PFC switching power supply and operation method thereof, and PFC controller used for PFC switching power supply

Abstract

The invention discloses a PFC (Power Factor Correction) controller for a PFC switching power supply, a method for operating the PFC switching power supply and the PFC switching power supply. The PFC controller includes a peak controller configured to receive a feedback signal indicative of an input power provided to a downstream power converter. The peak current controller is configured to generate a first reference current signal, and the first multiplier generates a product signal by multiplying a reference symbol with the first reference current signal. The second multiplier generates a second reference current based on the product signal and the voltage error signal. The current regulator generates a current regulation signal using the second reference current and the line current. The modulator is configured to regulate the output power generated by the PFC switching power supply using the current regulation signal.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to power factor correction (PFC) switching power supplies, and in particular to a PFC controller for a PFC switching power supply, a method for operating a PFC switching power supply, and a PFC switching power supply. BACKGROUND

[0002] PFC switching power supplies are used to convert AC input power to DC output power that can be used by a load circuit, such as a downstream power supply (e.g., a buck converter). A PFC switching power supply can operate such that the output power is provided at a desired power factor (a ratio between apparent power and real power absorbed by the load circuit). A PFC switching power supply can operate in different modes depending on the conditions of the load circuit. These modes can include continuous current mode, discontinuous current mode, and critical current mode. SUMMARY

[0003] A PFC controller for a PFC switching power supply is disclosed. In one embodiment, a PFC controller for a power factor correction (PFC) switching power supply includes a peak current controller configured to receive a feedback signal indicative of an input power of a downstream power converter on a feedback terminal, where the peak current controller is further configured to generate a first reference current signal using the feedback signal. The PFC controller further includes a first multiplier configured to generate a product signal based on a product of a reference sinusoidal wave signal and the first reference current signal, where the reference sinusoidal wave signal is based on an AC input signal received by the PFC switching power supply; and a second multiplier configured to create a second reference current signal based on the product signal and a voltage error signal. A current regulator is configured to generate a current regulation signal using the second reference current signal and a line current of the PFC switching power supply. A modulator is configured to regulate an output power generated by the PFC switching power supply, where to regulate the output power, the modulator is configured to control an assertion time of a signal applied to a drive terminal.

[0004] In some embodiments, a control scheme used in each of a plurality of operating modes of the PFC controller is shared across the plurality of operating modes. The plurality of operating modes includes discontinuous current mode, critical current mode, and continuous current mode.

[0005] In various implementations, the modulator is configured to control the assertion time of the signal applied to the drive terminal using pulse width modulation (PWM), where the drive terminal is coupled to a control terminal of a switch of the PFC switching power supply.

[0006] In some implementations, the PFC controller further includes a reference signal generator configured to generate a reference sinusoidal wave signal using the input reference signal, where the reference signal generator is further configured to generate a voltage signal indicative of a root mean square (RMS) voltage of the AC input signal. To generate the first reference current signal, the peak current controller is configured to divide the feedback signal by the voltage signal.

[0007] In various embodiments, the PFC controller further includes an error amplifier configured to generate a voltage error signal based on a reference voltage and a DC sense voltage received from the PFC switching power supply. Embodiments of the PFC controller and / or the PFC switching power supply including an overcurrent protection unit are additionally possible and contemplated, where the modulator is configured to cause the line current to be limited in response to detection of an overcurrent condition by the overcurrent protection unit. The driver is implemented in some embodiments of the PFC controller, where the driver is configured to control activation of the switches of the PFC switching power supply based on a control signal received from the modulator.

[0008] A method for operating a power factor correction (PFC) switching power supply is disclosed, the method including regulating output power produced by the PFC switching power supply using a controller. In various implementations, the regulating includes generating a first reference current signal by a peak current controller and using a feedback signal indicative of an amount of power drawn by a downstream load. The regulating further includes multiplying a reference sinusoidal wave signal with the first reference current signal using a first multiplier to produce a product signal, where the reference sinusoidal wave signal is based on an AC input signal received by the PFC switching power supply; and multiplying the product signal with a voltage error signal using a second multiplier to generate a second reference current signal. The regulating further includes creating a current regulation signal by a current regulator using the second reference current signal and a line current in the PFC switching power supply; and controlling an assertion time of a signal applied to a drive terminal of the PFC switching power supply by a modulator and using the current regulation signal.

