A bidirectional current smoothing switching system, method, and dual-quadrant power supply with no crossover distortion

Abstract

This invention relates to a bidirectional current smooth switching system, method, and dual-quadrant power supply with no crossover distortion. The system includes a signal setting unit, a dynamically biased ClassAB push-pull output unit, a feedback sampling unit, and a control processing unit. The dynamically biased ClassAB push-pull output unit provides static micro-conduction bias to the N-type and P-type power transistors in the push-pull output subunit through its internal bias subunit. Combined with closed-loop control, this ensures a continuous and smooth transition when the system output current switches between positive and negative zero points, completely eliminating the crossover distortion and switching dead zone problems present in traditional bidirectional power supplies. This invention achieves high-efficiency, high-speed, and distortion-free bidirectional current output, simplifies the system structure, and can be widely applied in high-precision test power supplies, battery simulators, and servo drives.

Description

Technical Field

[0001] This invention relates to the technical field of power supplies, and in particular to a bidirectional current smooth switching system, method, and dual-quadrant power supply with no crossover distortion. Background Technology

[0002] In the fields of power electronics, precision testing, and automation control, dual-quadrant power supplies are key devices capable of providing bidirectional positive and negative output current. They are widely used in scenarios such as battery simulation, motor drive testing, audio power amplification, and material property analysis. These applications require the output current to switch rapidly and accurately between positive and negative directions, maintaining continuity, smoothness, and distortion-free operation near zero crossings to realistically simulate actual operating conditions or avoid impacting sensitive loads. A common solution uses relays or semiconductor switch arrays for hardware commutation. However, this method inevitably has a current interruption dead zone during switching, failing to achieve truly continuous and smooth transitions, and also suffers from slow response speed and limited lifespan. Another widely adopted approach is based on Class B or traditional Class AB push-pull power amplifier circuits. Although such structures support bidirectional output, when the output current crosses zero, due to the turn-on threshold voltage and switching delay of the power transistor, a typical "crossover distortion" phenomenon occurs. That is, the current waveform is distorted, dipped, or nonlinearly discontinuous near the zero point. This not only seriously affects the accuracy and fidelity of the output signal, but also limits the application of the system in precision control applications. Although pure Class A amplifiers can avoid crossover distortion, their extremely low efficiency and high heat loss make them impractical for high-power applications.

[0003] Therefore, there is an urgent need for a bidirectional current smoothing switching technology that can balance high efficiency, high speed and high fidelity to solve the problems of crossover distortion, dead zone or low efficiency in existing solutions during zero-crossing switching. Summary of the Invention

[0004] The main objective of this invention is to provide a bidirectional current smooth switching system, method, and dual-quadrant power supply without crossover distortion. The dynamically biased ClassAB push-pull output unit provides static micro-conduction bias for the N-type and P-type power transistors in the push-pull output unit through its internal bias sub-unit. Combined with closed-loop control, this enables the system output current to transition continuously and smoothly when switching between positive and negative zero points, completely eliminating the crossover distortion and switching dead zone problems existing in traditional bidirectional power supplies.

[0005] To achieve the above objectives, the present invention provides a bidirectional current smoothing switching system without crossover distortion, comprising:

[0006] The signal setting unit is used to provide the target electrical signal;

[0007] The feedback sampling unit is used to acquire the voltage or current of the load and generate a feedback signal;

[0008] The control processing unit is connected to the signal setting unit and the feedback sampling unit respectively, and is used to generate a drive signal based on the error between the target electrical signal and the feedback signal;

[0009] The dynamically biased Class AB push-pull output unit includes a bias subunit and a push-pull output subunit composed of N-type power transistors and P-type power transistors.

[0010] The bias subunit is connected to the push-pull output subunit and is used to provide bias for the N-type power transistor and the P-type power transistor, so that the N-type power transistor and the P-type power transistor are both in a micro-conducting state when static.

[0011] The control terminal of the push-pull output subunit is connected to the control processing unit to receive the drive signal. The output terminal of the push-pull output subunit is used to connect to the load and to provide bidirectional current to the load according to the drive signal, so that the output current can achieve a smooth transition without crossover distortion when crossing zero in the positive and negative directions.

