Power measurement in switch-mode power supplies

Abstract

A switch-mode power supply (SMPS) includes a filter, a power factor correction (PFC) circuit, and control circuitry configured to determine various electrical parameters of the SMPS. In some embodiments, the control circuitry is configured to determine a power line frequency and an AC input voltage based on an AC line voltage and an AC neutral voltage. In other embodiments, the control circuitry is configured to determine an AC input current based on a reactive current flowing through the filter and a PFC AC current. In still other embodiments, the control circuitry is configured to report the values ​​of the determined electrical parameters if they are accurate. Other example switch-mode power supplies, control circuitry, and methods are also disclosed.

Description

Technical Field

[0001] This disclosure relates to power measurement in switched-mode power supplies. Background Technology

[0002] This section provides background information relating to the contents of this disclosure.

[0003] AC-DC switch-mode power supplies (SMPS) typically include filters, power factor correction (PFC) circuitry, and control circuitry. The control circuitry calculates the SMPS's input current, input voltage, input power, etc., based on sensed parameters. Typically, SMPS employs power metering chips for measuring input current and voltage, and calculating input power, etc. Summary of the Invention

[0004] This section provides a general overview of this disclosure and is not a full disclosure of its entire scope or all of its features.

[0005] According to one aspect of this disclosure, an SMPS includes: a line rail; a neutral rail; a filter coupled between the line rail and the neutral rail and having an input for receiving an AC input voltage and an AC input current, an X capacitor, and an output; a PFC circuit coupled to the output of the filter and having an input for receiving a PFC AC current; and a control circuit coupled to the PFC circuit. The control circuit is configured to: generate an analog signal representing the difference between the AC line voltage and the AC neutral voltage; compare the analog signal with the defined threshold to determine zero crossings of the analog signal; determine the frequency of the AC input voltage or the AC input current based on at least two of the zero crossings of the analog signal; determine the reactive current flowing through the X capacitor in the filter based on the determined frequency; and determine the AC input current of the SMPS based on the determined reactive current and the PFC AC current.

[0006] According to another aspect of this disclosure, a method for determining the AC input current of a Smart Filtering System (SMPS) is disclosed. The SMPS includes: a linear rail; a neutral rail; a filter coupled between the linear rail and the neutral rail; and a power factor correction (PFC) circuit coupled to the output of the filter. The method includes: generating an analog signal representing the difference between an AC line voltage and an AC neutral voltage; comparing the analog signal with the defined threshold to determine zero-crossings of the analog signal; determining frequencies of either the AC input voltage or the AC input current based on at least two of the zero-crossings of the analog signal; determining a reactive current in the filter based on the determined frequencies; and determining the AC input current of the SMPS based on the determined reactive current and the PFC AC current.

[0007] According to another aspect of this disclosure, an SMPS includes: a linear rail; a neutral rail; a filter coupled between the linear rail and the neutral rail and having an input for receiving an AC input voltage and an AC input current; a PFC circuit coupled to the output of the filter; and a control circuit having a differential amplifier and a digital controller. The differential amplifier is configured to generate an analog signal representing the difference between the AC line voltage and the AC neutral voltage. The digital controller is configured to determine the frequency of the AC input voltage and the frequency of the AC input current based on the analog signal.

[0008] According to another aspect of this disclosure, an SMPS includes: a filter having an input, an X-capacitor, and an output for receiving AC input current; a PFC circuit coupled to the output of the filter; and a control circuit coupled to the PFC circuit. The control circuit is configured to: determine values ​​of AC input electrical parameters of the SMPS; estimate the values ​​of the AC input electrical parameters of the SMPS based on defined efficiency and output power of the SMPS; determine an average value of the AC input electrical parameters if the difference between the determined value and the estimated value of the AC input electrical parameters is less than a defined tolerance threshold; determine the accuracy of the determined values ​​of the AC input electrical parameters based on the average value of the AC input electrical parameters; and report the determined values ​​of the AC input electrical parameters to an external device if the accuracy of the determined values ​​of the AC input electrical parameters is less than a defined accuracy threshold.

[0009] According to another aspect of this disclosure, a method for reporting AC input electrical parameters of a Smart Filter System (SMPS) is disclosed. The SMPS includes a filter and a Power Factor Correction (PFC) circuit. The method includes: determining the value of the AC input electrical parameter of the SMPS; estimating the value of the AC input electrical parameter of the SMPS based on defined efficiency and output power of the SMPS; determining an average value of the AC input electrical parameter if the difference between the determined value and the estimated value of the AC input electrical parameter is less than the defined tolerance threshold; determining the accuracy of the determined value of the AC input electrical parameter based on the average value of the AC input electrical parameter; and reporting the determined value of the input electrical parameter to an external device if the accuracy of the determined value of the AC input electrical parameter is less than a defined accuracy threshold.

[0010] According to another aspect of this disclosure, an SMPS includes: a linear rail; a neutral rail; a filter coupled between the linear rail and the neutral rail; a PFC circuit coupled to the filter; a DC / DC power circuit coupled to the PFC circuit; and control circuitry. The filter includes an input for receiving AC input voltage and AC input current, an X capacitor, and an output. The PFC circuit includes an input for receiving PFC AC current, at least one power switch, and an output. The DC / DC power circuit includes at least one power switch and a transformer. The control circuitry is coupled to the PFC circuitry to control the at least one power switch of the PFC circuitry and is coupled to the DC / DC power circuitry to control the at least one power switch of the DC / DC power circuitry. The control circuitry includes at least one differential amplifier, a primary-side digital controller, a secondary-side digital controller, and an isolation device coupled between the primary-side digital controller and the secondary-side digital controller. The differential amplifier is configured to generate an analog signal representing the difference between the AC line voltage and the AC neutral voltage. The primary-side digital controller is configured to: determine the AC input voltage based on the analog signal, determine the frequency of the AC input voltage or the AC input current based on the analog signal, determine the reactive current flowing through the X capacitor based on the determined frequency, and determine the AC input current based on the determined reactive current and the PFC AC current.

[0011] Other aspects and areas of applicability will become apparent from the description provided herein. It should be understood that various aspects of this disclosure may be implemented individually or in combination with one or more other aspects. It should also be understood that the description and specific embodiments herein are intended for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0012] The accompanying drawings described herein are merely illustrative of the selected embodiments and not all possible implementations, and are not intended to limit the scope of this disclosure.

[0013] Figure 1 This is a flowchart of a method for determining the AC input current of an SMPS according to an example embodiment of the present disclosure.

[0014] Figure 2 This is an illustration of the zero-crossing curve of the signal used to determine the power line frequency, based on another example implementation.

[0015] Figure 3 This is a block diagram of an SMPS including filters, PFC circuitry, and control circuitry, according to yet another example implementation.

[0016] Figure 4 This is a schematic diagram of an SMPS including a filter, PFC circuit, DC / DC power converter, and control circuit according to another example implementation.

[0017] Figure 5 This is an example based on yet another example implementation scheme. Figure 4 The waveforms of the inductor current and input current of the SMPS are shown in the graph.

[0018] Figure 6 This is an example based on another example implementation. Figure 4 The waveforms of the reactive current and input current of the SMPS are shown in the graph.

[0019] Figure 7 This is an example of a different implementation scheme used to determine Figure 4 The graph shows the calculated input power value and the actual input power value of the SMPS for the offset error and gain error of the analog-to-digital converter (ADC) in the control circuit.

[0020] Figure 8 This is a block diagram of an SMPS including a filter, bridge rectifier, PFC circuit, DC / DC power converter, and control circuit according to another example implementation.

[0021] Figure 9 This is a flowchart of a method for reporting AC input electrical parameters of SMPS according to yet another example implementation.

[0022] Figure 10 This is a flowchart of a method for calibrating and reporting the AC input power of SMPS according to another example implementation.

