected to the first stage of switch M1, and the other end of the second sampling subunit K22 is connected to the first input terminal of the second comparator PWM2. The second sampling subunit K22 can sample the inductor current with the second sampling coefficient K22 and output the corresponding voltage value.

[0143] The third terminal of the first switch S1 is connected to the first input terminal of the second comparator PWM2.

[0144] The first input terminal of operational amplifier EA2 is connected to the second reference voltage VREF2, and the first input terminal of operational amplifier EA2 is connected to the output terminal of power circuit 110. The output terminal of operational amplifier EA2 is connected to the second input terminal of second comparator PWM2. Operational amplifier EA2 is used to amplify the voltage difference between the output voltage VO of power circuit 110 and the second reference voltage VREF2, and output the amplified voltage difference to the second input terminal of second comparator PWM2.

[0145] The output of the second comparator PWM2 is connected to the control module 122. The second comparator PWM2 is used to compare the sum of the voltage value output by the second sampling subunit K22 and the voltage output by the first switch S1, VSENSE2, with the amplified voltage difference output by the operational amplifier EA2.

[0146] In some embodiments, the first input terminal of the second comparator PWM2 is a positive input terminal and the second input terminal is a negative input terminal. When the second comparator PWM2 determines that the sum of the voltage value output by the second sampling subunit K22 and the voltage output by the first switch S1, VSENSE2, is greater than the amplified voltage difference, it outputs a second trigger signal.

[0147] Understandable, Figure 4 In the DC-DC converter shown, when the control circuit 120 starts working, if the first comparator PEAK2 outputs the first trigger signal first, the control circuit 120 enters the first control mode (e.g., COT control mode). If the second comparator PWM2 outputs the second trigger signal first, the control circuit 120 enters the second control mode (e.g., PWM control mode). While the control circuit 120 is operating, it can further determine whether a trigger signal for another control mode has been received, and perform hysteresis operations such as periodic hysteresis or voltage hysteresis to complete the mode switching.

[0148] In some embodiments, the second detection unit 203 may further include a slope voltage generation subunit Vslope2, which is connected to the first input terminal of the second comparator PWM2. The slope voltage generation subunit Vslope2 generates a voltage with a certain slope (hereinafter referred to as slope voltage), which is superimposed on the voltage value output by the second sampling subunit K22 to perform slope compensation on the DC-DC converter.

[0149] Furthermore, the second comparator PWM2 can be used to compare the sum of the voltage value output by the second sampling subunit K22, the ramp voltage generated by the ramp voltage generation subunit Vslope2, and the voltage output by the first switch S1, VSENSE2, with the amplified voltage output by the operational amplifier EA2.

[0150] In some embodiments, the control module 122 may also generate a single-cycle signal EN synchronized with the clock signal CLK corresponding to the second control mode, and the period T of the single-cycle signal EN includes a first preset time period DT and a second preset time period T-DT. When the control module 122 is in the first control mode and receives the second trigger signal, if the control module 122 receives the first trigger signal within the first preset time period DT of the period T of the single-cycle signal EN, the control module 122 controls the inductor of the power circuit 110 to discharge during the remaining period of the single-cycle signal EN; if the control module 122 does not receive the first trigger signal within the first preset time period DT of the period T of the single-cycle signal EN, the control module 122 controls the inductor of the power circuit 110 to charge during the first preset time period DT of the single-cycle signal EN and discharge during the second preset time period T-DT. This will be explained in detail below with reference to the signal waveform diagrams corresponding to the key nodes of the control circuit 120.

[0151] refer to Figure 4 As shown, in some embodiments, the control module 122 may include a mode switching unit MODE CTRL and a drive unit DRIVER.

[0152] The mode switching unit MODE CTRL is connected to the outputs of the first comparator PEAK2 and the second comparator PWM2 on one side, and to the drive unit DRIVER on the other side. The mode switching unit MODE CTRL is used to generate a first level signal based on the first trigger signal output by the first comparator PEAK2, or to output a second level signal to the drive unit DRIVER based on the second trigger signal output by the second comparator PWM2.

[0153] The other side of the drive unit DRIVER is connected to the control terminals of switches M1 and M2 in the power circuit 110, respectively, and is used to control the on and off of switches M1 and M2 based on the first level signal or the second level signal, thereby controlling the inductor L to charge and discharge.

[0154] In some embodiments, the signal output by the mode switching unit MODE CTRL is a pulse signal, and the control module 122 may further include a latch connected between the mode switching unit MODE CTRL and the drive unit DRIVER, for example... Figure 4 RS latch RS_Q in the middle.

