Resonant power converter and controlled capacitor discharge

Abstract

The present disclosure relates to resonant power converters and controlled capacitor discharge. A controller can be configured to control a plurality of switches in a resonant power converter during a first mode of operation and implement a second mode of operation in which the plurality of switches are stopped from being switched on and off. In a first example, based on a duration associated with operation of the resonant power converter, the controller can be configured to control the plurality of switches in the resonant power converter to discharge a resonant capacitor of the resonant power converter. In a second example, during the second mode of operation, the controller can be configured to control a first switch of the plurality of switches to discharge the resonant capacitor of the resonant power converter. In a third example, based on a monitored amplitude of a current through a first switch of the plurality of switches, the controller can be configured to control the first switch of the plurality of switches to discharge the resonant capacitor of the resonant power converter.

Description

Technical Field

[0001] This application relates to controllers, such as controllers associated with resonant power converters, resonant power converters including such controllers, and corresponding methods for operating such resonant power converters. Background Technology

[0002] Power converters are used in many applications to convert input electrical power into output electrical power suitable for the corresponding appliance or device in terms of voltage, current, or both. For example, chargers for smartphones or tablets, or power supplies for computers, laptops, and many other devices, convert input power (typically AC power) into appropriate output power (voltage and current). AC power is typically AC (alternating current) power, where voltage ranges from 100 volts to 300 volts depending on the country, and the required output voltage may range from 3 volts to 20 volts DC (direct current) depending on the application.

[0003] Sometimes, conventional power converters include multiple stages, such as a so-called power factor correction stage, which provides an intermediate voltage (also known as a bus voltage), and a second stage that performs actual regulation to the desired output voltage.

[0004] One type of power converter is the resonant power converter, in which, during operation, typically in a first stage, power is supplied to a resonant circuit comprising a capacitor (referred to herein as a resonant capacitor) and at least one inductor, and in a second stage, power is supplied to the output side of the resonant converter. At the output side, the output signal is typically provided via an output capacitor. Examples of such resonant converters include active clamp flyback (ACF) converters or asymmetric half-bridge flyback (AHBF) converters. Summary of the Invention

[0005] This disclosure includes the observation that, under certain conditions, conventional power converters may be required or may be forced to stop operating. Such conditions will be referred to herein as abnormal conditions and may include, for example, a disconnection from the input voltage (such as mains voltage) (intentionally or due to a power outage), shutdown of the device including the power converter, overcurrent conditions, short-circuit conditions, etc. Under such abnormal conditions, in conventional solutions, so-called primary-side switches (e.g., high-side and low-side switches provided in a half-bridge configuration) are turned off to prevent overvoltage or overcurrent conditions at the output. When the power converter is restarted, residual charge may cause undesirable current surges. Figure 1 An example of a conventional resonant power converter is shown.

[0006] As discussed earlier, a conventional hybrid flyback power converter can be configured to include a resonant capacitor on the primary side, which is effectively connected via a transformer to the output capacitor on the secondary side for energy transfer during operation. This disclosure also includes the observation that the corresponding resonant capacitor on the primary side is susceptible to damage. For example, during certain periods when the converter is not switching but the primary-side capacitor Cr remains charged, the output capacitor on the secondary side is discharged. Typically, when the resonant power converter switches between operating modes, there is an effective low-impedance path connecting the two capacitors (such as capacitor CR to capacitor Cout), which can result in high currents that may damage the converter's switches, particularly. Figure 1 The example shows the low-side switch.

[0007] The examples in this paper provide novel and improved operation of the corresponding resonant power converter.

[0008] More specifically, in one example, the device (such as a resonant power converter, a hybrid flyback converter, etc.) or other suitable entity includes a controller. This controller can be configured (also known as operable to): control the on / off settings of multiple switches in the resonant power converter during a first operating mode to convert the input voltage to the output voltage; implement a second operating mode in response to a first feedback to stop switching the multiple switches on and off; and control the multiple switches in the resonant power converter to discharge the resonant capacitor of the resonant power converter based on the duration associated with the operation of the resonant power converter.

[0009] In another example, the duration is a measurement of the second operating mode implemented when switching multiple switches is stopped.

[0010] In another example, the multiple switches in the resonant power converter include a first switch and a second switch arranged in series; and the controller is further configured to derive a metric for controlling the first switch based on the duration. This metric can indicate the timing associated with activating the first switch to discharge the resonant capacitor of the resonant power converter. For example, the metric can indicate the number of pulses required to activate the first switch, resulting in the discharge of the resonant capacitor. The magnitude of the metric used to control the first switch can be proportional to the magnitude of the duration.

[0011] In yet another example, multiple switches include a first switch and a second switch, with the first switch connected in series with a resonant capacitor. The controller can be configured to: during the discharge of the resonant capacitor, when the second switch is controlled to the off state, control the switching operation of the first switch to discharge the resonant capacitor before controlling the power converter again in the first operating mode.

[0012] Another example discussed herein includes a controller configured to: when in a second operating mode, measure the duration for which switching of a plurality of switches is stopped; based on the measured duration, control the timing of activating and deactivating a first switch of the plurality of switches to discharge a resonant capacitor; and wherein the cumulative on-time associated with the controlled timing of the first switch used to discharge the resonant capacitor is based on the measured duration.

[0013] In another example still discussed herein, the controller is configured to control multiple switches in the resonant power converter to discharge the resonant capacitor in response to receiving a second feedback, wherein the second feedback indicates that the amplitude of the output voltage is less than the setpoint reference voltage.

[0014] In another example, the plurality of switches includes a first switch and a second switch connected in series in a first series circuit path, wherein the first series circuit path of the plurality of switches is configured to control the transfer of current received from the input voltage to the resonant capacitor; the resonant power converter may also be configured to include a primary winding connected in series with the resonant capacitor in a second series circuit path; the second series circuit path may be connected in parallel with the second switch; and the primary winding may be magnetically coupled to a secondary winding for generating an output voltage.

[0015] In another example discussed herein, the device (such as a resonant power converter, a hybrid flyback converter, etc.) or other suitable entity includes a controller. This controller may be configured (also known as operable to): control a plurality of switches in the resonant power converter during a first operating mode to convert an input voltage to an output voltage; implement a second operating mode, in response to a first feedback, controlling the plurality of switches, including a first switch and a second switch; and during the second operating mode, controlling the second switch to an off state while simultaneously controlling the first switch to operate between an off state and an on state to discharge the resonant capacitor of the resonant power converter.

[0016] In one example, the first feedback indicates that the output voltage amplitude is greater than a threshold level. The controller can also be configured to, after a second operating mode, resume operation of the resonant power converter in the first operating mode in response to receiving the second feedback. The second feedback may indicate that the output voltage is less than a threshold level (such as a setpoint reference voltage). In this case, the controller can be configured to switch the operation of the resonant power converter from the first operating mode to the second operating mode in response to detecting that the output voltage amplitude is greater than the threshold level. Alternatively, the controller can be configured to switch the operation of the resonant power converter from the second operating mode to the first operating mode in response to detecting that the output voltage amplitude is less than the threshold level.

[0017] In another example, the operation of the resonant power converter in the second operating mode maintains the magnitude of the first voltage across the resonant capacitor with respect to the magnitude of the output voltage.

[0018] In another example, the controller can be configured to, after the second operating mode, resume the first operating mode in which multiple switches switch between on / off states to convert the input voltage into the output voltage.

