Current sampling circuit and radio frequency power supply

Abstract

The invention provides a current sampling circuit and a radio frequency power supply. The current sampling circuit comprises a first sampling resistor, a second sampling resistor, a sampling power supply and a current sampling control unit, the first sampling resistor is connected with a power supply and a load; the second sampling resistor is connected with the voltage output end of the sampling power supply and a load; the current sampling control unit is connected with the first sampling resistor, the second sampling resistor and the sampling power supply. And the current sampling control unit is used for controlling the sampling power supply to boost the output voltage under the first working condition until the current direction of the first sampling current flowing through the first sampling resistor is detected to be overturned, and acquiring the second sampling current flowing through the second sampling resistor as the load current to be output when the current direction is overturned. And the current sampling control unit is also used for acquiring the first sampling current as load current output under the second working condition. According to the invention, wide-range and high-precision current detection can be realized.

Description

Technical Field

[0001] This application relates to the field of electronic power technology, and in particular to a current sampling circuit and a radio frequency power supply. Background Technology

[0002] With the widespread application of electronic circuit technology, the design requirements for load power are becoming increasingly demanding. High-power loads often require high-power chips such as AI chips and network chips to provide higher power and stronger processing capabilities, resulting in larger load currents flowing through the load. Therefore, when sampling the load current, it is necessary to accurately measure not only ampere (A) level load currents under full-load operation but also milliampere (mA) level load currents under sleep or low-power operation. Thus, load current measurements often need to achieve 1% or higher accuracy across the entire range from a few mA to several hundred A. Figure 1 Since the sampling resistor is connected in series with the load, it can be determined that the load current is equal to the sampling current flowing through the sampling resistor. Load current sampling can be achieved by sampling the current through the sampling resistor. Furthermore, the operational amplifier circuit can acquire the voltage signal across the sampling resistor, amplify the signal, and transmit it to the analog-to-digital converter for processing to obtain the load current. However, sampling small currents in the milliampere range using a sampling resistor with a large resistance (e.g., ohms to hundreds of ohms) ensures high accuracy for small currents, but sampling large currents in the ampere range leads to lower thermal efficiency and a larger footprint on the printed circuit board (PCB), posing a risk of thermal failure. Sampling small currents in the milliampere range using a sampling resistor with a small resistance (e.g., milliohms) requires amplifying the input from the microvolt (μV) level to the millivolt (mV) level. At this amplification factor of thousands of times, the sampling error is significant, resulting in lower sampling accuracy.

[0003] The inventors of this application discovered during research and practice that, in order to meet a wide range of sampling requirements, relays or field-effect transistors (MOSFETs, or MOS) are typically used to switch between different sampling resistors (such as sampling resistor 1 and sampling resistor 2) for sampling. Figure 2As shown, by switching the power circuit to different sizes of sampling resistors using relays or MOSFETs, high-precision sampling over a wide current sampling range can be achieved. However, due to the on-resistance of the MOSFET and the contact resistance of the relay, the output efficiency will decrease, the sampling circuit size will increase, and additional thermal failure risks will be introduced. Summary of the Invention

[0004] This application provides a current sampling circuit and an RF power supply, which can realize wide-range, high-precision current detection and has high applicability.

[0005] In a first aspect, this application provides a current sampling circuit, which includes a first sampling resistor, a second sampling resistor, a sampling power supply, and a current sampling control unit. A first terminal of the first sampling resistor is connected to the power supply, and a second terminal of the first sampling resistor is connected to a load. A first terminal of the second sampling resistor is connected to the voltage output terminal of the sampling power supply, and a second terminal of the second sampling resistor is connected to the load. The current sampling control unit is connected to the first sampling resistor, the second sampling resistor, and the sampling power supply. Here, under a first operating condition, the current sampling control unit can control the sampling power supply to increase its output voltage until it detects a reversal in the current direction of the first sampling current flowing through the first sampling resistor. When the current direction reverses, it acquires the second sampling current flowing through the second sampling resistor as the load current output. Under the first operating condition, the magnitude of the first sampling current is less than a current sampling threshold. Under a second operating condition, the current sampling control unit can also acquire the first sampling current as the load current output. Under the second operating condition, the magnitude of the first sampling current is greater than the current sampling threshold. In this application, under the first operating condition, the current sampling control unit can control the sampling power supply to increase the output voltage, thereby reversing the direction of the sampling current flowing through the first sampling resistor (for ease of description, the sampling current flowing through the first sampling resistor will be described using the first sampling current as an example below). At this time, only the sampling current flowing through the second sampling resistor (for ease of description, the sampling current flowing through the second sampling resistor will be described using the second sampling current as an example below) flows through the load, allowing current sampling of the second sampling resistor to achieve current sampling of small load currents. Under the second operating condition, the current sampling control unit samples the current through the first sampling resistor to achieve current sampling of large load currents. In other words, for small current sampling of the load, the current flowing through the second sampling resistor can be sampled, and the sampled second sampling current flowing through the second sampling resistor can be used as the load current output, ensuring the output efficiency of the power supply and achieving circuit miniaturization. For large current sampling, the current flowing through the first sampling resistor can be directly sampled, and the sampled first sampling current flowing through the first sampling resistor can be used as the load current output, improving current sampling efficiency, simplifying operation, and increasing applicability. By switching the sampling current flowing through different sampling resistors, large current sampling and small current sampling of the load can be achieved under different operating conditions. This can increase the sampling range of the load current, improve the sampling accuracy of the load current, and the circuit structure is simple, the hardware cost is low, and the applicability is strong.

[0006] In one possible implementation of the first aspect, the aforementioned current sampling control unit includes an integrating circuit, a first control unit, and a current sampling unit. The first input terminal of the integrating circuit is connected to the first terminal of the first sampling resistor, the second input terminal of the integrating circuit is connected to the second terminal of the first sampling resistor, the output terminal of the integrating circuit is connected to the first control unit, and the current sampling unit is connected to the first sampling resistor and the second sampling resistor. Specifically, the first control unit can control the sampling power supply to increase its output voltage under a first operating condition to adjust the voltage difference across the first sampling resistor. When the integrating circuit detects that the voltage difference across the first sampling resistor is 0 under the first operating condition, it outputs a current reversal signal to the first control unit. This current reversal signal indicates that the current direction of the first sampling current flowing through the first sampling resistor has reversed. Upon receiving the current reversal signal, the first control unit can also control the sampling power supply to stop increasing its output voltage and trigger the current sampling unit to collect the first sampling current as the load current. In this application, by controlling the sampling power supply to increase its output voltage through the first control unit, the current direction of the first sampling current can be reversed. The integrating circuit can continuously collect the voltage difference across the first sampling resistor. Therefore, when the voltage difference across the first sampling resistor is detected to be 0, it can be determined that the current direction of the first sampling current has reversed. At the instant the current direction of the first sampling current reverses, only the second sampling current flows through the load. At this moment, the current sampling unit can sample the second sampling resistor to obtain the load current. It can be seen that the first control unit can switch the current sampling from the first sampling resistor to the second sampling resistor. The integrator circuit can collect the voltage difference across the first sampling resistor in real time. When the voltage difference across the first sampling resistor is 0, the first control unit triggers the current sampling unit to collect the second sampling current, thus achieving current sampling of small load currents. Furthermore, sampling small load currents through a small current sampling resistor can improve power supply thermal efficiency while maintaining a certain sampling accuracy. Also, the small current sampling resistor has a small area, thus improving PCB board utilization.

[0007] In one possible implementation of the first aspect, the aforementioned current sampling control unit includes an integrating circuit and a current sampling unit. The first input terminal of the integrating circuit is connected to the first terminal of the first sampling resistor, the second input terminal of the integrating circuit is connected to the second terminal of the first sampling resistor, the output terminal of the integrating circuit is connected to the output voltage control terminal of the sampling power supply, and the current sampling unit is connected to the first sampling resistor and the second sampling resistor. Specifically, under a first operating condition, the integrating circuit can output a current detection signal to the sampling power supply based on the voltage difference across the first sampling resistor, triggering the sampling power supply to increase its output voltage based on the current detection signal. Furthermore, when the voltage difference across the first sampling resistor is zero, the integrating circuit can output a current reversal signal to the sampling power supply. This current reversal signal indicates that the direction of the first sampling current flowing through the first sampling resistor has reversed, triggering the sampling power supply to stop increasing its output voltage and triggering the current sampling unit to acquire the second sampling current as the load current. In this application, under the first operating condition, the integrating circuit can continuously acquire the voltage signal across the first sampling resistor (used to characterize the voltage difference across the first sampling resistor), and after processing the voltage signal, output a current detection signal to the sampling power supply to trigger the sampling power supply to increase the output voltage until the current direction of the first sampling current reverses. At this time, the integrating circuit can output a current reversal signal to the current sampling unit to trigger the current sampling unit to sample the current of the second sampling resistor and obtain the load current. It can be seen that the integrating circuit can trigger the current sampling unit to switch from sampling the current of R1 to sampling the current of R2 to obtain the load current. In addition, using a small current sampling resistor to achieve current sampling of a small load current ensures a certain sampling accuracy and can also improve the thermal efficiency of the power supply. Moreover, the small current sampling resistor area and the number of circuit components included in the current sampling control unit are small, which can improve the utilization rate of the PCB board.

