Current detection circuit and charging pile

Abstract

The invention relates to the technical field of charging piles, in particular to a current detection circuit and a charging pile. The current detection circuit comprises a current sampling circuit, a segmented amplification circuit and a control circuit, the current sampling circuit is configured to be electrically connected with the output end of the DC / DC circuit and used for sampling the current of the output end of the DC / DC circuit and outputting a sampling voltage, and the segmented amplification circuit is electrically connected with the current sampling circuit and used for amplifying the sampling voltage according to a target amplification stage; outputting the amplified target voltage; the target amplification stage corresponds to the sampling voltage, and the control circuit is electrically connected with the current sampling circuit and the segmented amplification circuit and is used for detecting the output end current of the DC / DC circuit according to the target detection mode and the target voltage; the target detection mode corresponds to the sampling voltage. According to the embodiment of the invention, the current can be sampled in a segmented manner, different gains are adopted for amplification for different current sections, and the sampling precision of the target current section can be improved on the basis of avoiding the sampling cut-off problem.

Description

Technical Field

[0001] The present invention relates to the technical field of charging piles, and in particular to a current detection circuit and a charging pile. Background Art

[0002] The rise of new energy vehicles and people's pursuit of convenience in life have driven the emergence of high-power super charging piles. In practical applications, it is generally necessary to detect the output current of a high-power super charging pile to achieve feedback control of battery charging and ensure the battery charging effect. Since a high-power super charging pile needs to output high power, the range of the output current is relatively wide. If a high-resolution analog-to-digital converter is used to sample the output current, it is easy to cause the current sampling signal to exceed the range of the analog-to-digital converter, resulting in sampling cutoff, thereby reducing the authenticity and reliability of the sampling. If a low-resolution analog-to-digital converter is used to sample the output current, the sampling accuracy of the target current segment cannot be ensured, thereby affecting the precise feedback control of battery charging. Summary of the invention

[0003] An object of the present invention is to provide a current detection circuit and a charging pile to solve the technical problems of sampling cutoff or low sampling accuracy in output current sampling in the related art.

[0004] In a first aspect, an embodiment of the present invention provides a current detection circuit, comprising:

[0005] A current sampling circuit is configured to be electrically connected to the output end of the DC / DC circuit, and is used to sample the output end current of the DC / DC circuit and output a sampled voltage;

[0006] A segmented amplifier circuit, electrically connected to the current sampling circuit, for amplifying the sampled voltage according to a target amplification stage and outputting the amplified target voltage; the target amplification stage corresponds to the sampled voltage;

[0007] The control circuit is electrically connected to the current sampling circuit and the segmented amplifier circuit respectively, and is used to detect the output current of the DC / DC circuit according to a target detection mode and a target voltage; the target detection mode corresponds to the sampling voltage.

[0008] Optionally, the target amplification stage includes a first amplification stage and a second amplification stage;

[0009] When the sampling voltage is less than or equal to the reference voltage, the segmented amplifier circuit operates in the first amplification stage; when the sampling voltage is greater than the reference voltage, the segmented amplifier circuit operates in the second amplification stage, wherein the gain of the first amplification stage is greater than the gain of the second amplification stage.

[0010] Optionally, the segmented amplifier circuit includes:

[0011] A first amplifier circuit, electrically connected to the current sampling circuit, configured to amplify the sampled voltage and output an amplified first voltage;

[0012] The logic circuit is electrically connected to the current sampling circuit and the first amplifying circuit respectively, and is configured to input the reference voltage. When the sampling voltage is less than or equal to the reference voltage, the logic circuit outputs a target voltage according to the sampling voltage and the first voltage in the first amplifying stage; when the sampling voltage is greater than the reference voltage, the logic circuit outputs a target voltage according to the sampling voltage and the first voltage in the second amplifying stage.

[0013] Optionally, the logic circuit includes:

[0014] a second amplifier circuit, electrically connected to the current sampling circuit and configured to input the reference voltage, to output a first preset voltage when the sampling voltage is less than or equal to the reference voltage, and to amplify the sampling voltage and output a second voltage when the sampling voltage is greater than the reference voltage;

[0015] The subtractor is electrically connected to the first amplifier circuit and the second amplifier circuit respectively, and is used to output a target voltage according to the first voltage and the first preset voltage in the first amplifier stage, and to output a target voltage according to the first voltage and the second voltage in the second amplifier stage.

[0016] Optionally, the first preset voltage is zero, and the gain of the first amplifier circuit is greater than the gain of the second amplifier circuit.

[0017] Optionally, the logic circuit includes:

[0018] a third amplifier circuit, electrically connected to the current sampling circuit and configured to input the reference voltage, and to amplify the sampled voltage and output a third voltage when the sampled voltage is less than or equal to the reference voltage, and to output a second preset voltage when the sampled voltage is greater than the reference voltage;

[0019] The adder is electrically connected to the first amplifier circuit and the third amplifier circuit respectively, and is used to output a target voltage according to the first voltage and the third voltage in the first amplifier stage, and to output a target voltage according to the first voltage and the second preset voltage in the second amplifier stage.