[0012] Furthermore, the dynamic bias ClassAB push-pull output unit includes a bias subunit and a push-pull output subunit;

[0013] The push-pull output subunit includes an N-type power transistor and a P-type power transistor. The controlled terminal of the N-type power transistor and the controlled terminal of the P-type power transistor are connected together to form a first control node. The output terminal of the N-type power transistor and the output terminal of the P-type power transistor are connected together to form the output terminal of the bidirectional current smooth switching system without crossover distortion.

[0014] The bias subunit is connected to the push-pull output subunit. The bias subunit includes a current mirror circuit or a floating current source circuit, which is used to provide bias current or bias voltage to the N-type power transistor and the P-type power transistor, so that the gate-source voltage of the N-type power transistor is higher than its threshold voltage, and the absolute value of the gate-source voltage of the P-type power transistor is higher than the absolute value of its threshold voltage, so that the N-type power transistor and the P-type power transistor are both in a micro-conduction state when static.

[0015] Furthermore, the control processing unit includes an error amplifier;

[0016] The first input terminal of the error amplifier receives a signal from the signal setting unit, the second input terminal receives the feedback signal from the feedback sampling unit, and the output terminal of the error amplifier is connected to the first control node.

[0017] Furthermore, the feedback sampling unit includes a differential amplifier, the input of which is connected across a sampling resistor connected in series in the load circuit.

[0018] Furthermore, the signal setting unit includes a digital-to-analog converter for converting digital setting values ​​into the target electrical signal.

[0019] The present invention also provides a bidirectional current smoothing switching method without crossover distortion, comprising:

[0020] Dynamic bias is provided so that the N-type power transistors and P-type power transistors in the push-pull output subunit are in a slightly on state when there is no signal;

[0021] Acquire the target electrical signal and the feedback signal, wherein the feedback signal is a voltage or current signal acquired by the feedback sampling unit;

[0022] A drive signal is generated based on the error between the target electrical signal and the output feedback signal;

[0023] The push-pull output subunit is controlled according to the drive signal to output current to the load;

[0024] The output current achieves smooth switching without crossover distortion when it crosses zero in both positive and negative directions.

[0025] Furthermore, the step of providing dynamic bias specifically includes:

[0026] A current mirror circuit or a floating current source circuit is used to provide static bias for the N-type power transistor and the P-type power transistor.

[0027] The present invention also provides a dual-quadrant power supply, which deploys the crossover-distortion-free bidirectional current smoothing switching system described in any of the above embodiments, and performs the crossover-distortion-free bidirectional current smoothing switching method described in the above embodiments.

[0028] Furthermore, the dual-quadrant power supply is applied in a battery testing system as a battery simulator; wherein, the output terminal of the dual-quadrant power supply is used to connect to the test channel of the battery management testing device.

[0029] The present invention also provides an electronic device, which is deployed in the above-described dual-quadrant power supply through the above-described crossover-distortion-free bidirectional current smoothing switching system, and performs the above-described crossover-distortion-free bidirectional current smoothing switching method.

[0030] This invention provides a bidirectional current smooth switching system, method, and dual-quadrant power supply with no crossover distortion, offering the following advantages: By introducing a precise dynamic bias design for the Class AB push-pull output unit, the N-type and P-type power transistors in the output stage are in an optimized micro-conduction state in the static state. When the output current crosses zero, the operating states of the two transistors are seamlessly connected, fundamentally avoiding waveform distortion and interruptions caused by turn-on delay or dead-zone voltage. This achieves a truly continuous, smooth, and distortion-free transition of current between the positive and negative directions, resulting in significantly lower power consumption than a pure Class AB amplifier when outputting large currents. Simultaneously, its static power consumption is effectively controlled through optimized dynamic bias, achieving an optimal balance between efficiency and linearity while ensuring high performance without crossover distortion. By eliminating the need for external control logic for "stop-commutation" operations, the system has a fast dynamic response speed and can accurately reproduce rapidly changing command signals, making it particularly suitable for testing and driving scenarios with high transient response requirements. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the bidirectional current smooth switching system without crossover distortion in an embodiment of the present invention.