[0008] In one possible implementation of the first aspect, the integrator circuit includes a first operational amplifier (OPA), a first resistor, and a capacitor. The non-inverting input of the first OPA serves as the first input of the integrator circuit, the inverting input serves as the second input, and the output serves as the output. The first resistor and capacitor are connected in series between the output and inverting input of the first OPA. The first OPA can acquire the voltage difference across the first sampling resistor and output a current detection signal or a current inversion signal. In this application, the first resistor and capacitor can jointly form a feedback network. This feedback network can return a portion of the output signal of the first OPA to the inverting input of the first OPA to achieve negative feedback of the output signal. Simultaneously, the capacitor can achieve a filtering effect. It is understood that the feedback network composed of the first resistor and capacitor can improve the stability of the gain, maintain a linear relationship between the output signal and the input voltage signal of the integrator circuit, thereby improving the reliability and accuracy of the integrator circuit. Furthermore, the voltage signal can be filtered by configuring the network parameters to reduce noise interference. The circuit structure is simple and highly adaptable.

[0009] In one possible implementation of the first aspect, the current sampling unit includes a first operational amplifier circuit, a second operational amplifier circuit, and a second control unit. The first input terminal of the first operational amplifier circuit is connected to the first terminal of the first sampling resistor, the second input terminal of the first operational amplifier circuit is connected to the second terminal of the first sampling resistor, and the output terminal of the first operational amplifier circuit is connected to the second control unit. The first input terminal of the second operational amplifier circuit is connected to the first terminal of the second sampling resistor, the second input terminal of the second operational amplifier circuit is connected to the second terminal of the second sampling resistor, and the output terminal of the second operational amplifier circuit is connected to the second control unit. Specifically, the first operational amplifier circuit can acquire the voltage signal across the first sampling resistor and output a first voltage sampling signal to the second control unit; the second operational amplifier circuit can acquire the voltage signal across the second sampling resistor and output a second voltage sampling signal to the second control unit; the second control unit can obtain the magnitude of the second sampled current based on the second voltage sampling signal under a first operating condition, and output the magnitude of the second sampled current as the magnitude of the load current when a current reversal signal is received; under a second operating condition, it can obtain the magnitude of the first sampled current based on the first voltage sampling signal, and output the magnitude of the first sampled current as the magnitude of the load current when a current reversal signal is received. In this application, under the first operating condition, the magnitude of the first sampling current is less than the current sampling threshold. In this case, the second operational amplifier circuit can sample the current of the second sampling resistor and calculate the current magnitude of the current based on the sampled second sampling voltage signal. This ensures that at least a small current sampling resistor (i.e., the second sampling resistor) is used as the sampling resistor under the first operating condition. Therefore, sampling the small current sampling resistor enables current sampling of small load currents. Under the second operating condition, the magnitude of the first sampling current is greater than the current sampling threshold. In this case, the first operational amplifier circuit can sample the current of the first sampling resistor and calculate the current magnitude of the current based on the sampled first sampling voltage signal. This ensures that at least a large current sampling resistor (i.e., the first sampling resistor) is used as the sampling resistor under the second operating condition. Therefore, sampling the large current sampling resistor enables current sampling of large load currents, achieving a wide range of load current detection and strong applicability.

[0010] In one possible implementation of the first aspect, the second control unit may further control the sampling power supply to increase the output voltage during the current sampling calibration phase when the load is empty, until the current direction of the first sampling current flowing through the first sampling resistor reverses, and acquire the current flowing through the second sampling resistor as the calibration current when the current direction reverses. Further, the second control unit may also obtain the bias voltage of the first operational amplifier based on the calibration current and the resistance value of the first sampling resistor, and correct the first sampling current or the second sampling current based on the bias voltage and the resistance value of the first sampling resistor to obtain the corrected load current magnitude output. In this application, the integrator circuit can be calibrated before sampling the load current, which can improve the sampling accuracy of the load current, is simple to operate, and has strong applicability.

[0011] In one possible implementation of the first aspect, the first operational amplifier circuit includes a second operational amplifier, a third operational amplifier, a fourth operational amplifier, a second resistor, a third resistor, a fourth resistor, and a fifth resistor. The non-inverting input of the second operational amplifier serves as the first input of the first operational amplifier circuit. The output of the second operational amplifier is connected to the inverting input of the second operational amplifier and connected to the inverting input of the third operational amplifier via the second resistor. The non-inverting input of the fourth operational amplifier serves as the second input of the first operational amplifier circuit. The output of the fourth operational amplifier is connected to the inverting input of the fourth operational amplifier and connected to the non-inverting input of the third operational amplifier via the third resistor. The fourth resistor is connected between the non-inverting input of the third operational amplifier and ground. The fifth resistor is connected between the output of the third operational amplifier and the inverting input of the third operational amplifier. The second and fourth operational amplifiers can acquire the voltage signal across the first sampling resistor and output a first differential signal to the third operational amplifier. The third operational amplifier can amplify the first differential signal to obtain a first voltage sampling signal and output the first voltage sampling signal to the second control unit. In this application, the voltage signal across the first sampling resistor can be acquired by the second and fourth operational amplifiers, and the voltage difference across the first sampling resistor can be differentially amplified by the third operational amplifier. This can effectively suppress the common-mode rejection ratio, improve the detection sensitivity of small signals, and thus improve the sampling accuracy of the first sampling current.

[0012] In one possible implementation of the first aspect, the second operational amplifier circuit includes a fifth operational amplifier, a sixth operational amplifier, a seventh operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor. The non-inverting input of the fifth operational amplifier serves as the first input of the second operational amplifier circuit. The output of the fifth operational amplifier is connected to its inverting input and then connected to the inverting input of the sixth operational amplifier via the sixth resistor. The non-inverting input of the seventh operational amplifier serves as the second input of the second operational amplifier circuit. The output of the seventh operational amplifier is connected to its inverting input and then connected to the non-inverting input of the sixth operational amplifier via the seventh resistor. The eighth resistor is connected between the non-inverting input of the sixth operational amplifier and ground. The ninth resistor is connected between the output of the sixth operational amplifier and its inverting input. The fifth and seventh operational amplifiers can acquire the voltage signal across the second sampling resistor and output a second differential signal to the sixth operational amplifier. The sixth operational amplifier amplifies the second differential signal to obtain a second voltage sampling signal and outputs the second voltage sampling signal to the second control unit. In this application, the voltage signal across the second sampling resistor can be acquired through the fifth and seventh operational amplifiers, and the voltage difference across the second sampling resistor can be differentially amplified through the sixth operational amplifier. This can effectively suppress the common-mode rejection ratio, improve the detection sensitivity of small signals, and thus improve the sampling accuracy of the second sampling current.

[0013] In one possible implementation of the first aspect, the first control unit may include an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC). The ADC may be connected to the output voltage control terminal of the sampling power supply, and the output terminal of the integrator circuit may be connected to the ADC in the first control unit. The ADC can control the sampling power supply to increase its output voltage to adjust the voltage difference across the first sampling resistor. The ADC can output a voltage control signal to the ADC upon receiving a current inversion signal. The ADC can also control the sampling power supply to stop increasing its output voltage upon receiving the voltage control signal, thereby stopping the adjustment of the voltage difference across the first sampling resistor. In this application, the ADC in the first control unit enables precise measurement when sampling the second sampling current, improving the accuracy of sampling small currents. This allows the current sampling unit to be triggered to sample the second sampling resistor when the voltage difference across the first sampling resistor is detected to be 0, thereby achieving current sampling of small load currents, increasing the sampling range of the load current, and enhancing applicability. Secondly, this application provides a radio frequency (RF) power supply, which includes a power supply and the current sampling circuit provided in the first aspect. In this application, based on the coordinated operation of the power supply and the current sampling circuit, it is applicable to achieving a wide range of load current detection. It can sample load currents of different magnitudes under different operating conditions, covering a wider range of current detection, while also offering high detection accuracy, strong flexibility, and high applicability. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of an application scenario for resistor-based current sampling;

[0015] Figure 2 This is a schematic diagram of another application scenario for resistor sampling current;

[0016] Figure 3 This is a schematic diagram of the current sampling circuit provided in this application;

[0017] Figure 4 This is another schematic diagram of the current sampling circuit provided in this application;

[0018] Figure 5 This is another schematic diagram of the current sampling circuit provided in this application;

[0019] Figure 6 This is another schematic diagram of the current sampling circuit provided in this application;

[0020] Figure 7 This is another schematic diagram of the current sampling circuit provided in this application;

[0021] Figure 8 This is another schematic diagram of the current sampling circuit provided in this application. Detailed Implementation

[0022] The current sampling circuit provided in this application is applicable to realizing a wide range of load current detection. Through the current sampling control unit, the current sampling of the first sampling resistor can be switched to the current sampling of the second sampling resistor, so as to realize the sampling of load current of different magnitudes under different operating conditions.

