Parallel connected power converters using push-pull feedback networks

Abstract

Parallel connected power converters using push-pull feedback networks are described herein. The power converter may be a switched-mode (switched) power converter (SMPS) controlled by a load-dependent signal such that the switching frequency increases as a function of the load. A load-dependent signal (i.e., a controller signal) may drive the push-pull feedback network to adjust the voltage regulation feedback signal and equalize the output current (i.e., output power) from the power converters connected in parallel.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 511,287, filed on June 30, 2023, which is hereby incorporated by reference in its entirety.

[0003] Background Information Technical Field

[0004] The present invention relates to parallel connected power converters, and more particularly to parallel connected flyback converters using a push-pull feedback network. Background Art

[0005] Many electronic devices, such as cell phones, laptop computers, etc., are powered by direct current (dc) power from a power supply. Conventional wall sockets typically deliver high voltage alternating current (ac) power that needs to be converted into regulated dc power to be used as a power source for consumer electronic devices. Switching mode power converters, also known as switching mode power supplies (SMPS), are commonly used due to their high efficiency, small size, and light weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Non-limiting and non-exhaustive embodiments of parallel-connected power converters using a push-pull feedback network are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0007] Figure 1 A system of parallel-connected power converters using a push-pull feedback network according to an embodiment is illustrated.

[0008] Figure 2 A system of parallel-connected power converters using a push-pull feedback network according to an embodiment is illustrated.

[0009] Figure 3A A push-pull feedback network according to the teachings herein is illustrated.

[0010] Figure 3B A push-pull feedback network according to the teachings herein is illustrated.

[0011] Figure 4 A system of parallel-connected power converters using a push-pull feedback network according to an embodiment is illustrated.

[0012] Figure 5A conceptual flow chart for providing total power with a regulated output voltage to a load according to an embodiment is illustrated.

[0013] Figure 6 A system of parallel-connected power converters using a push-pull feedback network according to another embodiment is illustrated.

[0014] In all several views of the accompanying drawings, corresponding reference characters indicate corresponding parts. It will be appreciated by the technician that the elements in the accompanying drawings are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the sizes of some elements in the accompanying drawings may be exaggerated relative to other elements to help improve the understanding of the various embodiments of the teachings of this article. In addition, common but easily understood elements that are useful or necessary in commercially feasible embodiments are generally not depicted so as to less hinder the viewing of these various embodiments of power converters connected in parallel using push-pull feedback networks. DETAILED DESCRIPTION

[0015] In the following description, many specific details are set forth to provide a thorough understanding of the parallel-connected power converter using a push-pull feedback network. However, it is apparent to one of ordinary skill in the art that specific details need not be employed to practice the teachings herein. In other cases, well-known materials or methods are not described in detail to avoid obscuring the present disclosure.

[0016] References throughout this specification to "one embodiment", "anembodiment", "one example" or "an example" mean that the specific features, structures or characteristics described in conjunction with the embodiment or example are included in at least one embodiment of the (multi-output) switch-mode power converter system. Therefore, the phrases "in one embodiment", "in an embodiment", "one example" or "an example" appearing in various places throughout this specification do not necessarily all refer to the same embodiment or example. In addition, specific features, structures or characteristics may be combined in any suitable combination and / or sub-combination in one or more embodiments or examples. Specific features, structures or characteristics may be included in an integrated circuit, an electronic circuit, a logic circuit or other suitable components that provide the described functions. In addition, it should be understood that the drawings provided herewith are used for the purpose of explanation to ordinary technicians in the field, and the drawings are not necessarily drawn to scale.

[0017] In the context of the present application, when a transistor is in an "off state" or "disconnected", the transistor blocks current and / or substantially does not conduct current. In contrast, when a transistor is in an "on state" or "conducting", the transistor is capable of significantly conducting current. By way of example, in one embodiment, a high voltage transistor comprises an N-channel metal oxide semiconductor (NMOS) field effect transistor (FET), wherein a high voltage is supported between a first terminal, i.e., a drain, and a second terminal, i.e., a source. In some embodiments, an integrated controller circuit may be used to drive a power switch when regulating the energy provided to a load. In addition, for the purposes of the present disclosure, "ground" or "ground potential" refers to a reference voltage or potential, relative to which all other voltages or potentials of an electronic circuit or integrated circuit (IC) are defined or measured. In addition, according to power electronics theory (i.e., power is related to the rate of change of energy), "power" transfer may be implied by "energy" transfer; conversely, "energy" transfer may be implied by "power" transfer.

