阅读说明：本技术 一种高频信号输出电路 (High-frequency signal output circuit ) 是由 蒋兵 郑富辉 陈斌根 于 2020-06-22 设计创作，主要内容包括：本发明涉及一种高频信号输出电路,包括级联的第一信号处理电路以及第二信号处理电路,高频方波信号PWM_IN输入所述第一信号处理电路的信号输入端,所述第一信号处理电路的输出端连接所述第二信号处理电路的输入端,所述第二信号处理电路的输出端输出调幅后稳定的高频方波信号PWM_OUT。输入的PWM_IN信号为整车控制器主芯片所发出来的PWM方波信号,由工作电源VCC作为PWM_IN信号的调幅基准,经过本发明的电路的处理后输出稳定的高频方波信号PWM_OUT作为外部设备的信号采样输入。本发明具有适合多种使用场合、宽电压且具有较强的适应性、性能可靠且输出波形稳定、成本极低且器件极易采购等特点。(The invention relates to a high-frequency signal output circuit which comprises a first signal processing circuit and a second signal processing circuit which are cascaded, wherein a high-frequency square wave signal PWM _ IN is input into a signal input end of the first signal processing circuit, an output end of the first signal processing circuit is connected with an input end of the second signal processing circuit, and an output end of the second signal processing circuit outputs a high-frequency square wave signal PWM _ OUT which is stable after amplitude modulation. The input PWM _ IN signal is a PWM square wave signal sent by a main chip of the vehicle controller, a working power supply VCC is used as an amplitude modulation reference of the PWM _ IN signal, and the stable high-frequency square wave signal PWM _ OUT is output as the signal sampling input of external equipment after the processing of the circuit. The invention is suitable for various use occasions, has wide voltage, has stronger adaptability, reliable performance, stable output waveform, extremely low cost, extremely easy purchase of devices and the like.)

1. The high-frequency signal output circuit is characterized by comprising a first signal processing circuit and a second signal processing circuit which are cascaded, wherein a high-frequency square wave signal PWM _ IN is input into a signal input end of the first signal processing circuit, an output end of the first signal processing circuit is connected with an input end of the second signal processing circuit, and an output end of the second signal processing circuit outputs a high-frequency square wave signal PWM _ OUT which is stable after amplitude modulation.

2. The high-frequency signal output circuit according to claim 1, wherein the first signal processing circuit comprises resistors R1-R3 and a first MOS transistor Q1, the high-frequency square wave signal PWM _ IN is connected to the gate of the first MOS transistor Q1 through the resistor R1, and the common node between the resistor R1 and the gate of the first MOS transistor Q1 is grounded through the resistor R2; the source electrode of the first MOS transistor Q1 is grounded, the drain electrode of the first MOS transistor Q1 is connected with a working power supply VCC through the resistor R3, and the common node of the drain electrode of the first MOS transistor Q1 and the resistor R3 is used as the output end of the first signal processing circuit.

3. The high-frequency signal output circuit according to claim 2, wherein said first MOS transistor Q1 is an NMOS transistor.

4. The high-frequency signal output circuit according to any one of claims 1-3, wherein the second signal processing circuit comprises resistors R4-R6 and a second MOS transistor Q2, the output terminal of the first signal processing circuit is connected to the gate of the second MOS transistor Q2, the source of the second MOS transistor Q2 is connected to a working power VCC through the resistor R6, the drain of the second MOS transistor Q2 is grounded through the resistor R4, and the common node between the drain of the second MOS transistor Q2 and the resistor R4 outputs the processed high-frequency square wave signal PWM _ OUT through the resistor R5.

5. The high-frequency signal output circuit according to claim 4, wherein said second MOS transistor Q2 is a PMOS transistor.

6. The high-frequency signal output circuit according to claim 5, wherein an anti-reverse diode D1 is further disposed on an end of the resistor R5 away from the second MOS transistor Q2, a negative electrode of the anti-reverse diode D1 is connected to the resistor R5, and an anode thereof is grounded.

Technical Field

The invention relates to the technical field of automobile electronic signal acquisition, processing and control, in particular to a high-frequency signal output circuit.