[0032] Figure 2 This is a simulation waveform diagram after applying this method in an embodiment of the present invention;

[0033] Figure 3 This is a simulation waveform diagram before applying the method in this embodiment of the invention;

[0034] Figure 4 This is a flowchart of the bidirectional current smoothing switching method without crossover distortion in an embodiment of the present invention;

[0035] Figure 5 This is a framework diagram of a bidirectional current smoothing switching unit without crossover distortion in an embodiment of the present invention;

[0036] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0038] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0039] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0040] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0041] Reference Figure 5 The diagram shows the unit framework of a bidirectional current smoothing switching system without crossover distortion according to an embodiment of the present invention. The system mainly includes: a signal setting unit, a control processing unit, a dynamic bias ClassAB push-pull output unit, a feedback sampling unit, and a load.

[0042] The output of the signal setting unit is connected to the first input of the control processing unit to provide a target electrical signal V_set, which can be a target voltage value or a target current value, determining the final output state of the system. In some embodiments, the signal setting unit may include a digital-to-analog converter (DAC) to convert digital instructions from an external controller (such as an MCU) into a high-precision analog voltage signal V_set. The input of the feedback sampling unit is connected to the output of the system to acquire the output voltage V_out across the load or the output current I_out flowing through the load in real time and generate a corresponding feedback signal V_fb. The output of the feedback sampling unit is connected to the second input of the control processing unit. In a preferred embodiment, when the system operates in constant current mode, the feedback sampling unit includes a differential amplifier whose input is connected across a precision sampling resistor R_sense connected in series in the output circuit, thereby converting the output current I_out into a proportional voltage signal V_fb. The control processing unit receives the target electrical signal V_set and the feedback signal V_fb, and generates a drive signal V_drive based on the error between the two. The output of the control processing unit is connected to the control terminal of the dynamically biased ClassAB push-pull output unit. In some embodiments, the control processing unit can be specifically implemented as an error amplifier. The control processing unit includes an error amplifier OP1. The non-inverting input of the error amplifier OP1 receives V_set provided by the signal setting unit, and its inverting input receives V_fb provided by the feedback sampling unit. The error amplifier OP1 amplifies the error voltage difference between V_set and V_fb and generates the drive signal V_drive at its output. This closed-loop control structure ensures that the system output can quickly and accurately track the set value. The dynamically biased ClassAB push-pull output unit specifically includes a bias subunit and a push-pull output subunit. Its input receives the drive signal V_drive from the control processing unit, and its output is connected to the load. The push-pull output subunit adopts a complementary symmetric structure, including an N-type power transistor MN1 and a P-type power transistor MP1. The drain of the N-type power transistor MN1 is connected to the positive power supply VDD, and its source is shared with the source of the P-type power transistor MP1, forming the system's output node V_out, used to drive the load. The drain of the P-type power transistor MP1 is connected to the negative power supply VSS or ground. The gates of MN1 and MP1 are shared, forming the first control node, which receives the drive signal V_drive. The bias subunit is connected to the push-pull output subunit. Its core function is to provide precise dynamic bias for MN1 and MP1, so that both are in a micro-conduction state when there is no signal or a small signal, thereby eliminating the crossover distortion inherent in traditional Class B or poorly biased Class AB circuits.In some embodiments, the bias subcell can take various implementations. For example, in a preferred embodiment, the bias subcell can be a current mirror circuit composed of matched transistors. This current mirror generates one or more stable bias currents, which, through appropriate current injection networks, provide small bias voltages to the gate-source loops of MN1 and MP1, respectively, ensuring that they always operate near the weak inversion region critical point close to conduction. In another alternative embodiment, the bias subcell can also be a floating current source structure connected across the gates of MN1 and MP1 or the relevant bias nodes to provide dynamic bias voltages in a similar manner. Furthermore, the current mirror circuit can be implemented using common topologies such as the basic type, Wilson current mirror, or wide swing current mirror. Its core is to provide a stable bias current with low correlation to power supply voltage and temperature changes. The floating current source can also be implemented by a servo loop composed of operational amplifiers and transistors. These specific circuits are all well-known technologies in the field. Their key role in this invention is to set the static operating points of MN1 and MP1 in the weak inversion region by providing the aforementioned precise bias amount. This is a necessary condition for achieving smooth switching without crossover distortion.

