CN117388561B - Current detection circuit with wide voltage range and switching power supply - Google Patents

Current detection circuit with wide voltage range and switching power supply Download PDF

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Publication number
CN117388561B
CN117388561B CN202311670096.8A CN202311670096A CN117388561B CN 117388561 B CN117388561 B CN 117388561B CN 202311670096 A CN202311670096 A CN 202311670096A CN 117388561 B CN117388561 B CN 117388561B
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current
tube
nmos tube
electrically connected
nmos
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CN117388561A (en
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罗寅
谭在超
丁国华
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Suzhou Covette Semiconductor Co ltd
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Suzhou Covette Semiconductor Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current 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

Abstract

The invention relates to the technical field of current detection and discloses a current detection circuit and a switching power supply with wide voltage range, wherein the current detection circuit comprises a sampling resistor, a first load resistor, a second load resistor, an output resistor, a low-voltage detection unit, a high-voltage detection unit and a control switch; in actual use, the invention can know the relation between the voltage drop on the output voltage and the current flowing through the sampling resistor by arranging the high-voltage detection unit and the low-voltage detection unit and analyzing the other end of the first load resistor and the other end of the second load resistor according to the kirchhoff current rule by enabling the high-voltage detection unit and the low-voltage detection unit to generate corresponding currents based on the input common-mode voltage, thereby realizing the current detection of a large range of voltage without worrying about the influence of the input common-mode voltage on the current detection precision.

Description

Current detection circuit with wide voltage range and switching power supply
Technical Field
The invention relates to the technical field of current detection, in particular to a current detection circuit with a wide voltage range and a switching power supply.
Background
In a switching power supply system, it is necessary to detect a current in a circuit using a current detection circuit and feed back the detection result to a control circuit to realize dynamic adjustment.
The current detection method is that a sampling resistor with a smaller resistance value is introduced into a to-be-detected passage, the voltage values at two ends of the resistor are detected, and the current value of the passage can be obtained through conversion. The current detection circuit is divided into a low-voltage side and a high-voltage side, and as shown in FIG. 1, the current sampling circuit for detecting the low-voltage side comprises a sampling resistor R SENSE Placed between load and ground, the operational amplifier will sample the resistance R SENSE The voltage is directly sampled and amplified in phase to be output, namely。
As shown in fig. 2, the current detection circuit for detecting the high voltage side is a sampling resistor R SENSE The operational amplifier is arranged between the positive power supply VCC and the load, and acts as a transconductance amplifier to sample the resistor R SENSE Is sampled and converted into a current, which is finally converted into a voltage at a resistor R3, i.e. there is。
With the circuits of fig. 1 and 2, the conventional operational amplifier has limitations on the common-mode voltage range of the input signal due to the use of the pair-pipe input, and affects the performance and even the function of the input signal when the common-mode voltage of the input signal is too high or too low. However, in an application scenario where current detection is required, the detected voltage is high or low, possibly exceeding the voltage of the power supply VCC, or possibly being lower than the ground potential, and even when the current detection circuit works normally, the conventional current detection circuit cannot work normally once the detected voltage exceeds the input common-mode voltage range of the operational amplifier.
Disclosure of Invention
In view of the shortcomings of the background technology, the invention provides a current detection circuit with a wide voltage range and a switching power supply, and aims to solve the technical problem that the current detection circuit cannot normally detect current when the detected voltage exceeds the input common-mode voltage of an operational amplifier.
