Voltage frequency conversion hybrid integrated circuit
阅读说明：本技术 电压频率转换混合集成电路 (Voltage frequency conversion hybrid integrated circuit ) 是由 李建和 王泉 房建峰 王健 祝节 魏刚剑 于 2020-08-11 设计创作，主要内容包括：本发明公开了一种电压频率转换混合集成电路,包括积分电路；积分电路采用以电压基准器为基础的正、负电源来供电；积分电路中包括运算放大器,两个串联在运算放大器反相输入端的输入电阻,两个输入电阻的阻值不同、温度系数大小不同且符号相反。本发明的电路,零偏小,零偏漂移小,稳定性好,线性度好；零偏自动校准,无需外围调节和软件补偿,结构简单,成本低；体积小,通用性强。(The invention discloses a voltage frequency conversion hybrid integrated circuit, which comprises an integrating circuit; the integrating circuit is powered by a positive power supply and a negative power supply based on a voltage reference device; the integrating circuit comprises an operational amplifier and two input resistors which are connected in series at the inverting input end of the operational amplifier, wherein the two input resistors have different resistance values and different temperature coefficients and have opposite signs. The circuit of the invention has small zero offset, small zero offset drift, good stability and good linearity; zero-offset automatic calibration is realized, peripheral adjustment and software compensation are not needed, the structure is simple, and the cost is low; small volume and strong universality.)
1. A voltage frequency conversion hybrid integrated circuit is characterized by comprising an integrating circuit; the integrating circuit is powered by a positive power supply and a negative power supply based on a voltage reference device;
the integrating circuit comprises an operational amplifier and two input resistors which are connected in series at the inverting input end of the operational amplifier, wherein the two input resistors have different resistance values and different temperature coefficients and have opposite signs.
2. The voltage-to-frequency conversion hybrid integrated circuit of claim 1, wherein the input voltage of the voltage reference is 15V to 40V, the output voltage is +5V, and the positive power supply is directly supplied to the integrating circuit; the output end of the voltage reference device is connected with the inverting amplifier, and the +5V voltage output by the voltage reference device is converted into-5V voltage after passing through the inverting amplifier, and the-5V voltage is provided for the negative power supply of the integrating circuit.
3. The voltage-to-frequency conversion hybrid integrated circuit of claim 1, wherein the operational amplifier is selected from the group consisting of operational amplifiers with offset voltage less than 10 μ ν, offset current less than 100pA, and bias current less than 100 pA.
4. The voltage-to-frequency conversion hybrid integrated circuit of claim 1, wherein the operational amplifier is an operational amplifier with bias auto-calibration function.
5. The voltage-to-frequency conversion hybrid integrated circuit of claim 1, further comprising a comparator circuit, a flip-flop circuit, an analog switch circuit, and a constant current source circuit; the input signal voltage VIN is input into the integrating circuit, the output signal of the integrating circuit is output to the trigger circuit through the comparator circuit, and one of the two paths of signals FO + and FO-is output through the trigger circuit.
6. The voltage-to-frequency conversion hybrid integrated circuit of claim 5, wherein the flip-flop circuit outputs the FO + signal and the FO-no output when the input signal voltage VIN is greater than 0V;
when the input signal voltage VIN is less than 0V, the trigger circuit outputs FO-signal and FO + has no output;
when the input signal voltage VIN is equal to 0V, the flip-flop circuit outputs either the FO + signal or the FO-signal, which has one and only one output.
Technical Field
The invention relates to a voltage-frequency conversion hybrid integrated circuit, in particular to a high-stability voltage-frequency conversion hybrid integrated circuit with dual-channel output.
Background
The voltage-frequency conversion circuit converts an input analog voltage signal into a counting pulse and outputs the counting pulse, wherein the frequency of the counting pulse is proportional to the amplitude value of the input voltage signal. The method has the characteristics of strong anti-interference performance, high conversion resolution, high precision and the like, and is widely applied to the fields of navigation, radar, remote control and remote measurement, analog signal transmission, data acquisition and communication systems, modern navigation systems and the like.
Patent No. CN202853621U discloses an I/F conversion circuit, as shown in fig. 1, which includes an integrator, a comparator, a digital logic circuit and an electronic switch, wherein an output terminal of the integrator is connected to an input terminal of the comparator, an output terminal of the comparator is connected to an input terminal of the digital logic circuit, an output terminal of the digital logic circuit is connected to an output circuit, and an output terminal of the digital logic circuit is connected to an input terminal of the integrator through the electronic switch to form a closed loop.
The schematic diagram of the integrating circuit of the I/F conversion circuit is shown in fig. 2, an operational amplifier U1 is powered by a common power supply, and the same-phase end of the operational amplifier is connected to a ground resistor R2, so that the structural stability is poor, the zero offset drift of the circuit is large, the zero offset repeatability is poor, the zero offset of the circuit is unstable, the stability and linearity of the output frequency of the circuit are poor, and the high-precision voltage frequency conversion is difficult to realize.