[0023] See Figure 3 , Figure 3 This is a schematic diagram of the current sampling circuit provided in this application. Figure 3 As shown, the current sampling circuit may include a first sampling resistor, a second sampling resistor, a sampling power supply, and a current sampling control unit. The first terminal of the first sampling resistor is connected to the power supply, and the second terminal is connected to the load. The first terminal of the second sampling resistor is connected to the voltage output terminal of the sampling power supply, and the second terminal is connected to the load. The current sampling control unit is connected to the first sampling resistor, the second sampling resistor, and the sampling power supply.

[0024] The current sampling control unit can acquire the voltage signal across the sampling resistor, and calculate the current flowing through the sampling resistor from the voltage signal. Therefore, the power supply can supply power to the load through the first sampling resistor, causing a voltage drop across it, resulting in a voltage difference across the first sampling resistor. The current flowing through the first sampling resistor at this time can be recorded as the first sampling current, with a magnitude of I1. Similarly, the sampling power supply can supply power to the load through the second sampling resistor, causing a voltage drop across it, resulting in a voltage difference across the second sampling resistor. The current flowing through the second sampling resistor at this time can be recorded as the second sampling current, with a magnitude of I2. The first sampling resistor is the larger of the first and second sampling resistors (which can be called the high-current sampling resistor), and current sampling through the first sampling resistor is called high-current sampling. The second sampling resistor is the smaller of the first and second sampling resistors (which can be called the low-current sampling resistor), and current sampling through the second sampling resistor is called low-current sampling. It should be understood that the resistance values ​​of the first and second sampling resistors can be determined based on the operating current of the load, and can be specifically determined according to the actual application scenario; this application does not impose any restrictions here.

[0025] Here, the selection of the first and second sampling resistors includes, but is not limited to, carbon film resistors, metal film resistors, wire-wound resistors, metal oxide film resistors, surface mount resistors, etc. The specific selection can be determined according to the actual application scenario, and there are no restrictions here.

[0026] Please see again. Figure 3 When the load operates in the first condition (such as sleep or low-power mode), the magnitude of the first sampled current is less than the current sampling threshold, and only a tiny current (such as milliampere-level current) flows through the load (for ease of description, the current flowing through the load is called the load current, denoted as I). Load In this case, for small current sampling of the load, the current flowing through the small current sampling resistor can be sampled. That is, the current flowing through the second sampling resistor is sampled by the current sampling control unit, and the sampled second sampling current is output as the load current, thereby realizing current sampling of the small load current. When the load is working in the second operating condition (such as full load mode), the magnitude of the first sampling current is greater than the current sampling threshold, and the load current flowing through the load is larger (such as an ampere-level current). In this case, for large current sampling of the load, the current flowing through the large current sampling resistor can be sampled. That is, the current flowing through the first sampling resistor is sampled by the current sampling control unit, and the sampled first sampling current is output as the load current, thereby realizing current sampling of the large load current. The above-mentioned current sampling threshold can be any suitable current value, which can be set as needed, and this application does not limit it. For example, the threshold can be 5mA.

[0027] As can be seen, by using a two-stage sampling resistor, the load current range can be divided into two levels. In the first operating condition, the current sampling control unit samples a small current from the second sampling resistor and outputs this sampled current as the load current, ensuring power supply output efficiency and achieving circuit miniaturization. In the second operating condition, the current sampling control unit samples a large current from the first sampling resistor and outputs this sampled current as the load current, improving current sampling accuracy. By switching between sampling currents from different sampling resistors, large and small current sampling of the load can be achieved under different operating conditions, increasing the load current sampling range and improving sampling accuracy.

[0028] In some feasible implementations, such as Figure 3 As shown, the current sampling control unit can, under a first operating condition, control the sampling power supply to increase the output voltage until it detects a reversal in the current direction of the first sampling current flowing through the first sampling resistor. When the current direction reverses, it acquires the second sampling current flowing through the second sampling resistor as the load current output. In the first operating condition, the magnitude of the first sampling current is less than the current sampling threshold. The current sampling control unit can also acquire the first sampling current as the load current output under a second operating condition, where the magnitude of the first sampling current is greater than the current sampling threshold in the first operating condition.

[0029] In the first operating condition, when the sampling power supply powers the load through the second sampling resistor, and the power supply powers the load through the first sampling resistor, and the output voltage of the sampling power supply is relatively small, causing the voltage supplied by the sampling power supply to the load to be less than the voltage supplied by the power supply, the direction of the first sampling current flowing through the first sampling resistor is from left to right, that is, from the first terminal of the first sampling resistor to the second terminal. The voltage at the first terminal of the first sampling resistor can be denoted as Va, and the voltage at the second terminal can be denoted as Vb, where Va > Vb. The direction of the second sampling current is from top to bottom, that is, from the first terminal of the second sampling resistor to the second terminal. The voltage at the first terminal of the second sampling resistor can be denoted as Vc. Since both the first and second terminals of the second sampling resistor are connected to the load, the voltage at the second terminal of the second sampling resistor is the same as the voltage at the second terminal of the first sampling resistor, both being Vb. It should be understood that, since the direction of the second sampling current is from top to bottom, Vc > Vb.

[0030] When the current sampling control unit controls the sampling power supply to increase the output voltage, the voltage across the second sampling resistor increases, i.e., Vc and Vb increase. When Vb = Va, the magnitude of the first sampling current I1 is 0. If the current sampling control unit continues to control the sampling power supply to increase the output voltage, the direction of the first sampling current flowing through the first sampling resistor will reverse. When the magnitude of the first sampling current I1 is 0, only the second sampling current flows through the load. Therefore, current sampling can be performed on the second sampling resistor to achieve current sampling of small load currents. At this time, I... Load =I2.

[0031] In the second operating condition, for example, when the power supply is operating at full load, its primary function is to provide power to the load. Although the sampling power supply can also provide power to the load, the second sampling current is in the milliampere range, while the first sampling current is in the ampere range. Therefore, the second sampling current can be ignored, and current sampling can be performed on the first sampling resistor to achieve current sampling of the large load current, i.e., I. Load =I1.

[0032] It should be understood that in the first operating condition, the magnitude of the first sampling current is less than the current sampling threshold. The current sampling control unit can control the sampling power supply to increase the output voltage, causing the current direction of the first sampling current to reverse. At the instant the current direction of the first sampling current reverses, only the second sampling current flows through the load. At this time, current sampling can be performed on the second sampling resistor to achieve current sampling of small load currents. In the second operating condition, the magnitude of the first sampling current is greater than the current sampling threshold. The current sampling control unit can perform current sampling on the first sampling resistor to achieve current sampling of large load currents. Therefore, the current sampling control unit can collect sampling currents flowing through different sampling resistors, thereby achieving large and small current sampling of the load under different operating conditions. This increases the range of sampling currents (e.g., microampere and ampere levels) and ensures relatively high current sampling accuracy over a wide current sampling range. The circuit structure is simple, the hardware cost is low, and the applicability is strong.

[0033] In some feasible implementations, see Figure 4 , Figure 4 This is another schematic diagram of the current sampling circuit provided in this application. (See diagram below.) Figure 4 As shown, the current sampling control unit includes an integrating circuit, a first control unit, and a current sampling unit; the first input terminal of the integrating circuit is connected to the first terminal of the first sampling resistor R1, the second input terminal of the integrating circuit is connected to the second terminal of R1, the output terminal of the integrating circuit is connected to the first control unit, and the current sampling unit is connected to R1 and the second sampling resistor R2.