[0043] The working principle of the crossover-distortion-free bidirectional current smooth switching system in this embodiment of the invention is described below:

[0044] like Figure 1As shown, after the system is powered on, each unit starts working. The bias subunit in the dynamic bias ClassAB push-pull output unit starts immediately. The core task of this subunit is to generate a stable reference bias that is related to temperature and power supply voltage. This reference bias is applied to the control loops of the N-type power transistor (MN1) and P-type power transistor (MP1) in the push-pull output subunit. By precisely setting their design values, the gate-source voltages of MN1 and MP1 are slightly higher or slightly lower than their threshold voltages. In this state, neither MN1 nor MP1 enters the fully conducting strong inversion region, so the quiescent current flowing through them is usually in the microampere range, effectively controlling the quiescent power consumption. However, neither transistor is turned off, and their transconductance has a very small but non-zero finite value near zero. At this time, if the load is open, the voltage of the output node V_out will stabilize at a certain quiescent potential determined by the bias and power supply voltage. When the signal setting unit provides a target electrical signal V_set, the system enters the dynamic closed-loop regulation stage. The feedback sampling unit continuously monitors the voltage or current of the output node V_out and generates a feedback signal V_fb. The control processing unit is a high-gain error amplifier that compares the V_set received at its non-inverting input with the V_fb received at its inverting input. Any error voltage between V_set and V_fb is amplified by OP1. The output of the error amplifier OP1 generates a drive signal V_drive, which is directly applied to the first control node of MN1 and MP1.The drive signal V_drive is adjusted and output through two modes: the source mode provides a positive current. When the system needs to raise V_out, for example, when V_set > V_fb, the V_drive voltage output by OP1 rises. For the N-type power transistor MN1, the increase in V_drive causes its Vgs to increase, and the conduction degree deepens further from the slightly conductive state, and the channel resistance decreases, so that more current can be drawn from the positive power supply VDD to the load. For the P-type power transistor MP1, the increase in V_drive causes its Vgs to decrease, and the conduction degree weakens from the slightly conductive state towards the cut-off direction, and its equivalent resistance increases. At this time, MN1 serves as the main switching transistor, and MP1 serves as the auxiliary transistor. The current path is: VDD → MN1 → output node V_out → load → ground, and the system provides a positive current I_out > 零 to the load; the well mode absorbs a negative current. When the system needs to lower V_out, such as when V_set < V_fb, the V_drive voltage output by OP1 drops. For the P-type power transistor MP1, the decrease in V_drive causes its Vsg to increase, and the conduction degree deepens further from the slightly conductive state, and it can absorb the current on the load to the negative power supply VSS or ground. For the N-type power transistor MN1, the decrease in V_drive causes its Vgs to decrease, and the conduction degree weakens from the slightly conductive state towards the cut-off direction. At this time, MP1 serves as the main switching transistor, and MN1 serves as the auxiliary transistor. The current path is: load → output node V_out → MP1 → VSS, and the system absorbs current from the load, that is, provides a negative current I_out < 零. When the target signal V_set changes and requires the output current I_out to cross zero from positive to negative or from negative to positive, in a traditional Class B or poorly biased Class AB circuit, when I_out approaches zero, one of the power transistors has been completely turned off, and the other power transistor has not been turned on yet. The drive signal V_drive must change sufficiently large to overcome the dead zone voltage in order to turn on the other transistor, resulting in a "platform" or "step" in the current waveform at zero, that is, crossover distortion. In the present invention, since MN1 and MP1 are biased in the slightly conductive state at static, they are never completely turned off during the entire working cycle. When V_drive changes smoothly and drives the output current to pass through zero, at the end of the positive current stage, the conduction degree of MN1 gradually weakens, and the conduction degree of MP1 gradually increases. At the moment when the current passes through zero, both MN1 and MP1 operate in the region where the transconductance gm after superposition of their transfer characteristic curves is still continuous and non-zero. The transfer of current control from MN1 to MP1 is a seamless and linear交接 process. Subsequently, at the beginning of the negative current stage, the conduction degree of MP1 continues to deepen and becomes the dominant, and MN1 further weakens. Therefore, the output current I_out is a continuous and monotonic function of the drive signal V_drive, and its waveform is smooth at the zero crossing point, and the first derivative is continuous, achieving a truly "crossover distortion-free" switching. Figure 2 The simulation waveform curve of Figure 3 The distorted waveform diagram of the traditional scheme shown presents a stark contrast.