[0009] In some embodiments, the method can further include implementing a control scheme shared in each of a plurality of operating modes using the controller. The plurality of operating modes can include any or all (in various combinations) of a discontinuous current mode, a continuous current mode, and / or a critical current mode.

[0010] In various embodiments, the controlling an assertion time of a signal applied to a drive terminal of the PFC switching power supply includes the modulator using pulse width modulation (PWM).

[0011] The method can further include generating, using the reference signal generator, a reference sinusoidal signal, and wherein the method further includes generating, using the reference signal generator, a voltage signal indicative of a root mean square (RMS) voltage of the AC input signal. In some embodiments, the method can further include dividing, using the peak current controller, the feedback signal by the voltage signal to produce a first reference current signal.

[0012] Some embodiments of the method include generating, using the error amplifier, a reference voltage, and a DC sense voltage received from the PFC switching power supply, a voltage error signal.

[0013] The present disclosure also presents a power factor correction (PFC) switching power supply. The PFC switching power supply includes a filter configured to produce a filtered AC signal by filtering an AC input signal received by the PFC switching power supply; a rectifier configured to rectify the filtered AC signal to produce a rectified signal; an inductor coupled between the rectifier and a switching node; an electrically controlled switch having a first terminal coupled to the switching node, a second terminal coupled to a reference node, and a control terminal; and a controller having an input reference signal terminal, a feedback input terminal, and a control output terminal, wherein the controller is configured to regulate an output power produced by the PFC switching power supply. The controller includes a reference signal generator configured to produce a reference sinusoidal signal using an input reference signal received via the input reference signal terminal, and further configured to produce a voltage signal indicative of a root mean square (RMS) voltage of the AC input signal using the input reference signal; a peak current generator configured to receive a feedback signal indicative of the power produced by the PFC switching power supply on the feedback terminal, and further configured to generate a first reference current signal by dividing the feedback signal by the voltage signal; a first multiplier configured to generate a product signal based on a product of the reference sinusoidal signal and the first reference current signal; an error amplifier configured to output a voltage error signal based on a reference voltage and a DC sense voltage indicative of a DC output voltage generated by the PFC switching power supply; a second multiplier configured to create a second reference current signal based on the product signal and the voltage error signal; a current regulator configured to generate a current regulation signal using the second reference current signal and a line current from the PFC controller; a modulator configured to produce a modulation control signal based on the second reference current signal; and a driver coupled to the control terminal, wherein the driver is configured to control a conduction time of the switch based on the modulation control signal. The control scheme used in each of a plurality of operating modes of the PFC switching power supply is shared among the plurality of operating modes. In various embodiments, the plurality of operating modes includes a discontinuous current mode, a continuous current mode, and a critical current mode. BRIEF DESCRIPTION OF DRAWINGS

[0014] To describe the example embodiments in detail, reference will now be made to the accompanying drawings in which:

[0015] Figure 1 is a block diagram illustrating one embodiment of a PFC switching power supply;

[0016] Figure 2A and Figure 2B together illustrate another embodiment of a PFC switching power supply;

[0017] Figure 3 is a graph illustrating the operation of one embodiment of a PFC switching power supply;

[0018] Figure 4 is a graph illustrating the operation of one embodiment of a PFC switching power supply;

[0019] Figure 5 is a graph illustrating the operation of one embodiment of a PFC switching power supply;

[0020] Figure 6 is a flowchart illustrating a method for operating one embodiment of a PFC switching power supply; and

[0021] Figure 7 is a flowchart illustrating another method for operating one embodiment of a PFC switching power supply.

[0022] Definitions

[0023] Various terminology is used to refer to particular system components. Different companies may refer to a component by different names - this document does not intend to distinguish between components that differ in name but not in function. In the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to... Also, the term "couple" or "coupled" is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection can be through a direct connection, or through an indirect connection via other devices and connections.

[0024] As used herein, "a," "an," and "the" mean both singular and plural referents unless the context clearly dictates otherwise. For example, a "processor" programmed to perform various functions refers to one processor programmed to perform each function, or more than one processor collectively programmed to perform each of the various functions. For clarity, the initial mention of an item, followed by a subsequent reference to "the item" does not exclude the possibility that the item is more than one.

[0025] The terms "input" and "output" when used as nouns refer to connections (e.g., electrical connections, software connections) and should not be read as verbs requiring action. For example, a timer circuit can define a clock output. An example timer circuit can form or drive a clock signal on the clock output. In systems implemented directly in hardware (e.g., on a semiconductor substrate), these "inputs" and "outputs" define electrical connections. In systems implemented in software, these "inputs" and "outputs" define parameters read by or written to, respectively, by instructions implementing the functionality.