[0155] The latch RS_Q can convert the pulse signal output by the mode switching unit MODE CTRL into a level signal and output a level signal (including a first level signal and a second level signal) to the drive unit DRIVER, so that the drive unit DRIVER can control the on / off state of switches M1 and M2 based on the first level signal or the second level signal, thereby controlling the charging and discharging of inductor L.

[0156] Continue to refer to Figure 4 The control circuit 120 in the DC-DC converter may further include a COT module 123. One side of the COT module 123 is connected to the input and output terminals of the power circuit 110, and the other side of the COT module 123 is connected to the control module 122. The COT module 123 is used to output a first-level signal for a preset time (i.e., a turn-off time) based on the detected input voltage VI and output voltage VO of the power circuit 110. The control module 122 is used to output a first-level signal for the preset time received when a first trigger signal is received.

[0157] It is understood that the switching frequency of the switches (switches M1 and M2) in the power circuit 110 changes with the duty cycle of the output voltage of the power circuit 110. Specifically, the smaller the duty cycle of the output voltage, the faster the switching frequency. The increase in the switching frequency will increase the switching losses of the power circuit 110, cause severe heat generation in the DC-DC converter chip, and reduce efficiency. Considering that the duty cycle of the output voltage is related to the input voltage VI and the output voltage VO of the power circuit 110, in this embodiment, the control circuit 120 can adjust the preset time based on the detected input voltage VI and output voltage VO, that is, adjust the frequency of the first level signal output by the COT module 123, so that in the first control mode, the switching frequency of the switches in the power circuit 110 is maintained at a stable frequency without large fluctuations, and the operating efficiency of the power circuit 110 remains unchanged.

[0158] In some embodiments, the control circuit 120 further includes a duty cycle detection module 124. The duty cycle detection module 124 is connected to the output terminal of the power circuit 110 and one side of the COT module 123, detects the output voltage VO at the output terminal, and outputs a frequency control signal to the COT module 123 when the output voltage VO is detected to be greater than the third reference voltage.

[0159] When the COT module 123 receives the frequency control signal, it can adjust the preset time based on the frequency control signal and output the first level signal of the adjusted preset time.

[0160] It is understandable that the duty cycle detection module 124 detects that the output voltage VO is greater than the third reference voltage, indicating that the duty cycle of the power circuit's output voltage is too small. Since the control circuit 120's control of the power circuit 110 will have a delay, if the duty cycle is too small, the power circuit 110 may charge before the inductor begins to discharge, affecting the performance of the power circuit 110. In this embodiment, when the duty cycle of the output voltage is detected to be too small, the preset time of the COT module 123 is adjusted by the frequency control signal output by the duty cycle detection module 124. Specifically, the COT module 123 can reduce its operating frequency using the frequency control signal to increase the duty cycle of the output voltage. When the duty cycle of the output voltage is normal, the preset time of the COT module 123 is adjusted by the frequency control signal output by the duty cycle detection module 124. Specifically, the COT module 123 can restore its operating frequency using the frequency control signal to restore the duty cycle of the output voltage.

[0161] like Figure 4As shown, in some embodiments, the duty cycle detection module 124 includes a third comparator D_DET. The first input terminal of the third comparator D_DET is connected to the third reference voltage VREF3, and the second input terminal of the third comparator D_DET is connected to the output node of the power circuit 110. The third comparator D_DET is used to determine the magnitude of the output voltage of the power circuit 110 and the third reference voltage VREF3, and outputs a frequency control signal based on the determination result.

[0162] In some embodiments, the first input terminal of the third comparator D_DET is a positive input terminal, and the second input terminal of the third comparator D_DET is a negative input terminal. The comparator outputs a high level when it determines that the output voltage VO of the power circuit 110 is less than the third reference voltage VREF3, and outputs a low level when it determines that the output voltage VO of the power circuit 110 is greater than or equal to the third reference voltage VREF3. In other embodiments, the first input terminal of the third comparator D_DET can be a negative input terminal, and the second input terminal of the third comparator D_DET can be a positive input terminal; this application does not impose any limitations on this.

[0163] Figure 5 The diagram shown is a circuit diagram of a COT module provided in an embodiment of this application.

[0164] like Figure 5 As shown, the COT module 123 may include a fourth comparator TOFF, an on-resistor R1231, a variable resistor R1232, an on-capacitor C123, and a voltage-to-current converter I / V.

[0165] One end of the voltage-to-current converter I / V is connected to the output node of the power circuit, and the other end of the voltage-to-current converter I / V is connected to the first end of the conducting capacitor C123. The voltage-to-current converter I / V is used to convert the detected output voltage VO of the power circuit into current.

