CN116436275B - Voltage conversion circuit and voltage conversion chip - Google Patents
Voltage conversion circuit and voltage conversion chip Download PDFInfo
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- CN116436275B CN116436275B CN202310686211.4A CN202310686211A CN116436275B CN 116436275 B CN116436275 B CN 116436275B CN 202310686211 A CN202310686211 A CN 202310686211A CN 116436275 B CN116436275 B CN 116436275B
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 184
- 230000033228 biological regulation Effects 0.000 claims abstract description 30
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- 239000003990 capacitor Substances 0.000 claims description 10
- 230000001276 controlling effect Effects 0.000 claims description 2
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- 230000000875 corresponding effect Effects 0.000 description 6
- 102100036285 25-hydroxyvitamin D-1 alpha hydroxylase, mitochondrial Human genes 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
- H02M1/32—Means for protecting converters other than automatic disconnection
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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
- H02M1/32—Means for protecting converters other than automatic disconnection
- H02M1/327—Means for protecting converters other than automatic disconnection against abnormal temperatures
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
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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)
- Dc-Dc Converters (AREA)
Abstract
The invention discloses a voltage conversion circuit and a voltage conversion chip. The voltage conversion circuit comprises an under-voltage protection unit; the under-voltage protection unit comprises a current regulation module, a positive temperature coefficient module and a signal conversion module; the first end of the current regulating module and the first end of the signal converting module are connected with the power switch tube, the second end of the current regulating module is connected with the first end of the positive temperature coefficient module, the output end of the current regulating module and the output end of the positive temperature coefficient module are connected with the control end of the signal converting module, and the second end of the positive temperature coefficient module is connected with the first potential end; the current regulation module is used for regulating a current signal flowing through the positive temperature coefficient module according to the conversion voltage, the positive temperature coefficient module is used for regulating the control end potential of the signal conversion module according to the current signal and the temperature, and the signal conversion module is used for outputting an under-voltage protection signal when the control end potential is smaller than or equal to the conversion threshold voltage; the stability of the undervoltage protection threshold voltage of the undervoltage protection unit can be improved.
Description
Technical Field
The embodiment of the invention relates to the technical field of voltage conversion, in particular to a voltage conversion circuit and a voltage conversion chip.
Background
The voltage conversion circuit may convert an input voltage into a voltage of other potential, thereby providing an operating voltage for other circuits. For example, the dc voltage conversion circuit may convert an input dc voltage to a dc voltage of a desired magnitude to provide a desired operating voltage for other circuits. The voltage conversion circuit may include an under-voltage protection circuit for providing an under-voltage protection signal when an input voltage of the voltage conversion circuit drops to a voltage, so that an under-voltage protection action of the voltage conversion circuit may be realized. When the input voltage of the voltage conversion circuit is under-voltage, the output voltage of the voltage conversion circuit is reduced. The under-voltage protection circuit can judge whether the input voltage drops to a voltage according to the required voltage output by the voltage conversion circuit so as to perform under-voltage protection. The undervoltage protection circuit may include a comparator, and when the undervoltage protection circuit determines the required voltage, a threshold voltage needs to be set to implement a comparison and determination process. At this time, one input end of the comparator is used for inputting a threshold voltage, and the other input end is used for inputting a voltage corresponding to a required voltage. The threshold voltage may be a voltage of one input end of the comparator corresponding to the input voltage when the undervoltage protection circuit needs to perform undervoltage protection according to the voltage drop of the input voltage to the voltage, so that when the voltage corresponding to the required voltage is input to the other input end of the comparator, the comparison signal output by the comparator can realize jump.
In the related art, a required voltage output from a voltage conversion circuit is positively correlated with temperature, and the higher the temperature is, the greater the required voltage is output. Under the condition that the threshold voltage is unchanged, the output voltage of the voltage conversion circuit is reduced to the voltage of the undervoltage protection circuit outputting the undervoltage protection signal at high temperature, and the voltage is different from the voltage of the undervoltage protection circuit outputting the undervoltage protection signal at low temperature, so that the stability of the undervoltage protection threshold voltage of the undervoltage protection circuit is reduced.
Disclosure of Invention
The invention provides a voltage conversion circuit and a voltage conversion chip, which are used for improving the stability of an undervoltage protection threshold voltage of an undervoltage protection circuit.
In a first aspect, an embodiment of the present invention provides a voltage conversion circuit, including a voltage conversion unit, an under-voltage protection unit, and a control unit;
the voltage conversion unit comprises an input module and a power switch tube, wherein the input module is used for converting input voltage into first voltage; the power switch tube is connected with the input module and is used for outputting a conversion voltage according to the first voltage;
the under-voltage protection unit comprises a current regulation module, a positive temperature coefficient module and a signal conversion module; the first end of the current regulating module and the first end of the signal conversion module are connected with the power switch tube, the second end of the current regulating module is connected with the first end of the positive temperature coefficient module, the output end of the current regulating module and the output end of the positive temperature coefficient module are connected with the control end of the signal conversion module, and the second end of the positive temperature coefficient module is connected with the first potential end; the current regulation module is used for regulating a current signal flowing through the positive temperature coefficient module according to the conversion voltage, the positive temperature coefficient module is used for regulating the control end potential of the signal conversion module according to the current signal and the temperature, and the signal conversion module is used for outputting an under-voltage protection signal when the control end potential is smaller than or equal to the conversion threshold voltage;
The control unit is connected with the signal conversion module and is used for controlling the voltage conversion unit to perform under-voltage protection according to the under-voltage protection signal.
Optionally, the positive temperature coefficient module comprises a first switch tube, a second switch tube, a first resistor and a second resistor;
the control electrode of the first switching tube and the control electrode of the second switching tube are connected with the bias current input end, the first electrode of the first switching tube is connected with the second end of the current regulating module, the first electrode of the second switching tube is connected with the output end of the current regulating module through the second resistor, the second electrode of the second switching tube is connected with the second electrode of the first switching tube through the first resistor, and the second electrode of the first switching tube is connected with the first potential end.