In order to solve the technical problems, in a first aspect, the present invention provides the following technical solutions: a current detection circuit with a wide voltage range comprises a sampling resistor, a first load resistor, a second load resistor, an output resistor, a low-voltage detection unit, a high-voltage detection unit and a control switch;
one end of the sampling resistor is electrically connected with one end of the first load resistor and is used for inputting current to be detected, the other end of the first load resistor is electrically connected with the low-voltage detection unit and the high-voltage detection unit respectively, the other end of the sampling resistor is electrically connected with one end of the second load resistor, and the other end of the second load resistor is electrically connected with the low-voltage detection unit and the high-voltage detection unit;
the low voltage detection unit is used for generating a current I flowing to the other end of the first load resistor P1 Generating a current I flowing to the other end of the second load resistor P2 And current I P3 Generating a current I flowing to one end of the output resistor P4 The other end of the output resistor is grounded, and the output current I is stopped when the voltage at the other end of the sampling resistor is higher than the first threshold voltage P1 Current I P2 Current I P3 And current I P4 ；
The high voltage detection unit is used for generating a current I flowing from the other end of the first load resistor N1 And generating a current I flowing from the other end of the second load resistor N2 Stopping generating the current I when the voltage at one end of the sampling resistor is lower than the second threshold voltage N1 And current I N2 ；
The input end of the control switch is electrically connected with the first load resistor, the output end of the control switch is electrically connected with one end of the output resistor, the control end of the control switch is electrically connected with the high-voltage detection unit, and the high-voltage detection unit generates current I N1 And current I N2 When a current I is input to one end of the output resistor M17 。
In a certain implementation manner of the first aspect, the low voltage detection unit includes a PMOS transistor M1, a PMOS transistor M2, an NMOS transistor M3, an NMOS transistor M4, an NMOS transistor M5, an NMOS transistor M6, a current mirror, an NMOS transistor M15, and an NMOS transistor M16;
the source electrode of the PMOS tube M1 is electrically connected with the source electrode of the PMOS tube M2 and is used for being connected with a power supply VCC; the grid electrode of the PMOS tube M1 is electrically connected with the grid electrode of the PMOS tube M2 for accessing the control voltage V BP The method comprises the steps of carrying out a first treatment on the surface of the The drain electrode of the PMOS tube M1 is respectively and electrically connected with the drain electrode of the NMOS tube M3 and the grid electrode of the NMOS tube M15, the drain electrode of the PMOS tube M2 is respectively and electrically connected with the drain electrode of the NMOS tube M4, the grid electrode of the NMOS tube M3 and the grid electrode of the NMOS tube M4, the drain electrode of the NMOS tube M15 is electrically connected with the main branch of the current mirror, the secondary branch of the current mirror is electrically connected with one end of the output resistor, and the current IP4 is output;
the source electrode of the NMOS tube M3 is electrically connected with the drain electrode of the NMOS tube M5, the source electrode of the NMOS tube M4 is electrically connected with the drain electrode of the NMOS tube M6, and the source electrode of the NMOS tube M15 is electrically connected with the drain electrode of the NMOS tube M16;
the grid electrode of the NMOS tube M5, the grid electrode of the NMOS tube M6 and the grid electrode of the NMOS tube M16 are electrically connected for accessing the control voltage V BN2 ；
The source electrode of the NMOS tube M5 is used for outputting current I P1 The source electrode of the NMOS tube M6 is used for outputting current I P2 The source electrode of the NMOS tube M16 outputs a current I P3 。
In certain embodiments of the first aspect, the current I P1 And current I P2 Is the same size.
In a certain implementation manner of the first aspect, the size of the PMOS transistor M1 is the same as the size of the PMOS transistor P2, the size of the NMOS transistor P3 is the same as the size of the NMOS transistor P4, and the sizes of the NMOS transistor M5 and the NMOS transistor M6 are the same.
