A multi-module parallel power supply and current sharing method thereof

Abstract

The present invention discloses a multi-module parallel power supply and a current balancing method thereof. The power supply includes multiple power modules. The power level is expanded by connecting the power modules in parallel to meet the demand for power diversity of the power supply output. The first regulating circuit of each slave power module responds to the first output voltage of the master power module, so that when the load changes, the output signal of the first regulating circuit of the slave power module follows the output signal of the first regulating circuit of the master power module, so that the first output current of each power module is approximately balanced.

Description

Technical Field

[0001] The present invention relates to the field of integrated circuits, and more particularly to a power supply with multiple modules connected in parallel and a current balancing method thereof. Background Art

[0002] The most prominent requirement for power supplies is the varying output power levels. An application that can accommodate different power levels allows users to design based on specific needs. By paralleling integrated power chips, power levels can be expanded. This not only saves chip manufacturers development costs and subsequent product management expenses, but also provides users with the autonomy to design based on their specific needs, meeting their demand for diverse switching power outputs and improving user experience. However, paralleling multiple power supplies can lead to current imbalance across the chips.

[0003] At the same time, in order to improve the response speed to the output load, the slope of the inductor current needs to be increased, which means that a smaller inductor needs to be used. At the same time, in order to reduce the switching ripple of the output voltage, a higher switching frequency is required. In the case of large current, a high-frequency switching power supply will bring greater power loss. The combination of a high-frequency switching power supply and a low-frequency switching power supply can obtain the dynamic response speed of a high-frequency switching power supply and an efficiency similar to that of a low-frequency switching power supply.

[0004] Therefore, how to propose an integrated chip based on the combination of high-frequency switching power supply and low-frequency switching power supply to realize a power supply system with multiple modules in parallel and its current sharing method has become one of the problems that technicians in this field need to solve urgently. Summary of the Invention

[0005] In view of this, the present invention proposes a power supply with multiple modules connected in parallel and a current balancing method thereof, which can simultaneously solve the problems of power supply expansion and current balancing of multiple modules connected in parallel.

[0006] In a first aspect, an embodiment of the present invention provides a multi-module parallel power supply, wherein the multi-module parallel power supply comprises at least two power modules, one of which is configured as a master power module and the remaining power modules are configured as slave power modules; output ends of the power modules are interconnected as output ends of the power supply and connected to a load;

[0007] Each power supply module includes a first regulating circuit and a second regulating circuit; a capacitor is connected in series between the output end of the first regulating circuit and the output end of the second regulating circuit, and the output end of the second regulating circuit serves as the output end of the power supply module in which it is located; the first regulating circuit outputs a first output voltage and a first output current, and the second regulating circuit outputs a second output voltage and a second output current;

[0008] The first regulation circuit of each slave power module responds to the error between the first output voltage of the power module in which it is located and the first output voltage of the master power module, so that when the load changes, the output signal of the first regulation circuit of the slave power module follows the output signal of the first regulation circuit of the master power module.

[0009] Preferably, each power supply module includes a balancing circuit, and the balancing circuit of the slave power supply module is configured to output a balancing current based on the error between the first output voltage of the power supply module in which it is located and the first output voltage of the master power supply module, thereby adjusting the duty cycle of the power switch tube in the first regulation circuit.

[0010] Preferably, the balancing circuit is a first transconductance amplifier, the first input end of the first transconductance amplifier of the slave power module is coupled to the output end of the first regulation circuit of the master power module, the second input end is coupled to the output end of the first regulation circuit of the power module, and the balancing current is output to the first regulation circuit of the power module in which it is located.

[0011] Preferably, the first input terminal of the first transconductance amplifier of the main power module is coupled to the output terminal of the first regulating circuit of the power module, and the second input terminal is floating, so that the first transconductance amplifier of the main power module does not work.

[0012] Preferably, the first regulating circuit includes an error compensation circuit, a duty cycle control circuit, a first driving circuit and a first switching conversion circuit;

[0013] The error compensation circuit receives a first reference voltage, the output voltage of the power supply and the balancing current to generate a first control signal; the duty cycle control circuit receives the first control signal and outputs a duty cycle control signal; the first drive circuit receives the duty cycle control signal and outputs a first drive signal; the first drive signal is used to drive the power switch tube in the first switching conversion circuit, and the output of the first switching conversion circuit is the output of the first regulation circuit.