[0026] "Assert" shall mean to create or maintain a first predetermined state of a Boolean signal. The Boolean signal can be asserted to be a high level or to have a higher voltage, according to the judgment of the circuit designer, and the Boolean signal can be asserted to be a low level or to have a lower voltage. Similarly, "de-assert" shall mean to create or maintain a second predetermined state of the Boolean opposite from the asserted state.

[0027] "Controller" shall mean, individually or in combination, a separate circuit component, an application specific integrated circuit (ASIC), a microcontroller with control software, a reduced instruction set computer (RISC) with control software, a digital signal processor (DSP), a processor with control software, a programmable logic device (PLD), a field programmable gate array (FPGA), or a programmable system on a chip (PSOC), configured to read inputs and drive outputs in response to those inputs. DETAILED DESCRIPTION

[0028] The following discussion relates to various embodiments of the disclosed subject matter. While one or more embodiments can be preferred, the disclosed embodiments should not be construed as limiting the scope of the disclosure including the claims. Additionally, those skilled in the art will recognize that the description given herein has broad application and the discussion of any embodiment is meant only to illustrate the example nature of that embodiment and is not intended to represent the scope of the disclosure including the claims.

[0029] A PFC controller for controlling a PFC switching power supply can operate in different modes. One such mode is discontinuous current mode (DCM), in which the inductor current in the switching power supply falls to zero for at least a portion of a switching period. Another mode is continuous current mode (CCM), in which the inductor current does not fall to zero during a switching period. In another mode, critical current mode (CrM), the switching power converter operates near the boundary of CCM and DCM, in which a switch is activated when the inductor current reaches zero. These various modes of operation can depend on the input voltage and output power of the PFC switching power supply. The PFC controller for the PFC switching power supply utilizes different control schemes for the different modes, and can also utilize an output signal from the load circuit as a feedback signal. The use of different control schemes can complicate the transition between the different modes. In addition, the feedback signal provided to the PFC controller can be taken from the output of the load circuit in order to accurately reflect the power demand. The feedback signal taken from the output of the load circuit can introduce a delay in reflecting the output power provided by the PFC switching power supply, resulting in a phase lag that can slow the transient response time. Increasing compensation for the slow transient response time can introduce an overshoot.

[0030] A PFC controller that utilizes the output power of the PFC switching power supply as a feedback signal can operate without significant phase lag. The present disclosure also contemplates a PFC controller that uses a feedback signal as described above, enabling the use of a shared (same) control scheme for different modes of operation, such as DCM, CrM, and CCM modes.

[0031] Figure 1 is a block diagram illustrating one embodiment of a PFC switching power supply. In the illustrated embodiment, the PFC switching power supply 100 includes a PFC controller 101 and a PFC converter / switching unit 151. In various implementations, the PFC controller 101 can be implemented on an integrated circuit die (or dies), and packaged as a packaged semiconductor product. The PFC controller 101 as a packaged semiconductor product can then be combined with various circuit components of the PFC converter / switching unit 151 to create the entire PFC switching power supply.

[0032] The PFC converter / switching unit 151 is configured to convert AC input power to DC output power. Thus, the PFC converter / switching unit 151 includes circuitry for converting an AC signal to a DC signal, and can also include filters and other circuitry. Reference is made below to Figure 2A and Figure 2B One possible implementation of the circuitry for performing the functions of the PFC converter / switching unit 151 is discussed in additional detail.

[0033] As Figure 1The illustrated PFC controller 101 is configured to perform control functions for the PFC switching power supply 100 such that the output power from the PFC converter / switching unit 151 is provided within a desired specification. The PFC controller 101 is coupled to receive a feedback signal and a line current signal (indicative of line current) from the PFC converter / switching unit 151. A drive signal generated within the PFC controller 101 is used to control the operation of the PFC converter / switching unit 151, e.g., by controlling switches implemented in the latter. As illustrated herein, the PFC controller 101 includes a peak current controller 123, a multiplier 125, a multiplier 126, a current regulator 127, and a modulator 128. These components can implement a control scheme that is shared (remains the same) across different operating modes, such as those discussed above.