Background

With the rapid development of modern electronic technology, especially the requirements of electric vehicles on the performance of electronic parts of automobiles are higher and higher, and the requirements on the signal processing speed are gradually increased, so that the application of high-frequency signal processing circuits on the whole automobiles is wider and wider.

The output waveform of the automobile controller has certain technical requirements, for example, a path of high-frequency square wave signal is required to be output to other electronic equipment of the whole automobile, the highest frequency value of the required square wave needs to reach or even exceed 100KHz, and in addition, the high-frequency signal is required to have better waveform performance, the waveform duty ratio is not higher than 65%, the waveform amplitude is not higher than 1.1 times of VCC value, and the waveform output stability and signal jumping are not required to be ensured.

In view of this, firstly, circuit construction is performed based on a conventional triode device combination mode, and through actual circuit simulation and testing, it is known that a circuit constructed by adopting a triode has a barely square wave output in a low frequency band (frequency point of 100Hz and below), but waveform distortion is quite serious, and a frequency point higher than the frequency point has serious waveform distortion, and various characteristic parameters of a required waveform cannot be guaranteed. Therefore, a high frequency signal output circuit is additionally sought to ensure a good desired signal output waveform and various kinds of characteristic parameters of the waveform.

Disclosure of Invention

The invention provides a high-frequency signal output circuit aiming at the technical problems in the prior art, which has the advantages of simple structure, strong voltage adaptability, low cost, reliable performance and stable output waveform.

The technical scheme for solving the technical problems is as follows:

a high-frequency signal output circuit comprises a first signal processing circuit and a second signal processing circuit which are cascaded, wherein a high-frequency square wave signal PWM _ IN is input into a signal input end of the first signal processing circuit, an output end of the first signal processing circuit is connected with an input end of the second signal processing circuit, and an output end of the second signal processing circuit outputs a high-frequency square wave signal PWM _ OUT which is stable after amplitude modulation.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, the first signal processing circuit comprises resistors R1-R3 and a first MOS transistor Q1, the high-frequency square-wave signal PWM _ IN is connected to the gate of the first MOS transistor Q1 through the resistor R1, and a common node between the resistor R1 and the gate of the first MOS transistor Q1 is grounded through the resistor R2; the source electrode of the first MOS transistor Q1 is grounded, the drain electrode of the first MOS transistor Q1 is connected with a working power supply VCC through the resistor R3, and the common node of the drain electrode of the first MOS transistor Q1 and the resistor R3 is used as the output end of the first signal processing circuit.

Further, the first MOS transistor Q1 is an NMOS transistor.

Further, the second signal processing circuit includes resistors R4-R6 and a second MOS transistor Q2, the output end of the first signal processing circuit is connected to the gate of the second MOS transistor Q2, the source of the second MOS transistor Q2 is connected to the working power supply VCC through a resistor R6, the drain of the second MOS transistor Q2 is grounded through a resistor R4, and the drain of the second MOS transistor Q2 and the common node of the resistor R4 are connected to the resistor R5 to output the processed high-frequency square wave signal PWM _ OUT.

Further, the second MOS transistor Q2 is a PMOS transistor.

Further, an anti-reverse diode D1 is further disposed at one end of the resistor R5, which is far away from the second MOS transistor Q2, a negative electrode of the anti-reverse diode D1 is connected to the resistor R5, and an anode of the anti-reverse diode D1 is grounded.

The invention has the beneficial effects that: the method is suitable for various use occasions: the circuit board can be used in the vehicle controller, and can also be independently made into a miniature portable signal processing unit. Second, wide voltage and have stronger adaptability: the voltage value of a VCC power supply adopted by the circuit can be from +5V to +12V, the circuit has strong voltage adaptability, and the highest output undistorted frequency value can reach 2.0MHz under the state of the +5V power supply. Thirdly, reliable performance and stable output waveform: the MOS tube adopted by the circuit has good market performance in the application layer, and can ensure excellent and stable square wave signal output. Fourthly, the cost is extremely low and the devices are extremely easy to purchase: the comprehensive cost of the circuit is less than one yuan, and all the used devices are particularly easy to purchase.