[0014] Preferably, the first switching conversion circuit includes a first power switch tube, a second power switch tube and a first output inductor; the first power switch tube and the second power switch tube are connected in series between the power supply voltage and the reference ground, the common connection end of the first power switch tube and the second power switch tube is connected to one end of the first output inductor, and the other end of the first output inductor serves as the output end of the first regulation circuit.

[0015] Preferably, the error compensation circuit includes a second transconductance amplifier and a compensation network connected in series to the output terminal of the second transconductance amplifier and the ground terminal; the first input terminal of the second transconductance amplifier receives the first reference voltage, the second input terminal receives the output voltage of the power supply, and the output terminal is connected to the output terminal of the balancing circuit.

[0016] Preferably, the second regulation circuit of each power module responds to the first output voltage of the main power module, thereby adjusting the output signal of the second regulation circuit of each power module according to the first output voltage of the main power module, so that the second output current of all power modules reaches a uniform current.

[0017] Preferably, the second regulation circuit includes an error amplifier, a current feedback control circuit, a second drive circuit and a second switching conversion circuit; the error amplifier receives a second reference voltage and the first output voltage of the main power supply module, and outputs a second control signal; the current feedback control circuit receives the second control signal and the current flowing through the output inductor in the second switching conversion circuit, and outputs a switching control signal; the second drive circuit receives the switching control signal and outputs a second drive signal; the second drive signal is used to drive the power switch tube in the second switching conversion circuit, and the output of the second switching conversion circuit is the output of the second regulation circuit.

[0018] Preferably, the second switching conversion circuit includes a third power switch tube, a fourth power switch tube and a second output inductor; the third power switch tube and the fourth power switch tube are connected in series between the power supply voltage and the reference ground, the common connection end of the third power switch tube and the fourth power switch tube is connected to one end of the second output inductor, and the other end of the second output inductor serves as the output end of the second regulation circuit.

[0019] Preferably, the current feedback control circuit adopts a peak current control mode, a valley current control mode or a bang-bang current control mode.

[0020] Preferably, the switching frequency of the power switch tube in the first regulation circuit is higher than the switching frequency of the power switch tube in the second regulation circuit, so that the first regulation circuit responds to load changes faster than the second regulation circuit.

[0021] In a second aspect, an embodiment of the present invention further provides a current sharing method for a multi-module parallel power supply, wherein the power supply includes at least two power modules, one of which is configured as a master power module and the remaining power modules are configured as slave power modules; the output ends of the power modules are interconnected as the output ends of the power supply and are connected to a load;

[0022] Each power module includes a first regulating circuit and a second regulating circuit; a capacitor is connected in series between the output ends of the first regulating circuit and the second regulating circuit, and the output end of the second regulating circuit serves as the output end of the power module in which it is located; the first regulating circuit outputs a first output voltage and a first output current, and the second regulating circuit outputs a second output voltage and a second output current;

[0023] The first regulation circuit of each slave power module responds to the error between the first output voltage of the power module in which it is located and the first output voltage of the master power module, so that when the load changes, the output signal of the first regulation circuit of the slave power module follows the output signal of the first regulation circuit of the master power module, thereby achieving equal flow of the first output current of each power module.

[0024] Preferably, the first regulation circuit of each slave power module responds to the first output voltage of the power module to which it is located and the first output voltage of the master power module, and includes the following steps: converting the difference between the first output voltage of the master power module and the first output voltage of the slave power module into a balancing current; and adjusting the output signal of the first regulation circuit of the power module to which it is located based on the balancing current, so that the output signal of the first regulation circuit of each slave power module follows the output signal of the first regulation circuit of the master power module.

[0025] Preferably, the first regulating circuit of each slave power module is also responsive to the output voltage of the power supply, so that each slave power module further regulates the output signal of the first regulating circuit according to the output voltage of the power supply.