[0019] As discussed previously, multiple switches can be configured to include a first switch and a second switch connected in series in a first series circuit path, wherein the first series circuit path is configured to control the transmission of current received from the input voltage. The resonant power converter can also be configured to include a transformer, wherein the transformer includes a primary winding and a secondary winding magnetically coupled to the primary winding. The primary winding can be connected in series with a resonant capacitor and a second series circuit path. The second series circuit path can be connected in parallel with a second switch. The current through the primary winding results in a corresponding current through the secondary winding, wherein the current to the secondary winding generates the output voltage.

[0020] In yet another example discussed herein, the device (such as a resonant power converter, a hybrid flyback converter, etc.) or other suitable entity includes a controller. This controller can be configured to: control multiple switches in the resonant power converter to switch between on / off states during a first operating mode to convert an input voltage to an output voltage; implement a second operating mode that stops switching the multiple switches on / off in response to a first feedback; and control the first switch among the multiple switches to discharge the resonant capacitor of the resonant power converter based on the magnitude of the current flowing through the first switch among the multiple switches.

[0021] In one example, a first switch is placed in a series circuit loop; the series circuit loop can be configured to include a combination of the first switch, the primary winding of a transformer, and a resonant capacitor.

[0022] In another example, the controller can be configured to control the first switch to discharge the resonant capacitor after the second operating mode is implemented and before the first operating mode in which multiple switches switch between on / off states is restored.

[0023] According to a further example discussed herein, multiple switches can be configured to include a second switch, wherein the first switch and the second switch are connected in series. Controlling the first switch to discharge the resonant capacitor by the controller includes: deactivating the second switch to the off state when the first switch is switched between an on and off state.

[0024] Further examples of this document include a controller configured to: when a second switch of a plurality of switches is deactivated to an off state; monitor the magnitude of the current through the first switch; compare the magnitude of the current to a current threshold level; and switch the first switch between an on state and an off state until the magnitude of the current through the first switch drops below the current threshold level. The controller can be configured to, in response to detecting that the magnitude of the current exceeds the current threshold level, resume a first operating mode that switches the plurality of switches between on and off.

[0025] Further examples of this paper include a controller configured to control a first switch of a plurality of switches to discharge a resonant capacitor in response to receiving a second feedback indicating that the output voltage amplitude has dropped below a voltage threshold level.

[0026] As discussed previously, multiple switches can be configured to include a first switch and a second switch disposed in a first series circuit path, wherein the first series circuit path is configured to control the transmission of current received from the input voltage. The resonant power converter can also be configured to include a transformer, wherein the transformer includes a primary winding and a secondary winding magnetically coupled to the primary winding. The primary winding can be connected in series with a resonant capacitor and a second series circuit path. The second series circuit path can be connected in parallel with a second switch. The current through the primary winding results in a corresponding current through the secondary winding, wherein the current to the secondary winding generates the output voltage.

[0027] The amplitude of the current can be the peak amplitude of the current to the first switch.

[0028] In another example, the magnitude of the current can be measured based on the voltage across a resistor connected in series with the resonant capacitor, where the voltage is proportional to the magnitude of the current.

[0029] These, and other more specific examples, will be disclosed in more detail below.

[0030] It should also be noted that while the examples discussed herein are applicable to the fabrication of circuit components such as power converter components, the concepts disclosed herein can be advantageously applied to any other suitable topology.

[0031] Furthermore, it should be noted that although each of the different features, techniques, configurations, etc., described herein may be discussed in different places within this disclosure, it is intended that each concept may optionally be implemented independently of or in combination with each other, where appropriate. Therefore, one or more inventions described herein can be embodied and viewed in many different ways.

[0032] It should also be noted that this initial discussion of the examples (a brief description of the examples) is intentionally not to specify every example and / or aspect of incremental novelty in this disclosure or the claimed invention(s). Rather, this brief description presents only general examples and corresponding points of novelty relative to conventional art. For additional details and / or possible perspectives regarding the (arrangement) of the invention(s), the reader may refer to the detailed description section (which is a summary of the examples) and the corresponding figures of this disclosure discussed further below. Attached Figure Description

[0033] Figure 1 This is an example diagram of a power converter circuit that implements one or more novel control techniques to convert input voltage to output voltage, as discussed in this article.

[0034] Figure 2 This is an example timing diagram illustrating the generation of control signals based on zero-crossing detection as discussed herein.

[0035] Figure 3 This is an example diagram illustrating the potential impacts associated with operating power converters as discussed herein.

[0036] Figure 4 This is an example diagram illustrating the potential impacts associated with operating power converters as discussed herein.

[0037] Figure 5A and Figure 5B This is an example timing diagram illustrating the implementation of multiple control pulses to discharge energy stored in a resonant capacitor, as discussed in this paper.

[0038] Figure 6 This is an example timing diagram illustrating the implementation of multiple switching control pulses to discharge energy stored in a resonant capacitor, as discussed herein.

[0039] Figure 7 This is an example circuit diagram illustrating a resonant power converter, as discussed previously, which includes a supplementary resistor to monitor the magnitude of the current through the resonant capacitor and windings.

[0040] Figure 8 This is an example diagram illustrating the implementation of multiple switching control pulses to discharge energy stored in a resonant capacitor, as discussed in this article.

[0041] Figure 9 This is an example diagram illustrating an implementation of a resonant power converter as discussed in this article.

[0042] Figure 10 This is an example diagram illustrating a first method, as discussed herein, of implementing multiple switching control pulses to discharge energy stored in a resonant capacitor.

[0043] Figure 11 This is an example diagram illustrating a second method, as discussed herein, of implementing multiple switching control pulses to discharge energy stored in a resonant capacitor.

[0044] Figure 12 This is an example diagram illustrating a third method, as discussed herein, of implementing multiple switching control pulses to discharge energy stored in a resonant capacitor.

[0045] The foregoing and other purposes, features, and advantages of the examples herein will become apparent from the following more specific description, as illustrated in the accompanying drawings, in which the same reference characters refer to the same parts throughout the different views. The drawings are not necessarily drawn to scale and are intended to illustrate examples, principles, concepts, etc. Detailed Implementation

[0046] Now, please refer to the attached diagram for more specific details. Figure 1 This is an example diagram of a power converter circuit that provides the conversion from input voltage to output voltage, as discussed in this article.

[0047] like Figure 1 As shown, the power converter 100 (such as a resonant power converter) can be implemented as a so-called asymmetric half-bridge flyback power converter, which includes a controller 140. The power converter 100 also includes an EMI (electromagnetic interference) filter 104, an input capacitor CIN, a switch 121 (S1), a switch 122 (S2), a resistor R1, a transformer T1, a resonant capacitor CR, a diode D1, a feedback controller 141, and an output capacitor Cout.

[0048] It should be noted that transformer T1 includes one or more windings, such as primary winding 161, secondary winding 162, and auxiliary winding 163. Each of the windings is magnetically coupled to each other via the core of transformer T1.

[0049] Typically, during power conversion operation, the EMI filter 140 receives the AC input voltage Vac and converts it into the input voltage 121 (also known as Vin), which is typically the DC voltage stored in the input capacitor Cin.

[0050] As discussed herein, controller 140 controls the operation of switches 121 and 122 to convert input voltage 121 into a corresponding output voltage 123 from secondary winding 162. More specifically, the control of switches 121 and 122 controls the current Ihb through primary winding 161 and resonant capacitor Cr. As discussed herein, at appropriate times, controlling the current Ihb through primary winding 161 results in a corresponding current Isec through secondary winding 162, which produces the output voltage 123 supplying power to load 118.

[0051] In one aspect, transformer T1 provides current isolation between the primary and secondary sides of power converter circuit 100. For example, the primary-side controller 140 and corresponding circuitry (such as primary winding 161 and auxiliary winding 163) and the corresponding circuitry on the left side of transformer T1 are referenced to ground reference 191.