Optionally, the current regulation module comprises a current mirror; the current mirror comprises a main body branch and a mirror image branch; the main body branch is connected between the power switch tube and a first pole of the first switch tube, and the mirror image branch is connected between the power switch tube and the second resistor; the main body branch circuit is used for forming mirror current according to the conversion voltage and the first pole current of the first switching tube, and the mirror branch circuit is used for mirroring the mirror current.
Optionally, the body branch includes a first transistor, and the mirror branch includes a second transistor;
the first pole of the first transistor and the first pole of the second transistor are connected with the power switch, the second pole of the first transistor, the grid of the first transistor and the grid of the second transistor are connected with the first pole of the first switch, and the second pole of the second transistor is connected with the second resistor.
Optionally, the signal conversion module includes a third transistor and a third resistor;
the grid electrode of the third transistor is connected with the output end of the current regulating module and the output end of the positive temperature coefficient module, the first electrode of the third transistor is connected with the power switch transistor, the second electrode of the third transistor is connected with the first end of the third resistor and serves as the output end of the signal converting module, and the second end of the third resistor is connected with the first potential end.
Optionally, the positive temperature coefficient module further comprises a fourth resistor; the second pole of the first switching tube is connected with the first potential end through the fourth resistor.
Optionally, the under-voltage protection unit further comprises a bias current generation module;
The first input end of the bias current generating module is connected with the power switch tube, the second input end of the bias current generating module is connected with the first potential end, and the output end of the bias current generating module is used as the bias current input end; the bias current generation module is used for forming bias current according to the conversion voltage and the first potential provided by the first potential end.
Optionally, the bias current generating module includes a fourth resistor, a fifth resistor, and a sixth resistor;
the first end of the fourth resistor is connected with the power switch tube, the second end of the fourth resistor is connected with the first end of the fifth resistor and the first end of the sixth resistor, the second end of the fifth resistor is connected with the first potential end, and the second end of the sixth resistor is used as an output end of the bias current generation module.
Optionally, the input module comprises a voltage division sub-module and a voltage stabilizing sub-module;
the input end of the voltage division submodule is used for being connected with the input voltage, the output end of the voltage division submodule is connected with the voltage stabilizing submodule, the voltage division submodule is used for converting the input voltage into the first voltage, and the voltage stabilizing submodule is used for stabilizing the first voltage; the control pole of the power switch tube is connected with the voltage stabilizing submodule, the first pole of the power switch tube is connected with the power input end, and the second pole of the power switch tube is used as the output end of the voltage conversion unit; the power switching tube is used for outputting the conversion voltage according to the first voltage.
In a second aspect, an embodiment of the present invention further provides a voltage conversion chip, including the voltage conversion circuit in the first aspect.
According to the technical scheme provided by the embodiment of the invention, the threshold voltage of the power switch tube is inversely related to the temperature. The under-voltage protection unit is provided with a current adjusting module, a positive temperature coefficient module and a signal conversion module. When the temperature rises, the switching voltage provided by the power switch tube increases to increase the first end potential of the current regulating module. And meanwhile, the current of the positive temperature coefficient module is increased to increase the second end potential of the current regulating module. Therefore, the pressure difference change at two ends of the current regulating module, which is caused by the negative temperature coefficient characteristic of the power switch tube, can be relieved through the positive temperature coefficient module at different temperatures. When the input voltage is reduced to the undervoltage protection threshold voltage, the voltage difference between two ends of the current regulation module is less than or equal to a threshold voltage, so that a current signal provided by the current regulation module is reduced, the potential of the output end of the positive temperature coefficient module is less than or equal to the conversion threshold voltage, and the signal conversion module outputs an undervoltage protection signal according to the potential of the control end. Namely, under different temperatures, the signal conversion module outputs a conversion voltage when the input voltage drops to the undervoltage protection threshold voltage and is used as an undervoltage protection signal. The control unit controls the voltage conversion unit to perform under-voltage protection according to the under-voltage protection signal, so that the voltage conversion unit realizes under-voltage protection. Therefore, the stability of the undervoltage protection threshold voltage of the undervoltage protection unit can be improved.
Drawings
Fig. 1 is a schematic structural diagram of a voltage conversion system according to the related art;
fig. 2 is a schematic diagram of a voltage conversion circuit according to the related art;
FIG. 3 is a schematic diagram of an under-voltage protection circuit according to the related art;
FIG. 4 is a schematic diagram showing the relationship between the voltage and the temperature when the input voltage is under-voltage and the under-voltage protection circuit outputs the under-voltage protection signal according to the related art;
fig. 5 is a schematic structural diagram of a voltage conversion circuit according to an embodiment of the present invention;
fig. 6 is a schematic diagram of another voltage conversion circuit according to an embodiment of the present invention;
fig. 7 is a schematic diagram of another voltage conversion circuit according to an embodiment of the present invention;
fig. 8 is a schematic diagram of another voltage conversion circuit according to an embodiment of the present invention;
fig. 9 is a schematic diagram of another voltage conversion circuit according to an embodiment of the present invention;
fig. 10 is a schematic diagram of another voltage conversion circuit according to an embodiment of the invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
Fig. 1 is a schematic diagram of a voltage conversion system according to the related art, fig. 2 is a schematic diagram of a voltage conversion circuit according to the related art, and fig. 3 is a schematic diagram of an under-voltage protection circuit according to the related art. As shown in fig. 1 to 3, the voltage conversion system includes a voltage conversion circuit prodio and an under-voltage protection circuit UVLO; the voltage conversion circuit proIdo converts the input voltage Vin into a required voltage vdd a to provide power for other circuits and the under-voltage protection circuit UVLO. Meanwhile, the UVLO outputs the voltage to the positive phase input end+ of the comparator comp after dividing the required voltage vdd a through the dividing resistor, the negative phase input end-of the comparator comp is connected with the threshold voltage, when the input voltage Vin is larger, the required voltage vdd output by the voltage conversion circuit prodio is larger, the voltage to the positive phase input end+ of the comparator comp is larger than the threshold voltage after dividing the required voltage vdd through the dividing resistor, the comparator comp outputs high level, and at the moment, the UVLO of the UVLO cannot output an undervoltage protection signal. When the input voltage Vin is smaller, the required voltage vdd a output by the voltage conversion circuit prodio is smaller, after the required voltage vdd a is divided by the voltage dividing resistor, the voltage output to the positive input end+ of the comparator comp is smaller than or equal to the threshold voltage, and the comparator comp outputs a low level, and at the moment, the undervoltage protection circuit UVLO outputs an undervoltage protection signal for realizing undervoltage protection of the voltage conversion circuit prodio. For example, when the input voltage Vin is 12V, the required voltage vdd a output by the voltage conversion circuit prodio may be 4.5V, and then divided by the dividing resistor so that the voltage +input to the positive phase input terminal of the comparator comp may be 2V, and the threshold voltage-input to the negative phase input terminal of the comparator comp may be 1.9V, at which time the comparator comp outputs a high level signal. The voltage conversion circuit proIdo comprises a voltage stabilizing tube DT1, when the input voltage Vin is reduced from 12V under voltage to 4.8V, the required voltage vdd a output by the voltage conversion circuit proIdo can be reduced from 4.5V to 4.1V, and then divided by a voltage dividing resistor, so that the voltage of the positive input end plus input of the comparator comp can be 1.89V, and the comparator comp outputs a low-level signal, namely an under-voltage protection signal, for realizing the under-voltage protection of the voltage conversion circuit proIdo.