[0166] The first terminal of the conducting capacitor C123 is also connected to the first input terminal of the fourth comparator TOFF, and the second terminal of the conducting capacitor C123 is grounded.

[0167] The first terminal of the on-resistor R1231 is connected to the input node of the power circuit, and the second terminal of the on-resistor R1231 is connected to the second input terminal of the fourth comparator TOFF and one terminal of the variable resistor R1232. The other terminal of the variable resistor R1232 is grounded.

[0168] The output of the fourth comparator TOFF is connected to the control module 122.

[0169] As can be understood, taking the first input terminal of the fourth comparator TOFF as the positive input terminal and the second input terminal as the negative input terminal as an example, the working principle of the COT module 123 is as follows: The current output from the voltage-to-current converter I / V is used to charge the conducting capacitor C123. When the voltage of the conducting capacitor C123 increases and is greater than the voltage of the negative input terminal of the fourth comparator TOFF, the fourth comparator TOFF can output a high-level signal. When the conducting capacitor C123 saturates and begins to discharge, the voltage of the conducting capacitor C123 decreases. When the voltage of the conducting capacitor C123 is less than the voltage of the negative input terminal, the fourth comparator TOFF can output a low-level signal. The duration of the high-level signal is a preset time, which is positively correlated with the input voltage VI and the output voltage VO.

[0170] In some embodiments, when the COT module 123 receives a high-level signal from the third comparator D_DET that indicates a decrease in the duty cycle, the variable resistor R1232 can lower its resistance value based on the frequency control signal. The voltage at the negative input terminal of the fourth comparator TOFF decreases, the duration of the high-level signal of the fourth comparator TOFF increases, and the frequency of the first level signal decreases.

[0171] The following uses the first control mode as the COT control mode and the second control mode as the PWM control mode, combined with... Figure 4 The waveform diagram of the output signal of some nodes in the circuit diagram shown illustrates the beneficial effects of this application. It can be understood that the horizontal axis of the waveform diagram represents time, and the vertical axis represents the corresponding voltage or current value.

[0172] First, combined Figure 6 The following describes the signal waveforms of some nodes that switch from PWM control mode to COT control mode in the embodiments of this application.

[0173] Understandable. Figure 6 In the waveforms, CLK corresponds to the system clock signal, specifically the clock signal of the input mode switching unit MODE CTRL. IL corresponds to the current signal of inductor L. PEAK2 corresponds to the output signal of the first comparator PEAK2. PWM2 corresponds to the output signal of the second comparator PWM2. VO corresponds to the output voltage signal of the power circuit 110 output node. COT_MODE corresponds to the COT control mode waveform; when high, it indicates that the control circuit 120 is in COT control mode. VSENSE2 corresponds to the positive input signal of the second comparator PWM2.

[0174] Depend on Figure 6It can be seen that in PWM control mode, i.e. when COT_MODE is low, the frequency of the output voltage VO and the inductor current IL are synchronized with the clock signal CLK. When the second comparator PWM2 outputs a pulse signal, the inductor IL starts to discharge, the current IL of the inductor IL decreases, and the inductor IL stops discharging when the clock signal CLK triggers the falling edge.

[0175] When the first comparator PEAK2 triggers at time t0 and a pulse signal is generated, the mode switching unit MODE CTRL can control the first switch S1 to turn off, and the voltage VSENSE2 at the positive input terminal of the second comparator PWM2 will decrease by a value of VDC. The power circuit 110 will switch the control mode to COT control mode in the next cycle of the clock signal CLK, set the COT_MODE signal to 1, and the inductor L will discharge for a preset time (toff).

[0176] As can be understood, as mentioned earlier, based on the single-cycle signal EN and the first trigger signal PEAK2, exiting the COT control mode and entering the PWM control mode includes two cases, which will be discussed below. Figure 7a and Figure 7b Let me introduce it.

[0177] Figure 7a The figure shows the waveform of the pulse signal PEAK2 triggered within the first preset time period DT of the single-cycle signal EN.

[0178] Understandable. Figure 7a In the waveforms, CLK corresponds to the system clock signal, specifically the clock signal of the input mode switching unit MODE CTRL. IL corresponds to the current signal of inductor L. PEAK2 corresponds to the output signal of the first comparator PEAK2. PWM2 corresponds to the output signal of the second comparator PWM2. VO corresponds to the output voltage signal of the power circuit 110 output node. COT_MODE corresponds to the COT control mode waveform; when high, it indicates that the control circuit 120 is in COT control mode. VSENSE2 corresponds to the positive input signal of the second comparator PWM2. EN corresponds to the single-cycle signal EN.