[0034] The peak current controller 123 in the illustrated embodiment is configured to generate a first reference current, reference current 1, using the feedback signal. The feedback signal provided to the peak current controller 123 is indicative of the output power provided by the PFC switching power supply 100 as input power to a load circuit, such as a downstream power converter. Although illustrated herein as being directly from the PFC converter / switching unit 151, it should be noted that in various implementations, the source of the feedback signal can be from the load circuit itself, from one or more nodes that can detect power received from the PFC switching power supply 100.

[0035] The reference current 1 generated by the peak current controller 123 is provided to the multiplier 125 along with a reference sinusoidal wave signal (reference sinusoidal wave). The reference sinusoidal wave is used by the PFC controller 101 in an effort to achieve a desired power factor, and can be generated based on the AC input signal provided to the PFC converter / switching unit 151. The multiplier 125 is configured to multiply the reference current 1 with the reference sinusoidal wave to generate a product signal (product signal).

[0036] The product signal generated by the multiplier 125 is received by the multiplier 126 along with a voltage error signal (voltage error). Using these two signals, the multiplier 126 is configured to generate a second product, reference current 2. The current regulator 127 is coupled to receive the reference current 2 as well as an indication of the line current (line current) from the PFC converter / switching unit 151. Using the reference current 2 and the line current indication, the current regulator 127 is configured to generate a current regulation signal (current regulation signal).

[0037] In this example, the generated current regulation signal is received by a modulator 128, which can generate or cause generation of a drive signal (Drive). This signal can be used, for example, to control a switch in a PFC converter / switching unit 151, which is used to regulate the DC output power provided by the PFC converter / switching unit 151. In various implementations, the modulator 128 can use pulse width modulation (PWM) to control the switch, in which the width of the pulse is modulated by controlling the amount of time the switch is activated. Some implementations of the modulator 128 can also utilize pulse frequency modulation (PFM), in which the activation frequency of the switch is modulated.

[0038] Figure 2A and Figure 2B A diagram is shown collectively illustrating additional details of one implementation of a PFC switching power supply. In the example of FIG. 2B, the PFC switching power supply 200 includes a PFC converter / switching unit 251 and a PFC controller 201. An example load circuit in the form of a downstream power converter 255 is also illustrated, although it should be understood that this circuit is not part of the PFC switching power supply 200. Similar to the example of FIG. 2A, the PFC controller 201 can be implemented in a separate package from the PFC converter / switching unit 251, although implementations in which a single package includes both units are contemplated by the present disclosure. Figure 2A Figure 1

[0039] ​​The PFC converter / switching unit 251 as shown herein is configured to convert AC input power to DC output power and includes an EMI (electromagnetic interference) filter 205, a bridge rectifier 206, and a DC converter 207. An AC input signal can be received on terminals of a first portion of the EMI filter 205 (which in this particular example includes a protective earth or PE terminal, as well as a fuse F21, a resistor R21, and a capacitor C20), passed through an EMI choke T21, passed through a second portion of the EMI filter 205, and rectified by the bridge rectifier 206. The rectified signal output from the bridge rectifier 206 is received by the DC converter 207, which contains a second EMI filter including an inductor L23, as well as capacitors C24 and C25. The inductor L24 (via diode D23) operates in conjunction with the capacitor C27 to alternately store and release energy to smooth out ripples in the rectified signal to produce a DC voltage. Regulation of the DC voltage occurs in accordance with operation of a switch Q21, and thus regulation of the DC power provided by the PFC converter / switching unit 251. More particularly, the on-time of the switch Q21 can be modulated in accordance with the demands of a downstream load coupled to the PFC switching power supply 200 (e.g., the downstream power converter 255 in this example). The switch Q21 is coupled to a switching node 208, which is formed at the junction of L24 and the anode of diode D23. The cathode of diode D23 is coupled to a DC output node, on which the output DC voltage and DC power are provided to the downstream load.

[0040] Figure 2A Also included are a voltage divider 204, a rectifier 209, and an overcurrent protection circuit 231 coupled between the PFC converter / switching unit 251 and the PFC controller 201. In some embodiments, these circuits / units can be part of the PFC converter / switching unit 251, and thus can be implemented in the same housing.

[0041] The rectifier 209 in the illustrated example is coupled to the EMI filter 205 and includes diodes D21 and D22. The rectifier 209 as shown herein is configured to rectify the EMI filtered AC input signal to produce a modified AC signal. The modified AC signal is provided to the voltage divider 204 for generating an input reference signal received by the reference sine generator 221 via an input reference signal terminal 211. The input reference signal is a divided down version of the modified AC signal, and can provide a basis for generating a reference sine wave by the reference sine generator 221.