With continued reference to fig. 1-3, the voltage conversion circuit prodio includes a power switching device M1, which is a negative temperature coefficient device. The required voltage vdd a output by the voltage conversion circuit prodio is the difference between the voltage divided by the voltage regulator DT1 and the threshold voltage of the power switching device M1. For example, the voltage after voltage division through the voltage regulator DT1 may be 5.8V, the threshold voltage of the power switch device M1 may be 1.3V, and the required voltage vdd a output by the voltage conversion circuit prodio is 4.5V. Along with the temperature rise, the threshold voltage of the power switch device M1 is reduced, so that the required voltage vdd a output by the voltage conversion circuit prodio is increased, and the under-voltage protection can be realized only when the input voltage Vin is reduced to be lower, thereby affecting the accuracy of the under-voltage protection circuit. For example, on the basis of the above example, at a high temperature, when the input voltage Vin is 12V, the required voltage vdd a output by the voltage conversion circuit prodmo may be 5V, and then divided by the voltage dividing resistor, so that the voltage of the positive phase input terminal + input of the comparator comp may be 2.5V, and the threshold voltage of the negative phase input terminal-access of the comparator comp may be 1.9V, at which time the comparator comp outputs a high level signal. When the input voltage Vin is reduced from 12V under voltage to 4.5V, the required voltage vdd a output by the voltage conversion circuit prodmo is reduced from 5V to 4.1V, and then voltage division is performed through a voltage dividing resistor, so that the voltage +input at the positive input end of the comparator comp can be 1.89V, and at the moment, the comparator comp outputs a low-level signal, namely an under-voltage protection signal, so that the under-voltage protection of the voltage conversion circuit prodmo is realized. Therefore, when the undervoltage protection circuit UVLO outputs an undervoltage protection signal for realizing the undervoltage protection of the voltage conversion circuit proIdo at different temperatures, the input voltage Vin is reduced from 12V undervoltage to different voltages, and the undervoltage protection accuracy of the undervoltage protection circuit is reduced. Fig. 4 is a schematic diagram of a relationship between voltage and temperature corresponding to an input voltage under-voltage to under-voltage protection circuit outputting an under-voltage protection signal according to the related art. The abscissa is the temperature (temp), and the ordinate is the voltage (V) corresponding to the undervoltage of the input voltage to the undervoltage protection circuit when the undervoltage protection circuit outputs the undervoltage protection signal. As shown in fig. 4, the higher the temperature, the smaller the corresponding voltage is when the input voltage is undervoltage to the undervoltage protection circuit outputs the undervoltage protection signal, i.e. the stability of the undervoltage protection threshold voltage is poor.
Aiming at the technical problems, the embodiment of the invention provides a voltage conversion circuit. Fig. 5 is a schematic structural diagram of a voltage conversion circuit according to an embodiment of the present invention. As shown in fig. 5, the voltage conversion circuit includes a voltage conversion unit 110, an under-voltage protection unit 120, and a control unit 130; the voltage conversion unit 110 includes an input module 111 and a power switch tube 112, wherein the input module 111 is used for converting an input voltage vin into a first voltage; the power switch tube 112 is connected with the input module 111, and the power switch tube 112 is used for outputting a conversion voltage vdd according to the first voltage; the under-voltage protection unit 120 includes a current adjustment module 121, a positive temperature coefficient module 122, and a signal conversion module 123; the first end of the current regulation module 121 and the first end of the signal conversion module 123 are connected with the power switch tube 112, the second end of the current regulation module 121 is connected with the first end of the positive temperature coefficient module 122, the output end of the current regulation module 121 and the output end of the positive temperature coefficient module 122 are connected with the control end of the signal conversion module 123, and the second end of the positive temperature coefficient module 122 is connected with the first potential end V1; the current adjusting module 121 is configured to adjust a current signal flowing through the positive temperature coefficient module 122 according to the conversion voltage vdd, the positive temperature coefficient module 122 is configured to adjust a control terminal potential of the signal converting module 123 according to the current signal and the temperature, and the signal converting module 123 is configured to output an under-voltage protection signal when the control terminal potential is less than or equal to a conversion threshold voltage; the control unit 130 is connected to the signal conversion module 123, and the control unit 130 is configured to control the voltage conversion unit 110 to perform an under-voltage protection operation according to the under-voltage protection signal.