[0023] Figure 11This is a flowchart of a method for calibrating and reporting the AC input current of SMPS according to yet another example implementation.

[0024] In all of the views in the accompanying drawings, corresponding reference numerals indicate corresponding (but not necessarily identical) parts and / or features. Detailed Implementation

[0025] The provision of exemplary embodiments makes this disclosure thorough and will fully communicate the scope to those skilled in the art. Numerous specific details, such as embodiments of specific components, apparatus, and methods, are set forth to provide a thorough understanding of embodiments of this disclosure. It will be apparent to those skilled in the art that specific details are not necessary, exemplary embodiments may be embodied in many different forms, and should not be construed as limiting the scope of this disclosure. In some exemplary embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

[0026] The terminology used herein is for the purpose of describing specific exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may also be intended to include the plural forms unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having” are inclusive and therefore specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or illustrated unless explicitly identified as such. It should also be understood that additional or alternative steps may be employed.

[0027] When an element or layer is referred to as “on another element or layer,” “joined to,” “connected to,” or “coupled to” another element or layer, it can be directly on, joined to, connected to, or coupled to another element or layer, or there may be intermediate elements or layers present. Conversely, when an element is referred to as “directly on another element or layer,” “directly joined to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” vs. “directly between,” “adjacent” vs. “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0028] Although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or part from another. Terms such as “first,” “second,” and other numerical terms, when used herein, do not imply a first order or sequence unless the context explicitly indicates otherwise. Therefore, without departing from the teachings of the example embodiments, the first element, component, region, layer, or part discussed below may be referred to as the second element, component, region, layer, or part.

[0029] For ease of description, this document may use spatial relative terms such as “inside,” “outside,” “below,” “below,” “lower,” “above,” “upper,” etc., to describe the relationship of one element or feature to another, as illustrated in the accompanying drawings. In addition to the orientations depicted in the drawings, spatial relative terms may be intended to encompass different orientations of the device in use or operation. For example, if the device in the drawings is flipped, an element described as “below” or “below” other elements or features will be oriented “above” said other elements or features. Thus, the illustrative term “below” may encompass both an orientation “above” and an orientation “below.” The device may be oriented in other ways (rotated 90 degrees or otherwise) and the spatial relative descriptions used herein shall be interpreted accordingly.

[0030] The example implementation will now be described more fully with reference to the accompanying drawings.

[0031] A method for determining the AC input current of an SMPS including a filter and PFC circuitry, according to an example embodiment of this disclosure, is illustrated. Figure 1 And generally indicated by the reference number 100. For example... Figure 1 As shown, method 100 includes: generating an analog signal representing the difference between the AC line voltage and the AC neutral voltage in the SMPS in block 102; comparing the analog signal with a defined threshold in block 104 to determine the zero crossings of the analog signal; determining a power line frequency (e.g., the frequency of the AC input voltage and / or the AC input current) based on at least two of the zero crossings of the analog signal in block 106; determining a reactive current flowing in the filter based on the determined frequency in block 108; and determining the AC input current of the SMPS based on the determined reactive current and the PFC AC current in block 110.

[0032] By identifying the zero-crossing of the analog signal, the power line frequency of the SMPS can be accurately calculated. This power line frequency is used to determine the AC input current, as explained further below. Thus, accurate determination of the power line frequency ensures that the determined input current is accurate. Because the input current is accurately determined, current sensing devices such as conventional power metering devices (e.g., power meter chips) used to monitor input parameters such as the AC input current are unnecessary.

[0033] As explained above, the AC input current is determined based on the PFC AC current and the reactive current. For example, Figure 2 An SMPS 200 is illustrated, comprising a linear rail L, a neutral rail N, a filter 202 coupled between the linear rail L and the neutral rail N for receiving the AC input current i_in, and a PFC circuit 204 coupled to the output of the filter 202. The filter 202 (e.g., an electromagnetic interference (EMI) filter) includes one or more X capacitors coupled between the linear rail L and the neutral rail N. For computational purposes, these one or more X capacitors can be combined to form the equivalent X capacitance C_eq of the filter 202. These X capacitors provide a path for the reactive current i_c to flow between the linear rail L and the neutral rail N. Thus, the current i_pfc supplied to the PFC circuit 204 need not be equal to the AC input current i_in. Therefore, when determining the AC input current i_in, the reactive current i_c flowing through the X capacitors of the filter should be compensated.

[0034] Return to reference Figure 1 The power line frequency can be determined based on at least two zero-crossings of an analog signal representing the difference between the AC line voltage and the AC neutral voltage. For example, Figure 3 A graph 300 is illustrated, comprising an analog signal 302 and a square wave signal 304. As explained above, the analog signal 302 represents the difference between the AC line voltage and the AC neutral voltage. In some embodiments, the analog signal 302 may be generated using a single differential amplifier, as further explained below.

[0035] The square wave signal 304 can be generated based on a comparison between the analog signal 302 and a defined threshold. For example, a comparator can be used to generate the square wave signal 304. In such an embodiment, the comparator can output a high or low signal when the analog signal 302 is equal to, greater than, less than, etc., the defined threshold. After this, the comparator can be reset. This creates various rising and falling edges of the square wave signal 304.

[0036] The defined threshold can be a zero-crossing of the analog signal 302. For example, the defined threshold can be equal to zero. In other embodiments, if the analog signal is shifted to prevent it from falling below zero, the defined threshold can be another suitable positive value. This may be necessary if a digital controller (e.g., a digital signal processor (DSP)) is used to process information and calculate power line frequencies. Figure 3 In a specific embodiment, the analog signal is shifted by 1.65 V (e.g., half of the 3.3 DSP voltage), and thus the threshold is defined as 1.65 V.

[0037] The rising and / or falling edges of the square wave signal 304 can correspond to the zero-crossing of an analog signal. For example, in Figure 3 In a specific embodiment, each rising edge and each falling edge of the square wave signal 304 corresponds to a zero crossing of the analog signal (e.g., 1.65 V). In other embodiments, only rising edges or only falling edges may correspond to zero crossings.

[0038] exist Figure 3 In some embodiments, the power line frequency can be determined based on two consecutive zero crossings. For example, when two consecutive zero crossings are used to determine the frequency f, the time interval (t) between the two consecutive zero crossings can be half the period (T) of the main power supply. Equation (a) can be rearranged into equation (b) to solve for the frequency (f). In equation (b) above, the time interval (t) can be measured, determined, etc., by, for example, an edge-interruption mechanism in a control circuit (e.g., any of the control circuits disclosed herein).

[0039]

[0040]

[0041] In some embodiments, the power line frequency of the power supply can vary from 47 Hz to 63 Hz. This variation in frequency can affect the impedance in the power supply—such as the impedance to the power source. Figure 2 The X capacitor C_eq of filter 202 in the filter has a significant impact. For example, Figure 2 The capacitive reactance of capacitor X, C_eq, is 1 / (2*pi*f*C). This capacitive reactance affects the reactive current i_c. Thus, by determining the precise value of the electric field frequency (f), the reactive current ic can be accurately calculated (as explained further below). Therefore, the input current i_in can be precisely determined.

[0042] Furthermore, the electric field frequency (f) explained above determines adaptive frequency changes. For example, if the unknown electric field frequency (f) of the input voltage changes, the zero-crossing of the analog signal will change accordingly. Consequently, the time interval (t) between two consecutive zero-crossings changes. Therefore, even if the electric field frequency (f) changes (e.g., between 47 Hz and 63 Hz), the frequency determination scheme explained above can accurately determine the value of the frequency (f).