[0026] Preferably, each slave power supply module also adjusts the output signal of the first regulation circuit according to the output voltage of the power supply, including the following steps: when the load changes, the output voltage of the power supply changes, and the first control signal is adjusted according to the error between the first reference voltage and the power supply output voltage and the balancing current; the duty cycle control signal is adjusted according to the first control signal; the first drive signal is adjusted according to the duty cycle control signal; and the power switch tube in the first regulation circuit is driven according to the first drive signal, thereby adjusting the output signal of the first regulation circuit.

[0027] Preferably, when the load changes, the output signal of the power supply is controlled to change by adjusting the output signals of the first regulation circuit and the second regulation circuit, so that in the regulation process to reach a steady state, the output voltage of the power supply gradually approaches the first reference voltage.

[0028] Preferably, the second regulating circuit of each power module is regulated according to the first output voltage of the main power module, so that the second output current of all power modules reaches a uniform current.

[0029] Preferably, the second regulation circuit of each power module is regulated according to the first output voltage of the main power module, including the following steps: adjusting the second control signal according to the error between the second reference voltage and the first output voltage of the main power module; adjusting the switch control signal according to the second control signal and the current flowing through the second output inductor in the second regulation circuit; adjusting the second drive signal according to the switch control signal; driving the power switch tube in the second regulation circuit according to the second drive signal, thereby adjusting the output signal of the second regulation circuit.

[0030] Preferably, the switch control signal is adjusted according to the second control signal and the current flowing through the output inductor in the second regulation circuit to adopt a peak current control mode, a valley current control mode or a bang-bang current control mode.

[0031] Preferably, the switching frequency of the power switch tube in the first regulation circuit is higher than the switching frequency of the power switch tube in the second regulation circuit, so that the first regulation circuit responds to load changes faster than the second regulation circuit.

[0032] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0033] 1. The present invention realizes the expansion of power levels by connecting power modules in parallel, meeting the demand for power diversity of power supply output;

[0034] 2. The present invention realizes current sharing among different parallel modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0036] Figure 1 Schematic diagram of a power supply with multiple modules connected in parallel according to an embodiment of the present invention;

[0037] Figure 2 Schematic diagram of the circuit of the power module in this embodiment;

[0038] Figure 3 This is a circuit diagram of two power modules connected in parallel according to an embodiment of the present invention;

[0039] Figure 4 This is a first working waveform diagram of an embodiment of the present invention;

[0040] Figure 5 This is a second working waveform diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The present invention is described below based on the following embodiments, but the present invention is not limited to these embodiments. In the detailed description of the present invention below, certain specific details are described in detail. Those skilled in the art can fully understand the present invention without these details. To avoid obscuring the essence of the present invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0042] Furthermore, persons of ordinary skill in the art will appreciate that the figures provided herein are for illustration purposes only and are not necessarily drawn to scale.

[0043] At the same time, it should be understood that in the following description, "circuit" refers to a conductive loop composed of at least one element or subcircuit connected electrically or electromagnetically. When an element or circuit is said to be "connected to" another element or an element / circuit is said to be "connected" between two nodes, it can be directly coupled or connected to the other element or there can be intermediate elements. The connection between the elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there are no intermediate elements between the two.

[0044] Example 1

[0045] like Figure 1 As shown, this embodiment discloses a multi-module parallel power supply, which includes N power modules: a first power module 1, a second power module 2, ... an Nth power module n, one of which is a master power module and the remaining power modules are slave power modules; the output ends of each power module are connected in parallel to each other as the output end of the power supply to generate an output voltage Vout, which is provided to the load, and the output end of the power supply is connected to a grounded capacitor C0, where N is a positive integer, N ≥ 2. Each power module includes a first regulation circuit 11 and a second regulation circuit 12; a capacitor C is connected in series between the output ends of the first regulation circuit 11 and the second regulation circuit 12. AC The output end of the second regulating circuit 12 is connected as the output end of the power module; the first regulating circuit 11 outputs a first output voltage and a first output current, and the second regulating circuit 12 outputs a second output voltage and a second output current.