[0045] The entire system forms a typical voltage or current mode negative feedback loop. Any output deviation caused by load changes, power supply disturbances, or temperature drift will be corrected in real time and automatically through the closed-loop path of "feedback sampling → error comparison → drive adjustment → power output". The bias sub-unit ensures that the micro-conduction operating points of MN1 and MP1 remain relatively stable even under environmental changes, thereby always maintaining the ability to eliminate crossover distortion.

[0046] The system described in this invention, through the collaboration of the dynamically biased ClassAB push-pull output unit and the closed-loop control unit, can perfectly adapt to various scenarios requiring high-precision, high-speed bidirectional current control. For example, when used as a precision programmable power supply or battery simulator: in source mode outputting positive current, the drive signal V_drive output by the control processing unit increases the conduction level of the N-type power transistor MN1, enabling precise power supply or charging of the device under test (DUT), with smooth current control and no overshoot; in sink mode outputting negative current, the drive signal V_drive increases the conduction level of the P-type power transistor MP1, precisely absorbing energy from the DUT, achieving seamless discharge or load simulation. This invention employs a dynamically biased Class AB push-pull structure as the core power stage, achieving an ultimate balance of performance. This structure inherits the high efficiency of Class B / AB push-pull circuits while introducing zero-crossing distortion linearity, a feature typically found only in Class A amplifiers, through innovative dynamic biasing technology. This combination allows the system to maintain excellent waveform fidelity across the entire range from full-power output to minute current switching, resolving the inherent trade-off between efficiency and linearity in traditional solutions. Furthermore, since the output stage transistors are always in a slightly active state, the current direction switching is a result of continuous changes in the transconductance of the devices, rather than a sudden change in the switching state. Therefore, the system's response to commands is essentially a high-speed linear amplification process, with its switching speed limited only by the slew rate and loop bandwidth of the error amplifier OP1. Seamless zero-crossing switching at the microsecond or even nanosecond level can be achieved, far exceeding solutions relying on mechanical relays or digital algorithms. The dynamic biasing can be reliably implemented using mature analog circuit technologies such as current mirrors and floating current sources.

[0047] It should be noted that the embodiments of the present invention are not limited to the specific circuit parameters shown in the accompanying drawings. The specific implementation of the bias subunit can be various forms of current source or voltage source network, as long as it can provide a stable micro-conduction bias for the output transistor. The power transistor type of the push-pull output subunit, such as MOSFET, BJT, and device size, can be selected and optimized according to the required current, voltage, and speed levels. The feedback sampling unit can be configured as a single voltage sampling, a single current sampling, or a voltage-current composite sampling as needed to support various operating modes such as constant voltage and constant current. The dynamically biased Class AB push-pull output unit can be used as a standard power unit. In practical applications, multiple such power units can be connected in parallel and share the same set of control processing unit and feedback sampling unit to achieve linear superposition of output power, thereby constructing a dual-quadrant power supply system from watts to kilowatts and even higher power to meet the power requirements of different occasions.

[0048] refer to Figure 4 As shown, the present invention also relates to a bidirectional current smoothing switching method without crossover distortion, comprising the following steps:

[0049] S1 provides dynamic bias, enabling the N-type and P-type power transistors in the push-pull output stage to be in a slightly on state when there is no signal.