Specifically, the input module 111 converts the input voltage vin to a first voltage, and outputs the first voltage to a control electrode of the power switch tube 112, where the first electrode of the power switch tube 112 is connected to a power source, for example, as shown in fig. 5, the first electrode of the power switch tube 112 is used for switching in the input voltage vin. The second pole of the power switch 112 serves as the output terminal VDD1 of the voltage converting unit 110. After the input module 111 outputs the first voltage, the power switch 112 subtracts the threshold voltage of the power switch 112 from the first voltage and outputs the subtracted voltage as the converted voltage vdd. When the input voltage vin decreases, the switching voltage vdd decreases with the input voltage vin. In addition, when the temperature rises, the threshold voltage of the power switch 112 decreases so that the switching voltage vdd increases when the first voltage is unchanged.
In operation, under normal temperature conditions, when the input voltage vin gradually decreases, the switching voltage vdd decreases with the decrease of the input voltage vin, the voltage difference across the current regulation module 121 decreases, and when the voltage difference across the current regulation module 121 is less than or equal to a threshold voltage, the current signal provided by the current regulation module 121 decreases, i.e. the current signal flowing through the ptc module 122 decreases. In the case where the parameters of the ptc block 122 are unchanged, the potential of the output of the ptc block 122 decreases. Before the input voltage vin drops to the undervoltage protection threshold voltage, the voltage difference between two ends of the current regulation module 121 is greater than a threshold voltage, the current signal provided by the current regulation module 121 is unchanged, the potential of the output end of the positive temperature coefficient module 122 is greater than the conversion threshold voltage, the signal conversion module 123 outputs a low-level signal according to the potential of the control end, and at this time, the control unit does not act according to the low-level signal, i.e. the voltage conversion unit 110 does not perform the undervoltage protection action. When the input voltage vin drops to the undervoltage protection threshold voltage, the voltage difference across the current adjustment module 121 is smaller than or equal to a threshold voltage, the current signal provided by the current adjustment module 121 decreases, the output terminal potential of the positive temperature coefficient module 122 is smaller than or equal to the conversion threshold voltage, and the signal conversion module 123 outputs the conversion voltage vdd according to the control terminal potential, that is, the high level, as the undervoltage protection signal. At this time, the signal output by the signal conversion module 123 jumps from low level to high level, and the control unit 130 controls the voltage conversion unit 110 to perform the under-voltage protection according to the under-voltage protection signal, so that the voltage conversion unit 110 realizes the under-voltage protection. Wherein, when the input voltage vin is under-voltage to the under-voltage protection threshold voltage, the under-voltage protection unit 120 forms an under-voltage protection signal. The switching threshold voltage corresponds to the under-voltage protection threshold voltage, that is, when the input voltage vin drops to the under-voltage protection threshold voltage, the output voltage of the ptc module 122 may be equal to the switching threshold voltage.
For example, at normal temperature, when the input voltage vin is 12V, the switching voltage vdd output by the power switch 112 may be 4.5V, at this time, the voltage difference across the current adjusting module 121 is greater than a threshold voltage, the current signal provided by the current adjusting module 121 is unchanged, the voltage at the output end of the positive temperature coefficient module 122 is greater than the switching threshold voltage, the signal converting module 123 outputs a low-level signal according to the control end potential, and at this time, the control unit does not act according to the low-level signal, that is, the voltage converting unit 110 does not perform the under-voltage protection action. When the undervoltage protection threshold voltage is 4.8V and the input voltage vin is reduced to 4.8V, the switching voltage vdd output by the power switch 112 may be reduced from 4.5V to 4.1V, and the voltage difference across the current regulation module 121 is reduced, so that the voltage difference across the current regulation module 121 is less than or equal to a threshold voltage, and the current signal provided by the current regulation module 121 is reduced, that is, the current signal flowing through the ptc module 122 is reduced. Under the condition that the parameters of the positive temperature coefficient module 122 are unchanged, the potential of the output end of the positive temperature coefficient module 122 drops to the conversion threshold voltage, and the signal conversion module 123 outputs the conversion voltage vdd according to the potential of the control end, namely, the high level is used as the under-voltage protection signal. At this time, the signal output by the signal conversion module 123 jumps from low level to high level, and the control unit 130 controls the voltage conversion unit 110 to perform the under-voltage protection according to the under-voltage protection signal, so that the voltage conversion unit 110 realizes the under-voltage protection.
Under high temperature conditions, the threshold voltage of the power switch 112 is reduced without considering the effect of the ptc block 122, such that the switching voltage vdd is increased when the first voltage is unchanged. When the input voltage vin drops to the undervoltage protection threshold voltage, the switching voltage vdd is relatively large, the voltage difference across the current regulation module 121 is greater than a threshold voltage, the current signal provided by the current regulation module 121 is unchanged, and the output terminal potential of the positive temperature coefficient module 122 is greater than the switching threshold voltage. When the input voltage vin decreases to be less than the undervoltage protection threshold voltage, until the voltage difference across the current regulation module 121 is less than or equal to a threshold voltage, the current signal provided by the current regulation module 121 decreases, and the output voltage of the positive temperature coefficient module 122 is less than or equal to the conversion threshold voltage. When considering the influence of the positive temperature coefficient module 122, the positive temperature coefficient module 122 can increase the current signal under the high temperature condition, and then can increase the second end potential of the current adjusting module 121, so as to relieve the pressure difference change at two ends of the current adjusting module 121 caused by the temperature change. When the input voltage vin gradually decreases, the voltage difference across the current adjustment module 121 may be smaller than or equal to a threshold voltage when the input voltage vin decreases to an undervoltage protection threshold voltage, the current signal provided by the current adjustment module 121 decreases, the potential of the output end of the positive temperature coefficient module 122 is smaller than or equal to a conversion threshold voltage, and the signal conversion module 123 outputs the conversion voltage vdd according to the potential of the control end, that is, a high level, and is used as an undervoltage protection signal. The voltage at the output end of the ptc block 122 at different temperatures may be less than or equal to the switching threshold voltage when the input voltage vin drops to the undervoltage protection threshold voltage, that is, the signal switching block 123 outputs the switching voltage vdd when the input voltage vin drops to the undervoltage protection threshold voltage at different temperatures and is used as the undervoltage protection signal. The control unit 130 controls the voltage conversion unit 110 to perform an under-voltage protection operation according to the under-voltage protection signal, so that the voltage conversion unit 110 realizes the under-voltage protection. Therefore, the stability of the undervoltage protection threshold voltage of the voltage conversion circuit can be improved.
