CN106787626B - Slope compensation circuit and power conversion device - Google Patents
Slope compensation circuit and power conversion device Download PDFInfo
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- CN106787626B CN106787626B CN201710019078.1A CN201710019078A CN106787626B CN 106787626 B CN106787626 B CN 106787626B CN 201710019078 A CN201710019078 A CN 201710019078A CN 106787626 B CN106787626 B CN 106787626B
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 77
- 238000005070 sampling Methods 0.000 claims abstract description 78
- 239000003990 capacitor Substances 0.000 claims description 31
- 230000000694 effects Effects 0.000 abstract description 5
- 230000005669 field effect Effects 0.000 description 26
- 238000010586 diagram Methods 0.000 description 8
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0009—Devices or circuits for detecting current in a converter
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
Abstract
Disclosed is a slope compensation circuit including: the voltage-to-current conversion module is used for generating a slope compensation current signal according to the input voltage; the slope compensation module is used for generating a slope compensation voltage signal according to the slope compensation current signal and compensating the sampling current signal according to the slope compensation voltage signal; the output end of the voltage-to-current conversion module is connected with the input end and the output end of the slope compensation module, and the sampling current signal is compensated in a voltage superposition mode. According to the slope compensation circuit and the power conversion device provided by the embodiment of the invention, the sampling current signal is compensated in a voltage superposition mode by converting the slope compensation current signal into the slope compensation voltage signal. According to the embodiment of the invention, the use of the amplifier is reduced, so that the occupied area of the circuit is reduced, and the sampling current signal is compensated in a voltage superposition mode, so that the requirement of the circuit on current is smaller, and the same slope compensation effect can be realized by adjusting the capacitance value.
Description
Technical Field
The invention belongs to the technical field of integrated circuits, and particularly relates to a slope compensation circuit and a power conversion device.
Background
The DC-DC switching power supply controlled by the current mode is adopted, and a loop for current sampling is added on the basis of traditional voltage mode control, so that the dynamic characteristic of the DC-DC system is obviously enhanced. The current mode control is classified into peak current mode control and valley current mode control according to different feedback loop designs. However, subharmonic oscillation occurs in the DC-DC system in either the peak current mode with an operating duty cycle greater than 50% or the valley current mode with an operating duty cycle less than 50%. It is therefore necessary to add a slope compensation circuit in the loop of the current sample to achieve good stability of the current loop.
Fig. 1 shows a block diagram of a power conversion device according to the prior art. As shown in fig. 1, the power conversion apparatus includes a power conversion circuit 10, a current sampling circuit 20, a slope compensation circuit 30, a control circuit 40, and a load circuit 50. The power conversion circuit 10 includes an input voltage terminal Vin, an output voltage terminal Vout, a first power switching tube M1, a second power switching tube M2, and an inductance L, where the inductance L and the first power switching tube M1 are connected in series between the input voltage terminal Vin and the output voltage terminal Vout; the second power switch tube M2 is connected between the node between the inductor L and the first power switch tube M1 and the ground GND. The current sampling circuit 20 obtains a sampling current signal Is from the power conversion circuit 10, and compensates the sampling current signal Is through the slope compensation circuit 30 to obtain a compensated sampling voltage signal Vramp; the control circuit 40 generates a PWM signal (pulse width modulation signal) according to the compensated sampling voltage signal Vc to control the on and off of the first power switching transistor M1 and the second power switching transistor M2 in the power conversion circuit 10. Fig. 2 shows a schematic diagram of a slope compensation circuit according to the prior art. As shown in fig. 2, the slope compensation circuit 30 includes a voltage-to-current conversion module 31 and a slope compensation module 32, and can be applied to a power conversion device controlled by a valley current mode in a loop of current sampling. The voltage-to-current conversion module 31 includes a first amplifier A1, a first transistor Q1, a first resistor R1, a second transistor Q2, and a third transistor Q3. The first amplifier A1, the first transistor Q1, and the first resistor R1 form a voltage-to-current converting unit 311, and mirror the first current signal to the slope compensation module 32 through a mirror unit 312. The first input end of the first amplifier A1 inputs K-Vin, the second input end is connected with the ground end GND through the first resistor R1, and the output end is connected with the control electrode of the first transistor Q1; a first pole of the first transistor Q1 is connected with the ground end GND through a first resistor R1, and a second pole is connected with a control pole of