Current frequency conversion circuit and implementation method

Abstract

The invention provides a current frequency conversion circuit and an implementation method. The current frequency conversion circuit comprises a positive channel threshold comparison circuit, a negative channel threshold comparison circuit, a positive channel logic control circuit, a channel logic control circuit, an integrating circuit, a constant current source, a first switch, a second switch and a third switch. Whether a positive constant current source or a negative constant current source needs to be used is judged through a positive and negative channel threshold comparator; the first switch and the second switch are controlled to be switched on and switched off to achieve different modes of intervening the integrating capacitor, so that the constant current source can be positive or negative. According to the invention, the problem of high power consumption of a current frequency conversion circuit is solved through a single constant current source; the problem that the positive constant current source and the negative constant current source have two adaptive references is also solved, and the problem of symmetry in the current frequency conversion circuit can be better solved; meanwhile, the circuit is simple in structure and low in cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical engineering applications, and in particular relates to a current frequency conversion circuit and an implementation method thereof. Background Art

[0002] In the inertial navigation system, the quartz flexible accelerometer outputs a current signal, which can be converted into corresponding acceleration information after passing through the corresponding conversion circuit. Combined with the current domestic chip technology level, the current frequency conversion circuit is still the mainstream circuit of the conversion circuit, which is mainly composed of a current integration circuit, a threshold comparison circuit, a logic control circuit, a positive constant current source module, a negative constant current source module and an analog electronic switch.

[0003] Among them, the positive and negative constant current sources are used to accurately quantify the amount of charge in the integrator, and they have the characteristic of working at different times. In order to ensure the accuracy of the current-frequency conversion circuit in engineering applications, it is often necessary to keep the positive constant current source module and the negative constant current source module working all the time. This method has some practical problems:

[0004] 1. In the process of engineering application, in order to avoid the instability caused by the constant current source establishment time, the positive and negative constant current sources need to be established all the time, so in the current frequency conversion circuit with a large range, a lot of power consumption will be generated;

[0005] 2. Since the positive and negative constant current sources use two adapted reference power supplies, there is a certain error between the positive and negative references, resulting in poor inherent symmetry of the current-frequency conversion circuit;

[0006] 3. The positive and negative constant current sources require two sets of symmetrical circuit designs, so they take up a large space, which is not conducive to the current trend of miniaturization. Summary of the invention

[0007] The purpose of the present invention is to provide a current-frequency conversion circuit and an implementation method to reduce circuit power consumption in view of the deficiencies in the prior art.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A current frequency conversion circuit includes a positive channel threshold comparison circuit, a negative channel threshold comparison circuit, a positive channel logic control circuit, a negative channel logic control circuit, and an integration circuit;

[0010] Also includes a constant current source, a first switch, a second switch, and a third switch;

[0011] The output end of the constant current source is respectively connected to the first end of the first switch, the first end of the second switch, and the first end of the third switch;

[0012] The second end of the third switch is grounded;

[0013] The second end of the first switch is connected to the first end of the integration circuit, and the second end of the second switch is connected to the second end of the integration circuit;

[0014] The third terminal of the integration circuit is connected to the first terminal of the positive channel threshold comparison circuit and the first terminal of the negative channel threshold comparison circuit respectively;

[0015] The second end of the positive channel threshold comparison circuit is connected to the positive channel logic control circuit;

[0016] The second end of the negative channel threshold comparison circuit is connected to the negative channel logic control circuit;

[0017] The constant current source provides a positive constant current source or a negative constant current source for the integration circuit through the first switch and the second switch;

[0018] The positive channel threshold comparison circuit and the negative channel threshold comparison circuit are used to compare the output voltage value of the integration circuit with a preset value;

[0019] The positive channel logic control circuit and the negative channel logic control circuit control the on and off of the first switch, the second switch, and the third switch according to the comparison between the output voltage value and the preset value;

[0020] The present invention uses a positive and negative channel threshold comparator to determine whether a positive constant current source or a negative constant current source is needed; by controlling the on and off of the first switch and the second switch to achieve different ways of inserting integral capacitors, the constant current source can be either positive or negative.

[0021] The present invention solves the problem of high power consumption in the current-frequency conversion circuit through a single constant current source; it also solves the problem of two adaptation references for the positive constant current source and the negative constant current source, and can better solve the problem of symmetry in the current-frequency conversion circuit; at the same time, the circuit structure is simple and the cost is low.