[0043] The determined input current can be used in a variety of ways. For example, the determined input current can be used to calculate other electrical parameters of the SMPS (e.g., input power, etc.). In such embodiments, conventional power metering devices (e.g., power meter chips) for calculating input parameters are not necessary. Furthermore, the determined input current can be reported periodically, randomly, or continuously to an external device for monitoring purposes. In other embodiments, the determined input current can be used to control one or more power switches in the PFC circuit and / or other power conversion circuitry in the SMPS. In such embodiments, the determined input current can be used to increase the power factor of the SMPS.

[0044] The method described above for determining the AC input current can be implemented in any suitable control circuit—including, for example, any of the control circuits disclosed herein. For example, and as... Figure 2 As shown, the SMPS 200 includes a control circuit 206 coupled to the PFC circuit 204 for controlling at least one power switch 208 in the PFC circuit 204. Figure 2 As shown, control circuit 206 receives sensing signals 210 and 212 representing AC line voltage and AC neutral voltage, respectively. In some embodiments, control circuit 206 may generate an analog signal representing the difference between AC line voltage and AC neutral voltage (e.g., Figure 3 The control circuit 206 determines the AC input voltage and / or power line frequency of the SMPS 200 based on the analog signal 302. In some instances, the control circuit 206 may compare the analog signal with defined thresholds to determine the zero-crossings of the analog signal, and then determine the power line frequency based on at least two of the zero-crossings of the analog signal. In some embodiments, the control circuit may determine the reactive current i_c flowing through the X capacitor C_eq based on the determined frequency, and determine the AC input current of the SMPS 200 based on the determined reactive current i_c and the PFC AC current i_pfc, as explained above.

[0045] The control circuit 206 may include various components for determining the power line frequency, AC input voltage, AC input current i_in, etc. In some embodiments, the control circuit 206 may include one or more amplifiers, comparators, filters, controllers, etc., for determining the AC input current i_in. For example, Figure 4 An AC-DC SMPS 400 is illustrated, which includes control circuitry 406 comprising differential amplifiers 408, 410, comparator 412, filters 414, 416 (e.g., RC filters, etc.), and a digital controller 418 (e.g., a DSP). In other embodiments, control circuitry 406 may include a ratio Figure 4 More or fewer parts are shown. Figure 4 The control circuit 406 is Figure 2 An example implementation of the control circuit 206.

[0046] In some embodiments, the differential amplifier 408 may generate an analog signal representing the difference between the AC line voltage and the AC neutral voltage. In such embodiments, the digital controller 418 may determine the AC input voltage Vin_ac and the power line frequency (e.g., the frequency of the AC input voltage Vin_ac and / or the frequency of the AC input current i_in) based on the analog signal. In some embodiments, the control circuit 406 (e.g., the digital controller 418) may then determine the reactive current i_c, the AC input current i_in, the input power, etc. of the SMPS 400.

[0047] like Figure 4 As shown, the SMPS 400 also includes a filter 402 and an active PFC circuit 404 coupled to the output of the filter 402. As shown, the filter 402 is represented by an equivalent X capacitance C_eq coupled between the line rail L and the neutral rail N. Figure 4 In a specific embodiment, the PFC circuit 404 has a boost topology. Thus, the PFC circuit 404 includes an inductor L, a power switch Q, and a diode D arranged in a boost configuration. As shown, the power switch Q is an N-channel MOSFET. In other embodiments, another suitable topology and / or suitable switching device may be used if desired.

[0048] The power switch Q of the PFC circuit 404 can be controlled using PFC current loop control. For example, the control circuit 406 can receive the body voltage of the PFC circuit 404 via a voltage divider 424 and the inductor current iL via a differential amplifier 410 and a filter 416. The control circuit 406 can then generate a control signal using a driver 426 to control the power switch Q.

[0049] Furthermore, the SMPS 400 includes a DC / DC power converter 420 (e.g., a DC / DC power circuit) coupled to the output of the PFC circuit 404. The DC / DC power converter 420 may include any suitable converter topology, including, for example, a flyback converter, a forward converter (e.g., a two-transistor forward converter), a bulk converter, a boost converter, a bridge converter (e.g., a full-bridge, half-bridge, etc.), a resonant converter (e.g., an LLC converter, etc.), etc. Additionally, the DC / DC power converter 420 may include an isolated converter topology (e.g., with a transformer) or a non-isolated converter topology. In some embodiments, the DC / DC power converter 420 may include a synchronous rectifier on the secondary side of the isolation transformer.

[0050] Furthermore, the SMPS 400 may include a rectifier circuit for rectifying the AC input. For example, and as... Figure 4 As shown, the SMPS 400 includes a diode bridge rectifier 422 coupled between the filter 402 and the PFC circuit 404. In some embodiments, a high-frequency filter capacitor C may be coupled between the rectifier 422 and the PFC circuit 404, such as... Figure 4 As shown in the illustration. In other embodiments, other suitable rectifier circuits may be used if desired.

[0051] The input current i_in can be determined based on the inductor current iL supplied to the PFC circuit 404 and the reactive current i_c in the filter 402. The input current i_in is expressed as shown in equation (1) below.

[0052]

[0053] like Figure 4 As shown, the instantaneous value (e.g., RMS value) of the inductor current iL can be measured based on the voltage drop across the shunt resistor R1. This voltage drop signal is amplified by a single differential amplifier 410. The amplified signal is then fed via a filter 414 to a pin of the ADC in the digital controller 418. Figure 4 In a specific embodiment, the differential amplifier 410 includes an offset. For example, the differential amplifier 410 may include a voltage divider for shifting (e.g., offsetting) the output of the amplifier to ensure that the output is positive.

[0054] In such an embodiment, the inductor current iL can be determined based on the voltage (Vil.ADC) sampled by the ADC and provided by the differential amplifier 410 (e.g., the ADC counter value). For example, the value of the ADC after the output of the differential amplifier 410 has been converted can be determined using equation (2) below.

[0055]

[0056] In equation (2), R1 is the value of the shunt resistor, Gi is the gain of the differential amplifier 410, Voffset is the offset in the differential amplifier 410 as explained above, and ADCi is the interrupt bit of the ADC. The interrupt bit ADCi can be expressed as equation (3) below, where N is the number of bits of the ADC, and Vref is the reference voltage provided to the ADC.

[0057]

[0058] The inductor current iL can be calculated by rearranging equation (1), as shown in equation (4) below.

[0059]

[0060] In equation (4), the values ​​of Vref, N, R1, Gi, and Voffset are known based on the design of the SMPS 400. In such an embodiment, if the ADC is a 12-bit ADC (which is typical), the reference voltage Vref is 2.5 V, and Voffset / (R1×Gi) equals Ioffset, equation (4) can be simplified to equation (5) below.

[0061]

[0062] Equation (5) can be further simplified to Equation (6) below. In Equation (6), Ki equals 2.5 / 2^12*1 / Rs*Gi, A equals ViL.ADC, and B equals Ioffset. In such an embodiment, once the ADC counter value ViL.ADC is obtained by the digital controller 418, the inductor current iL can be obtained.

[0063]

[0064] The reactive current i_c can be determined based on the equivalent X capacitance C_eq, as shown in equation (7) below.

[0065]

[0066] In equation (7), Vc is the voltage across the equivalent X capacitor C_eq, and is determined based on equation (8) below. In equation (8), Vac(t) is the AC main input voltage, Vac is the measured value of the AC input voltage, and w is equal to 2×π(pi)×f (frequency).

[0067]

[0068] When equations (7) and (8) are combined, the reactive current i_c can be expressed as equation (9) below.

[0069]

[0070] For example, Figure 5 and Figure 6 Graphs 500 and 600 illustrate various waveforms of the analog current in the SMPS 400. Specifically, Figure 5 The graph 500 includes a current waveform 502 representing the inductor current iL(t) and a current waveform 504 representing the input current i_in(t). Figure 6 The graph 600 includes a current waveform 602 representing the reactive current i_c(t) and a current waveform 604 representing the input current i_in(t).