the second transistor Q2, a second pole and a control pole of the third transistor Q3; first poles of the second transistor Q2 and the third transistor Q3 are connected to the first voltage Vdd, and a second pole of the third transistor outputs a first current signal. The slope compensation module 32 includes a capacitor C, a switch S1, a second amplifier A2, a fourth transistor Q4, and a second resistor R2 and a third resistor R3. The first current signal forms a slope compensation voltage Vc by charging and discharging the capacitor C, the second amplifier A2, the fourth transistor Q4, and the second resistor R2 form a voltage-to-current conversion unit to convert the slope compensation voltage Vc into a slope compensation current signal Ic, and then the slope compensation current signal Ic Is superimposed with the sampling current signal Is, and forms a compensated sampling voltage signal Vc through the third resistor R3. The switch S1 must be closed at a non-sampling time of each switching cycle, and resets the voltage value across the capacitor C. For the boost circuit of the valley current mode, the sampling time is the on time of the first power switch tube M1, so when the second power switch tube M2 is on, the switch S1 is closed. The first input end of the second amplifier A2 inputs K-Vin, the second input end is connected with the ground end GND through the first resistor R1, and the output end is connected with the control electrode of the fourth transistor Q4; the first pole of the fourth transistor Q4 Is connected to the ground GND through a first resistor R1, the second pole outputs a slope compensation current signal Ic and Is superimposed with the sampling current signal Is, and the third resistor R3 Is connected between the compensated sampling voltage signal Vramp and the ground GND.
The slope compensation circuit 30 uses two amplifiers, and has large occupied area and large power consumption; in order to achieve a suitable slope compensation effect, a larger slope compensation current is most likely to be generated on the second resistor R2, and the efficiency of the power conversion device is affected.
Disclosure of Invention
The invention aims to provide a slope compensation circuit and a power conversion device.
According to an aspect of the present invention, there is provided a slope compensation circuit including: the voltage-to-current conversion module is used for generating a slope compensation current signal according to the input voltage; the slope compensation module is used for generating a slope compensation voltage signal according to the slope compensation current signal and compensating the sampling current signal according to the slope compensation voltage signal; the output end of the voltage-to-current conversion module is connected with the input end and the output end of the slope compensation module, and the sampling current signal is compensated in a voltage superposition mode.
Preferably, the voltage-to-current conversion module comprises a voltage-to-current conversion unit and a first mirror image unit; the voltage-to-current conversion unit generates a slope compensation current signal according to the input voltage, and inputs the slope compensation current signal to the slope compensation module through the first mirror image unit.
Preferably, the voltage-to-current conversion unit includes a first amplifier, a first transistor, and a first resistor;
the first amplifier comprises a first input end, a second input end and an output end, wherein the first input end is used for receiving a first voltage signal, and the second input end is connected with the grounding end through a first resistor;
the control electrode of the first transistor is connected with the output end of the first amplifier, the first electrode is connected with the grounding end through the first resistor, and the second electrode is used for outputting a slope compensation current signal.
Preferably, the first mirror unit includes a second transistor and a third transistor,
wherein the control electrode of the second transistor is connected with the control electrode of the third transistor and is connected with the second electrode of the first transistor;
the second transistor is connected with the first pole of the third transistor and is connected with a second voltage;
the second pole of the second transistor is connected with the second pole of the first transistor;
the second pole of the third transistor outputs a slope compensation current signal;
preferably, the slope compensation module comprises a second mirroring unit and a slope compensation unit;
the second mirror image unit is connected with the voltage-to-current conversion module and is used for mirroring the slope compensation current signal to the slope compensation unit;
the slope compensation unit is used for generating a slope compensation voltage signal according to the slope compensation current signal and compensating the sampling current signal according to the slope compensation voltage signal.
Preferably, the second mirroring unit includes a fourth transistor and a fifth transistor;
wherein the control electrodes of the fourth transistor and the fifth transistor are connected and connected with the second electrode of the third transistor;
the first poles of the fourth transistor and the fifth transistor are connected with the ground terminal;
the second pole of the fourth transistor is connected with the second pole of the third transistor;
the second pole of the fifth transistor is connected with the input and output ends of the slope compensation unit.