[0042] Using the input reference signal, the reference sine generator 221 can generate two output signals for use by downstream units of the PFC controller 201. The first of these two output signals is a reference sine wave signal that is provided to the multiplier 225. The reference sine wave signal can be used by the PFC controller 201 to achieve a desired power factor for the PFC switching power supply 200. Additionally, the reference sine generator 221 in the illustrated embodiment is configured to generate a voltage signal V_RMS that is indicative of the RMS (root mean square) voltage of the AC input signal received by the PFC converter / switching unit 251. The V_RMS signal is provided to the peak current controller 223.

[0043] In addition to receiving the V_RMS signal, the peak current controller 223 in this example is coupled to receive a feedback signal via the feedback terminal 214. The feedback signal in this implementation is taken from a downstream power converter 255 that is coupled to the PFC converter / switching unit 251. More particularly, the feedback signal is indicative of the input power received by the downstream power converter 255. Using the received feedback signal and the V_RMS signal, the peak current controller can generate a first reference current signal, reference current 1. In the illustrated embodiment, the reference current 1 can be generated by dividing the received feedback signal by the V_RMS signal. Both the reference current 1 from the peak current controller 223 and the reference sine wave are received by the multiplier 225, where they are multiplied to generate a product, the product signal.

[0044] The multiplier 226 is coupled to the output of the multiplier 225 as well as the output of the error amplifier 224. In the illustrated embodiment, the error amplifier 224 is coupled to receive a DC sense voltage received from the DC converter 207 (of the PFC converter / switching unit 251) via the DC sense terminal 213 on one of its inputs. The DC sense voltage is generated at the junction of resistors R23 and R24 that form a voltage divider circuit. This voltage divider divides the voltage on the node coupled to the cathode of D23, which carries the DC output voltage. Thus, changes in the DC output voltage are reflected onto the DC sense voltage. The error amplifier 224 is also coupled to receive a reference voltage (V_reference) and is configured to generate a voltage error signal (V_error) based on the difference between the reference voltage and the DC sense voltage. The multiplier 226 in the illustrated embodiment is configured to multiply the voltage error signal by the product signal received from the multiplier 225 to generate a second reference current signal, reference current 2.

[0045] The current regulator 230 is coupled to receive a reference current 2 as well as an indication of the line current in the PFC converter / switching cell 251. The line current indication in this example is received from the junction of the capacitor C28 and the resistor R25 via the line current terminal 215. Using the reference current 2 and the line current indication, the current regulator 230 can generate a current regulation signal (current regulation signal) that is provided to the modulator 228. The modulator 228 can utilize the current regulation signal to generate a modulation signal (modulation) that is provided to the driver 229, which in turn is configured to drive the gate terminal of Q21 via the drive terminal 212 using the drive signal. It is noted that embodiments in which the modulator 228 and the driver 229 are combined into a single unit are possible and contemplated.

[0046] In generating the modulation signal and thus causing the driver 229 to activate or deactivate the switch Q21, the modulator 228 can utilize different modulation schemes, such as PWM or PFM as discussed above. The switching of Q21 can control the exchange of energy between the inductor and the capacitor of the DC converter 207 portion of the PFC converter / switching cell 251.

[0047] The PFC controller 201, and more particularly the modulator 228, is also coupled (via the OCP terminal 216) to an overcurrent protection circuit 231. In response to detecting that the line current in the PFC converter / switching cell 251 exceeds a specified limit, the overcurrent protection circuit 231 is configured to assert an overcurrent signal (overcurrent). In response to the assertion of the overcurrent signal, the modulator 228 is configured to control the modulation signal (and thus the switching of Q21) to bring the line current back within the specified limit.

[0048] It is noted that the PFC controller 201 in various implementations utilizes a control scheme that does not change depending on the operating mode. Thus, for operation in modes such as DCM, CCM, and CrM, the PFC controller 201 can utilize a control scheme that is shared in these different modes. Differences in these operating modes can be reflected in the operation of the modulator (such as the modulator 228 of Figure 2B However, in accordance with the PFC controller of the present disclosure (and with reference to Figure 1 and 2), various signals of the PFC controller and their generation can otherwise remain the same for each of the operating modes.

