Voltage conversion circuit and electronic device

Abstract

This application discloses a voltage conversion circuit and electronic device. The voltage conversion circuit includes: a voltage conversion unit for converting an input voltage and outputting a first voltage and an output voltage; a sampling conversion circuit electrically connected to the voltage conversion unit for sampling the current of the inductor in the voltage conversion unit and converting the current to output a second voltage; a slope compensation reference adjustment unit electrically connected to the sampling conversion circuit for receiving the second voltage and a common-mode voltage, generating an offset voltage based on the second voltage and the common-mode voltage, and outputting a third voltage and a fourth voltage; and a comparator electrically connected to both the voltage conversion unit and the slope compensation reference adjustment unit for receiving a reference voltage, the first voltage, the third voltage, and the fourth voltage, comparing the reference voltage, the first voltage, the third voltage, and the fourth voltage, and outputting a control signal to the voltage conversion unit to adjust the output voltage. This method effectively shortens the transient response time.

Description

Technical Field

[0001] This application relates to the field of voltage converter technology, and in particular to a voltage conversion circuit and electronic device. Background Technology

[0002] With the continuous development of technology in consumer electronics products such as mobile phones, the market has placed higher demands on the performance of consumer electronic chips. Among them, boost circuits, as a common power conversion circuit, have been widely used in various consumer electronics products.

[0003] Traditional boost circuits typically include peak current-mode controlled boost circuits and constant on-time (COT) controlled boost circuits. Peak current-mode controlled boost circuits use the output of an error amplifier (EA) to control the duty cycle, thus ensuring the accuracy of the output voltage. However, the performance of peak current-mode controlled boost circuits is limited by the bandwidth of the error amplifier, and load switching can lead to significant transient voltage deviations and long transient response times. Utility Model Content

[0004] This application mainly provides a voltage conversion circuit and electronic device to solve the problem of long transient response time.

[0005] This application provides a voltage conversion circuit, including:

[0006] The voltage conversion unit is used to convert the input voltage and output a first voltage and an output voltage;

[0007] A sampling conversion circuit, electrically connected to the voltage conversion unit, is used to sample the current of the inductor in the voltage conversion unit and convert the current to output a second voltage.

[0008] The slope compensation reference adjustment unit is electrically connected to the sampling conversion circuit, and is used to receive the second voltage and the common-mode voltage, generate an offset voltage based on the second voltage and the common-mode voltage, and output a third voltage and a fourth voltage.

[0009] The comparator is electrically connected to the voltage conversion unit and the slope compensation reference adjustment unit, respectively, and is used to receive the reference voltage, the first voltage, the third voltage and the fourth voltage, compare the reference voltage, the first voltage, the third voltage and the fourth voltage, and output a control signal to the voltage conversion unit to adjust the output voltage.

[0010] The slope compensation reference adjustment unit is used to superimpose the second voltage and the first voltage in phase, and the offset voltage is used to eliminate the inherent error caused by superimposing the second voltage and the first voltage in phase; the offset voltage is obtained by subtracting the fourth voltage from the common mode voltage, and the offset voltage is half of the second voltage.

[0011] The comparator is used to compare the reference voltage, the first voltage, the third voltage, and the fourth voltage. The comparator is configured such that the comparison determination condition of the comparator is that the sum of the first voltage and the third voltage is equal to the sum of the reference voltage and the fourth voltage; when the third voltage is equal to the fourth voltage, the first voltage is equal to the reference voltage, and the comparator outputs the control signal.

[0012] The slope compensation reference adjustment unit includes a coupling capacitor, a first resistor, a second resistor, a current source, and a voltage source. One end of the first resistor is grounded through the voltage source, and the other end of the first resistor is connected to the second input terminal of the comparator. One end of the second resistor is connected to one end of the first resistor, and the other end of the second resistor is grounded through the current source and connected to the third input terminal of the comparator. One end of the coupling capacitor is connected to the output terminal of the sampling conversion circuit, and the other end of the coupling capacitor is connected between the other end of the first resistor and the second input terminal of the comparator. The first input terminal of the comparator receives the reference voltage.

[0013] The voltage conversion unit includes a basic voltage conversion circuit, a drive circuit, and a feedback circuit. The basic voltage conversion circuit is electrically connected to both the drive circuit and the feedback circuit. The drive circuit controls the basic voltage conversion circuit to be turned on or off. The basic voltage conversion circuit outputs the output voltage to the feedback circuit, causing the feedback circuit to output the first voltage. The fourth input terminal of the comparator is electrically connected to the feedback circuit, and the output terminal of the comparator is electrically connected to the drive circuit. The comparator receives the first voltage through the feedback circuit, compares the reference voltage, the first voltage, the third voltage, and the fourth voltage, and outputs the control signal to the drive circuit.

