Protection method and device for power amplifier circuit

Abstract

The invention discloses a protection method and device for a power amplifier circuit. The power amplifier circuit comprises at least two power tubes; the protection method of the power amplifier circuit comprises the following steps: configuring a power threshold value of the power amplifier circuit; acquiring an output voltage value and an output current value of the power amplifier circuit in real time; calculating the real-time power of the power amplifier circuit according to the output voltage value, the output current value and a preset formula; and configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold. According to the invention, the protection reliability of the power amplifier circuit can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power amplifiers, and in particular to a protection method and device for a power amplifier circuit. Background Art

[0002] Power amplifier circuits have important applications in the field of testing technology. For example, they can amplify the tiny signals output by instruments and meters by a specified multiple to become large signals, thereby completing various testing tasks. Therefore, how to protect the power amplifier circuit is particularly important.

[0003] The power amplifier stage of the power amplifier circuit realizes power amplification through the power tube, so the protection of the power amplifier circuit is mainly realized by protecting the power tube. Among them, the temperature of the power tube is positively correlated with the power value on the power tube, that is, the greater the power value on the power tube, the greater the temperature rise of the power tube; correspondingly, the smaller the power value on the power tube, the smaller the temperature rise.

[0004] In the related art, there are two main ways to protect the power amplifier circuit. One is to protect the power amplifier circuit by hardware circuit, such as by adding a circuit to monitor the output power, output current or temperature rise near the power amplifier circuit. When the output power, output current or temperature rise near the power amplifier circuit exceeds the threshold, the power amplifier protection action is triggered. The disadvantage is that it is only implemented by hardware, not easy to debug, and has high cost.

[0005] The second is to protect the power amplifier circuit through a combination of soft and hard methods, such as by measuring the temperature rise curve and the heat dissipation curve and storing them in the controller, and then using the controller to calculate the current temperature value of the power tube according to the relevant formula based on the output power, current output time and initial temperature value of the power tube. However, this method requires obtaining the temperature rise curve and heat dissipation curve of the power tube in advance. Different models of power tubes have different corresponding temperature rise curves, and when the power amplifier circuit is used in different circuits, the corresponding heat dissipation curve is also different, which makes this method limited and unreliable. Summary of the invention

[0006] The present invention provides a method and device for protecting a power amplifier circuit, so as to improve the reliability of protecting the power amplifier circuit and reduce the cost.

[0007] According to one aspect of the present invention, a protection method for a power amplifier circuit is provided, wherein the power amplifier circuit includes at least two power tubes; the protection method for the power amplifier circuit includes:

[0008] Configuring a power threshold of the power amplifier circuit;

[0009] Acquire the output voltage value and output current value of the power amplifier circuit in real time;

[0010] Calculating the real-time power of the power amplifier circuit according to the output voltage value, the output current value and a preset formula;

[0011] The working state of the power amplifier circuit is configured according to the relationship between the real-time power and the power threshold.

[0012] Optionally, configuring a power threshold of the power amplifier circuit includes:

[0013] The DC power threshold and the pulse power threshold of the power tube at different shell temperatures are determined according to the SOA curves of the at least two power tubes.

[0014] Optionally, the calculating the real-time power of the power amplifier circuit according to the output voltage value, the output current value and a preset formula includes:

[0015] Determine the output current value of each power tube of the at least two power tubes according to the output current value;

[0016] Determine the real-time average power of the at least two power tubes within a power calculation period according to the output current value of each power tube, the output voltage value and a first preset formula;

[0017] The real-time power of the power amplifier circuit is calculated using the maximum value of the real-time average power of the at least two power tubes.

[0018] Optionally, the first preset formula is:

[0019]

[0020] Among them, P is the real-time average power of the power tube, V is the power supply voltage corresponding to the power tube, Req is the resistance on the output circuit of the power tube, Vout is the output voltage value corresponding to the power tube, Iout is the output current value corresponding to the power tube, and N is the number of sampling times in a power calculation cycle, wherein N≥1.

[0021] Optionally, the at least two power tubes include a first power tube and a second power tube, a first end of the first power tube is connected to a first power supply voltage, a first end of the second power tube is connected to a second power supply voltage, and at least the second end of the first power tube and the second end of the second power tube are electrically connected to serve as the output end of the power amplifier circuit;

[0022] Determining the output current of each of the at least two power tubes according to the output current value includes:

[0023] According to the polarity of the output current value of the power tube, it is determined whether the output current value is output by the first power tube or the second power tube.

[0024] Optionally, calculating the real-time power of the power amplifier circuit by using the maximum value of the real-time average power of the at least two power tubes includes:

[0025] The maximum value of the real-time average power is multiplied by the number of sampling times of a power calculation cycle and then scaled by a preset multiple to be used as the real-time power of the power amplifier circuit.