[0020] Optionally, the target detection mode includes a first detection mode and a second detection mode;

[0021] When the sampling voltage is less than or equal to the reference voltage, the control circuit detects the output current of the DC / DC circuit according to the target voltage in the first detection mode; when the sampling voltage is greater than the reference voltage, the control circuit detects the output current of the DC / DC circuit according to the target voltage in the second detection mode.

[0022] Optionally, the control circuit includes:

[0023] a comparator, electrically connected to the current sampling circuit and configured to input a reference voltage, and to output a first level signal when the sampling voltage is less than or equal to the reference voltage, and to output a second level signal when the sampling voltage is greater than the reference voltage;

[0024] The controller is electrically connected to the comparator and the segmented amplifier circuit respectively, and is used to work in a first detection mode according to the first level signal, and work in a second detection mode according to the second level signal.

[0025] Optionally, the current sampling circuit includes:

[0026] A sampling resistor is configured to be electrically connected to an output terminal of a DC / DC circuit, and a current at the output terminal of the DC / DC circuit flows through the sampling resistor;

[0027] The fourth amplifier circuit is electrically connected to the sampling resistor and is used to collect the voltage difference between the two ends of the sampling resistor and output a sampling voltage according to the voltage difference.

[0028] In a second aspect, an embodiment of the present invention provides a charging pile, comprising the current detection circuit as described above.

[0029] Compared with the related art, the embodiment of the present invention provides a current detection circuit and a charging pile, the current detection circuit includes a current sampling circuit, a segmented amplifier circuit and a control circuit, the current sampling circuit is configured to be electrically connected to the output end of the DC / DC circuit, for sampling the output end current of the DC / DC circuit and outputting a sampling voltage, the segmented amplifier circuit is electrically connected to the current sampling circuit, for amplifying the sampling voltage according to the target amplification stage, and outputting the amplified target voltage, the target amplification stage corresponds to the sampling voltage, the control circuit is electrically connected to the current sampling circuit and the segmented amplifier circuit respectively, for detecting the output end current of the DC / DC circuit according to the target detection mode and the target voltage; the target detection mode corresponds to the sampling voltage. Therefore, the present embodiment can sample the current in segments, and adopt different gains for amplification for different current intervals. On the one hand, since a higher gain is adopted for the target current interval, the sampling accuracy of the target current interval can be improved. On the other hand, since a relatively low gain is adopted for the current intervals other than the target current interval, the target voltage can be controlled within a reasonable voltage range, thereby avoiding the problem of sampling cutoff, and ensuring the authenticity and reliability of the detection result. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0031] Figure 1 A schematic diagram of an application scenario of a charging pile provided by an embodiment of the present invention;

[0032] Figure 2 A schematic diagram of the structure of a charging pile provided by an embodiment of the present invention;

[0033] Figure 3 A schematic diagram of the structure of a current detection circuit provided by an embodiment of the present invention;

[0034] Figure 4 A schematic diagram of the structure of a current detection circuit provided by another embodiment of the present invention;

[0035] Figure 5 A schematic diagram of a segmented amplification curve provided by an embodiment of the present invention;

[0036] Figure 6 A schematic diagram of the structure of a current detection circuit provided by another embodiment of the present invention;

[0037] Figure 7A schematic structural diagram of a current detection circuit provided by yet another embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] It should be noted that, if there is no conflict, the various features in the embodiments of the present invention can be combined with each other, all within the scope of protection of the present invention. In addition, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in a different order from the module division in the device or the flow chart. Furthermore, the words "first", "second", "third", etc. used in the present invention do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0040] See also Figure 1 , Figure 1 A schematic diagram of an application scenario of a charging pile is provided for an embodiment of the present invention, such as Figure 1 As shown, the application scenario includes a charging pile 100 , a power grid 200 and an electric vehicle 300 .

[0041] The power grid 200 is a power network that transmits city power to the charging pile 100 through a transmission line to supply power to the electric vehicle 300. The city power is industrial frequency alternating current, which is usually characterized by voltage, current and frequency. Generally, the city power transmitted from the power grid 200 to the charging pile 100 is three-phase alternating current.

[0042] The charging pile 100 is a device for charging the electric vehicle 300 to replenish the electric power of the electric vehicle 300. Its working principle is to receive electric energy from the power grid 200, and then transmit the electric energy to the electric vehicle 300 through the charging line to charge the electric vehicle 300. The charging pile 100 can be any type of charging pile that can support AC charging, such as a DC charging pile, an AC charging pile, an AC / DC integrated charging pile, etc.

[0043] The DC charging pile uses direct current to charge the power battery of the electric vehicle 300. This charging method is also called "fast charging". The DC charging pile is electrically connected to the power grid 200, and can receive three-phase 380V alternating current input from the power grid 200 and convert the alternating current into direct current, which is then transmitted to the power battery of the electric vehicle 300 for charging through a standard DC charging plug and charging socket, thereby achieving DC charging. The power supply characteristics of the DC charging pile itself determine that it can output sufficient charging power, and the adjustment range of voltage and current is relatively large, thereby achieving fast charging. The DC charging pile has a charger function, which can monitor and control the working status of the charged power battery in real time, and can also measure the charging power.