[0046] The first regulation circuit 11 of each slave power module responds to the first output voltage of the power module in which it is located and the first output voltage VAC1 of the master power module, so that when the load changes, the output signal of the first regulation circuit 11 of the slave power module follows the output signal of the first regulation circuit 11 of the master power module, that is, the first output voltage of the slave power module follows the first output voltage of the master power module, and the first output current of the slave power module follows the first output current of the master power module, so that the first output current of each power module reaches equal current.

[0047] Specifically, if Figure 2 As shown, each power supply module further includes a balancing circuit 13, which is a first transconductance amplifier g m-1 When the power supply module is a slave power supply module, the first transconductance amplifier g m-1 The first input end is coupled to the output end of the first regulating circuit 11 of the main power module, and the second input end is coupled to the output end of the first regulating circuit 11 of the power module where the power module is located; when the power module is the main power module, the first transconductance amplifier g m-1 The first input terminal of the first transconductance amplifier is coupled to the output terminal of the first regulating circuit 11 of the power module, and the second input terminal is floating, so that the balancing circuit 13 in the main power module does not work. m-1 Output balancing current to the first regulating circuit 11 of the power module where it is located; that is, the balancing circuit 13 is used to detect the error between the first output voltage of the power module where it is located and the first output voltage of the main power module, so that the output signal of the first regulating circuit of the slave power module follows the output signal of the first regulating circuit of the main power module.

[0048] The second regulation circuit 12 of each power module responds to the first output voltage of the main power module, thereby adjusting the output signal of the second regulation circuit 12 of each power module according to the first output voltage of the main power module, so that the second output current of all power modules reaches a balanced current.

[0049] like Figure 2 As shown, the first regulation circuit 11 includes an error compensation circuit 111, a duty cycle control circuit 112, a first drive circuit 113, and a first switching conversion circuit 114. The error compensation circuit 111 receives a first reference voltage Vref1, an output voltage Vout of a power supply, and a balancing current to generate a first control signal. The duty cycle control circuit 112 receives the first control signal and outputs a duty cycle control signal. The first drive circuit 113 receives the duty cycle control signal and outputs a first drive signal. The first drive signal is used to drive the power switch in the first switching conversion circuit 114. The output of the first switching conversion circuit 114 serves as the output of the first regulation circuit 11. The first switching conversion circuit 114 includes a first power switch Q1, a second power switch Q2, and a first output inductor LAC. The first power switch Q1 and the second power switch Q2 are connected in series between a power supply voltage VIN and a reference ground GND. The common connection terminal of the first power switch Q1 and the second power switch Q2 is connected to one end of the first output inductor LAC. The other end of the first output inductor LAC serves as the output terminal of the first regulation circuit.

[0050] Specifically, if Figure 2 As shown, the error compensation circuit 111 includes a second transconductance amplifier g m-2and connected in series to the second transconductance amplifier g m-2 The compensation network between the output terminal and the ground terminal, in this embodiment, the compensation network includes a resistor R and a capacitor C connected in series; the second transconductance amplifier g m-2 The first input terminal receives the first reference voltage Vref1, and the second input terminal receives the output voltage Vout of the power supply; the output terminal of the balancing circuit 13 and the second transconductance amplifier g m-2 The output of the second transconductance amplifier is connected so that the current is balanced and g m-2 The output current jointly regulates the second transconductance amplifier g m-2 The voltage VC at the output node changes.

[0051] It should be noted that the difference between the slave power module and the master power module is that there is an additional balancing circuit. The existence of the balancing circuit makes the first output current of the slave power module follow the first output current of the master power module, and the first output voltage of the slave power module follow the first output voltage VAC of the master power module; However, in actual circuit design, due to some non-ideal reasons, the second transconductance amplifier g of each power module may be m-2 The potential of the first input terminal may not be equal, and the second transconductance amplifier g of each power module m-2 The error in the potential of the first input terminal does not affect the change of the first output voltage of each slave power module following the first output voltage VAC of the master power module, but the error will cause a DC offset between the first output voltages of each power module.

