Wilson current source circuit, pcb board and device for eliminating body effect
By constructing a combined structure of a resistive mirror section and a mirror section, the body effect of the MOSFET in the Wilson current source circuit is eliminated, the problems of threshold voltage offset and output current mismatch are solved, and the high accuracy and stability of the current reference are achieved, adapting to the low-voltage operating requirements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHUHAI CORE DISCOVERY MICROELECTRONICS CO LTD
- Filing Date
- 2025-12-12
- Publication Date
- 2026-07-14
Smart Images
Figure CN224501215U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of current source circuit technology, and in particular to a Wilson current source circuit, PCB board and device for eliminating body effect. Background Technology
[0002] Wilson current sources are commonly used current references and mirror structures in CMOS (Complementary Metal-Oxide-Semiconductor) integrated circuits. Their high output impedance effectively improves current transmission stability, making them widely used in analog and mixed-signal circuit designs. However, the performance of traditional structures is significantly limited by the bulk effect of MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors): the device threshold voltage shifts with the potential difference between the source and substrate, causing the threshold voltage of the matching device in the current mirror to deviate from design consistency. This ultimately leads to output current mismatch, resulting in large errors and severely reducing the accuracy of the circuit's current reference.
[0003] As integrated circuits evolve towards lower power consumption, the continuous reduction in power supply voltage further exacerbates the negative impact of the bulk effect: the fluctuation range of the source voltage relative to the power supply voltage increases, making the current mirror's transmission characteristics exhibit stronger nonlinearity, which significantly limits the circuit's low-voltage operating capability and makes it difficult to adapt to the design requirements of modern low-power systems.
[0004] To mitigate the effects of bulk effects, existing technologies have proposed strategies for fixing substrate bias. However, this method can only suppress bulk effects under specific source voltage conditions and cannot adapt to changes in source voltage during dynamic operation. In practical applications, its effect on improving current stability is limited. Another solution is to use SOI (Silicon-On-Insulator) technology, which uses an insulating buried layer to achieve electrical isolation between the device and the substrate to eliminate bulk effects. However, the manufacturing cost of this process is significantly higher than that of standard CMOS technology, and it is incompatible with the design and production processes of mainstream silicon technology, making it difficult to achieve widespread application in large-scale commercial circuits. Summary of the Invention
[0005] In order to overcome the shortcomings of the prior art, the purpose of this utility model is to provide a Wilson current source circuit that eliminates the body effect, which aims to suppress the body effect of MOSFET, reduce the threshold voltage offset of the current mirror and the output current mismatch, and control the current transmission error to a lower level.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A Wilson current source circuit for eliminating the body effect includes a resistive mirror section, a first mirror section, and a second mirror section. The resistive mirror section and the first mirror section are respectively connected to the second mirror section. The resistive mirror section includes a mirror tube, and the potential difference between the source of the mirror tube and the substrate is zero to eliminate the body effect. The first mirror section is used to mirror the current of the resistive mirror section to generate a mirrored current. The second mirror section is used to mirror the current of its own branch and merge with the mirrored current to output a target current.
[0008] In the Wilson current source circuit for eliminating the body effect, the resistive mirror section further includes a first negative feedback resistor R1. The mirror is a first PMOS transistor PM1. One end of the first negative feedback resistor R1 is connected to VDD, and the other end of the first negative feedback resistor R1 is connected to the source of the first PMOS transistor PM1. The substrate of the first PMOS transistor PM1 is connected to the source, the drain of the first PMOS transistor PM1 is connected to the second mirror section, and the gate of the first PMOS transistor PM1 is connected to the first mirror section.
[0009] In the Wilson current source circuit for eliminating the body effect, the first mirror section includes a second PMOS transistor PM2. The source and substrate of the second PMOS transistor PM2 are respectively connected to VDD, and the gate of the second PMOS transistor PM2 is connected to the drain, the gate of the first PMOS transistor PM1, and the second mirror section.
[0010] In the Wilson current source circuit for eliminating the body effect, the second mirror transistor section includes a first NMOS transistor NM1 and a second NMOS transistor NM2. The source and substrate of the first NMOS transistor NM1 and the source and substrate of the second NMOS transistor NM2 are respectively connected to VSS. The gate of the first NMOS transistor NM1 is connected to the drain, the gate of the second NMOS transistor NM2 and the drain of the first PMOS transistor PM1. The drain of the second NMOS transistor NM2 is connected to the drain of the second PMOS transistor PM2.
