A bandgap reference circuit resistant to total dose radiation

Abstract

The present application belongs to the field of analog integrated circuit anti-radiation reinforcement technology, and relates to a band gap reference circuit resistant to total dose radiation, which is divided into PMOS type band gap reference and isolated NMOS type band gap reference. The circuit is characterized in that: MOS tubes in the circuit work in the cut-off region, and the drain and body potentials are connected, and a band gap reference voltage is generated by using the source-well diode. In the device structure, the source-well diode is far away from the field oxide region by using the interdigital structure, so that the total dose radiation interference is avoided to the greatest extent. The present application has the advantages of resistance to total dose radiation, small layout area, strong portability and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of analog integrated circuit anti-radiation reinforcement, and particularly relates to a bandgap reference circuit resistant to total dose radiation. BACKGROUND

[0002] The bandgap reference circuit is widely applied to analog or digital-analog hybrid integrated circuits such as state monitoring, power management, analog-digital / digital-analog converters, and the like due to good robustness to power voltage, process parameters and temperature changes. In the field of aviation and aerospace, the radiation environment can cause degradation of transistor performance, and the reference voltage will be significantly offset after long-term accumulation, which affects the normal work of other circuit modules, and may even cause the entire system to be paralyzed. Nowadays, the competition in the space field is becoming more and more fierce, and higher requirements are put forward for the anti-radiation performance of the bandgap reference circuit.

[0003] The traditional bipolar transistor will cause the base leakage current to increase and the gain to decrease in the total dose radiation environment, and the traditional diode will also cause the I / V characteristic to change due to field oxide trapping holes, both of which are not suitable for the reference circuit in the radiation environment. The MOS in the sub-threshold region can avoid the above situations, but its process stability is poor and cannot meet the accuracy requirements of the reference. In recent years, scholars have used closed gate DTMOS to complete the anti-radiation reinforcement and achieved good results, but special processing is required for the layout, and the portability is poor. SUMMARY

[0004] The purpose of the application is to solve the above problems, and a simple and practical bandgap reference circuit resistant to total dose radiation and a corresponding device structure are proposed on the basis of a typical commercial process.

[0005] To achieve the above purpose, the application adopts the following technical solutions:

[0006] The application discloses a total dose radiation resistant bandgap reference circuit which can be divided into two types of PMOS type bandgap reference and isolated NMOS type bandgap reference. The PMOS type bandgap reference comprises a first PMOS tube PM1, a second PMOS tube PM2, a first resistor R1, a second resistor R2, a first current source I1 and a second current source I2. The body potential of the first PMOS tube PM1 is connected with the drain, and the upper end of the second resistor R2 is connected; the source of the first PMOS tube PM1 is connected with the lower end of the first current source I1; the body potential of the second PMOS tube PM2 is connected with the drain, and the upper end of the second resistor R2 is connected; the source of the second PMOS tube PM2 is connected with the lower end of the first resistor R1; the upper end of the first resistor R1 is connected with the lower end of the second current source I2; the upper ends of the first current source I1 and the second current source I2 are connected with a power supply VDD, and the lower end of the second resistor R2 is connected with a ground potential GND; the gate potential of the first PMOS tube PM1 and the second PMOS tube PM2 is greater than or equal to the source potential; the current of the first current source I1 is equal to that of the second current source I2; the source potential of the first PMOS tube PM1 is equal to the upper end potential of the first resistor R1; the quantity ratio of the first PMOS tube PM1 to the second PMOS tube PM2 is 1:N (the second PMOS tube refers to a branch composed of a plurality of same PMOSs in series); and the source of the first PMOS tube PM1 is the output end of the bandgap reference circuit.

[0007] The isolated NMOS type bandgap reference comprises a first isolated NMOS tube NM1, a second isolated NMOS tube NM2, a first resistor R1, a second resistor R2, a first current source I1 and a second current source I2. The body potential of the first isolated NMOS tube NM1 is connected with the drain, and the lower end of the first current source I1 is connected; the source of the first isolated NMOS tube NM1 is connected with the upper end of the second resistor R2; the body potential of the second isolated NMOS tube NM2 is connected with the drain, and the lower end of the first resistor R1 is connected; the source of the second isolated NMOS tube NM2 is connected with the upper end of the second resistor R2; the upper end of the first resistor R1 is connected with the lower end of the second current source I2; the upper ends of the first current source I1 and the second current source I2 are connected with a power supply VDD, and the lower end of the second resistor R2 is connected with a ground potential GND; the gate potential of the first isolated NMOS tube NM1 and the second isolated NMOS tube NM2 is less than or equal to the source potential; the current of the first current source I1 is equal to that of the second current source I2; the drain potential of the first isolated NMOS tube NM1 is equal to the upper end potential of the first resistor R1; the quantity ratio of the first isolated NMOS tube NM1 to the second isolated NMOS tube NM2 is 1:N (the second isolated NMOS tube refers to a branch composed of a plurality of same isolated NMOSs in series); and the drain of the first isolated NMOS tube NM1 is the output end of the bandgap reference circuit.