Patent nos. CN102589545A and CN102589545B disclose a zero-position self-calibration voltage-frequency conversion device for an inertial measurement unit, which controls the switches to be opened and closed differently in different sampling periods through a sampling module embedded in a navigation computer, so that three independent sampling channels respectively perform zero-position self-calibration of the respective channels in sequence under the coordination of a common sampling channel. The device needs to control the continuous switching of a multi-channel electronic switch and the continuous sampling and software compensation of a computer, and has the advantages of complex structure, complex control program, poor real-time performance and high price.
With the progress of microelectronic technology, the stability of high-precision voltage-frequency conversion circuits is required to be higher and higher for electronic devices, particularly weaponry. The integrating circuit is a core part of the high-precision voltage-frequency conversion circuit, has high requirements on the stability of a power supply and an input resistor, and needs to be precisely designed. It is very important to design a voltage-frequency conversion hybrid integrated circuit with small zero offset, good stability, high precision, simple structure and low price.
Disclosure of Invention
The invention aims to provide a high-stability voltage-frequency conversion hybrid integrated circuit which has small zero bias, does not need external regulation and calibration, has high precision and simple structure.
The technical solution for realizing the purpose of the invention is as follows:
a voltage-to-frequency conversion hybrid integrated circuit includes an integrating circuit; the integrating circuit is powered by a positive power supply and a negative power supply based on a voltage reference device;
the integrating circuit comprises an operational amplifier and two input resistors which are connected in series at the inverting input end of the operational amplifier, wherein the two input resistors have different resistance values and different temperature coefficients and have opposite signs.
Furthermore, the input voltage of the voltage reference device is 15V-40V, the output voltage is +5V, and the voltage is directly supplied to a positive power supply of the integrating circuit; the output end of the voltage reference device is connected with the inverting amplifier, and the +5V voltage output by the voltage reference device is converted into-5V voltage after passing through the inverting amplifier, and the-5V voltage is provided for the negative power supply of the integrating circuit.
Furthermore, the operational amplifier is selected from the operational amplifiers with offset voltage less than 10 muV, offset current less than 100pA and bias current less than 100 pA.
Further, the operational amplifier is an operational amplifier with an automatic bias calibration function.
Furthermore, the device also comprises a comparator circuit, a trigger circuit, an analog switch circuit and a constant current source circuit; the input signal voltage VIN is input into the integrating circuit, the output signal of the integrating circuit is output to the trigger circuit through the comparator circuit, and one of the two paths of signals FO + and FO-is output through the trigger circuit.
Further, when the input signal voltage VIN is greater than 0V, the flip-flop circuit outputs an FO + signal and FO-has no output;
when the input signal voltage VIN is less than 0V, the trigger circuit outputs FO-signal and FO + has no output;
when the input signal voltage VIN is equal to 0V, the flip-flop circuit outputs either the FO + signal or the FO-signal, which has one and only one output.
Compared with the prior art, the invention has the following remarkable advantages:
the device has small zero offset, small zero offset drift, good stability and good linearity;
the zero offset of the capsule wall is automatically calibrated, peripheral adjustment and software compensation are not needed, the structure is simple, and the cost is low;
⒊ is small in size and strong in universality.
Drawings
Fig. 1 is a schematic block diagram of an I/F conversion circuit of the prior art.
Fig. 2 is a schematic diagram of an integration circuit of an I/F conversion circuit of the prior art.
Fig. 3 is a schematic block diagram of a high-stability dual-channel output voltage frequency conversion hybrid integrated circuit of the present invention.
Fig. 4 is a schematic diagram of a high stability dual channel output voltage frequency conversion hybrid integrated circuit integrator circuit of the present invention.
Fig. 5 is a schematic diagram of the positive and negative power supply of the high-stability dual-channel output voltage frequency conversion hybrid integrated circuit integrating circuit of the invention.
Detailed Description
The high-stability dual-channel output voltage frequency conversion hybrid integrated circuit of the invention is a schematic block diagram, as shown in fig. 3, and comprises an integrating circuit 1, a
The core technical solution of the invention is that the integrating circuit 1 adopts a voltage stabilizing circuit based on a voltage reference device to supply power, and the voltage stabilizing circuit provides a very stable +/-5V voltage and obviously reduces the zero offset variation caused by the fluctuation of the power voltage. The integration circuit 1 adopts a specially selected precise operational amplifier which has the characteristics of low offset voltage, low offset current and low bias current, and also has the function of bias automatic calibration without external regulation and calibration. The input resistor in the integrating circuit 1 is formed by connecting two resistors R1 and R2 in series, and the two resistors have different resistance values, different temperature coefficients and opposite signs.