[0014] The basic voltage conversion circuit includes a power supply, an inductor, a first switching transistor, a second switching transistor, a first capacitor, and a third resistor. The negative terminal of the power supply is grounded, and the positive terminal of the power supply is connected to one end of the inductor. The other end of the inductor is connected to the first terminal of the first switching transistor and the other end of the sampling conversion circuit. The second terminal of the first switching transistor is connected to one end of the first capacitor and one end of the third resistor. The third terminal of the first switching transistor is connected to the driving circuit. One end of the third resistor is connected to the first end of the feedback circuit. The other end of the third resistor is connected to the negative terminal of the power supply and the second terminal of the feedback circuit. The other end of the first capacitor is connected between the other end of the third resistor and the negative terminal of the power supply. The first end of the second switching transistor is connected between the other end of the inductor and the first end of the first switching transistor. The second end of the second switching transistor is connected between the other end of the first capacitor and the negative terminal of the power supply. The third end of the second switching transistor is connected to the driving circuit.

[0015] The feedback circuit includes a fourth resistor and a fifth resistor. One end of the fourth resistor is connected to one end of the third resistor, and the other end of the fourth resistor is connected to one end of the fifth resistor. The other end of the fifth resistor is connected to the other end of the third resistor. The fourth input terminal of the comparator is connected between the other end of the fourth resistor and one end of the fifth resistor.

[0016] The comparator is used to receive the first voltage and multiply the output voltage by a feedback coefficient to obtain the first voltage; wherein the feedback coefficient is equal to the ratio of the resistance value of the fourth resistor to the sum of the resistance values ​​of the fourth resistor and the fifth resistor.

[0017] The voltage conversion circuit further includes a control circuit. One end of the control circuit is electrically connected to the output of the comparator, and the other end of the control circuit is electrically connected to the drive circuit. The control circuit is used to receive the control signal and control the drive circuit to turn the first switch and the second switch on or off based on the control signal.

[0018] This application also provides an electronic device including the voltage conversion circuit described above.

[0019] The beneficial effects of this application are: this application compares the reference voltage, the first voltage, the third voltage and the fourth voltage through a comparator, and outputs a control signal to the voltage conversion unit to adjust the setting of the output voltage. Compared with the BOOST circuit controlled by peak current mode, the error amplifier is eliminated, which can effectively shorten the transient response time. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0021] Figure 1 This is a circuit diagram of an embodiment of the peak current mode controlled BOOST circuit provided in this application;

[0022] Figure 2 This is a circuit diagram of an embodiment of the COT-controlled BOOST circuit provided in this application;

[0023] Figure 3 yes Figure 2 A waveform diagram of an embodiment of the output voltage, ripple voltage, and feedback voltage;

[0024] Figure 4 This is a circuit diagram of one embodiment of the voltage conversion circuit provided in this application;

[0025] Figure 5 yes Figure 4 A waveform diagram of an embodiment of the output voltage, common-mode voltage, first voltage, third voltage, fourth voltage, and reference voltage. Detailed Implementation

[0026] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0028] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order, or primary and secondary relationship of the indicated technical features.

[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0031] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0032] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a connection between two components or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0033] See Figure 1 As shown, Figure 1 This is a circuit diagram of an embodiment of the peak current mode controlled BOOST circuit provided in this application. Figure 1 As shown, the peak current mode controlled BOOST circuit 100 includes a power supply V, an inductor L, a first switch Q1, a second switch Q2, a driver circuit DRIVER, a capacitor C, a first resistor R1, a second resistor R2, a third resistor R3, an error amplifier (EA), and a comparator Comp.

[0034] The error amplifier EA receives the reference voltage VREF and the feedback voltage VOFB, and outputs a control signal to the comparator Comp. The comparator Comp receives the compensation signal RAMP and the control signal. The feedback voltage VOFB is the product of the feedback coefficient β and the output voltage VOUT, i.e., VOFB = β * VOUT. The feedback coefficient β is equal to the ratio of the resistance value Rbot of the third resistor R3 to the sum of the resistance values ​​Rtop of the second resistor R2 and Rbot of the third resistor R3, i.e., β = Rbot / (Rtop + Rbot). The feedback coefficient β is less than or equal to 1.