Preferably, the slope compensation unit includes a capacitor, a switch, a second resistor and a third resistor,
the capacitor, the second resistor and the third resistor are connected in series between the input and output ends of the slope compensation unit and the ground end;
the switch is connected in parallel at two ends of the capacitor;
wherein the sampling current signal is connected to a node between the second resistor and the third resistor.
Preferably, the slope compensation module further comprises a bias current source connected to a node between the capacitor and the third resistor.
According to another aspect of the present invention, there is provided a power conversion apparatus including a power conversion circuit, a current sampling circuit, the above-described slope compensation circuit, and a control circuit,
the current sampling circuit acquires a sampling current signal from the power conversion circuit;
the slope compensation circuit compensates the sampling current signal in a voltage superposition mode;
the control circuit generates PWM signals according to the compensated sampling voltage signals, wherein the PWM signals are used for controlling the on and off of a power switch tube in the power conversion circuit.
Preferably, the power conversion circuit comprises an input voltage end, an output voltage end, a first power switch tube, a second power switch tube and an inductor, wherein the inductor and the first power switch tube are connected in series between the input voltage end and the output voltage end; the second power switch tube is connected between the node between the inductor and the first power switch tube and the grounding end.
Preferably, the current sampling circuit comprises a third switching tube, a fourth switching tube and an amplifier;
the control electrode of the third switching tube is connected with the control circuit and is used for receiving PWM signals, the first electrode is connected with a node between the inductor and the first power switching tube, and the second electrode is connected with the first electrode of the fourth switching tube;
the amplifier comprises a first input end, a second input end and an output end, wherein the first input end is connected with a second pole of the first power switching tube, the second input end is connected with a second pole of the third switching tube, and the output end is connected with a control pole of the fourth switching tube;
the controller of the fourth switching tube is connected with the output end of the amplifier, and the first pole is connected with the second pole of the third switching tube; the second pole outputs a sampling current signal.
Preferably, the power conversion device further comprises a load circuit,
the load circuit comprises a load capacitor, a first voltage dividing resistor, a second voltage dividing resistor and a load resistor;
the load capacitor and the load resistor are connected in parallel between an output voltage end and a grounding end;
the first voltage dividing resistor and the second voltage dividing resistor are connected in series between the output voltage terminal and the ground terminal.
Preferably, the control circuit is further connected to a node between the first voltage dividing resistor and the second voltage dividing resistor, and generates the PWM signal according to the voltage dividing signal and the ramp-compensated sampling voltage signal.
According to the slope compensation circuit and the power conversion device provided by the embodiment of the invention, the sampling current signal is compensated in a voltage superposition mode by converting the slope compensation current signal into the slope compensation voltage signal. According to the embodiment of the invention, the use of the amplifier is reduced, so that the occupied area of the circuit is reduced, and the sampling current signal is compensated in a voltage superposition mode, so that the requirement of the circuit on current is smaller, and the same slope compensation effect can be realized by adjusting the capacitance value.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings, in which:
fig. 1 shows a circuit diagram of a power conversion device according to the prior art;
fig. 2 shows a circuit diagram of a slope compensation circuit according to the prior art;
FIG. 3 shows a circuit diagram of a slope compensation circuit provided in accordance with an embodiment of the present invention;
fig. 4 shows a circuit diagram of a power conversion apparatus provided according to an embodiment of the present invention;
fig. 5 shows waveforms of a switching sequence, an inductor current, a sampling current signal, a slope compensation voltage and a compensated sampling voltage signal of the power conversion device according to the embodiment of the present invention.
Detailed Description
Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. The same reference numbers will be used throughout the drawings to refer to the same or like parts. For clarity, the various features of the drawings are not drawn to scale.
The invention may be embodied in various forms, some examples of which are described below.
Fig. 3 shows a circuit diagram of a slope compensation circuit provided according to an embodiment of the present invention. As shown in fig. 3, the slope compensation circuit 30 includes a voltage-to-current conversion module 31 and a slope compensation module 32, and can be applied to a power conversion device controlled by a valley current mode in a loop of current sampling.