[0052] like Figure 2 As shown, the second regulation circuit 12 includes an error amplifier 121, a current feedback control circuit 122, a second drive circuit 123 and a second switch conversion circuit 124; the error amplifier 121 receives the second reference voltage Vref2 and the first output voltage of the main power module, and outputs a second control signal proportional to the error between the two according to the error between the two; the current feedback control circuit 122 receives the second control signal and the current flowing through the second output inductor LDC in the second switch conversion circuit 124, and outputs a switch control signal; the second drive circuit 123 outputs a second drive signal according to the switch control signal to drive the second switch The power switch tube in the conversion circuit 124, the output of the second switching conversion circuit 124 is the output of the second regulation circuit 12; the second switching conversion circuit 124 includes a third power switch tube Q3, a fourth power switch tube Q4 and a second output inductor LDC; the third power switch tube Q3 and the fourth power switch tube Q4 are connected in series between the power supply voltage VIN and the reference ground GND, the common connection terminal of the third power switch tube Q3 and the fourth power switch tube Q4 is connected to one end of the second output inductor LDC, and the other end of the second output inductor LDC serves as the output end of the second regulation circuit 12.

[0053] It should be noted that, in this embodiment, the power supply voltages of the second switching conversion circuit 124 and the first switching conversion circuit 114 are equal, and in other embodiments they may be different power supply voltages, which is not limited here. Figure 2 As shown, the first switch conversion circuit 114 and the capacitor C AC The first switching conversion circuit 114 and the second switching conversion circuit 124 and the grounding capacitor C0 form a Buck circuit. It should be noted that the first switching conversion circuit 114 and the second switching conversion circuit 124 include but are not limited to those listed in this embodiment, and can also be a boost converter, a buck-boost converter, or any DC-DC converter that meets the requirements of the present invention. They are not listed here one by one. In this embodiment, the first transconductance amplifier g m-1 , the second transconductance amplifier g m-2 The first input terminal of the error amplifier 121 is the non-inverting terminal of the amplifier, and the second input terminal is the inverting terminal of the amplifier; similarly, the first input terminal of each amplifier can also be the inverting terminal of the amplifier, and the second input terminal is the non-inverting terminal of the amplifier, and it is only necessary to make corresponding adjustments to its received signal.

[0054] Specifically, the current feedback control circuit 122 can adopt a peak current control mode, a valley current control mode, or a bang-bang current control mode. As a current mode control mode, during the circuit regulation process, the current feedback control circuit 122 receives the second control signal and also receives the second output current i flowing through the second output inductor LDC. LDC Therefore, changes in the current of the second output inductor LDC will immediately cause changes in the entire loop, rather than being sampled by the entire loop only after the inductor current changes and the output voltage changes in the voltage control mode. Therefore, current mode control improves the response speed of the second regulation circuit 12 and has better load regulation and linear regulation. As an example, when the control mode is valley current mode, the on-time of the power switch tube Q3 in the second regulation circuit 12 is maintained for a preset time. When the on-time of the power switch tube Q3 reaches the preset time, the power switch tube Q3 enters the off stage, and then the second output current i flowing through the second output inductor LDC is detected. LDC , wherein the second control signal is adjusted according to the error between the first output voltage VAC1 of the main power module and the second reference voltage Vref2, thereby controlling the second output current i LDC The valley value of the second output current i LDC When the value is lower than the valley value, a switching cycle of the power switch tube Q3 ends, and the power switch tube Q3 enters the conduction phase of the next switching cycle; that is, according to the second output current i LDCThe first output voltage VAC1 of the main power module regulates the switching cycle of the power switch tubes Q3 and Q4 in the second regulating circuit 12, thereby regulating the second output current i LDC Similarly, the off time of the power switch Q3 can also be set to maintain a preset value, and the second output current i flowing through the second output inductor LDC is controlled according to the first output voltage VAC1 of the main power module. LDC As another example, when the control mode is the peak current mode, the switching period of the power switch tube in the second regulation circuit 12 is kept at the preset value, and the first output voltage VAC1 of the main power module controls the second output current i LDC The peak value of the second output current i is adjusted according to the second control signal to adjust the off or on time of the power switch tubes Q3 and Q4 in the second regulation circuit 12 to adjust the duty cycle of the power switch tubes Q3 and Q4, thereby adjusting the second output current i LDC As another example, when the control module is in bang-bang mode, the first output voltage VAC1 of the main power module not only controls the second output current i LDC The peak value also controls the second output current i LDC The valley value of the second output current i is adjusted according to the second control signal to adjust the turn-off and turn-on time of the power switch tubes Q3 and Q4 in the second regulating circuit 12, thereby adjusting the second output current i LDC It should be noted that, in this embodiment, when the voltage of the first output voltage VAC1 of the main power module is higher, the second output current i LDC The bigger.