[0026] Optionally, configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold includes:

[0027] If the real-time power is less than or equal to the corresponding DC power threshold and the corresponding pulse power threshold, configuring the power amplifier circuit to be in a normal state;

[0028] When the power amplifier circuit is in a normal state, if the real-time power is greater than the DC power threshold and less than the pulse power threshold, the power amplifier circuit is configured to enter a pre-protection state; if the real-time power is greater than the pulse power threshold, the power amplifier circuit is configured to directly enter a protection state; wherein, in the protection state, the output current of the power amplifier circuit is reduced; and in the pre-protection state, the power amplifier circuit is maintained to operate in the current state for a first preset time.

[0029] Optionally, configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold further includes:

[0030] In the pre-protection state, if the real-time power of the power amplifier circuit in the next power calculation cycle is greater than the DC power threshold, or the sum of the real-time power of the power amplifier circuit in the next power calculation cycle, the real-time power of the current power calculation cycle and the real-time power of the previous power calculation cycle is greater than N times the real-time power of the current power calculation cycle, the power amplifier circuit is configured to enter the protection state; otherwise, the power amplifier circuit is configured to return to the normal state; N is greater than or equal to 2.

[0031] Optionally, configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold further includes:

[0032] After the protection state is maintained for a second preset time, the power amplifier circuit is configured to enter a delay state; after the delay state is maintained for a third preset time, the power amplifier circuit is configured to enter a waiting state; in the waiting state, if a preset exit condition is met, the power amplifier circuit is configured to enter a deprotection state, and after the deprotection state is maintained for a fourth preset time, the power amplifier circuit is configured to enter the normal state;

[0033] Wherein, in the delay state and the waiting state, the power amplifier circuit is configured to work in the current state.

[0034] According to another aspect of the present invention, a protection device for a power amplifier circuit is provided. The protection device for a power amplifier circuit comprises the power amplifier circuit and a controller. The controller is used to execute the protection method for the power amplifier circuit as described above.

[0035] The technical solution of the embodiment of the present invention adopts a method for protecting a power amplifier circuit, including configuring a power threshold of the power amplifier circuit; obtaining the output voltage value and output current value of the power amplifier circuit in real time; calculating the real-time power of the power amplifier circuit according to the output voltage value, the output current value and a preset formula; and configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold. The real-time power is directly compared with the power threshold to protect the power amplifier circuit, avoiding the solution of using a temperature curve, which can improve the reliability of protection, and can timely and effectively protect the power amplifier circuit, thereby reducing costs.

[0036] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 A flow chart of a method for protecting a power amplifier circuit provided by an embodiment of the present invention;

[0039] Figure 2 A schematic diagram of the circuit structure of a power amplifier circuit provided by an embodiment of the present invention;

[0040] Figure 3 A schematic diagram of the circuit structure of a VI source provided by an embodiment of the present invention;

[0041] Figure 4 A flowchart of another power amplifier circuit protection method provided by an embodiment of the present invention;

[0042] Figure 5 This is a diagram showing the relationship between the various states of the power amplifier circuit. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0044] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0045] Figure 1 A flowchart of a method for protecting a power amplifier circuit provided by an embodiment of the present invention, Figure 2 A schematic diagram of a circuit structure of a power amplifier circuit provided by an embodiment of the present invention, referring to Figure 1 and Figure 2 The power amplifier circuit includes at least two power tubes; at least two power tubes are push-pull arranged; when the power amplifier circuit includes multiple power tubes, it can include 2K power tubes, K is an integer greater than or equal to 1, and they are push-pull arranged in pairs; or, at least two power tubes include a first power tube and a second power tube that are push-pull arranged, and any other power tube is connected in parallel with the first power tube or in parallel with the second power tube.

[0046] The protection method of the power amplifier circuit of the present invention comprises:

[0047] Step S101, configuring the power threshold of the power amplifier circuit;

[0048] Specifically, the protection method of the power amplifier circuit can be executed by a controller. In addition to protecting the power amplifier circuit, the controller can also control the state of the power amplifier circuit, such as controlling the output voltage and output current of the power amplifier circuit. Before the power amplifier circuit works, the power threshold of the power amplifier circuit can be configured inside the controller. The power threshold of the power amplifier circuit represents the threshold at which the power amplifier circuit can work normally. If the power value on the power amplifier circuit is greater than or equal to the power threshold, it indicates that the power of the power amplifier circuit is too large and there is a risk of damage; if the power value on the power amplifier circuit is less than the power threshold, the power amplifier circuit can work normally. In this embodiment, the power threshold can be stored in a storage medium in the controller.

[0049] It should be noted that in this embodiment, the power threshold is configured in the controller. In other embodiments, the user can configure the power threshold in the host computer as needed. The specific configuration method is shown in the following embodiment and is not introduced in detail here.