[0179] Depend on Figure 7aAs can be seen, in COT control mode, when the first comparator PEAK2 triggers a pulse signal, the inductor IL discharges for a preset time toff. When the mode switching unit MODE CTRL receives N pulse signals output by the second comparator PWM2, the control circuit 120 exits the COT control mode stage. At this time, the mode switching unit MODE CTRL generates a single-cycle signal EN synchronized with the clock signal CLK. When the PEAK2 signal is triggered within the first preset time period of the single-cycle signal EN, i.e., at time t2, the drive circuit DRIVER drives switch M1 to turn off and switch M2 to turn on after time t2 within the period of the single-cycle signal EN, thereby controlling the inductor L to discharge. Furthermore, the mode switching unit MODE CTRL outputs a signal controlling the first switch S1 to turn on, and the voltage VSENSE2 at the positive input terminal of the second comparator PWM2 increases to a value of VDC. When the single-cycle signal EN becomes low, the mode switching unit MODE CTRL outputs a second-level signal, and the control circuit 120 enters the PWM control mode.

[0180] Figure 7b The figure shows the waveform of the pulse signal PEAK2 triggered within the first preset time period DT of the single-cycle signal EN.

[0181] Understandable. Figure 7b In the waveforms, CLK corresponds to the system clock signal, specifically the clock signal of the input mode switching unit MODE CTRL. IL corresponds to the current signal of inductor L. PEAK2 corresponds to the output signal of the first comparator PEAK2. PWM2 corresponds to the output signal of the second comparator PWM2. VO corresponds to the output voltage signal of the power circuit 110 output node. COT_MODE corresponds to the COT control mode waveform; when high, it indicates that the control circuit 120 is in COT control mode. VSENSE2 corresponds to the positive input signal of the second comparator PWM2. EN corresponds to the single-cycle signal EN.

[0182] Depend on Figure 7bAs can be seen, in COT control mode, when the first comparator PEAK2 triggers a pulse signal, the inductor L discharges for a preset time toff. When the mode switching unit MODE CTRL continuously receives N pulse signals output by the second comparator PWM2, the control circuit exits the COT control mode stage. At this time, the mode switching unit MODE CTRL generates a single-cycle signal EN synchronized with the clock signal CLK. If the PEAK2 signal is not triggered within the first preset time period of the single-cycle signal EN, then within the first preset time period DT of the single-cycle signal EN, the driver circuit drives switch M1 to continue conducting, and switch M2 to continue conducting, so as to control the inductor L to charge within the first preset time period DT; within the second preset time period T-DT of the single-cycle signal EN, the driver circuit drives switch M1 to turn off, and switch M2 to turn on, so as to control the inductor L to discharge within the second preset time period T-DT. Furthermore, the mode switching unit MODE CTRL outputs a signal to control the first switch S1 to conduct, and the voltage VSENSE2 at the positive input terminal of the second comparator PWM2 will increase by a magnitude of VDC. When the single-cycle signal EN goes low, the mode switching unit MODE CTRL outputs a second-level signal, and the control circuit 120 enters the PWM control mode.

[0183] It can be understood that the single-cycle signal EN is a transition period for switching between COT control mode and PWM control mode. During this period, a smooth transition between the two control modes is achieved, avoiding switching back and forth between control modes.

[0184] The following is combined with Figure 8 In the COT control mode, when the duty cycle of the output voltage of the power circuit 110 is too small, the control circuit 120 controls the switching frequency of switches M1 and M2 by controlling the preset time.

[0185] Understandable. Figure 8 In the diagram, IL corresponds to the current signal waveform of inductor L. COT_MODE corresponds to the COT control mode waveform; when high, it indicates that control circuit 120 is in COT control mode. VREF3 is the third reference voltage. D_DET corresponds to the output signal waveform of the third comparator D_DET. VFB corresponds to the voltage signal waveform between resistors R1 and R2; the voltage value of VFB can be considered as the output voltage VO of the power circuit.

[0186] Depend on Figure 8It can be seen that at time t3, the third comparator D_DET determines that the voltage VFB is smaller than the third reference voltage, and generates a high-level signal. The COT module 123 can reduce the voltage at the negative input terminal of the fourth comparator TOFF based on the high-level signal, thereby increasing the time for the fourth comparator TOFF to output the first-level signal, that is, reducing the operating frequency of the COT control mode. The discharge time of the inductor IL increases from toff0 toff1. At time t4, the third comparator D_DET determines that the voltage VFB is larger than the third reference voltage, and generates a low-level signal. The COT module 123 can increase the voltage at the negative input terminal of the fourth comparator TOFF based on the low-level signal, thereby reducing the time for the fourth comparator TOFF to output the first-level signal, that is, restoring the operating frequency of the COT control mode. The discharge time of the inductor IL decreases.

