A power supply based on ultra-short wave direction finder tester

Abstract

The present invention discloses a power supply based on an ultra-short wave direction finder tester, specifically an isolated switching power supply, which comprises a power input terminal Vin and an output terminal Vout, wherein the output terminal Vout is connected to the input terminal of a feedback circuit, the feedback circuit is connected to the input terminal of an optocoupler isolation circuit, one output terminal of the optocoupler isolation circuit is connected to an optocoupler current regulating module and a driving circuit module, and the other end is connected to a ground terminal, and the driving circuit module generates a driving signal according to a feedback signal at the output terminal of the optocoupler circuit to control the output of the power supply circuit of the ultra-short wave direction finder tester. The present invention provides an environment detection module, a threshold setting module, and a mode judgment module, so that accurate optocoupler output current compensation runs through the entire working cycle, thereby improving the robustness and adaptability of the power supply of the ultra-short wave direction finder tester in a non-ideal environment.

Description

Technical Field

[0001] The invention relates to the field of switching power supplies, and in particular to a power supply based on an ultrashort wave direction finder tester. Background Art

[0002] The ultra-short wave direction finder is a navigation device that uses radio technology for automatic orientation, and uses radio waves to continuously measure the direction of the radio station. In the process of daily maintenance and repair troubleshooting, the ultra-short wave direction finder tester is urgently needed to provide radio direction signals to assist in the completion of maintenance and system troubleshooting, and improve the efficiency of field maintenance and guarantee. The ultra-short wave direction finder tester is usually powered by an isolated switching power supply circuit. In the isolated switching power supply, in order to ensure the stability of the output voltage, an optocoupler feedback circuit is generally used for feedback regulation. In the prior art, the optocoupler isolation feedback circuit composed of an adjustable voltage regulator and an optocoupler isolation device is widely used due to its simple structure and low cost. The output current of the above-mentioned optocoupler isolation feedback circuit increases with the decrease of output power. Therefore, when the ultra-short wave direction finder tester is in light load or standby state, the optocoupler output is large. When the output power of the ultra-short wave direction finder tester reaches the minimum, the optocoupler output current reaches the maximum, which will cause the ultra-short wave direction finder tester to produce greater power loss when it is in light load or standby state.

[0003] In the prior art, in order to reduce the power loss of the tester in the standby state, two methods are usually used, one is to change the connection resistance of the optocoupler output circuit, and the other is to set a corresponding compensation circuit to output a compensation current to reduce the optocoupler output current. The above solutions are all power loss reduction of the switching power supply in a single standby mode and at an ideal ambient temperature. However, in actual applications, the tester has multiple working modes, and the working environment of the power supply of the tester varies greatly. How to carry out accurate current compensation throughout the entire working cycle and improve its robustness and adaptability in non-ideal environments to meet the requirements of the use of ultra-short wave directivity testers in multi-mode and multi-environment is a technical problem that needs to be solved in the prior art. Summary of the invention

[0004] The present invention proposes a power supply based on an ultra-short wave direction finder tester to solve the technical problem in the prior art that the ultra-short wave direction finder tester cannot accurately reduce power loss under different operating temperatures and / or operating modes.

[0005] In order to solve the above technical problems, the present invention provides a power supply based on an ultrashort wave direction finder tester, and the specific technical scheme is as follows: a power supply based on an ultrashort wave direction finder tester, wherein the power supply circuit of the ultrashort wave direction finder tester is an isolated switching power supply, which comprises a power input terminal Vin and an output terminal Vout, wherein the output terminal Vout is connected to the input terminal of a feedback circuit, and the feedback circuit is connected to the input terminal of an optocoupler isolation circuit, wherein one output terminal of the optocoupler isolation circuit is connected to an optocoupler current regulation module and a drive circuit module, and the other end is connected to a ground terminal, and the drive circuit module generates a drive signal according to a feedback signal at the output terminal of the optocoupler circuit to control the output of the power supply circuit of the ultrashort wave direction finder tester;

[0006] The optocoupler current regulation module includes: a sampling module, whose input end is connected to the output side of the optocoupler isolation circuit; an adding circuit, which adds the output current collected by the sampling module and the compensation current of the current compensation module, and inputs the sum to the mode judgment module; an environment detection module, which detects the working environment of the optocoupler isolation circuit; a threshold setting module, wherein the output end of the environment detection module is connected to the threshold setting module, and the threshold setting module sets the corresponding threshold output function according to the working mode of the tester power supply based on the temperature characteristics of the optocoupler isolation circuit. The other input end of the mode judgment module is connected to the threshold setting module, and the threshold setting module distributes the adjusted thresholds of each mode to the mode judgment module, and the mode judgment module performs mode judgment based on the adjusted thresholds. The output end of the mode judgment module is respectively connected to the control end of the switch module and the current compensation module; the input end of the switch module is connected to the output end of the optocoupler isolation feedback circuit, and the output end of the switch module is connected to the input of the current compensation module, so as to control whether to perform current compensation by controlling the on or off of the switch module; the other end of the current compensation module is connected to the input end of the addition circuit, so as to perform current compensation on the output end of the optocoupler circuit according to different working modes of the tester, and the optocoupler current regulation module also includes a small current compensation module, and the small current compensation module is used to accurately compensate the optocoupler output current after compensation by the current compensation module, and the output end of the optocoupler isolation feedback circuit is also connected to an external power supply through a resistor Rs to power the optocoupler isolation circuit.