[0011] In the Wilson current source circuit for eliminating the body effect, the resistive mirror section further includes a second negative feedback resistor R2. The mirror is a third NMOS transistor NM3. One end of the second negative feedback resistor R2 is connected to the gate of the second mirror section and the gate of the third NMOS transistor NM3, respectively. The other end of the second negative feedback resistor R2 is connected to the drain of the third NMOS transistor NM3 and the first mirror section, respectively. The source and substrate of the third NMOS transistor NM3 are connected to VSS, respectively.
[0012] In the Wilson current source circuit for eliminating the body effect, the first mirror section includes a fourth NMOS transistor NM4, the source and substrate of the fourth NMOS transistor NM4 are respectively connected to VSS, the gate of the fourth NMOS transistor NM4 is connected to the drain of the third NMOS transistor NM3, and the drain of the fourth NMOS transistor NM4 is connected to the second mirror section.
[0013] In the Wilson current source circuit for eliminating the body effect, the second mirror section includes a third PMOS transistor PM3 and a fourth PMOS transistor PM4. The source and substrate of the third PMOS transistor PM3 and the source and substrate of the fourth PMOS transistor PM4 are respectively connected to VDD. The drain of the third PMOS transistor PM3 is connected to one end of the second negative feedback resistor R2. The gate of the fourth PMOS transistor PM4 is connected to the drain, the gate of the third PMOS transistor PM3, and the drain of the fourth NMOS transistor NM4.
[0014] The present invention also provides a PCB board, on which the Wilson current source circuit for eliminating the body effect as described above is printed.
[0015] This invention also provides an electronic device, which uses the Wilson current source circuit described above to eliminate the body effect for operation control.
[0016] Beneficial effects:
[0017] This invention provides a Wilson current source circuit that eliminates the body effect, including a resistive mirror section, a first mirror section, and a second mirror section. The resistive mirror section and the first mirror section are respectively connected to the second mirror section. The resistive mirror section includes a mirror transistor, and the potential difference between the source of the mirror transistor and the substrate is zero to eliminate the body effect. The first mirror section is used to mirror the current of the resistive mirror section to generate a mirror current. The second mirror section is used to mirror the current of its own branch and merge with the mirror current to output the target current. The potential difference between the source of the mirror transistor and the substrate in the resistive mirror section is set to zero, which suppresses the body effect of the MOSFET from the root, effectively reduces the impact of threshold voltage offset on current transmission, significantly reduces the output current mismatch of the current mirror, and significantly improves the accuracy and stability of the current reference. Attached Figure Description
[0018] Figure 1 A circuit block diagram of the Wilson current source circuit for eliminating the body effect provided by this utility model;
[0019] Figure 2 A circuit diagram of a Wilson current source circuit for eliminating body effect provided by this utility model;
[0020] Figure 3 The circuit diagram of another Wilson current source circuit for eliminating the body effect provided by this utility model.
[0021] Explanation of key component symbols: 100 - resistive image tube section, 200 - first image tube section, 300 - second image tube section. Detailed Implementation
[0022] This utility model provides a Wilson current source circuit, PCB board, and device for eliminating volume effects. To make the purpose, technical solution, and effects of this utility model clearer and more explicit, the following describes this utility model in further detail with reference to the accompanying drawings and examples.
[0023] In the description of this utility model, it should be understood that the terms "installation" and "connection" should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0024] Please see Figure 1 This invention provides a Wilson current source circuit for eliminating the body effect, including a resistive mirror section 100, a first mirror section 200, and a second mirror section 300. The resistive mirror section 100 and the first mirror section 200 are respectively connected to the second mirror section 300. The resistive mirror section 100 includes a mirror tube, and the potential difference between the source of the mirror tube and the substrate is zero to eliminate the body effect. The first mirror section 200 is used to mirror the current of the resistive mirror section 100 to generate a mirrored current. The second mirror section 300 is used to mirror the current of its own branch and merge with the mirrored current to output a target current.
[0025] In a traditional Wilson current source, the negative feedback resistor is placed at the source of the NMOS transistor in the output branch. The voltage drop it generates will cause the potential difference between the source of the NMOS transistor and the substrate to be non-zero. The body effect will change its threshold voltage. This deviation of the threshold voltage will destroy the matching between the current mirror devices, resulting in a significant deviation between the output current and the ideal value. At the same time, the voltage drop of the negative feedback resistor will occupy the power supply voltage margin and limit the low-voltage operation capability of the circuit.