[0008] The device structure of the first PMOS tube PM1 (or the second PMOS tube PM2, the first isolation NMOS tube NM1, or the second isolation NMOS tube NM2) adopts a finger structure, the number of fingers can be even numbers such as two, four, six, etc., the drain and the body potential are connected, the drain active area is close to the field oxide on both sides, and the source active area is far from the field oxide in the middle.

[0009] It should be stated that the first PMOS tube PM1 and the second PMOS tube PM2 (or the first isolation NMOS tube NM1 and the second isolation NMOS tube NM2) in the application can replace most bandgap reference circuits built with bipolar transistors / conventional diodes as the core, and the above-described examples only explain the application and are not limited to the application.

[0010] Compared with the prior art, the application has the beneficial effects that: the application proposes a bandgap reference circuit and a corresponding device structure resistant to total dose radiation, avoids the influence of total dose radiation, and can be applied in the field of aerospace; since no bipolar transistor or conventional diode is used, the layout area is small, and the cost is saved; the application has strong portability, does not require special layout structure, and can replace most bandgap reference circuits built with bipolar transistors or conventional diodes as the core. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 A bandgap reference circuit resistant to total dose radiation is proposed in the application;

[0012] Figure 2 A device structure schematic diagram of the PM1 (or PM2) tube (for example, finger=2);

[0013] Figure 3 A device structure schematic diagram of the NM1 (or NM2) tube (for example, finger=2);

[0014] Figure 4 A temperature characteristic schematic diagram of a bandgap reference circuit (PMOS type) resistant to total dose radiation proposed in the application under different process angles;

[0015] Figure 5 A temperature characteristic schematic diagram of a bandgap reference circuit (isolated NMOS type) resistant to total dose radiation proposed in the application under different process angles. DETAILED DESCRIPTION

[0016] Figure 1 A bandgap reference circuit resistant to total dose radiation is proposed in the application, which includes a PMOS type bandgap reference and an isolated NMOS type bandgap reference. The specific connection relationship has been described in detail in the summary of the application, and will not be described here.

[0017] The specific working principle of the present application is:

[0018] The anti-total dose radiation bandgap reference circuit (PMOS type) comprises a first PMOS tube PM1, a second PMOS tube PM2, a first resistor R1, a second resistor R2, a first current source I1 and a second current source I2. The first PMOS tube PM1 and the second PMOS tube PM2 work in the cutoff region, and the drain and the body potential are connected, so that the source well body diode is turned on, and the turn-on voltage has a negative temperature characteristic. The node V x , V y can be clamped to be equal by using an operational amplifier and the like structure, because the branch currents of PM1 and PM2 are equal, so the voltage drop on the first resistor R1 is:

[0019]

[0020] wherein is the thermal voltage. It can be seen that the voltage on the first resistor R1 has a positive temperature characteristic, and the final reference voltage output is:

[0021]

[0022] The anti-total dose radiation bandgap reference circuit (isolated NMOS type) comprises a first isolated NMOS tube NM1, a second isolated NMOS tube NM2, a first resistor R1, a second resistor R2, a first current source I1 and a second current source I2. The first isolated NMOS tube NM1 and the second isolated NMOS tube NM2 work in the cutoff region, and the drain and the body potential are connected, so that the well source body diode is turned on, and the turn-on voltage has a negative temperature characteristic. The node V x , V y can be clamped to be equal by using an operational amplifier and the like structure, because the branch currents of NM1 and NM2 are equal, so the voltage drop on the first resistor R1 is:

[0023]

[0024] It can be seen that the voltage on the first resistor R1 has a positive temperature characteristic, and the final reference voltage output is:

[0025]

[0026] Figure 2 The device structure diagram of the PM1 (or PM2) tube (taking finger=2 as an example), the layout adopts an interdigital structure, the drain active area close to the field oxide on both sides is the source active area far away from the field oxide in the middle.

[0027] Figure 3For the device structure schematic diagram of the NM1 (or NM2) tube, similarly, the layout adopts the interdigital structure, the drain active area is close to the field oxide on both sides, and the source active area is far away from the field oxide in the middle.