[0007] Furthermore, the working state of the ultrashort wave direction finder tester includes at least a normal mode, a light load mode, an ultra-light load mode and a standby mode;

[0008] The threshold setting module sets and allocates a first threshold, a second threshold and a third threshold to a mode judgment module; when the output current of the collected optocoupler isolation circuit is less than the first threshold, the mode judgment module judges that the ultrashort wave direction finder tester is operating in normal mode, at which time the control switch module is kept in an off state, the current compensation module does not perform current compensation, and the input current of the mode judgment module is equal to the output sampling current; when the sum of the output current and the compensation current is greater than the first threshold and less than the second threshold, it is judged that the tester enters a light load mode, at which time the switch module is turned on, and the current compensation module is controlled to output a first compensation current; when the sum of the output current and the compensation current is greater than the second threshold and less than the third threshold, it is judged that the tester enters an ultra-light load mode, the switch module is continuously turned on, and the current compensation module is controlled to output a second compensation current; when the sum of the output current and the compensation current is greater than the third threshold, it is judged that the tester enters a standby mode, the switch module is continuously turned on, and the current compensation module is controlled to output a third compensation current, wherein the third compensation current>the second compensation current>the first compensation current.

[0009] Furthermore, the sampling module is a current sensor, and the environment detection module is a temperature sensor.

[0010] Furthermore, the small current compensation module includes a current sampling module, a control module, a forward current compensation module and a reverse current compensation module. The current sampling module collects the optocoupler output current, and the control module selects the start and stop of the forward current compensation and / or reverse current compensation by judging the size of the optocoupler output current.

[0011] Furthermore, the threshold function in the threshold setting module is VN=W(T)*Vn, where VN is the adjusted mode threshold, W(T) is the temperature characteristic function of the optocoupler isolation circuit, Vn is the mode threshold under ideal conditions, and N and n are both integers greater than or equal to 3, and their sizes depend on the number of working modes of the tester.

[0012] Furthermore, the temperature characteristic function of the optocoupler isolation circuit is W(T)=Af(T)+B, where A is the proportional coefficient, B is the adjustment factor, and f(T) is the current transfer ratio function of the optocoupler isolation circuit, which is related to the temperature characteristics of the optocoupler isolation circuit.

[0013] Furthermore, the mode judgment module includes multiple comparison circuits, the comparison circuits are a first comparator Com1, a second comparator Com2 to a Kth comparator ComK, wherein k is an integer greater than or equal to 3, the in-phase input terminals of the first comparator Com1 to the Kth comparator ComK are all connected to the output terminal of the adder, the inverting input terminals of the first comparator Com1 to the Kth comparator ComK are connected to a threshold setting module, and the threshold setting module adjusts and allocates thresholds for different modes.

[0014] Furthermore, the switch module is a controllable switch circuit or a controllable switch tube.

[0015] Further, the current compensation module includes a plurality of MOS tubes M0-MK, wherein k is an integer greater than or equal to 3, the sources of the plurality of MOS tubes M0, M1...MK are electrically connected to one end of the switch S, the drain of the MOS tube M0 is connected to the gate and is grounded through a bias current source, the gate of the MOS tube M1 is connected to the gate of the MOS tube M0, and its drain is connected to one end of a first compensation switch K1, and the other end of the first compensation switch K1 is connected to the output end of the compensation current, the gate of the MOS tube M2 is connected to the gate of the MOS tube M0, and its drain is connected to one end of a second compensation switch K2, and the other end of the second compensation switch K2 is connected to the output end of the compensation current, and the gate of the MOS tube M3 is connected to the MOS tube M0. The gate of the MOS tube MK is connected to the gate of the MOS tube M0, and the drain of the MOS tube MK is connected to one end of the Kth compensation switch Kk, and the other end of the Kth compensation switch Kk is connected to the output end of the compensation current; the output end of the first comparator Com1 is respectively connected to the control end of the switch S and the first compensation switch K1, the output end of the second comparator Com2 is connected to the control end of the second compensation switch K2, the output end of the third comparator Com3 is connected to the control end of the third compensation switch K3, and so on, the output end of the Kth comparator is connected to the control end of the Kth switch.

[0016] Furthermore, the small current compensation module is arranged at the connection between the first compensation switch, the second compensation switch and the third compensation switch.

[0017] Furthermore, the forward current compensation module may be a plurality of forward current compensation branches connected in parallel, and the reverse current compensation module may be a plurality of reverse current compensation branches connected in parallel, wherein the forward current compensation branch increases the total compensation current, and the reverse current compensation branch reduces the total compensation current.

[0018] Further, the forward current compensation branch may be a forward current source and a switch connected in series, and the reverse current compensation branch may be a reverse current source and a switch connected in series.

[0019] Furthermore, the absolute values ​​of the forward current source and the reverse current source are both smaller than the bias current source Ib.