In a certain implementation manner of the first aspect, the current mirror includes a PMOS transistor M13 and a PMOS transistor M14; the source electrode of the PMOS tube M13 is electrically connected with the source electrode of the PMOS tube M14 for accessing the power supply VCC, the grid electrode of the PMOS tube M13 is respectively electrically connected with the drain electrode of the PMOS tube M13, the drain electrode of the NMOS tube M15 and the grid electrode of the NMOS tube M14, and the drain electrode of the PMOS tube M14 outputs a current I P4 。
In a certain implementation manner of the first aspect, the high voltage detection unit includes a PMOS transistor M7, a PMOS transistor M8, an NMOS transistor M9, an NMOS transistor M10, an NMOS transistor M11, and an NMOS transistor M12;
the source electrode of the PMOS tube M7 is electrically connected with the other end of the first load resistor, the grid electrode of the PMOS tube M7 is electrically connected with the grid electrode of the PMOS tube M8, the drain electrode of the PMOS tube M7 and the drain electrode of the NMOS tube M9 respectively, the source electrode of the PMOS tube M8 is electrically connected with the other end of the second load resistor, and the drain electrode of the PMOS tube M8 is electrically connected with the drain electrode of the NMOS tube M10 and the control end of the control switch respectively;
the grid electrode of the NMOS tube M9 is electrically connected with the grid electrode of the NMOS tube M10 for accessing the control voltage V BN1 The source of the NMOS tube M9 is electrically connected with the drain of the NMOS tube M11, and the drain of the source NMOS tube M12 of the NMOS tube M10The grid electrode of the NMOS tube M11 is electrically connected with the grid electrode of the NMOS tube M12 for inputting a control voltage V BN0 The source electrode of the NMOS tube M11 and the source electrode of the NMOS tube M12 are grounded;
the current I N1 The current I is grounded through the PMOS tube M7, the NMOS tube M9 and the NMOS tube M11 N2 Through PMOS tube M8, NMOS tube M10 and NMOS tube M12, the ground connection.
In certain embodiments of the first aspect, the current I N1 And current I N2 Is the same size.
In a certain implementation manner of the first aspect, the PMOS transistor M7 and the PMOS transistor M8 have the same size, the NMOS transistor M9 and the NMOS transistor M10 have the same size, and the NMOS transistor M11 and the NMOS transistor M12 have the same size.
In a certain implementation manner of the first aspect, the control switch is a PMOS transistor M17, a source of the PMOS transistor M17 is an input end of the control switch, a gate of the PMOS transistor M17 is a control end of the control switch, and a drain of the PMOS transistor M17 is an output end of the control switch.
In a second aspect, the present invention provides a switching power supply comprising a wide voltage range current detection circuit as described above.
Compared with the prior art, the invention has the following beneficial effects: according to the invention, the high-voltage detection unit and the low-voltage detection unit are arranged, and the corresponding currents are generated by the high-voltage detection unit and the low-voltage detection unit based on the magnitude of the input common-mode voltage, and the relation between the voltage drop of the output voltage and the current flowing through the sampling resistor can be known by analyzing the other end of the first load resistor and the other end of the second load resistor according to the kirchhoff current law, so that the current detection of a large range of voltage can be realized, and the influence of the input common-mode voltage on the current detection precision is not worried.
Drawings
FIG. 1 is a schematic diagram of a prior art low side current sense;
FIG. 2 is a schematic diagram of a prior art high side current sense;
FIG. 3 is a schematic view of the structure of the present invention in an embodiment;
fig. 4 is a circuit diagram of one implementation of the present invention in an embodiment.
Detailed Description
The invention will now be described in further detail with reference to the accompanying drawings. The drawings are simplified schematic representations which merely illustrate the basic structure of the invention and therefore show only the structures which are relevant to the invention.
With the existing current detection circuit, since the operational amplifier adopted can accurately detect only when the adaptive common-mode voltage is input, the current detection of a wide range of voltage cannot be performed, for example, when the operational amplifier detects the current exceeding the power supply VCC voltage or the voltage lower than the ground potential, the current detection cannot be performed normally.