The voltage-to-current conversion module 31 is configured to generate a slope compensation current signal Ic according to an input voltage Vin.
The slope compensation module 32 Is configured to generate a slope compensation voltage signal Vc according to the slope compensation current signal Ic, and to compensate the sampling current signal Is according to the slope compensation voltage signal Vc.
The output end of the voltage-to-current conversion module 31 Is connected to the input and output ends of the slope compensation module 32, and compensates the sampling current signal Is in a voltage superposition manner.
In this embodiment, the voltage-to-current conversion module 31 includes a voltage-to-current conversion unit 311 and a first mirror current 312. The voltage-to-current conversion unit 311 generates a slope compensation current signal Ic according to the input voltage Vin, and inputs the slope compensation current signal Ic to the slope compensation module 32 through the first mirroring unit 312.
The voltage-to-current conversion unit 311 includes a first amplifier A1, a first transistor Q1, and a first resistor R1. The first amplifier A1 includes a first input end, a second input end and an output end, wherein the first input end is used for receiving a first voltage signal k×vin, and the second input end is connected with the ground end GND through a first resistor R1; the control electrode of the first transistor Q1 is connected to the output terminal of the first amplifier A1, the first electrode is connected to the ground terminal through the first resistor R1, and the second electrode is used for outputting the slope compensation current signal ic=kvin/R1.
The first mirror unit 312 includes a second transistor Q2 and a third transistor Q3, wherein the control electrodes of the second transistor Q2 and the third transistor Q3 are connected to the second electrode of the first transistor Q1; the first poles of the second transistor Q2 and the third transistor Q3 are connected and connected to the second voltage Vdd; the second pole of the second transistor Q2 is connected with the second pole of the first transistor Q1; the second pole of the third transistor Q3 outputs the slope compensation current signal Ic.
The slope compensation module 32 includes a second mirroring unit 321 and a slope compensation unit 322. The second mirroring unit 321 is connected to the voltage-to-current conversion module 31, and is configured to mirror the slope compensation current signal Ic to the slope compensation unit 322; the slope compensation unit 322 is configured to generate a slope compensation voltage signal vc= -K Vin/(R1×c) according to the slope compensation current signal Ic, and compensate the sampling current signal Ic according to the slope compensation voltage signal Vc to obtain a compensated sampling voltage signal Vramp.
Wherein vramp= -K × Vin, (r2+r3)/r1+is × r2-K × Vin/(r1× C).
The second mirror unit 321 includes a fourth transistor Q4 and a fifth transistor Q5. Wherein the control electrodes of the fourth transistor Q4 and the fifth transistor Q5 are connected with the second electrode of the third transistor Q3; the first poles of the fourth transistor Q4 and the fifth transistor Q5 are connected to the ground GND; the second pole of the fourth transistor Q4 is connected to the second pole of the third transistor Q3; the second pole of the fifth transistor Q5 is connected to the input/output terminal Vramp of the slope compensation unit 322.
The slope compensation unit 322 includes a capacitor C, a switch S1, a second resistor R2, and a third resistor R3. The capacitor C, the second resistor R2 and the third resistor R3 are connected in series between the input/output terminal Vramp and the ground GND of the slope compensation unit 322; the switch S1 is connected in parallel to two ends of the capacitor C; wherein the sampling current signal Is connected to a node between the second resistor R2 and the third resistor R3.
In a first state, i.e. at the moment of non-sampling current, the switch S Is closed, where is=0, vramp= -k×vin (r2+r3)/R1, and the voltage vc=0 across the capacitor; in the second state, i.e. at the moment of sampling current, the switch S Is turned off, and at the same time, the sampling current signal Is injected, and the slope compensation current signal Ic discharges the capacitor C, i.e. vc= -K Vin/(R1C), vramp= -K Vin (r2+r3)/r1+is R2-K Vin/(R1C).
In a preferred embodiment, the slope compensation module 322 further includes a bias current source Ib connected to a node between the capacitor C and the third resistor R3. At this time, vramp= (Ib-K Vin/R1), (r2+r3) +is R2-K Vin/(r1×c).