[0022] Furthermore, the constant current source includes a reference voltage source, a DC power supply, a first resistor, a second resistor, a third resistor, a first operational amplifier, and a MOS tube;

[0023] The first input end of the first operational amplifier is connected to the reference voltage source, the second input end of the first operational amplifier is respectively connected to the first end of the first resistor, the first end of the second resistor, and the second end of the MOS tube, the second end of the first resistor and the second end of the second resistor are both connected to the DC power supply, the output end of the first operational amplifier is connected to the first end of the third resistor, the second end of the third resistor is connected to the first end of the MOS tube, and the third end of the MOS tube is respectively connected to the first end of the first switch, the first end of the second switch, and the first end of the third switch.

[0024] Furthermore, the first resistor and the second resistor are precision resistors.

[0025] Further, the integration circuit includes a first capacitor, a second operational amplifier, a fourth resistor, a fifth resistor, and a second capacitor;

[0026] The first end of the first capacitor is connected to the second end of the first switch, the second end of the first capacitor is connected to the second end of the second switch, the first input end of the second operational amplifier is grounded, the second input end of the second operational amplifier is respectively connected to the second end of the fourth resistor and the first end of the first capacitor, the output end of the second operational amplifier is respectively connected to the second end of the first capacitor and the first end of the fifth resistor, the second end of the fifth resistor is connected to the first end of the second capacitor, the first end of the positive channel threshold comparison circuit, and the first end of the negative channel threshold comparison circuit, the second end of the second capacitor is grounded, and the first end of the fourth resistor is connected to the input current.

[0027] Based on the same inventive concept, the present invention also provides a method for implementing current-frequency conversion, including the following process:

[0028] The current is input into the integration circuit to charge the integration circuit, and the integration circuit is discharged when it is connected to the constant current source;

[0029] When the output voltage value of the integration circuit is greater than the first threshold value of the positive channel threshold comparison circuit, the first switch is opened, the second switch is closed, and the third switch is opened, so as to reversely charge the integration circuit;

[0030] When the output voltage value of the integration circuit is less than the second threshold value of the negative channel threshold comparison circuit, the first switch is closed, the second switch is opened, and the third switch is opened, so as to positively charge the integration circuit;

[0031] When the output voltage value of the integration circuit is greater than or equal to the second threshold of the negative channel threshold comparison circuit and less than or equal to the first threshold of the positive channel threshold comparison circuit, the first switch is opened, the second switch is opened, and the third switch is closed.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention uses a positive and negative channel threshold comparator to determine whether a positive constant current source or a negative constant current source is needed; by controlling the on and off of the first switch and the second switch to achieve different ways of inserting integral capacitors, the constant current source can be either positive or negative.

[0034] The present invention solves the problem of high power consumption in the current-frequency conversion circuit through a single constant current source; it also solves the problem of two adaptation references for the positive constant current source and the negative constant current source, and can better solve the problem of symmetry in the current-frequency conversion circuit; at the same time, its circuit structure is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the current-frequency conversion circuit of the present invention;

[0036] Figure 2 It is a schematic diagram of the connection between the constant current source and the integration circuit of the present invention;

[0037] Figure 3 It is a schematic diagram of a constant current source circuit of the present invention. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below in conjunction with the embodiments. It should be noted that the embodiments and features of the embodiments of the present invention can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear in the following, they only indicate that the upper, lower, left and right directions are consistent with the drawings themselves, and do not limit the structure.

[0039] Example

[0040] like Figure 1 , Figure 2 The current-frequency conversion circuit of this embodiment includes a positive channel threshold comparison circuit, a negative channel threshold comparison circuit, a positive channel logic control circuit, a negative channel logic control circuit, an integration circuit, a constant current source, a first switch K1, a second switch K2, and a third switch K3.

[0041] The constant current source provides a positive constant current source or a negative constant current source for the integration circuit through the first switch K1 and the second switch K2.

[0042] The positive channel threshold comparison circuit and the positive channel threshold comparison circuit are used to compare the output voltage value of the integration circuit with a preset value.

[0043] The positive channel logic control circuit and the negative channel logic control circuit control the on and off of the first switch K1 , the second switch K2 , and the third switch K3 according to the comparison between the output voltage value and the preset value.

[0044] The output end of the constant current source is connected to the first end of the first switch K1 , the first end of the second switch K2 , and the first end of the third switch K3 , respectively; and the second end of the third switch K3 is grounded.