[0020] Furthermore, the method by which the control module controls the forward current compensation and / or the reverse current compensation is: first, determine the working mode of the tester, and after outputting the corresponding first compensation current, second compensation current or third compensation current in the light load mode, ultra-light load mode or standby mode, respectively, wait for the delay time T, if the optocoupler output current Is is greater than 0, then close the forward current compensation branch; if the optocoupler output current is still greater than 0, then control the closed forward current compensation branch to add 1 until the detected optocoupler output current is equal to 0, and then stop adding the forward current compensation branch; after waiting for the delay time T, if the optocoupler output current is detected to be equal to 0, then close the reverse current compensation branch; if the optocoupler output current is still equal to 0, then control the closed reverse current compensation branch to add 1 until the detected optocoupler output current is greater than 0, and then stop adding the reverse current compensation branch, which indicates that the optimal compensation state has been reached.

[0021] Further, when the ultrashort wave direction finder tester is preset to have four working modes, the number of comparators in the mode judgment module is correspondingly set to 3, the number of MOS tubes in the current compensation module is set to 4, and the number of compensation switches connected thereto is set to 3.

[0022] Furthermore, the output ends of the multiple comparators are all connected to a timing circuit, and the timing circuit is used to control the corresponding compensation switch to be turned on when the sum of the optocoupler output current and the compensation current is greater than the current threshold for a period of time greater than time T, otherwise the compensation switch is controlled to be in an off state.

[0023] Furthermore, the output ends of the multiple comparators are all connected to a timing circuit, and the timing circuit is used to control the corresponding compensation switch to turn off when the sum of the optocoupler output current and the compensation current is less than the current threshold for a time greater than T, otherwise the compensation switch is controlled to maintain an on state.

[0024] An ultrashort wave direction finder tester comprises the aforementioned power supply, and also comprises a main control module and a display module, wherein the power supply is connected to the main control module and the display module to supply power to the main control module and the display module.

[0025] Beneficial effects of the present invention:

[0026] The present invention can divide the tester into multiple working modes by setting a mode judgment module and a current compensation module, and can compensate the output current of the optocoupler in different working modes;

[0027] The present invention sets an environment detection module and a threshold setting module to adjust the thresholds in each mode in real time according to different working temperatures, so that the working mode of the tester can be accurately judged at different working temperatures, thereby achieving accurate compensation in different working modes;

[0028] The present invention can avoid under-compensation or over-compensation of the optocoupler output current by configuring a small current compensation module, and control the optocoupler output current within a smaller range, thereby further reducing power loss.

[0029] Setting a timing module can further improve the accuracy of mode judgment and avoid malfunction of the compensation switch under current fluctuations, thereby further improving the accuracy of optocoupler output current compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A circuit block diagram of a power supply based on an ultrashort wave direction finder tester provided by the present invention;

[0031] Figure 2 A circuit block diagram of the optocoupler isolation feedback circuit provided by the present invention;

[0032] Figure 3 A circuit structure diagram of an embodiment of a current compensation module provided by the present invention;

[0033] Figure 4 A flowchart of the current compensation process in different modes provided by the present invention;

[0034] Figure 5 A flowchart of the small current compensation process provided by the present invention;

[0035] Figure 6 Schematic diagram of the waveform of the optocoupler output current and compensation current. DETAILED DESCRIPTION

[0036] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are only for illustration and are not intended to limit the present invention. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that these specific details do not have to be used to implement the present invention. In other examples, in order to avoid confusing the present invention, known circuits, materials or methods are not specifically described.

[0037] Throughout the specification, references to "one embodiment", "an embodiment", "an example" or "an example" mean that a particular feature, structure or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment", "in an embodiment", "an example" or "an example" that appear in various places throughout the specification do not necessarily refer to the same embodiment or example. In addition, particular features, structures or characteristics may be combined in one or more embodiments or examples in any appropriate combination and / or sub-combination. In addition, it should be understood by those of ordinary skill in the art that the drawings provided herein are for illustrative purposes and that the drawings are not necessarily drawn to scale. It should be understood that when an element is said to be "connected to" or "coupled to" another element, it may be directly connected or coupled to another element or there may be an intermediate element. In contrast, when an element is said to be "directly connected to" or "directly coupled to" another element, there is no intermediate element. The same reference numerals indicate the same element. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0038] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0039] like Figure 1 As shown, the power supply circuit of the ultra-short wave direction finder tester is an isolated switching power supply, which includes a power input terminal Vin and an output terminal Vout, the output terminal Vout is connected to the input terminal of the feedback circuit, the feedback circuit is connected to the input terminal of the optocoupler isolation circuit, one output terminal of the optocoupler isolation circuit is connected to the optocoupler current regulation module and the drive circuit module, and the other terminal is grounded. The drive circuit module generates a drive signal according to the feedback signal of the output terminal of the optocoupler circuit to control the output of the power supply circuit of the ultra-short wave direction finder tester.

