Subcircuit model for improving reverse current characteristic of zener diode and construction method thereof

Abstract

The application discloses a sub-circuit model for improving reverse current characteristics of a Zener diode and a construction method thereof, and the method comprises the following steps: step 1, measuring the forward and reverse characteristics of the Zener diode, obtaining the corresponding data of the current Ij and the junction voltage Vj, and the voltage between the cathode n end and the anode p end; step 2, adjusting the model parameters to ensure that the simulation data of the forward current characteristics are consistent with the measured data, obtaining a mathematical expression of the relationship between the reverse current and the voltage between the cathode n end and the anode p end of the Zener diode by using a fitting method, and obtaining the reverse resistance value; and step 3, obtaining the resistance r1 for adjusting the reverse breakdown current according to the reverse resistance value, adding an intermediate terminal p1 in the atomic circuit model of the Zener diode, adding the resistance r1 for adjusting the reverse breakdown current between the anode p end of the Zener diode and the intermediate terminal p1 end, and keeping the original circuit between the intermediate terminal p1 end and the cathode n end of the Zener diode, so as to construct a new sub-circuit model.

Description

Technical Field

[0001] This invention relates to the field of semiconductor integrated circuit technology, and in particular to a sub-circuit model for improving the reverse current characteristics of a Zener diode and its construction method. Background Technology

[0002] Generally, both the forward conduction current and reverse breakdown current of a Zener diode are important considerations. However, existing models only have one resistance parameter, meaning they can only guarantee a one-sided match between simulation and measured data. For example... Figure 1 This is a comparison chart of simulation and measured data for the existing sub-circuit model. The horizontal axis represents the Zener diode junction voltage Vj (in V), and the vertical axis represents the current Ij flowing through the Zener diode (in A). The left side shows the forward conduction current, and the right side shows the reverse breakdown current characteristics. Figure 1 As shown, the simulated data (thin solid line) of the forward conduction current on the left matches the measured data (thick dots), but the simulated data of the reverse breakdown current characteristic on the right differs greatly from the measured data; or, adjusting the simulation parameters can ensure that the simulated data of the reverse breakdown current matches the measured data, but the forward conduction current characteristic differs greatly from the measured data. Summary of the Invention

[0003] To overcome the shortcomings of the existing technology, the purpose of this invention is to provide a sub-circuit model and its construction method for improving the reverse current characteristics of a Zener diode, so as to achieve the purpose of improving the reverse current characteristics of a Zener diode.

[0004] To achieve the above and other objectives, this invention proposes a method for constructing a sub-circuit model to improve the reverse current characteristics of a Zener diode, comprising the following steps:

[0005] Step 101: Measure the forward and reverse characteristics of the Zener diode, and obtain the corresponding data of current Ij and junction voltage Vj, and voltage v(n,p) between cathode n and anode p.

[0006] Step 102: Based on the measured data from step 101, adjust the model parameters to ensure that the simulated data and measured data of the forward current characteristics match. Then, use a fitting method to obtain a mathematical expression for the relationship between the reverse current when the reverse voltage is applied and the voltage v(n,p) between the cathode n-terminal and anode p-terminal of the Zener diode, thereby obtaining a reverse resistance value.

[0007] Step 103: Based on the reverse resistance value, obtain a resistor r1 for adjusting the reverse breakdown current. Add an intermediate terminal p1 to the atomic circuit model of the Zener diode. Add the resistor r1 for adjusting the reverse breakdown current between the anode p terminal and the intermediate terminal p1 of the Zener diode, while the intermediate terminal p1 and the cathode n terminal of the Zener diode maintain the original circuit, thus constructing a new sub-circuit model of the Zener diode.

[0008] Preferably, in step 102, when a reverse voltage is applied, the reverse resistance value r1 is r2 = rbv.

[0009] Preferably, in step 103, the resistance value of the resistor r1 used to adjust the reverse breakdown current is rbv*(sgn(v(n,p))+1) / 2, where the sign function sgn(x) returns 1 when x is greater than 0, returns 0 when x is equal to 0, and returns -1 when x is less than 0, and v(n,p) is the voltage between the n-terminal and p-terminal of the Zener diode.

[0010] Preferably, when the voltage between the cathode n-terminal and the anode p-terminal is positive, that is, when the Zener diode is reverse biased, the resistor r1 between the anode p-terminal and the intermediate terminal p1 used to adjust the reverse breakdown current is r2 = rbv, which is used to adjust the reverse breakdown current.

[0011] Preferably, when the voltage between the cathode n-terminal and the anode p-terminal is 0, the resistor r1 between the anode p-terminal and the intermediate terminal p1 used to adjust the reverse breakdown current is rbv / 2.

[0012] Preferably, when the voltage between the cathode n-terminal and the anode p-terminal is negative, i.e., when the Zener diode is forward biased, the resistor r1 between the anode p-terminal and the intermediate terminal p1 used to adjust the reverse breakdown current is 0, the circuit is equivalent to the original model, and the forward conduction current is still adjusted by the resistor adjustment parameter rs in the atomic circuit model.