[0035] As can be seen, the peak current-mode controlled BOOST circuit 100 controls the duty cycle through the output of the error amplifier EA, thereby ensuring the accuracy of the output voltage VOUT. However, the performance of the peak current-mode controlled BOOST circuit 100 is limited by the bandwidth of the error amplifier EA, which can cause a large transient deviation in the output voltage VOUT and a long transient response time when the load is switched.

[0036] See Figure 2 and Figure 3 As shown, Figure 2 This is a circuit diagram of an embodiment of the COT-controlled BOOST circuit provided in this application; Figure 3 yes Figure 2 A waveform diagram illustrating one embodiment of the output voltage, ripple voltage, and feedback voltage. (See diagram below.) Figure 2 As shown, the COT-controlled BOOST circuit 200 includes a power supply V, an inductor L, a first switching transistor Q1, a second switching transistor Q2, a driver circuit DRIVER, a capacitor C, a first resistor R1, a second resistor R2, a third resistor R3, a comparator Comp, and a coupling capacitor Cc.

[0037] The COT-controlled BOOST circuit 200 adjusts its duty cycle by directly comparing the feedback voltage VOFB and the reference voltage VREF through a comparator Comp, eliminating the error amplifier EA in the peak current-mode controlled BOOST circuit 100. This results in faster transient response and less voltage fluctuation. However, due to the phase difference between the output voltage VOUT change and the inductor L current (voltage change lags behind current change), subharmonic oscillations are introduced. Therefore, the COT-controlled BOOST circuit 200 adds slope compensation (coupling capacitor Cc) to eliminate subharmonic oscillations. However, while the existing slope compensation can effectively suppress oscillations, it causes the average value VOFB_avg of the feedback voltage VOFB to be higher than the reference voltage VREF by about half a ripple peak-to-peak value of 0.5*Vpp (ripple voltage), resulting in an inherent error. Figure 3As shown. Therefore, the average value of the output voltage VOUT will also be 0.5*Vpp / β higher than the set voltage. That is, although the existing slope compensation can effectively suppress oscillation, it also introduces inherent errors, resulting in a large accuracy error in the output voltage VOUT.

[0038] Please see Figure 4 As shown, Figure 4 This is a circuit diagram of an embodiment of the voltage conversion circuit provided in this application. The voltage conversion circuit 1 of this embodiment includes a voltage conversion unit 10, a sampling conversion circuit 20, a slope compensation reference adjustment unit 30, and a comparator 40.

[0039] The voltage conversion unit 10 is used to convert the input voltage VIN and output the first voltage VOFB and the output voltage VOUT.

[0040] In some embodiments, the voltage conversion unit 10 is used to convert the input voltage VIN to generate an output voltage VOUT, and then convert the output voltage VOUT to output a first voltage VOFB.

[0041] The voltage conversion unit 10 is used to boost the input voltage VIN to obtain the output voltage VOUT. In other embodiments, the voltage conversion unit 10 is used to buck the input voltage VIN to obtain the output voltage VOUT, or the voltage conversion unit 10 is used to boost and then buck the input voltage VIN to obtain the output voltage VOUT.

[0042] The first voltage VOFB, also called the feedback voltage, is a voltage signal sampled from the output of the voltage conversion unit 10, reflecting the state of the actual output voltage VOUT. The first voltage VOFB is a proportional signal to the output voltage VOUT and can be obtained through a voltage divider resistor or other sampling methods. For example, by using a voltage divider resistor at the output of the voltage conversion unit 10 to reduce the output voltage VOUT to a suitable level, the second voltage VOFB is obtained.

[0043] The sampling conversion circuit 20 is electrically connected to the voltage conversion unit 10. It is used to sample the current of the inductor L in the voltage conversion unit 10 and output the second voltage VPP after converting the current.

[0044] In some embodiments, the sampling conversion circuit 20 is electrically connected to one end of the inductor L in the voltage conversion unit 10, so that the sampling conversion circuit 20 samples the current of the inductor L. The sampling conversion circuit 20 detects the change in current in the inductor L, converts the current, and outputs a voltage signal, namely the second voltage VPP.

[0045] The second voltage, VPP, is also called the ripple voltage. The ripple voltage is a voltage signal related to the AC component (ripple) in the output voltage VOUT. The second voltage, VPP, refers to the AC component superimposed on the DC output voltage VOUT.

[0046] The slope compensation reference adjustment unit 30 is electrically connected to the sampling conversion circuit 20. It is used to receive the second voltage VPP and the common mode voltage VCM, generate the offset voltage ΔV based on the second voltage VPP and the common mode voltage VCM, and output the third voltage VRAMP and the fourth voltage VRAMP_BIAS.