[0018] Typically, a power converter (ie, power supply) is specified and / or rated to provide a maximum output power at a specified output voltage. Such a rating or specification limits the maximum current that the power converter can deliver to the load.

[0019] However, problems arise in applications where the output power and corresponding load current exceed the maximum output power rating of the power converter; therefore, a way needs to be found to increase the available output power beyond the specified maximum of the power converter. In theory, connecting power converters in parallel can facilitate a load sharing solution.

[0020] Unfortunately, in practice, power converters may not be easily connected in parallel due to practical and design-related limitations. Typically, power converters are not designed to be connected in parallel, and circuit systems used to improve performance may interfere with the parallel load sharing configuration. Therefore, it is necessary to find a load sharing solution for connecting power converters in parallel.

[0021] This article describes parallel-connected power converters using a push-pull feedback network. The power converter can be a switch mode (switching) power converter (SMPS) that is controlled by a load-dependent signal so that the switching frequency increases as a function of the load. The load-dependent signal (i.e., the controller signal) can drive the push-pull feedback network to adjust the voltage regulation feedback signal and balance the output current (i.e., output power) from the parallel-connected power converters.

[0022] Figure 1A system 50 of parallel-connected power converters 100a-100b using push-pull feedback networks 140a-140b is illustrated according to one embodiment. The power converter 100a receives a rectified supply voltage V at terminal 101a. IN1 The power converter 100b receives input power, the rectified supply voltage is measured relative to ground GND at terminal 103a. The power converter 100b receives input power from the rectified supply voltage V at terminal 101b. IN2 Receiving input power, the rectified supply voltage is measured with respect to ground GND at terminal 103b.

[0023] although Figure 1 The embodiment of the power converter 100a-100b is illustrated as a power converter 100a-100b that is powered from two rectified supply voltages V IN1 、V IN2 Receive input power, but other configurations are possible. For example, without departing from the scope of the present disclosure, the power converters 100a-100b can be powered from a single rectified supply voltage (e.g., supply voltage V IN1 ) receives input power.

[0024] The load 142 is connected to the output node NV O and secondary ground, and requires a regulated output voltage V O and load (output) current I L The power converter 100a and the power converter 100b are connected in parallel at the output node NV O In this way, the power converter 100a and the power converter 100b can share the load (ie, the total load current I L ).

[0025] As illustrated, the power converter 100a provides an output current I L1 , and the power converter 100b provides an output current I to the load L2 According to circuit theory, the total load current I L Can be equal to the output current I L1 ,I L2 The sum of the output voltages V O Multiply by the load current I L ).

[0026] As also illustrated, power converter 100a and power converter 100b have a flyback configuration. Power converter 100a includes energy transfer element 102a (e.g., a transformer), secondary diode D1, controller circuit 107a, and primary switch 152a. Energy transfer element 102a includes primary winding 112a and secondary winding 99a. Primary switch 152a is electrically coupled to primary winding 112a; energy (i.e., power) can be transferred to secondary winding 99a according to the switching cycle of primary switch 152a.

[0027] For example, the controller circuit 107a may provide a gate signal (gate signal, strobe signal) V CS1 , to turn on and off the primary switch 152a. According to the switch mode power supply (SMPS) theory, the gate signal V CS1 can be transformed (i.e., can be changed) according to the switching waveform 191a; thus, the primary current I sw1 The primary winding 112a is excited according to the switching waveform 192a. As illustrated, the two switching waveforms 191a-192a are driven according to the period T SW1 The switch cycle is switched on and off.

[0028] In addition, according to SMPS theory, the controller circuit 107a can adjust the switching cycle (ie, the period T SW1 ), so that the power is regulated at the output voltage V O is delivered to the load 142. For example, when the load demand increases, the feedback signal FB1 may decrease; and in response, the controller circuit 107a may increase and / or adjust the gate signal V CS1 frequency.