[0026] To address the aforementioned issues, the Wilson current source circuit for eliminating the bulk effect disclosed in this application constructs a combined structure of a resistive mirror section 100, a first mirror section 200, and a second mirror section 300. Resistors and mirrors are integrated into the resistive mirror section 100. By adjusting the resistor position, the potential of the mirror's source is kept consistent with the substrate potential, fundamentally eliminating the potential difference between its source and substrate. This avoids the modulation of the device's threshold voltage by the bulk effect, directly solving the core problem of inconsistent threshold voltages in traditional circuits. Furthermore, the first mirror section 200, through a current mirror structure, achieves stable current transfer from the resistive mirror section 100 to the mirrored current. The second mirror section 300, through the current mirroring of its own branch, merges with the mirrored current of the first mirror section 200 at the output node to form the target current, ensuring the continuity and matching of current transfer.
[0027] Further, please refer to Figure 1 and Figure 2 In the Wilson current source circuit for eliminating the body effect, the resistive mirror section 100 further includes a first negative feedback resistor R1. The mirror is a first PMOS transistor PM1. One end of the first negative feedback resistor R1 is connected to VDD, and the other end of the first negative feedback resistor R1 is connected to the source of the first PMOS transistor PM1. The substrate of the first PMOS transistor PM1 is connected to the source. The drain of the first PMOS transistor PM1 is connected to the second mirror section 300, and the gate of the first PMOS transistor PM1 is connected to the first mirror section 200.
[0028] The Wilson current source circuit for eliminating the body effect disclosed in this application includes a first negative feedback resistor R1, one end of which is connected to the power supply VDD, and the other end is connected to the source of a first PMOS transistor PM1. Simultaneously, the substrate of the first PMOS transistor PM1 is directly connected to its own source. This design leverages the adjustable substrate potential of PMOS devices in CMOS technology to maintain a zero potential difference between the source and substrate of the first PMOS transistor PM1, thereby eliminating the body effect at its source and preventing its threshold voltage from shifting due to the potential difference between the source and substrate. Through the equipotential configuration of the substrate and source of the first PMOS transistor PM1, its threshold voltage is effectively stabilized, reducing the interference of the body effect on device characteristics, improving the characteristic matching accuracy between current mirror devices, and thus reducing the mismatch error of the output current and enhancing the accuracy of the current reference. The layout of the first negative feedback resistor R1 not only plays a stabilizing role for the reference current but also avoids the resistor generating an additional voltage drop in the output branch, optimizing the voltage operating margin of the circuit and expanding its adaptability for low-voltage operation.
[0029] It should be clarified that although this configuration achieves the suppression of the bulk effect, the independent potential design of the substrate and source of the first PMOS transistor PM1 requires the separate setting of a well region for it during the layout process. This increases the design complexity of the layout and raises the cost and difficulty of the design process. At the same time, the separate well structure will cause the process growth environment of the first PMOS transistor PM1 and the corresponding device in the first mirror transistor section 200 to differ, which will disrupt the consistency of the process conditions between the two and thus lose the matching accuracy between the devices, which will have a certain adverse effect on the current replication accuracy of the current mirror.
[0030] Further, please refer to Figure 1 and Figure 2 In the Wilson current source circuit for eliminating body effect, the first mirror section 200 includes a second PMOS transistor PM2, the source and substrate of the second PMOS transistor PM2 are respectively connected to VDD, and the gate of the second PMOS transistor PM2 is connected to the drain, the gate of the first PMOS transistor PM1 and the second mirror section 300.
[0031] Further, please refer to Figure 1 and Figure 2 In the Wilson current source circuit for eliminating the body effect, the second mirror transistor section 300 includes a first NMOS transistor NM1 and a second NMOS transistor NM2. The source and substrate of the first NMOS transistor NM1 and the source and substrate of the second NMOS transistor NM2 are respectively connected to VSS. The gate of the first NMOS transistor NM1 is connected to the drain, the gate of the second NMOS transistor NM2 and the drain of the first PMOS transistor PM1. The drain of the second NMOS transistor NM2 is connected to the drain of the second PMOS transistor PM2. The second NMOS transistor NM2 is used to mirror the current of the first NMOS transistor NM1 and merge with the mirrored current to output the target current.
[0032] Further, please refer to Figure 1 and Figure 3 In the Wilson current source circuit for eliminating the body effect, the resistive mirror section 100 further includes a second negative feedback resistor R2. The mirror is a third NMOS transistor NM3. One end of the second negative feedback resistor R2 is connected to the gate of the second mirror section 300 and the gate of the third NMOS transistor NM3, respectively. The other end of the second negative feedback resistor R2 is connected to the drain of the third NMOS transistor NM3 and the first mirror section 200, respectively. The source and substrate of the third NMOS transistor NM3 are connected to VSS, respectively.