[0050] S2, acquire the target electrical signal and the output feedback signal of the system;

[0051] S3, generate a drive signal based on the error between the target electrical signal and the output feedback signal;

[0052] S4, control the push-pull output stage according to the drive signal to output current to the load; wherein, when the output current crosses zero in the positive and negative directions, a smooth switching without crossover distortion is achieved.

[0053] As described in step S1 above, after the system is powered on, the bias sub-unit in the dynamically biased ClassAB push-pull output unit begins to work. This bias sub-unit generates a stable bias voltage or current and applies it to the control terminals of the N-type power transistor MN1 and the P-type power transistor MP1 in the push-pull output sub-unit, so that the gate-source voltages of MN1 and MP1 are precisely set at a critical point slightly higher than their threshold voltages. Thus, MN1 and MP1 maintain a weak inversion region, i.e., a micro-conduction state, when there is no external drive signal. The static current flowing through them is extremely small, but the transconductance gm of both is not zero near the zero point. The establishment of this state lays the physical foundation for the smooth switching of the current without crossover distortion.

[0054] As described in step S2 above, a target electrical signal V_set is received or generated by the signal setting unit. At the same time, the output voltage V_out or output current I_out applied to the load by the system output terminal is collected in real time by the feedback sampling unit and converted into a feedback signal V_fb.

[0055] As described in step S3 above, the error between the target electrical signal V_set and the feedback signal V_fb is calculated by the control processing unit. Based on the error, a drive signal V_drive is generated and output in real time to the common gate of MN1 and MP1 of the dynamic bias ClassAB push-pull output unit.

[0056] As described in step S4 above, the drive signal V_drive is applied to the first control nodes of MN1 and MP1 in the push-pull output subunit to continuously and linearly adjust their conduction levels. When a positive current needs to be output, V_drive increases, causing MN1 to conduct more deeply, changing from a slightly conducting state to a strongly conducting state, while MP1 conducts less deeply, and the current flows from the positive power supply through MN1 to the load. When a negative current needs to be output, V_drive decreases, causing MP1 to conduct more deeply, while MN1 conducts less deeply, and the current flows from the load through MP1 to the negative power supply or ground.

[0057] In one embodiment, step S1, which provides a dynamic bias to enable the N-type and P-type power transistors in the push-pull output stage to be in a slightly on state when there is no signal, includes:

[0058] S11, enable the bias sub-unit in the dynamically biased ClassAB push-pull output unit;

[0059] S12, the bias subunit generates a stable bias reference value;

[0060] S13, the bias reference is applied to the control loops of the N-type power transistor and the P-type power transistor, so that both establish and maintain a static micro-conduction state.

[0061] In specific implementation, after the bias subunit is powered on, the current mirror circuit or floating current source circuit of its internal circuit starts to work, generating a stable bias current or voltage related to temperature and power supply voltage as the bias reference quantity. This reference quantity is fed to the gate or related bias node of N-type power transistor MN1 and P-type power transistor MP1 respectively, and its gate-source voltage Vgs is precisely set to be slightly higher than the threshold voltage Vth so that it operates in the weak inversion region. At this time, the static current flowing through MN1 and MP1 is in the microampere level. While effectively controlling the static power consumption, it ensures that the transconductance gm of the two transistors is a continuous non-zero value near the zero point, thereby laying the foundation for eliminating crossover distortion in the subsequent current switching process.

[0062] In one embodiment, step S2, which involves acquiring the target electrical signal and the system's output feedback signal, includes:

[0063] S21, the target electrical signal is generated or received by the signal setting unit;

[0064] S22, the system's output voltage or output current is collected in real time through the feedback sampling unit, and the output feedback signal is generated.