[0050] Step S102, obtaining the output voltage value and output current value of the power amplifier circuit in real time;

[0051] Specifically, the output voltage value and the output current value of the power amplifier circuit are the voltage value and the current value at the output end of the power amplifier circuit, such as Figure 2 As shown, the output voltage value Vo and the output current value Io of the power amplifier circuit can be sampled by the sampling circuit. The controller obtains the output voltage value Vo and the output current value Io from the sampling circuit in real time.

[0052] Step S103, calculating the real-time power of the power amplifier circuit according to the output voltage value, the output current value and a preset formula;

[0053] Specifically, the controller stores a preset formula for calculating the real-time power of the power amplifier circuit. When the output voltage value Vo and the output current value Io are obtained, the real-time power of the power amplifier circuit is calculated in real time. In this embodiment, the real-time power of the power amplifier circuit is directly calculated by the controller without the need to interact with the host computer.

[0054] Step S104, configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold.

[0055] Specifically, after the controller calculates the real-time power of the power amplifier circuit, it can compare the real-time power with the pre-stored power threshold, and then control the power amplifier circuit according to whether the real-time power exceeds the power threshold, so as to protect the power amplifier circuit. From the above analysis, it can be seen that the protection method of the power amplifier circuit of this embodiment is not based on the calculation and analysis of the temperature curve of the power tube for power protection, so there is no problem of inaccurate temperature calculation due to voltage drop and unreliable protection of the power amplifier circuit. In addition, power protection is not performed based on the heating curve and the heat dissipation curve, but the relationship between the real-time power and the power threshold is directly compared, which can be applied to any power tube, so the protection range of the power amplifier circuit is not limited. And because the temperature transmission has a delay, when the power amplifier circuit is subjected to a sudden high-power pulse, the temperature of the power tube in the power amplifier circuit rises rapidly, causing the power amplifier circuit to fail, but because the temperature is not transmitted to the outside in time, the protection action will fail. In this embodiment, the power threshold and the real-time power are directly used for calculation, and when the power amplifier circuit is subjected to a sudden high power, the power amplifier circuit can be protected in time. In addition, the protection of the power amplifier circuit in this embodiment directly utilizes the output power of the power amplifier circuit, which can improve the protection efficiency of the power amplifier circuit, such as increasing the output response speed of the VI source, thereby improving the test efficiency.

[0056] The technical solution of this embodiment adopts a method for protecting a power amplifier circuit, including configuring a power threshold of the power amplifier circuit; obtaining the output voltage value and output current value of the power amplifier circuit in real time; calculating the real-time power of the power amplifier circuit according to the output voltage value, the output current value and a preset formula; and configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold. The real-time power is directly compared with the power threshold to protect the power amplifier circuit, which reduces the hardware cost, avoids the solution of using a temperature curve, can improve the reliability of protection, and can timely and effectively protect the power amplifier circuit, thereby improving the protection efficiency.

[0057] Optionally, to facilitate the subsequent description of the protection method, an application scenario of the power amplifier circuit is first introduced below. Figure 3 As shown, Figure 3A circuit structure diagram of a VI source provided by an embodiment of the present invention. The VI source is also a voltage and current source, and the VI source can be applied to the field of ATE (Automatic Test Equipment). The VI source may specifically include a controller, a main DAC, a NULL stage, an integral stage, a power amplifier circuit, a power amplifier power supply, a clamping DAC, a clamping circuit, a temperature sensor, and an ADC. The temperature sensor is electrically connected to the controller to obtain the shell temperature of the power tube. The controller may be an FPGA or an MCU, etc., which is used to communicate with a host computer to control the power amplifier circuit. The output signal of the power amplifier circuit is converted into a digital-to-analog converter by the main DAC, and is subtracted from the output signal OUT of the VI source, and the difference is output to the NULL stage. The NULL stage amplifies the error, and controls the output of the power amplifier circuit after integration through the integral stage. In addition, the controller converts the clamping signal into an analog value through the clamping DAC, and outputs it to the clamping circuit. The clamping circuit controls the input of the integral stage according to the clamping signal, thereby clamping the output current of the power amplifier circuit. In addition, the VI source can sample the output current value Io and the output voltage value Vo in the output signal OUT using ADC and convert them into digital signals and then feed them back to the controller. The controller controls the power on and off of the power amplifier power supply, and the power amplifier power supply supplies power to the power amplifier circuit. The specific functions and circuit structures of each module in the above-mentioned VI source are well known to those skilled in the art and will not be repeated here. It should be noted that the power amplifier circuit of this embodiment can be applied not only to the VI source, but also to high-power power amplifier circuits or radio frequency power amplifier circuits.