In order to achieve current detection of a wide range of input voltages, as shown in FIG. 3, the present embodiment provides a wide voltage range current detection circuit comprising a sampling resistor R SENSE First load resistor R 1 Second load resistor R 2 Output resistor R 3 A low voltage detection unit 1, a high voltage detection unit 2 and a control switch 3;
sampling resistor R SENSE One end is connected with a first load resistor R 1 One end is electrically connected for inputting current to be measured, and a first load resistor R 1 The other end is respectively and electrically connected with the low-voltage detection unit 1 and the high-voltage detection unit 2, and the sampling resistor R SENSE The other end is connected with a second load resistor R 2 One end is electrically connected with a second load resistor R 2 The other end is electrically connected with the low-voltage detection unit 1 and the high-voltage detection unit 2;
the low voltage detection unit 1 is used for generating a current flowing to a first load resistor R 1 Current I at the other end P1 Generating a flow to a second load resistor R 2 Current I at the other end P2 And current I P3 Generating a flow direction output resistor R 3 Current I at one end P4 Output resistor R 3 The other end is grounded and is connected with the sampling resistor R SENSE Stopping outputting the current I when the voltage at the other end is higher than the first threshold voltage P1 Current I P2 Current I P3 And currentI P4 ；
The high voltage detection unit 2 is used for generating a slave first load resistor R 1 Current I flowing from the other end N1 And generating a slave second load resistor R 2 Current I flowing from the other end N2 At the sampling resistor R SENSE Stopping generating current I when the voltage at one end is lower than the second threshold voltage N1 And current I N2 ；
The input end of the control switch 3 and the first load resistor R 1 The output end of the control switch 3 is electrically connected with one end of the output resistor R3, the control end of the control switch 3 is electrically connected with the high voltage detection unit 2, and the high voltage detection unit 2 generates current I N1 And current I N2 Time-oriented output resistor R 3 One end inputs current I M17 。
In actual use, the output resistor R 3 The voltage at the voltage is the output voltage of the invention, which reflects the flow through the sampling resistor R SENSE Is a current magnitude of (a); the current detection circuit in the present embodiment samples the resistor R through the low voltage detection unit 1 and the high voltage detection unit 2 SENSE Judging the voltage at one end and according to the sampling resistor R SENSE The voltage at one end generates a current I P1 Current I P2 Current I P3 And current I P4 Or generate a current I N1 And current I N2 Or simultaneously generate current I P1 Current I P2 Current I P3 Current I P4 Current I N1 And current I N2 The first load resistor R is controlled by the kirchhoff current law 1 Another end and a second load resistor R 2 The other end is analyzed to know the output resistance R 3 Voltage across and flow through a first load resistor R 1 Current flowing through the second load resistor R 2 Current of (1), current I P1 Current I P2 Current I P3 Current I P4 Current I N1 And current I N2 So that current checking can be performed when a wide range of common mode voltages is input.
As shown in fig. 4, the low voltage detection unit 1 includes a PMOS transistor M1, a PMOS transistor M2, an NMOS transistor M3, an NMOS transistor M4, an NMOS transistor M5, an NMOS transistor M6, a current mirror 10, an NMOS transistor M15, and an NMOS transistor M16;
the source electrode of the PMOS tube M1 is electrically connected with the source electrode of the PMOS tube M2 and is used for being connected with a power supply VCC; the grid electrode of the PMOS tube M1 is electrically connected with the grid electrode of the PMOS tube M2 and is used for accessing the control voltage V BP The method comprises the steps of carrying out a first treatment on the surface of the The drain electrode of the PMOS tube M1 is respectively and electrically connected with the drain electrode of the NMOS tube M3 and the grid electrode of the NMOS tube M15, the drain electrode of the PMOS tube M2 is respectively and electrically connected with the drain electrode of the NMOS tube M4, the grid electrode of the NMOS tube M3 and the grid electrode of the NMOS tube M4, the drain electrode of the NMOS tube M15 is electrically connected with the main branch of the current mirror 10, the secondary branch of the current mirror 10 is electrically connected with one end of the output resistor, and the output current I P4 ；
The source electrode of the NMOS tube M3 is electrically connected with the drain electrode of the NMOS tube M5, the source electrode of the NMOS tube M4 is electrically connected with the drain electrode of the NMOS tube M6, and the source electrode of the NMOS tube M15 is electrically connected with the drain electrode of the NMOS tube M16;
the grid electrode of the NMOS tube M5, the grid electrode of the NMOS tube M6 and the grid electrode of the NMOS tube M16 are electrically connected and used for accessing the control voltage V BN2 ；
The source electrode of the NMOS tube M5 is used for outputting current I P1 The source of NMOS tube M6 is used for outputting current I P2 Source electrode of NMOS tube M16 outputs current I P3 。
In this embodiment, for ease of calculation, the current I P1 And current I P2 Is the same size.