[0055] More specifically, the operating frequency of the first switching conversion circuit 114 is higher than the operating frequency of the second switching conversion circuit 124, so that the first regulating circuit 11 responds to load changes faster than the second regulating circuit 12. For example, the first switching conversion circuit 114 operates at 30MHz, and the inductance of the first output inductor LAC is relatively small, such as 10nH; the second switching conversion circuit 124 operates at a lower switching frequency of 3MHz, and the inductance of the second output inductor LDC is relatively large, such as 100nH. In this embodiment, the output terminals of the first regulating circuit 11 and the second regulating circuit 12 are connected through capacitors C AC The capacitor acts as a DC blocker, prohibiting the first regulating circuit 11 from providing DC current to the output end of the power supply. Therefore, the function of the first switching conversion circuit 114 is to reduce the ripple of the output voltage and provide instantaneous current for dynamic response when the load changes. When the steady state is reached, the average current of the output of the first switching conversion circuit 114 is 0, that is, the average value of the first output current is 0, and the second regulating circuit 12 provides DC current to the load.

[0056] It should be further explained that if Figure 1 and Figure 2 As shown, in this embodiment, each power module has a first output inductor LAC of the first switching conversion circuit 114, a second output inductor LDC of the second switching conversion circuit 124, and a capacitor C connected to the output terminals of the first regulating circuit 11 and the second regulating circuit 12. AC Except for the grounding capacitor C0 connected to the power output terminal, the rest of the circuits are integrated into one chip. The SWA pin of the chip represents the common connection terminal of the power switches Q1 and Q2 of the first switching conversion circuit 114, and the SWD pin represents the common connection terminal of the power switches Q3 and Q4 of the second switching conversion circuit 124; the ISH pin is used to obtain the output signal of the first regulation circuit of the power module where it is located, and to communicate with the first transconductance amplifier g m-1 The FBD pin receives the first output voltage VAC1 of the main power module and can also receive a feedback signal V representing the first output voltage VAC1 of the main power module. FBD ( Figure 1 The FBD pin is directly connected to the output of the first regulating circuit 11 of the main power module. FBD FBD pin can also be connected to the output of the sampling circuit for sampling the first output voltage of the main power module), and with the first transconductance amplifier g m-1 The FBA pin receives the output voltage Vout of the power supply and can also receive a feedback signal V representing the output voltage Vout of the power supply. FBA ( Figure 1 The FBA pin is directly connected to the output of the power supply. FBA The FBA pin can also be connected to the output end of the sampling circuit for sampling the output voltage Vout of the power supply, and connected to the second transconductance amplifier g m-2 The VINAC and VINAC pins are connected to the power supply of the first switching converter circuit 114 and the second switching converter circuit 124, respectively. The FBD pins of all power modules are connected to the output of the main power module. Since the FBD pin voltages of all power modules are equal, the second output currents output by the second regulating circuits 12 of all power modules are also equal.

[0057] Example 2

[0058] This embodiment provides a current balancing method for a multi-module parallel power supply. For the convenience of explanation, the current balancing method of this embodiment is explained based on the multi-module parallel power supply in Example 1. However, it should be noted that the implementation of this method includes but is not limited to the implementation of the composition of the multi-module parallel power supply in Example 1.