The invention also comprises a
The principle of the invention is as follows: the integrating circuit adopts a positive power supply and a negative power supply which are formed on the basis of a voltage reference device, the input voltage of the voltage reference device is 15V-40V, the output voltage is +5V, and the positive power supply is directly supplied to the integrating circuit; the output end of the voltage reference device is connected with the inverting amplifier, and the +5V voltage is inverted to become-5V voltage and the-5V voltage is supplied to a negative power supply of the integrating circuit. The integration circuit adopts a specially selected precise operational amplifier, the offset voltage of the operational amplifier is less than 10 muV, the offset current of the operational amplifier is less than 100pA, the bias current of the operational amplifier is less than 100pA, the operational amplifier has the function of bias automatic calibration, the offset voltage, the offset current and the bias current are kept unchanged in the full temperature range, and the stability of zero bias of the voltage-frequency conversion circuit is ensured.
An input resistor of the integrating circuit is formed by connecting two resistors R1 and R2 in series, the temperature coefficient of the resistor is firstly determined, if the resistor R1 adopts a resistor with the temperature coefficient of 300 ppm/DEG C, the resistor R2 adopts a resistor with the temperature coefficient of-30 ppm/DEG C, and then the resistance value of the resistor is determined, if the resistor R1 adopts 2k omega and the resistor R2 adopts 20k omega, when the working temperature changes, the resistance values of the two resistors both change by 0.6 omega/DEG C, but because the signs of the temperature coefficients of the two resistors are opposite, the total resistance value of the two resistors keeps unchanged, and the constancy of the input current is ensured. The invention also comprises a general comparator circuit, a trigger circuit, an analog switch circuit and a constant current source circuit, and the general comparator circuit, the trigger circuit, the analog switch circuit and the constant current source circuit form a high-stability voltage-frequency conversion hybrid integrated circuit together with the integrating circuit to finish the voltage-frequency conversion.
Referring to fig. 4, a schematic diagram of the integrated circuit of the high-stability dual-channel output voltage frequency conversion hybrid integrated circuit of the present invention is shown. In the integrating circuit, one end of a resistor R1 is used as an input signal voltage VIN, the other end of the resistor R1 is connected with a resistor R2 in series, and the other end of the resistor R2 is connected with the inverting input end of an operational amplifier N1; the non-inverting input terminal of the operational amplifier N1 is grounded; one end of the capacitor C1 is connected with the inverting input end of the operational amplifier N1; the other end is connected with the output end VOUT of the operational amplifier N1; the positive power supply end V + of the operational amplifier N1 is connected with the positive power supply circuit (I); the negative power supply end V-of the operational amplifier N1 is connected with a negative power supply circuit II; the inverting input of the operational amplifier N1 is also the input of the discharge current IK.
With reference to fig. 5, in the schematic diagram of the positive and negative power supply circuits of the high-stability dual-channel output voltage frequency conversion hybrid integrated circuit integrating circuit of the present invention, the power supply terminal of the second pin of the voltage reference N2 is connected to the positive power supply VCC; the fourth pin of the voltage reference N2 is grounded GND; one end of the capacitor C2 is connected with a second pin power supply end of the voltage reference N2, and the other end of the capacitor C2 is grounded GND; one end of the resistor R3 is connected with the sixth pin output end of the voltage reference N2, and the other end is connected with the inverting input end of the operational amplifier N3; one end of the capacitor C3 is connected with the sixth pin output end of the voltage reference device N2, and the other end of the capacitor C3 is grounded GND; one end of the resistor R4 is connected with the inverting input end of the operational amplifier N3, and the other end is connected with the output end of the operational amplifier N3; the non-inverting input end of the operational amplifier N3 is grounded GND; a positive power supply end of the operational amplifier N3 is connected with a positive power supply VCC, one end of the capacitor C4 is connected with a positive power supply end of the operational amplifier N3, and the other end of the capacitor C4 is grounded GND; the negative power supply of the operational amplifier N3 is connected with the negative power supply VEE, one end of the capacitor C5 is connected with the negative power supply end of the operational amplifier N3, and the other end of the capacitor C5 is grounded GND; one end of the capacitor C6 is connected with the output end of the operational amplifier N3, and the other end is grounded GND. The output voltage V + of the sixth pin output terminal of the voltage reference N2 provides the power supply voltage V + for the positive power supply terminal of the operational amplifier N1 in fig. 4; the output terminal of the operational amplifier N3 outputs a voltage V-which provides the supply voltage V-to the negative power supply terminal of the operational amplifier N1 of FIG. 4.
The high-stability dual-channel output voltage frequency conversion hybrid integrated circuit has the following electrical performance indexes:
a. input voltage: -7.5V
b. Output frequency: 0 to 200kHz
c. Zero offset: -0.5Hz
d. Zero offset drift: +/-0.2 Hz (input of 0)
e. Zero bias repeatability (3 power-ups): 0.2Hz
f. Non-linearity (root mean square difference): less than or equal to 0.06 thousandth
i. Positive and negative channel symmetry: less than or equal to 0.05 percent.
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