[0052] The secondary winding 162 and the corresponding circuitry on the right side of transformer T1 are referenced to ground reference 192. In one example, ground reference 191 is electrically isolated from ground reference 192.

[0053] Therefore, on the primary side, the power converter circuit 100 includes a high-side switch 121 (S1) and a low-side switch 122 (S2), both of which can be represented as transistor switches, coupled in series between the terminals of the input voltage source 120 that supplies the input voltage Vin to the switch 121.

[0054] Therefore, as shown in the figure, the drain node D of switch 121 receives the input voltage Vin; the source node S of switch 121 is directly coupled to the drain node D of switch 122; the source node S of switch 122 is directly connected to resistor R1; resistor R1 is directly connected between the source node of switch 122 and ground reference 191.

[0055] The shunt resistor R1 can be used as a component for measuring the current flowing on the primary side of the power converter 10. The current through the resistor R1 can be measured by the controller 140 via the input pin CS of the controller 140, which is directly coupled to the node connecting the low-side switch 122 and the shunt resistor R1.

[0056] It should also be noted that the low-side switch 122 is coupled in a closed loop to the inductor Llk (a virtual leakage inductance associated with the primary winding 161), the primary winding 161 (Lm) of the transformer T1, and the resonant capacitor Cr.

[0057] The current through inductors Llk and Lm is designated as current Ihb. The voltage across the low-side switch 122 in ground reference 191 is typically voltage Vhb. The high-side switch 121 is controlled by controller 140 via outputting a corresponding control signal HSGD to terminal HSGD of the gate node G of switch 121. The low-side switch 122 is controlled by controller 140 via outputting a corresponding control signal LGSD to terminal LGSD of the gate node G of switch 122.

[0058] During normal operation, the high-side switch 121 and the low-side switch 122 alternately open and close according to the resonant frequency defined by the inductance associated with Llk and Lm and the capacitance associated with the resonant capacitor Cr.

[0059] Therefore, the inductors Llk and Lm together with the resonant capacitor Cr form a resonant circuit.

[0060] In a normal operation of the power converter 100, during the first phase of each switching cycle, the high-side switch 121 is closed (also known as the on state) and the low-side switch 122 is open (also known as the off state), allowing energy to be transferred from the input voltage source Vin to the resonant circuit comprising the primary winding 161 and the resonant capacitor Cr. The resonant capacitor Cr is charged.

[0061] In the second stage, the resonant capacitor Cr is discharged. For example, the high-side switch 121 is opened and the low-side switch 122 is closed in the second stage, causing energy to be transferred to the secondary side via the transformer T1, so that the secondary current Isec flows through the secondary winding 162 and the diode D1. In this example, the secondary current Isec is rectified by the diode D1 and filtered by the output capacitor Cout to provide the output current Iout (124) and the output voltage Vout to the load 118.

[0062] In one example, diode D1 may represent the diode of the MOSFET of the synchronous rectification (SR) circuit provided on the secondary side of the power converter 100.

[0063] Furthermore, it should be noted that the power converter 100 can be configured to include an auxiliary winding 163 (also referred to as Laux) disposed on the primary side of the transformer T1. One axial end of the auxiliary winding 163 is directly connected to the input pin ZCD of the controller 140, while the other axial end of the auxiliary winding 163 is directly connected to the ground reference 191.

[0064] Furthermore, it should be noted that during normal operation, the voltage received at terminal ZCD can be used to control switches 121 and 122 in a conventional manner, for example, to achieve so-called zero-voltage switching. In other words, controller 140 can be configured to monitor the condition that the current flowing through primary winding 161 is 0 or the voltage at input pin ZCD is 0, and control switches 121 and 122 to transition between on and off states, and vice versa. More specifically, in one example, the output voltage 123 or output current 122 can be regulated based on the voltage at terminal ZCD of controller 140 and / or the voltage at terminal CS of controller 140.

[0065] The controller 140 can be configured to receive feedback 175 associated with the output voltage Vout and / or output current Iout generated from the secondary side of the power converter 100 (secondary winding 162, diode D1, etc.), for example via an optocoupler (such as the controller 141) that is currently isolated by the transformer T1, also in a conventional manner.

[0066] Generally speaking, as mentioned above, operation and regulation during the normal operation of a power converter can be performed in any suitable manner.

[0067] It is desirable to provide appropriate feedback 175 from the secondary side of the power converter 100 to the controller 140. Typically, if the feedback 175 output from controller 141 to controller 140 indicates that the magnitude of the output voltage 123 is lower than the setpoint reference voltage 179, controller 140 controls switches 121 and 122 to increase the energy supplied to the primary winding 161, resulting in an increase in the secondary current Isec (increasing the magnitude of the output voltage 123). Conversely, if the feedback 175 indicates that the magnitude of the output voltage 123 is higher than the setpoint reference voltage 179, controller 140 controls switches 121 and 122 to decrease the energy supplied to the primary winding 161, resulting in a decrease in the secondary current Isec (decreasing the magnitude of the output voltage 123).

[0068] There may be situations where the power converter 100 experiences what is called an abnormal condition, which can be indicated by feedback 175 supplied from controller 141 to controller 140.

[0069] Note that during so-called abnormal conditions, the normal operation of the power converter 100 may be terminated for various reasons. In one example, the condition that causes the termination of normal operation is referred to herein as an abnormal condition. Such abnormal conditions may include error conditions, such as overvoltage or overcurrent, and the intentional termination of the normal operation of the power converter 100 in converting the input voltage to the output voltage, for example, when the device including the power converter is turned off or placed in power-saving mode, at which time the power converter operation is not required.

[0070] Another example of an abnormal condition is the disconnection of the power converter from its input power source. This could be due to fault conditions (such as a power outage or insufficient voltage) or intentional circumstances, such as the user unplugging the device from the main power outlet.

[0071] Such anomaly detection can be carried out in any suitable manner.

[0072] For example, various suitable methods exist for monitoring the output current or output voltage for overcurrent conditions, short-circuit conditions, etc., and the input power supply can also be monitored, for example, by monitoring the input voltage. Therefore, the detection of abnormal conditions will not be described in detail. Instead, the embodiments described herein will focus on the situation after an abnormal condition occurs.

[0073] Conventionally, during so-called abnormal conditions, the power converter is simply turned off; for example, both the high-side and low-side switches of the power converter are set to the off state. In contrast to conventional techniques, the examples in this paper include a novel method of discharging the resonant capacitor of the power converter.

[0074] Therefore, when the amplitude of the output voltage 123 is detected to be higher than the corresponding setpoint reference voltage 179, an abnormal condition may occur, and the controller 140 needs to stop activating the high-side switch 121 to prevent the amplitude of the output voltage 123 from becoming even higher.

[0075] In one example, when an abnormal condition occurs, controller 140 terminates normal operation. Unlike conventional power converter controllers and power converters, when normal operation is terminated, controller 140 does not simply turn off switches S1 and S2. Instead, as discussed herein, controller 140 controls the low-side switch S2 to close for one or more time periods, while the high-side switch 122 remains closed, to discharge capacitor Cr. In other words, pulsed switching of the low-side switch 121 is used to discharge the resonant capacitor Cr. After this discharge, if desired, the low-side switch 122 can be turned off, leaving power converter 100 in the off state. Alternatively, operation of power converter 100 can resume, with both switches 121 and 122 being switched on and off again.