[0044] The AC charging pile generally uses a single or dual 220VAC / 380VAC AC output interface to provide power to the electric vehicle 300 so that the electric vehicle 300 can use the on-board charger to charge its power battery. This charging method is also called "slow charging". The output power of the AC charging pile is usually 5kW (220VAC) / 20kW (380VAC), but the actual charging power is restricted by the on-board charger. Generally, the on-board charging power of a small electric vehicle is between 2 and 3kW. The on-board charger of the electric vehicle 300 can convert the AC power into DC power by filtering and rectifying, and then store the DC power in the power battery of the electric vehicle 300, thereby charging the electric vehicle 300. This charging method is mainly used in small pure electric vehicles.

[0045] The input voltage of the AC / DC integrated charging pile is generally three-phase four-wire 380VAC±15%, with a frequency of 50Hz. The AC / DC integrated charging pile includes a DC output port and an AC output port, wherein the DC output port outputs adjustable DC power to charge the power battery of the electric vehicle 300, and the charging power is generally 10-40kW, and the AC output port outputs 220VAC (5kW) / 380VAC (20kW) AC power to provide charging power for the on-board charger of the electric vehicle 300. The AC / DC integrated charging pile can provide conventional charging through the AC output port and fast charging through the DC output port. When there are many charging services during the day, fast charging is used for fast charging. When there are few users at the charging station at night, conventional charging can be used for slow charging. The AC / DC integrated charging pile can realize both AC and DC charging at the same time, and interlocking charging. It adopts modular design for easy maintenance.

[0046] In some embodiments, the charging pile 100 is configured with one or more charging guns, which are interface devices connecting the charging pile and the electric vehicle 300, and are mainly used to transfer electric energy to charge the electric vehicle 300. The charging gun usually has a plug and a connecting wire, one end of which is connected to the charging pile and the other end is inserted into the charging interface of the electric vehicle 300. According to different charging requirements and technical standards, the charging gun can be divided into a fast charging gun and a slow charging gun.

[0047] Fast charging guns are also called DC fast charging guns. They are usually used in fast charging stations. They have a large power output and can quickly charge the vehicle's power battery.

[0048] Slow charging guns are also called AC charging guns. They are usually used in home charging piles, commercial charging piles and public charging piles. They have low power and are suitable for charging with ordinary household power supply. The charging speed is relatively slow.

[0049] The electric vehicle 300 can receive AC or DC power provided by the charging pile 100. When the electric vehicle 300 receives DC power, the electric vehicle 300 can store the DC power in the power battery of the electric vehicle 300, thereby charging the power battery of the electric vehicle 300. When the electric vehicle 300 receives AC power, the electric vehicle 300 can convert the voltage, filter, and rectify the AC power to obtain DC power, and then store the DC power in the power battery of the electric vehicle 300, thereby charging the power battery of the electric vehicle 300. The electric vehicle 300 includes any vehicle that can be driven by electricity, including but not limited to pure electric vehicles, hybrid electric vehicles, fuel cell vehicles, etc.

[0050] In some embodiments, see Figure 2 The charging pile 100 includes an input filter circuit 10, an AC / DC circuit 20, a DC / DC circuit 30, an output filter circuit 40, an auxiliary power supply 50, a charging control module 60, a current detection circuit 70, a metering module 80 and a communication module 90.

[0051] The input filter circuit 10 is configured to be electrically connected to the power grid 200 . The input filter circuit 10 is used to filter out high-frequency interference signals, thereby reducing conducted interference.

[0052] The AC / DC circuit 20 is electrically connected to the input filter circuit 10, and is used to convert the AC power of the power grid 200 into DC power. The AC / DC circuit 20 may include any circuit for converting AC power into DC power, including but not limited to a three-phase active PFC (Power Factor Correction) circuit, a three-phase neutral-free Vienna circuit, etc.

[0053] The DC / DC circuit 30 is electrically connected to the AC / DC circuit 20, and is used to convert the direct current output by the AC / DC circuit 20 into a voltage waveform that meets the battery charging strategy. The DC / DC circuit 30 can be any circuit used to convert the direct current output by the AC / DC circuit 20 into a voltage waveform that meets the battery charging strategy, including but not limited to LLC resonant circuit, three-phase interleaved LLC resonant circuit, DAB (dual active bridge converter), bidirectional full-bridge CLLC resonant circuit, three-phase interleaved CLLC resonant circuit, phase-shifted full-bridge circuit, etc.

[0054] The output filter circuit 40 is electrically connected to the DC / DC circuit 30 and the electric vehicle 300 respectively. The output filter circuit 40 is used to filter out the electromagnetic interference generated by the charging pile 100 during operation, ensure stable communication between the charging pile 100 and the electric vehicle 300, and avoid charging errors or safety problems caused by interference.