Drawings

FIG. 1 is a block diagram showing the structure of a high frequency signal output circuit according to the present invention;

FIG. 2 is a schematic circuit diagram of the high frequency signal output circuit of the present invention;

FIG. 3 is a diagram of input/output signal testing of the high frequency signal output circuit according to the present invention.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

The high-frequency signal output circuit of the embodiment is mainly used in an output signal processing scene of an automobile controller, and comprises a working power supply VCC part and a fast operation signal processing circuit, wherein the working power supply VCC can adopt the output voltage of a direct current voltage stabilization chip of the power supply circuit of the automobile controller, and can also adopt the voltage of a voltage stabilization power supply outside the controller, and the range of the working power supply VCC can be + 5V- + 12V.

As shown IN fig. 1, the input PWM _ IN signal is a +5V PWM square wave signal sent by the main chip of the vehicle controller, the signal is connected to the fast operation circuit, and the PWM _ OUT square wave pulse signal output by the fast operation circuit is directly output to the sampling terminal of the external device, and is used as the signal sampling input of the external device.

The high-frequency signal output circuit of the embodiment includes a first signal processing circuit and a second signal processing circuit which are cascaded, a high-frequency square wave signal PWM _ IN is input to a signal input end of the first signal processing circuit, an output end of the first signal processing circuit is connected to an input end of the second signal processing circuit, and an output end of the second signal processing circuit outputs a high-frequency square wave signal PWM _ OUT which is stable after amplitude modulation.

Specifically, as shown in the schematic circuit diagram of fig. 2, the first signal processing circuit includes resistors R1 to R3 and a first MOS transistor Q1, and the first MOS transistor Q1 is an NMOS transistor. The high-frequency square wave signal PWM _ IN sent by the main chip of the vehicle controller is connected to the grid electrode of the first MOS tube Q1 through a resistor R1, and the common node of the resistor R1 and the grid electrode of the first MOS tube Q1 is grounded through a resistor R2. The source electrode of the first MOS transistor Q1 is grounded, the drain electrode of the first MOS transistor Q1 is connected with a working power supply VCC through a resistor R3, and the common node of the drain electrode of the first MOS transistor Q1 and the resistor R3 is used as the output end of the first signal processing circuit.

Furthermore, the second signal processing circuit comprises resistors R4-R6 and a second MOS transistor Q2, and the second MOS transistor Q2 adopts a PMOS transistor. The output end of the first signal processing circuit is connected to the grid of a second MOS tube Q2, the source electrode of the second MOS tube Q2 is connected with a working power supply VCC through a resistor R6, the drain electrode of the second MOS tube Q2 is grounded through a resistor R4, and the common node of the drain electrode of the second MOS tube Q2 and a resistor R4 outputs a processed high-frequency square wave signal PWM _ OUT through a resistor R5.

Further, an anti-reverse diode D1 is further disposed at the output end of the second signal processing circuit, i.e., at the end of the resistor R5 away from the second MOS transistor Q2, a negative electrode of the anti-reverse diode D1 is connected to the resistor R5, and an anode thereof is grounded.

The first signal processing circuit and the second signal processing circuit in the circuit shown in fig. 2 are the core of the present invention, the design needs to consider the respective basic performance parameters of the two types of MOS transistors, especially the parameters of peripheral devices, and directly determines the waveform frequency, amplitude and duty ratio of signal output, and in addition, the implementation of the hardware circuit, i.e. the type selection and wiring mode of components and devices, directly determines the cost and performance of the circuit.

In this embodiment, a signal output port of the main chip of the vehicle controller outputs a +5V square wave signal with a duty ratio of 50%, and the signal is processed by a fast arithmetic processing circuit constructed by the first MOS transistor Q1 and the second MOS transistor Q2 to output a high-frequency square wave signal that meets the expectation and is required by the rear-end device.