[0047] In some embodiments, the common-mode voltage VCM is provided by a voltage source and refers to the average voltage of two input signals relative to the same reference point (such as ground); the common-mode voltage VCM is used to provide a reference point for the slope compensation reference adjustment unit 30 so as to generate a stable fourth voltage VRAMP_BIAS in conjunction with the second voltage VPP.

[0048] In this embodiment, comparator 40 is also called a dual differential input single-ended output comparator, which includes two independent differential pairs: reference voltage VREF, first voltage VOFB, and third voltage VRAMP, fourth voltage VRAMP_BIAS. The working principle of comparator 40 is as follows: when the sum of reference voltage VREF and fourth voltage VRAMP_BIAS is greater than the sum of first voltage VOFB and third voltage VRAMP, comparator 40 outputs a high level; when the sum of reference voltage VREF and fourth voltage VRAMP_BIAS is less than the sum of first voltage VOFB and third voltage VRAMP, comparator 40 outputs a low level.

[0049] Among them, the third voltage VRAMP refers to the slope compensation signal, which is a voltage signal that follows the change of inductor L current over time. That is, the third voltage VRAMP is a dynamic voltage signal that reflects the changing trend of inductor L current. The fourth voltage VRAMP_BIAS, also called the slope compensation reference voltage, is obtained by superimposing the common-mode voltage VCM on half of the peak-to-peak value of the AC part of the predicted second voltage VPP (1 / 2*VPP). It is a static voltage signal. The third voltage VRAMP and the fourth voltage VRAMP_BIAS are used to introduce dynamic and static voltage components respectively to optimize the dynamic performance of voltage conversion circuit 1 and reduce subharmonic oscillations.

[0050] The offset voltage ΔV is a constant voltage signal calculated by the slope compensation reference adjustment unit 30 based on the second voltage VPP and the common-mode voltage VCM. It is used to adjust the amplitudes of the third voltage VRAMP and the fourth voltage VRAMP_BIAS, making the input signal of the comparator 40 more stable and thus reducing subharmonic oscillations. Specifically, since the offset voltage ΔV is related to the second voltage VPP, it can dynamically adjust the third voltage VRAMP and the fourth voltage VRAMP_BIAS according to changes in the second voltage VPP, thereby improving the stability of the voltage conversion circuit 1.

[0051] In some embodiments, comparator 40 receives a first voltage VOFB through voltage conversion unit 10, a third voltage VRAMP and a fourth voltage VRAMP_BIAS through slope compensation reference adjustment unit 30, and a reference voltage VREF through voltage source. After comparing and determining the reference voltage VREF, the first voltage VOFB, the third voltage VRAMP and the fourth voltage VRAMP_BIAS, comparator 40 outputs a control signal to voltage conversion unit 10 to adjust the output voltage VOUT and ensure the accuracy of the output voltage VOUT.

[0052] In this embodiment, the reference voltage VREF, the first voltage VOFB, the third voltage VRAMP, and the fourth voltage VRAMP_BIAS are compared by the comparator 40, and a control signal is output to the voltage conversion unit 10 to adjust the setting of the output voltage VOUT. Compared with the BOOST circuit controlled by the peak current mode, the error amplifier EA is omitted, which can effectively shorten the transient response time.

[0053] This embodiment also utilizes the offset voltage ΔV generated by the slope compensation reference adjustment unit 30. The slope compensation reference adjustment unit 30 outputs a third voltage VRAMP and a fourth voltage VRAMP_BIAS to the comparator 40, compared to... Figure 2 The COT-controlled BOOST circuit and the offset voltage ΔV generated by the ramp compensation reference adjustment unit 30 can effectively eliminate inherent errors and reduce the accuracy error of the output voltage VOUT.

[0054] According to some embodiments of this application, the slope compensation reference adjustment unit 30 is used to superimpose the second voltage VPP and the first voltage VOFB in phase, and the offset voltage ΔV is used to eliminate the inherent error caused by superimposing the second voltage VPP and the first voltage VOFB in phase; the offset voltage ΔV is obtained by subtracting the fourth voltage VRAMP_BIAS from the common mode voltage VCM, and the offset voltage ΔV is half of the second voltage VPP.

[0055] In this context, "in-phase superposition" refers to the addition of the second voltage VPP and the first voltage VOFB in the same phase. Subtracting the fourth voltage VRAMP_BIAS from the common-mode voltage VCM yields the offset voltage ΔV, which is half the value of the second voltage VPP. Therefore, the formula for the offset voltage ΔV is: ΔV = VCM - VOFB = 1 / 2 * VPP.