[0187] In some embodiments, the third reference voltage may be different when the frequency is reduced and when the frequency is restored, with the third reference voltage being higher when the frequency is restored.

[0188] The following is combined with Figure 9 The control method of the control circuit provided in the embodiments of this application will be introduced.

[0189] like Figure 9 As shown, the control method includes:

[0190] 901: When the detection module detects that the inductor current sampling signal in the power circuit starts to be greater than the first reference voltage, or when the inductor current sampling signal starts to be greater than the second reference voltage, it applies voltage hysteresis to the inductor current sampling signal, and when it determines that the hysteresis-induced inductor current sampling signal is greater than the first reference voltage, it outputs a first trigger signal to the control module, or when it determines that the hysteresis-induced inductor current sampling signal is greater than the second reference voltage, it outputs a second trigger signal to the control module.

[0191] If yes, it indicates that the power circuit is under heavy load and needs to be switched to the first control mode. Otherwise, it indicates that the power circuit is not under heavy load and the second control mode will still be used.

[0192] 902: Has the control module received the first trigger signal? If yes, it indicates that the power circuit is in a heavy load state and needs to be switched to the first control mode, i.e., proceed to step 903. Otherwise, it indicates that the power circuit is not in a heavy load state and the second control mode is still used, proceed to step 904.

[0193] 903: The control module outputs a first-level signal in the next cycle corresponding to the second control mode, controlling the power circuit switch to discharge within a preset time.

[0194] 904: The control module maintains the second control mode.

[0195] 905: Does the control module continuously receive multiple second trigger signals in the first control mode? If yes, it indicates that the power circuit is no longer in a heavy-load state and needs to switch to the second control mode, i.e., execute step 906. Otherwise, it indicates that the power circuit is still in a heavy-load state and the first control mode is still used, execute step 907.

[0196] 906: The control module outputs a second-level signal to control the power circuit to charge and discharge at a fixed frequency.

[0197] 907: The control module maintains the first control mode.

[0198] The following is based on Figure 4 Taking the circuit diagram shown as an example, and with the first control mode being COT control mode and the second control mode being PWM control mode, combined with... Figure 10 This application will now introduce another control method for a control circuit provided in an embodiment of the present application.

[0199] like Figure 10 As shown, the control method includes:

[0200] 1001: Is the first comparator PEAK2 triggered? If triggered, it indicates that the power circuit is under heavy load and needs to be switched to COT control mode, i.e., proceed to step 1002. Otherwise, it indicates that the power circuit is not under heavy load and still uses PWM control mode, proceed to step 1003.

[0201] 1002: The mode switching unit control mode is COT control mode.

[0202] 1003: The mode switching unit control mode is PWM control mode.

[0203] 1004: Has the second comparator PWM2 been triggered, and triggered multiple times? If yes, it indicates that the power circuit is no longer under heavy load and needs to be switched to PWM control mode, i.e., proceed to step 1005. Otherwise, it indicates that the power circuit is still under heavy load and still uses COT control mode, proceed to step 1002.

[0204] 1005: The control mode switching unit performs a hysteresis operation. Hysteresis operation includes voltage hysteresis and periodic hysteresis, as previously described and will not be repeated here. After the control mode switching unit performs the hysteresis operation, step 1003 is executed.

[0205] 1006: The third comparator D_DET determines whether the voltage VFB at the positive input terminal is greater than the third reference voltage VREF3. If so, the duty cycle of the output voltage of the surface power circuit is very small, and frequency reduction is required, i.e., step 1006 is executed.

[0206] 1007: The operating frequency of the COT module has decreased.

[0207] In the accompanying drawings, some structural or methodological features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. Rather, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular figure does not imply that such features are required in all embodiments, and in some embodiments, these features may be omitted or may be combined with other features.

[0208] like Figure 11 As shown in the figure, this application embodiment also provides a switching power supply, including a DC power supply 200 and a DC converter 100. The DC converter 100 includes a power circuit 110 and a control circuit 120. The DC power supply 200 is connected to the input side of the power circuit 110 and inputs a DC voltage to the power circuit 110.

[0209] The control circuit 120 includes a detection module 121 and a control module 122. The detection module 121 performs voltage hysteresis processing on the inductor current sampling signal when it detects that the inductor current sampling signal in the power circuit 110 starts to exceed a first reference voltage, or when it detects that the inductor current sampling signal starts to exceed a second reference voltage. When it is determined that the hysteresis-restricted inductor current sampling signal is greater than the first reference voltage, a first trigger signal is output to the control module 122. When it is determined that the hysteresis-restricted inductor current sampling signal is greater than the second reference voltage, a second trigger signal is output to the control module 122. The first trigger signal corresponds to a first control mode, and the second trigger signal corresponds to a second control mode.