[0058] In the above implementation, the protection method of the power amplifier circuit is executed by the controller, which is implemented in a software manner, and does not require additional hardware for the application scenario of the power amplifier circuit, thereby reducing the cost of protecting the power amplifier circuit. Exemplarily, the controller can be an FPGA (Field Programmable Gate Array). The controller is implemented using FPGA, which not only has a lower cost, but also can improve the efficiency of executing the protection method of the power amplifier circuit.

[0059] Optionally, configuring a power threshold of a power amplifier circuit includes:

[0060] The DC power threshold and the pulse power threshold of the power tube at different shell temperatures are determined according to the SOA (Safe Operating Area) curves of at least two power tubes.

[0061] Specifically, the SOA curve of the power tube refers to the current-voltage range in which the power tube can work normally without being damaged. The SOA curve of the power tube can be obtained from the data sheet of the power tube. In this embodiment, the upper computer can be used to configure the power thresholds corresponding to different shell temperatures. Specifically, the low shell temperature threshold Tc_low and the high shell temperature threshold Tc_high of the power tube can be configured first, and the corresponding power thresholds are different under different shell temperatures. Among them, when the shell temperature is less than the low shell temperature threshold, the power threshold is the high DC power threshold Pdc_high and the high pulse power threshold Ppulse_high; when the shell temperature is greater than or equal to the low shell temperature threshold, and less than the high shell temperature threshold, the power threshold is the low DC power threshold Pdc_low and the low pulse power threshold Ppulse_low. The high shell temperature threshold Tc_high is greater than the low shell temperature threshold Tc_low, and its specific value can be determined according to the type of power tube. The power threshold corresponding to the low shell temperature threshold is greater than the power threshold corresponding to the high shell temperature threshold, that is, the high DC power threshold Pdc_high is greater than the low DC power threshold Pdc_low, and the high pulse power threshold Ppulse_high is greater than the low pulse power threshold Ppulse_low. In this embodiment, different power thresholds are set at different shell temperatures, so that the shell temperature and the power have a certain corresponding relationship, thereby ensuring the accuracy of the protection of the power amplifier circuit. In this embodiment, each power tube can be configured with the DC power threshold and pulse power threshold of the power tube at different shell temperatures according to the corresponding SOA curve. The minimum value of the DC power threshold of at least two power tubes in the power amplifier circuit can be configured as the DC power threshold of the power amplifier circuit, and the minimum value of the pulse power threshold of at least two power tubes can be configured as the pulse power threshold of the power amplifier circuit. Of course, the power threshold of the power amplifier circuit can also be configured in other ways.

[0062] Optionally, Figure 4 A flowchart of another power amplifier circuit protection method provided by an embodiment of the present invention, referring to Figure 4 In this embodiment, step S102, i.e., the step of calculating the real-time power of the power amplifier circuit according to the output voltage value, the output current value and the preset formula, specifically includes:

[0063] Step S1021, determining the output current value of each power tube of at least two power tubes according to the output current value;

[0064] Specifically, the power amplifier circuit may include at least two power tubes. Figure 2Taking the power amplifier circuit shown in the figure as an example, at least one power tube includes a first power tube Q1 and a second power tube Q2; the first end of the first power tube Q1 is connected to the first power supply voltage V+, the first end of the second power tube Q2 is connected to the second power supply voltage V-, and at least the second end of the first power tube Q1 and the second end of the second power tube Q2 are electrically connected as the output end of the power amplifier circuit; wherein the first power supply voltage V+ and the second power supply voltage V- are provided by the power supply. Figure 2 The resistor Req on the output circuit of the power tube is shown as an example. The circuit resistance Req can be understood as the resistance of the circuit between the second end of the first power tube and the output end of the power amplifier circuit. The circuit resistance Req needs to be determined according to the specific circuit used by the power amplifier circuit. In addition, Figure 2 In the figure, it is shown by way of example that the control ends of two power tubes in the power amplifier circuit are connected to the power signal PA_IN to be amplified, and the amplified signal PA_OUT is generated after amplification by the power tube, and the amplified signal PA_OUT finally forms an output voltage and an output current at the output end. Among them, the output end of the power amplifier circuit is connected to the device under test (DUT). The first power tube Q1 and the second power tube Q2 are of different types, such as the first power tube Q1 is a P-type transistor, and the second power tube Q2 is an N-type transistor. The control end of the first power tube Q1 and the control end of the second power tube Q2 can also be connected to a bias circuit. And at the same time, only one power tube is turned on, and the other power tube is turned off. When different power tubes are turned on, the polarity of the output current of the power amplifier circuit is different. Therefore, it can be determined whether the output current value is output by the first power tube or the second power tube according to the polarity of the output current value of the power tube.