[0034] The first control unit can, under the first operating condition, control the sampling power supply to increase the output voltage to adjust the voltage difference across R1. The first control unit's control of the sampling power supply's output voltage increase can be seen as increasing the voltage at the second terminal Vb of R1. The integrating circuit can, under the first operating condition, detect when the voltage difference across R1 is 0 and output a current reversal signal to the first control unit. This current reversal signal indicates that the direction of the first sampling current flowing through R1 has reversed. Here, the integrating circuit can sample the voltage difference across R1; when the voltage difference across R1 is 0, i.e., Vb = Va, it can output a current reversal signal to the first control unit. Upon receiving the current reversal signal, the first control unit can also control the sampling power supply to stop increasing the output voltage and trigger the current sampling unit to sample the second sampling current as the load current output.

[0035] It should be understood that by controlling the sampling power supply to increase the output voltage through the first control unit, the current direction of the first sampling current can be reversed. The voltage signal across R1 (i.e., the voltage difference across R1) can be continuously acquired through the integrating circuit. When the voltage difference across R1 is detected to be 0, it can be determined that the current direction of the first sampling current is about to reverse. At the instant the current direction of the first sampling current reverses, only the second sampling current flows through the load. At this time, the current sampling unit can sample the current of R2 to obtain the load current. Therefore, the first control unit can switch the current sampling of R1 to the current sampling of R2. The integrating circuit can acquire the voltage difference across R1 in real time. When the voltage difference across R1 is 0, a signal indicating a 0 voltage difference across R1 can be output to the first control unit as a current reversal signal. The first control unit controls the sampling power supply to stop increasing the output voltage and simultaneously triggers the current sampling unit to acquire the second sampling current, thus achieving current sampling of a small load current. In addition, sampling the current of a small load by using a small current sampling resistor can improve the thermal efficiency of the power supply while ensuring a certain sampling accuracy. Moreover, the small current sampling resistor has a small area, which can improve the utilization rate of the PCB board.

[0036] Furthermore, in some feasible implementations, see [link to relevant documentation]. Figure 5 , Figure 5 This is another schematic diagram of the current sampling circuit provided in this application. (See diagram below.) Figure 5 As shown, the first control unit may include an ADC and a DAC. The DAC can be connected to the output voltage control terminal of the sampling power supply, and the output terminal of the integrator circuit can be connected to the ADC in the first control unit. The DAC can control the sampling power supply to increase the output voltage to adjust the voltage difference across R1. The ADC can output a voltage control signal to the DAC when it receives a current inversion signal. The DAC can control the sampling power supply to stop increasing the output voltage when it receives the voltage control signal, thereby stopping the adjustment of the voltage difference across R1. Optionally, the ADC can use an STM32 microcontroller chip. In this case, the integrator circuit can be connected to the STM32 microcontroller chip and the corresponding I / O port of the ADC.

[0037] In some feasible implementations, the output voltage control terminal of the sampling power supply can be a trim pin. In this case, the DAC can control the sampling power supply to boost the output voltage through the trim pin. Optionally, the output voltage of the sampling power supply can be adjusted by changing the voltage division ratio of the output voltage feedback loop. For example, a resistor can be connected in parallel between the trim pin and ground to change the voltage division ratio of the voltage feedback loop, thereby reducing the impedance of the voltage feedback loop and thus increasing the output voltage of the sampling power supply.

[0038] In some feasible implementations, the ADC can continuously receive the integral signal output by the integrator circuit. This integral signal is generated by the integrator circuit processing the voltage signal across R1, where the voltage signal can be the voltage difference across R1. The ADC can detect whether it has received a current-flipping signal transmitted by the integrator circuit based on the processing result of the analog signal (here, the integral signal). For example, the ADC can quantize the received integral signal, convert it into an ADC code value (i.e., a digital signal), and determine whether a current-flipping signal has been received based on the ADC code value. Optionally, when the digital level of the integral signal processed by the ADC changes from high to low, or from low to high, or from an initial value (which can be considered as the output voltage of the sampling power supply not yet being increased) towards a target value, it can be determined that a current-flipping signal has been received. The specific determination can be based on the actual application scenario and is not limited here. The target value can be preset.

[0039] For example, the actual voltage value of the integrated signal can be obtained based on the ADC code value of the ADC output, the reference voltage, and the ADC resolution. The reference voltage is preset and should be within the operating range of the ADC. The specific formula is as follows:

[0040] Actual voltage value = ADC code value * (reference voltage / ADC resolution) (1)

[0041] For example, if the ADC resolution is 10 bits and the reference voltage is 5V, the ADC can divide the reference voltage into 2... 10 Each part is 1 / 1024 of the reference voltage. If the ADC code value read by the ADC is 820, then by substituting into formula (1), the actual voltage value of the integrated signal can be obtained as 4.0003V.

[0042] Therefore, the ADC can be used to obtain the actual voltage value of the integrated signal. In other words, the ADC can be used to obtain the voltage difference across R1, and then it can be used to detect whether the voltage difference across R1 is 0. When the voltage difference across R1 is 0, it can be determined that the integrated signal received by the ADC is a current inversion signal. At this time, the ADC can output a voltage control signal to the DAC so that the DAC controls the sampling power supply to stop increasing the output voltage.

[0043] In some feasible implementations, such as Figure 5As shown, the first control unit may further include a microcontroller unit (MCU). The MCU can be connected to the ADC, DAC, and current sampling unit, and can be used to control or trigger the operation of the ADC, DAC, and current sampling unit. It can also store the operating parameters of the ADC (such as the current switching signal mentioned above). In some embodiments, the MCU may use an ARM Cortex-M4 core, which can be determined according to the actual application scenario and is not limited here.

[0044] In practice, the ADC can sample and quantize the integral signal and feed it back to the MCU. Based on the ADC's processing result of the integral signal, the MCU detects whether the ADC has received a current inversion signal. When the ADC receives a current inversion signal, the MCU outputs a voltage control signal to the DAC. When the ADC receives a current inversion signal, the MCU can trigger the current sampling unit to sample the current of R2.

[0045] Optionally, the aforementioned MCU can be replaced with a controllable programmable control unit (FPGA). The FPGA can be connected to the ADC, DAC, and current sampling unit, and can be used to control or trigger the operation of the ADC, DAC, and current sampling unit. It can also store the ADC's processing results of the integral signal. Here, the FPGA can be a field-programmable gate array (FPGA) or other types of circuit controllers, depending on the specific application scenario; no restrictions are imposed here.

[0046] Optionally, wireless communication can also be used for signal interaction between the ADC and DAC. The specific method can be determined according to the actual application scenario, and this application does not impose any restrictions.

[0047] In some feasible implementations, the DAC can be external to the first control unit, in which case the first control unit is an ADC, i.e., the current sampling control unit includes an integrating circuit, an ADC, and a current sampling unit. The specific structure of the first control unit can be determined according to the actual application scenario, and this application does not limit it. In this embodiment, the first control unit can be connected to the output voltage control terminal of the sampling power supply through the DAC to control the sampling power supply to boost the output voltage.

[0048] It is understandable that the ADC in the first control unit can accurately measure the small load current when sampling, which improves the accuracy of sampling small currents. This allows the current sampling unit to be triggered to sample the current of R2 when the voltage difference across R1 is 0, thereby realizing current sampling of small load currents, improving the sampling range of load currents, and making it highly applicable.

[0049] In some feasible implementations, such as Figure 5 As shown, the current sampling unit includes a first operational amplifier circuit, a second operational amplifier circuit, and a second control unit. The first input terminal of the first operational amplifier circuit is connected to the first terminal of resistor R1, the second input terminal of the first operational amplifier circuit is connected to the second terminal of R1, and the output terminal of the first operational amplifier circuit is connected to the second control unit. The first input terminal of the second operational amplifier circuit is connected to the first terminal of resistor R2, the second input terminal of the second operational amplifier circuit is connected to the second terminal of R2, and the output terminal of the second operational amplifier circuit is connected to the second control unit. The first operational amplifier circuit can acquire the voltage signal across resistor R1 and output a first voltage sampling signal to the second control unit. The second operational amplifier circuit can acquire the voltage signal across resistor R2 and output a second voltage sampling signal to the second control unit. Under the first operating condition, the second control unit can obtain the magnitude of the second sampled current based on the second voltage sampling signal, and upon receiving a current reversal signal, output the magnitude of the second sampled current as the magnitude of the load current. Under the second operating condition, the second control unit can obtain the magnitude of the first sampled current based on the first voltage sampling signal, and upon receiving a current reversal signal, output the magnitude of the first sampled current as the magnitude of the load current.