[0056] In some embodiments, when the second voltage VPP is superimposed on the first voltage VOFB in phase, the average value of the feedback voltage VOFB will increase the average value of VPP, that is, the average value of the feedback voltage VOFB will increase by half of the second voltage VPP, thereby generating an inherent error 1 / 2*VPP; the slope compensation reference adjustment unit 30 is connected to the comparator 40, and the slope compensation reference adjustment unit 30 generates an offset voltage ΔV based on the second voltage VPP and the common-mode voltage VCM; since the offset voltage ΔV is half of the second voltage VPP, the inherent error 1 / 2*VPP can be eliminated by the offset voltage ΔV of the slope compensation reference adjustment unit 30.

[0057] In this embodiment, by introducing an offset voltage ΔV = 1 / 2 * VPP, the slope compensation reference adjustment unit 30 can accurately eliminate the inherent error caused by the in-phase superposition of the second voltage VPP to the first voltage VOFB, thereby restoring the average value of the feedback voltage VOFB to the original set value and improving the accuracy of the output voltage VOUT.

[0058] According to some embodiments of this application, see Figure 5 As shown, Figure 5 yes Figure 4 The diagram shows waveforms of the output voltage, common-mode voltage, first voltage, third voltage, fourth voltage, and reference voltage in one embodiment. In this embodiment, comparator 40 is used to compare the reference voltage VREF, the first voltage VOFB, the third voltage VRAMP, and the fourth voltage VRAMP_BIAS. Comparator 40 is configured such that the comparison condition is that the sum of the first voltage VOFB and the third voltage VRAMP equals the sum of the reference voltage VREF and the fourth voltage VRAMP_BIAS. When the third voltage VRAMP equals the fourth voltage VRAMP_BIAS, the first voltage VOFB equals the reference voltage VREF, and comparator 40 outputs a control signal.

[0059] The comparator 40 compares the reference voltage VREF, the first voltage VOFB, the third voltage VRAMP, and the fourth voltage VRAMP_BIAS. The comparison condition of the comparator 40 is that the sum of the first voltage VOFB and the third voltage VRAMP is equal to the sum of the reference voltage VREF and the fourth voltage VRAMP_BIAS. That is, the comparison condition of the comparator 40 is: VOFB + VRAMP = VREF + VRAMP_BIAS.

[0060] The comparison criteria of comparator 40 are combined with Figure 5 It can be seen that when the third voltage VRAMP equals the fourth voltage VRAMP_BIAS, that is, VRAMP=VRAMP_BIAS, the first voltage VOFB equals the reference voltage VREF; at this time, the comparator 40 outputs a control signal to the voltage conversion unit 10 so that the voltage conversion unit 10 adjusts the output voltage VOUT through the control signal to ensure the accuracy of the output voltage VOUT.

[0061] In this embodiment, the comparison condition of comparator 40 is: VOFB+VRAMP=VREF+VRAMP_BIAS, which ensures that VOFB=VREF when VRAMP=VRAMP_BIAS, thereby outputting a control signal to ensure the output accuracy of the output voltage VOUT in the voltage conversion unit 10.

[0062] According to some embodiments of this application, the slope compensation reference adjustment unit 30 includes a coupling capacitor Cc, a first resistor R1, a second resistor R2, a current source I, and a voltage source U. One end of the first resistor R1 is grounded through the voltage source U, and the other end of the first resistor R1 is connected to the second input terminal of the comparator 40. One end of the second resistor R2 is connected to one end of the first resistor R1, and the other end of the second resistor R2 is grounded through the current source I. The other end of the second resistor R2 is also connected to the third input terminal of the comparator 40. One end of the coupling capacitor Cc is connected to the output terminal of the sampling conversion circuit 20, and the other end of the coupling capacitor Cc is connected between the other end of the first resistor R1 and the second input terminal of the comparator 40. The first input terminal of the comparator 40 receives the reference voltage VREF.

[0063] In some embodiments, the second voltage VPP is superimposed in phase to the first voltage VOFB via a coupling capacitor Cc. A voltage source U is used to provide the common-mode voltage VCM; a current source I is used to provide a base DC voltage for the fourth voltage VRAMP_BIAS, which may or may not be zero.

[0064] like Figure 4 As shown, the common-mode voltage VCM is superimposed with the offset voltage ΔV to obtain the fourth voltage VRAMP_BIAS. Therefore, the fourth voltage VRAMP_BIAS is a static voltage signal.