[0210] The control module 122 is used to output a first level signal in the next cycle corresponding to the second control mode if a first trigger signal is received in the second control mode, and control the switch of the power circuit 110 to discharge within a preset time; if multiple second trigger signals are received continuously in the first control mode, the control module 122 outputs a second level signal and controls the switch of the power circuit 110 to charge and discharge at a fixed frequency.

[0211] It should be noted that all units / modules mentioned in the device embodiments of this application are logical units / modules. Physically, a logical unit / module can be a physical unit / module, a part of a physical unit / module, or a combination of multiple physical units / modules. The physical implementation of these logical units / modules themselves is not the most important factor; the combination of functions implemented by these logical units / modules is the key to solving the technical problems proposed in this application. Furthermore, to highlight the innovative aspects of this application, the above-described device embodiments of this application have not introduced units / modules that are not closely related to solving the technical problems proposed in this application. This does not mean that the above-described device embodiments do not contain other units / modules.

[0212] It should be noted that in the examples and description of this patent, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0213] Although this application has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art should understand that various changes in form and detail may be made thereto without departing from the spirit and scope of this application.

Claims

1. A dc-dc converter comprising a power circuit and a control circuit, characterized in that, The control circuit comprises a detection module and a control module, The detection module is configured to: perform voltage hysteresis processing on the inductor current sampling signal when it is detected that the inductor current sampling signal starts to be greater than a first reference voltage or when the inductor current sampling signal starts to be greater than a second reference voltage, the inductor current sampling signal being a signal obtained by sampling an inductor current and performing voltage-current conversion, and the inductor current sampling signal being represented as a voltage value; output a first trigger signal to the control module when it is judged that the hysteresis inductor current sampling signal is greater than the first reference voltage, and output a second trigger signal to the control module when it is judged that the hysteresis inductor current sampling signal is greater than the second reference voltage, wherein the first trigger signal corresponds to a first control mode, and the second trigger signal corresponds to a second control mode; The control module is configured to: receive the first trigger signal or the second trigger signal; The control module is further configured to: generate a one-cycle signal synchronized with a clock signal corresponding to the second control mode, and a period of the one-cycle signal comprises a first preset time period and a second preset time period; when the control module is in the first control mode and the control module receives the second trigger signal: if the control module receives the first trigger signal within the first preset time period of the period of the one-cycle signal, the control module controls the inductor of the power circuit to discharge in the remaining period of the one-cycle signal; if the control module does not receive the first trigger signal within the first preset time period of the period of the one-cycle signal, the control module controls the inductor of the power circuit to charge in the first preset time period of the one-cycle signal and to discharge in the second preset time period.

2. The direct current converter of claim 1, wherein The control module is configured to: if the first trigger signal is received in the second control mode, output a first level signal in a next period corresponding to the second control mode to control the switch of the power circuit to discharge in a preset time; if a plurality of second trigger signals are continuously received in the first control mode, output a second level signal to control the switch of the power circuit to charge and discharge at a fixed frequency.

3. The dc-dc converter according to claim 1 or 2, characterized in that The first control mode is a COT control mode, and the second control mode is a PWM control mode.

4. The dc-dc converter according to claim 1 or 2, characterized in that, The detection module comprises a hysteresis unit, a first detection unit, and a second detection unit. One end of the hysteresis unit is connected to a first end of the inductor of the power circuit, and the other end of the hysteresis unit is connected to the control module, and the hysteresis unit is further connected to the first detection unit and the second detection unit. The hysteresis unit is configured to output a hysteresis inductor current sampling signal to the first detection unit and the second detection unit when it is detected that the inductor current sampling signal starts to be greater than the first reference voltage or the inductor current sampling signal starts to be greater than the second reference voltage. The first detection unit is connected to the control module, and the first detection unit is configured to: output a first trigger signal to the control module when detecting that the delayed inductor current sampling signal is greater than the first reference voltage; The second detection unit is connected to the control module, and the second detection unit is configured to: output a second trigger signal to the control module when detecting that the delayed inductor current sampling signal is greater than the second reference voltage.