The first transistor Q1, the fourth transistor Q4 and the fifth transistor Q5 are N-type transistors or field effect transistors, the first pole is an emitter of the transistor or a source of the field effect transistor, the second pole is a collector of the transistor or a drain of the field effect transistor, and the control is an emitter of the transistor or a gate of the field effect transistor.
The second transistor Q2 and the third transistor Q4 are P-type transistors or field effect transistors, the first pole is the emitter of the transistor or the source of the field effect transistor, the second pole is the collector of the transistor or the drain of the field effect transistor, and the control is the base of the transistor or the gate of the field effect transistor.
According to the slope compensation circuit provided by the embodiment of the invention, the sampling current signal is compensated in a voltage superposition mode by converting the slope compensation current signal into the slope compensation voltage signal. According to the embodiment of the invention, the use of the amplifier is reduced, so that the occupied area of the circuit is reduced, and the sampling current signal is compensated in a voltage superposition mode, so that the requirement of the circuit on current is smaller, and the same slope compensation effect can be realized by adjusting the capacitance value.
Fig. 4 shows a circuit diagram of a power conversion device provided according to an embodiment of the present invention. As shown in fig. 4, the power conversion apparatus includes a power conversion circuit 10, a current sampling circuit 20, a slope compensation circuit 30, and a control circuit 40.
Wherein the current sampling circuit 20 obtains a sampling current signal Is from the power conversion circuit 10. The ramp compensation circuit 30 compensates the sampling current signal Is in a voltage superposition manner. The control circuit 40 generates a PWM signal according to the compensated sampling voltage signal Vramp, where the PWM signal is used to control on and off of a power switch tube in the power conversion circuit 10.
In this embodiment, the power conversion circuit 10 includes an input voltage terminal Vin, an output voltage terminal Vout, a first power switch M1, a second power switch M2, and an inductance L. The inductor L and the first power switch tube M1 are connected in series between an input voltage end Vin and an output voltage end Vout; the second power switch tube M2 is connected between the node between the inductor L and the first power switch tube M2 and the ground GND. The first power switch tube M1 is a P-type triode or a field effect transistor, and the second power switch tube M2 is an N-type triode or a field effect transistor; the first electrode is the emitter of the triode or the source electrode of the field effect transistor, the second electrode is the collector of the triode or the drain electrode of the field effect transistor, and the base electrode of the triode or the grid electrode of the field effect transistor is controlled.
The current sampling circuit 20 includes a third switching tube M3, a fourth switching tube M4, and a third amplifier OP; the control electrode of the third switching tube M3 is connected with the control circuit 40, and is used for receiving the PWM signal, the first electrode is connected with the node between the inductor L and the first power switching tube M1, and the second electrode is connected with the first electrode of the fourth switching tube M4; the third amplifier OP comprises a first input end, a second input end and an output end, wherein the first input end is connected with a second pole of the first power switching tube M1, the second input end is connected with a second pole of the third switching tube M3, and the output end is connected with a control pole of the fourth switching tube M4; the controller of the fourth switching tube M4 is connected with the output end of the third amplifier, and the first pole is connected with the second pole of the third switching tube M3; the second pole outputs a sampling current signal Is.
The third switch tube M3 is a P-type triode or a field effect transistor, and the fourth switch tube M4 is an N-type triode or a field effect transistor; the first electrode is the emitter of the triode or the source electrode of the field effect transistor, the second electrode is the collector of the triode or the drain electrode of the field effect transistor, and the base electrode of the triode or the grid electrode of the field effect transistor is controlled.
The slope compensation circuit 30 includes a voltage-to-current conversion module 31 and a slope compensation module 32.
The voltage-to-current conversion module 31 is configured to generate a slope compensation current signal Ic according to an input voltage Vin.
The slope compensation module 32 Is configured to generate a slope compensation voltage signal Vc according to the slope compensation current signal Ic, and to compensate the sampling current signal Is according to the slope compensation voltage signal Vc.
The output end of the voltage-to-current conversion module 31 Is connected to the input and output ends of the slope compensation module 32, and compensates the sampling current signal Is in a voltage superposition manner.
In this embodiment, the voltage-to-current conversion module 31 includes a voltage-to-current conversion unit 311 and a first mirror current 312. The voltage-to-current conversion unit 311 generates a slope compensation current signal Ic according to the input voltage Vin, and inputs the slope compensation current signal Ic to the slope compensation module 32 through the first mirroring unit 312.