To let current I P1 And current I P2 In this embodiment, the size of the PMOS transistor M1 and the size of the PMOS transistor P2 in fig. 4 are the same, the size of the NMOS transistor P3 and the size of the NMOS transistor P4 are the same, and the sizes of the NMOS transistor M5 and the NMOS transistor M6 are the same.
In addition, to ensure the current I P1 And current I P2 The NMOS tube P3 and the NMOS tube P4 are connected to form a current mirror structure.
In some embodiments, the current I can be changed according to actual requirements P1 And current I P2 For example, the magnitude of the current I can be P1 And current I P2 Is a multiple relationship.
In the drawings4, the current mirror 10 includes a PMOS transistor M13 and a PMOS transistor M14, wherein the PMOS transistor M13 is a master branch, and the PMOS transistor M14 is a slave branch; the source electrode of the PMOS tube M13 is electrically connected with the source electrode of the PMOS tube M14 for accessing the power supply VCC, the grid electrode of the PMOS tube M13 is respectively electrically connected with the drain electrode of the PMOS tube M13, the drain electrode of the NMOS tube M15 and the grid electrode of the NMOS tube M14, and the drain electrode of the PMOS tube M14 outputs the current I P4 。
In this embodiment, the current flowing from the PMOS transistor M13 is the current I P3 For ease of calculation, in this embodiment, the current I P3 And current I P4 The current mirror ratio of the current mirror 10 is 1, and in order to make the current mirror ratio of the current mirror 10 1, the PMOS transistor M13 and the PMOS transistor M14 in fig. 4 have the same size.
In fig. 4, the NMOS transistor M5, the NMOS transistor M6, and the NMOS transistor M16 are used as control switches, and the on/off of the NMOS transistor M5, the NMOS transistor M6, and the NMOS transistor M16 is controlled to control whether the low voltage detection unit 1 generates the current I P1 Current I P2 Current I P3 Current I P4 。
In fig. 4, the high voltage detection unit 2 includes a PMOS transistor M7, a PMOS transistor M8, an NMOS transistor M9, an NMOS transistor M10, an NMOS transistor M11, and an NMOS transistor M12;
source electrode of PMOS tube M7 and first load resistor R 1 The other end is electrically connected with the grid electrode of the PMOS tube M7, the grid electrode of the PMOS tube M8, the drain electrode of the PMOS tube M7 and the drain electrode of the NMOS tube M9, and the source electrode of the PMOS tube M8 and the second load resistor R 2 The other end is electrically connected with the drain electrode of the PMOS tube M8 and the drain electrode of the NMOS tube M10 and the control end of the control switch 3 respectively;
the grid electrode of the NMOS tube M9 is electrically connected with the grid electrode of the NMOS tube M10 for accessing the control voltage V BN1 The source of the NMOS tube M9 is electrically connected with the drain of the NMOS tube M11, the drain of the source NMOS tube M12 of the NMOS tube M10 is electrically connected, the grid of the NMOS tube M11 is electrically connected with the grid of the NMOS tube M12 for inputting the control voltage V BN0 The source electrode of the NMOS tube M11 and the source electrode of the NMOS tube M12 are grounded;
current I N1 Through the PMOS tube M7, the NMOS tube M9 and the NMOS tube M11, the current I is grounded N2 Through PMOS tube M8, NMOS tube M10 and NMOS tube M12, the ground connection.