[0076] As will be explained in more detail below, implementing this discharge technique can prevent current surges caused by the charge stored in the resonant capacitor Cr when the power converter 100 is restarted later. For example, in some cases and implementations, the power converter 100 may automatically restart after a predefined time period (e.g., 3 seconds) following the occurrence of an abnormal condition. This technique is used, for example, when the abnormal condition is an error condition (such as an overcurrent condition, a drop in input voltage Vin, or a short circuit condition), which may be temporary.

[0077] Figure 2 This is an example diagram illustrating the generation of control signals based on zero-crossing detection as discussed in this article.

[0078] It is important to note that, as shown in Figure 5 below... Figure 6 and Figure 8The diagram illustrates the operation of the power converter 100 in a mode where switch 122 is pulsed on and off while switch 121 is set to the off state. Switching of switch 122 causes the energy stored in the resonant capacitor Cr to discharge through the primary winding to the secondary winding, providing better synchronization between the voltage in capacitor Cr and the output voltage 123.

[0079] generally, Figure 2 The diagram illustrates the operation of the power converter 100 in a mode that discharges the resonant capacitor Cr. This discharge mode is similar to that shown in Figure 5. Figure 6 and Figure 8 The discharge of the resonant capacitor is discussed in the article.

[0080] and Figure 2 A noteworthy aspect associated with the illustrated repetitive discharge cycle is that the controller 140 operates in a so-called zero-voltage switching (ZVS) mode to prevent damage to switches 121 and 122.

[0081] It should also be noted that Figure 2 The waveform shown is presented as a non-limiting example. Different waveforms can be implemented to achieve the same result.

[0082] More specifically, Figure 210 illustrates the repeated activation of switch 122 via generating a control signal LSGD output from controller 140 to the gate node G of switch 122. A logic high (H) state of control signal LSGD causes switch 122 to activate (closed) to the on state; a logic low (L) state of control signal LSGD causes switch 122 to deactivate (open) to the off state.

[0083] Curve 41 and Figure 212 (timing diagram) illustrate the change of current Ihb amplitude over time; curve 42 in Figure 214 (timing diagram) illustrates the auxiliary voltage Vaux received from the auxiliary winding Lax at terminal ZCD; curve 43 in Figure 216 (timing diagram) represents the voltage Vhb across switch S2, and curve 44 and Figure 216 represent the voltage across resonant capacitor Cr.

[0084] exist Figure 2 In the example, according to curve 40, the pulses during the closure of the low-side switch 122 have the same duration. When the low-side switch is closed, the absolute amplitude of Ihb increases in the negative direction, from approximately 0 to various negative values. When the low-side switch 122 is open, the current Ihb crosses again or reaches 0.

[0085] exist Figure 4 In the example, the next pulse immediately follows, i.e., the low-side switch S2 closes again when Ihb reaches or approaches 0. In some examples, this current Ihb can be directly measured as the voltage across the shunt resistor R1. For example, in Figure 4 In the numerical examples, the threshold can be set between 0 and -0.1 volts, or, for example, the low-side switch S2 closes again once this threshold is exceeded. However, in the example shown, the voltage Vaux is used to control the switching of the low-side switch. Figure 4 It can also be seen, and as indicated by arrow 45, that curve 42 is essentially synchronized with pulse curve 40, i.e., voltage Vaux exhibits pulse-like behavior corresponding to the pulses of curve 40. When Vaux rises again, this indicates that the primary winding Lm is demagnetized (and therefore the current Ihb is zero), at which point the next pulse of curve 40 can immediately follow. Therefore, in some examples, the start of the pulse is determined based on Vaux.

[0086] Alternatively, the demagnetizing current can be measured at the midpoint between the high-side switch 121 and the low-side switch 122, and regulation can be performed based on this current, for example, turning the high-side switch 121 back on after the demagnetizing current is zero or the difference from zero does not exceed a predefined threshold.

[0087] Therefore, as Figure 2 As shown in curve 44 (voltage across resonant capacitor Cr), the repeated pulsed switching on and off of switch 122 causes the amplitude of voltage Vcr across resonant capacitor Cr to gradually decrease.

[0088] Similarly, as can be seen from curve 43 (voltage Vhb), when the low-side switch 122 is closed, the voltage Vhb across the low-side switch 122 drops to approximately 0, and when the switch 122 is opened, the voltage Vhb rises back to a higher voltage (140 volts in this example).

[0089] It can also be seen that, according to curve 42, the peak of Vaux (input to pin ZCD of controller 140) decreases in approximately the same manner as curve 44 (voltage across capacitor CR). Therefore, as described above, the auxiliary voltage Vaux received at terminal ZCD of controller 140 can also be used as a measurement of the voltage across resonant capacitor Cr according to curve 44.

[0090] As can be seen from curve 41, the maximum absolute current decreases with time as the discharge of the resonant capacitor Cr increases. In some examples, this can be used to increase the duration of the low-side switch 122 being closed as the capacitor charge decreases, i.e., the pulse length increases in contrast to the pulse of equal length in curve 40.

[0091] For example, as indicated by time arrow 46, the pulse can be set according to the peak voltage of the auxiliary voltage Vaux, such that the duration increases as the peak voltage of Vaux decreases (and therefore as the charge on the capacitor Cr decreases).

[0092] In another example, the voltage across capacitor Cr can be directly measured and used to adjust the pulse length. In other examples, the amplitude of the measured negative current Ihb can be used to adjust the pulse duration. In this way, faster discharge can be achieved in some examples.

[0093] In addition, it should be noted that when... Figure 2 As illustrated, when the voltage Vcr of capacitor Cr is discharged, contrary to the normal operation of the power converter, the high-side switch 121 remains off. Due to this state, virtually no energy is transferred to the secondary side and no output occurs, but the energy stored in the resonant capacitor is transferred back towards the input voltage. This... Figure 3 and Figure 4 The diagrams in the middle show that they illustrate Figure 1 The power converter 100 is part of it.

[0094] Figure 3 This is an example diagram illustrating the potential impacts associated with operating power converters as discussed herein.

[0095] generally, Figure 3 The diagram shows the current 310 flowing through the combination of switch 122, primary winding 161, and resonant capacitor Cr when switch S2 is closed (conducting state) based on the high voltage at the gate node S of switch 122.

[0096] Figure 4 This is an example diagram illustrating the potential impacts associated with operating power converters as discussed herein.

[0097] generally, Figure 4 The diagram illustrates a phase where both high-side switch 121 and low-side switch 122 are set to the off state, specifically during the low-cycle period when the amplitudes of the control signals applied to the gate nodes of both switches 121 and 122 are set to logic low voltage. In this case, as indicated by arrow 52, ​​current flows from the resonant capacitor Cr through the primary winding line 61 and the body diode (also known as the parasitic diode) of switch 121 toward the input voltage Vin.

[0098] Figure 5A and Figure 5B This is an example timing diagram illustrating the implementation of multiple pulses to discharge energy stored in a resonant capacitor, as discussed herein.

[0099] In this example, the controller 140 operates in different power converter modes M1, M2 and M3 based on the state of the feedback signal 175.

[0100] During normal mode M1 prior to time T50, controller 140 switches between active switch 121 and switch 122 to turn on and off, inputting current Ihb into primary winding 161 and charging / discharging capacitor CR. The condition for controller 140 to operate in normal mode M1 is that controller 141 requests energy transfer from primary winding to secondary winding via feedback 175 to maintain the amplitude of output voltage 123, as load 118 consumes the power provided by output voltage 123.

[0101] In certain circumstances, feedback signal 175 indicates operation in a so-called pause mode, in which controller 140 temporarily stops (suspends) energy input to the primary winding 161, such as between time T50 and time T51. The condition for controller 140 to operate in the so-called pause mode M2 ​​is that feedback signal 175 indicates that it is not necessary to transfer energy to the secondary winding to generate output voltage 123.