[0040] Figure 2 The circuit block diagram of the optocoupler isolation feedback circuit provided by the present invention is as follows: Figure 2As shown, the optocoupler current regulation module includes: a sampling module, whose input end is connected to the output side of the optocoupler isolation circuit; an adding circuit, which adds the output current collected by the sampling module and the compensation current of the current compensation module, and inputs the sum to the mode judgment module; an environment detection module, wherein the environment detection module detects the working state or working environment of the optocoupler isolation circuit; a threshold setting module, wherein the output end of the environment detection module is connected to the threshold setting module, wherein the threshold setting module sets the corresponding threshold output function according to the working mode of the tester power supply based on the temperature characteristics of the optocoupler isolation circuit, so that the threshold setting module can adaptively adjust the threshold of each mode based on the current working temperature of the optocoupler isolation circuit; the other input end of the mode judgment module is connected to the threshold setting module. A threshold setting module, wherein the threshold setting module distributes the adjusted thresholds of each mode to the mode judgment module, and the mode judgment module performs mode judgment based on the adjusted thresholds. The output end of the mode judgment module is respectively connected to the switch module and the current compensation module; the output end of the switch module is connected to the input of the current compensation module to control whether current compensation is performed by controlling the on or off of the switch module; the other end of the current compensation module is connected to the output end of the optocoupler isolation feedback circuit and the input end of the addition circuit to perform current compensation on the output end of the optocoupler circuit according to different working modes of the tester, and the output end of the optocoupler isolation feedback circuit is also connected to an external power supply through a resistor Rs to power the optocoupler isolation circuit.

[0041] In one embodiment, the working state of the ultrashort wave direction finder tester includes at least a normal mode, a light load mode, an ultra-light load mode and a standby mode. When the output current of the collected optocoupler isolation circuit is less than a first threshold value V1, the mode judgment module judges that the ultrashort wave direction finder tester is working in the normal mode. At this time, the control switch module is kept in the disconnected state, the current compensation module does not perform current compensation, and the input current of the mode judgment module is equal to the output sampling current; when the sum of the output current and the compensation current is greater than the first threshold value V1 and less than the second threshold value V2, it is judged that the tester enters the light load mode. At this time, the switch module is turned on and the current compensation module is controlled to output the first compensation current; when the sum of the output current and the compensation current is greater than the second threshold value V2 and less than the third threshold value V3, it is judged that the tester enters the ultra-light load mode, the switch module is continuously turned on, and the current compensation module is controlled to output the second compensation current; when the sum of the output current and the compensation current is greater than the third threshold value V3, it is judged that the tester enters the standby mode, the switch module is continuously turned on, and the current compensation module is controlled to output the third compensation current, wherein the third compensation current>the second compensation current>the first compensation current. Therefore, by judging the different working states of the ultra-short wave direction finder tester to control the current compensation module to compensate the output of the optocoupler isolation circuit to different degrees, accurate compensation of the optocoupler current can be achieved, and the power loss of the ultra-short wave direction finder tester in different states can be reduced at the same time.

[0042] In actual use of the tester, the environment changes greatly, especially after working for a long time, the operating temperature of the switching power supply continues to rise, even reaching 80-90°C. Such a large temperature change will have a serious impact on the current transfer ratio of the optocoupler isolation circuit, and as the temperature rises, the current transfer ratio decreases more. The decrease in the current transfer ratio causes the sampled optocoupler output current to decrease. At this time, if the working mode judgment and current compensation are still performed according to the ideal state, it will cause the tester to work in light load or standby mode without compensation or although compensation is performed, the compensation is insufficient, which ultimately leads to a large power loss after compensation. Based on this, the present invention sets an environmental detection module and a threshold setting module to adaptively adjust the thresholds in each mode according to the change of ambient temperature, so as to achieve accurate judgment and current compensation for each mode.

[0043] Specifically, the threshold function in the threshold setting module is VN=W(T)*Vn, where VN is the adjusted mode threshold, W(T) is the temperature characteristic function of the optocoupler isolation circuit, Vn is the mode threshold under ideal conditions, and N and n are both integers greater than or equal to 3, and their sizes depend on the number of working modes of the tester.

[0044] In particular, the temperature characteristic function of the optocoupler isolation circuit is W(T)=Af(T)+B, where A is the proportional coefficient, B is the adjustment factor, and f(T) is the current transfer ratio function of the optocoupler isolation circuit, which is related to the temperature characteristics of the optocoupler isolation circuit and can be obtained by technical personnel in this field through testing.

[0045] The specific working principle is as follows:

[0046] When the tester works in an ideal temperature environment, the threshold setting module outputs the first threshold value V1, the second threshold value V2 and the third threshold value V3, and the mode judgment module judges the working mode of the tester and compensates the current according to the first threshold value V1, the second threshold value V2 and the third threshold value V3; with the increase of working time and the change of ambient temperature, the working temperature continues to rise, at this time the current transmission ratio of the optocoupler isolation circuit decreases, and the threshold setting module adjusts the thresholds of each mode according to the working temperature. The threshold setting module outputs the adjusted first threshold value V1', V1' is less than V1, when the sampling current is greater than or equal to V1', the mode judgment module judges that the tester enters the light load mode, the switch module is turned on, and the current compensation module outputs the first compensation current; similarly, the second threshold value V2 corresponding to the ultra-light load mode and the third threshold value V3 corresponding to the standby mode are adjusted to V2' and V3' respectively, and the mode judgment module judges whether the tester enters the ultra-light load or standby mode and compensates the current according to the sum of the output current and the compensation current. Its judgment and compensation process is similar to that under the ideal environment and will not be repeated. The present invention can adjust the thresholds of various modes in real time according to the change of the working temperature by setting the environment detection module and the threshold setting module, so as to accurately judge the working mode of the tester and realize the precise compensation of the current compensation module under different working temperatures and working modes.