[0029] Similarly, power converter 100b includes energy transfer element 102b (e.g., transformer), secondary diode D2, controller circuit 107b, and primary switch 152b. Energy transfer element 102b includes primary winding 112b and secondary winding 99b. Primary switch 152b is electrically coupled to primary winding 112b; energy (i.e., power) can be transferred to secondary winding 99b according to the switching cycle of primary switch 152b.

[0030] For example, the controller circuit 107b can provide a gate signal V CS2 , to turn on and off the primary switch 152b. According to the switch mode power supply (SMPS) theory, the gate signal V CS2 can be transformed (i.e., can be changed) according to the switching waveform 191b; thus, the primary current I sw2 The primary winding 112b is excited according to the switching waveform 192b. As illustrated, the two switching waveforms 191b-192b are driven according to the period TSW2 The switch cycle is switched on and off.

[0031] In addition, according to SMPS theory, the controller circuit 107b can adjust the switching cycle (ie, the period T SW2 ), so that the power is regulated at the output voltage V O is delivered to the load 142. For example, when the load demand increases, the feedback signal FB2 may decrease; and in response, the controller circuit 107b may increase and / or adjust the gate signal V CS2 frequency.

[0032] According to the teachings herein, power converter 100a may include a push-pull feedback network 140a, and power converter 100b may include a push-pull feedback network 140b. As illustrated, push-pull feedback network 140a and push-pull feedback network 140b may receive a control signal V from controller circuit 107a. CR1 , and receives a control signal V from the controller circuit 107b CR2 . Control signal V CR1 and V CR2 can vary with load demand (i.e., load current Io). For example, the control signal V CR1 According to the period T SW1 The switching waveform 193a changes; and as with the period T SW1 The corresponding switching frequency related to the inverse of can be a monotonically increasing function of the load demand. Similarly, the control signal V CR2 According to the period T SW2 The switching waveform 193b changes; and as with the period T SW2 The corresponding switching frequency related to the inverse of can be a monotonically increasing function with respect to the load demand.

[0033] Figure 2 A system 50 of parallel-connected power converters 100a-100b using push-pull feedback networks 140a-140b is illustrated according to one embodiment. In addition to the power converters 100a-100b illustrated with additional and / or alternative components, Figure 2 Implementation plan and Figure 1 The implementation scheme is similar.

[0034] The power converter 100a includes a primary clamp 110a, an output capacitor C1, a primary current sensing element 54a, and a resistor R W1 In addition, an N-type field effect transistor (NFET) 126a replaces the diode D1 and can operate as a synchronous rectifier (SR). Therefore, the NFET 126a may also be referred to as a synchronous rectifier 126a without departing from the scope of the present disclosure.

[0035] The controller circuit 107a includes a secondary controller 108a and a primary controller 109a. The primary controller 109a is referenced to the ground GND and can receive a current sensing signal SENS1 from the primary current sensing element 54a. In one application, when the primary current I sw1 When the current limit (eg, ten amps) is exceeded, primary controller 109a may turn off primary switch 152a. Alternatively, and additionally, primary controller 109a may turn on primary switch 152a in response to request signal FL1 from secondary controller 108a.

[0036] The secondary controller 108a is referenced to the secondary ground RTN. As illustrated, the secondary controller 108a is connected to the secondary ground RTN via a resistor R W1 Receives forward signal FW1 from forward node 123a. In addition, secondary controller 108a can provide control signal V CR1 And receive the feedback signal FB1. In response to the feedback signal FB1, when there is a need for a larger output current I L1 When required, the secondary controller may send a request signal FL1 to the primary controller 109a.

[0037] Similarly, power converter 100b includes primary clamp 110b, output capacitor C2, primary current sensing element 54b, and resistor R W2 In addition, an N-type field effect transistor (NFET) 126 b replaces the diode D2 and can operate as a synchronous rectifier (SR). Therefore, without departing from the scope of the present disclosure, the NFET 126 b may also be referred to as a synchronous rectifier 126 b.