[0102] Feedback signal 175 indicates an example of operation in pause mode when load 118 stops consuming power supplied by output voltage 123. In this case, during pause mode M2, controller 140 measures the amount of time during which the power converter 100 and the corresponding switches 121 and 122 are controlled in the pause mode between time T50 and time T51. In pause mode M2, the controller continuously deactivates switches 121 and 122. As previously discussed, stopping the activation of the switches prevents energy from flowing from the primary winding 161 to the secondary winding 162.

[0103] Finally, at or near time T51, assuming feedback signal 175 indicates a switch back to normal operating mode M1, as load 118 continues to consume power supplied by the output voltage. However, in this example, before re-entering mode M1, controller 140 operates in mode M3 to discharge the voltage Vcr across resonant capacitor Cr, thereby aligning / synchronizing the voltage. More specifically, in one example, the purpose of operating in mode M3 between time T51 and time T55 before re-entering mode M1 is to ensure that the voltage Vcr across capacitor Cr is synchronized / aligned with the voltage of output voltage 123 across capacitor Cout. This synchronization discussed herein reduces the stress on switches 122 and 121 when switches 121 / 122 are further switched back to normal operating mode M1 at or near time T55 and thereafter.

[0104] In one example, in mode M3, controller 140 pulses switch 122 multiple times or pulses of a duration (while switch 121 is deactivated to the off state). The number of pulses or the duration depends on the duration of a previously measured converter switch pause time (between time T50 and time T51), where the so-called switch pause time corresponds to the situation where feedback 175 indicates a halt to the supply of energy to the primary winding 161.

[0105] In one of the proposed example solutions, as previously discussed, controller 140 can be configured to measure the converter pause time (the duration associated with operation in mode 2) indicated by feedback signal 175 (such as the voltage Vfb input to controller 140), where feedback signal 175 indicates the desired converter operation (i.e., switching to enter and exit the pause mode), and controller 140 initiates the execution of activation and deactivation (pulsed on and off) switch 122 an appropriate number of times in mode M3 (while switch 121 is always off) to discharge capacitor Cr before operating again in normal mode M1.

[0106] like Figure 5B As shown, before resuming normal operation (switching between activation switch 121 and activation switch 122 to transfer energy from the input voltage to the primary and secondary windings), the number of pulses for activation switch 122 in mode M3 depends on the previous pause duration of the converter, measured between time T50 and time T51. Similarly, the pause duration occurs in response to feedback signal 175 instructing controller 140 to stop supplying energy to the primary winding 161.

[0107] Therefore, the controller 140 discussed herein can be configured to measure the pause duration of operation in mode M2, and use this duration information as the basis for controlling how many times the low-side switch 122 is pulsed on and off (in mode M3 between time T51 and time T55) before the power converter 100 resumes operation in normal mode M1 (such as after time T55).

[0108] As discussed previously, normal mode M1 involves load 118 consuming energy supplied by output voltage 123, which is powered by energy received from secondary winding 162. Suppose that load 118 stops consuming energy supplied by output voltage 123 at or near time T50. In this case, controller 141 generates a feedback signal 175 to indicate this so-called pause condition for operation in mode M2. During this pause condition, controller 140 of power converter 100 temporarily deactivates both switches 121 and 122.

[0109] As another example, suppose controller 140 measures that the pause condition during operation in mode M2 ​​lasts for 305 milliseconds (ms). In this case, assuming that the transition from pause time to low-side activation pulse is one pulse every 20 milliseconds during pause time in mode M2, then during mode M3, controller 140 generates 15 pulses applied to switch 122 before operating the power converter again in normal mode (i.e., 305ms sleep / pause => 305 / 20 ~= 15 pulses activating switch 122 to turn on and off, while switch 121 is set to the off state).

[0110] During mode M3, this controlled pulse to the low-side switch 122 causes the energy in capacitor Cr to discharge, thereby generating a current Ihb through the primary winding 161 based on the energy discharge from capacitor Cr. By switching the switch 122 to discharge energy into capacitor Cr during mode M3, the voltage amplitude across the resonant capacitor Cr is reduced and becomes more aligned or synchronized with the amplitude of the output voltage 123.

[0111] As another example, suppose controller 140 measures that the pause condition during operation in mode M2 ​​lasts for 440 milliseconds (ms). In this case, assuming the pause time to pulse conversion is one pulse every 20 milliseconds, then during mode M3, controller 140 generates 22 pulses that are subsequently applied to switch 122 before operating the power converter again in normal mode (i.e., 440ms sleep => 440 / 20 ~= 22 pulses that activate switch 122 to turn it on and off, while switch 121 is set to the off state).

[0112] During mode M3, this controlled pulse to the low-side switch 122 causes the energy in capacitor Cr to discharge, thereby generating a current Ihb through the primary winding 161 based on the energy discharge of voltage Vcr and the corresponding energy stored in capacitor Cr. The energy discharge of capacitor Cr reduces the amplitude of voltage Vcr across resonant capacitor Cr and makes it more aligned with the amplitude of output voltage 123.

[0113] Therefore, as Figure 5A , Figure 5BIn one example shown in other figures herein, the device (such as a resonant power converter, a hybrid flyback converter, etc.) or other suitable entity includes a controller 140. The controller 140 may be configured (also referred to as operable to): control the on / off settings of a plurality of switches 121 / 122 in the resonant power converter 100 during a first operating mode (normal or M1) to convert input voltage 121 to output voltage 123; implement a second operating mode M2 ​​(such as a so-called pause mode) to stop switching the on and off of the plurality of switches in response to a first feedback 175; and control the plurality of switches in the resonant power converter in a third mode M3, based on the duration associated with operation of the resonant power converter in pause mode (M2), to discharge the resonant capacitor Cr of the resonant power converter 100 before resuming operation in normal mode M1.

[0114] As discussed earlier, during the third mode M3, multiple switches 122 / 122 are controlled to discharge the resonant capacitor Cr, including keeping switch 121 in the off state between time T51 and time T55, while switch 122 is pulsed on and off between time T51 and time T55.

[0115] In another example, the duration between time T50 and time T51 is measured by a second operating mode M2 ​​(possibly) controlled by feedback 175, which has been implemented to stop the switching of multiple switches 121 / 122.

[0116] In another example, note again that multiple switches 121 / 122 in the resonant power converter 100 are connected in series; and the controller 140 is also configured to derive a metric (such as a duration value, a control value, etc.) for controlling the switch 122 based on the duration. This metric (such as the control value) can indicate the timing associated with activating the switch 122 to discharge the resonant capacitor Cr of the resonant power converter.

[0117] For example, as discussed earlier, this metric can be generated by controller 140, and can also indicate the number or duration of pulses that activate switch 122 to cause the resonant capacitor to discharge when in temporary mode M3 (resonant capacitor discharge mode). As discussed earlier, the magnitude of the metric used to control switch 122 (controlled duration in mode M3) can be proportional to the magnitude of the measured duration associated with operation in mode M2 ​​between time T50 and time T51.

[0118] Therefore, in one example, controller 140 is configured to control a plurality of switches 121 / 122 in the resonant power converter to discharge the resonant capacitor Cr in response to receiving second feedback (such as feedback 175 during mode M2), wherein the second feedback indicates that the amplitude of output voltage 123 is greater than the setpoint reference voltage. In other words, the second feedback 175 can indicate operation in mode M2 ​​based on the amplitude of output voltage 123 being greater than the setpoint reference voltage 179.