[0055] The auxiliary power supply 50 is electrically connected to the AC / DC circuit 20 and is used to convert the direct current output by the AC / DC circuit 20 into a power supply, which is used to supply power to the charging control module 60 .

[0056] The charging control module 60 is electrically connected to the AC / DC circuit 20 , the DC / DC circuit 30 and the auxiliary power supply 50 , respectively, and is used to work under the power supply of the auxiliary power supply 50 and control the voltage conversion of the AC / DC circuit 20 and the DC / DC circuit 30 .

[0057] The current detection circuit 70 is electrically connected to the output end of the DC / DC circuit 30 and is used to detect the output end current of the DC / DC circuit 30 so as to subsequently adjust and control the charging current according to the output end current.

[0058] The metering module 80 is electrically connected to the charging control module 60. The metering module 80 includes metering function, monitoring function and management function. The metering function is responsible for accurately measuring parameters such as power, voltage, current, etc. during the charging process, and feeding back the data to the charging control module 60 to ensure accurate measurement of the charging power. The monitoring function is responsible for real-time monitoring of the operation of the charging pile 100, including power, time, cost, etc., to ensure the normal operation of the charging pile 100. The management function is responsible for managing the charging pile 100, such as setting charging prices, counting charging volume and costs, etc., to provide data support and business basis for operators.

[0059] The communication module 90 is electrically connected to the charging control module 60 and the electric vehicle 300 respectively, and is used to establish communication between the charging control module 60 and the electric vehicle 300. Based on the established communication, the charging pile 100 can interact with the electric vehicle 300. When the charging pile 100 interacts with the electric vehicle 300, various charging interaction information can be sent and received between the charging pile 100 and the electric vehicle 300. The interaction between the electric vehicle 300 and the charging pile 100 during the charging process can be roughly divided into a charging parameter configuration stage and a charging stage. The charging pile 100 is physically connected to the electric vehicle 300 and powered on, and enters the charging parameter configuration stage after checking that the voltage is normal. In the charging stage, the charging pile 100 adjusts the charging voltage and charging current according to the charging requirements of the battery management system of the electric vehicle 300 to ensure that the charging process proceeds normally.

[0060] In some embodiments, see Figure 3 The current detection circuit 70 includes a current sampling circuit 71 , a segmented amplifier circuit 72 and a control circuit 73 .

[0061] The current sampling circuit 71 is configured to be electrically connected to the output end of the DC / DC circuit 30 , and is used to sample the output end current of the DC / DC circuit 30 and output a sampled voltage.

[0062] In this embodiment, the current sampling circuit 71 can use any suitable current sampling method to sample the output current of the DC / DC circuit 30, including but not limited to the resistance sampling method, the mutual inductance sampling method, the Hall element sampling method, etc., wherein the resistance sampling method converts the current into a voltage signal through a series resistor, and then uses a sensor to measure the voltage value, thereby obtaining the magnitude of the current in the circuit. The principle of the mutual inductance sampling method is to use a mutual inductor to convert the current into a voltage signal, and then use a sensor to measure the voltage value, thereby obtaining the magnitude of the current in the circuit. The principle of the Hall element sampling method is to apply the current to the Hall element, measure the Hall voltage on both sides of the element, and thereby obtain the current value.

[0063] In some embodiments, see Figure 4 The current sampling circuit 71 includes a sampling resistor 711 and a fourth amplifier circuit 712 .

[0064] The sampling resistor 711 is configured to be electrically connected to the output end of the DC / DC circuit 30 . The output end current of the DC / DC circuit 30 flows through the sampling resistor 711 . It can be understood that since the output end current flows through the sampling resistor 711 , a voltage difference is formed across the sampling resistor 711 .

[0065] The sampling resistor 711 may be any suitable type of resistor, including but not limited to a carbon film resistor, a metal film resistor, a wire wound resistor, a cement resistor, a chip resistor, etc. In practical applications, the sampling resistor can truly reflect the current and voltage conditions, and thus its accuracy is often required to be relatively high. Therefore, in some embodiments, in order to improve the current sampling accuracy, the sampling resistor 711 uses a precision current sampling resistor.

[0066] The fourth amplifier circuit 712 is electrically connected to the sampling resistor 711, and is used to collect the voltage difference across the sampling resistor 711 and output a sampling voltage according to the voltage difference. The fourth amplifier circuit 712 linearly amplifies the voltage difference and outputs the sampling voltage. Therefore, there is a linear relationship between the sampling voltage and the output current of the DC / DC circuit 30.

[0067] Generally speaking, when the sampling resistor 711 is used for precise current sampling, the resistance of the sampling resistor 711 is required to be very small, otherwise a large error is likely to occur. According to Ohm's law, when the current flowing through the sampling resistor 711 remains unchanged, if the resistance of the sampling resistor 711 is small, the voltage difference across the sampling resistor 711 is also small. Therefore, in order to facilitate subsequent processing, the voltage difference needs to be amplified.