[0065] In specific implementation, the target electrical signal V_set can be generated by an internal reference source or set and input by an external controller MCU through a digital-to-analog converter (DAC). It represents the voltage or current limit value that the system expects to output. At the same time, the feedback sampling unit continues to work: if the system is operating in constant voltage mode, it directly samples the output node voltage through a resistor divider network; if it is operating in constant current mode or current monitoring is required, it measures the small voltage difference across the sampling resistor connected in series in the output circuit through a high-precision differential amplifier and amplifies it into the output feedback signal V_fb. This process ensures that the system's perception of the actual output state is real-time, accurate, and has the same dimensions as the set value, providing accurate input for subsequent error comparison and control.

[0066] In one embodiment, step S3, which generates a drive signal based on the error between the target electrical signal and the output feedback signal, includes:

[0067] S31, the target electrical signal and the output feedback signal are respectively input to the error amplifier of the control processing unit;

[0068] S32, the error amplifier compares and amplifies the two input signals and outputs an error voltage;

[0069] S33, the error voltage is output as the drive signal to the control node of the push-pull output stage.

[0070] In specific implementation, the error amplifier of the control processing unit, such as error amplifier OP1, constitutes a high-gain negative feedback comparator. Its non-inverting input receives the target electrical signal V_set from the signal setting unit, and its inverting input receives the output feedback signal V_fb from the feedback sampling unit. The error amplifier continuously adjusts its error voltage through its high open-loop gain, so that the potential difference between its two input terminals tends to zero, thereby forcing V_fb to track V_set in real time. This dynamically adjusted output voltage is the drive signal V_drive used to directly control the power output stage. This process realizes precise closed-loop adjustment between the system output and the target setting, ensuring system stability, accuracy, and fast response capability.

[0071] In one embodiment, the push-pull output stage is controlled according to the drive signal to output current to the load; wherein step S4, which achieves smooth switching without crossover distortion when the output current crosses zero in the positive and negative directions, includes:

[0072] S41, the drive signal is applied to the common control terminal of the N-type power transistor and the P-type power transistor to synchronously adjust their conduction levels;

[0073] S42, in response to the polarity change of the drive signal, controls the push-pull output stage to switch between the source mode with positive output current and the sink mode with negative output current.

[0074] S43, during the current direction conversion, based on the micro-conduction state of the power transistor, its transconductance changes continuously, achieving a smooth and seamless transition of the output current zero-crossing point.

[0075] In specific implementation, the drive signal V_drive directly drives the complementary push-pull pair composed of MN1 and MP1. When the V_drive voltage increases, the Vgs of MN1 increases, enhancing its conduction, and the dominant current flows from the power supply through the load to ground; when the V_drive voltage decreases, the Vsg of MP1 increases, enhancing its conduction, and the dominant current flows from the load through ground to the power supply. The key is that, due to the static micro-conduction bias established in step S1, MN1 and MP1 do not enter the complete cutoff region throughout the entire dynamic operation. Therefore, when the output current crosses zero due to the change in V_drive, the conduction states of the two transistors continuously and linearly increase and decrease, and the sum of their transconductances gm remains continuously non-zero at the zero-crossing point. The current control is seamlessly transferred between the two transistors, making the output current waveform a continuous monotonic function of the drive signal, smooth and distortion-free at the zero point, eliminating the crossover distortion caused by turn-on delay and dead-time voltage in traditional schemes. Figure 2 As shown in the simulation waveform, this mechanism ensures that the system can complete high-fidelity switching of bidirectional current within microseconds.

[0076] The present invention also relates to a dual-quadrant power supply, including the bidirectional current smooth switching system without crossover distortion described in the above embodiments.

[0077] The present invention also relates to a battery testing system, including the dual-quadrant power supply of the above embodiments.

[0078] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the present invention and embodiments may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual-rate SDRAM (SSRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM, etc.