[0013] To achieve the above objectives, the present invention also provides a sub-circuit model for improving the reverse current characteristics of a Zener diode. An intermediate terminal p1 is added to the atomic circuit model of the Zener diode, and a resistor r1 for adjusting the reverse breakdown current is added between the anode p terminal of the Zener diode and the intermediate terminal p1. The intermediate terminal p1 and the cathode n terminal of the Zener diode maintain the original circuit.

[0014] Preferably, the resistance value of the resistor r1 used to adjust the reverse breakdown current is rbv*(sgn(v(n,p))+1) / 2, where the sign function sgn(x) returns 1 when x is greater than 0, 0 when x is equal to 0, and -1 when x is less than 0, and v(n,p) is the voltage between the n-terminal and p-terminal of the Zener diode.

[0015] Compared with the prior art, the present invention provides a sub-circuit model and its construction method for improving the reverse current characteristics of a Zener diode. By adding an intermediate terminal p1 to the atomic circuit model of the Zener diode, a resistor r1 for adjusting the reverse breakdown current is added between the anode p terminal of the Zener diode and the intermediate terminal p1, while the intermediate terminal p1 and the cathode n terminal of the Zener diode maintain the original circuit, thereby constructing a new sub-circuit model that can improve the reverse current characteristics of the Zener diode. Attached Figure Description

[0016] Figure 1 A comparison chart of simulation data and measured data for an existing Zener diode sub-circuit model;

[0017] Figure 2 This is a flowchart illustrating the steps of constructing a sub-circuit model to improve the reverse current characteristics of a Zener diode according to the present invention.

[0018] Figure 3 This is a schematic diagram of the sub-circuit of the present invention;

[0019] Figure 4a This is the equivalent circuit diagram of the present invention;

[0020] Figure 4b This is the equivalent circuit diagram of the present invention in reverse;

[0021] Figure 4c This is the equivalent circuit diagram of the present invention in the forward direction;

[0022] Figure 5 This is a comparison chart of simulation data and measured data of the model of this invention. Detailed Implementation

[0023] The following describes the embodiments of the present invention through specific examples and in conjunction with the accompanying drawings. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific examples, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0024] Figure 2 This is a flowchart illustrating the steps of constructing a sub-circuit model for improving the reverse current characteristics of a Zener diode according to the present invention. Figure 2 As shown, the present invention provides a method for constructing a sub-circuit model to improve the reverse current characteristics of a Zener diode, comprising the following steps:

[0025] Step 101: Measure the forward and reverse characteristics of the device (Zener diode) and obtain the corresponding data of current Ij and junction voltage Vj. The voltage between the cathode n terminal and the anode p terminal is v(n,p) = -Vj.

[0026] Step 102: Based on the measured data from Step 101, adjust the model parameters to ensure that the simulated forward current characteristic data matches the measured data. Then, use a fitting method to obtain a mathematical expression for the relationship between the reverse current and the voltage v(n,p) between the cathode n-terminal and the anode p-terminal when a reverse voltage is applied, thereby obtaining... Figure 4b The reverse resistance r2, where the reverse resistance r2 = rbv;

[0027] Step 103: Add an intermediate terminal p1 to the atomic circuit model of the Zener diode. Add a resistor r1 between the anode p and the intermediate terminal p1 to adjust the reverse breakdown current. The intermediate terminal p1 and the cathode n maintain the original circuit, thus constructing the sub-circuit model of the Zener diode, as follows: Figure 3 As shown, the resistor r1 used to adjust the reverse breakdown current has a value of 'rbv*(sgn(v(n,p))+1) / 2'. The sign function sgn(x) returns 1 when x is greater than 0, 0 when x is equal to 0, and -1 when x is less than 0. v(n,p) is the voltage between the n and p terminals of the Zener diode. A specific example is shown below. Figure 4a -c indicates:

[0028] Figure 4a In the equivalent circuit of this invention, the circuit between terminals p and p1 consists of a second switch s2 connected in parallel, a resistor r2 connected in series, and a diode d2. The circuit between terminals p1 and n consists of a first switch s1 connected in parallel and a diode d1. Specifically, when the diode model is reverse-biased and cut off, the first switch s1 is on and the second switch s2 is off. Figure 4a Simplified to Figure 4b That is, when the diode model is reverse-biased, the model of this invention is equivalent to the original model d0 connected in series with a resistor r2; when the diode model is forward-biased, the first switch s1 is off and the second switch s2 is on. Figure 4a Simplified to Figure 4c That is, when the diode model is forward-biased, the model of this invention is consistent with the original model.