[0068] The fourth amplifier circuit 712 may be any suitable type of amplifier circuit, including but not limited to an operational amplifier, a differential amplifier, an instrumentation amplifier, a transistor amplifier, etc. In some embodiments, the fourth amplifier circuit 712 is an operational amplifier. In practical applications, operational amplifiers are susceptible to noise, offset voltage and current, temperature drift, and other factors, which may cause amplification errors, thereby affecting amplification accuracy. Therefore, in some embodiments, in order to more accurately amplify the voltage signal, the operational amplifier uses a precision operational amplifier. The precision operational amplifier has a very high open-loop gain, very small offset voltage or offset current, low noise level, and small temperature drift, so it can be used in applications with high precision requirements.

[0069] The segmented amplifier circuit 72 is electrically connected to the current sampling circuit 71 and is used to amplify the sampling voltage according to a target amplification stage and output the amplified target voltage. The target amplification stage corresponds to the sampling voltage.

[0070] Different sampling voltages may correspond to different amplification stages. For example, the sampling voltage can be divided into different voltage intervals within a preset voltage range, and the different voltage intervals correspond to different current intervals and different amplification stages of the output current of the DC / DC circuit 30, respectively. The division of current intervals or voltage intervals can be set according to actual needs. For example, the output current of the DC / DC circuit 30 is divided into three current intervals: (I0, I1), (I1, I2) and (I2, I3), and correspondingly, the sampling voltage is divided into three voltage intervals: (V0, V1), (V1, V2) and (V2, V3), wherein the current interval (I0, I1) corresponds to the voltage interval (V0, V1) and amplification stage 1, the current interval (I1, I2) corresponds to the voltage interval (V1, V2) and amplification stage 2, and the current interval (I2, I3) corresponds to the voltage interval (V2, V3) and amplification stage 3, wherein amplification stage 1, amplification stage 2 and amplification stage 3 are different amplification stages from each other.

[0071] The gains (amplification factors) of different amplification stages are different. As mentioned above, amplification stage 1 corresponds to gain Av1, amplification stage 2 corresponds to gain Av2, and amplification stage 3 corresponds to gain Av3.

[0072] As mentioned above, if the output current of the DC / DC circuit 30 is in the current interval (I0, I1), the sampling voltage output by the current sampling circuit 71 is in the voltage interval (V0, V1). At this time, the segmented amplifier circuit 72 operates in the amplification stage 1 according to the sampling voltage, and amplifies the sampling voltage by Av1 times to output the target voltage. Assuming that the sampling voltage is Vs1, the target voltage Vt1 = Vs1*Av1. The same is true when the output current of the DC / DC circuit 30 is in other current intervals, which will not be repeated here.

[0073] The control circuit 73 is electrically connected to the current sampling circuit 71 and the segmented amplifier circuit 72 respectively, and is used to detect the output current of the DC / DC circuit 30 according to the target detection mode and the target voltage. The target detection mode corresponds to the sampling voltage.

[0074] Different sampling voltages may correspond to different detection modes. For example, the sampling voltage includes three voltage intervals: (V0, V1), (V1, V2) and (V2, V3). The voltage interval (V0, V1) corresponds to the first detection mode, the voltage interval (V1, V2) corresponds to the second detection mode, and the voltage interval (V2, V3) corresponds to the third detection mode. The first detection mode, the second detection mode and the third detection mode are different detection modes from each other.

[0075] The control circuit 73 can determine the target detection mode according to the sampled voltage. As described above, when the sampled voltage is in the voltage interval (V1, V2), the control circuit 73 can determine the second detection mode. After determining the target detection mode, the control circuit 73 can convert the target voltage in the target detection mode to obtain a conversion result, which can be used to represent the current value of the output terminal current of the DC / DC circuit 30, thereby realizing the output terminal current detection of the DC / DC circuit 30.

[0076] The control circuit 73 can use ADCs (Analog to Digital Converters) with different quantization resolutions in different detection modes. As mentioned above, the control circuit 73 can use a 16-bit ADC in the first detection mode and a 12-bit ADC in the second detection mode. The control circuit 73 can also use an ADC with the same resolution but different detection configurations in different detection modes, such as the mapping relationship between the conversion result and the output current of the DC / DC circuit 30.

[0077] Therefore, this embodiment can sample the current in segments and use different gains for amplification in different current intervals. On the one hand, since a higher gain is used for the target current interval, the sampling accuracy of the target current interval can be improved. On the other hand, since a relatively low gain is used for current intervals other than the target current interval, the target voltage can be controlled within a reasonable voltage range, thereby avoiding the problem of sampling cutoff and ensuring the authenticity and reliability of the detection results.

[0078] In some embodiments, the target amplification stage includes a first amplification stage and a second amplification stage. When the sampling voltage is less than or equal to the reference voltage, the segmented amplification circuit 72 operates in the first amplification stage; when the sampling voltage is greater than the reference voltage, the segmented amplification circuit 72 operates in the second amplification stage, wherein the gain of the first amplification stage is greater than the gain of the second amplification stage.