5. The dc-dc converter according to claim 1 or 2, characterized in that, The detection module comprises a delay unit, a first detection unit, and a second detection unit; The first detection unit is connected to the inductor and the control module, and the first detection unit is configured to: output a first trigger signal to the control module when detecting that the inductor current sampling signal is greater than the first reference voltage; The second detection unit is connected to the delay unit and the control module, and the second detection unit is configured to: output a second trigger signal to the control module when detecting that the sum of the inductor current sampling signal and the voltage of the delay unit is greater than the second reference voltage. One end of the delay unit is connected to the first end of the inductor of the power circuit, the other end of the delay unit is connected to the control module, and the delay unit is further connected to the second detection unit. The delay unit is configured to: change the delay voltage input to the first detection unit according to the control of the control module.

6. The dc to dc converter of claim 5, wherein, The delay unit comprises a delay voltage generation subunit and a first switch. The first end of the first switch is connected to the delay voltage generation subunit, the second end of the first switch is connected to the control module, and the third end of the first switch is connected to the second detection unit. The delay voltage generation subunit is configured to generate a preset delay voltage. The control module is configured to: in the first control mode, control the circuit between the delay voltage generation subunit and the second detection unit of the first switch to be in a conductive state, and the delay voltage is the preset delay voltage; when the control module receives a second trigger signal, control the circuit between the delay voltage generation subunit and the second detection unit of the first switch to be in a disconnected state, and the delay voltage is zero.

7. The dc-dc converter of claim 6, wherein, The first switch comprises a single-pole double-throw switch.

8. The dc-dc converter of claim 6, wherein, The first detection unit comprises a first sampling subunit and a first comparator, and the second detection unit comprises a second sampling subunit, a second comparator, and an operational amplifier. The first end of the first sampling subunit is connected to the first end of the inductor, and the other end of the first sampling subunit is connected to the first input end of the first comparator. The first sampling subunit is configured to sample the inductor current with a first sampling coefficient and output a corresponding first voltage value. The second input end of the first comparator is connected to the first reference voltage, and the first comparator is configured to compare the first voltage value output by the first sampling subunit with the first reference voltage. The first end of the second sampling subunit is connected to the first end of the inductor, and the other end of the second sampling subunit is connected to the first input end of the second comparator, and the second sampling subunit is configured to sample the inductor current at a second sampling coefficient and output a corresponding voltage value; The third end of the first switch is connected to the first input end of the second comparator; The first input end of the operational amplifier is connected to the second reference voltage, the first input end of the operational amplifier is connected to the output node of the power circuit, and the output end of the operational amplifier is connected to the second input end of the second comparator; The operational amplifier is configured to: amplify a voltage difference between the output voltage of the power circuit and the second reference voltage and output the amplified voltage difference to the second input end of the second comparator; and The output end of the second comparator is connected to the control module, and the second comparator is configured to compare the sum of the voltage value output by the second sampling subunit and the voltage output by the first switch with the amplified voltage difference output by the operational amplifier.

9. The dc to dc converter of claim 8, wherein, The second detection unit further comprises a slope voltage generation subunit connected to the first input end of the second comparator; The slope voltage generation subunit is configured to generate a voltage with a certain slope and superimpose the voltage on the voltage value output by the second sampling subunit to perform slope compensation on the inductor current.

10. The dc-dc converter of claim 8, wherein, The control module comprises a mode switching unit and a driving unit; One side of the mode switching unit is connected to the output ends of the first comparator and the second comparator, and the other side of the mode switching unit is connected to one side of the driving unit, and the mode switching unit is configured to generate a first level signal according to the first trigger signal output by the first comparator or output a second level signal to the driving unit according to the second trigger signal output by the second comparator; The other side of the driving unit is connected to the control ends of the first power switch and the second power switch in the power circuit, respectively, and is configured to control the on-off of the first power switch and the second power switch based on the first level signal or the second level signal to control the charging and discharging of the inductor in the power circuit.

11. The dc-dc converter of claim 10, wherein, The control module further comprises a latch connected between the mode switching unit and the driving unit, and the latch is configured to convert the pulse signal output by the mode switching unit into the first level signal or the second level signal.

12. The dc-dc converter according to any one of claims 1 to 9, characterized in that, The control circuit further comprises a fixed conduction time module; One side of the fixed conduction time module is connected to the input node and the output node of the power circuit, and the other side of the fixed conduction time module is connected to the control module. The fixed conduction time module is configured to output a first level signal with a preset time to the control module based on the detected input voltage and output voltage of the power circuit. The control module is configured to output the received first level signal with the preset time when the first trigger signal is received.

13. The dc-dc converter of claim 12, wherein, The control circuit further comprises a duty cycle detection module; The duty cycle detection module is connected to an output node of the power circuit and one side of the fixed conduction time module, and is configured to detect an output voltage of the power circuit and output a frequency control signal to the fixed conduction time module when the output voltage is greater than a third reference voltage. The fixed conduction time module is configured to: adjust the preset time based on the frequency control signal and output a first level signal of the adjusted preset time when the frequency control signal is received.