[0045] The second end of the first switch K1 is connected to the first end of the integration circuit, and the second end of the second switch K2 is connected to the second end of the integration circuit.

[0046] The third terminal of the integration circuit is connected to the first terminal of the positive channel threshold comparison circuit and the first terminal of the negative channel threshold comparison circuit respectively. The third terminal of the integration circuit outputs a voltage value.

[0047] The second end of the positive channel threshold comparison circuit is connected to the positive channel logic control circuit; the second end of the negative channel threshold comparison circuit is connected to the negative channel logic control circuit.

[0048] like Figure 3 The constant current source includes a reference voltage source, a DC power supply, a first resistor R1, a second resistor R2, a third resistor R3, a first operational amplifier Y1, and a MOS tube V1.

[0049] The first input terminal (non-inverting input terminal) of the first operational amplifier Y1 is connected to a reference voltage source, the second input terminal (inverting input terminal) of the first operational amplifier Y1 is respectively connected to the first end of the first resistor R1, the first end of the second resistor R2, and the second end (S-level) of the MOS tube V1, the second end of the first resistor R1 and the second end of the second resistor R2 are both connected to a DC power supply, the output terminal of the first operational amplifier Y1 is connected to the first end of the third resistor R3, the second end of the third resistor R3 is connected to the first end (G-level) of the MOS tube V1, and the third end (D-level) of the MOS tube V1 is respectively connected to the first end of the first switch K1, the first end of the second switch K2, and the first end of the third switch K3.

[0050] The first resistor R1 and the second resistor R2 are precision resistors; the reference voltage source provides a high-precision voltage reference source.

[0051] As the quantizer of pulses in the current-frequency conversion circuit, Hengli Source uses a high-precision reference voltage source and high-precision resistors to provide protection for the circuit.

[0052] The integration circuit is used to integrate the input current, such as Figure 3The integration circuit includes a first capacitor C1, a second operational amplifier Y2, a fourth resistor R4, a fifth resistor R5, and a second capacitor C2.

[0053] The first end of the first capacitor C1 (the first end of the integration circuit) is connected to the second end of the first switch K1, the second end of the first capacitor C1 (the second end of the integration circuit) is connected to the second end of the second switch K2, the first input end (the non-inverting input end) of the second operational amplifier Y2 is grounded, the second input end (the inverting input end) of the second operational amplifier Y2 is respectively connected to the second end of the fourth resistor R4 and the first end of the first capacitor C1, the output end of the second operational amplifier Y2 is respectively connected to the second end of the first capacitor C1 and the first end of the fifth resistor R5, the second end of the fifth resistor R5 (the third end of the integration circuit) is connected to the first end of the second capacitor C2, the first end of the positive channel threshold comparison circuit, and the first end of the negative channel threshold comparison circuit, the second end of the second capacitor C2 is grounded, and the first end of the fourth resistor R4 is connected to the input current.

[0054] Whether a positive constant current source or a negative constant current source is needed is determined by the positive channel threshold comparator and the negative channel threshold comparator; by controlling the on and off of the first switch K1 and the first switch K2 to achieve different ways of inserting integral capacitors, the positive constant current source can be either positive or negative.

[0055] The current is input into the integration circuit to charge the integration circuit, and the integration circuit is discharged when it is connected to the constant current source;

[0056] When the output voltage value of the integration circuit is greater than the first threshold value of the positive channel threshold comparison circuit, a negative constant current source is required, the first switch K1 is disconnected, the second switch K2 is closed, and the third switch K3 is disconnected, so as to reversely charge the integration circuit;

[0057] When the output voltage value of the integration circuit is less than the second threshold value of the negative channel threshold comparison circuit, a positive constant current source is required, the first switch K1 is closed, the second switch K2 is opened, and the third switch K3 is opened to charge the integration circuit in a positive direction;

[0058] When the output voltage value of the integration circuit is greater than or equal to the second threshold value of the negative channel threshold comparison circuit, and less than or equal to the first threshold value of the positive channel threshold comparison circuit, a constant current source is not required, the first switch K1 is disconnected, the second switch K2 is disconnected, and the third switch K3 is closed, and the constant current source flows into the bypass to the ground through the third switch K3.