[0038] The controller circuit 107b includes a secondary controller 108b and a primary controller 109b. The primary controller 109b is referenced to the ground GND and can receive a current sensing signal SENS2 from the primary current sensing element 54b. In one application, when the primary current I SW2 When the current limit (eg, ten amps) is exceeded, primary controller 109b may turn off primary switch 152b. Alternatively, and additionally, primary controller 109b may turn on primary switch 152b in response to request signal FL2 from secondary controller 108a.

[0039] The secondary controller 108b is referenced to the secondary ground RTN. As illustrated, the secondary controller 108b is connected to the secondary ground RTN via a resistor R W2 Receives forward signal FW2 from forward node 123b. In addition, secondary controller 108b can provide control signal V CR2And receive feedback signal FB2. In response to feedback signal FB2, when there is a need for a larger output current I L2 When required, the secondary controller may send a request signal FL2 to the primary controller 109b.

[0040] Furthermore, the power converters 100a-100b may be of the same type and have matching components and / or similar configurations. For example, the primary clamps 110a-110b, the output capacitors C1-C2, the primary current sensing elements 54a-54b, and / or the resistors R W1 -R W2 May have the same values ​​and / or characteristics. Alternatively, and in addition, the controller circuits 107a-107b may be of the same type and have matching and / or similar configurations. For example, the controller circuit 107a may be of the same type as the controller circuit 107b and have the same data table as the controller circuit 107b.

[0041] According to the teachings herein, the push-pull feedback network 140a-140b may receive a control signal V CR1 、V CR2 . Control signal V CR1 The switching frequency can be related to the output current I L1 The output power is a monotonically increasing function of the control signal V CR2 The switching frequency can be related to the output current I L2 The associated output power is a monotonically increasing function.

[0042] As follows about Figure 3A and Figure 3B As discussed, due to the control signal V CR1 、V CR2 The functional dependence of the control signal V on the frequency CR1 、V CR2 Push-pull feedback can be generated, whereby the feedback signals FB1 and FB2 become about V CR1 The frequency and V CR2 In addition, according to the teachings of this article, in response to the control signal V CR1 、V CR2 The push-pull feedback networks 140a and 140b can provide feedback signals FB1 and FB2, so that the load current Io is proportional to the output current I L1 and output current I L2 Divide equally.

[0043] Figure 3A 1 illustrates a push-pull feedback network 140a according to the teachings herein. The push-pull feedback network 140a includes a voltage divider resistor R A1 , voltage divider resistor R B1, auxiliary resistor R X1 , path resistor R SR1 , path resistor R SN1 , diode DP1, capacitor CP1 and NFET MN1. Resistor R A1 Electrically coupled at the output node NV O and feedback node NFB1; and resistor R B1 is electrically coupled between the feedback node NFB1 and the return ground RTN. Thus, the feedback signal FB1 may at least partially depend on the voltage divider resistor R A1 , R B1 and output voltage V O .

[0044] As shown, the auxiliary resistor R X1 is electrically coupled between the node NP1 and the feedback node NFB1, and the capacitor CP1 is electrically coupled between the node NP1 and the secondary ground RTN. SR1 is electrically coupled between node NP1 and the cathode of diode DP1; and path resistor R SN1 Electrically coupled between the node NP1 and the drain of the NFET MN1.

[0045] In addition, as illustrated, the anode of the diode DP1 receives the control signal V CR1 Therefore, the feedback signal FB1 may also at least partially depend on the control signal V CR1 And the auxiliary resistor R X1 , path resistor R SR1 and capacitor CP1. In addition, the feedback signal FB1 may be at least partially dependent on the control signal V CR1 The switching frequency and amplitude of (e.g., switching waveform 193a).

[0046] As illustrated, the source of NFET MN1 is electrically coupled to the secondary ground RTN, and the gate of NFET MN1 receives the control signal V CR2 In this way, when the control signal V CR2 When NFET MN1 is made conductive, NFET MN1 may pull node NP1 to the secondary ground RTN. Therefore, feedback signal FB1 may also depend at least in part on path resistor R SN1 , control signal V CR2 The switching frequency and amplitude of (e.g., switching waveform 193b).

[0047] According to the teaching of this article, the feedback signal FB1 has an influence on the control signal V CR1 and V CR2 The dependence of the output current I L1 is adjusted to be roughly equal to the output current IL2 Therefore, the control signal V CR1 and V CR2 The power delivered by power converter 100a may be regulated to be substantially equal to the power delivered by power converter 100b.