[0065] In this embodiment, a slope compensation reference adjustment unit 30 is formed by coupling capacitor Cc and first resistor R1 and second resistor R2. The slope compensation reference adjustment unit 30 can accurately generate offset voltage ΔV and eliminate inherent errors through offset voltage ΔV. By dynamically adjusting the third voltage VRAMP and the fourth voltage VRAMP_BIAS, the slope compensation reference adjustment unit 30 can enable comparator 40 to respond to load changes more quickly during load switching, thereby improving the dynamic response speed of voltage conversion circuit 1.

[0066] According to some embodiments of this application, the voltage conversion unit 10 includes a basic voltage conversion circuit 11, a driving circuit 12, and a feedback circuit 13. The basic voltage conversion circuit 11 is electrically connected to the driving circuit 12 and the feedback circuit 13, respectively. The driving circuit 12 is used to control the basic voltage conversion circuit 11 to be turned on or off. The basic voltage conversion circuit 11 outputs an output voltage VOUT to the feedback circuit 13 so that the feedback circuit 13 outputs a first voltage VOFB. The fourth input terminal of the comparator 40 is electrically connected to the feedback circuit 13, and the output terminal of the comparator 40 is electrically connected to the driving circuit 12. The comparator 40 is used to receive the first voltage VOFB through the feedback circuit 13, compare the reference voltage VREF, the first voltage VOFB, the third voltage VRAMP, and the fourth voltage VRAMP_BIAS, and output a control signal to the driving circuit 12.

[0067] The basic voltage conversion circuit 11 includes, but is not limited to, a boost circuit, a buck circuit, or a boost-buck circuit.

[0068] According to some embodiments of this application, the basic voltage conversion circuit 11 includes a power supply VCC, an inductor L, a first switch Q1, a second switch Q2, a first capacitor C1, and a third resistor R3. The negative terminal of the power supply VCC is grounded, the positive terminal of the power supply VCC is connected to one end of the inductor L, the other end of the inductor L is connected to the first terminal of the first switch Q1 and the other end of the sampling conversion circuit 20, the second terminal of the first switch Q1 is connected to one end of the first capacitor C1 and one end of the third resistor R3, and the third terminal of the first switch Q1 is connected to the drive circuit 12. One end of the third resistor R3 is connected to the first end of the feedback circuit 13, and the other end of the third resistor R3 is connected to the negative terminal of the power supply VCC and the second end of the feedback circuit 13 respectively. The other end of the first capacitor C1 is connected between the other end of the third resistor R3 and the negative terminal of the power supply VCC. The first end of the second switch Q2 is connected between the other end of the inductor L and the first end of the first switch Q1. The second end of the second switch Q2 is connected between the other end of the first capacitor C1 and the negative terminal of the power supply VCC. The third end of the second switch Q2 is connected to the drive circuit 12.

[0069] The third resistor R3 is a schematic load, which can be a resistor or a current-type load.

[0070] In some embodiments, the base voltage conversion circuit 11 is a BOOST circuit, and the comparator 40 outputs a control signal to the drive circuit 12. The drive circuit 12 controls the first switch Q1 and the second switch Q2 to be turned on or off according to the output signal, that is, adjusts the duty cycle to ensure the output accuracy of the output voltage VOUT of the base voltage conversion circuit 11.

[0071] In this embodiment, the first switch Q1 is a PMOS transistor, and the second switch Q2 is an NMOS transistor. The first terminal of the first switch Q1 and the first terminal of the second switch Q2 are the drains, the second terminals of the first switch Q1 and the second switch Q2 are the sources, and the third terminals of the first switch Q1 and the second switch Q2 are the gates. In other embodiments, the first switch Q1 and the second switch Q2 are transistors.

[0072] According to some embodiments of this application, the feedback circuit 13 includes a fourth resistor R4 and a fifth resistor R5. One end of the fourth resistor R4 is connected to one end of the third resistor R3, and the other end of the fourth resistor R4 is connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is connected to the other end of the third resistor R3. The fourth input terminal of the comparator 40 is connected between the other end of the fourth resistor R4 and one end of the fifth resistor R5.

[0073] Among them, the fourth resistor R4 and the fifth resistor R5 are used to divide the output voltage VOUT; the fourth input terminal of comparator 40 receives the first voltage VOFB through the fourth resistor R4 and the fifth resistor R5.

[0074] In this embodiment, the first voltage VOFB is accurately generated by the voltage division of the fourth resistor R4 and the fifth resistor R5 in the feedback circuit 13.