[0049] Figure 3 are graphs illustrating the operation of one embodiment of a PFC switching power supply. The operation depicted in these graphs can be performed by a PFC switching power supply that includes a PFC controller corresponding to the embodiments discussed above, as well as variations thereof.

[0050] In this example, Figure 3 illustrate steady state operation of embodiments of a PFC switching power supply for a number of different signals utilized or generated in conducting control according to the present disclosure. In Figure 3 the illustrated example, the signals include: an AC input signal 341; a first reference current, reference current 1 342; a second reference current, reference current 2 343; a current regulation signal 344; an error voltage V_error 345; an output voltage 346 (a DC voltage with AC ripple); and an output current 347. Where applicable, these signals can correspond to the signals discussed above during the description of the PFC controller and corresponding control schemes (e.g., error voltage V_error 345 corresponds to the error voltage generated by the error amplifier 224 of Figure 2B

[0051] It is additionally noted that any particular voltages, currents, times, or other values shown in the graphs of Figures 3-5 are presented herein by way of example and are not intended to limit embodiments of the PFC controller or PFC switching power supply in any way. While certain signals can represent current values, they are represented as voltages in these graphs.

[0052] The AC input signal 341 represents an example AC voltage that can be provided to one embodiment of a PFC switching power converter. The reference current 1 342 in the illustrated example can be multiplied by a reference sinusoidal wave (not shown; generated using a rectified version of the AC input signal as discussed above) to generate a product provided to another multiplier, where the product is multiplied by the error voltage V_error 345 to produce the reference current 2 343. The reference current 2343 is used with a signal indicative of the line current (not shown herein) to generate the current regulation signal 344, which can effectively be the error signal produced by the current regulator 230 of an amplifier circuit such as Figure 2B Figure 3 The output voltage signal, output voltage 346, shows a relatively small voltage ripple held in the DC output voltage. As depicted in the graphs of

[0053] Figure 4 are graphs illustrating operation of one embodiment of a PFC switching power supply and reaction to a negative load transient. The operation depicted in these graphs can be conducted by a PFC switching power supply including a PFC controller corresponding to the embodiments discussed above, as well as variations thereof.

[0054] ​AC input voltage 441 is shown in the top plot and corresponds to the input to the PFC switching power supply. Also depicted in the figure is error voltage V_error 445. As shown in this example, a negative load transient 449 causes a dip in both output voltage 446 and output current 447. As can be additionally seen, the output voltage 446 begins to recover over time without overshoot. The change in output voltage 446 as a result of the load transient is reflected to reference current 2 443 in a minimum amount of time after the load transient, indicating a fast transient response (e.g., for one embodiment, within a few microseconds, although this example value is not intended to be limiting). The fast response time in turn results in a relatively fast reflection of the load transient in current regulation signal 444. The load transient is similarly reflected in the value of reference current 1 442.

[0055] Figure 5 are plots illustrating the operation of one embodiment of a PFC switching power supply and the reaction to positive and negative load transients. The operation depicted in these plots can be performed by a PFC switching power supply including a PFC controller corresponding to the embodiments discussed above, as well as variations thereof.

[0056] AC input voltage 541 is shown in the top plot and corresponds to the input to the PFC switching power supply. Also depicted in the figure is error voltage V_error 545. Figure 5 The operation depicted in the plots of Figure 4 is similar to the operation of , but in the opposite direction. A positive load transient 548 does not cause a significant dip in output voltage 546, although there can be some increase in voltage ripple. Output current 547 rises in response to positive load transient 548, as do reference current 1 542, reference current 2 543, and current regulation signal 544. Figure 4 and 5 The fast transient response depicted in may be produced by the control schemes discussed above, in which direct input power to the downstream load circuit (and, thus, direct output power from the PFC switching power supply) is used as a feedback signal, in accordance with the discussion above.

[0057] Figure 6 is a flowchart of a method for operating a PFC controller of a PFC switching power supply. The method 600 can be performed by various embodiments of a PFC controller as discussed elsewhere herein. Embodiments of a PFC controller capable of performing the method 600 but not otherwise disclosed herein are also considered to be within the scope of the present disclosure.