The square wave signal PWM _ IN output by the main chip port of the controller is sent to the grid electrode of the first MOS tube Q1 through the resistor R1, the resistor R1 and the resistor R2 form a voltage division circuit at the same time, and primary voltage division clamping is carried out on the amplitude of the input square wave signal PWM _ IN so as to ensure the stability of the PWM _ IN signal. After checking the Vgs, Igss, Idss and other parameter values of the first MOS transistor Q1, and through calculation and verification, the resistance value of the resistor R1 is selected to be 1 Komega, and the resistance value of the resistor R2 is selected to be 10 Komega. In order to ensure the drain current of the first MOS transistor Q1, the resistance value of the resistor R3 is determined to be 10K Ω by combining the working power VCC voltage value provided by the power circuit chip of the vehicle controller and the past experience, and is feasible through actual measurement. The model of the first MOS transistor Q1 is finally selected by comprehensively combining the value ranges of various technical parameters of the first MOS transistor Q1, such as the turn-on delay time td (on), the turn-off delay time td (off), the rated voltage Vdss, the on-resistance rds (on), and the like. The part of the circuit is mainly considered as follows: 1. the drain current value of the first MOS transistor Q1, in particular, the value of the resistor R3; 2. the values of the resistor R1 and the resistor R2. The values and functions of the resistor R1 and the resistor R2 are very important to select, and particularly, the resistor R1 plays a role in both current limiting and voltage dividing.

The common node of the resistor R3 and the drain of the first MOS transistor Q1 is connected to the gate of the second MOS transistor Q2, and the signal output of the first MOS transistor Q1 is used as the signal input of the second MOS transistor Q2. In consideration of factors such as the frequency characteristic of a high-speed signal and signal loss, a resistor is not connected in series between the drain of the first MOS transistor Q1 and the gate connection path of the second MOS transistor Q2.

After the signal flows into the gate of the second MOS transistor Q2, the on/off of the second MOS transistor Q2 is controlled by the continuous state change of the high/low level of the input signal. The source of the second MOS transistor Q2 is connected to the VCC voltage through a resistor R6. Considering signal loss and the fluctuation condition of conversion energy, the resistance value of the resistor R6 is set to be 0 omega, and the impedance micro characteristic of the 0 omega resistor is utilized to carry out secondary processing on noise waves on the working power supply VCC, thereby ensuring the stability of the current injected into the source electrode of the second MOS transistor Q2. The square wave output by the second MOS transistor Q2 is output to an external sampling device via a resistor R5. Meanwhile, the drain of the second MOS transistor Q2 is connected to ground through a resistor R4, and this resistor R4 plays a role in raising the voltage value of the output signal voltage in the circuit, and at the same time, guarantees the integrity of the second signal processing circuit. Comprehensively considering various characteristics of the second signal processing circuit, carrying out actual measurement, finally selecting the resistor R4 with the resistance value of 10K omega and the resistor R5 with the resistance value of 1K omega, and finally determining the model of the second MOS transistor Q2. In order to further ensure the signal external undistorted characteristic of the circuit, a reverse biased diode D1 is added between the signal external output end of the resistor R5 and the ground, the signal output end of the resistor R5 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to the ground. The diode D1 has the function of stabilizing the waveform of the high-frequency output circuit, and can stabilize the voltage value of the square wave output by the circuit on the optimal peak-to-peak voltage Vpp, and can prevent the voltage impact and damage to the circuit caused by the connection fault of an external sampling end.

Fig. 3 shows a waveform diagram of an input/output signal test of the high-frequency signal output circuit according to the present invention. The CH1 channel (upper waveform diagram) is a square wave signal PWM _ IN input into the high-frequency signal circuit, and the attenuation multiplying power of the probe is set to be X10; the CH2 channel (lower waveform diagram) is the output square wave signal PWM _ OUT of the present high frequency signal circuit, and the probe attenuation factor is set to X10. The test conditions were set as: 100kHz of square wave signal frequency f input by PWM _ IN, 50% of duty ratio, Vpp: +5V, offset: 0VVDC, phase: 0.0 degree; actually measured, the frequency f of the output square wave PWM _ OUT processed by the circuit is as follows: 100.02kHz, duty cycle of 58.55%, Vpp: +5.25V, each technical index meets expectations, and satisfies main all kinds of technical conditions.

The design strategy of the high-frequency signal output circuit of the invention is as follows: the technical index characteristics of an N-type MOS transistor (a first MOS transistor Q1) and a P-type MOS transistor (a second MOS transistor Q2) are utilized, past experience and corresponding circuit simulation are combined, and stable output of high-frequency square wave signals is finally achieved through specific type selection and value selection of various devices, so that the universality and the practicability of the circuit are further achieved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.