[0033] The Wilson current source circuit for eliminating the body effect disclosed in this application connects one end of the second negative feedback resistor R2 to both the gate of the second mirror transistor 300 and the gate of the third NMOS transistor NM3, and the other end to the drain of the third NMOS transistor NM3 and the first mirror transistor 200, thus constructing a drain negative feedback topology, replacing the traditional source negative feedback structure. The source and substrate of the third NMOS transistor NM3 are directly connected to VSS, ensuring that the potential difference between the source and substrate of the device remains zero, avoiding device mismatch caused by threshold voltage deviation, significantly improving the current replication accuracy of the current mirror, and making the output current closer to the ideal calculated value. The drain negative feedback topology retains the stabilizing effect of negative feedback on the current, eliminates the need for separate well regions for specific devices, avoids the design complexity caused by additional layout processing, and ensures the consistency of the process growth environment for each device, further enhancing the matching accuracy between devices.
[0034] Further, please refer to Figure 1 and Figure 3 In the Wilson current source circuit for eliminating body effect, the first mirror section 200 includes a fourth NMOS transistor NM4, the source and substrate of the fourth NMOS transistor NM4 are respectively connected to VSS, the gate of the fourth NMOS transistor NM4 is connected to the drain of the third NMOS transistor NM3, and the drain of the fourth NMOS transistor NM4 is connected to the second mirror section 300.
[0035] The Wilson current source circuit disclosed in this application, which eliminates the body effect, has its source of the fourth NMOS transistor NM4 directly connected to VSS, and the substrate is also connected to VSS. The potentials of the source and the substrate are both VSS, and there is no potential difference between them. Therefore, the potential difference between the source of the fourth NMOS transistor NM4 and the substrate is zero, which eliminates the body effect of the fourth NMOS transistor NM4 participating in the current mirror. This significantly improves the current replication accuracy of the current mirror, reduces the mismatch error of the output current, makes the current output closer to the ideal calculated value, and enhances the accuracy of the circuit as a current reference.
[0036] Further, please refer to Figure 1 and Figure 3In the Wilson current source circuit for eliminating the body effect, the second mirror transistor section 300 includes a third PMOS transistor PM3 and a fourth PMOS transistor PM4. The source and substrate of the third PMOS transistor PM3 and the source and substrate of the fourth PMOS transistor PM4 are respectively connected to VDD. The drain of the third PMOS transistor PM3 is connected to one end of the second negative feedback resistor R2. The gate of the fourth PMOS transistor PM4 is connected to the drain, the gate of the third PMOS transistor PM3, and the drain of the fourth NMOS transistor NM4. The fourth NMOS transistor NM4 is used to mirror the current of the third PMOS transistor PM3 and merge with the mirrored current to output the target current.
[0037] The Wilson current source circuit for eliminating the body effect disclosed in this application has its sources directly connected to VDD for both the third PMOS transistor PM3 and the fourth PMOS transistor PM4, and the substrate is also connected to VDD. The source potential and substrate potential of both are VDD. Therefore, the potential difference between the source and substrate of the third PMOS transistor PM3 and the fourth PMOS transistor PM4 is zero, which eliminates the body effect of the third PMOS transistor PM3 and the fourth PMOS transistor PM4 participating in the current mirror. This significantly improves the current replication accuracy of the current mirror, reduces the mismatch error of the output current, makes the current output closer to the ideal calculated value, and enhances the accuracy of the circuit as a current reference.
[0038] This application discloses two Wilson current source circuits for eliminating the body effect. In the first circuit, one end of the first negative feedback resistor R1 is connected to VDD, and the other end is connected to the source of the first PMOS transistor PM1. The substrate of the first PMOS transistor PM1 must be connected to its own source. The negative feedback topology of this circuit is source negative feedback, and the resistor is configured in the source branch of the first PMOS transistor PM1. Although the body effect of the first PMOS transistor PM1 is eliminated, the connection between the substrate and the source of the first PMOS transistor PM1 deviates from the standard CMOS process specification that the PMOS substrate is connected to VDD by default. A separate well region needs to be set for it. This increases the complexity of the layout and also disrupts the consistency of the process growth environment between the first PMOS transistor PM1 and the second PMOS transistor PM2 in the first mirror transistor section 200, thereby losing the matching between devices. Matching accuracy; In the second circuit, one end of the second negative feedback resistor R2 is connected to both the gate of the second mirror transistor 300 and the gate of the third NMOS transistor NM3, and the other end is connected to the drain of the third NMOS transistor NM3 and the first mirror transistor 200. The substrate of the third NMOS transistor NM3 is directly connected to VSS. The negative feedback topology of this circuit is drain negative feedback, and the resistor is configured at the drain node of the third NMOS transistor NM3. At the same time, the substrate configuration of all devices conforms to the standard CMOS process specifications. The substrate and source of the PMOS device are both connected to VDD, and the substrate and source of the NMOS device are both connected to VSS. The potential difference between the source and substrate of all MOS devices participating in the current mirror is zero, which eliminates the modulation effect of the body effect on the threshold voltage of each device. No additional layout processing is required, which simplifies the design process, ensures the consistency of the process growth environment between devices, and improves the matching accuracy.