[0079] Since the gain of the first amplification stage is greater than the gain of the second amplification stage, and the first amplification stage corresponds to a voltage interval that is less than or equal to the reference voltage, and also corresponds to a small current interval, and the first amplification stage corresponds to a voltage interval that is greater than the reference voltage, and also corresponds to a large current interval, therefore, the present embodiment can use a higher gain for the small current interval, thereby improving the sampling accuracy of the small current interval, that is, when the output current of the DC / DC circuit 30 is in the small current interval, the detection accuracy of the output current of the DC / DC circuit 30 can be improved, and the present embodiment can use a lower gain for the large current interval, thereby avoiding excessive target voltage and thus avoiding sampling cutoff.

[0080] See also Figure 5 , Figure 5 A schematic diagram of a segmented amplification curve provided by an embodiment of the present invention, such as Figure 5 As shown in FIG. 1 , Vs represents the sampling voltage, Vt represents the target voltage, VREF represents the reference voltage, and the slope is the ratio (gain) of the target voltage to the sampling voltage. Figure 5 It can be seen that the first amplification stage and the second amplification stage are continuous, and at the junction of the first amplification stage and the second amplification stage, that is, when the sampling voltage is equal to the reference voltage, the segmented amplifier circuit 72 can still output the target voltage. Therefore, even if there is a sudden change in the gain between the first amplification stage and the second amplification stage, it can ensure that the first amplification stage and the second amplification stage have a smooth and soft transition, thereby preventing drastic changes in the detection results at the junction of different amplification stages, thereby improving the consistency and integrity of the detection results.

[0081] In some embodiments, the reference voltage can be obtained by dividing a preset voltage through resistors, or by using a reference source.

[0082] In some embodiments, the target detection mode includes a first detection mode and a second detection mode. When the segmented amplifier circuit 72 operates in the first amplification stage, the control circuit 73 detects the output current of the DC / DC circuit 30 according to the target voltage in the first detection mode; when the segmented amplifier circuit 72 operates in the second amplification stage, the control circuit 73 detects the output current of the DC / DC circuit 30 according to the target voltage in the second detection mode.

[0083] As described above, the control circuit 73 can determine whether the segmented amplifier circuit 72 is currently operating in the first amplification stage or the second amplification stage based on the sampled voltage, so that in the target detection mode matching the target amplification stage, the output current of the DC / DC circuit 30 can be detected according to the target voltage, thereby improving the flexibility and accuracy of the output current detection of the DC / DC circuit 30.

[0084] In some embodiments, please refer to Figure 4 The segmented amplifier circuit 72 includes a first amplifier circuit 721 and a logic circuit 722 .

[0085] The first amplifier circuit 721 is electrically connected to the current sampling circuit 71 and is used to amplify the sampled voltage and output the amplified first voltage.

[0086] The first amplifier circuit 721 may be any suitable voltage amplifier circuit, including but not limited to an operational amplifier circuit, a differential amplifier circuit, an inverting amplifier circuit, etc.

[0087] In some embodiments, there is a linear proportional relationship between the first voltage and the sampled voltage.

[0088] The logic circuit 722 is electrically connected to the current sampling circuit 71 and the first amplifier circuit 721 respectively and is configured to input a reference voltage. When the sampling voltage is less than or equal to the reference voltage, the logic circuit 722 outputs a target voltage according to the sampling voltage and the first voltage in the first amplification stage. When the sampling voltage is greater than the reference voltage, the logic circuit 722 outputs a target voltage according to the sampling voltage and the first voltage in the second amplification stage.

[0089] The logic circuit 722 may include logic gates, triggers, combinational logic circuits, sequential logic circuits or combinations thereof, wherein logic gates include but are not limited to AND gates, OR gates, NOT gates, NAND gates, NOR gates, XOR gates, etc., triggers include but are not limited to RS triggers, D triggers, JK triggers, etc., combinational logic circuits include but are not limited to encoders, decoders, data selectors, etc., sequential logic circuits include but are not limited to counters, registers, etc.

[0090] In some embodiments, see Figure 6 , the logic circuit 722 includes a second amplifier circuit 7221 and a subtractor 7222.

[0091] The second amplifier circuit 7221 is electrically connected to the current sampling circuit 71 and is configured to input a reference voltage, and is used to output a first preset voltage when the sampling voltage is less than or equal to the reference voltage, and to amplify the sampling voltage and output a second voltage when the sampling voltage is greater than the reference voltage.

[0092] The second amplifier circuit 7221 can be any suitable voltage amplifier circuit, including but not limited to an operational amplifier circuit, a differential amplifier circuit, an inverting amplifier circuit, etc.

[0093] The first preset voltage can be set according to actual needs, and its specific voltage value is not limited here. In some embodiments, the first preset voltage is zero.

[0094] In some embodiments, the second voltage is linearly proportional to the sampling voltage.

[0095] The subtractor 7222 is electrically connected to the first amplifier circuit 721 and the second amplifier circuit 7221 respectively, and is used to output a target voltage according to the first voltage and the first preset voltage in the first amplification stage, and to output a target voltage according to the first voltage and the second voltage in the second amplification stage.