[0065] It should be noted that, when there are two power tubes in the application, in the present invention, the second end of the first power tube Q1 and the second end of the second power tube Q2 can be directly electrically connected to serve as the output end of the power amplifier circuit, or a corresponding resistor can be added to the circuit after the second end of the first power tube Q1 and the second end of the second power tube Q2 are electrically connected, and the output end corresponding to the resistor is used as the output end of the power amplifier circuit; in other embodiments, the determination of the output end of the power amplifier circuit is not specifically limited, and the output end of the power amplifier circuit can be determined according to the number of selected power tubes and the overlapping method. Regardless of the determination method, it belongs to the scope of protection of the present invention.

[0066] More specifically, for example, when the first power tube Q1 is turned on, the current direction is from the first end of the first power tube to the output end of the power amplifier circuit, and the output current value of the power amplifier circuit is positive; when the second power tube Q2 is turned on, the current direction is from the output end of the power amplifier circuit to the first end of the second power tube Q2, and the output current value of the power amplifier circuit is negative. Furthermore, if the output current of the power amplifier circuit is Iout, the output current of the first power tube Q1 is:

[0067]

[0068] The output current of the second power tube Q2 is:

[0069]

[0070] It should be noted that at each sampling moment, the output current value Iout of the power amplifier circuit is obtained, and then the output current value of the first power tube Q1 and the second power tube Q2 at each sampling moment can be calculated. The real-time power is calculated based on the obtained real-time output current value to achieve real-time protection of the power tube.

[0071] Step S1022, determining the real-time average power of each power tube within a power calculation period according to the output current value, the output voltage value and the first preset formula of each power tube;

[0072] Specifically, the preset formula includes a first preset formula, which is used to calculate the real-time average power of the power tube in a power calculation cycle. In this embodiment, the real-time average power of each power tube in a power calculation cycle is first calculated, and each calculation cycle may include multiple sampling moments.

[0073] Step S1023, using the maximum value of the real-time average power of at least two power tubes to calculate the real-time power of the power amplifier circuit.

[0074] Specifically, the real-time power of each power tube in the power amplifier circuit may be different. In this embodiment, the real-time power of the power amplifier circuit is calculated using the maximum value of the real-time average power of each power tube in a power calculation cycle, which can meet the protection of all power tubes in the power amplifier circuit. In addition, in this embodiment, the power of each power tube in the power amplifier circuit is calculated. Compared with calculating the power of all power tubes in the power amplifier circuit as a whole, by calculating the real-time average power of each power tube, the accuracy of the power amplifier protection can be higher.

[0075] Optionally, the first preset formula is:

[0076]

[0077] Among them, P is the real-time average power of the power tube, V is the power supply voltage corresponding to the power tube, Req is the resistance on the output line of the power tube, Vout is the output voltage value corresponding to the power tube, Iout is the output current value corresponding to the power tube, and N is the number of sampling times in a power calculation cycle, where N≥1.

[0078] Specifically, a power calculation cycle may be, for example, 2.5 ms, and the value of N may be, for example, 2500. For the first power tube Q1, its real-time average power is:

[0079]

[0080] For the second power tube Q2, its real-time average power is:

[0081]

[0082] It should be noted that V represents the absolute value of V+ / V- corresponding to the power tube under different voltage levels. For example, when the voltage level is below 40V, V can represent 48V; when the voltage level is 80V, the power amplifier power supply V can be expressed as +88V, or -8V. The size of the corresponding power amplifier power supply V can be determined according to the different voltage levels set, and no specific limitation is made here.

[0083] In this embodiment, the real-time power of the power amplifier circuit is directly calculated, which is independent of the corresponding relationship between temperature and power and is not limited to the type or model of the power tube. This improves the protection range of the power amplifier circuit, while also improving the VI source output response speed and the test efficiency.

[0084] Furthermore, the preset formula also includes a second preset formula, and the second preset formula is used to calculate the maximum value of the real-time average power of at least two power tubes. For example, when the at least two power tubes include the first power tube Q1 and the second power tube Q2, the second preset formula is: P = max (Pp, Pn). That is, the maximum value of the real-time average power of the first power tube Q1 and the second power tube Q2 in a power calculation cycle: P = max (Pp, Pn).

[0085] Furthermore, calculating the real-time power of the power amplifier circuit using the maximum value of the real-time average power in at least two power tubes includes: multiplying the maximum value of the real-time average power by the number of sampling times of a power calculation cycle and scaling it by a preset multiple as the real-time power of the power amplifier circuit.

[0086] Specifically, the specific value of the real-time average power may be small, so the maximum value of the real-time average power can be amplified. First, it can be multiplied by the number of samples in a power calculation cycle. For example, in a power calculation cycle, Pp>Pn, then the real-time power of the power amplifier circuit P(k)=Pp*N*2 21 , where k is the kth power calculation cycle, which is amplified so that it can be processed normally by the controller. The amplification factor is, for example, 2^21. Of course, in some embodiments, the amplification factor can also be other values. In other embodiments, the real-time power of the power amplifier circuit can be obtained by multiplying the maximum value of the real-time average power by the number of sampling times of a power calculation cycle and reducing it by a preset multiple.