[0071] Graph 600 illustrates the effect of the reactive current i_c under light load conditions. For example, under light load conditions (e.g., 20% load and below), the input current i_in(t) (waveform 604) and the inductor current iL(t) (e.g., PFC current) are small. Thus, compared to larger loads, full loads, etc., the reactive current i_c(t) (waveform 602) can have a greater impact on the input current i_in(t). Therefore, if the reactive current i_c(t) cannot be accurately calculated, for example, under light load conditions, the input current i_in(t) (determined based on the reactive current) may not meet the desired accuracy criteria.

[0072] Return to reference Figure 4 The control circuit 406 uses a single differential amplifier 408 to determine the AC main input voltage and frequency (f). For example, and as... Figure 4 As shown, the differential amplifier 408 generates an analog signal representing the difference between the AC line voltage and the AC neutral voltage, as explained herein. This analog signal is provided to the digital controller 418 to obtain the AC main input voltage. For example, the instantaneous value (e.g., RMS value) of the AC main input voltage Vac can be determined based on equation (10) below.

[0073]

[0074] In equation (10), Vac.ADC represents the voltage (e.g., an analog signal) sampled by the ADC and supplied by the differential amplifier 408, R2 / (R1+R2) represents the voltage divider used to scale down the main voltage to a voltage level acceptable to the digital controller 418, N is the number of bits in the ADC, and Vref is the reference voltage supplied to the ADC. Furthermore, Z represents the voltage shift (e.g., 1.25 V) to accommodate the ADC voltage range (e.g., 2.5 V).

[0075] When the AC main input voltage is obtained, the control circuit 406 can determine the frequency (f). For example, and as... Figure 4 As shown, the analog signal generated by differential amplifier 408 is provided to comparator 412. Comparator 412 then uses the analog signal (e.g., Figure 3 The analog signal 302 is compared with a defined threshold, and a square wave signal for the digital controller 418 is generated based on this comparison. Figure 3 The square wave signal 304, as explained above, is used. The defined threshold is selected to ensure that the rising and / or falling edges of the square wave signal correspond to zero crossings of the analog signal (and therefore the AC main input voltage). The ADC in the digital controller 418 then calculates the power line frequency (f) based on the rising and falling edges (zero crossings) of the analog signal, as explained above.

[0076] The power line frequency (f) can be accurately calculated by generating an analog signal (AC main input voltage) using a single differential amplifier 408 and determining the precise zero-crossings using comparator 412. For example, and as explained herein, the frequency (f) is determined based on the zero-crossings of the analog signal (a single waveform) generated by the differential amplifier 408. In contrast, conventional methods determine the frequency based on multiple waveforms. Specifically, conventional methods determine the zero-crossings of the line voltage signal and the neutral voltage signal, and then determine the frequency based on the two sets of zero-crossings. Thus, any delay between the zero-crossings of the line voltage signal and the neutral voltage signal can cause inaccuracies in the determined frequency. However, in this disclosure, the power line frequency (f) can be accurately determined without this delay. Furthermore, the precise power line frequency (f) can be used to accurately determine the reactive current i_c, as explained above.

[0077] In addition, Figure 4 In a specific embodiment, the AC main input voltage and frequency (f) are determined using a single differential amplifier 408 (e.g., a high-impedance differential amplifier). In such an embodiment, obtaining the frequency (f) may only require one port of the ADC in the digital controller 418, compared to conventional control methods that measure the AC line voltage and AC neutral voltage and require two or more ADC ports.

[0078] In some implementations, control circuitry 406 can determine the input power supplied to SMPS 400. For example, digital controller 418 can determine the input power Pin of SMPS 400 based on an analog signal and the AC input current. More specifically, digital controller 418 can calculate the input power Pin by multiplying the RMS value of the AC main input voltage Vac calculated by equation (10) above with the RMS value of the AC input current i_in calculated by equation (1) above. In such embodiments, the power factor is assumed to be a value close to unit (1), such as 0.99.

[0079] The calculated input power pin can be used to calibrate the SMPS 400 based on the actual input power. For example, Figure 7 Graph 700 illustrates multiple values ​​PM1-4 of the calculated input power Pin under different loads and multiple values ​​P1-4 of the actual input power. Specifically, values ​​PM1 and P1 correspond to 10% load, values ​​PM2 and P2 correspond to 20% load, values ​​PM3 and P3 correspond to 50% load (half load), and values ​​PM4 and P4 correspond to 100% load (full load).

[0080] Based on the intersection of each corresponding calculated value and actual value, the offset error and gain error of the ADC in the digital controller 418 can be determined under various loads. For example, the offset error and gain error can be calculated based on values ​​PM1-4 and P1-4 corresponding to 10% load, 20% load, 50% load, and 100% load. For example, equations (11) and (12) below can be used to determine the offset error and gain error between 10% load and 20% load, respectively.

[0081]

[0082]

[0083] Furthermore, equations (13) and (14) below can be used to determine the offset error and gain error between 50% load and 100% load, respectively.

[0084]

[0085]

[0086] Offset error calculation and gain error calculation can also be applied to the output power of the SMPS 400. For example, the calculated output power of the SMPS 400 can be used to calibrate the SMPS 400 based on the actual output power. In such an embodiment, equations similar to those in equations (11)-(14) can be used to determine the offset error and gain error under various loads.

[0087] In some embodiments, the control circuitry disclosed herein can report one or more electrical parameters to an external device. For example... Figure 8 An example is an AC-DC SMPS800 including control circuitry 806 with an interface for communicating with external devices. In Figure 8 In a specific embodiment, the interface includes a power management bus (PMBus). In other embodiments, the interface may additionally and / or alternatively include an I-squared-C bus, a universal serial bus (USB), wires, connectors, terminals, etc.

[0088] like Figure 8 As shown, the SMPS 800 includes Figure 4 The filter 402, bridge rectifier 422, PFC circuit 404, and DC / DC power converter 420 are included. For example, the DC / DC power converter 420 may include at least one power switch 802 and a transformer 804 coupled to the power switch 802. Although the power switch 802 is shown along the high DC rail and coupled to the primary winding of the transformer 804, it will be apparent to those skilled in the art that the power switch 802 and / or transformer 804 may be coupled in another suitable manner, depending on, for example, the topology of the DC / DC power converter 420.

[0089] Figure 8 Control circuit 806 and Figure 4 The control circuit 406 is similar, but includes additional components for controlling the power switch 802 of the DC / DC power converter 420 and the power switch Q of the PFC circuit 404. For example, the control circuit 806 includes a main voltage regulation circuit 808, Figure 4 The system includes a digital controller 418 (e.g., a primary-side digital controller), a secondary-side digital controller 812, and an opto-coupler 810 coupled between the primary-side digital controller 418 and the secondary-side digital controller 812. The main voltage regulation circuit 808 may include a differential amplifier (e.g., Figure 4 Differential amplifier 408), comparator (e.g., Figure 4The comparator 412, etc., is used to generate signals based on the line voltage, neutral voltage, and power line frequency, as explained above. Furthermore, the digital controller 418 can determine the power line frequency, the reactive current in the filter 402, the AC input current Iin of the SMPS800, the AC main voltage Vac, the input power Pin, etc., as explained above.

[0090] The digital controller 812 controls one or more power switches in the DC / DC power converter 420. For example, the digital controller 812 receives signals representing the output voltage Vout and output current Iout of the DC / DC power converter 420, and then generates one or more control signals based on the received signals for controlling the power switches in the DC / DC power converter 420.

[0091] Furthermore, if desired, the digital controller 812 can calculate the output power Pout of the SMPS 800. In some embodiments, and as... Figure 8 As shown, control circuitry 806 can transmit the calculated output power Pout from secondary-side digital controller 812 to primary-side digital controller 418. In such an embodiment, primary-side digital controller 418 can use the output power Pout to estimate input power Pin (as explained further below), control power switches Q in PFC circuitry, etc. In other embodiments, secondary-side digital controller 812 can estimate input power Pin if desired.