[0119] As discussed earlier, other conditions may also cause the power converter 100 to operate in a pause mode (mode M2). For example, the setpoint reference voltage 179 may be changed from 100 volts to 50 volts. This condition may cause the feedback signal to indicate operation of the primary side of the power converter 100 in pause mode.

[0120] Figure 6 This is an example timing diagram illustrating the implementation of multiple switching pulses to discharge energy stored in a resonant capacitor, as discussed herein.

[0121] As discussed earlier, feedback signal 175 can be configured to indicate operation of the primary side of power converter 108 in a so-called pause mode or quasi-pause mode (such as M4) between time T61 and time T70.

[0122] In this example, during the pause request period between time T61 and time T70, and during operation in the corresponding mode M4 indicated by feedback 175, controller 140 occasionally pulses switch 122 on and off, while switch 121 is set to the off state to ensure that the voltage Vcr across resonant capacitor Cr is aligned / synchronized with the voltage of output voltage 123 across output capacitor Cout.

[0123] Therefore, the technique described herein includes controller 140 periodically generating low-side switching pulses to control switch 122 during a so-called BM sleep mode M4 (pause mode or quasi-pause mode), such as an on-off control signal pulse (LSGD) applied to the gate node of switch 122, to ensure voltage synchronization / alignment of Cr and Cout. In this example, controller 140 detects the start time of the so-called pause mode or sleep mode M4 in response to detecting that feedback signal 175 drops below threshold level TL1 at or near time T61.

[0124] In response to the detection of operation in sleep mode M4 at or near time T61, controller 140 generates an on-off control pulse LSGD (such as similar to...). Figure 2The controller 140 generates an on-off control pulse LSGD applied to the gate node of switch 122, starting at time T62 (such as one or more on-off control pulses) and ending at time T63; the controller 140 generates an on-off control pulse LSGD applied to switch 122, starting at time T64 (such as one or more on-off control pulses) and ending at time T65; the controller 140 generates an on-off control pulse LSGD applied to switch 122, starting at time T66 (such as one or more on-off control pulses) and ending at time T67; the controller 140 generates an on-off control pulse LSGD applied to switch 122, starting at time T68 (such as one or more on-off control pulses) and ending at time T69. At or near time T70, the controller 140 detects that the amplitude of the feedback signal 175 is greater than the threshold level TL2.

[0125] In response to the detection of this condition at time T70, controller 140 switches back to operating power converter 100 in normal operating mode M1, wherein controller 140 repeatedly switches between activating switch 121 and deactivating switch 122 for a first duration, and then between deactivating switch 121 and activating switch 122 for a second duration. This on-off control of switches 121 and 122 in normal mode M1 again causes energy to be transferred from primary winding 161 to secondary winding 162, and control based on feedback 175 maintains the amplitude of output voltage 123 at the desired level.

[0126] In one example, the greater the magnitude of the feedback signal 175 above the threshold level TL2, the longer the total percentage of time, or duty cycle, that the controller 140 will have active during the on-off switching. Therefore, the feedback signal 175 can be configured to indicate the error associated with the output voltage 123 relative to the setpoint reference voltage 179. That is, when the feedback signal 175 indicates that the magnitude of the output voltage 123 is greater than the setpoint reference voltage 179, the feedback signal 175 controls the controller 140 to operate in mode M4 (pause mode or quasi-pause mode). Conversely, when the feedback signal 175 indicates that the magnitude of the output voltage 123 is less than the setpoint reference voltage 179, the feedback signal 175 instructs the controller 140 to operate again in mode M1.

[0127] Therefore, in this example, the device (such as a resonant power converter, a hybrid flyback converter, etc.) or other suitable entity includes a controller. This controller can be configured (also known as operable to): control a plurality of switches 121 and 122 in the resonant power converter 100 during a first operating mode M1 to convert the input voltage Vin to the output voltage 123; implement an operating mode M4 controlling the plurality of switches, including switches 121 and 122, in response to a first feedback 175; and during operating mode M4, control switch 121 to an off state while controlling switch 122 to operate between an off state and an on state to discharge the resonant capacitor Cr of the resonant power converter 100.

[0128] In one example, feedback 175 indicates that the amplitude of the output voltage 123 is greater than a threshold level (feedback signal 175 is less than threshold level TL1). Controller 140 can also be configured to, after operating mode M4 between time T61 and time T70, in response to receiving feedback signal 175 at time T70 that is greater than threshold level TL2 (indicating that the output voltage 123 is less than a threshold level (such as a setpoint reference voltage)), resume operation of the resonant power converter in operating mode M1. In this case, in response to transitioning to a wake-up state and the corresponding operating mode M1, controller 140 is configured to switch the operation of the resonant power converter 100 from operating mode M4 to operating mode M1.

[0129] In another example, controller 140 may be configured to switch the operation of resonant power converter 100 from operation mode M4 to operation mode M1 in response to detecting that the amplitude of output voltage 123 is less than the setpoint reference voltage 179, which is indicated by the amplitude of feedback signal 175 being greater than the threshold level TL2.

[0130] In another example, the operation of the resonant power converter 100 in operating mode M4 between time T61 and time T70 advantageously maintains the magnitude of the voltage Vcr across the resonant capacitor Cr with respect to the output voltage 123.

[0131] In another example, controller 140 can be configured to resume operating mode M1, which switches multiple switches between on / off states to convert input voltage to output voltage, after operating mode M4 between time T61 and time T70.

[0132] As discussed previously, multiple switches associated with power converter 100 can be configured as switches 121 and 122, which are arranged in a first series circuit path, wherein the first series circuit path is configured to control the transmission of current Ihb through the primary winding 161 of transformer T1. In a second series circuit path, the primary winding 161 is arranged in series with a resonant capacitor Cr. The second series circuit path (such as the capacitor Cr in the primary winding 161) is arranged in parallel with switch 122. The current Ihb through the primary winding 161 results in a corresponding current Isec through the secondary winding 162, wherein the current through the secondary winding generates an output voltage 123 to power load 118.

[0133] Figure 7 This is an example circuit diagram illustrating a supplementary resistor used to monitor the amplitude of the current through the resonant capacitor and windings, as discussed earlier.

[0134] In this example, the power converter 100 includes a resistor R2 disposed between the source node (node ​​N2) and node N1 of switch 122. In this case, controller 140 monitors the magnitude of the voltage at node N2 (the voltage across resistor R2), which indicates the magnitude of the current Ihb through the primary winding 161 and capacitor Cr. For example, the magnitude of current Ihb is measured based on the voltage at node N2 (the voltage across resistor R2) divided by the resistance associated with resistor R2.

[0135] Figure 8 This is an example diagram illustrating the implementation of multiple switching pulses to discharge energy stored in a resonant capacitor, as discussed in this article.

[0136] In this example, using such Figure 7 The circuit shown operates the power converter 100 and its corresponding switches 121 and 122 in mode M1 before time T81, as previously discussed. In response to detecting that the feedback signal 175 has dropped below the threshold level TL1, the controller 140 switches to mode M2, where it deactivates both switches 121 and 122 between time T81 and time T83.

[0137] Controller 140 continues to monitor feedback signal 175 between times T81 and T83. At time T83, controller 140 detects that feedback signal 175 is greater than threshold level TL2. In this case, controller 140 again transitions control of switches 121 and 122 in power converter 100 according to normal operating mode M1. In order to synchronize / align the amplitude of voltage Vcr across resonant capacitor Cr with the amplitude of output voltage 123 before re-implementing normal operating mode M1, controller 140 implements operating mode M5. Figure 8As shown, implementing operation mode M5 includes the controller deactivating switch 121 for the entire duration between time T81 and time T91.