[0028] Figure 4 A temperature characteristic schematic diagram of a total dose radiation resistant bandgap reference circuit (PMOS type) proposed in the application under different process angles is shown in the figure, and the maximum voltage difference is only 5.306 mV in the typical process range of-45 DEG C to 125 DEG C.

[0029] Figure 5 A temperature characteristic schematic diagram of a total dose radiation resistant bandgap reference circuit (isolated NMOS type) proposed in the application under different process angles is shown in the figure, and the maximum voltage difference is only 3.669 mV in the typical process range of-45 DEG C to 125 DEG C.

[0030] In summary, the application provides a total dose radiation resistant bandgap reference circuit, which works in the cut-off region of the MOS tube, and the drain well is short-circuited, and the bandgap reference voltage is generated by using the source well diode. The interdigital structure is used on the device, so that the source well diode is far away from the field oxide area, and the total dose radiation interference is avoided to the greatest extent. The application has the advantages of total dose radiation resistance, small layout area, strong portability and the like.

Claims

1. A bandgap reference circuit resistant to total dose radiation, which is a PMOS type bandgap reference, characterized in that, This includes a first PMOS transistor PM1, a second PMOS transistor PM2, a first resistor R1, a second resistor R2, a first current source I1, and a second current source I2. The body potential and drain of the first PMOS transistor PM1 are connected, and it is also connected to the upper end of the second resistor R2. The source of the first PMOS transistor PM1 is connected to the lower end of the first current source I1. The body potential and drain of the second PMOS transistor PM2 are connected, and it is also connected to the upper end of the second resistor R2. The source of the second PMOS transistor PM2 is connected to the lower end of the first resistor R1. The upper end of the first resistor R1 is connected to the second current source I2.

2. Lower end; The upper ends of the first current source I1 and the second current source I2 are simultaneously connected to the power supply VDD, and the lower end of the second resistor R2 is connected to the ground potential GND; The gate potentials of the first PMOS transistor PM1 and the second PMOS transistor PM2 are greater than or equal to their respective source potentials; The currents of the first current source I1 and the second current source I2 are equal; The source potential of the first PMOS transistor PM1 is equal to the potential at the upper end of the first resistor R1; The ratio of the number of first PMOS transistors PM1 to the number of second PMOS transistors PM2 is 1:N; The source of the first PMOS transistor PM1 is the output terminal of the bandgap reference circuit.

2. The bandgap reference circuit resistant to total dose radiation according to claim 1, characterized in that, The first PMOS transistor PM1 and the second PMOS transistor PM2 adopt an interdigitated structure with an even number of fingers. The two sides closer to the field oxide are the drain active regions, and the middle part farther away from the field oxide is the source active region.

3. A bandgap reference circuit resistant to total dose radiation, which is an isolated NMOS type bandgap reference, characterized in that, This includes a first isolated NMOS transistor NM1, a second isolated NMOS transistor NM2, a first resistor R1, a second resistor R2, a first current source I1, and a second current source I2. The body potential and drain of the first isolated NMOS transistor NM1 are connected, and it is also connected to the lower end of the first current source I1. The source of the first isolated NMOS transistor NM1 is connected to the upper end of the second resistor R2. The body potential and drain of the second isolated NMOS transistor NM2 are connected, and it is also connected to the lower end of the first resistor R1. The source of the second isolated NMOS transistor NM2 is connected to the upper end of the second resistor R2. The upper end of the first resistor R1 is connected to the second current source I2.

2. Lower end; The upper ends of the first current source I1 and the second current source I2 are simultaneously connected to the power supply VDD, and the lower end of the second resistor R2 is connected to the ground potential GND; The gate potentials of the first isolated NMOS transistor NM1 and the second isolated NMOS transistor NM2 are less than or equal to their respective source potentials; The currents of the first current source I1 and the second current source I2 are equal; The drain potential of the first isolated NMOS transistor NM1 is equal to the potential at the upper end of the first resistor R1; The ratio of the number of first isolated NMOS transistors NM1 to the number of second isolated NMOS transistors NM2 is 1:N; The drain of the first isolated NMOS transistor NM1 is the output terminal of the bandgap reference circuit.

4. The bandgap reference circuit resistant to total dose radiation according to claim 3, characterized in that, The first isolation NMOS transistor NM1 and the second isolation NMOS transistor NM2 adopt an interdigitated structure with an even number of fingers. The two sides closer to the field oxide are the drain active regions, and the middle part farther away from the field oxide is the source active region.

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