The voltage-to-current conversion unit 311 includes a first amplifier A1, a first transistor Q1, and a first resistor R1. The first amplifier A1 includes a first input end, a second input end and an output end, wherein the first input end is used for receiving a first voltage signal k×vin, and the second input end is connected with the ground end GND through a first resistor R1; the control electrode of the first transistor Q1 is connected to the output terminal of the first amplifier A1, the first electrode is connected to the ground terminal through the first resistor R1, and the second electrode is used for outputting the slope compensation current signal ic=kvin/R1.
The first mirror unit 312 includes a second transistor Q2 and a third transistor Q3, wherein the control electrodes of the second transistor Q2 and the third transistor Q3 are connected to the second electrode of the first transistor Q1; the first poles of the second transistor Q2 and the third transistor Q3 are connected and connected to the second voltage Vdd; the second pole of the second transistor Q2 is connected with the second pole of the first transistor Q1; the second pole of the third transistor Q3 outputs the slope compensation current signal Ic.
The slope compensation module 32 includes a second mirroring unit 321 and a slope compensation unit 322. The second mirroring unit 321 is connected to the voltage-to-current conversion module 31, and is configured to mirror the slope compensation current signal Ic to the slope compensation unit 322; the slope compensation unit 322 is configured to generate a slope compensation voltage signal vc= -K Vin/(R1×c) according to the slope compensation current signal Ic, and compensate the sampling current signal Ic according to the slope compensation voltage signal Vc to obtain a compensated sampling voltage signal Vramp.
Wherein vramp= -K × Vin, (r2+r3)/r1+is × r2-K × Vin/(r1× C).
The second mirror unit 321 includes a fourth transistor Q4 and a fifth transistor Q5. Wherein the control electrodes of the fourth transistor Q4 and the fifth transistor Q5 are connected with the second electrode of the third transistor Q3; the first poles of the fourth transistor Q4 and the fifth transistor Q5 are connected to the ground GND; the second pole of the fourth transistor Q4 is connected to the second pole of the third transistor Q3; the second pole of the fifth transistor Q5 is connected to the input/output terminal Vramp of the slope compensation unit 322.
The slope compensation unit 322 includes a capacitor C, a switch S1, a second resistor R2, and a third resistor R3. The capacitor C, the second resistor R2 and the third resistor R3 are connected in series between the input/output terminal Vramp and the ground GND of the slope compensation unit 322; the switch S1 is connected in parallel to two ends of the capacitor C; wherein the sampling current signal Is connected to a node between the second resistor R2 and the third resistor R3.
In a first state, i.e. at the moment of non-sampling current, the switch S Is closed, where is=0, vramp= -k×vin (r2+r3)/R1, and the voltage vc=0 across the capacitor; in the second state, i.e. at the moment of sampling current, the switch S Is turned off, and at the same time, the sampling current signal Is injected, and the slope compensation current signal Ic discharges the capacitor C, i.e. vc= -K Vin/(R1C), vramp= -K Vin (r2+r3)/r1+is R2-K Vin/(R1C).
In a preferred embodiment, the slope compensation module 322 further includes a bias current source Ib connected to a node between the capacitor C and the third resistor R3. At this time, vramp= (Ib-K Vin/R1), (r2+r3) +is R2-K Vin/(r1×c).
The first transistor Q1, the fourth transistor Q4 and the fifth transistor Q5 are N-type transistors or field effect transistors, the first pole is an emitter of the transistor or a source of the field effect transistor, the second pole is a collector of the transistor or a drain of the field effect transistor, and the control is an emitter of the transistor or a gate of the field effect transistor.
The second transistor Q2 and the third transistor Q4 are P-type transistors or field effect transistors, the first pole is the emitter of the transistor or the source of the field effect transistor, the second pole is the collector of the transistor or the drain of the field effect transistor, and the control is the base of the transistor or the gate of the field effect transistor.
The power conversion device further comprises a load circuit 50, wherein the load circuit 50 comprises a load capacitor Cload, a first voltage dividing resistor Ra, a second voltage dividing resistor Rb and a load resistor Rload; the load capacitor Cload and the load resistor Rload are connected in parallel between an output voltage end Vout and a ground end GND; the first voltage dividing resistor Ra and the second voltage dividing resistor Rb are connected in series between the output voltage terminal Vout and the ground terminal GND.