For example, at a high temperature, when the input voltage vin is 12V, the switching voltage vdd output by the power switch 112 may rise from 4.5V to 5V, at this time, the voltage difference across the current adjusting module 121 is greater than a threshold voltage, the current signal provided by the current adjusting module 121 is unchanged, the voltage at the output end of the positive temperature coefficient module 122 is greater than the switching threshold voltage, the signal converting module 123 outputs a low level signal according to the potential of the control end, and at this time, the control unit does not act according to the low level signal, that is, the voltage converting unit 110 does not perform the under-voltage protection. When the undervoltage protection threshold voltage is 4.8V and the input voltage vin is understepped down to 4.8V, the switching voltage vdd output by the power switch 112 may be stepped down from 5V to xV, so that the first end potential of the current regulation module 121 increases relative to the 4.1V potential under the low temperature condition. Wherein x is greater than 4.1 and less than 5. Meanwhile, the positive temperature coefficient module 122 increases the current signal, so that the potential of the second end of the current adjusting module 121 can be increased, the voltage difference between two ends of the current adjusting module 121 is smaller than or equal to a threshold voltage, the current signal provided by the current adjusting module 121 is reduced, the potential of the output end of the positive temperature coefficient module 122 is smaller than or equal to a conversion threshold voltage, and the signal conversion module 123 outputs a conversion voltage vdd according to the potential of the control end, namely, the conversion voltage vdd is high level and is used as an under-voltage protection signal. The voltage at the output end of the ptc block 122 at different temperatures may be less than or equal to the switching threshold voltage when the input voltage vin drops to the undervoltage protection threshold voltage, that is, the signal switching block 123 outputs the switching voltage vdd when the input voltage vin drops to the undervoltage protection threshold voltage at different temperatures and is used as the undervoltage protection signal. The control unit 130 controls the voltage conversion unit 110 to perform an under-voltage protection operation according to the under-voltage protection signal, so that the voltage conversion unit 110 realizes the under-voltage protection.
According to the technical scheme of the embodiment, the threshold voltage of the power switch tube is inversely related to the temperature. The under-voltage protection unit is provided with a current adjusting module, a positive temperature coefficient module and a signal conversion module. When the temperature rises, the switching voltage provided by the power switch tube increases to increase the first end potential of the current regulating module. And meanwhile, the current of the positive temperature coefficient module is increased to increase the second end potential of the current regulating module. Therefore, the pressure difference change at two ends of the current regulating module, which is caused by the negative temperature coefficient characteristic of the power switch tube, can be relieved through the positive temperature coefficient module at different temperatures. When the input voltage is reduced to the undervoltage protection threshold voltage, the voltage difference between two ends of the current regulation module is less than or equal to a threshold voltage, so that a current signal provided by the current regulation module is reduced, the potential of the output end of the positive temperature coefficient module is less than or equal to the conversion threshold voltage, and the signal conversion module outputs an undervoltage protection signal according to the potential of the control end. Namely, under different temperatures, the signal conversion module outputs a conversion voltage when the input voltage drops to the undervoltage protection threshold voltage and is used as an undervoltage protection signal. The control unit controls the voltage conversion unit to perform under-voltage protection according to the under-voltage protection signal, so that the voltage conversion unit realizes under-voltage protection. Therefore, the stability of the undervoltage protection threshold voltage of the undervoltage protection unit can be improved.
Fig. 6 is a schematic diagram of another voltage conversion circuit according to an embodiment of the invention. As shown in fig. 6, the ptc block 122 includes a first switching tube Q1, a second switching tube Q2, a first resistor R1 and a second resistor R2; the control poles of the first switching tube Q1 and the second switching tube Q2 are connected with the bias current input end Ibs, the first pole of the first switching tube Q1 is connected with the second end of the current regulating module 121, the first pole of the second switching tube Q2 is connected with the output end of the current regulating module 121 through the second resistor R2, the second pole of the second switching tube Q2 is connected with the second pole of the first switching tube Q1 through the first resistor R1, and the second pole of the first switching tube Q1 is connected with the first potential end V1.
Specifically, the first and second switching transistors Q1 and Q2 may be bipolar junction transistors (Bipolar Junction Transistor, BJTs). The bias current input terminal Ibs provides bias current for the control electrodes of the first switching tube Q1 and the second switching tube Q2, so that the first switching tube Q1 and the second switching tube Q2 are in a conducting state, and meanwhile, the second electrode current can be regulated through the bias current, so that the second electrode current of the first switching tube Q1 and the second switching tube Q2 is kept unchanged when the temperature is unchanged. In addition, the point where the second resistor R2 is connected to the current adjustment module 121 is respectively the output end of the positive temperature coefficient module 122 and the output end of the current adjustment module 121. At high temperature, when the input voltage vin drops to the undervoltage protection threshold voltage, the switching voltage vdd is relatively large, i.e. the first end potential of the current regulation module 121 is relatively large. Meanwhile, the second pole current of the first switching tube Q1 is increased, so that the first pole current of the first switching tube Q1 is increased, the second end potential of the current adjusting module 121 can be increased, the voltage difference between two ends of the current adjusting module 121 is smaller than or equal to a threshold voltage, a current signal provided by the current adjusting module 121 is reduced, the potential of the output end of the positive temperature coefficient module 122 is smaller than or equal to a conversion threshold voltage, and the signal converting module 123 outputs an under-voltage protection signal according to the potential of the control end. The control unit 130 controls the voltage conversion unit 110 to perform an under-voltage protection operation according to the under-voltage protection signal, so that the voltage conversion unit 110 realizes the under-voltage protection. Therefore, the voltage difference change at two ends of the current regulation module 121 caused by the temperature change can be relieved through the first switching tube Q1, and the stability of the undervoltage protection threshold voltage of the voltage conversion circuit is improved.