[0048] Figure 3B 1 illustrates a push-pull feedback network 140b according to the teachings herein. The push-pull feedback network 140b includes a voltage divider resistor R A2 , voltage divider resistor R B2 , auxiliary resistor R X2 , path resistor R SR2 , path resistor R SN2 , diode DP2, capacitor CP2 and NFET MN2. Resistor R A2 Electrically coupled at the output node NV O and feedback node NFB2; and resistor R B2 is electrically coupled between the feedback node NFB2 and the return ground RTN. Thus, the feedback signal FB2 may at least partially depend on the voltage divider resistor R A2 , R B2 and output voltage V O .

[0049] As shown, the auxiliary resistor R X2 is electrically coupled between the node NP2 and the feedback node NFB2, and the capacitor CP2 is electrically coupled between the node NP2 and the secondary ground RTN. SR2 is electrically coupled between node NP2 and the cathode of diode DP2; and path resistor R SN2 Electrically coupled between the node NP2 and the drain of the NFET MN2.

[0050] In addition, as illustrated, the anode of diode DP2 receives the control signal V CR2 Therefore, the feedback signal FB2 may also be at least partially dependent on the control signal V CR2 and auxiliary resistor R X2 , path resistor R SR2 and the voltage of capacitor CP2. In addition, the feedback signal FB2 may at least partially depend on the control signal V CR2 The switching frequency and amplitude of (e.g., switching waveform 193b).

[0051] As illustrated, the source of NFET MN2 is electrically coupled to the secondary ground RTN, and the gate of NFET MN2 receives the control signal V CR1 In this way, when the control signal V CR1When NFET MN2 is made conductive, NFET MN2 can pull node NP2 to the secondary ground RTN. Therefore, the feedback signal FB2 can also depend at least in part on the path resistor R SN2 , control signal V CR1 The switching frequency and amplitude of (e.g., switching waveform 193a).

[0052] According to the teaching of this article, the feedback signal FB1 has an influence on the control signal V CR1 and V CR2 The dependence of the output current I L2 is adjusted to be roughly equal to the output current I L1 Therefore, the control signal V CR1 and V CR2 The power delivered by power converter 100b may be regulated to be substantially equal to the power delivered by power converter 100a.

[0053] Figure 4 A system 50 of parallel-connected power converters 100a-100b using push-pull feedback networks 140a-140b is illustrated according to one embodiment. In addition to the power converters 100a-100b being drawn to provide a less obstructed view of the push-pull feedback networks 140a-140b, Figure 4 Implementation plan and Figure 2 The implementation scheme is similar.

[0054] As illustrated, the feedback network 140a may receive the output voltage V O , control signal V CR1 and control signal V CR2 , and can provide a feedback signal FB1. Therefore, according to circuit theory, the feedback signal FB1 can depend on the output voltage V O , control signal V CR1 and control signal V CR2 . The control signal V CR1 、V CR2 The DC analysis of the case where the feedback signal FB1 is set to the secondary ground potential makes the output voltage V O Related As About the Voltage Divider Resistor R A1 , R B1 A function of the partial pressure ration.

[0055] According to the teachings of this article, since the control signal V CR1 、V CR2 AC switching behavior, control signal V CR1 、V CR2The feedback signal FB1 can be adjusted so that the output power of the power converter 100a and the corresponding output current (ie, the output current I L1 ) can be related to the output power of the power converter 100b and the corresponding output current (ie, the output current I L2 ) are shared equally or approximately equally.

[0056] As shown, because the control signal V CR1 The control signal V CR1 The feedback signal FB1 can be changed. For example, the control signal V CR1 As the frequency increases (i.e., as the period T SW1 In this regard, when provided to the feedback network 140a, the control signal V CR1 Can play the role of pushing signal V CR1 Therefore, with respect to the feedback network 140a, without departing from the scope of the present disclosure, the control signal V CR1 It can also be called push signal V CR1 .