[0138] During mode M5, which begins at time T83, controller 140 applies one or more switching control pulses to the gate node of switch 122, starting at or near time T83 and continuing until near time T84. An example of the switching operation is again as follows... Figure 2 As shown. Starting at or near time T83 and continuing until near time T84, one or more control pulses are applied to switch 122, causing the amplitude of the current iLS through resistor R2 and the corresponding switch 122 to rise and exceed the current threshold level TL5. Because the amplitude of the current iLS through resistor R2 and the corresponding switch 122 is greater than the threshold level TL5 at or near time T84, controller 140 continues to operate in mode M5.

[0139] Between time T84 and T85, controller 140 controls both switches 121 and 122 to be in the off state.

[0140] Beginning at time T85, controller 140 applies one or more switching control pulses to the gate node of switch 122 from time T85 to near time T86. These control pulses cause the amplitude of the current iLS through resistor R2 and the corresponding switch 122 to rise above the current threshold level TL5. Because the amplitude of the current iLS through resistor R2 and the corresponding switch 122 is greater than the threshold level TL5 at or near time T86, controller 140 continues to operate in mode M5.

[0141] Between time T86 and T87, controller 140 controls both switches 121 and 122 to be in the off state.

[0142] Beginning at time T87, controller 140 applies one or more switching control pulses to the gate node of switch 122 from time T87 to near time T88. These control pulses, applied from time T87 to near time T88, cause the peak amplitude of the current iLS through resistor R2 and the corresponding switch 122 to rise and exceed the current threshold level TL5. Because the amplitude of the current iLS through resistor R2 and the corresponding switch 122 is greater than the threshold level TL5 at or near time T88, controller 140 continues to operate in mode M5.

[0143] Between time T88 and T89, controller 140 controls both switches 121 and 122 to be in the off state.

[0144] Beginning at time T89, controller 140 applies one or more switching control pulses to the gate node of switch 122 from time T89 or near time T90 until near time T90. These one or more control pulses cause the peak amplitude of the current iLS through resistor R2 and the corresponding switch 122 to rise only below the current threshold level TL5. Because the amplitude of the current iLS through resistor R2 and the corresponding switch 122 is less than the threshold level TL5 at or near time T90, controller 140 switches from mode M5 to mode M1 operation at or near time T90 or at or near time T91. Therefore, at or near time T90, in response to the controller 140 detecting that the peak amplitude of voltage 711 is less than the threshold level TL5 at time T89, the controller 140 detects that capacitor Cr has been fully discharged to below the threshold level, so that the voltage across capacitor Cr is aligned / synchronized with the output voltage 123, thereby enabling the normal operation mode M1 to be restored at some time after time T89.

[0145] Therefore, examples in this paper include the following: when switching back from mode M2 ​​to mode M1, the controller 140 operates in mode M5, during which the controller 140 pulses switch 122 on and off (while switch 121 is set to the off state) whenever the peak amplitude of the current Ihb observed by monitoring the voltage 711 across resistor R2 is higher than a given current threshold TL5.

[0146] Therefore, in this example, the device (such as a resonant power converter, a hybrid flyback converter, etc.) or other suitable entity includes a controller. This controller can be configured to: control multiple switches in the resonant power converter to switch between on / off states during a first operating mode M1 to convert the input voltage to the output voltage 123; and implement a second operating mode M2 ​​in response to a first feedback 175 to stop the on / off switching of the multiple switches; and control the switches 122 of the multiple switches to discharge the voltage Vcr across the resonant capacitor Cr of the resonant power converter based on the magnitude of the current flowing through the switches 122.

[0147] As discussed above, switch 122 can be placed in a series circuit loop; the series circuit loop can be configured to include a combination of switch 122, primary winding 161 of transformer T1 and resonant capacitor Cr.

[0148] In another example, as previously discussed, controller 140 can be configured to control switch 122 to discharge resonant capacitor Cr after implementing operating mode M2 ​​and before resuming operating mode M1, which switches multiple switches between on / off states.

[0149] Furthermore, as discussed above, the examples herein include a controller configured to: when switch 121 of a plurality of switches is deactivated to the off state: monitor the magnitude of the current Ihb through switch 122; compare the magnitude of the current Ihb with a current threshold level TL5; and switch switch 121 between an on state and an off state until the magnitude of the peak current Ihb through switch 121 drops below the current threshold level TL5. Controller 140 may be configured to, in response to detecting that the magnitude of the peak current Ihb exceeds (e.g., drops below) the current threshold level TL5, resume a first operating mode M1 for switching the plurality of switches on and off.

[0150] Another example of this document includes a controller configured to, in response to receiving a second feedback signal 175 indicating that the amplitude of the output voltage 123 has dropped below a voltage threshold level (the amplitude of the feedback signal is greater than the threshold level TL2), control a switch 122 of a plurality of switches to discharge a resonant capacitor Cr in order to transition from mode M2 ​​to mode M1 (operating in mode M5 in between).

[0151] Furthermore, as discussed earlier, the amplitude of the monitored current Ihb can be the peak amplitude of the current Ihb through switch 122.

[0152] In another example, the magnitude of the current Ihb can be measured based on the voltage across a resistor R2 connected in series with the resonant capacitor Cr, where the voltage across the capacitor Cr is proportional to the magnitude of the current Ihb.

[0153] Figure 9 This is an example diagram illustrating an implementation of the resonant power converter discussed herein.

[0154] As discussed above, the power converter 100 discussed herein can be implemented in any suitable manner.

[0155] In one example, the resonant circuit formed by the primary winding 161 and the capacitor Cr can be implemented as a circuit device including switch 121, instead of switch 122 as previously discussed. Therefore, the resonant circuit formed by the transformer T1 and the resonant capacitor Cr can be connected to the input voltage Vin, where the operations of switches 121 and 122 are opposite.

[0156] Figure 10This is an example diagram illustrating a first method for discharging energy stored in a resonant capacitor using multiple switching pulses, as discussed herein.

[0157] In the processing operation 1010 of flowchart 1000, the controller controls the on / off settings of multiple switches in the resonant power converter during the first operating mode to convert the input voltage into the output voltage.

[0158] In processing operation 1020, in response to the first feedback, the controller implements a second operating mode to stop switching multiple switches on and off.

[0159] In processing operation 1030, based on the duration associated with the operation of the resonant power converter in the second operating mode, the controller controls multiple switches in the resonant power converter to discharge the resonant capacitor of the resonant power converter.

[0160] Figure 11 This is an example diagram illustrating a second method, as discussed herein, for discharging energy stored in a resonant capacitor by applying multiple switching pulses.

[0161] In the processing operation 1110 of flowchart 1100, the controller controls multiple switches in the resonant power converter during the first operating mode to convert the input voltage into the output voltage.

[0162] In processing operation 1120, in response to a first feedback indicating to stop the execution of the resonant power converter in a first operating mode, the controller implements a second operating mode that controls a plurality of switches, including a first switch and a second switch.

[0163] In processing operation 1130, during the second operating mode, the controller controls the second switch to the off state while controlling the first switch to operate between the off state and the on state to discharge the resonant capacitor of the resonant power converter.

[0164] Figure 12 This is an example diagram illustrating a third method, as discussed herein, for discharging energy stored in a resonant capacitor by applying multiple switching pulses.

[0165] In processing operation 1210 of flowchart 1200, the controller controls multiple switches in the resonant power converter between on / off states during the first operating mode to convert the input voltage into the output voltage.

[0166] In processing operation 1220, in response to the first feedback, the controller implements a second operating mode to stop switching multiple switches on and off.