[0096] In some embodiments, in the first amplification stage, the subtractor 7222 subtracts the first preset voltage from the first voltage to obtain a target voltage, and in the second amplification stage, the subtractor 7222 subtracts the second voltage from the first voltage to obtain a target voltage.

[0097] It can be understood that, in the first amplification stage, if the first preset voltage is zero, the target voltage is equal to the first voltage.

[0098] In some embodiments, the gain of the first amplifier circuit 721 is greater than the gain of the second amplifier circuit 7221 .

[0099] Since in the second amplification stage, the target voltage is obtained by subtracting the second voltage from the first voltage by the subtractor 7222, and the first voltage and the second voltage are both obtained by linearly amplifying the sampled voltage, by setting the gain of the first amplifier circuit 721 to be greater than the gain of the second amplifier circuit 7221, it can be ensured that in the second amplification stage, the target voltage is greater than zero and less than the first voltage.

[0100] Therefore, in the first amplification stage, the sampling voltage is amplified with the highest gain by the first amplification circuit 721, and in the second amplification stage, the sampling voltage is amplified with a lower gain by offsetting a part of the gain of the first amplification circuit 721 by the gain of the second amplification circuit 7221, so that the gain of the first amplification stage is greater than the gain of the second amplification stage.

[0101] In some embodiments, see Figure 7 , the logic circuit 722 includes a third amplifier circuit 7223 and an adder 7224.

[0102] The third amplifier circuit 7223 is electrically connected to the current sampling circuit 71 and is configured to input a reference voltage, and is used to amplify the sampling voltage and output a third voltage when the sampling voltage is less than or equal to the reference voltage, and to output a second preset voltage when the sampling voltage is greater than the reference voltage.

[0103] The second preset voltage can be set according to actual needs, and its specific voltage value is not limited here. In some embodiments, the first preset voltage is zero.

[0104] In some embodiments, the third voltage is linearly proportional to the sampling voltage.

[0105] The adder 7224 is electrically connected to the first amplifier circuit 721 and the third amplifier circuit 7223 respectively, and is used to output the target voltage according to the first voltage and the third voltage in the first amplification stage, and to output the target voltage according to the first voltage and the second preset voltage in the second amplification stage.

[0106] In some embodiments, in the first amplification stage, the adder 7224 adds the third voltage to the first voltage to obtain a target voltage, and in the second amplification stage, the adder 7224 adds the second preset voltage to the first voltage to obtain a target voltage.

[0107] In the second amplification stage, if the second preset voltage is zero, the target voltage is equal to the first voltage.

[0108] It is understandable that, since in the first amplification stage, the target voltage is obtained by adding the first voltage to the second voltage by the adder 7224, it is only necessary to set the gain of the third amplifier circuit 7223 to be greater than 1 to ensure that the target voltage is greater than the first voltage.

[0109] Therefore, in the first amplification stage, the sampling voltage is amplified with the highest gain by superimposing the gain of the first amplification circuit 721 and the gain of the third amplification circuit 7223. In the second amplification stage, the sampling voltage is amplified with a lower gain by superimposing the gain of the first amplification circuit 721, so that the gain of the first amplification stage is greater than the gain of the second amplification stage.

[0110] In some embodiments, please refer to Figure 4 , the control circuit 73 includes a comparator 731 and a controller 732 .

[0111] The comparator 731 is electrically connected to the current sampling circuit 71 and is configured to input a reference voltage, and to output a first level signal when the sampling voltage is less than or equal to the reference voltage, and to output a second level signal when the sampling voltage is greater than the reference voltage.

[0112] The first level signal and the second level signal are signals of different levels. For example, the first level signal is a high level signal and the second level signal is a low level signal, or the first level signal is a low level signal and the second level signal is a high level signal.

[0113] The controller 732 is electrically connected to the comparator 731 and the segmented amplifier circuit 72 respectively, and is used to operate in the first detection mode according to the first level signal, and operate in the second detection mode according to the second level signal.

[0114] Therefore, the controller 732 can conveniently determine the voltage interval in which the sampling voltage is currently located according to the level signal output by the comparator 731, so as to operate in the target detection mode corresponding to the sampling voltage, thereby synchronizing with the target amplification stage in which the segmented amplifier circuit 72 is currently located.

[0115] In some embodiments, please refer to Figure 6 or Figure 7 The non-inverting input terminal of the comparator 731 is electrically connected to the current sampling circuit 71 , the inverting input terminal of the comparator 731 is configured to input a reference voltage, and the output terminal of the comparator 731 is electrically connected to the controller 732 .

[0116] In some embodiments, the comparator 731 is a high-speed comparator, which has higher performance than ordinary comparators, such as faster response time, higher sensitivity, higher output driving capability, etc.

[0117] In some embodiments, the controller 732 may include any general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), single chip microcomputer, ARM (Acorn RICS Machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components or any combination of these components. In addition, the controller 732 may also include any conventional processor, controller, microcontroller or state machine. The controller 732 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP and / or any other such configuration.