[0059] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

Claims

1. A current-frequency conversion circuit, comprising a positive channel threshold comparison circuit, a negative channel threshold comparison circuit, a positive channel logic control circuit, a negative channel logic control circuit, and an integration circuit, characterized in that: It also includes a constant current source, a first switch (K1), a second switch (K2), and a third switch (K3); The output end of the constant current source is respectively connected to the first end of the first switch (K1), the first end of the second switch (K2), and the first end of the third switch (K3); A second end of the third switch (K3) is grounded; The second end of the first switch (K1) is connected to the first end of the integration circuit, and the second end of the second switch (K2) is connected to the second end of the integration circuit; The third terminal of the integration circuit is connected to the first terminal of the positive channel threshold comparison circuit and the first terminal of the negative channel threshold comparison circuit respectively; The second end of the positive channel threshold comparison circuit is connected to the positive channel logic control circuit; The second end of the negative channel threshold comparison circuit is connected to the negative channel logic control circuit; The constant current source provides a positive constant current source or a negative constant current source for the integration circuit through the first switch (K1) and the second switch (K2); The positive channel threshold comparison circuit and the negative channel threshold comparison circuit are used to compare the output voltage value of the integration circuit with a preset value; The positive channel logic control circuit and the negative channel logic control circuit control the on and off of the first switch (K1), the second switch (K2) and the third switch (K3) according to the comparison between the output voltage value and the preset value.

2. The current-frequency conversion circuit according to claim 1, characterized in that: The constant current source comprises a reference voltage source, a direct current power supply, a first resistor (R1), a second resistor (R2), a third resistor (R3), a first operational amplifier (Y1), and a MOS tube (V1); The first input end of the first operational amplifier (Y1) is connected to the reference voltage source, the second input end of the first operational amplifier (Y1) is respectively connected to the first end of the first resistor (R1), the first end of the second resistor (R2), and the second end of the MOS tube (V1), the second end of the first resistor (R1) and the second end of the second resistor (R2) are both connected to the DC power supply, the output end of the first operational amplifier (Y1) is connected to the first end of the third resistor (R3), the second end of the third resistor (R3) is connected to the first end of the MOS tube (V1), and the third end of the MOS tube (V1) is respectively connected to the first end of the first switch (K1), the first end of the second switch (K2), and the first end of the third switch (K3).

3. The current-frequency conversion circuit according to claim 2, characterized in that: The first resistor (R1) and the second resistor (R2) are precision resistors.

4. The current-frequency conversion circuit according to claim 1, characterized in that: The integration circuit comprises a first capacitor (C1), a second operational amplifier (Y2), a fourth resistor (R4), a fifth resistor (R5), and a second capacitor (C2); The first end of the first capacitor (C1) is connected to the second end of the first switch (K1), the second end of the first capacitor (C1) is connected to the second end of the second switch (K2), the first input end of the second operational amplifier (Y2) is grounded, the second input end of the second operational amplifier (Y2) is respectively connected to the second end of the fourth resistor (R4) and the first end of the first capacitor (C1), the output end of the second operational amplifier (Y2) is respectively connected to the second end of the first capacitor (C1) and the first end of the fifth resistor (R5), the second end of the fifth resistor (R5) is respectively connected to the first end of the second capacitor (C2), the first end of the positive channel threshold comparison circuit, and the first end of the negative channel threshold comparison circuit, the second end of the second capacitor (C2) is grounded, and the first end of the fourth resistor (R4) is connected to the input current.

5. A method for implementing current frequency conversion, characterized in that: The current-frequency conversion circuit according to any one of claims 1 to 4 is implemented, comprising the following process: The current is input into the integration circuit to charge the integration circuit, and the integration circuit is discharged when it is connected to the constant current source; When the output voltage value of the integration circuit is greater than the first threshold value of the positive channel threshold comparison circuit, the first switch (K1) is disconnected, the second switch (K2) is closed, and the third switch (K3) is disconnected, so as to reversely charge the integration circuit; When the output voltage value of the integration circuit is less than the second threshold value of the negative channel threshold comparison circuit, the first switch (K1) is closed, the second switch (K2) is opened, and the third switch (K3) is opened, so that the integration circuit is positively charged; When the output voltage value of the integration circuit is greater than or equal to the second threshold value of the negative channel threshold comparison circuit and less than or equal to the first threshold value of the positive channel threshold comparison circuit, the first switch (K1) is opened, the second switch (K2) is opened, and the third switch (K3) is closed.

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