[0050] In specific implementation, the first operational amplifier circuit can continuously acquire the voltage signal across R1, amplify the voltage signal across R1, and output a first voltage sampling signal to the second control unit. The amplification factor can be a first amplification factor. The second operational amplifier circuit can continuously acquire the voltage signal across R2, amplify the voltage signal across R2, and output a second voltage sampling signal to the second control unit. The amplification factor can be a second amplification factor. The magnitudes of the first and second factors can be the same or different, and can be determined according to the actual application scenario. This application does not impose any restrictions here. The second control unit can process the first voltage sampling signal to obtain the magnitude of the first sampling current, and the second control unit can process the second voltage sampling signal to obtain the magnitude of the second sampling current.

[0051] Here, the second control unit can also store the calculated magnitude of the first sampled current and the magnitude of the second sampled current. Under the first operating condition, when the second control unit receives the current reversal signal, it can output the stored magnitude of the second sampled current as the magnitude of the load current. Under the second operating condition, when the second control unit receives the current reversal signal, it can output the magnitude of the first sampled current as the magnitude of the load current.

[0052] Furthermore, in some feasible implementations, the second control unit may include an ADC (Analog-to-Digital Converter). The ADC can perform analog-to-digital conversion on the first voltage sampling signal, that is, convert the first voltage sampling signal into ADC code values ​​(digital signals), and calculate the current value of the first sampling current based on the ADC code values. Similarly, the ADC can perform analog-to-digital conversion on the second voltage sampling signal, that is, convert the second voltage sampling signal into ADC code values, and calculate the current value of the second sampling current based on the ADC code values. The second control unit may be one ADC conversion channel in an ADC chip that includes multiple ADC conversion channels, or it may be an ADC chip with a single ADC conversion channel. Since the input voltage range of the ADC chip is fixed, and its optimal linearity range is slightly smaller than the conventional range, in order to ensure current sampling accuracy, the voltage values ​​of the first and second voltage sampling signals should be within the preset accuracy range of the ADC conversion channel.

[0053] The current value calculated based on the ADC code value can be done by the ADC itself, or it can be sent by the ADC to other units (such as MCU or FPGA chips). The specific method can be determined according to the actual application scenario, and this application does not impose any restrictions.

[0054] In some feasible implementations, if the first control unit only includes the ADC, the first control unit and the second control unit can be the same control unit. In other words, the second control unit can also control the sampling power supply to increase the output voltage under the first operating condition to adjust the voltage difference across R1, and is also used to control the sampling power supply to stop increasing the output voltage and collect the second sampling current as the load current output when a current inversion signal is received.

[0055] In some feasible implementations, the current sampling unit can sample the current of R1 or R2 and output the first sampled current or the second sampled current as the load current. The current sampling unit includes, but is not limited to, a series resistor sampling circuit, a current mirror sampling circuit, an inductor-DC resistance (DCR) current sampling circuit, a field-effect transistor current sampling circuit, or a Hall effect sampling circuit. The specific method can be determined according to the actual application scenario and is not limited here. Optionally, in some feasible implementations, a current sensor can be used instead of the current sampling unit to achieve current sampling. The specific method can be determined according to the actual application scenario and is not limited here.

[0056] In this embodiment, under the first operating condition, when the magnitude of the first sampling current is less than the current sampling threshold, the second operational amplifier circuit samples the current of R2 and calculates the magnitude of the current ...

[0057] In some feasible implementations, see Figure 6 , Figure 6 This is another schematic diagram of the current sampling circuit provided in this application. (See diagram below.) Figure 6 As shown, the first operational amplifier circuit includes OPA2, OPA3, OPA4, a second resistor R4, a third resistor R5, a fourth resistor R6, and a fifth resistor R7. The non-inverting input of OPA2 serves as the first input of the first operational amplifier circuit. The output of OPA2 is connected to the inverting input of OPA2 and then connected to the inverting input of OPA3 via R4. The non-inverting input of OPA4 serves as the second input of the first operational amplifier circuit. The output of OPA4 is connected to the inverting input of OPA4 and then connected to the non-inverting input of OPA3 via R5. R6 is connected between the non-inverting input of OPA3 and ground. R7 is connected between the output of OPA3 and the inverting input of OPA3. OPA2 and OPA4 can acquire the voltage signal across R1 and output a first differential signal to OPA3. OPA3 amplifies the first differential signal to obtain a first voltage sampling signal and outputs the first voltage sampling signal to the second control unit. Here, the output voltage of OPA3 is the first voltage sampling signal, and the amplification factor is the third amplification factor.

[0058] OPA2 can acquire the voltage signal at the second terminal of R1, and OPA4 can acquire the voltage signal at the first terminal of R1. Both OPA2 and OPA4 can output the voltage signal across R1 to OPA3. The voltage signal across R1 is the first differential signal; optionally, the first differential signal can be the voltage difference across R1. Amplifying the voltage signal across R1 by OPA3 can be considered as amplifying the voltage difference across R1. It should be understood that the first voltage sampling signal obtained after amplifying the first differential signal should be within the operating range of the current sampling control unit. The amplification factor can be determined based on the range of the first differential signal and the second control unit; the principle is that the voltage value of the first voltage sampling signal should be slightly lower than the range of the second control unit.

[0059] In this embodiment, as Figure 6 As shown, R4, R5, R6, R7, and OPA3 can form a differential amplifier circuit. OPA3 differentially amplifies the voltage difference across R1 and outputs a differential voltage signal (i.e., the first voltage sampling signal). Differential amplifier circuits can have a high common-mode rejection ratio, which is beneficial for the identification and detection of small signals and improves the detection accuracy of minute currents.

[0060] Optionally, in some feasible implementations, the above-mentioned OPA2 and OPA4 can be voltage followers. Voltage followers have the advantages of high input impedance and low output impedance. Therefore, they can not only isolate the front and rear stage circuits, but also reduce impedance and enhance load capacity, so that the input voltage value of the rear stage circuit (here, OPA3) is equal to the output voltage value of the voltage follower.

[0061] Optionally, protective resistors can be connected to the output terminals of OPA2, OPA3, and OPA4 to protect the op-amp output from short circuits, thereby improving circuit reliability and broadening its applicability.

[0062] It should be understood that, such as Figure 6 The first operational amplifier circuit shown is merely an example. This application does not impose any restrictions on the circuit structure of the first operational amplifier circuit, and the specific structure can be determined according to the actual application scenario.

[0063] In this embodiment, the voltage signal across R1 can be acquired through OPA2 and OPA4, and the voltage difference across R1 can be differentially amplified through OPA3, which can effectively suppress the common-mode rejection ratio, improve the detection sensitivity of small signals, and thus improve the sampling accuracy of the first sampling current.

[0064] In some feasible implementations, see Figure 6The second operational amplifier circuit includes OPA5, OPA6, OPA7, a sixth resistor R8, a seventh resistor R9, an eighth resistor R10, and a ninth resistor R11. The non-inverting input of OPA5 serves as the first input of the second operational amplifier circuit. The output of OPA5 is connected to its inverting input and then to the inverting input of OPA6 via R8. The non-inverting input of OPA7 serves as the second input of the second operational amplifier circuit. The output of OPA7 is connected to its inverting input and then to the non-inverting input of OPA6 via R9. R10 is connected between the non-inverting input of OPA6 and ground. R11 is connected between the output of OPA6 and its inverting input. OPA5 and OPA7 can acquire the voltage signal across R2 and output a second differential signal to OPA6. OPA6 amplifies the second differential signal to obtain a second voltage sampling signal and outputs this second voltage sampling signal to the second control unit. Here, the output voltage of OPA6 is the second voltage sampling signal, and the amplification factor is the fourth amplification factor. Here, the fourth magnification can be the same as or different from the third magnification, and this application does not impose any restrictions on this.

[0065] In specific implementation, OPA5 can acquire the voltage signal at the first terminal of R2, and OPA7 can acquire the voltage signal at the second terminal of R2. Both OPA5 and OPA7 can output the voltage signals across R2 to OPA6. The voltage signal across R2 is the second differential signal; optionally, the second differential signal can be the voltage difference across R2. OPA6 can amplify the voltage difference across R2 and output it as the second voltage sampling signal to the second control unit. It should be understood that the second voltage sampling signal obtained after amplifying the second differential signal should be within the operating range of the current sampling control unit. The amplification factor can be determined based on the range of the second differential signal and the range of the second control unit. The principle is that the voltage value of the second voltage sampling signal should be slightly lower than the range of the second control unit.

[0066] In this embodiment, as Figure 6 As shown, R8, R9, R10, R11, and OPA6 can form a differential amplifier circuit. OPA6 differentially amplifies the voltage difference across R2 and outputs a differential voltage signal. Here, (i.e., the second voltage sampling signal). Differential amplifier circuits can have a high common-mode rejection ratio, which is beneficial for the identification and detection of small signals and improves the detection accuracy of minute currents.