[0059] The current sharing of multiple modules in parallel is realized through the first transconductance amplifier g m-1 The implementation is performed so that the output signal of the first regulating circuit 11 of each slave power module follows the output of the first regulating circuit 11 of the master power module, so that the first output current of each power module reaches a current balance, and the first output voltage of the slave power module follows the first output voltage of the master power module, which specifically includes the following steps:

[0060] The first transconductance amplifier g m-1 Convert the difference between the first output voltage VAC1 of the master power module and the first output voltage of the slave power module into a balancing current;

[0061] The balancing current makes the second transconductance amplifier g m-2 The voltage VC at the output node changes;

[0062] The change of the voltage VC can regulate the output of the first regulating circuit of the slave power module.

[0063] Specifically, when the load changes, the output of the power supply is controlled to change by adjusting the outputs of the first and second regulation circuits. That is, the first path is to adjust the first output voltage and the first output current through the first regulation circuit 11; the second path is to adjust the second output voltage and the second output current through the second regulation circuit 12. Changes in the first and second output currents control the output voltage of the power supply to change, thereby adjusting the output voltage of the power supply to approach the first reference voltage Vref1.

[0064] The first path is performed through the first regulating circuit 11. At the same time, the output of the first regulating circuit 11 of each slave power module is adjusted according to the balancing current and also changes according to the first output voltage VAC1 of the master power module, including the following steps:

[0065] When the load changes, the output voltage Vout of the power supply changes and is input into the second transconductance amplifier g m-2 The difference between the first reference voltage Vref1 and the output voltage Vout of the power supply changes;

[0066] Adjusting the first control signal output by the error compensation circuit 111 according to the difference between the first reference voltage Vref1 and the output voltage Vout of the power supply and the balancing current;

[0067] Adjusting the duty cycle control signal output by the duty cycle control circuit 112 according to the first control signal;

[0068] adjusting the duty cycle of the first driving signal output by the first driving circuit 113 according to the duty cycle control signal;

[0069] The power switches Q1 and Q2 in the first switching conversion circuit 114 are driven according to the first driving signal, thereby regulating the output of the first regulating circuit 11 .

[0070] It should be noted that the balancing circuit of the main power module is not working, so the duty cycle control circuit 112 of the first regulation circuit of the main power module only changes according to the output signal of the error compensation circuit 111, so the rest of the working process of the main power module is the same as the working process of the first regulation circuit of the slave power module.

[0071] Specifically, when the load changes, the output of the power supply is controlled to change by adjusting the output of the first regulating circuit 11 and the second regulating circuit 12, so that in the process of reaching a steady state, the current flowing into the grounded capacitor C0 connected to the output end of the power supply gradually approaches 0, thereby making the output voltage of the power supply gradually approach a constant.

[0072] At the same time, when the load changes, the second path is to adjust the second output voltage and the second output current through the second regulation circuit 12, which adjusts the output of the second regulation circuit 12 according to the output of the first regulation circuit 11 of the main power module, including the following steps:

[0073] Adjust the second control signal output by the error amplifier 121 according to the difference between the first output voltage VAC1 of the main power module and the second reference voltage Vref2;

[0074] The current feedback control circuit 122 adjusts the output switch control signal according to the second control signal and the current flowing through the output inductor LDC in the second switch conversion circuit 124;

[0075] The second driving circuit 123 adjusts the output second driving signal according to the switch control signal;

[0076] The power switches Q3 and Q4 in the second switching conversion circuit 124 are driven according to the second driving signal, thereby regulating the output of the second regulating circuit 12 .

[0077] Specifically, combined Figure 3 and Figure 4 The regulation process of two power modules in parallel is described as follows: when the load jumps from light load to heavy load, the current flowing through the load increases, the output voltage Vout of the power supply decreases and is less than the first reference voltage Vref1, the difference between the first reference voltage Vref1 and the power output voltage Vout increases, the duty cycle of the main power switches Q11 and Q21 of the first regulation circuit 11 of the master power module 1 and the slave power module 2 increases, and the main power switches Q11 and Q21 of the first switching conversion circuit are closed for a longer time in each switching cycle, and the first output current i LAC1 、i LAC2and the first output voltage VAC1, VAC2 increases; the increase of the first output voltage VAC1, VAC2 of the master power module 1 and the slave power module 2 makes the first output voltage VAC1 of the master power module greater than the second reference voltage Vref2, so that the voltage of the second control signal output by the error amplifier 121 increases, and the increase of the output voltage of the error amplifier 121 of the master power module 1 and the slave power module 2 causes the second drive signal generated by the current feedback control circuit 122 to drive the power switch tubes Q13, Q14, Q23, Q24 in the second switching conversion circuit 124, thereby making the second output current i of the master power module 1 and the slave power module 2 LDC1 、i LDC2 The first output current i of the master power module 1 and the slave power module 2 increases in a positive direction; LAC1 、i LAC2 and the second output current i LDC1 、i LDC2 As the voltage Vout of the power supply increases, the output voltage Vout of the power supply is controlled to increase, thereby adjusting the output voltage Vout of the power supply to gradually approach the first reference voltage Vref1.