[0075] According to some embodiments of this application, comparator 40 is used to receive a first voltage VOFB and multiply the output voltage VOUT by a feedback coefficient β to obtain the first voltage VOFB; wherein, the feedback coefficient β is equal to the ratio of the resistance value Rbot of the fifth resistor R5 to the sum of the resistance value Rtop of the fourth resistor R4 and the resistance value Rbot of the fifth resistor R5.

[0076] The formula for calculating the feedback coefficient β is: Rbot / (Rtop+Rbot), and the feedback coefficient β is less than or equal to 1; the formula for calculating the first voltage VOFB is: VOFB=VOUT*β, and the first voltage VOFB can be obtained by substituting the feedback coefficient β.

[0077] According to some embodiments of this application, such as Figure 4As shown, the voltage conversion circuit 1 in this embodiment also includes a control circuit 50. One end of the control circuit 50 is electrically connected to the output terminal of the comparator 40, and the other end of the control circuit 50 is electrically connected to the drive circuit 12. The control circuit 50 is used to receive control signals and control the drive circuit 12 to drive the first switch Q1 and the second switch Q2 to turn on or off based on the control signals.

[0078] For example, such as Figure 5 As shown, when the third voltage VRAMP = the fourth voltage VRAMP_BIAS, the first voltage VOFB = the reference voltage VREF. The comparator 40 outputs a control signal, and the control circuit 50 generates a drive signal PWMO based on the control signal. The drive signal PWMO controls the drive circuit 12 to drive the first switch Q1 and the second switch Q2 to turn on or off, that is, the duty cycle is adjusted by the drive signal PWMO.

[0079] In some embodiments, the base voltage conversion circuit 11 outputs an output voltage VOUT, and the feedback circuit 13 generates a first voltage VOFB based on the output voltage VOUT; the sampling conversion circuit 20 samples the current of the inductor L and converts it to output a second voltage VPP; the slope compensation reference adjustment unit 30 generates an offset voltage ΔV based on the second voltage VPP and the common-mode voltage VCM, and outputs a third voltage VRAMP and a fourth voltage VRAMP_BIAS; the comparator 40 receives the reference voltage VREF, the first voltage VOFB, the third voltage VRAMP, and the fourth voltage VRAMP_BIAS, compares them, and outputs a control signal, i.e., outputs a control signal based on the comparison judgment condition; the control circuit 50 controls the drive circuit 12 to drive the first switch Q1 and the second switch Q2 to turn on or off based on the control signal, so as to adjust the accuracy of the output voltage VOUT.

[0080] This implementation simplifies the design of the voltage conversion circuit 1 by introducing the control circuit 50, reduces costs, and significantly improves performance.

[0081] Another embodiment of this application provides an electronic device, including the voltage conversion circuit 1 described in the above embodiment. The electronic device includes, but is not limited to, a mobile phone, computer, watch, or industrial control system.

[0082] In summary, this application compares the reference voltage VREF, the first voltage VOFB, the third voltage VRAMP, and the fourth voltage VRAMP_BIAS using comparator 40, and outputs a control signal to the voltage conversion unit 10 to adjust the setting of the output voltage VOUT. Compared with the peak current mode controlled BOOST circuit, the error amplifier EA is omitted, which can effectively shorten the transient response time. Furthermore, the slope compensation reference adjustment unit 30 generates an offset voltage ΔV, and the slope compensation reference adjustment unit 30 outputs the third voltage VRAMP and the fourth voltage VRAMP_BIAS to the comparator 40. Compared with the traditional COT controlled BOOST circuit, the offset voltage ΔV generated by the slope compensation reference adjustment unit 30 can effectively eliminate inherent errors and reduce the accuracy error of the output voltage VOUT.

[0083] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A voltage conversion circuit, characterized in that, include: The voltage conversion unit is used to convert the input voltage and output a first voltage and an output voltage; A sampling conversion circuit, electrically connected to the voltage conversion unit, is used to sample the current of the inductor in the voltage conversion unit and convert the current to output a second voltage. The slope compensation reference adjustment unit is electrically connected to the sampling conversion circuit, and is used to receive the second voltage and the common-mode voltage, generate an offset voltage based on the second voltage and the common-mode voltage, and output a third voltage and a fourth voltage. The comparator is electrically connected to the voltage conversion unit and the slope compensation reference adjustment unit, respectively, and is used to receive the reference voltage, the first voltage, the third voltage and the fourth voltage, compare the reference voltage, the first voltage, the third voltage and the fourth voltage, and output a control signal to the voltage conversion unit to adjust the output voltage.