[0067] Optionally, in some feasible implementations, the above-mentioned OPA5 and OPA7 can be voltage followers. Voltage followers have the advantages of high input impedance and low output impedance. Therefore, they can not only isolate the upstream and downstream circuits, but also reduce impedance and enhance load capacity, so that the input voltage value of the downstream circuit (here, OPA6) is equal to the output voltage value of the voltage follower.

[0068] Optionally, protective resistors can be connected to the output terminals of OPA5, OPA6, and OPA7 to protect the op-amp output from short circuits, thereby improving circuit reliability and broadening its applicability.

[0069] It should be understood that, such as Figure 6 The second operational amplifier circuit shown is merely an example. This application does not impose any restrictions on the circuit structure of the second operational amplifier circuit, and the specific structure can be determined according to the actual application scenario.

[0070] In this embodiment, the voltage signal across R2 can be acquired through OPA5 and OPA7, and the voltage difference across R2 can be differentially amplified through OPA6, which can effectively suppress the common-mode rejection ratio, improve the detection sensitivity of small signals, and thus improve the sampling accuracy of the second sampling current.

[0071] Furthermore, in some feasible implementations, see [link to relevant documentation]. Figure 6 The integrating circuit may include OPA1, a first resistor R3, and a capacitor C1. The non-inverting input of OPA1 serves as the first input of the integrating circuit, the inverting input serves as the second input, and the output of OPA1 serves as the output. R3 and C1 are connected in series between the output and the inverting input of OPA1. OPA1 can acquire the voltage difference across R1 and output a current detection signal or a current inversion signal. The selection of R3 includes, but is not limited to, carbon film resistors, metal film resistors, wire-wound resistors, metal oxide film resistors, and surface-mount resistors. The selection of C1 includes, but is not limited to, ceramic capacitors, electrolytic capacitors, film capacitors, and tantalum capacitors.

[0072] like Figure 6 As shown, the output of the integrator circuit is connected to the first control unit. The integrator circuit can continuously acquire the voltage signal across R1 (i.e., the voltage difference across R1), smooth the input signal, eliminate high-frequency noise in the voltage signal, and amplify the voltage signal. Thus, when the output of the integrator circuit is connected to the first control unit, a more stable integrated signal is continuously output to the first control unit so that the first control unit can process the integrated signal.

[0073] Optionally, in some feasible implementations, OPA1 can be an integrating amplifier, and R3 and C1 can jointly form a feedback network. This feedback network can return a portion of the integrating amplifier's output signal (i.e., the integrated signal) to the inverting input of the integrating amplifier to achieve negative feedback of the output signal. Simultaneously, C1 can also achieve a filtering effect. It can be understood that the feedback network composed of R3 and C1 can improve the stability of the gain, maintain a linear relationship between the integrated signal output by the integrating circuit and the input voltage signal, thereby improving the reliability and accuracy of the integrating circuit. Furthermore, by configuring the network parameters, voltage signal filtering can be achieved, reducing noise interference. The circuit structure is simple and highly adaptable.

[0074] In other feasible implementations, the feedback network can also be a parallel feedback network of resistors and capacitors, a series-parallel feedback network of resistors and capacitors, etc., which can be determined according to the actual application scenario, and this application does not impose any restrictions.

[0075] In some feasible implementations, the current sampling circuit can be calibrated before sampling the load current to improve sampling accuracy. The second control unit can also, during the current sampling calibration phase when the load is empty, control the sampling power supply to increase the output voltage until the current direction of the first sampling current flowing through R1 reverses, and acquire the current flowing through R2 as the calibration current when the current direction reverses. Furthermore, the second control unit can obtain the bias voltage of OPA1 based on the calibration current and the resistance value of R1, and correct the first or second sampling current based on the bias voltage and the resistance value of R1 to obtain the corrected load current magnitude output. It can be understood that calibrating the integrator circuit before sampling the load current improves the sampling accuracy of the load current; this method is simple to operate and has strong applicability.

[0076] In some feasible implementations, such as Figure 6 As shown in the integrator circuit, assuming both the non-inverting and inverting inputs of OPA1 are grounded (i.e., V+ = V- = 0), theoretically, the output voltage of OPA1 should also be 0. However, due to the inherent characteristics of OPA1, the output voltage is not actually 0; this voltage is the bias voltage, denoted as Vos, and its unit is typically mV. Since OPA1 is designed with a closed-loop gain of A in the integrator circuit, when the bias voltage Vos is zero and the input of OPA1 is 0, there exists a DC level at the output equal to A * Vos. The larger the closed-loop gain, the larger the output offset voltage, and the greater the error. Therefore, before sampling the load current, OPA1 needs to be calibrated. For example, a DC power supply with the opposite direction to the bias voltage Vos can be connected to the non-inverting input of OPA1 to cancel the bias voltage, thereby improving detection accuracy.

[0077] In some feasible implementations, during the current sampling calibration phase when the load is empty, the second control unit can control the sampling power supply to increase the output voltage. For example, the second control unit can first control the sampling power supply to lower the output voltage until the voltage at the second terminal of R2 is less than the voltage at the second terminal of R1, i.e., Vb < Va. At this time, the current direction of the first sampling current is from left to right. Further, the second control unit can control the sampling power supply to increase the output voltage until the current direction of the first sampling current is about to reverse, at which point Vb = Va.

[0078] Here, when the integrator outputs a current reversal signal to the second control unit, the second control unit can determine that the current direction of the first sampled current is about to reverse, i.e., the magnitude I1 of the first sampled current is 0. When the second control unit includes an ADC, the ADC can continuously receive the integral signal output by the integrator. This integral signal is output by the integrator after processing the voltage signal across R1. Here, the voltage signal can be the voltage difference across R1. The ADC can detect whether it has received the current reversal signal transmitted by the integrator based on the processing result of the analog signal (here, the integral signal). For example, the ADC can quantize the received integral signal and convert it into an ADC code value (i.e., a digital signal), and determine whether it has received the current reversal signal based on the ADC code value. Optionally, when the digital level of the integral signal processed by the ADC changes from high to low, or from low to high, or from the initial value (which can be considered as the output voltage of the sampling power supply not yet being increased) towards the target value, it can be determined that a current reversal signal has been received. The specific determination can be made according to the actual application scenario and is not limited here. The target value can be preset.

[0079] In some feasible implementations, since the second control unit can control the sampling power supply to stop increasing the output voltage when the current direction of the first sampling current is about to reverse, the magnitude of the first sampling current tends to stabilize. Furthermore, because the first operational amplifier circuit can continuously acquire the voltage signal across R1 and continuously output the first voltage sampling signal to the second control unit, the second control unit can calculate and analyze the first voltage sampling signal to obtain the magnitude of the first sampling current. When the second control unit detects that the magnitude of the first sampling current remains within the target detection range for a duration exceeding the target duration, or when the second control unit detects that the magnitude of the first sampling current remains within the target detection range for M consecutive cycles, the second control unit can obtain a current reversal signal indicating that the current direction of the first sampling current is about to reverse. Here, the target detection range and target duration are preset, and M is a positive integer greater than or equal to 2. At this time, the second control unit can use the current of R2 acquired when the current direction of the first sampling current reverses as the calibration current, denoted as I. oIt should be understood that when Vb > Va, that is, the direction of the first sampling current is from right to left, the calibration current flows into the non-inverting input terminal of OPA1 through R1. Due to the presence of the bias voltage, the following formula can be obtained in the circuit composed of R1 and OPA1 based on Kirchhoff's laws:

[0080]

[0081] in, This can represent the calibration current value, and the direction of the calibration current is from the second terminal of R1 to the first terminal of R1. R1 can also represent the resistance value of R1. This can represent the bias voltage value. The positive terminal of the bias voltage is connected to the non-inverting input terminal of OPA1, and the negative terminal is connected to the second terminal of R1. Therefore, the bias voltage can be calculated according to formula (2). Size.

[0082] Furthermore, after the load is connected, under the first operating condition, the output voltage of the sampling power supply increases, causing the current direction of the first sampling current to reverse. When the second control unit receives the current reversal signal, it can sample the current of R2. At this time, the load current can be determined based on the second sampling current, as shown in the following formula:

[0083]

[0084] Among them, I Load The current value can represent the load current. R1 can represent the value of the second sampling current, which flows from the first end of R2 to the second end of R2. R1 can represent the resistance value of R1. It can be determined according to formula (2). Therefore, the load current I can be calculated according to formula (3). Load Size.

[0085] It should be understood that the integrator circuit can be calibrated before sampling the load current to eliminate the influence of the bias voltage, thereby improving the sampling accuracy and making it highly applicable.