With continued reference to fig. 6, the ptc block 122 further includes a fourth resistor R4; the second pole of the first switching tube Q1 is connected to the first potential terminal V1 via a fourth resistor R4.
Specifically, the first potential terminal V1 may be a ground terminal. By connecting the fourth resistor R4 between the second diode of the first switching tube Q1 and the first potential end V1, the potential of the first switching tube Q1 and the second switching tube Q2 can be increased, so as to ensure the normal operation of the first switching tube Q1 and the second switching tube Q2.
On the basis of the technical schemes, the current adjusting module comprises a current mirror; the current mirror comprises a main body branch and a mirror image branch; the main body branch circuit is connected between the power switch tube and the first pole of the first switch tube, and the mirror image branch circuit is connected between the power switch tube and the second resistor; the main body branch circuit is used for forming mirror current according to the conversion voltage and the first pole current of the first switching tube, and the mirror branch circuit is used for mirroring the mirror current.
Specifically, the body branch may form an image current according to a voltage difference between the power switching tube and the first pole of the first switching tube, and reduce the image current when the voltage difference between the power switching tube and the first pole of the first switching tube is less than or equal to a threshold voltage. The mirror image branch circuit can synchronously reduce the current output to the second resistor when the mirror image current is reduced according to the current ratio of the mirror image current of the mirror image main body branch circuit, so that the potential of the output end of the positive temperature coefficient module is reduced. When the input voltage drops to the undervoltage protection threshold voltage, the potential of the output end of the positive temperature coefficient module is smaller than or equal to the conversion threshold voltage and is output to the control end of the signal conversion module, so that the signal conversion module forms an undervoltage protection signal according to the potential of the control end. The current ratio of the main body branch circuit to the mirror image branch circuit may be greater than 1:1, for example, may be 2:1, so as to ensure that when the first pole of the second switching tube is connected with the output end of the current adjusting module through the second resistor, the second pole of the second switching tube is connected with the second pole of the first switching tube through the first resistor, and the branch circuit where the first switching tube is located and the branch circuit where the second switching tube is located are balanced.
Fig. 7 is a schematic diagram of another voltage conversion circuit according to an embodiment of the invention. As shown in fig. 7, the body leg includes a first transistor T1 and the mirror leg includes a second transistor T2; the first pole of the first transistor T1 and the first pole of the second transistor T2 are connected to the power switch 112, the second pole of the first transistor T1, the gate of the first transistor T1 and the gate of the second transistor T2 are connected to the first pole of the first switch Q1, and the second pole of the second transistor T2 is connected to the second resistor R2.
Specifically, the first transistor T1 and the second transistor T2 are connected back-to-back to form a current mirror, so that the second pole of the second transistor T2 can mirror the mirror current flowing through the first transistor T1 according to the current ratio. The first transistor T1 is connected by a diode. When the input voltage vin gradually decreases, that is, the switching voltage vdd provided by the power switching transistor 112 gradually decreases, the potential of the first electrode of the first transistor T1 gradually decreases, that is, the voltage difference between the first electrode and the gate of the first transistor T1 gradually decreases. When the input voltage vin drops to the undervoltage protection threshold voltage, the voltage difference between the first pole and the gate of the first transistor T1 is less than or equal to the threshold voltage of the first transistor T1, and the operating region of the first transistor T1 enters the linear region from the saturation region, so that the second pole current of the first transistor T1 decreases, and the second pole current of the second transistor T2 decreases. At this time, the current flowing through the second switching tube Q2 decreases, so that the potential of the output end of the positive temperature coefficient module 122 is less than or equal to the switching threshold voltage, and the signal switching module 123 outputs an under-voltage protection signal according to the potential of the control end.
Fig. 8 is a schematic diagram of another voltage conversion circuit according to an embodiment of the invention. As shown in fig. 8, the signal conversion module 123 includes a third transistor T3 and a third resistor R3; the gate of the third transistor T3 is connected to the output terminal of the current adjusting module 121 and the output terminal of the positive temperature coefficient module 122, the first pole of the third transistor T3 is connected to the power switch 112, the second pole of the third transistor T3 is connected to the first terminal of the third resistor R3, and is used as the output terminal of the signal converting module 123, and the second terminal of the third resistor R3 is connected to the first potential terminal V1.
Specifically, the third transistor T3 may be a P-type transistor. When the voltage output by the positive temperature coefficient module 122 is greater than the conversion threshold voltage, the third transistor T3 is turned off. The signal output from the output terminal of the signal conversion module 123 is the sum of the voltage drop of the third resistor R3 and the first potential provided by the first potential terminal V1. For example, the first potential terminal V1 may be a ground terminal, and the signal output by the output terminal of the signal conversion module 123 is a voltage drop of the third resistor R3, which is a low level signal with respect to the converted voltage vdd, that is, the signal output by the output terminal of the signal conversion module 123 is a low level signal, and the control unit 130 does not act according to the low level signal. The third transistor T3 is turned on when the voltage output from the ptc block 122 is less than or equal to the switching threshold voltage. The switching voltage vdd is transmitted to the second pole of the third transistor T3 through the third transistor T3, is high, and is output as an under-voltage protection signal. The control unit 130 controls the voltage conversion unit 110 to perform the under-voltage protection according to the under-voltage protection signal. The switching threshold voltage may be a sum of a voltage drop across the third resistor R3, the first potential, and a threshold voltage of the third transistor T3.
Fig. 9 is a schematic diagram of another voltage conversion circuit according to an embodiment of the invention. As shown in fig. 9, the under-voltage protection unit 120 further includes a bias current generating module 124; a first input end of the bias current generating module 124 is connected with the power switch tube 112, a second input end of the bias current generating module 124 is connected with the first potential end V1, and an output end of the bias current generating module 124 is used as a bias current input end Ibs; the bias current generating module 124 is configured to form a bias current according to the switching voltage vdd and the first potential provided by the first potential terminal V1.