Also, in the present embodiment, for the convenience of calculation, the current I N1 And current I N2 Is the same size.
To let current I N1 And current I N2 In this embodiment, the PMOS transistor M7 and the PMOS transistor M8 in fig. 4 have the same size, the NMOS transistor M9 and the NMOS transistor M10 have the same size, and the NMOS transistor M11 and the NMOS transistor M12 have the same size.
Likewise, to further ensure the current I N1 And current I N2 The PMOS tube M7 and the PMOS tube M8 are also connected into a current mirror structure.
In some embodiments, the current I can be changed according to actual requirements N1 And current I N2 For example, the magnitude of the current I can be N1 And current I N2 Is a multiple relationship.
In this embodiment, in fig. 4, the control switch 3 is a PMOS transistor M17, the source of the PMOS transistor M17 is the input end of the control switch 3, the gate of the PMOS transistor M17 is the control end of the control switch 3, and the drain of the PMOS transistor M17 is the output end of the control switch 3.
In addition, for the high voltage detection unit 2 in fig. 4, the PMOS transistor M7 and the PMOS transistor M8 are used as control switches, and whether the high voltage detection unit 2 generates the current I can be controlled by controlling the on/off of the PMOS transistor M7 and the PMOS transistor M8 N1 And current I N2 。
The circuit of fig. 4 was analyzed as follows: when sampling resistor R SENSE The voltage at, i.e. common mode voltageThe size of the PMOS transistor M7, the PMOS transistor M8 and the PMOS transistor M17 is reduced>In this case, the NMOS transistor M9, the NMOS transistor M10, the NMOS transistor M11 and the NMOS transistor M12 are pressed into the linear region, so that the above-mentioned +.>And->Equal, there is->The PMOS tube M7, the PMOS tube M8 and the PMOS tube M17 are all in a cut-off region, at the moment, the high-voltage detection unit 2 does not work, and the low-voltage detection unit 1 can work normally; wherein->The threshold voltages of the PMOS tube M7, the PMOS tube M8 and the PMOS tube M17 are the same when the sizes of the PMOS tube M7, the PMOS tube M8 and the PMOS tube M17 are the same, and the threshold voltages of the PMOS tube M7, the PMOS tube M8 and the PMOS tube M17 are the same.
When the common-mode voltage isRising to make NMOS tube M5, NMOS tube M6 and NMOS tube M16Namely there is->In this case, the NMOS transistor M5, the NMOS transistor M6, and the NMOS transistor M16 are all in the cut-off region, and the low voltage detection unit 1 does not operate and the high voltage detection unit 2 can operate normally.
When (when)At this time, the high-voltage detection unit 2 and the low-voltage detection unit 1 operate simultaneously.
When the high voltage detection unit 2 is operated and the low voltage detection unit 1 is not operated, the bypass current in the circuit is due toAnd the VGS voltages of the PMOS tube M7 and the PMOS tube M8 are equal, namely the voltages of the point C and the point D are equal.
Wherein the point C voltage:。
d electric voltage:。
then, there are:。
namely:。
due toAnd->,
The method can obtain:。
therefore:。
when the low voltage detection unit 1 is operated and the high voltage detection unit 2 is not operated, the common mode voltage is usedThe NMOS tube M5, the NMOS tube M6 and the NMOS tube M16 are operated in a linear region and are equivalent to a low-resistance switch, and the branch current in the circuit is +.>The VGS voltages of the NMOS transistor M3 and the NMOS transistor M4 are equal, i.e., the voltages at the points C and D are equal.