[0087] In addition, to match this, the DC power threshold and the pulse power threshold are also multiplied by N*221 , thus unifying the dimension with the real-time power.

[0088] For example, the following formula is used to set the corresponding relationship between the DC power threshold and the high DC power threshold and the low DC power threshold under different shell temperatures, and the corresponding relationship between the pulse power threshold and the high pulse power threshold and the low pulse power threshold under different shell temperatures. In this embodiment, by determining the corresponding relationship, it is possible to obtain different power protection thresholds corresponding to different shell temperatures, and then the DC power threshold Pth_dc and the pulse power threshold Pth_pulse are amplified to achieve the unification of the dimension with the real-time power P(k). Through the segmented design of power, the temperature and power have a certain corresponding relationship, which ensures the accuracy of protection analysis and judgment.

[0089]

[0090] It should be noted that after receiving the output current value and the output voltage value, the controller will calculate the real-time power of the power amplifier circuit in real time, and in the process, simultaneously calculate the real-time average power of the first power tube Q1 and the second power tube Q2.

[0091] Optionally, configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold includes:

[0092] If the real-time power is less than the corresponding DC power threshold and the corresponding pulse power threshold, the power amplifier circuit is configured to be in a normal state.

[0093] Specifically, if the controller determines that the real-time power is small, that is, smaller than the DC power threshold and pulse power threshold corresponding to the current shell temperature, the power tube does not need to be protected at this time, so the power amplifier circuit can be controlled to maintain a normal state. In the normal state, the power amplifier circuit amplifies the input signal normally according to the setting.

[0094] Furthermore, if Figure 5 As shown, Figure 5 It is a relationship diagram between various states of the power amplifier circuit. When the power amplifier circuit is in a normal state, if the real-time power is greater than the DC power threshold and less than the pulse power threshold, the power amplifier circuit is configured to enter the pre-protection state.

[0095] Specifically, in the normal working state, if P(k) < Pth_pulse and P(k) > Pth_dc, it indicates that the real-time power of the power amplifier circuit is relatively large and there may be a risk of damage. Therefore, it can first enter the pre-protection state. In the pre-protection state, the power amplifier circuit is maintained to work in the current state for a first preset time. The first preset time is, for example, 2.5 ms (of course, the SOA curves corresponding to different power transistors are different, and the first preset time can also be different). That is to say, when entering the pre-protection state, the power amplifier circuit will still maintain the current state for at least 2.5 ms, allowing the power amplifier circuit to work for a period of time in the state where P(k) < Pth_pulse and P(k) > Pth_dc, and no protection such as current limiting will be performed on the power amplifier circuit during this period.

[0096] In the normal working state, if the real-time power is greater than the pulse power threshold, the power amplifier circuit is configured to directly enter the protection state.

[0097] Specifically, the comparison between the real-time power and the pulse power threshold and the comparison between the real-time power and the DC power threshold are carried out simultaneously. In the normal state, when it is known that P(k) < Pth_pulse and P(k) > Pth_dc, it will enter the pre-protection. If it is detected that P(k) > Pth_pulse, it means that the power value of the power amplifier circuit is relatively large at this time and the risk of damage is relatively high. Therefore, it can directly enter the protection state. Among them, in the protection state, the output current of the power amplifier circuit is reduced. More specifically, when entering the protection state, if the current working mode of the VI source is FVCI (constant voltage current clamping), the controller performs corresponding protection actions according to the current current gear of the VI source. For example, if the current gear of the VI source ≥ 100 mA, the output value of the clamping DAC can be configured to make the current of the power amplifier circuit clamp ±10 mA. If the current mode is FICV (constant current voltage clamping), the controller can configure the output value of the main DAC according to the current gear, such as the gear ≥ 100 mA, to make the power amplifier circuit have a constant current of 0. That is to say, the output current of the power amplifier circuit can be controlled by configuring the main DAC or the clamping DAC, thereby reducing the power of the power amplifier circuit and protecting the power amplifier circuit.

[0098] It should be noted that in this embodiment, the DC power threshold Pth_dc is less than the pulse power threshold Pth_pulse. Therefore, when the real-time power is greater than the pulse power threshold Pth_pulse, it must be greater than the DC power threshold Pth_dc.

[0099] Optionally, in the protection state, the controller can send a power protection alarm signal to the host computer.

[0100] Optionally, when the controller of the VI source receives an instruction to change the loop state and the working state is in a loop state change, such as when the VI source is in a gear switching, SET value changing, or relay switching state, the configuration amplifier circuit will not enter the protection state. When the working state of the VI source does not belong to the above working states, it can be determined whether to enter the protection state according to the real-time power.