[0092] Optocoupler 810 provides isolation between the primary-side and secondary-side control components in control circuitry 806. As shown, signals representing input parameters (e.g., AC mains voltage Vac, AC input current Iin, input power Pin, etc.) can be transmitted from the primary-side controller 418 to the secondary-side digital controller 812 via optocoupler 810, and signals representing output parameters (output power Pout, etc.) can be transmitted from the secondary-side controller 812 to the primary-side digital controller 418 via optocoupler 810. In some embodiments, input and output parameters can be transmitted via a Universal Asynchronous Receiver / Transmitter (UART) through optocoupler 810.

[0093] It can report one or more of the input and output parameters to external devices via a communication interface. For example, in Figure 8In a specific embodiment, one or more of the following parameters—AC main voltage Vac, AC input current Iin, input power Pin, output voltage Vout, output current Iout, output power Pout, etc.—can be transmitted to an external device via the secondary-side digital controller 812 through the PMBus. This allows the user to check and confirm that the input and output parameters of the SMPS 800 are at the expected levels and to verify the accuracy of the calculated values ​​of the parameters. In other embodiments, the primary-side digital controller 418 can report any one or more of the input and output parameters to an external device via a communication interface.

[0094] In other implementations, it may be desirable to report the calculated values ​​of one or more electrical parameters based on the accuracy of the calculated values. For example, Figure 9 A method 900 for reporting the AC input electrical parameters of an SMPS including filters and PFC circuitry is illustrated. For example... Figure 9 As shown, method 900 includes calculating the values ​​of the AC input electrical parameters of the SMPS in block 902. For example, and as further explained below, the AC input electrical parameters can be determined based on, for example, the reactive current in a filter, the PFC input current, etc.

[0095] Method 900 also includes, in block 904, estimating the values ​​of the AC input electrical parameters of the SMPS. The estimated values ​​of the AC input electrical parameters can be determined based on known characteristics of the SMPS, such as efficiency and output power.

[0096] Furthermore, method 900 includes determining the average value of the calculated AC input electrical parameters in block 906. For example, the AC input electrical parameters can be averaged over a number of samples across multiple AC cycles. Averaging the calculated AC input electrical parameters can increase the accuracy of the electrical parameters. In some embodiments, this step is performed if the difference between the calculated value and the estimated value of the AC input electrical parameters is less than a defined tolerance threshold.

[0097] Method 900 also includes determining the accuracy of the calculated value of the AC input electrical parameter in block 908, and reporting the calculated value of the input electrical parameter to an external device in block 910. The accuracy of the calculated AC input electrical parameter may be based on, for example, the average value of the AC input electrical parameter. Furthermore, in some embodiments, if the accuracy of the calculated value of the AC input electrical parameter is less than a defined accuracy threshold, the calculated value of the input electrical parameter is reported.

[0098] Figure 9 The AC input electrical parameters can be any suitable electrical parameters of the SMPS, such as the AC input current and input power of the SMPS. For example, Figure 10A method 1000 for calibrating (or recalibrating) and reporting the input power of SMPS is illustrated.

[0099] like Figure 10 As shown, method 1000 includes calculating the AC input power Pin.cal of the SMPS in block 1002 and calculating the DC output power Pout.cal of the SMPS in block 1004. For example, the AC input power Pin.cal can be determined based on the calculated AC input current (e.g., the RMS value of the AC input current) and the AC input voltage (e.g., the RMS value of the AC input voltage), as explained above with respect to equations (1) and (10). In such an embodiment, the calculated AC input current can be based on the reactive current in the filter, the PFC current, the power line frequency, etc., as explained above. The DC output power Pout.cal can be determined based on the sensed output voltage Vout and output current Iout of the DC / DC power converter, as explained above with respect to equations (1) and (10). Figure 8 The explanation given.

[0100] Next, method 1000 includes a lookup table in block 1006 and an estimated AC input power Pin.est in block 1008. For example, the table may include various known efficiency curves based on actual measurements. The table may be a lookup table stored, for example, in a control circuit implementing method 1000. The estimated AC input power Pin.est may be calculated based on the calculated output power Pout.cal (which is generally more accurate than the calculated input power Pin.cal) and the efficiency curves. For example, the estimated AC input power Pin.est may be calculated based on equation (15) below. In equation (15), η represents the efficiency of the SMPS under the calculated output power Pout.cal. PFC η represents the efficiency of the PFC circuit. DC / DC This indicates the efficiency of the DC / DC power converter, etc.

[0101]

[0102] Method 1000 also includes determining in block 1010 whether the difference ΔPin between the calculated AC input power Pin.cal and the estimated AC input power Pin.est is less than a defined tolerance threshold ε. The defined tolerance threshold ε can be any suitable value that depends on, for example, the desired accuracy of the estimated AC input power Pin.est and the AC input power Pin.cal. For example, if the desired accuracy is within a certain value, the defined tolerance threshold ε can be equal to the estimated AC input power Pin.est multiplied by that specific value. For example, if the estimated AC input power Pin.est is 869W and the desired accuracy is within 2%, the defined tolerance threshold ε can be equal to approximately 17W (869W * 2%).

[0103] In block 1010, if it is determined that the difference ΔPin between the calculated AC input power Pin.cal and the estimated AC input power Pin.est is greater than or equal to a defined tolerance threshold ε, method 1000 returns to block 1002 to calculate the AC input power Pin.cal of the SMPS. In such an embodiment, the AC input power Pin.cal can be recalculated to attempt to determine a more accurate value. For example, any of the various parameters used in calculating the AC input power Pin.cal can be changed. For example, parameters such as reactive current, AC input current, power line frequency, etc., can be recalculated to determine a more accurate value. Thus, the AC input current can be determined, and the AC input power Pin.cal can become more accurate. In this way, the AC input power Pin.cal can be calibrated (or recalibrated) to obtain a more accurate value.

[0104] In block 1010, if it is determined that the difference ΔPin between the calculated AC input power Pin.cal and the estimated AC input power Pin.est is less than a defined tolerance threshold ε, the average value of the AC input power Pin.avg is calculated in block 1012. In some embodiments, averaging the value of the AC input power Pin.cal can improve accuracy. For example, the average value of the AC input power Pin.avg can be calculated based on equation (16) below. In equation (16), N can represent any suitable value, including, for example, the number of samples within multiple AC cycles. In some embodiments, it is desirable to increase the value of N to achieve a more accurate average value of the AC input power Pin.cal.

[0105]

[0106] Next, method 1000 includes determining in block 1014 whether the accuracy of the calculated AC input power Pin.cal is less than a defined accuracy threshold Acc_threshold. This determination can be based on the average AC input power Pin.avg, as shown in equation (17-1) below.

[0107]

[0108] The defined accuracy threshold, Acc_threshold, can be based on any suitable value, such as design parameters. In some embodiments, the defined accuracy threshold, Acc_threshold, can depend on the load coupled to the SMPS. For example, for loads ranging from 20% to 100% load, the defined accuracy threshold, Acc_threshold, could be 2%. In other embodiments, for lighter loads (e.g., loads ranging from 10% to 20% load), the defined accuracy threshold, Acc_threshold, could be 5%.

[0109] If, in block 1014, it is determined that the accuracy of the calculated AC input power Pin.cal is greater than or equal to a defined accuracy threshold, method 1000 returns to block 1002 to calculate (or recalculate) the AC input power Pin.cal of the SMPS in an attempt to determine a more accurate value for the AC input power Pin.cal, as explained above. In such an embodiment, the AC input power Pin.cal can be calibrated (or recalibrated) to obtain a more accurate value. However, if, in block 1014, the accuracy of the calculated AC input power Pin.cal is determined to be less than a defined accuracy threshold, the calculated AC input power Pin.cal can be reported to an external device in block 1016. For example, the calculated AC input power Pin.cal can be reported via PMBus, as explained above.