[0057] Alternatively, and additionally, because the control signal V CR2 The control signal V CR2 The feedback signal FB1 can also be changed. For example, the control signal V CR2 As the frequency increases (i.e., as the period T SW2 In this regard, when provided to the feedback network 140a, the control signal V CR2 Can play the role of pulling signal V CR2 Therefore, with respect to the feedback network 140a, without departing from the scope of the present disclosure, the control signal V CR2 It can also be called pull signal V CR2 .

[0058] Similarly, as illustrated, the feedback network 140b may receive the output voltage V O , control signal V CR2 and control signal V CR1 , and can provide a feedback signal FB2. Therefore, according to circuit theory, the feedback signal FB2 can depend on the output voltage V O , control signal V CR1 and control signal V CR2 . The control signal V CR1 、VCR2 The DC analysis of the case where the feedback signal FB2 is set to the secondary ground potential makes the output voltage V O Related As About the Voltage Divider Resistor R A2 , R B2 The function of the partial pressure ration.

[0059] According to the teachings of this article, since the control signal V CR1 、V CR2 AC switching behavior, control signal V CR1 、V CR2 The feedback signal FB2 can be adjusted so that the output power of the power converter 100b and the corresponding output current (ie, the output current I L2 ) can be related to the output power of the power converter 100a and the corresponding output current (ie, the output current I L1 ) are shared equally or approximately equally.

[0060] As shown, because the control signal V CR2 The control signal V CR2 The feedback signal FB2 can be changed. For example, the control signal V CR2 As the frequency increases (i.e., as the period T SW2 In this regard, when provided to the feedback network 140b, the control signal V CR2 Can play the role of pushing signal V CR2 Therefore, with respect to the feedback network 140b, without departing from the scope of the present disclosure, the control signal V CR2 It can also be called push signal V CR2 .

[0061] Alternatively, and additionally, because the control signal V CR1 The control signal V CR1 The feedback signal FB2 can also be changed. For example, the control signal V CR2 As the frequency increases (i.e., as the period T SW1 In this regard, when provided to the feedback network 140b, the control signal V CR1 Can play the role of pulling signal V CR1 Therefore, with respect to the feedback network 140a, without departing from the scope of the present disclosure, the control signal V CR1 It can also be called pull signal VCR1 .

[0062] Figure 5 1 illustrates a method for providing a load 142 with a regulated output voltage V O 500. Step 501 may correspond to using a first power converter (eg, power converter 100a). The first power may correspond to an output current (eg, output current I L1 )-related output power. It can be based on the gate signal (for example, the gate signal V CS1 ) frequency to transmit the first power.

[0063] Step 502 may correspond to using a second power converter (eg, power converter 100b). The second power may correspond to an output current (eg, output current I L2 )-related output power. It can be based on the gate signal (for example, the gate signal V CS2 ) frequency to transmit the first power.

[0064] Step 503 may correspond to providing a first control signal (eg, control signal V CR1 ). The first control signal may be applied to a first push-pull feedback network (eg, push-pull feedback network 140a).

[0065] Step 504 may correspond to providing a second control signal (eg, control signal V CR2 ). The second control signal may also be applied to the first push-pull feedback network (eg, push-pull feedback network 140a).

[0066] Step 505 may correspond to providing a first feedback signal (eg, feedback signal FB1 ) in response to the first control signal and the second control signal.

[0067] Step 506 may correspond to load sharing. That is, in response to the first feedback (eg, feedback signal FB1 ), the first power may be substantially equal to the second power.

[0068] In one embodiment, a power converter system (eg, system 50 ) includes a first power converter (eg, power converter 100a ), a second power converter (eg, power converter 100b ), and a first push-pull feedback network (eg, push-pull feedback network 140a ).

[0069] The first power converter includes a first controller circuit (eg, controller circuit 107a). The first controller circuit is configured to generate a first switching frequency (eg, a first switching frequency) according to a first switching frequency (eg, Figure 1The waveforms 191a, 192a in FIG. 1 drive the first switch (eg, the primary switch 152a) so that the first power converter delivers the first power (ie, the output power) to the load 142. The first power may be related to the output current I L1 The output power is related.