[0029] 1. When the voltage between the cathode n terminal and the anode p terminal is positive (i.e., the Zener diode is reverse biased), the resistor r1 between the anode p and the middle terminal p1 used to adjust the reverse breakdown current is equivalent to r2 = rbv, which is used to adjust the reverse breakdown current. The circuit is equivalent to the original model d0 series resistor r2.

[0030] 2. When the voltage between the cathode n terminal and the anode p terminal is 0, the resistor r1 between the anode p and the intermediate terminal p1 used to adjust the reverse breakdown current is equivalent to rbv / 2, but since the current itself is zero, it has no actual effect.

[0031] 3. When the voltage between the cathode n terminal and the anode p terminal is negative (i.e., the Zener diode is forward biased), the resistor r1 between the anode p and the middle terminal p1 used to adjust the reverse breakdown current is equivalent to 0, and the circuit is equivalent to the original model. The forward conduction current is still adjusted by the resistor adjustment parameter rs in the atomic circuit model.

[0032] The following is an example Spice model library file for constructing the new sub-circuit model of this invention:

[0033]

[0034] Here, rbv_1 is a constant whose value depends on the process parameters.

[0035] In a specific embodiment of the present invention, forward and reverse currents are simulated by adjusting parameters, and the simulated data is compared with measured data, such as... Figure 5 As shown, with Figure 1 In comparison, it is evident that the reverse current characteristics and data of the sub-circuit model constructed in this invention are more consistent.

[0036] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can make modifications and changes to the above embodiments without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be as set forth in the claims.

Claims

1. A method for constructing a subcircuit model for improving the reverse current characteristic of a Zener diode, comprising the following steps: Step 101, measuring the forward and reverse characteristics of the Zener diode, obtaining the corresponding data of current Ij and junction voltage Vj, and voltage v(n, p) between the cathode n end and the anode p end of the Zener diode; Step 102, according to the measured data of step 101, adjusting the model parameters to ensure that the simulated data of the forward current characteristic is consistent with the measured data, and then using a fitting method to obtain a mathematical expression of the relationship between the reverse current and the voltage v(n, p) between the cathode n end and the anode p end of the Zener diode when a reverse voltage is applied, thereby obtaining a reverse resistance value, wherein when a reverse voltage is applied, the reverse resistance value r2 = rbv; Step 103, according to the reverse resistance value, obtaining a resistance r1 for adjusting the reverse breakdown current, adding an intermediate terminal p1 in the atomic circuit model of the Zener diode, adding the resistance r1 for adjusting the reverse breakdown current between the anode p terminal of the Zener diode and the intermediate terminal p1 terminal, and keeping the original circuit between the intermediate terminal p1 terminal and the cathode n terminal of the Zener diode, constructing a new sub-circuit model of the Zener diode, wherein, The resistance value of the resistance r1 for adjusting the reverse breakdown current is rbv*(sgn(v(n, p))+1) / 2.

2. The method for constructing a sub-circuit model for improving the reverse current characteristic of a Zener diode according to claim 1, wherein: In step 103, the sign function sgn(x) returns 1 when x is greater than 0, returns 0 when x is equal to 0, and returns -1 when x is less than 0, and v(n, p) is the voltage between the n end and the p end of the Zener diode.

3. The method for constructing a sub-circuit model to improve the reverse current characteristics of a Zener diode as described in claim 2, characterized in that: When the voltage between the n end and the p end is positive, i.e. the Zener diode is reverse biased, the resistance r1 between the anode p end and the intermediate terminal p1 for adjusting the reverse breakdown current is r2 = rbv, which is used to adjust the reverse breakdown current.

4. The method for constructing a sub-circuit model to improve the reverse current characteristics of a Zener diode as described in claim 2, characterized in that: When the voltage between the n end and the p end is 0, the resistance r1 between the anode p end and the intermediate terminal p1 for adjusting the reverse breakdown current is rbv / 2.

5. The method for constructing a sub-circuit model to improve the reverse current characteristics of a Zener diode as described in claim 2, characterized in that: When the voltage between the n end and the p end is negative, i.e. the Zener diode is forward biased, the resistance r1 between the anode p end and the intermediate terminal p1 for adjusting the reverse breakdown current is 0, and the circuit is equivalent to the original model, and the forward conduction current is still adjusted by the resistance adjustment parameter rs in the original subcircuit model.

6. A sub-circuit for improving the reverse current characteristics of a Zener diode using the method of claim 1, characterized by: An intermediate terminal p1 is added to the original subcircuit model of the Zener diode, a resistance r1 for adjusting the reverse breakdown current is added between the anode p end of the Zener diode and the intermediate terminal p1, and the intermediate terminal p1 and the cathode n end of the Zener diode remain the original circuit.

7. The subcircuit for improving reverse current characteristics of a Zener diode according to claim 6, wherein: The sign function sgn(x) returns 1 when x is greater than 0, returns 0 when x is equal to 0, and returns -1 when x is less than 0, and v(n, p) is the voltage between the n end and the p end of the Zener diode.

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