The control circuit 40 is further connected to a node between the first voltage dividing resistor Ra and the second voltage dividing resistor Rb, and generates a PWM signal according to the voltage dividing signal and the ramp-compensated sampling voltage signal Vramp.
Fig. 5 shows waveforms of a switching sequence, an inductor current, a sampling current signal, a slope compensation voltage and a compensated sampling voltage signal of the power conversion device according to the embodiment of the present invention. In the first state, when pwm=1, the first power switching tube M1 is turned on, the second power switching tube M2 is turned off, the inductor current IL rises, and the rising slope thereof is Vin/L; in the second state, pwm=0, the first power switch M1 is turned off, the second power switch M2 is turned on, and the inductor current IL decreases with a decreasing slope of (Vout-Vin)/L. Inductor current IL Is sampled as Is by a factor K.
In the first state, pwm=1, which is the non-current sampling time, switch S1 is closed, and the voltage across capacitor C is reset to 0; in the second state, pwm=0, and for the current sampling time, the switch S1 is turned off, and the slope compensation current Ic discharges the capacitor C.
According to the power conversion device provided by the embodiment of the invention, the sampling current signal is compensated in a voltage superposition mode by converting the slope compensation current signal into the slope compensation voltage signal. According to the embodiment of the invention, the use of the amplifier is reduced, so that the occupied area of the circuit is reduced, and the sampling current signal is compensated in a voltage superposition mode, so that the requirement of the circuit on current is smaller, and the same slope compensation effect can be realized by adjusting the capacitance value.
Embodiments in accordance with the present invention, as described above, are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various modifications as are suited to the particular use contemplated. The scope of the invention should be determined by the following claims.
Claims (11)
1. A slope compensation circuit, comprising:
the voltage-to-current conversion module is used for generating a slope compensation current signal according to the input voltage;
the slope compensation module is used for generating a slope compensation voltage signal according to the slope compensation current signal and compensating the sampling current signal according to the slope compensation voltage signal;
wherein the output end of the voltage-to-current conversion module is connected with the input and output ends of the slope compensation module to compensate the sampling current signal in a voltage superposition mode,
the slope compensation module comprises a second mirror image unit and a slope compensation unit;
the second mirror image unit is connected with the voltage-to-current conversion module and is used for mirroring the slope compensation current signal to the slope compensation unit;
the slope compensation unit is used for generating a slope compensation voltage signal according to the slope compensation current signal and compensating the sampling current signal according to the slope compensation voltage signal, and comprises a capacitor, a switch, a second resistor and a third resistor, wherein the capacitor, the second resistor and the third resistor are connected in series between an input end and an output end of the slope compensation unit and a grounding end; the switch is connected in parallel at two ends of the capacitor; the sampling current signal is connected with a node between the second resistor and the third resistor.
2. The slope compensation circuit of claim 1, wherein the voltage-to-current conversion module comprises a voltage-to-current conversion unit and a first mirroring unit;
the voltage-to-current conversion unit generates a slope compensation current signal according to the input voltage, and inputs the slope compensation current signal to the slope compensation module through the first mirror image unit.
3. The slope compensation circuit of claim 2, wherein the voltage to current conversion unit comprises a first amplifier, a first transistor, and a first resistor;
the first amplifier comprises a first input end, a second input end and an output end, wherein the first input end is used for receiving a first voltage signal, and the second input end is connected with the grounding end through a first resistor;
the control electrode of the first transistor is connected with the output end of the first amplifier, the first electrode is connected with the grounding end through the first resistor, and the second electrode is used for outputting a slope compensation current signal.
4. The slope compensation circuit of claim 3, wherein the first mirror unit comprises a second transistor and a third transistor,
wherein the control electrode of the second transistor is connected with the control electrode of the third transistor and is connected with the second electrode of the first transistor;
the second transistor is connected with the first pole of the third transistor and is connected with a second voltage;
the second pole of the second transistor is connected with the second pole of the first transistor;
the second pole of the third transistor outputs a slope compensation current signal.