[0058] Method 600 includes regulating the power factor generated by a PFC switching power supply using a controller (block 605). Regulation includes generating a first reference current signal using a peak current controller and a feedback signal indicating the amount of power provided by the PFC switching power supply (block 610). Regulation in method 600 also includes multiplying a reference sine wave signal with the first reference current signal using a first multiplier to generate a product signal, wherein the reference sine wave signal is based on an AC input signal received by the PFC switching power supply (block 615); and multiplying the product signal with a voltage error signal using a second multiplier to generate a second reference current signal (block 620). Regulation also includes creating a current regulation signal using the second reference current signal and a line current in the PFC switching power supply using a current regulator (block 625); and controlling the assertion time of a signal applied to a drive terminal of the PFC switching power supply using the current regulation signal using a modulator (block 630).

[0059] In various embodiments, the method includes implementing a control scheme for each of the plurality of operating modes using a controller that is shared across the plurality of operating modes. In one implementation of the controller, the plurality of operating modes includes a discontinuous current mode. The implementation of the controller may also include a plurality of operating modes operating in a continuous current mode and / or a critical current mode.

[0060] In some implementations of a controller capable of performing method 600 , controlling the assertion time of a signal applied to a drive terminal of the PFC switching power supply includes a modulator using pulse width modulation (PWM).

[0061] The method as performed by some controllers according to the present disclosure may include generating a reference sine wave signal using a reference signal generator, and further including generating a voltage signal indicative of a root mean square (RMS) voltage of an AC input signal using the reference signal generator. The method as implemented in such a controller may further include dividing the feedback signal by the voltage signal using a peak current controller to generate a first reference current signal.

[0062] The method as performed in some embodiments of the controller may include generating a voltage error signal using an error amplifier, a reference voltage, and a DC sense voltage received from the PFC switching power supply.

[0063] Figure 7 700 is a flow chart illustrating another method for operating one embodiment of a PFC switching power supply. Method 700, as discussed herein, can be performed by various embodiments of the PFC switching power supply and corresponding PFC controller, as discussed above. Embodiments of PFC switching power supplies and PFC controllers capable of performing method 700 but not explicitly discussed herein are also considered to fall within the scope of this disclosure.

[0064] The method 700 includes operating a PFC controller for a PFC switching power supply in different modes, where the different modes include discontinuous current mode, critical current mode, and continuous current mode (block 705). The method 700 also includes maintaining a shared control scheme for operating in each of these different modes (block 710).

[0065] Many of the electrical connections in the drawings are shown as direct connections, but in actual practice the connections can be made through intervening devices, such as resistors, capacitors, inductors, optoelectronic devices, and the like. The intervening devices are not shown in the drawings as they are not essential to the principles of the present disclosure.

[0066] The foregoing discussion is intended to illustrate principles of the present disclosure and various implementations. Numerous variants and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. The following claims are to be interpreted in the broadest and most liberal manner to encompass all such variants and modifications.

Claims

1. A PFC controller for a power factor correction (PFC) switching power supply, characterized in that: The PFC controller includes: a peak current controller configured to receive a feedback signal indicative of an input power of a downstream power converter on a feedback terminal, wherein the peak current controller is further configured to generate a first reference current signal using the feedback signal; a first multiplier configured to generate a product signal based on a product of a reference sinusoidal wave signal and the first reference current signal, wherein the reference sinusoidal wave signal is based on an AC input signal received by the PFC switching power supply; a second multiplier configured to create a second reference current signal based on the product signal and a voltage error signal; a current regulator configured to generate a current regulation signal using the second reference current signal and a line current of the PFC switching power supply; and a modulator configured to regulate an output power generated by the PFC switching power supply using the current regulation signal, wherein to regulate the output power, the modulator is configured to control an assertion time of a signal applied to a drive terminal.

2. The PFC controller of claim 1, wherein, A control scheme used in each of a plurality of operating modes of the PFC controller is shared among the plurality of operating modes.

3. The PFC controller of claim 2, wherein, The plurality of operating modes includes a discontinuous current mode, a critical current mode, and a continuous current mode.

4. The PFC controller of claim 1, wherein, The modulator is configured to control the assertion time of the signal applied to the drive terminal using pulse width modulation (PWM), wherein the drive terminal is coupled to a control terminal of a switch of the PFC switching power supply.

5. The PFC controller of claim 1, wherein, The PFC controller further includes a reference signal generator configured to generate the reference sinusoidal wave signal using an input reference signal, wherein the reference signal generator is further configured to generate a voltage signal indicative of a root mean square (RMS) voltage of the AC input signal.

6. The PFC controller of claim 5, wherein, To generate the first reference current signal, the peak current controller is configured to divide the feedback signal by the voltage signal.