Specifically, the bias current generating module 124 may form a bias current according to the switching voltage vdd output by the power switch tube 112 and the first potential provided by the first potential end V1, and output the bias current to the control electrodes of the first switch tube Q1 and the second switch tube Q2, so as to provide the bias current for the first switch tube Q1 and the second switch tube Q2, so that the first switch tube Q1 and the second switch tube Q2 are in a path state, and meanwhile, the bias current may be adjusted according to the change of the current signal, so as to ensure that the second currents of the first switch tube Q1 and the second switch tube Q2 are unchanged.
With continued reference to fig. 9, the bias current generation module 124 includes a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6; the first end of the fourth resistor R4 is connected to the power switch 112, the second end of the fourth resistor R4 is connected to the first end of the fifth resistor R5 and the first end of the sixth resistor R6, the second end of the fifth resistor R5 is connected to the first potential end V1, and the second end of the sixth resistor R6 is used as the output end of the bias current generating module 124.
Specifically, the fourth resistor R4 and the fifth resistor R5 are connected between the power switch tube 112 and the first potential end V1, and divide the potentials at the two ends of the power switch tube 112 and the first potential end V1 and output the divided potentials to the sixth resistor R6 to regulate the current on the sixth resistor R6, so that bias currents can be formed and output to the control electrodes of the first switch tube Q1 and the second switch tube Q2.
Fig. 10 is a schematic diagram of another voltage conversion circuit according to an embodiment of the invention. As shown in fig. 10, the input module 111 includes a voltage dividing submodule 1111 and a voltage stabilizing submodule 1112; an input end of the voltage division submodule 1111 is used for accessing an input voltage vin, an output end of the voltage division submodule 1111 is connected with the voltage stabilizing submodule 1112, the voltage division submodule 1111 is used for converting the input voltage vin into a first voltage, and the voltage stabilizing submodule 1112 is used for stabilizing the first voltage; the control pole of the power switch tube 112 is connected with the voltage stabilizing submodule 1112, the first pole of the power switch tube 112 is connected with the power input end VDD2, and the second pole of the power switch tube 112 is used as the output end of the voltage conversion unit 110; the power switch 112 is configured to output a switching voltage vdd according to the first voltage.
Specifically, the voltage dividing submodule 1111 has a voltage dividing function. Fig. 10 shows an exemplary voltage dividing submodule 1111 including a voltage dividing resistor R5 and a first voltage stabilizing capacitor Ct1, wherein a first end of the voltage dividing resistor R5 is used for receiving an input voltage vin, a second end of the voltage dividing resistor R5 is connected to a first pole of the first voltage stabilizing capacitor Ct1, and is used as an output end of the voltage dividing submodule 1111, and a second pole of the first voltage stabilizing capacitor Ct1 is connected to a first potential end V1. After dividing the input voltage vin by the dividing resistor R5, the dividing sub-module 1111 outputs the first voltage. The voltage stabilizing sub-module 1112 may include a first voltage stabilizing tube D1, where a cathode of the first voltage stabilizing tube D1 is connected to an output terminal of the voltage dividing sub-module 1111, and an anode of the first voltage stabilizing tube D1 is connected to the first potential terminal V1. After the voltage dividing submodule 1111 outputs the first voltage, the first voltage stabilizing tube D1 stabilizes the first voltage and outputs the first voltage to the control electrode of the power switching tube 112, so as to control the state of the power switching tube 112. When the power switch 112 is turned on, the second pole of the power switch 112 outputs a voltage of a difference between the first voltage and the threshold voltage of the power switch 112 as the switching voltage vdd. For example, when the input voltage vin is 12V, the first voltage may be 5.8V, the threshold voltage of the power switch 112 may be 1.3V, and the switching voltage vdd is 5.8V-1.3 v=4.5V.
With continued reference to fig. 10, the voltage conversion unit further includes a second voltage stabilizing tube D2, where an anode of the second voltage stabilizing tube D2 is connected to the first potential end V1, and a cathode of the second voltage stabilizing tube D2 is connected to the second pole of the power switch tube 112, and is configured to stabilize the converted voltage vdd output by the second pole of the power switch tube 112.
On the basis of the technical schemes, the input module further comprises a filtering module, the filtering module is connected between the voltage dividing submodule and the power switch tube, and the filtering module is used for filtering the first voltage.
Specifically, the filtering module may include a filtering resistor and a filtering capacitor, where a first end of the filtering resistor is connected to an output end of the voltage dividing sub-module, a second end of the filtering resistor and a second pole of the filtering capacitor are connected to a control pole of the power switch tube, and a first pole of the filtering capacitor is connected to the first potential end. The filter resistor and the filter capacitor form a resistance-capacitance filter circuit for filtering the first voltage.