[0101] Optionally, in the protection state, the controller will not accept any instructions.

[0102] Optionally, after entering the protection state, a corresponding protection action is performed after a certain delay, thereby ensuring that the VI source is stable and avoiding relay thermal cutting.

[0103] Optionally, continue to refer to Figure 5 , in the pre-protection state, if the real-time power of the power amplifier circuit in the next power calculation cycle is greater than the DC power threshold, or the sum of the real-time power of the power amplifier circuit in the next power calculation cycle, the real-time power of the current power calculation cycle and the real-time power of the previous power calculation cycle is greater than N times the real-time power of the current power calculation cycle, then the power amplifier circuit is configured to enter the protection state; otherwise, the power amplifier circuit is configured to return to the normal working state; N is greater than or equal to 2. That is to say, after the pre-protection state is maintained for the first preset time, if it is judged that P(k+1)>Pth_dc or it is judged that P(k+1)+P(k)+P(k-1)>N*Pth_dc, it indicates that if the power amplifier circuit continues to work in the current state, the risk of damage will be greatly increased, and thus it can enter the protection state. On the contrary, it indicates that the risk of damage to the power amplifier circuit is decreasing, and thus it can return to the normal working state. Exemplarily, N is equal to 2.

[0104] Optionally, after the protection state is maintained for a second preset time, the power amplifier circuit is configured to enter a delay state; after the delay state is maintained for a third preset time, the power amplifier circuit is configured to enter a waiting state; in the waiting state, if a preset exit condition is met, the power amplifier circuit is configured to enter a deprotection state, and after the deprotection state is maintained for a fourth preset time, the power amplifier circuit is configured to enter a normal state; wherein, in the delay state and the waiting state, the power amplifier circuit is configured to operate in the current state.

[0105] Specifically, the second preset time may be the same as or different from the first preset time, and the third preset time may be the same as or different from the first preset time. In the delay state and the waiting state, the power amplifier circuit still maintains the constant current configuration in the protection state. In the waiting state, if the preset exit condition is met, the protection state is entered, and if the preset exit condition is not met, the waiting state is continued. Exemplarily, in the FCVI mode, the exit condition is, for example, that the controller receives a new instruction to change the loop state sent by the host computer; in the FIVC mode, the exit condition is, for example, that the controller receives a new instruction to change the loop state sent by the host computer. Among them, in the protection state, the corresponding exit action is performed, and the duration of the protection state is short, for example, a clock cycle of the controller, for example, 8ns, so that the controller exits the protection state as soon as possible, so that the power amplifier circuit continues to work normally. In different working modes, the corresponding protection action of the protection state is different. For example, in the FCVI mode, the protection action includes the controller changing the loop state according to the instruction, and after the process is completed, the clamping DAC output value of the last instruction is immediately restored. In the FICV mode, the protection action includes the controller changing the loop state according to the instruction. In addition, the waiting state and the exit condition can be asynchronous. When the protection exit action is completed, the normal working state is entered.

[0106] It should be noted that in some embodiments, the pre-protection state may not be set, but the protection state may be directly entered from the normal working state when the corresponding conditions are met. Figure 5 In the state diagram shown, the normal state and the waiting state can be entered and exited at any time, and the protection state, delay state and pre-protection state need to last for a first preset time, such as 2.5ms before they can be exited. The protection exit state needs to last for one clock cycle of the controller, that is, 1CLK, such as 8ns before it can be exited.

[0107] As shown in Table 1, Table 1 is a correspondence table between controller instructions and states of power amplifier circuits provided by an embodiment of the present invention. Among them, the controller instructions on the states of the power amplifier circuits include:

[0108] When the power amplifier circuit is in normal state, the controller is in the "01" instruction;

[0109] When the power amplifier circuit is in protection state, the controller is "00" instruction;

[0110] When the power amplifier circuit is in the delay state, the controller is the "00" instruction;

[0111] When the power amplifier circuit is in the pre-protection state, the controller is in the "01" instruction;

[0112] When the power amplifier circuit is in the waiting state, the controller Wie "10" instruction.

[0113] Table 1

[0114]

[0115]

[0116] The power amplifier circuit protection action provided in this embodiment does not directly power off the power amplifier circuit when a large current exists in the power amplifier circuit, but performs a protection deactivation operation, thereby making the protection of the power amplifier circuit more reliable.

[0117] The present invention also provides a protection device for a power amplifier circuit, such as Figure 3 As shown, the protection device of the power amplifier circuit includes a power amplifier circuit and a controller, and the controller is used to execute the protection method of the power amplifier circuit provided by any embodiment of the present invention.