[0070] The second power converter includes a second controller circuit (eg, controller circuit 107b). The second controller circuit is configured to provide a second switching frequency (see, for example, Figure 1 The waveforms 191b, 192b in FIG. 1 drive the second switch (eg, primary switch 152b) so that the second power converter delivers the second power (ie, output power) to the load 142. The second power may be a voltage that is proportional to the output current I L2 The output power is related.

[0071] The first push-pull feedback network is configured to receive a first push signal (eg, a control signal V CR2 ) and a first pull signal (control signal V CR1 In response, the first push-pull feedback network provides a first feedback signal (eg, feedback signal FB1) to the first controller circuit such that the first power is substantially equal to the second power.

[0072] In another embodiment, the power converter system includes a second push-pull feedback network (eg, push-pull feedback network 140 b ).

[0073] The second push-pull feedback network is configured to receive a second push signal (eg, a control signal V CR1 ) and a second pull signal (control signal V CR2 In response, the second push-pull feedback network provides a second feedback signal (eg, feedback signal FB2) to the second controller circuit such that the second power is substantially equal to the first power.

[0074] although Figure 1 , Figure 2 and Figure 4 The embodiment illustrates two push-pull feedback networks 140a-140b; however, other configurations may be possible.

[0075] For example, Figure 6 A system 50 of parallel-connected power converters 100a-100b using a push-pull feedback network 140a is illustrated according to another embodiment. In addition to using a push-pull feedback network 140a to achieve load sharing, Figure 6 Implementation plan and Figure 4 As shown in the example, the feedback signal FB2 is obtained by dividing the resistor R A2and the voltage divider resistor R B2 The resistor divider formed is derived.

[0076] in conclusion

[0077] The above description of the illustrated embodiments of the present disclosure, including what is described in the Abstract, is not intended to be exhaustive or to limit the exact form disclosed. Although specific embodiments and embodiments of power converters for parallel connection using a push-pull feedback network are described herein for illustrative purposes, various equivalent modifications are possible without departing from the broader spirit and scope of the present disclosure. In fact, it should be understood that specific example voltages, currents, frequencies, power range values, times, etc. are provided for the purpose of explanation, and other values ​​may also be adopted in other embodiments and embodiments according to the teachings of this article.

[0078] The foregoing description may involve elements or features being "connected," "electrically connected," and / or "coupled" together. As used herein, unless expressly stated otherwise, "electrically connected" and / or "connected" means that one element / feature is directly or indirectly connected to another element / feature, and not necessarily mechanically connected. Similarly, unless expressly stated otherwise, "electrically coupled" and / or "coupled" means that one element / feature is directly or indirectly coupled to another element / feature, and not necessarily mechanically coupled. Therefore, although the various schematic diagrams shown in the accompanying drawings depict example arrangements of elements and components, in an actual embodiment, there may be additional intermediate elements, devices, features, or components (assuming that the functionality of the depicted circuits is not adversely affected).

[0079] Furthermore, conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “eg,” “for example,” “such as,” and the like, unless expressly stated otherwise or otherwise understood in the context of use, is generally intended to convey that certain embodiments include and other embodiments do not include certain features, elements, and / or states. Thus, such conditional language is generally not intended to imply that one or more embodiments require features, elements, and / or states in any way, or that one or more embodiments must include logic for determining whether such features, elements, and / or states are included in any particular embodiment or are to be performed in any particular embodiment.

[0080] Although certain embodiments have been described, these embodiments are presented only by way of example and are not intended to limit the scope of the present disclosure. In fact, the novel devices, methods, and systems described herein may be embodied in various other forms; in addition, various omissions, substitutions, and changes to the forms of the methods and systems described herein may be made without departing from the spirit of the present disclosure. For example, although the disclosed embodiments are presented in a given arrangement, alternative embodiments may perform similar functions with different components and / or circuit topologies, and may delete, move, add, subdivide, combine, and / or modify some elements. Each of these elements may be implemented in a variety of different ways. Any suitable combination of the elements and actions of the embodiments described above may be combined to provide other embodiments. Therefore, the scope of the present invention is limited only by reference to the appended claims.

[0081] Although the claims presented herein are in a single dependent format for filing with the United States Patent and Trademark Office (USPTO), it should be understood that any claim may be dependent on any prior claim of the same type unless that is obviously technically infeasible.