[0079] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0080] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A bidirectional current smoothing switching system without crossover distortion, characterized in that, include: The signal setting unit is used to provide the target electrical signal; The feedback sampling unit is used to acquire the voltage or current of the load and generate a feedback signal; The control processing unit is connected to the signal setting unit and the feedback sampling unit respectively, and is used to generate a drive signal based on the error between the target electrical signal and the feedback signal; The dynamically biased Class AB push-pull output unit includes a bias subunit and a push-pull output subunit composed of N-type power transistors and P-type power transistors. The bias subunit is connected to the push-pull output subunit and is used to provide bias for the N-type power transistor and the P-type power transistor, so that the N-type power transistor and the P-type power transistor are both in a micro-conducting state when static. The control terminal of the push-pull output subunit is connected to the control processing unit to receive the drive signal. The output terminal of the push-pull output subunit is used to connect to the load and to provide bidirectional current to the load according to the drive signal, so that the output current can achieve a smooth transition without crossover distortion when crossing zero in the positive and negative directions.

2. The crossover-distortion-free bidirectional current smoothing switching system according to claim 1, characterized in that, The dynamic bias ClassAB push-pull output unit includes a bias subunit and a push-pull output subunit; The push-pull output subunit includes an N-type power transistor and a P-type power transistor. The controlled terminal of the N-type power transistor and the controlled terminal of the P-type power transistor are connected together to form a first control node. The output terminal of the N-type power transistor and the output terminal of the P-type power transistor are connected together to form the output terminal of the bidirectional current smooth switching system without crossover distortion. The bias subunit is connected to the push-pull output subunit. The bias subunit includes a current mirror circuit or a floating current source circuit, which is used to provide bias current or bias voltage to the N-type power transistor and the P-type power transistor, so that the gate-source voltage of the N-type power transistor is higher than its threshold voltage, and the absolute value of the gate-source voltage of the P-type power transistor is higher than the absolute value of its threshold voltage, so that the N-type power transistor and the P-type power transistor are both in a micro-conduction state when static.

3. The crossover-distortion-free bidirectional current smoothing switching system according to claim 2, characterized in that, The control processing unit includes an error amplifier; The first input terminal of the error amplifier receives a signal from the signal setting unit, the second input terminal receives the feedback signal from the feedback sampling unit, and the output terminal of the error amplifier is connected to the first control node.

4. The crossover-distortion-free bidirectional current smoothing switching system according to claim 1, characterized in that, The feedback sampling unit includes a differential amplifier, the input of which is connected across a sampling resistor connected in series in the load circuit.

5. The crossover-distortion-free bidirectional current smoothing switching system according to claim 1, characterized in that, The signal setting unit includes a digital-to-analog converter for converting digital setting values ​​into the target electrical signal.

6. A bidirectional current smoothing switching method without crossover distortion, characterized in that, The method of performing the crossover-distortion-free bidirectional current smoothing switching system according to any one of claims 1-5 includes: Dynamic bias is provided so that the N-type power transistors and P-type power transistors in the push-pull output subunit are in a slightly on state when there is no signal; Acquire the target electrical signal and the feedback signal, wherein the feedback signal is a voltage or current signal acquired by the feedback sampling unit; A drive signal is generated based on the error between the target electrical signal and the feedback signal; The push-pull output subunit is controlled according to the drive signal to output current to the load; The output current achieves smooth switching without crossover distortion when it crosses zero in both positive and negative directions.

7. The crossover-distortion-free bidirectional current smoothing switching method according to claim 6, characterized in that, The step of providing dynamic bias specifically includes: A current mirror circuit or a floating current source circuit is used to provide static bias for the N-type power transistor and the P-type power transistor.

8. A dual-quadrant power supply, characterized in that, Deploy the bidirectional current smoothing switching system without crossover distortion as described in any one of claims 1 to 5, and perform the bidirectional current smoothing switching method without crossover distortion as described in claim 6 or 7.

9. The dual-quadrant power supply according to claim 8, characterized in that, The dual-quadrant power supply is used in the battery testing system as a battery simulator; wherein, the output terminal of the dual-quadrant power supply is used to connect to the test channel of the battery management testing device.

10. An electronic device, characterized in that, The crossover-distortion-free bidirectional current smoothing switching system described in any one of claims 1-5 is deployed in the dual-quadrant power supply described in claim 8 or 9 to perform the crossover-distortion-free bidirectional current smoothing switching method described in claim 6 or 7.

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