Wherein the point C voltage:。
d electric voltage:。
then, there are:。
namely:。
due toAnd->,
The method can obtain:。
and M13 and M14 form a current mirror, so。
Then:。
when both the high voltage detection unit 2 and the low voltage detection unit 1 are operated, there are, for nodes C and D:
point C voltage:。
d electric voltage:。
and is also provided with。
I.e.。
Then there is
Due to，/>=/>，/>，
Therefore, it is。
Then。
With the analysis, the current detection circuit of the invention can realize a wide input common-mode voltageThe current detection of the voltage sensor can adaptively adjust the working mode according to the voltages with different magnitudes, and the applicability is wide; in addition, by adjusting the sampling resistor R SENSE First load resistor R 1 Second load resistor R 2 And an output resistor R 3 The current detection amplification factor can be adjusted, so that different post-stage circuits can be adapted.
In a second aspect, the present invention provides a switching power supply comprising a wide voltage range current detection circuit as described above.
The present invention has been made in view of the above-described circumstances, and it is an object of the present invention to provide a portable electronic device capable of performing various changes and modifications without departing from the scope of the technical spirit of the present invention. The technical scope of the present invention is not limited to the description, but must be determined according to the scope of claims.

Claims (9)

1. The current detection circuit with the wide voltage range is characterized by comprising a sampling resistor, a first load resistor, a second load resistor, an output resistor, a low-voltage detection unit, a high-voltage detection unit and a control switch;
one end of the sampling resistor is electrically connected with one end of the first load resistor and is used for inputting current to be detected, the other end of the first load resistor is electrically connected with the low-voltage detection unit and the high-voltage detection unit respectively, the other end of the sampling resistor is electrically connected with one end of the second load resistor, and the other end of the second load resistor is electrically connected with the low-voltage detection unit and the high-voltage detection unit;
the low voltage detection unit is used for generating a current IP flowing to the other end of the first load resistor 1 Generating a current IP flowing to the other end of the second load resistor 2 And current IP 3 Generating a current IP flowing to one end of the output resistor 4 And stopping outputting the current IP when the voltage at the other end of the sampling resistor is higher than the first threshold voltage 1 Current IP 2 Current IP 3 And current IP 4 The method comprises the steps of carrying out a first treatment on the surface of the The other end of the output resistor is grounded;
the high voltage detection unit is used for generating a current IN flowing from the other end of the first load resistor 1 And generating a current IN flowing from the other end of the second load resistor 2 Stopping generating the current IN when the voltage at one end of the sampling resistor is lower than the second threshold voltage 1 And current IN 2 ；
The input end of the control switch is electrically connected with the first load resistor, the output end of the control switch is electrically connected with one end of the output resistor, the control end of the control switch is electrically connected with the high-voltage detection unit, and the high-voltage detection unit generates current IN 1 And current IN 2 When current IM1 is input to one end of the output resistor 7
The low-voltage detection unit comprises a PMOS tube M1, a PMOS tube M2, an NMOS tube M3, an NMOS tube M4, an NMOS tube M5, an NMOS tube M6, a current mirror, an NMOS tube M15 and an NMOS tube M16;
the source electrode of the PMOS tube M1 is electrically connected with the source electrode of the PMOS tube M2 and is used for being connected with a power supply VCC; the grid electrode of the PMOS tube M1 is electrically connected with the grid electrode of the PMOS tube M2 for accessing the control voltage V BP The method comprises the steps of carrying out a first treatment on the surface of the The drain electrode of the PMOS tube M1 is respectively connected with the drain electrode of the NMOS tube M3The drain electrode of the PMOS tube M2 is electrically connected with the drain electrode of the NMOS tube M4, the gate electrode of the NMOS tube M3 and the gate electrode of the NMOS tube M4 respectively, the drain electrode of the NMOS tube M15 is electrically connected with the main branch of the current mirror, the secondary branch of the current mirror is electrically connected with one end of the output resistor, and the current IP is output 4 ；
The source electrode of the NMOS tube M3 is electrically connected with the drain electrode of the NMOS tube M5, the source electrode of the NMOS tube M4 is electrically connected with the drain electrode of the NMOS tube M6, and the source electrode of the NMOS tube M15 is electrically connected with the drain electrode of the NMOS tube M16;
the grid electrode of the NMOS tube M5, the grid electrode of the NMOS tube M6 and the grid electrode of the NMOS tube M16 are electrically connected for accessing the control voltage V BN2 ；
The source electrode of the NMOS tube M5 is used for outputting current I P1 The source electrode of the NMOS tube M6 is used for outputting current I P2 The source electrode of the NMOS tube M16 outputs a current I P3 。
2. A wide voltage range current detection circuit according to claim 1 wherein said current I P1 And current I P2 Is the same size.