[0047] Specifically, the sampling module may be a current sensor, and the environment detection module may be a temperature sensor. Figure 3 As shown, the mode judgment module includes a plurality of comparison devices, namely Figure 3 The first comparator Com1, the second comparator Com2...the Kth comparator ComK shown, where k is an integer greater than or equal to 3, and the number thereof is determined according to the number of working modes. The in-phase input terminals of the first comparator Com1 to the Kth comparator ComK are all connected to the output terminal of the adder, and the inverting input terminals of the first comparator Com1 to the Kth comparator ComK are connected to a threshold setting module, which adjusts and allocates thresholds for different modes.

[0048] The switch module may be any controllable switch circuit or controllable switch tube. The current compensation module includes a plurality of MOS tubes M0-MK, wherein k is an integer greater than or equal to 3. The sources of the MOS tubes M0, M1...MK are all electrically connected to one end of the switch S. The drain of the MOS tube M0 is connected to the gate and is grounded through a bias current source Ib. The gate of the MOS tube M1 is connected to the gate of the MOS tube M0, and its drain is connected to one end of the first compensation switch K1, and the other end of the first compensation switch K1 is connected to the output end of the compensation current. The gate of the MOS tube M2 is connected to the gate of the MOS tube M0, and its drain is connected to one end of the second compensation switch K2, and the other end of the second compensation switch K2 is connected to the output end of the compensation current. The gate of the MOS tube M3 is connected to the gate of the MOS tube M0, and its drain is connected to one end of the third compensation switch K3, and the other end of the third compensation switch K3 is connected to the output end of the compensation current. By analogy, the gate of the MOS tube MK is connected to the gate of the MOS tube M0, and its drain is connected to one end of the Kth compensation switch Kk, and the other end of the Kth compensation switch Kk is connected to the output end of the compensation current. The output end of the first comparator Com1 is connected to the control end of the switch S and the first compensation switch K1 respectively, the output end of the second comparator Com2 is connected to the control end of the second compensation switch K2, the output end of the third comparator Com3 is connected to the control end of the third compensation switch K3, and so on. The output end of the Kth comparator is connected to the control end of the Kth switch.

[0049] Specifically, the compensation process of the current compensation module is as follows: Figure 4 As shown:

[0050] When the ultra-short wave direction finder tester is converted from normal mode to standby mode, the optocoupler output current Is is firstly collected. When the output current is less than the first threshold value V1, that is, the ultra-short wave direction finder tester is working in normal mode, the first comparator to the Kth comparator all output low level. At this time, the switch S and the first compensation switch to the Kth compensation switch are all in the off state, and the compensation current is zero, that is, compensation of the optocoupler output current is prohibited; if the output current is greater than the first threshold value V1 and less than the second threshold value V2, that is, the ultra-short wave direction finder tester is working in light load mode, the first comparator outputs a high level, the control switch S and the first compensation switch are turned on, and the outputs of the other comparators are low level. At this time, the output Output the first compensation current; when the sum of the output current and the compensation current is greater than the second threshold value V2 and less than the third threshold value V3, that is, the ultra-short wave direction finder tester works in the ultra-light load mode, the first comparator and the second comparator output a high level, the control switch S and the first compensation switch and the second compensation switch are turned on, and the output of the other comparators is a low level, and the second compensation current is output at this time; when the sum of the output current and the compensation current is greater than the third threshold value V3, that is, the ultra-short wave direction finder tester works in the standby mode, the first comparator, the second comparator and the third comparator all output a high level, the control switch S and the first compensation switch, the second compensation switch and the third compensation switch are turned on, and the third compensation current is output at this time. When the ultra-short wave direction finder tester is preset to have four working modes, the number of comparators in the mode judgment module is correspondingly set to 3, the number of MOS tubes in the current compensation module is 4, and the number of control switches connected thereto is 3.

[0051] In the setting of the above current compensation module, the compensation current corresponds to the working mode of the tester one by one, and can only output a level of compensation current. If the compensation current is too small, there will still be a large power loss. If the compensation current is too large, it will cause energy waste to a certain extent. Based on this, the present invention further sets a small current compensation module to avoid under-compensation and over-compensation of current.

[0052] Specifically, if Figure 3As shown, a small current compensation module is provided at the connection of the first compensation switch, the second compensation switch and the third compensation switch, and the small current compensation module includes a current sampling module, a control module, a forward current compensation module and a reverse current compensation module; the forward current compensation module can be a plurality of forward current compensation branches connected in parallel, and the reverse current compensation module can be a plurality of reverse current compensation branches connected in parallel, the forward current compensation branch increases the total compensation current, and the reverse current compensation branch reduces the total compensation current. The forward current compensation branch can be a forward current source and a switch connected in series, and the reverse branch can be a reverse current source and a switch connected in series. The absolute values ​​of the forward current source and the reverse current source are both smaller than the bias current source Ib, and their absolute values ​​can be 1 / 10 to 1 / 5 of the bias current source Ib. The current sampling module collects the output current of the optocoupler, and the control module selects the forward current compensation or the reverse current compensation and the magnitude of the current compensation by judging the magnitude of the output current of the optocoupler.