[0110] In other embodiments, Figure 9 The AC input electrical parameter can be the AC input current. For example, Figure 11 A method 1100 for calibrating (or recalibrating) and reporting the AC input current of SMPS is illustrated. Figure 11 Method 1100 and Figure 10 The method is largely similar to 1000, but it refers to the AC input current.

[0111] For example, and as Figure 11As shown, method 1100 includes calculating the AC input current Iin.cal of the SMPS in block 1102 and calculating the DC output power Pout.cal of the SMPS in block 1104. The AC input current Iin.cal can be determined based on reactive current, PFC current, power line frequency, etc., as explained above.

[0112] Method 1100 then includes a lookup table in block 1106 and an estimated AC input current Iin.est in block 1108. As explained above, this table (e.g., a stored lookup table) may include various known efficiency curves based on actual measurements. Figure 11 The estimated AC input current Iin.est can be calculated based on the calculated output power Pout.cal, the efficiency curve, and the AC main voltage Vac. For example, the estimated AC input current Iin.est can be calculated based on equation (17-2) below.

[0113]

[0114] Next, method 1100 includes determining in block 1110 whether the difference ΔIin between the calculated AC input current Iin.cal and the estimated AC input current Iin.est is less than a defined tolerance threshold ε. For example, the defined tolerance threshold ε can be determined in a similar manner to that explained above regarding the tolerance threshold ε for input power.

[0115] If, in block 1110, it is determined that the difference ΔIin between the calculated AC input current Iin.cal and the estimated AC input current Iin.est is greater than or equal to a defined tolerance threshold ε, method 1100 returns to the calculation (or recalculation) of the AC input current Iin.cal in block 1102 to attempt to determine a more accurate value for the AC input current Iin.cal. In such an embodiment, if more accurate values ​​for reactive current, PFC current, power line frequency, etc., are obtained, the AC input current Iin.cal can be calibrated (or recalibrated) and / or determined to obtain a more accurate value. However, if, in block 1110, it is determined that the difference ΔIin between the calculated AC input current Iin.cal and the estimated AC input current Iin.est is less than a defined tolerance threshold ε, the average value Iin.avg of the AC input current is calculated in block 1112. This can improve the accuracy of the AC input current Iin.cal. For example, the average value Iin.avg of the AC input current can be calculated based on equation (17-3) below. In equation (17-3), N can represent the number of samples within multiple AC cycles, as explained above.

[0116]

[0117] Method 1100 also includes determining in block 1114 whether the accuracy of the calculated AC input current Iin.cal is less than a defined accuracy threshold Acc_threshold. The defined accuracy threshold Acc_threshold related to the calculated AC input current Iin.cal can be any suitable value, such as 2%, 5%, etc., as explained above regarding defined accuracy thresholds related to AC input power. The accuracy of the calculated AC input current Iin.cal is determined based on the average AC input power Iin.avg, as shown in equation (18) below.

[0118]

[0119] In block 1114, if the accuracy of the calculated AC input current Iin.cal is greater than or equal to a defined accuracy threshold, method 1100 returns to block 1102 to calculate (or recalculate) the AC input current Iin.cal in an attempt to determine a more accurate value for the AC input current Iin.cal (e.g., recalibrate), as explained above. However, if the accuracy of the calculated AC input current Iin.cal determined in block 1114 is less than the defined accuracy threshold, in block 1116 the calculated AC input power Iin.cal can be reported to an external device via, for example, a PMBus, as explained above.

[0120] Methods 900, 1000, and 1100 for calibrating (or recalibrating) and / or reporting AC input electrical parameters can be implemented by any suitable control circuit, including, for example, any of the control circuits disclosed herein. In some embodiments, some or all portions of the methods can be implemented using one or more of the digital controllers disclosed herein (e.g., primary-side digital controllers, secondary-side digital controllers, etc.). Furthermore, methods for calibrating (or recalibrating) and / or reporting AC input electrical parameters can be implemented in the control circuit in conjunction with methods for determining AC input current. In other embodiments, methods for recalibrating and / or reporting AC input electrical parameters (and not methods for determining AC input current) or vice versa can be implemented in the control circuit.

[0121] The control circuits disclosed herein may include analog control circuits, digital control circuits, or hybrid control circuits (e.g., digital control units and analog circuits). Digital control circuits can be implemented using one or more types of digital control circuit systems. For example, each digital control circuit may include a digital controller, such as a digital signal controller (DSC), a DSP, a microcontroller unit (MCU), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), etc. Thus, any of the control methods disclosed herein can be executed at least partially (and sometimes entirely) by a digital controller.

[0122] For example, if the control circuit is a digital control circuit, it can be implemented using one or more hardware components and / or software. For instance, instructions for performing any one or more of the features disclosed herein can be stored and / or transferred from a non-transient computer-readable medium, etc., to one or more existing digital control circuits, new digital control circuits, etc. In such embodiments, one or more of the instructions can be stored in volatile memory, non-volatile memory, ROM, RAM, one or more hard disks, disk drives, optical disk drives, removable memory, non-removable memory, magnetic tape cartridges, flash memory cards, CD-ROMs, DVDs, cloud storage, etc.

[0123] For example, if the corresponding power circuit includes an isolation transformer, the control circuit portion can be located on the secondary side of the isolation barrier. In such a case, control signals from the control circuit can cross the isolation barrier (e.g., via one or more isolation devices, such as an isolation transformer, optocoupler, etc.) to control the power switch on the primary side of the power circuit, such as... Figure 8 As shown in the figure.

[0124] Furthermore, the control methods disclosed herein can be repeated as desired. For example, the control circuit can be able to continuously execute the methods as desired and / or, if applicable.

[0125] The teachings disclosed herein can be applied to any suitable SMPS having one or more power circuits. In some embodiments, the teachings can be implemented in at least a portion of a front-end AC-DC distributed power supply. In such embodiments, the power supply can receive an AC input voltage in the range of 90-264VAC at a power line frequency in the range of 47-63Hz and provide a regulated 12VDC output or another suitable output voltage. For example, the power supply can have a rated output power of 800W at 12V / 66.7A, a rated output power of 1800W at 12V / 147.5A, a rated output power of 2000W at 12V / 163.9A, a rated output power of 2400W at 12V / 196.7A, and / or another suitable rated power. In some embodiments, the power supply can include a redundant architecture and provide a single output. The power supply can be particularly useful in server applications, storage applications (e.g., database applications, cloud hosting applications, etc.), network applications, etc.

[0126] By employing the control method disclosed herein, an AC main voltage can be generated to include accurate zero crossings without delay, a delay typically seen in conventional methods when sampling line and neutral voltages. Therefore, an accurate value of the power line frequency can be obtained from the zero crossings, and accurate input current determination can be achieved based on the power line frequency. In some embodiments, the AC main voltage can be generated using a single differential amplifier. In such embodiments, only a portion of the ADC in the digital controller (if employed) may be required, compared to multiple ports in conventional methods.

[0127] Furthermore, the control method described herein can provide a solution for measuring input power without relying on power metering devices (e.g., power meter chips) as in conventional methods. Therefore, it reduces costs and increases board space compared to conventional methods. Thus, the teachings disclosed herein can provide a low-cost, compact SMPS design.

[0128] Furthermore, the control method can provide a solution for calibrating (or recalibrating) input parameters such as AC input current and input power to improve parameter accuracy. If the parameter accuracy is sufficient, it can be reported to an external device if desired. Calibration (or recalibration) of the input parameters can be performed while the SMPS is running (e.g., online). In this way, calibration can be based on real-time calculations.