5. The slope compensation circuit of claim 4, wherein the second mirror unit comprises a fourth transistor and a fifth transistor;
wherein the control electrodes of the fourth transistor and the fifth transistor are connected and connected with the second electrode of the third transistor;
the first poles of the fourth transistor and the fifth transistor are connected with the ground terminal;
the second pole of the fourth transistor is connected with the second pole of the third transistor;
the second pole of the fifth transistor is connected with the input and output ends of the slope compensation unit.
6. The slope compensation circuit of claim 4, wherein the slope compensation module further comprises a bias current source connected to a node between the capacitor and the third resistor.
7. A power conversion apparatus comprising a power conversion circuit, a current sampling circuit, a slope compensation circuit according to any one of claims 1 to 6, and a control circuit,
the current sampling circuit acquires a sampling current signal from the power conversion circuit;
the slope compensation circuit compensates the sampling current signal in a voltage superposition mode;
the control circuit generates PWM signals according to the compensated sampling voltage signals, wherein the PWM signals are used for controlling the on and off of a power switch tube in the power conversion circuit.
8. The power conversion device of claim 7, wherein the power conversion circuit comprises an input voltage terminal, an output voltage terminal, a first power switching tube, a second power switching tube, and an inductor, wherein the inductor and the first power switching tube are connected in series between the input voltage terminal and the output voltage terminal; the second power switch tube is connected between the node between the inductor and the first power switch tube and the grounding end.
9. The power conversion device of claim 8, wherein the current sampling circuit comprises a third switching tube, a fourth switching tube, and an amplifier;
the control electrode of the third switching tube is connected with the control circuit and is used for receiving PWM signals, the first electrode is connected with a node between the inductor and the first power switching tube, and the second electrode is connected with the first electrode of the fourth switching tube;
the amplifier comprises a first input end, a second input end and an output end, wherein the first input end is connected with a second pole of the first power switching tube, the second input end is connected with a second pole of the third switching tube, and the output end is connected with a control pole of the fourth switching tube;
the control electrode of the fourth switching tube is connected with the output end of the amplifier, and the first electrode is connected with the second electrode of the third switching tube; the second pole outputs a sampling current signal.
10. The power conversion device of claim 7, further comprising a load circuit,
the load circuit comprises a load capacitor, a first voltage dividing resistor, a second voltage dividing resistor and a load resistor;
the load capacitor and the load resistor are connected in parallel between an output voltage end and a grounding end;
the first voltage dividing resistor and the second voltage dividing resistor are connected in series between the output voltage terminal and the ground terminal.
11. The power conversion device according to claim 10, wherein the control circuit is further connected to a node between the first voltage dividing resistor and the second voltage dividing resistor, and generates the PWM signal based on the voltage dividing signal and the ramp-compensated sampled voltage signal.
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| CN107844154B (en) * | 2017-08-31 | 2023-07-21 | 北京集创北方科技股份有限公司 | Voltage stabilizing circuit |
| CN111596716A (en) * | 2020-05-29 | 2020-08-28 | 北京集创北方科技股份有限公司 | Voltage adjusting device, chip, power supply and electronic equipment |
| CN111596715A (en) * | 2020-05-29 | 2020-08-28 | 北京集创北方科技股份有限公司 | Voltage adjusting device, chip, power supply and electronic equipment |
| CN112104231B (en) * | 2020-09-18 | 2022-03-22 | 上海艾为电子技术股份有限公司 | Slope compensation circuit, method for generating slope compensation current and converter |
| CN112383725B (en) * | 2020-11-13 | 2023-05-05 | 成都微光集电科技有限公司 | Ramp signal generating circuit and method, CMOS image sensor and readout circuit thereof |
| CN112752044B (en) * | 2020-12-30 | 2022-11-04 | 成都微光集电科技有限公司 | Ramp generator, pixel column readout circuit and image sensor |
| CN117118206B (en) * | 2023-10-08 | 2024-01-26 | 深圳市微源半导体股份有限公司 | Current generating circuit, switching converter and switching power supply |
| CN117792093B (en) * | 2024-02-27 | 2024-05-17 | 上海芯龙半导体技术股份有限公司 | Slope compensation and comparator circuit |
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