[0039] The present invention also provides a PCB board, on which the Wilson current source circuit for eliminating the body effect as described above is printed.
[0040] This invention also provides an electronic device, which uses the Wilson current source circuit described above to eliminate the body effect for operation control.
[0041] It is understood that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of this utility model, and all such substitutions or changes should fall within the protection scope of this utility model.
Claims
1. A Wilson current source circuit for eliminating volume effects, characterized in that, The device includes a resistive mirror section, a first mirror section, and a second mirror section. The resistive mirror section and the first mirror section are respectively connected to the second mirror section. The resistive mirror section includes a mirror tube, and the potential difference between the source of the mirror tube and the substrate is zero to eliminate the bulk effect. The first mirror section is used to mirror the current of the resistive mirror section to generate a mirror current. The second mirror section is used to mirror the current of its own branch and merge with the mirror current to output the target current.
2. The Wilson current source circuit for eliminating volume effect according to claim 1, characterized in that, The resistive mirror section further includes a first negative feedback resistor R1. The mirror is a first PMOS transistor PM1. One end of the first negative feedback resistor R1 is connected to VDD, and the other end of the first negative feedback resistor R1 is connected to the source of the first PMOS transistor PM1. The substrate of the first PMOS transistor PM1 is connected to the source, the drain of the first PMOS transistor PM1 is connected to the second mirror section, and the gate of the first PMOS transistor PM1 is connected to the first mirror section.
3. The Wilson current source circuit for eliminating volume effect according to claim 2, characterized in that, The first mirror section includes a second PMOS transistor PM2, the source and substrate of the second PMOS transistor PM2 are respectively connected to VDD, and the gate of the second PMOS transistor PM2 is connected to the drain, the gate of the first PMOS transistor PM1 and the second mirror section.
4. The Wilson current source circuit for eliminating volume effect according to claim 3, characterized in that, The second mirror transistor section includes a first NMOS transistor NM1 and a second NMOS transistor NM2. The source and substrate of the first NMOS transistor NM1 and the source and substrate of the second NMOS transistor NM2 are respectively connected to VSS. The gate of the first NMOS transistor NM1 is connected to the drain, the gate of the second NMOS transistor NM2 and the drain of the first PMOS transistor PM1. The drain of the second NMOS transistor NM2 is connected to the drain of the second PMOS transistor PM2.
5. The Wilson current source circuit for eliminating volume effect according to claim 1, characterized in that, The resistive mirror section further includes a second negative feedback resistor R2. The mirror is a third NMOS transistor NM3. One end of the second negative feedback resistor R2 is connected to the gate of the second mirror section and the gate of the third NMOS transistor NM3, respectively. The other end of the second negative feedback resistor R2 is connected to the drain of the third NMOS transistor NM3 and the first mirror section, respectively. The source and substrate of the third NMOS transistor NM3 are connected to VSS, respectively.
6. The Wilson current source circuit for eliminating volume effects according to claim 5, characterized in that, The first mirror section includes a fourth NMOS transistor NM4, the source and substrate of the fourth NMOS transistor NM4 are respectively connected to VSS, the gate of the fourth NMOS transistor NM4 is connected to the drain of the third NMOS transistor NM3, and the drain of the fourth NMOS transistor NM4 is connected to the second mirror section.
7. The Wilson current source circuit for eliminating volume effects according to claim 6, characterized in that, The second mirror transistor section includes a third PMOS transistor PM3 and a fourth PMOS transistor PM4. The source and substrate of the third PMOS transistor PM3 and the source and substrate of the fourth PMOS transistor PM4 are respectively connected to VDD. The drain of the third PMOS transistor PM3 is connected to one end of the second negative feedback resistor R2. The gate of the fourth PMOS transistor PM4 is connected to the drain, the gate of the third PMOS transistor PM3 and the drain of the fourth NMOS transistor NM4.
8. A PCB board, characterized in that, The PCB board is printed with a Wilson current source circuit for eliminating body effects as described in any one of claims 1-7.
9. An electronic device, characterized in that, The electronic device employs a Wilson current source circuit that eliminates volume effects as described in any one of claims 1-7 for operation control.