[0086] In this embodiment, the output power of the sampling power supply is controlled using open-loop control. An integrator circuit detects the sampling current flowing through R1, while the first control unit controls the sampling power supply to increase its output voltage, causing the current direction of the first sampling current to reverse. When the integrator circuit detects this reversal, it outputs a current reversal signal to the first control unit, causing the first control unit to stop increasing the output voltage. Therefore, the first control unit directly controls whether the sampling power supply increases or stops increasing the output voltage, resulting in fast response and simple operation.

[0087] Optionally, in some feasible implementations, the output power of the sampling power supply can be controlled using closed-loop control, with the output of the integrator circuit connected to the output voltage control terminal of the sampling power supply. See also Figure 7 , Figure 7 This is another schematic diagram of the current sampling circuit provided in this application. (See diagram below.) Figure 7 As shown, the current sampling control unit may include an integrating circuit and a current sampling unit; the first input terminal of the integrating circuit is connected to the first terminal of R1, the second input terminal of the integrating circuit is connected to the second terminal of R1, the output terminal of the integrating circuit is connected to the output voltage control terminal of the sampling power supply, and the current sampling unit is connected to R1 and R2. For details on the structure, working principle, and beneficial effects of the current sampling unit, please refer to [link to relevant documentation]. Figure 6 The corresponding implementation examples will not be described in detail here.

[0088] The integrator circuit can output a current detection signal to the sampling power supply based on the voltage difference across R1 under the first operating condition, and trigger the sampling power supply to increase the output voltage based on the current detection signal. The integrator circuit can also output a current reversal signal to the sampling power supply when the voltage difference across R1 is 0. The current reversal signal is used to indicate that the current direction of the first sampling current flowing through R1 has reversed, triggering the sampling power supply to stop increasing the output voltage and triggering the current sampling unit to obtain the second sampling current as the load current.

[0089] In some feasible implementations, the output voltage control terminal of the sampling power supply can be a trim pin. In this case, the integrating circuit can control the sampling power supply to boost the output voltage through the trim pin. The specific process of the integrating circuit controlling the sampling voltage through the trim pin to adjust the output voltage can be found in the specific process of the DAC controlling the sampling voltage through the trim pin to adjust the output voltage, which will not be elaborated upon here.

[0090] It should be understood that in the first operating condition, the integrating circuit can continuously acquire the voltage signal across R1 (i.e., the voltage difference across R1), process the voltage signal, and output a current detection signal to the sampling power supply to trigger the sampling power supply to increase the output voltage until the current direction of the first sampling current reverses. At this time, the integrating circuit can output a current reversal signal to the current sampling unit to trigger the current sampling unit to sample the current flowing through R2 and obtain the load current. In addition, when the voltage difference across R1 is zero, the integrating circuit can trigger the current sampling unit to acquire the second sampling current to achieve current sampling of a small load current. It can be seen that the integrating circuit can trigger the current sampling unit to switch from current sampling of R1 to current sampling of R2 to obtain the load current. In addition, using a small current sampling resistor to achieve current sampling of a small load current ensures a certain sampling accuracy, improves the thermal efficiency of the power supply, and the small current sampling resistor area and the number of circuit components included in the current sampling control unit can improve the utilization rate of the PCB board.

[0091] Furthermore, in some feasible implementations, see [link to relevant documentation]. Figure 8 , Figure 8 This is another schematic diagram of the current sampling circuit provided in this application. The integrating circuit includes OPA1, R3, and C1; the non-inverting input of OPA1 serves as the first input of the integrating circuit, the inverting input of OPA1 serves as the second input of the integrating circuit, and the output of OPA1 serves as the output of the integrating circuit; R3 and C1 are connected in series between the output of OPA1 and the inverting input of OPA1. OPA1 can acquire the voltage difference across R1 and output a current detection signal or a current inversion signal.

[0092] Among them, the selection of R3 includes, but is not limited to, carbon film resistors, metal film resistors, wire-wound resistors, metal oxide film resistors, surface mount resistors, etc., and the selection of C1 includes, but is not limited to, ceramic capacitors, electrolytic capacitors, film capacitors, tantalum capacitors, etc.

[0093] like Figure 8 As shown, the output of the integrator circuit is connected to the output voltage control terminal of the sampling power supply and the first control unit. The integrator circuit can continuously acquire the voltage signal across R1 (i.e., the voltage difference across R1), smooth the input signal, eliminate high-frequency noise in the voltage signal, and amplify the voltage signal. Thus, when the output of the integrator circuit is connected to the sampling power supply, it continuously outputs a more stable current detection signal to the sampling power supply. The current detection signal can trigger the sampling power supply to increase the output voltage until the current direction of the first sampling current reverses. At the instant the current direction of the first sampling current reverses, a current reversal signal is output to the current sampling unit to trigger the current sampling unit to sample the current of R2.

[0094] Optionally, in some feasible implementations, OPA1 can be an integrating amplifier, and R3 and C1 can jointly form a feedback network. This feedback network can return a portion of the integrating amplifier's output signal (i.e., the integrated signal) to the inverting input of the integrating amplifier to achieve negative feedback of the output signal. Simultaneously, C1 can also achieve a filtering effect. It can be understood that the feedback network composed of R3 and C1 can improve the stability of the gain, maintain a linear relationship between the integrated signal output by the integrating circuit and the input voltage signal, thereby improving the reliability and accuracy of the integrating circuit. Furthermore, by configuring the network parameters, voltage signal filtering can be achieved, reducing noise interference. The circuit structure is simple and highly adaptable.

[0095] In other feasible implementations, the feedback network can also be a parallel feedback network of resistors and capacitors, a series-parallel feedback network of resistors and capacitors, etc., which can be determined according to the actual application scenario, and this application does not impose any restrictions.

[0096] In some feasible implementations, the current sampling circuit can be calibrated before sampling the load current to improve sampling accuracy. When the output of the integrator circuit is connected to the output voltage control terminal of the sampling power supply, the calibration process for the integrator circuit can be found in the section on the calibration process when the first control unit is connected to the output of the integrator circuit; details will not be elaborated upon here.

[0097] In this embodiment, the output power of the sampling power supply can be controlled using closed-loop control. A feedback loop is formed by connecting the output of the integrating circuit to the sampling power supply. This allows the sampling power supply to increase its output voltage when the integrating circuit outputs a current detection signal, thereby adjusting the voltage difference across R1. Conversely, when the integrating circuit outputs a current reversal signal, the sampling power supply can stop increasing its output voltage, keeping the voltage difference across R1 constant. Therefore, the increasing or decreasing of the output voltage is directly controlled by the integrating unit. This allows for precise control of the sampling voltage based on the current detection signal output by the integrating unit, or precise control of the sampling voltage to stop increasing its output voltage based on the current reversal signal output by the integrating unit. This approach offers advantages such as high control precision and strong anti-interference capability.

[0098] This application provides an RF power supply, which includes a power supply and a current sampling circuit. The power supply provides a stable DC input to the current sampling circuit to ensure signal quality and circuit reliability. Here, the power supply includes, but is not limited to, battery packs, uninterruptible power supplies (UPS), DC power modules, etc., depending on the actual application scenario and is not limited here. The power supply may also integrate a power management module for voltage regulation, current limiting, etc., to optimize energy efficiency and system performance. The current sampling circuit can be... Figures 3 to 8 For any of the current sampling circuits shown, the circuit structure and implementation method can be found in the above. Figures 3 to 8 The circuit structure and implementation method provided will not be elaborated here. Here, the current sampling circuit can sample the load current of different magnitudes under different operating conditions by sampling the current through different sampling resistors, thereby achieving a wide range of current sampling and ensuring relatively high current sampling accuracy over a relatively wide current sampling range.

[0099] In this application, the RF power supply, based on the coordinated operation of the power supply and the current sampling circuit, is suitable for realizing a wide range of load current detection. It can sample load currents of different magnitudes under different operating conditions, while having high detection accuracy, strong flexibility, and high applicability.

[0100] It is understood that the terminology used in this application's specification is for the purpose of describing specific embodiments only and is not intended to limit this application. It is understood that the terms "first," "second," etc., used in this application can be used herein to describe various information or data, but these elements are not limited by these terms. These terms are only used to distinguish the first piece of information from another piece of information. In the several embodiments provided in this application, it should be understood that the disclosed circuit structures can be implemented in other ways. For example, the circuit embodiments described above are merely illustrative; for example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or modules, and may be electrical, mechanical, or other forms.

[0101] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical units. Some or all of the modules can be selected to implement the solution of this embodiment, depending on actual needs.