[0118] Finally, it should be noted that the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not intended to be additional limitations on the content of the present invention. The purpose of providing these implementations is to make the understanding of the disclosure of the present invention more thorough and comprehensive. And under the idea of ​​the present invention, the above-mentioned technical features continue to be combined with each other, and there are many other changes in different aspects of the present invention as described above, which are all considered to be within the scope of the present invention. Further, for those of ordinary skill in the art, improvements or changes can be made according to the above description, and all these improvements and changes should belong to the scope of protection of the claims attached to the present invention.

Claims

1. A current detection circuit, characterized in that: include: A current sampling circuit is configured to be electrically connected to the output end of the DC / DC circuit, and is used to sample the output end current of the DC / DC circuit and output a sampled voltage; A segmented amplifier circuit, electrically connected to the current sampling circuit, for amplifying the sampled voltage according to a target amplification stage and outputting an amplified target voltage; The target amplification stage corresponds to the sampling voltage; The control circuit is electrically connected to the current sampling circuit and the segmented amplifier circuit respectively, and is used to detect the output current of the DC / DC circuit according to a target detection mode and a target voltage; the target detection mode corresponds to the sampling voltage.

2. The current detection circuit according to claim 1, characterized in that: The target amplification stage includes a first amplification stage and a second amplification stage; When the sampling voltage is less than or equal to the reference voltage, the segmented amplifier circuit operates in the first amplification stage; when the sampling voltage is greater than the reference voltage, the segmented amplifier circuit operates in the second amplification stage, wherein the gain of the first amplification stage is greater than the gain of the second amplification stage.

3. The current detection circuit according to claim 2, characterized in that: The segmented amplifier circuit comprises: A first amplifier circuit, electrically connected to the current sampling circuit, configured to amplify the sampled voltage and output an amplified first voltage; The logic circuit is electrically connected to the current sampling circuit and the first amplifying circuit respectively, and is configured to input the reference voltage. When the sampling voltage is less than or equal to the reference voltage, the logic circuit outputs a target voltage according to the sampling voltage and the first voltage in the first amplifying stage; when the sampling voltage is greater than the reference voltage, the logic circuit outputs a target voltage according to the sampling voltage and the first voltage in the second amplifying stage.

4. The current detection circuit according to claim 3, characterized in that: The logic circuit comprises: a second amplifier circuit, electrically connected to the current sampling circuit and configured to input the reference voltage, to output a first preset voltage when the sampling voltage is less than or equal to the reference voltage, and to amplify the sampling voltage and output a second voltage when the sampling voltage is greater than the reference voltage; The subtractor is electrically connected to the first amplifier circuit and the second amplifier circuit respectively, and is used to output a target voltage according to the first voltage and the first preset voltage in the first amplifier stage, and to output a target voltage according to the first voltage and the second voltage in the second amplifier stage.

5. The current detection circuit according to claim 4, characterized in that: The first preset voltage is zero, and the gain of the first amplifier circuit is greater than the gain of the second amplifier circuit.

6. The current detection circuit according to claim 3, characterized in that: The logic circuit comprises: a third amplifier circuit, electrically connected to the current sampling circuit and configured to input the reference voltage, and to amplify the sampled voltage and output a third voltage when the sampled voltage is less than or equal to the reference voltage, and to output a second preset voltage when the sampled voltage is greater than the reference voltage; The adder is electrically connected to the first amplifier circuit and the third amplifier circuit respectively, and is used to output a target voltage according to the first voltage and the third voltage in the first amplifier stage, and to output a target voltage according to the first voltage and the second preset voltage in the second amplifier stage.

7. The current detection circuit according to claim 1, characterized in that: The target detection mode includes a first detection mode and a second detection mode; When the sampling voltage is less than or equal to the reference voltage, the control circuit detects the output current of the DC / DC circuit according to the target voltage in the first detection mode; when the sampling voltage is greater than the reference voltage, the control circuit detects the output current of the DC / DC circuit according to the target voltage in the second detection mode.

8. The current detection circuit according to claim 7, characterized in that: The control circuit comprises: a comparator, electrically connected to the current sampling circuit and configured to input a reference voltage, and to output a first level signal when the sampling voltage is less than or equal to the reference voltage, and to output a second level signal when the sampling voltage is greater than the reference voltage; The controller is electrically connected to the comparator and the segmented amplifier circuit respectively, and is used to work in a first detection mode according to the first level signal, and work in a second detection mode according to the second level signal.

9. The current detection circuit according to any one of claims 1 to 8, characterized in that: The current sampling circuit comprises: A sampling resistor is configured to be electrically connected to an output terminal of a DC / DC circuit, and a current at the output terminal of the DC / DC circuit flows through the sampling resistor; The fourth amplifier circuit is electrically connected to the sampling resistor and is used to collect the voltage difference between the two ends of the sampling resistor and output a sampling voltage according to the voltage difference.

10. A charging pile, characterized in that: The method comprises a current detection circuit as claimed in any one of claims 1 to 9.

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