14. The dc-dc converter of claim 13, wherein, The duty cycle detection module comprises a third comparator. A first input end of the third comparator is connected to the third reference voltage, and a second input end of the third comparator is connected to the output node of the power circuit. The third comparator is configured to: compare the output voltage of the power circuit and the third reference voltage, and output the frequency control signal according to a comparison result.

15. The dc-dc converter of claim 13, wherein, The fixed conduction time module comprises a fourth comparator, a conduction resistor, a variable resistor, a conduction capacitor and a voltage-current converter. One end of the voltage-current converter is connected to the output node of the power circuit, and the other end of the voltage-current converter is connected to a first end of the conduction capacitor. The voltage-current converter is configured to convert the detected output voltage of the power circuit into a current, and the current output by the voltage-current converter is used to charge the conduction capacitor. The first end of the conduction capacitor is connected to a first input end of the fourth comparator, and a second end of the conduction capacitor is grounded. A first end of the conduction resistor is connected to an input node of the power circuit, and a second end of the conduction resistor is connected to a second input end of the fourth comparator and one end of the variable resistor.

16. The dc to dc converter of claim 15, wherein, The other end of the variable resistor is grounded.

17. A control method of a DC converter, applied to a DC converter, the DC converter comprising a power circuit and a control circuit, characterized in that, The output end of the fourth comparator is connected to the control module. The variable resistor is configured to change the resistance value of the variable resistor to change the preset time when the frequency control signal output by the duty cycle detection module is detected. The control circuit comprises a detection module and a control module. The method comprises: The detection module is configured to perform voltage hysteresis on an inductor current sampling signal when the inductor current sampling signal is detected to be greater than a first reference voltage or a second reference voltage, and output a first trigger signal to the control module when the hysteresis inductor current sampling signal is greater than the first reference voltage, or output a second trigger signal to the control module when the hysteresis inductor current sampling signal is greater than the second reference voltage. The inductor current sampling signal is a signal obtained by sampling an inductor current and performing voltage-current conversion, and is represented by a voltage value. The control module is configured to receive the first trigger signal or the second trigger signal. The method further comprises: The control module is configured to generate a one-cycle signal synchronized with a clock signal corresponding to a second control mode, and the period of the one-cycle signal comprises a first preset time period and a second preset time period. When the control module is in the first control mode, and the control module receives the second trigger signal: If the control module receives the first trigger signal within the first preset time period of the cycle of the single-cycle signal, the control module controls the inductance of the power circuit to discharge in the remaining cycle of the single-cycle signal; If the control module does not receive the first trigger signal within the first preset time period of the cycle of the single-cycle signal, the control module controls the inductance of the power circuit to charge in the first preset time period of the cycle of the single-cycle signal and to discharge in the second preset time period.

18. The control method of the direct current converter according to claim 17, further comprising: If the control module receives the first trigger signal, the control module outputs a first level signal in the next cycle corresponding to the second control mode to control the switch of the power circuit to discharge in a preset time. If the control module continuously receives a plurality of the second trigger signals in the first control mode, the control module outputs a second level signal to control the switch of the power circuit to charge and discharge at a fixed frequency. comprising:

19. A switched mode power supply characterized by a direct current power supply and the direct current converter according to any one of claims 1 to 16, wherein the direct current converter is configured to perform the control method of the direct current converter according to claim 17 or 18, and the direct current power supply is connected to an input side of the power circuit in the direct current converter. comprising:

20. A chip, characterized by a direct current power supply and the direct current converter according to any one of claims 1 to 16, wherein the direct current converter is configured to perform the control method of the direct current converter according to claim 17 or 18, and the direct current power supply is connected to an input side of the power circuit in the direct current converter. comprising:

21. An electronic device, comprising: a direct current power supply and the direct current converter according to any one of claims 1 to 16, wherein the direct current converter is configured to perform the control method of the direct current converter according to claim 17 or 18, and the direct current power supply is connected to an input side of the power circuit in the direct current converter. comprising: a direct current power supply and the direct current converter according to any one of claims 1 to 16, wherein the direct current converter is configured to perform the control method of the direct current converter according to claim 17 or 18, and the direct current power supply is connected to an input side of the power circuit in the direct current converter. comprising: a direct current power supply and the direct current converter according to any one of claims 1 to 16, wherein the direct current converter is configured to perform the control method of the direct current converter according to claim 17 or 18, and the direct current power supply is connected to an input side of the power circuit in the direct current converter.

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