2. The voltage conversion circuit according to claim 1, characterized in that, The slope compensation reference adjustment unit is used to superimpose the second voltage and the first voltage in phase, and the offset voltage is used to eliminate the inherent error caused by superimposing the second voltage and the first voltage in phase. The offset voltage is obtained by subtracting the fourth voltage from the common-mode voltage, and the offset voltage is half of the second voltage.

3. The voltage conversion circuit according to claim 2, characterized in that, The comparator is used to compare the reference voltage, the first voltage, the third voltage, and the fourth voltage. The comparator is configured such that the comparison determination condition of the comparator is that the sum of the first voltage and the third voltage is equal to the sum of the reference voltage and the fourth voltage; when the third voltage is equal to the fourth voltage, the first voltage is equal to the reference voltage, and the comparator outputs the control signal.

4. The voltage conversion circuit according to any one of claims 1-3, characterized in that, The slope compensation reference adjustment unit includes a coupling capacitor, a first resistor, a second resistor, a current source, and a voltage source. One end of the first resistor is grounded through the voltage source, and the other end of the first resistor is connected to the second input terminal of the comparator. One end of the second resistor is connected to one end of the first resistor, and the other end of the second resistor is grounded through the current source and connected to the third input terminal of the comparator. One end of the coupling capacitor is connected to the output terminal of the sampling conversion circuit, and the other end of the coupling capacitor is connected between the other end of the first resistor and the second input terminal of the comparator. The first input terminal of the comparator receives the reference voltage.

5. The voltage conversion circuit according to claim 1, characterized in that, The voltage conversion unit includes a basic voltage conversion circuit, a drive circuit, and a feedback circuit. The basic voltage conversion circuit is electrically connected to both the drive circuit and the feedback circuit. The drive circuit controls the basic voltage conversion circuit to be turned on or off. The basic voltage conversion circuit outputs the output voltage to the feedback circuit, causing the feedback circuit to output the first voltage. The fourth input terminal of the comparator is electrically connected to the feedback circuit, and the output terminal of the comparator is electrically connected to the drive circuit. The comparator receives the first voltage through the feedback circuit, compares the reference voltage, the first voltage, the third voltage, and the fourth voltage, and outputs the control signal to the drive circuit.

6. The voltage conversion circuit according to claim 5, characterized in that, The basic voltage conversion circuit includes a power supply, an inductor, a first switching transistor, a second switching transistor, a first capacitor, and a third resistor. The negative terminal of the power supply is grounded, and the positive terminal of the power supply is connected to one end of the inductor. The other end of the inductor is connected to the first terminal of the first switching transistor and the other end of the sampling conversion circuit. The second terminal of the first switching transistor is connected to one end of the first capacitor and one end of the third resistor. The third terminal of the first switching transistor is connected to the driving circuit. One end of the third resistor is connected to the first end of the feedback circuit, and the other end of the third resistor is connected to the negative terminal of the power supply and the second terminal of the feedback circuit. The other end of the first capacitor is connected between the other end of the third resistor and the negative terminal of the power supply. The first end of the second switching transistor is connected between the other end of the inductor and the first end of the first switching transistor. The second end of the second switching transistor is connected between the other end of the first capacitor and the negative terminal of the power supply. The third end of the second switching transistor is connected to the driving circuit.

7. The voltage conversion circuit according to claim 6, characterized in that, The feedback circuit includes a fourth resistor and a fifth resistor. One end of the fourth resistor is connected to one end of the third resistor, and the other end of the fourth resistor is connected to one end of the fifth resistor. The other end of the fifth resistor is connected to the other end of the third resistor. The fourth input terminal of the comparator is connected between the other end of the fourth resistor and one end of the fifth resistor.

8. The voltage conversion circuit according to claim 7, characterized in that, The comparator is used to receive the first voltage and multiply the output voltage by a feedback coefficient to obtain the first voltage; wherein, the feedback coefficient is equal to the ratio of the resistance value of the fourth resistor to the sum of the resistance values ​​of the fourth resistor and the fifth resistor.

9. The voltage conversion circuit according to claim 6, characterized in that, The voltage conversion circuit further includes a control circuit. One end of the control circuit is electrically connected to the output of the comparator, and the other end of the control circuit is electrically connected to the drive circuit. The control circuit is used to receive the control signal and control the drive circuit to turn the first switch and the second switch on or off based on the control signal.

10. An electronic device, characterized in that, Includes the voltage conversion circuit as described in any one of claims 1-9.

Images