[0053] The specific operation process is as follows Figure 5 As shown:

[0054] First, the working mode of the tester is judged. When the mode judgment module judges that the tester enters the light load mode, the switch S and the first compensation switch are closed, and the first compensation current is output. After the delay time T, the first compensation current is in a stable state, and the control module detects the size of the optocoupler output current through the sampling module. If the optocoupler output current Is is greater than 0, the forward current compensation branch is closed. After the forward compensation current is stable, the size of the optocoupler output current is judged again. If the optocoupler output current is still greater than 0, the closed forward current compensation branch is controlled to add 1 until the detected optocoupler output current is greater than 0. If the current is equal to 0, the forward current compensation branch is stopped, indicating that the optimal compensation state of the light load mode is reached; if the detected optocoupler output current is not greater than 0 after the first compensation switch is closed for a delay time T, that is, the optocoupler output current is equal to 0, the reverse current compensation branch is closed, and after the reverse compensation current is stable, the size of the optocoupler output current is judged again. If the optocoupler output current is still equal to 0, the closed reverse current compensation branch is controlled to add 1 until the detected optocoupler output current is greater than 0, then the reverse current compensation branch is stopped, indicating that the optimal compensation state of the light load mode is reached;

[0055] When the mode judgment module determines that the tester enters the ultra-light load mode, the switch S, the first compensation switch and the second compensation switch are closed to output the second compensation current. After the delay time T is waited, the second compensation current is in a stable state. The control module detects the size of the optocoupler output current through the sampling module. If the optocoupler output current Is is greater than 0, the forward current compensation branch is closed. After the forward compensation current is stable, the size of the optocoupler output current is judged again. If the optocoupler output current is still greater than 0, the closed forward current compensation branch is controlled to add 1 until the detected optocoupler output current is equal to 0. Then stop adding the forward current compensation branch, which indicates that the optimal compensation state of the ultra-light load mode is reached; if after the second compensation current delay time T is output, the detected optocoupler output current is not greater than 0, that is, the optocoupler output current is equal to 0, then close the reverse current compensation branch, and after the reverse compensation current is stable, judge the size of the optocoupler output current again. If the optocoupler output current is still equal to 0, control the closed reverse current compensation branch to add 1 until the detected optocoupler output current is greater than 0, then stop adding the reverse current compensation branch, which indicates that the optimal compensation state of the ultra-light load mode is reached;

[0056] When the mode judgment module determines that the tester enters the standby mode, the switch S and the first to third compensation switches are closed to output the third compensation current. After the delay time T is waited, the third compensation current is in a stable state. The control module detects the size of the optocoupler output current through the sampling module. If the optocoupler output current Is is greater than 0, the forward current compensation branch is closed. After the forward compensation current is stable, the size of the optocoupler output current is judged again. If the optocoupler output current is still greater than 0, the closed forward current compensation branch is controlled to add 1 until the detected optocoupler output current is equal to 0, then the forward current compensation branch is stopped. At this time, it indicates that the optimal compensation state of the standby mode is reached; if the detected optocoupler output current is not greater than 0 after the third compensation current delay time T is output, that is, the optocoupler output current is equal to 0, then the reverse current compensation branch is closed. After the reverse compensation current is stable, the size of the optocoupler output current is judged again. If the optocoupler output current is still equal to 0, then the closed reverse current compensation branch is controlled to add 1 until the detected optocoupler output current is greater than 0, then the reverse current compensation branch is stopped. At this time, it indicates that the optimal compensation state of the standby mode is reached.

[0057] The present invention makes the compensation of the optocoupler output current more accurate through the small current compensation module, thereby avoiding the phenomenon of under-compensation and over-compensation of the optocoupler output current.

[0058] In the actual current sampling process, due to load fluctuations or environmental factors, the sampled optocoupler output current is unstable, resulting in the current compensation module performing miscompensation. Based on this, the present invention connects a timing circuit to the output end of the comparator, and the timing circuit is used to determine that when the sum of the optocoupler output current and the compensation current is greater than the current threshold value for a time greater than time T, the corresponding compensation switch is controlled to be turned on, otherwise the compensation switch is controlled to remain in an off state.

[0059] When the ultra-short wave direction finder tester changes from standby mode to normal mode, the number of compensation switches consisting of the first compensation switch, the second compensation switch and the third compensation switch that are turned on decreases successively, that is, the compensation current of the current compensation module gradually decreases until all compensation switches and switch S are disconnected, and the ultra-short wave direction finder tester exits current compensation. Its control process is opposite to that when the above-mentioned tester is converted from normal mode to standby mode, and will not be repeated again.

[0060] Specifically, the waveforms of the compensation current and the optical coupler output current in different working modes of the ultrashort wave direction finder tester are as follows: Figure 6 As shown, when there is no small current compensation module, the working process is as follows:

[0061] At t0-t1, the ultrashort wave direction finder tester works in normal mode, the optocoupler output current Is is less than the first threshold value V1, and the switch S is in the off state, so the compensation current Icomp is zero; at t1-t4, it works in light load mode. At t1, the optocoupler output current Is exceeds the first threshold value V1, then the switch S and the first compensation switch K1 are turned on, and current compensation begins. The compensation current Icomp increases to the first compensation current at t2, and at the same time, the optocoupler output current Is begins to decrease until it decreases to the minimum at t2. At t2-t3, the optocoupler output current Is and the compensation current Icomp remain unchanged; at t4-t7, it works in ultra-light load mode. At t4, the sum of the optocoupler output current Is and the compensation current Icomp exceeds the second threshold value V2, then the switch S and the first compensation switch K1 are turned on, and current compensation begins. 1. The second compensation switch K2 is turned on, and the compensation current Icomp increases further, and increases to the second compensation current at t5. At the same time, the optocoupler output current Is begins to decrease, and decreases to the minimum at t5. At t5-t6, the optocoupler output current Is and the compensation current Icomp remain unchanged; at t7-t9, it works in standby mode. At t7, the sum of the optocoupler output current Is and the compensation current Icomp exceeds the third threshold value V3, then the switch S and the first compensation switch K1, the second compensation switch K2 and the third compensation switch K3 are turned on, and the compensation current Icomp increases further, and increases to the third compensation current at t8. At the same time, the optocoupler output current Is begins to decrease, and decreases to the minimum at t8. At t8-t9, the optocoupler output current Is and the compensation current Icomp remain unchanged. Figure 4 It can be seen that by compensating the output current of the optocoupler, the ultrashort wave direction finder tester is less than the threshold value Ith in different working modes.

[0062] like Figure 6 As shown, after adding the small current compensation module, when under-compensation is detected at t2 and t8, the control module in the small current compensation module controls the forward current compensation branch to be turned on in sequence until the optocoupler output current is detected to be equal to 0 to end the compensation; when over-compensation is detected at t5, the control module in the small current compensation module controls the reverse current compensation branch to be turned on in sequence until the optocoupler output current is detected to be greater than 0 to end the compensation. The change process of the compensation current Icomp is shown in FIG. Figure 6 As shown by the blue line in the middle, the change process of the sampling current is as follows Figure 6 As shown by the red line in the middle, it can be seen that by setting a small current compensation module, the optocoupler output current can be kept below Ith', the optocoupler output current compensation is more accurate, and the power loss is smaller.

[0063] Another embodiment of the present invention provides an ultrashort wave direction finder tester, which includes the aforementioned power supply, and also includes a main control module and a display module. The power supply is also connected to the main control module and the display module to power the main control module and the display module.

[0064] The above description of the embodiments is to facilitate the understanding and application of the present invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention should be within the scope of protection of the present invention.

Claims

1. A power supply based on an ultrashort wave direction finder tester, characterized in that: The power supply is an isolated switching power supply, comprising: a power input terminal Vin and an output terminal Vout, the output terminal Vout is connected to the input terminal of a feedback circuit, the feedback circuit is connected to the input terminal of an optocoupler isolation circuit, one output terminal of the optocoupler isolation circuit is connected to an optocoupler current regulation module and a drive circuit module, and the other end is connected to a ground terminal, and the drive circuit module generates a drive signal according to a feedback signal at the output terminal of the optocoupler circuit to control the output of the power circuit of the ultrashort wave direction finder tester; The optocoupler current regulation module includes: a sampling module, whose input end is connected to the output side of the optocoupler isolation circuit; an adding circuit, which adds the output current collected by the sampling module and the compensation current of the current compensation module, and inputs the sum to the mode judgment module; an environment detection module, which detects the working environment of the optocoupler isolation circuit; a threshold setting module, wherein the output end of the environment detection module is connected to the threshold setting module, and the threshold setting module sets the corresponding threshold output function according to the working mode of the tester power supply based on the temperature characteristics of the optocoupler isolation circuit, and the other input end of the mode judgment module is connected to the threshold setting module, and the threshold setting module distributes the adjusted thresholds of each mode to the mode judgment module. The mode judgment module performs mode judgment based on the adjusted threshold value, and the output end of the mode judgment module is respectively connected to the control end of the switch module and the current compensation module; the input end of the switch module is connected to the output end of the optocoupler isolation feedback circuit, and the output end of the switch module is connected to the input of the current compensation module, so as to control whether to perform current compensation by controlling the on or off of the switch module; the other end of the current compensation module is connected to the input end of the addition circuit, so as to perform current compensation on the output end of the optocoupler circuit according to different working modes of the tester, and the optocoupler current regulation module also includes a small current compensation module, and the small current compensation module is used to accurately compensate the optocoupler output current after compensation by the current compensation module; The current compensation module includes a plurality of MOS transistors M0-MK, wherein k is an integer greater than or equal to 3, the sources of the plurality of MOS transistors M0, M1...MK are all electrically connected to one end of the switch S, the drain of the MOS transistor M0 is connected to the gate and is grounded through a bias current source, the gate of the MOS transistor M1 is connected to the gate of the MOS transistor M0, and its drain is connected to one end of the first compensation switch K1, and the other end of the first compensation switch K1 is connected to the output end of the compensation current, the gate of the MOS transistor M2 is connected to the gate of the MOS transistor M0, and its drain is connected to one end of the second compensation switch K2, and the other end of the second compensation switch K2 is connected to the output end of the compensation current, the gate of the MOS transistor M3 is connected to the gate of the MOS transistor M0, and its drain is connected to one end of the third compensation switch K3, and the other end of the third compensation switch K3 is connected to the output end of the compensation current, and so on, the gate of the MOS transistor MK is connected to the gate of the MOS transistor M0, and its drain is connected to one end of the Kth compensation switch Kk, and the other end of the Kth compensation switch Kk is connected to the output end of the compensation current.