The embodiment of the invention also provides a voltage conversion chip. The voltage conversion chip comprises the voltage conversion circuit provided by any embodiment of the invention. The voltage conversion chip comprises the voltage conversion circuit provided by any embodiment of the invention, so that the voltage conversion chip has the same beneficial effects as the voltage conversion circuit and is not repeated here.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (8)
1. The voltage conversion circuit is characterized by comprising a voltage conversion unit, an undervoltage protection unit and a control unit;
the voltage conversion unit comprises an input module and a power switch tube, wherein the input module is used for converting input voltage into first voltage; the power switch tube is connected with the input module and is used for outputting a conversion voltage according to the first voltage;
the under-voltage protection unit comprises a current regulation module, a positive temperature coefficient module and a signal conversion module; the first end of the current regulating module and the first end of the signal conversion module are connected with the power switch tube, the second end of the current regulating module is connected with the first end of the positive temperature coefficient module, the output end of the current regulating module and the output end of the positive temperature coefficient module are connected with the control end of the signal conversion module, and the second end of the positive temperature coefficient module is connected with the first potential end; the current regulation module is used for regulating a current signal flowing through the positive temperature coefficient module according to the conversion voltage, the positive temperature coefficient module is used for regulating the control end potential of the signal conversion module according to the current signal and the temperature, and the signal conversion module is used for outputting an under-voltage protection signal when the control end potential is smaller than or equal to the conversion threshold voltage;
The control unit is connected with the signal conversion module and is used for controlling the voltage conversion unit to perform under-voltage protection action according to the under-voltage protection signal;
the positive temperature coefficient module comprises a first switching tube, a second switching tube, a first resistor and a second resistor;
the control poles of the first switching tube and the second switching tube are connected with a bias current input end, the first pole of the first switching tube is connected with the second end of the current regulating module, the first pole of the second switching tube is connected with the output end of the current regulating module through the second resistor, the second pole of the second switching tube is connected with the second pole of the first switching tube through the first resistor, and the second pole of the first switching tube is connected with the first potential end;
the input module comprises a voltage division sub-module and a voltage stabilizing sub-module;
the input end of the voltage division submodule is used for being connected with the input voltage, the output end of the voltage division submodule is connected with the voltage stabilizing submodule, the voltage division submodule is used for converting the input voltage into the first voltage, and the voltage stabilizing submodule is used for stabilizing the first voltage; the control pole of the power switch tube is connected with the voltage stabilizing submodule, the first pole of the power switch tube is connected with the power input end, and the second pole of the power switch tube is used as the output end of the voltage conversion unit; the power switch tube is used for outputting the conversion voltage according to the first voltage;
The voltage dividing submodule comprises a voltage dividing resistor and a first voltage stabilizing capacitor; the first end of the voltage dividing resistor is used as an input end of the voltage dividing submodule, the second end of the voltage dividing resistor is connected with the first pole of the first voltage stabilizing capacitor and is used as an output end of the voltage dividing submodule, and the second pole of the first voltage stabilizing capacitor is connected with the first potential end;
the voltage stabilizing submodule comprises a first voltage stabilizing tube; the cathode of the first voltage stabilizing tube is connected with the output end of the voltage dividing submodule and the control electrode of the power switch tube, and the anode of the first voltage stabilizing tube is connected with the first potential end.
2. The voltage conversion circuit of claim 1, wherein the current regulation module comprises a current mirror; the current mirror comprises a main body branch and a mirror image branch; the main body branch is connected between the power switch tube and a first pole of the first switch tube, and the mirror image branch is connected between the power switch tube and the second resistor; the main body branch circuit is used for forming mirror current according to the conversion voltage and the first pole current of the first switching tube, and the mirror branch circuit is used for mirroring the mirror current.
3. The voltage conversion circuit of claim 2, wherein the body leg comprises a first transistor and the mirror leg comprises a second transistor;
the first pole of the first transistor and the first pole of the second transistor are connected with the power switch, the second pole of the first transistor, the grid of the first transistor and the grid of the second transistor are connected with the first pole of the first switch, and the second pole of the second transistor is connected with the second resistor.
4. A voltage conversion circuit according to any one of claims 1-3, wherein the signal conversion module comprises a third transistor and a third resistor;
the grid electrode of the third transistor is connected with the output end of the current regulating module and the output end of the positive temperature coefficient module, the first electrode of the third transistor is connected with the power switch transistor, the second electrode of the third transistor is connected with the first end of the third resistor and serves as the output end of the signal converting module, and the second end of the third resistor is connected with the first potential end.
5. The voltage conversion circuit of claim 1, wherein the positive temperature coefficient module further comprises a fourth resistor; the second pole of the first switching tube is connected with the first potential end through the fourth resistor.
6. The voltage conversion circuit of claim 1, wherein the under-voltage protection unit further comprises a bias current generation module;
the first input end of the bias current generating module is connected with the power switch tube, the second input end of the bias current generating module is connected with the first potential end, and the output end of the bias current generating module is used as the bias current input end; the bias current generation module is used for forming bias current according to the conversion voltage and the first potential provided by the first potential end.
7. The voltage conversion circuit of claim 6, wherein the bias current generation module comprises a fourth resistor, a fifth resistor, and a sixth resistor;
the first end of the fourth resistor is connected with the power switch tube, the second end of the fourth resistor is connected with the first end of the fifth resistor and the first end of the sixth resistor, the second end of the fifth resistor is connected with the first potential end, and the second end of the sixth resistor is used as an output end of the bias current generation module.
8. A voltage conversion chip comprising the voltage conversion circuit of any one of claims 1-7.
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| CN101093956A (en) * | 2007-07-20 | 2007-12-26 | 开源集成电路(苏州)有限公司 | Under voltage locking circuit with temperature compensation |
| CN101237182A (en) * | 2008-02-19 | 2008-08-06 | 北京中星微电子有限公司 | A method for forming the standard voltage of under-voltage lock circuit and its circuit |
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| CN205070828U (en) * | 2015-10-23 | 2016-03-02 | 深圳市稳先微电子有限公司 | AC -DC single -stage control chip and control system thereof |
| CN107425717A (en) * | 2017-06-02 | 2017-12-01 | 江苏万邦微电子有限公司 | A kind of power management switch converters for realizing true turn-off function |
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| TW200713733A (en) * | 2005-09-14 | 2007-04-01 | Richtek Techohnology Corp | Protecting device and method for protecting power supply system |
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| CN101093956A (en) * | 2007-07-20 | 2007-12-26 | 开源集成电路(苏州)有限公司 | Under voltage locking circuit with temperature compensation |
| CN101237182A (en) * | 2008-02-19 | 2008-08-06 | 北京中星微电子有限公司 | A method for forming the standard voltage of under-voltage lock circuit and its circuit |
| JP2013074737A (en) * | 2011-09-28 | 2013-04-22 | Shindengen Electric Mfg Co Ltd | Electric power conversion device and overvoltage protection method of the electric power conversion device |
| CN205070828U (en) * | 2015-10-23 | 2016-03-02 | 深圳市稳先微电子有限公司 | AC -DC single -stage control chip and control system thereof |
| CN107425717A (en) * | 2017-06-02 | 2017-12-01 | 江苏万邦微电子有限公司 | A kind of power management switch converters for realizing true turn-off function |
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