Claims

1. A power converter system, comprising: a first power converter comprising a first controller circuit, wherein the first controller circuit is configured to drive a first switch according to a first switching frequency so that the first power converter delivers a first power to a load; a second power converter comprising a second controller circuit, wherein the second controller circuit is configured to drive a second switch according to a second switching frequency so that the second power converter delivers a second power to the load; as well as A first push-pull feedback network is configured to receive a first push signal at the second switching frequency, receive a first pull signal at the first switching frequency, and in response, provide a first feedback signal to the first controller circuit such that the first power is substantially equal to the second power. 2 . The power converter system of claim 1 , wherein the first power converter is a flyback converter. 3 . The power converter system of claim 1 , wherein the second power converter is a flyback converter.

4. The power converter system of claim 1 , wherein the first controller circuit comprises: Primary controller and secondary controller. 5 . The power converter system of claim 1 , wherein the first power converter is configured to provide a first output current to the load. 6 . The power converter system of claim 5 , wherein the second power converter is configured to provide a second output current to the load. The power converter system of claim 6 , wherein the first output current is substantially equal to the second output current. 8 . The power converter system of claim 6 , wherein the first switching frequency increases monotonically as a function of the first output current. 9 . The power converter system of claim 6 , wherein the second switching frequency increases monotonically as a function of the second output current. 10 . The power converter system of claim 6 , wherein the power converter system is configured to provide a regulated output voltage to the load.

11. The power converter system of claim 1 , further comprising: A second push-pull feedback network is configured to receive a second push signal at the first switching frequency, receive a second pull signal at the second switching frequency, and in response, provide a second feedback signal to the second controller circuit so that the second power is substantially equal to the first power.

12. The power converter system of claim 11, wherein the first controller circuit is configured to provide the first push signal to a gate of a first N-channel field effect transistor (NFET), and wherein the first NFET is a first synchronous rectifier.

13. The power converter system of claim 12, wherein the second controller circuit is configured to provide the second push signal to a gate of a second N-channel field effect transistor (NFET), and wherein the second NFET is a second synchronous rectifier. The power converter system of claim 12 , wherein the first push signal is the second pull signal.

15. The power converter system of claim 12, wherein the second push signal is the first pull signal.

16. A method of providing total power having a regulated output voltage to a load, comprising: using a first power converter to deliver a first power to the load according to a first switching frequency; using a second power converter to deliver a second power to the load according to a second switching frequency; providing a first control signal at the first switching frequency to a first push-pull feedback network; providing a second control signal at the second switching frequency to the first push-pull feedback network; generating a first feedback signal in response to the first control signal and the second control signal; as well as The first power substantially equal to the second power is provided in response to the first feedback signal.

17. The method according to claim 16, further comprising: providing the first control signal at the first switching frequency to a second push-pull feedback network; providing the second control signal at the second switching frequency to the second push-pull feedback network; generating a second feedback signal in response to the first control signal and the second control signal; as well as The second power substantially equal to the first power is provided in response to the second feedback signal. The method of claim 17 , wherein the first power converter is a flyback converter.

19. The method of claim 17, wherein the second power converter is a flyback converter.

20. The method of claim 17, wherein the first switching frequency increases monotonically as a function of the first power.

21. The method of claim 17, wherein the second switching frequency increases monotonically as a function of the second power.

22. A power converter system configured to provide a regulated output voltage to a load and comprising: a first power converter comprising a first controller circuit, wherein the first controller circuit is configured to drive a first switch according to a first switching frequency so that the first power converter provides a first current to the load; a second power converter comprising a second controller circuit, wherein the second controller circuit is configured to drive a second switch according to a second switching frequency so that the second power converter provides a second current to the load; as well as A first push-pull feedback network is configured to receive a first push signal at the second switching frequency, receive a first pull signal at the first switching frequency, and in response, provide a first feedback signal to the first controller circuit such that the first current is substantially equal to the second current.

23. The power converter system of claim 22, further comprising: A second push-pull feedback network is configured to receive a second push signal at the first switching frequency, receive a second pull signal at the second switching frequency, and in response, provide a second feedback signal to the second controller circuit so that the second current is substantially equal to the first current.

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