2. The power supply according to claim 1, characterized in that: The preset working modes of the ultrashort wave direction finder tester include at least a normal mode, a light load mode, an ultra-light load mode and a standby mode. When the output current of the optical coupling isolation circuit collected is less than a first threshold value, the mode judgment module judges that the ultrashort wave direction finder tester is working in the normal mode, controls the switch module to remain in the disconnected state, and the current compensation module does not perform current compensation. The input current of the mode judgment module is equal to the output sampling current; When the sum of the output current and the compensation current is greater than the first threshold and less than the second threshold, it is judged that the tester enters the light load mode. At this time, the switch module is turned on, and the current compensation module is controlled to output the first compensation current; when the sum of the output current and the compensation current is greater than the second threshold and less than the third threshold, it is judged that the tester enters the ultra-light load mode, the switch module is continuously turned on, and the current compensation module is controlled to output the second compensation current; when the sum of the output current and the compensation current is greater than the third threshold, it is judged that the tester enters the standby mode, the switch module is continuously turned on, and the current compensation module is controlled to output the third compensation current, wherein the third compensation current>the second compensation current>the first compensation current.

3. The power supply according to claim 1, characterized in that: The sampling module is a current sensor, and the environmental detection module is a temperature sensor; the small current compensation module includes a current sampling module, a control module, a forward current compensation module and a reverse current compensation module. The current sampling module collects the optocoupler output current, and the control module selects the start and stop of the forward current compensation and / or reverse current compensation by judging the size of the optocoupler output current.

4. The power supply according to claim 3, characterized in that: The threshold function in the threshold setting module is VN=W(T)*Vn, and the temperature characteristic function of the optocoupler isolation circuit is W(T)=Af(T)+B, wherein VN is the adjusted mode threshold, W(T) is the temperature characteristic function of the optocoupler isolation circuit, Vn is the mode threshold under ideal conditions, N and n are both integers greater than or equal to 3, and their sizes depend on the number of working modes of the tester; A is the proportional coefficient, B is the adjustment factor, and f(T) is the current transfer ratio function of the optocoupler isolation circuit, which is related to the temperature characteristics of the optocoupler isolation circuit.

5. The power supply according to claim 4, characterized in that: The mode judgment module includes multiple comparison circuits, which are the first comparator Com1, the second comparator Com2 to the Kth comparator ComK, where k is an integer greater than or equal to 3, the in-phase input terminals of the first comparator Com1 to the Kth comparator ComK are all connected to the output terminal of the adder, and the inverting input terminals of the first comparator Com1 to the Kth comparator ComK are connected to the threshold setting module, which adjusts and allocates the thresholds of different modes; the switch module is a controllable switch circuit or a controllable switch tube; the output terminal of the first comparator Com1 is respectively connected to the control terminal of the switch S and the first compensation switch K1, the output terminal of the second comparator Com2 is connected to the control terminal of the second compensation switch K2, the output terminal of the third comparator Com3 is connected to the control terminal of the third compensation switch K3, and so on, the output terminal of the Kth comparator is connected to the control terminal of the Kth switch.

6. The power supply according to claim 5, characterized in that: The small current compensation module is arranged at the connection between the first compensation switch, the second compensation switch and the third compensation switch; The forward current compensation module is a plurality of forward current compensation branches connected in parallel, and the reverse current compensation module is a plurality of reverse current compensation branches connected in parallel, the forward current compensation branch increases the total compensation current, and the reverse current compensation branch reduces the total compensation current; the forward current compensation branch is a forward current source and a switch connected in series, and the reverse current compensation branch is a reverse current source and a switch connected in series; the absolute values ​​of the forward current source and the reverse current source are both smaller than the bias current source Ib.

7. The power supply according to claim 6, characterized in that: The method for the control module to control the forward current compensation and / or the reverse current compensation is: First, determine the working mode of the tester. After outputting the corresponding first compensation current, second compensation current or third compensation current in light load mode, ultra-light load mode or standby mode, wait for the delay time T. If the detected optocoupler output current Is is greater than 0, close the forward current compensation branch. If the optocoupler output current is still greater than 0, control the closed forward current compensation branch to add 1 until the detected optocoupler output current is equal to 0, then stop adding the forward current compensation branch. After waiting for the delay time T, if the detected optocoupler output current is equal to 0, the reverse current compensation branch is closed. If the optocoupler output current is still equal to 0, the closed reverse current compensation branch is controlled to add 1 until the detected optocoupler output current is greater than 0, then the reverse current compensation branch is stopped. At this time, it indicates that the optimal compensation state is reached.

8. The power supply according to claim 7, characterized in that: The output ends of the multiple comparators are all connected to a timing circuit, which is used to control the corresponding compensation switch to be turned on when the sum of the optocoupler output current and the compensation current is greater than the current threshold for a period of time greater than time T, otherwise the compensation switch is controlled to be in an off state.

9. According to the power supply of claim 7, the output ends of the plurality of comparators are connected to a timing circuit, and the timing circuit is used to control the corresponding compensation switch to turn off when the sum of the optocoupler output current and the compensation current is less than the current threshold for a time greater than T, otherwise the compensation switch is controlled to maintain an on state.

10. An ultrashort wave direction finder tester, comprising the power supply according to any one of claims 1 to 9, characterized in that: It also includes a main control module and a display module, and the power supply is connected to the main control module and the display module to supply power to the main control module and the display module.

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