[0118] The specific working principle of the protection device of the power amplifier circuit can refer to the description of the protection method of the power amplifier circuit in the present invention. The protection device has the same beneficial effects as the protection method, which will not be described in detail here.

[0119] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0120] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for protecting a power amplifier circuit, characterized in that: The power amplifier circuit includes at least two power tubes; the protection method of the power amplifier circuit includes: Configuring a power threshold of the power amplifier circuit; Acquire the output voltage value and output current value of the power amplifier circuit in real time; Calculating the real-time power of the power amplifier circuit according to the output voltage value, the output current value and a preset formula; The working state of the power amplifier circuit is configured according to the relationship between the real-time power and the power threshold.

2. The method for protecting a power amplifier circuit according to claim 1, characterized in that: The configuring the power threshold of the power amplifier circuit comprises: The DC power threshold and the pulse power threshold of the power tube at different shell temperatures are determined according to the SOA curves of the at least two power tubes.

3. The method for protecting a power amplifier circuit according to claim 1, characterized in that: The calculating the real-time power of the power amplifier circuit according to the output voltage value, the output current value and a preset formula includes: Determine the output current value of each power tube of the at least two power tubes according to the output current value; Determine the real-time average power of the at least two power tubes within a power calculation period according to the output current value of each power tube, the output voltage value and a first preset formula; The real-time power of the power amplifier circuit is calculated using the maximum value of the real-time average power of the at least two power tubes.

4. The method for protecting a power amplifier circuit according to claim 3, characterized in that: The first preset formula is: Among them, P is the real-time average power of the power tube, V is the power supply voltage corresponding to the power tube, Req is the resistance on the output circuit of the power tube, Vout is the output voltage value corresponding to the power tube, Iout is the output current value corresponding to the power tube, and N is the number of sampling times in a power calculation cycle, wherein N≥1.

5. The method for protecting a power amplifier circuit according to claim 3, characterized in that: The at least two power tubes include a first power tube and a second power tube, a first end of the first power tube is connected to a first power supply voltage, a first end of the second power tube is connected to a second power supply voltage, and at least a second end of the first power tube and a second end of the second power tube are electrically connected to serve as an output end of the power amplifier circuit; Determining the output current of each of the at least two power tubes according to the output current value includes: According to the polarity of the output current value of the power tube, it is determined whether the output current value is output by the first power tube or the second power tube.

6. The method for protecting a power amplifier circuit according to claim 3, characterized in that: Calculating the real-time power of the power amplifier circuit using the maximum value of the real-time average power of the at least two power tubes includes: The maximum value of the real-time average power is multiplied by the number of sampling times of a power calculation cycle and then scaled by a preset multiple to be used as the real-time power of the power amplifier circuit.

7. The method for protecting a power amplifier circuit according to claim 2, characterized in that: Configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold comprises: If the real-time power is less than or equal to the corresponding DC power threshold and the corresponding pulse power threshold, configuring the power amplifier circuit to be in a normal state; When the power amplifier circuit is in a normal state, if the real-time power is greater than the DC power threshold and less than the pulse power threshold, the power amplifier circuit is configured to enter a pre-protection state; if the real-time power is greater than the pulse power threshold, the power amplifier circuit is configured to directly enter a protection state; wherein, in the protection state, the output current of the power amplifier circuit is reduced; and in the pre-protection state, the power amplifier circuit is maintained to operate in the current state for a first preset time.

8. The method for protecting a power amplifier circuit according to claim 7, characterized in that: The configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold further includes: In the pre-protection state, if the real-time power of the power amplifier circuit in the next power calculation cycle is greater than the DC power threshold, or the sum of the real-time power of the power amplifier circuit in the next power calculation cycle, the real-time power of the current power calculation cycle and the real-time power of the previous power calculation cycle is greater than N times the real-time power of the current power calculation cycle, the power amplifier circuit is configured to enter the protection state; otherwise, the power amplifier circuit is configured to return to the normal state; N is greater than or equal to 2.

9. The method for protecting a power amplifier circuit according to claim 7, characterized in that: The configuring the working state of the power amplifier circuit according to the relationship between the real-time power and the power threshold further includes: After the protection state is maintained for a second preset time, the power amplifier circuit is configured to enter a delay state; after the delay state is maintained for a third preset time, the power amplifier circuit is configured to enter a waiting state; in the waiting state, if a preset exit condition is met, the power amplifier circuit is configured to enter a deprotection state, and after the deprotection state is maintained for a fourth preset time, the power amplifier circuit is configured to enter the normal state; Wherein, in the delay state and the waiting state, the power amplifier circuit is configured to work in the current state.

10. A protection device for a power amplifier circuit, characterized in that: The protection device for the power amplifier circuit comprises the power amplifier circuit and a controller, and the controller is used to execute the protection method for the power amplifier circuit according to any one of claims 1 to 9.

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