[0102] Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing unit, or each module can exist physically separately, or two or more modules can be integrated into one unit. The unit composed of the above modules can be implemented in hardware or in the form of hardware plus software functional units.

[0103] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A current sampling circuit, characterized in that, The current sampling circuit includes a first sampling resistor, a second sampling resistor, a sampling power supply, and a current sampling control unit; a first terminal of the first sampling resistor is connected to the power supply, and a second terminal of the first sampling resistor is connected to the load; a first terminal of the second sampling resistor is connected to the voltage output terminal of the sampling power supply, and a second terminal of the second sampling resistor is connected to the load; the current sampling control unit is connected to the first sampling resistor, the second sampling resistor, and the sampling power supply. The current sampling control unit is used to control the sampling power supply to increase the output voltage under a first operating condition until the current direction of the first sampling current flowing through the first sampling resistor is detected to be reversed, and to obtain the second sampling current flowing through the second sampling resistor as the load current output when the current direction is reversed, wherein, under the first operating condition, the current magnitude of the first sampling current is less than the current sampling threshold. The current sampling control unit is further configured to acquire the first sampled current as the load current output under a second operating condition, wherein, under the second operating condition, the magnitude of the first sampled current is greater than the current sampling threshold.

2. The current sampling circuit according to claim 1, characterized in that, The current sampling control unit includes an integrating circuit, a first control unit, and a current sampling unit; the first input terminal of the integrating circuit is connected to the first terminal of the first sampling resistor, the second input terminal of the integrating circuit is connected to the second terminal of the first sampling resistor, the output terminal of the integrating circuit is connected to the first control unit, and the current sampling unit is connected to the first sampling resistor and the second sampling resistor; The first control unit is used to control the sampling power supply to increase the output voltage under the first operating condition, so as to adjust the voltage difference across the first sampling resistor; The integrating circuit is used to output a current reversal signal to the first control unit when it detects that the voltage difference across the first sampling resistor is 0 under the first operating condition. The current reversal signal is used to indicate that the current direction of the first sampling current flowing through the first sampling resistor has reversed. The first control unit is further configured to, upon receiving the current reversal signal, control the sampling power supply to stop increasing the output voltage and trigger the current sampling unit to collect the second sampling current as the load current output.

3. The current sampling circuit according to claim 1, characterized in that, The current sampling control unit includes an integrating circuit and a current sampling unit; the first input terminal of the integrating circuit is connected to the first terminal of the first sampling resistor, the second input terminal of the integrating circuit is connected to the second terminal of the first sampling resistor, the output terminal of the integrating circuit is connected to the output voltage control terminal of the sampling power supply, and the current sampling unit is connected to the first sampling resistor and the second sampling resistor; The integrating circuit is used to output a current detection signal to the sampling power supply based on the voltage difference across the first sampling resistor under the first operating condition, and to trigger the sampling power supply to increase the output voltage based on the current detection signal. The integrating circuit is also used to output a current reversal signal to the sampling power supply when the voltage difference across the first sampling resistor is 0. The current reversal signal is used to indicate that the current direction of the first sampling current flowing through the first sampling resistor has reversed, triggering the sampling power supply to stop increasing the output voltage and triggering the current sampling unit to acquire the second sampling current as the load current.

4. The current sampling circuit according to any one of claims 2-3, characterized in that, The integrating circuit includes a first operational amplifier, a first resistor, and a capacitor; the non-inverting input of the first operational amplifier serves as the first input of the integrating circuit, the inverting input of the first operational amplifier serves as the second input of the integrating circuit, and the output of the first operational amplifier serves as the output of the integrating circuit; the first resistor and the capacitor are connected in series between the output of the first operational amplifier and the inverting input of the first operational amplifier. The first operational amplifier is used to acquire the voltage difference across the first sampling resistor and output the current detection signal or the current reversal signal.

5. The current sampling circuit according to claim 4, characterized in that, The current sampling unit includes a first operational amplifier circuit, a second operational amplifier circuit, and a second control unit. The first input terminal of the first operational amplifier circuit is connected to the first terminal of the first sampling resistor, the second input terminal of the first operational amplifier circuit is connected to the second terminal of the first sampling resistor, the output terminal of the first operational amplifier circuit is connected to the second control unit, the first input terminal of the second operational amplifier circuit is connected to the first terminal of the second sampling resistor, the second input terminal of the second operational amplifier circuit is connected to the second terminal of the second sampling resistor, and the output terminal of the second operational amplifier circuit is connected to the second control unit. The first operational amplifier circuit is used to acquire the voltage signal across the first sampling resistor and output a first voltage sampling signal to the second control unit; The second operational amplifier circuit is used to acquire the voltage signal across the second sampling resistor and output a second voltage sampling signal to the second control unit; The second control unit is configured to obtain the magnitude of the second sampled current based on the second voltage sampling signal under the first operating condition, and output the magnitude of the second sampled current as the magnitude of the load current when the current reversal signal is received; and to obtain the magnitude of the first sampled current based on the first voltage sampling signal under the second operating condition, and to output the magnitude of the first sampled current as the magnitude of the load current when the current reversal signal is received.

6. The current sampling circuit according to claim 5, characterized in that, The second control unit is also used for; During the current sampling calibration phase when the load is empty, the sampling power supply is controlled to increase the output voltage until the current direction of the first sampling current flowing through the first sampling resistor is reversed, and the current flowing through the second sampling resistor is obtained as the calibration current when the current direction is reversed. The bias voltage of the first operational amplifier is obtained based on the calibration current and the resistance value of the first sampling resistor. The first sampling current or the second sampling current is corrected based on the bias voltage and the resistance value of the first sampling resistor to obtain the corrected load current output.

7. The current sampling circuit according to claim 5, characterized in that, The first operational amplifier circuit includes a second operational amplifier, a third operational amplifier, a fourth operational amplifier, a second resistor, a third resistor, a fourth resistor, and a fifth resistor; The non-inverting input of the second operational amplifier serves as the first input of the first operational amplifier circuit. The output of the second operational amplifier is connected to the inverting input of the second operational amplifier and connected to the inverting input of the third operational amplifier through the second resistor. The non-inverting input of the fourth operational amplifier serves as the second input of the first operational amplifier circuit. The output of the fourth operational amplifier is connected to the inverting input of the fourth operational amplifier and connected to the non-inverting input of the third operational amplifier through the third resistor. The fourth resistor is connected between the non-inverting input of the third operational amplifier and ground. The fifth resistor is connected between the output of the third operational amplifier and the inverting input of the third operational amplifier. The second operational amplifier and the fourth operational amplifier are used to acquire the voltage signal across the first sampling resistor and output a first differential signal to the third operational amplifier; The third operational amplifier is used to amplify the first differential signal to obtain the first voltage sampling signal, and output the first voltage sampling signal to the second control unit.

8. The current sampling circuit according to claim 5, characterized in that, The second operational amplifier circuit includes a fifth operational amplifier, a sixth operational amplifier, a seventh operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor; The non-inverting input of the fifth operational amplifier serves as the first input of the second operational amplifier circuit. The output of the fifth operational amplifier is connected to the inverting input of the fifth operational amplifier and is connected to the inverting input of the sixth operational amplifier through the sixth resistor. The non-inverting input of the seventh operational amplifier serves as the second input of the second operational amplifier circuit. The output of the seventh operational amplifier is connected to the inverting input of the seventh operational amplifier and is connected to the non-inverting input of the sixth operational amplifier through the seventh resistor. The eighth resistor is connected between the non-inverting input of the sixth operational amplifier and ground. The ninth resistor is connected between the output of the sixth operational amplifier and the inverting input of the sixth operational amplifier. The fifth operational amplifier and the seventh operational amplifier are used to acquire the voltage signal across the second sampling resistor and output the second differential signal to the sixth operational amplifier; The sixth operational amplifier is used to amplify the second differential signal to obtain the second voltage sampling signal, and output the second voltage sampling signal to the second control unit.

9. The current sampling circuit according to claim 2, characterized in that, The first control unit includes an analog-to-digital converter and a digital-to-analog converter; The digital-to-analog converter is used to control the sampling power supply to increase the output voltage, so as to adjust the voltage difference across the first sampling resistor; The analog-to-digital converter is used to output a voltage control signal to the digital-to-analog converter when the current reversal signal is received; The digital-to-analog converter is also used to control the sampling power supply to stop increasing the output voltage when the voltage control signal is received, so as to stop adjusting the voltage difference across the first sampling resistor.

10. A radio frequency power supply, characterized in that, The radio frequency power supply includes a power supply and a current sampling circuit as described in any one of claims 1-9.

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