7. The PFC controller of claim 1, wherein, The PFC controller further includes an error amplifier configured to generate the voltage error signal based on a reference voltage and a DC sense voltage received from the PFC switching power supply.

8. The PFC controller of claim 1, wherein, The PFC controller further includes an overcurrent protection unit, wherein the modulator is configured to cause the line current to be limited in response to an overcurrent condition being detected by the overcurrent protection unit.

9. The PFC controller of claim 1, wherein, The PFC controller further includes a driver configured to control activation of a switch of the PFC switching power supply based on a control signal received from the modulator.

10. A method for operating a power factor correction (PFC) switching power supply, characterized by, The method includes: regulating, using a controller, an output power generated by the PFC switching power supply, wherein the regulating includes: generating, by a peak current controller and using a feedback signal indicative of an amount of power drawn by a downstream load, a first reference current signal; multiplying, using a first multiplier, a reference sinusoidal wave signal with the first reference current signal to generate a product signal, wherein the reference sinusoidal wave signal is based on an AC input signal received by the PFC switching power supply; multiplying the product signal with a voltage error signal using a second multiplier to generate a second reference current signal; creating a current regulation signal using the second reference current signal and a line current in the PFC switching power supply through a current regulator; and controlling an assertion time of a signal applied to a drive terminal of the PFC switching power supply through a modulator and using the current regulation signal.

11. The method of claim 10, wherein, The method further includes implementing, using the controller, a control scheme shared in each of a plurality of operating modes.

12. The method of claim 11, wherein, The plurality of operating modes includes a discontinuous current mode.

13. The method of claim 11, wherein, The plurality of operating modes includes a continuous current mode.

14. The method of claim 11, wherein, The plurality of operating modes includes a critical current mode.

15. The method of claim 10, wherein, Controlling the assertion time of the signal applied to the drive terminal of the PFC switching power supply includes the modulator using pulse width modulation, PWM.

16. The method of claim 10, wherein, The method further includes generating, using a reference signal generator, the reference sinusoidal wave signal, and wherein the method further includes generating, using the reference signal generator, a voltage signal indicative of a root mean square, RMS, voltage of the AC input signal.

17. The method of claim 16, wherein, The method further includes dividing, using the peak current controller, the feedback signal by the voltage signal to produce the first reference current signal.

18. The method of claim 10, wherein, The method further includes producing, using an error amplifier, the voltage error signal based on a reference voltage and a DC sense voltage received from the PFC switching power supply.

19. A power factor correction (PFC) switching power supply, characterized by, The PFC switching power supply includes: a filter configured to produce a filtered AC signal by filtering an AC input signal received by the PFC switching power supply; a rectifier configured to rectify the filtered AC signal to produce a rectified signal; an inductor coupled between the rectifier and a switching node; an electronically controlled switch having a first terminal coupled to the switching node, a second terminal coupled to a reference node, and a control terminal; and a PFC controller having an input reference signal terminal, a feedback input terminal, and a control output terminal, wherein the PFC controller is configured to regulate an output power produced by the PFC switching power supply, wherein the PFC controller includes: a reference signal generator configured to produce a reference sinusoidal wave signal using an input reference signal received via the input reference signal terminal, and further configured to produce a voltage signal indicative of a root mean square, RMS, voltage of the AC input signal using the input reference signal; a peak current generator configured to receive a feedback signal indicative of a power produced by the PFC switching power supply on a feedback terminal, and further configured to generate a first reference current signal by dividing the feedback signal by the voltage signal; a first multiplier configured to generate a product signal based on a product of the reference sinusoidal wave signal and the first reference current signal; an error amplifier configured to output a voltage error signal based on a reference voltage and a DC sense voltage indicative of a DC output voltage generated by the PFC switching power supply; a second multiplier configured to create a second reference current signal based on the product signal and the voltage error signal; a current regulator configured to generate a current regulation signal using the second reference current signal and a line current from the PFC controller; a modulator configured to produce a modulation control signal based on the second reference current signal; and a driver coupled to the control terminal, wherein the driver is configured to control a turn-on time of the switch based on the modulation control signal; wherein a control scheme used in each of a plurality of operating modes of the PFC switching power supply is shared across the plurality of operating modes.

20. The PFC switching power supply of claim 19, wherein, the plurality of operating modes includes a discontinuous current mode, a continuous current mode, and a critical current mode.

Images