[0167] In processing operation 1230, based on the amplitude of the current through the first switch of the multiple switches, the controller controls the first switch of the multiple switches to discharge the resonant capacitor of the resonant power converter.

[0168] Again, it should be noted that the techniques described in this paper are well-suited for applications such as power converters, which implement resonant capacitors to support the conversion of input voltage to output voltage. However, it should be understood that the techniques described are not limited to such applications, and are also applicable to other applications.

[0169] Although the invention has been specifically shown and described with reference to its preferred examples, those skilled in the art will understand that various modifications in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Such modifications are intended to be covered by the scope of the invention. Therefore, the foregoing description of examples of the invention is not intended to be limiting. Rather, any limitation on the invention is presented in the following claims.

Claims

1. An apparatus comprising: The controller is operable to: During the first operating mode, the on / off settings of multiple switches in the resonant power converter are controlled to convert the input voltage into the output voltage; In response to the first feedback, a second operating mode is implemented to stop switching the plurality of switches on and off. as well as Based on the duration associated with the operation of the resonant power converter in the second operating mode, the plurality of switches in the resonant power converter are controlled to discharge the resonant capacitor of the resonant power converter.

2. The apparatus of claim 1, wherein the duration is a measurement of the second operating mode implemented when switching of the plurality of switches is stopped.

3. The apparatus of claim 1, wherein the plurality of switches in the resonant power converter comprises a first switch and a second switch connected in series; and The controller is also operable to derive a metric for controlling the first switch based on the duration.

4. The apparatus of claim 3, wherein the magnitude of the metric used to control the first switch is proportional to the magnitude of the duration.

5. The apparatus of claim 3, wherein the metric indicates the number of pulses that activate the first switch to cause the discharge of the resonant capacitor.

6. The apparatus of claim 3, wherein the metric indicates a timing attribute associated with activating the first switch to discharge the resonant capacitor of the resonant power converter.

7. The apparatus of claim 1, wherein the plurality of switches includes a first switch and a second switch, the first switch being connected in series with the resonant capacitor; and The controller is also operable to: during the discharge of the resonant capacitor, when the second switch is controlled to be off, control the switching operation of the first switch to discharge the resonant capacitor before controlling the power converter again in the first operating mode, based on the duration.

8. The apparatus of claim 1, wherein the controller is further operable to: When in the second operating mode, measure the duration during which switching of the plurality of switches is stopped; Based on the measured duration, the timing of activation and deactivation of the first switch of the plurality of switches is controlled to discharge the resonant capacitor in the second operating mode; and The cumulative on-time associated with the controlled timing of the first switch used to discharge the resonant capacitor is based on the measured duration.

9. The apparatus of claim 1, wherein the plurality of switches includes a first switch and a second switch disposed in a first series circuit path, the first series circuit path of the plurality of switches being operable to control the transfer of current received from the input voltage to the resonant capacitor; The resonant power converter further includes a primary winding connected in series with the resonant capacitor in the second series circuit path; The second series circuit path is connected in parallel with the second switch; and The primary winding is magnetically coupled to a secondary winding that is operable to generate the output voltage.

10. The apparatus of claim 1, wherein the controller is further operable to: In response to receiving a second feedback, the plurality of switches in the resonant power converter are controlled to discharge the resonant capacitor, wherein the second feedback indicates that the amplitude of the output voltage is less than the setpoint reference voltage.

11. An apparatus comprising: The controller is operable to: During the first operating mode, multiple switches in the resonant power converter are controlled to convert the input voltage into the output voltage; In response to a first feedback indicating that the resonant power converter should be stopped in a first operating mode, a second operating mode is implemented to control the plurality of switches, including a first switch and a second switch. and During the second operating mode, the second switch is controlled to the off state, while the operation of the first switch is controlled between the off state and the on state, so as to discharge the resonant capacitor of the resonant power converter.

12. The apparatus of claim 11, wherein the first feedback indicates that the amplitude of the output voltage is greater than a threshold level; and The second operating mode is the pause mode.

13. The apparatus of claim 12, wherein the controller is further operable to: after the second operating mode, in response to receiving second feedback, resume operation of the resonant power converter in the first operating mode.

14. The apparatus of claim 13, wherein the second feedback indicates that the output voltage is less than a threshold level.

15. The apparatus of claim 11, wherein the operation of the resonant power converter in the second operating mode is operable to maintain the amplitude of a first voltage across the resonant capacitor with respect to the amplitude of the output voltage.

16. The apparatus of claim 11, wherein the controller is operable to: after the second operating mode, resume the first operating mode of switching the plurality of switches between the on / off states to convert the input voltage into the output voltage.

17. The apparatus of claim 11, wherein the plurality of switches includes the first switch and the second switch disposed in a first series circuit path, the first series circuit path being operable to control the transmission of current received from an input voltage; The resonant power converter further includes a primary winding connected in series with the resonant capacitor in the second series circuit path; The second series circuit path is connected in parallel with the second switch; and The primary winding is magnetically coupled to a secondary winding that is operable to generate the output voltage.

18. An apparatus comprising: The controller is operable to: During the first operating mode, multiple switches in the resonant power converter are controlled between on / off states to convert the input voltage into the output voltage; In response to the first feedback, a second operating mode is implemented to stop switching the plurality of switches on and off; and Based on the amplitude of the current passing through the first switch of the plurality of switches, the first switch of the plurality of switches is controlled to discharge the resonant capacitor of the resonant power converter.

19. The apparatus of claim 18, wherein the first switch is disposed in a series circuit loop; and The series circuit loop includes a combination of the first switch, the primary winding of the transformer, and the resonant capacitor.

20. The apparatus of claim 18, wherein the controller is operable to control the first switch to discharge the resonant capacitor after the second operating mode and before resuming the first operating mode that switches the plurality of switches between the on / off states.

21. The apparatus of claim 18, wherein the plurality of switches includes a second switch, and the first switch and the second switch are connected in series; and The control of the first switch used to discharge the resonant capacitor is implemented by the controller in a third operating mode, which includes: Before switching back to execute the resonant power converter in the first operating mode, the second switch is deactivated to the off state, while the first switch is switched between the on and off states.

22. The apparatus of claim 18, wherein the controller is further operable to: In the third operating mode where the resonant capacitor is discharged based on the amplitude of the current, when the second switch of the plurality of switches is deactivated to the off state: Monitor the amplitude of the current passing through the first switch; The amplitude of the current is compared with a current threshold level; and The first switch is switched between an on state and an off state until the magnitude of the current through the first switch drops below the current threshold level.

23. The apparatus of claim 22, wherein the controller is further operable to: In response to detecting that the magnitude of the current exceeds the current threshold level, the first operating mode of switching the plurality of switches on and off is restored.

24. The apparatus of claim 18, wherein the controller is further operable to: In response to receiving a second feedback indicating that the amplitude of the output voltage has dropped below a voltage threshold level, the first switch of the plurality of switches is controlled to discharge the resonant capacitor.

25. The apparatus of claim 18, wherein the plurality of switches includes a first switch and a second switch disposed in a first series circuit path, the first series circuit path being operable to control the transmission of current received from an input voltage. The resonant power converter further includes a primary winding connected in series with the resonant capacitor in the second series circuit path; The second series circuit path is connected in parallel with the second switch; and The primary winding is magnetically coupled to a secondary winding that is operable to generate the output voltage.

26. The apparatus of claim 18, wherein the amplitude of the current is the peak amplitude of the current through the first switch.

27. The apparatus of claim 18, wherein the amplitude of the current is measured based on the voltage across a resistor connected in series with the resonant capacitor, the voltage being proportional to the amplitude of the current.

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