3. The wide voltage range current detection circuit according to claim 2, wherein the PMOS transistor M1 has the same size as the PMOS transistor M2, the NMOS transistor M3 has the same size as the NMOS transistor M4, and the NMOS transistor M5 has the same size as the NMOS transistor M6.
4. The wide voltage range current detection circuit of claim 1, wherein the current mirror comprises a PMOS transistor M13 and a PMOS transistor M14; the source electrode of the PMOS tube M13 is electrically connected with the source electrode of the PMOS tube M14 for accessing the power supply VCC, the grid electrode of the PMOS tube M13 is respectively electrically connected with the drain electrode of the PMOS tube M13, the drain electrode of the NMOS tube M15 and the grid electrode of the NMOS tube M14, and the drain electrode of the PMOS tube M14 outputs a current I P4 。
5. The current detection circuit with wide voltage range according to any one of claims 1 to 4, wherein the high voltage detection unit comprises a PMOS transistor M7, a PMOS transistor M8, an NMOS transistor M9, an NMOS transistor M10, an NMOS transistor M11, and an NMOS transistor M12;
the source electrode of the PMOS tube M7 is electrically connected with the other end of the first load resistor, the grid electrode of the PMOS tube M7 is electrically connected with the grid electrode of the PMOS tube M8, the drain electrode of the PMOS tube M7 and the drain electrode of the NMOS tube M9 respectively, the source electrode of the PMOS tube M8 is electrically connected with the other end of the second load resistor, and the drain electrode of the PMOS tube M8 is electrically connected with the drain electrode of the NMOS tube M10 and the control end of the control switch respectively;
the grid electrode of the NMOS tube M9 is electrically connected with the grid electrode of the NMOS tube M10 for accessing the control voltage V BN1 The source electrode of the NMOS tube M9 is electrically connected with the drain electrode of the NMOS tube M11, the drain electrode of the source NMOS tube M12 of the NMOS tube M10 is electrically connected, the grid electrode of the NMOS tube M11 is electrically connected with the grid electrode of the NMOS tube M12 for inputting the control voltage V BN0 The source electrode of the NMOS tube M11 and the source electrode of the NMOS tube M12 are grounded;
the current I N1 The current I is grounded through the PMOS tube M7, the NMOS tube M9 and the NMOS tube M11 N2 Through PMOS tube M8, NMOS tube M10 and NMOS tube M12, the ground connection.
6. The wide voltage range current detection circuit of claim 5 wherein the current I N1 And current IN 2 Is the same size.
7. The wide voltage range current detection circuit of claim 6, wherein the PMOS transistor M7 and the PMOS transistor M8 have the same size, the NMOS transistor M9 and the NMOS transistor M10 have the same size, and the NMOS transistor M11 and the NMOS transistor M12 have the same size.
8. The wide voltage range current detection circuit of claim 6, wherein the control switch is a PMOS transistor M17, a source of the PMOS transistor M17 is an input terminal of the control switch, a gate of the PMOS transistor M17 is a control terminal of the control switch, and a drain of the PMOS transistor M17 is an output terminal of the control switch.
9. A switching power supply comprising a wide voltage range current detection circuit as claimed in any one of claims 1 to 8.
CN202311670096.8A 2023-12-07 2023-12-07 Current detection circuit with wide voltage range and switching power supply Active CN117388561B (en)

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