[0129] The following implementation plans, numbered as follows, were also disclosed:

[0130] 1. A switch-mode power supply (SMPS), comprising:

[0131] Linear rails and neutral rails;

[0132] A filter coupled between the linear rail and the neutral rail, the filter including an input, an X capacitor, and an output for receiving AC input voltage and AC input current;

[0133] A power factor correction (PFC) circuit, coupled to the output of the filter, the PFC circuit including an input for receiving a PFC AC current; and

[0134] A control circuit coupled to the PFC circuit is configured to: generate an analog signal representing the difference between the AC line voltage and the AC neutral voltage; compare the analog signal with the defined threshold to determine the zero crossing of the analog signal; determine the frequency of the AC input voltage or the AC input current based on at least two of the zero crossings of the analog signal; determine the reactive current flowing through the X capacitor in the filter based on the determined frequency; and determine the AC input current of the SMPS based on the determined reactive current and the PFC AC current.

[0135] 2. The SMPS according to any of the foregoing embodiments, wherein the control circuitry includes a differential amplifier configured to generate the analog signal.

[0136] 3. The SMPS according to any of the foregoing embodiments, wherein the control circuitry includes a digital controller configured to receive the analog signal and determine the input power of the SMPS based on the analog signal and the AC input current.

[0137] 4. The SMPS according to any of the foregoing embodiments, wherein the control circuitry includes a comparator configured to compare the analog signal with the defined threshold, and generate a square wave signal having a rising edge and a falling edge based on the comparison between the analog signal and the defined threshold, wherein the rising edge or the falling edge corresponds to the zero crossing.

[0138] 5. The SMPS according to any of the foregoing embodiments, wherein the control circuit is configured to: determine the input power of the SMPS, determine the accuracy of the input power based on the average value of the input power, and report the input power to an external device if the accuracy is less than a defined accuracy threshold.

[0139] 6. The SMPS according to any of the foregoing embodiments, wherein the determined value of the input power is a first determined value of the input power, and wherein the control circuit is configured to determine another value of the input power if the accuracy of the first determined value of the input power is greater than or equal to the defined accuracy threshold.

[0140] 7. The SMPS according to any of the foregoing embodiments, wherein the control circuit is configured to determine the accuracy of the determined AC input current based on the average value of the AC input current, and to report the determined AC input current to an external device if the accuracy is less than a defined accuracy threshold.

[0141] 8. The SMPS according to any of the foregoing embodiments, wherein the determined value of the AC input current is a first determined value of the AC input current, and wherein the control circuit is configured to determine another value of the AC input current if the accuracy of the first determined value of the AC input current is greater than or equal to the defined accuracy threshold.

[0142] 9. An SMPS comprising:

[0143] A filter comprising an input, an X capacitor, and an output for receiving AC input current.

[0144] A PFC circuit, the PFC circuit being coupled to the output of the filter; and

[0145] A control circuit coupled to the PFC circuit is configured to: determine the value of the AC input electrical parameter of the SMPS; estimate the value of the AC input electrical parameter of the SMPS based on a defined efficiency and output power of the SMPS; determine an average value of the AC input electrical parameter if the difference between the determined value and the estimated value of the AC input electrical parameter is less than a defined tolerance threshold; determine the accuracy of the determined value of the AC input electrical parameter based on the average value of the AC input electrical parameter; and report the determined value of the AC input electrical parameter to an external device if the accuracy of the determined value of the AC input electrical parameter is less than a defined accuracy threshold.

[0146] 10. The SMPS according to any of the foregoing embodiments, wherein the AC input electrical parameter is the AC input current or AC input power of the SMPS.

[0147] 11. The SMPS according to any of the foregoing embodiments, wherein the control circuit is configured to: determine the reactive current in the filter and the PFC current supplied to the PFC circuit; and determine the value of the AC input electrical parameter based on the reactive current and the PFC current.

[0148] 12. The SMPS according to any of the foregoing embodiments, wherein the control circuit is configured to: determine the frequency of the AC input current; and determine the reactive current based on the frequency of the AC input current.

[0149] 13. The SMPS according to any of the foregoing embodiments, wherein the control circuit is configured to determine the frequency of the AC input current by: generating an analog signal representing the difference between the AC line voltage in the SMPS and the AC neutral voltage in the SMPS, comparing the analog signal with a defined threshold to determine the zero crossing of the analog signal, and determining the frequency of the AC input current of the SMPS based on the zero crossing of the analog signal.

[0150] 14. The SMPS according to any of the foregoing embodiments, wherein the determined value of the AC input electrical parameter is a first determined value of the AC input electrical parameter, and wherein the control circuit is configured to determine another value of the AC input electrical parameter if the difference between the first determined value of the AC input electrical parameter and the estimated value of the AC input electrical parameter is greater than or equal to a defined tolerance threshold.

[0151] 15. The SMPS according to any of the foregoing embodiments, wherein the determined value of the AC input electrical parameter is a first determined value of the AC input electrical parameter, and wherein the control circuit is configured to determine another value of the AC input electrical parameter if the accuracy of the first determined value of the AC input electrical parameter is greater than or equal to the defined accuracy threshold.

[0152] 16. An SMPS comprising:

[0153] Linear rails and neutral rails;

[0154] A filter coupled between the linear rail and the neutral rail, the filter including an input for receiving AC input voltage and AC input current;

[0155] A PFC circuit, the PFC circuit being coupled to the output of the filter; and

[0156] A control circuit including a differential amplifier and a digital controller, the differential amplifier being configured to generate an analog signal representing the difference between an AC line voltage and an AC neutral voltage, and the digital controller being configured to determine, based on the analog signal, the frequency of the AC input voltage and the frequency of the AC input current.

[0157] 17. The SMPS according to any of the foregoing embodiments, wherein the control circuitry includes a comparator coupled between the differential amplifier and the digital controller, wherein the comparator is configured to compare the analog signal with a defined threshold to determine zero crossings of the analog signal, and wherein the digital controller is configured to determine the frequency of the AC input voltage or the AC input current based on at least two of the zero crossings of the analog signal.

[0158] 18. The SMPS according to any of the foregoing embodiments, wherein the comparator is configured to generate a square wave signal having a rising edge and a falling edge based on a comparison between the analog signal and the defined threshold, and wherein the rising edge or the falling edge corresponds to the zero crossing.

[0159] 19. The SMPS according to any of the foregoing embodiments, wherein at least two of the zero crossings of the analog signal are two consecutive zero crossings of the analog signal.

[0160] 20. The SMPS according to any of the foregoing embodiments, wherein the filter includes an X capacitor, and wherein the digital controller is configured to determine the reactive current flowing through the X capacitor based on a determined frequency.

[0161] 21. The SMPS according to any of the foregoing embodiments, wherein the PFC circuit includes an input for receiving a PFC AC current, and wherein the digital controller is configured to determine the AC input current based on a determined reactive current and the PFC AC current.

[0162] 22. The SMPS according to any of the foregoing embodiments, wherein the digital controller is configured to: determine the accuracy of the determined AC input current based on the average value of the AC input current; and report the determined AC input current to an external device if the accuracy is less than a defined accuracy threshold.

[0163] 23. The SMPS according to any of the foregoing embodiments, wherein the determined value of the AC input current is a first determined value of the AC input current, and wherein the control circuit is configured to determine another value of the AC input current if the accuracy of the first determined value of the AC input current is greater than or equal to the defined accuracy threshold.

[0164] 24. The SMPS according to any of the foregoing embodiments, wherein the digital controller is configured to receive the analog signal and determine the input power of the SMPS based on the determined AC input voltage signal and the determined AC input current.

[0165] 25. The SMPS according to any of the foregoing embodiments, wherein the digital controller is configured to: determine the accuracy of the input power based on the average value of the input power, and report the input power to an external device if the accuracy is less than a defined accuracy threshold.

[0166] 26. The SMPS according to any of the foregoing embodiments, wherein the determined value of the input power is a first determined value of the input power, and wherein the control circuit is configured to determine another value of the input power if the accuracy of the first determined value of the input power is greater than or equal to the defined accuracy threshold.

[0167] 27. An SMPS comprising:

[0168] Linear rails and neutral rails;

[0169] A filter coupled between the linear rail and the neutral rail, the filter including an input, an X capacitor, and an output for receiving AC input voltage and AC input current;

[0170] A PFC circuit coupled to the output of the filter, the PFC circuit including an input for receiving PFC AC current, at least one power switch, and an output;

[0171] A DC / DC power circuit, said DC / DC power circuit being coupled to the output of the PFC circuit, said DC / DC power circuit including at least one power switch and a transformer; and

[0172] A control circuit coupled to the PFC circuit for controlling at least one power switch of the PFC circuit, and coupled to the DC / DC power circuit for controlling at least one power switch of the DC / DC power circuit, the control circuit including at least one differential amplifier, a primary-side digital controller, a secondary-side digital controller, and an isolation device coupled between the primary-side digital controller and the secondary-side digital controller, the differential amplifier being configured to generate an analog signal representing the difference between the AC line voltage and the AC neutral voltage, and the primary-side digital controller being configured to: determine the AC input voltage based on the analog signal, determine the frequency of the AC input voltage or the AC input current based on the analog signal, determine the reactive current flowing through the X capacitor based on the determined frequency, and determine the AC input current based on the determined reactive current and the PFC AC current.

[0173] 28. The SMPS according to any of the foregoing embodiments, wherein the control circuitry includes a comparator coupled between the differential amplifier and the primary-side digital controller, wherein the comparator is configured to compare the analog signal with a defined threshold to determine a zero-crossing of the analog signal, and wherein the primary-side digital controller is configured to determine the frequency of the AC input voltage or the AC input current based on at least two of the zero-crossings of the analog signal.

[0174] 29. The SMPS according to any of the foregoing embodiments, wherein the comparator is configured to generate a square wave signal having a rising edge and a falling edge based on a comparison between the analog signal and the defined threshold, and wherein the rising edge or the falling edge corresponds to the zero crossing.

[0175] 30. The SMPS according to any of the foregoing embodiments, wherein at least two of the zero crossings of the analog signal are two consecutive zero crossings of the analog signal.

[0176] 31. The SMPS according to any of the foregoing embodiments, wherein the primary-side digital controller is configured to determine the AC input current based on the determined reactive current and the PFC AC current.

[0177] 32. The SMPS according to any of the foregoing embodiments, wherein the primary-side digital controller is configured to determine the accuracy of the determined AC input current based on the average value of the AC input current, and wherein the secondary-side digital controller is configured to report the determined AC input current to an external device if the accuracy is less than a defined accuracy threshold.

[0178] 33. The SMPS according to any of the foregoing embodiments, wherein the determined value of the AC input current is a first determined value of the AC input current, and wherein the primary-side digital controller is configured to determine another value of the AC input current if the accuracy of the first determined value of the AC input current is greater than or equal to the defined accuracy threshold.

[0179] 34. The SMPS according to any of the foregoing embodiments, wherein the primary-side digital controller is configured to receive the analog signal and determine the input power of the SMPS based on the determined AC input voltage signal and the determined AC input current.

[0180] 35. The SMPS according to any of the foregoing embodiments, wherein the primary-side digital controller is configured to determine the input power of the SMPS and to determine the accuracy of the input power based on an average value of the input power, and wherein the secondary-side digital controller is configured to report the input power to an external device if the accuracy is less than a defined accuracy threshold.

[0181] 36. The SMPS according to any of the foregoing embodiments, wherein the determined value of the input power is a first determined value of the input power, and wherein the primary-side digital controller is configured to determine another value of the input power if the accuracy of the first determined value of the input power is greater than or equal to the defined accuracy threshold.

[0182] The foregoing description of embodiments has been provided for illustrative and descriptive purposes. It is not intended to be exhaustive or limiting of this disclosure. Elements or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable where applicable and can be used in a chosen embodiment, even if not specifically shown or described. Variations are also possible in various ways. Such variations should not be considered as departing from this disclosure, and all such modifications are intended to be included within the scope of this disclosure.

Claims

1. A switch-mode power supply, i.e., SMPS, comprising: Linear rails and neutral rails; A filter coupled between the linear rail and the neutral rail, the filter including an input, an X capacitor, and an output for receiving AC input voltage and AC input current; A power factor correction circuit, i.e., a PFC circuit, coupled to the output of the filter, the PFC circuit including an input for receiving PFC AC current; as well as A control circuit, coupled to the PFC circuit, is configured to: Generate an analog signal representing the difference between the AC line voltage and the AC neutral voltage. The analog signal is compared with a defined threshold to determine the zero-crossing of the analog signal. The frequency of the AC input voltage or the AC input current is determined based on at least two of the zero crossings of the analog signal. The reactive current flowing through the X capacitor in the filter is determined based on the determined frequency. The calculated AC input current of the SMPS is determined based on the determined reactive current and the PFC AC current. Based on the defined efficiency, output power, and AC main voltage of the SMPS, the estimated AC input current of the SMPS is determined. Determine the difference between the calculated AC input current and the estimated AC input current. When the difference is less than a defined tolerance threshold, the average value of the AC input current is determined. Based on the average value of the AC input current, the accuracy of the calculated AC input current is determined, and If the accuracy is less than a defined accuracy threshold, the calculated AC input current is reported to an external device.

2. The switch-mode power supply of claim 1, wherein the control circuitry includes a differential amplifier configured to generate the analog signal.

3. The switch-mode power supply of claim 1, wherein the control circuitry includes a digital controller configured to receive the analog signal and determine the input power of the SMPS based on the analog signal and the AC input current.

4. The switch-mode power supply according to any one of claims 1-3, wherein the control circuit includes a comparator configured to compare the analog signal and the defined threshold, and generate a square wave signal having a rising edge and a falling edge based on the comparison between the analog signal and the defined threshold, wherein the rising edge or the falling edge corresponds to the zero crossing.

5. An SMPS comprising: A filter, the filter comprising an input for receiving AC input current, an X capacitor, and an output; A PFC circuit is coupled to the output of the filter; as well as A control circuit coupled to the PFC circuit, the control circuit being configured to: determine the value of the AC input electrical parameters of the SMPS; The values ​​of the AC input electrical parameters of the SMPS are estimated based on the defined efficiency and output power of the SMPS; if the difference between the determined value of the AC input electrical parameters and the estimated value of the AC input electrical parameters is less than a defined tolerance threshold, the average value of the AC input electrical parameters is determined; the accuracy of the determined value of the AC input electrical parameters is determined based on the average value of the AC input electrical parameters; and if the accuracy of the determined value of the AC input electrical parameters is less than a defined accuracy threshold, the determined value of the AC input electrical parameters is reported to an external device.

6. The SMPS according to claim 5, wherein the AC input electrical parameter is the AC input current or AC input power of the SMPS.

7. The SMPS of claim 5, wherein the control circuit is configured to: determine the reactive current in the filter and the PFC current supplied to the PFC circuit, and determine the value of the AC input electrical parameter based on the reactive current and the PFC current.

8. The SMPS according to any one of claims 5-7, wherein the determined value of the AC input electrical parameter is a first determined value, and wherein the control circuit is configured to: determine another value of the AC input electrical parameter if the difference between the first determined value and the estimated value of the AC input electrical parameter is greater than or equal to the defined tolerance threshold, or if the accuracy of the first determined value is greater than or equal to the defined accuracy threshold.

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