[0078] Specifically, combined Figure 3 and Figure 5 The regulation process when the load changes from heavy load to light load when two power modules are connected in parallel is described as follows: when the load changes from heavy load to light load, the output voltage Vout of the power supply increases, the absolute difference between the first reference voltage Vref1 and the output voltage Vout of the power supply increases, the duty cycle of the main power switch tubes Q11 and Q21 of the first regulation circuit 11 of the master power module 1 and the slave power module 2 decreases, and the first output current i LAC1 、i LAC2 The first output voltages VAC1 and VAC2 decrease in the reverse direction; the decrease in the first output voltages VAC1 and VAC2 of the master power module 1 and the slave power module 2 makes the first output voltage VAC1 of the master power module less than the second reference voltage Vref2, so that the voltage of the second control signal output by the error amplifier 121 of the master power module 1 and the slave power module 2 decreases, and the decrease in the output voltage of the error amplifier 121 causes the second drive signal generated by the current feedback control circuit 122 to drive the power switch tubes Q13, Q14, Q23, and Q24 in the second switching conversion circuit 124, thereby making the second output current i LDC1 、i LDC2 The first output current i of the master power module 1 and the slave power module 2 are both reduced; LAC1 、i LAC2 and the second output current i LDC1 、i LDC2The output voltage Vout of the power supply is controlled to decrease, thereby adjusting the output voltage Vout of the power supply to gradually approach the first reference voltage Vref1.

[0079] In summary, an embodiment of the present invention provides a power supply with multiple modules connected in parallel and a current balancing method thereof, wherein the power supply includes N power modules: a first power module 1, a second power module 2...an Nth power module n, wherein one power module is a master power module and the remaining power modules are slave power modules; the output ends of each power module are coupled to each other as the output ends of the power supply and connected to the load; each power module includes a first regulation circuit 11 and a second regulation circuit 12; the output ends of the first regulation circuit 11 and the second regulation circuit 12 are coupled to each other as the outputs of the power module; the first regulation circuit 11 outputs a first output voltage and a first output current, and the second regulation circuit 12 outputs a second output voltage and a second output current; the first regulation circuit 11 of each slave power module responds to the first output voltage of the power module in which it is located and the first output voltage VAC1 of the master power module, so that when the load changes, the output signal of the first regulation circuit 11 of the slave power module follows the output signal of the first regulation circuit 11 of the master power module, so that the first output current of each power module is approximately current-balanced. The present invention realizes the expansion of power levels by parallel connection of power modules, meeting the demand for power diversity of power supply output; the first regulation circuit 11 of each slave power module of the present invention responds to the first output voltage VAC1 of the master power module, realizing current sharing between different parallel modules.

[0080] While embodiments of the present invention have been described above, these embodiments do not exhaustively describe all details and do not limit the invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the above description. These embodiments are selected and described in detail in this specification in order to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better utilize the present invention and its modifications. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A power supply with multiple modules connected in parallel, characterized by: The power supply includes at least two power modules, one of which is configured as a master power module and the remaining power modules are configured as slave power modules; the output ends of the power modules are connected to each other as the output ends of the power supply and are connected to the load; Each power supply module includes a first regulating circuit and a second regulating circuit; a capacitor is connected in series between the output end of the first regulating circuit and the output end of the second regulating circuit, and the output end of the second regulating circuit serves as the output end of the power supply module in which it is located; The first regulating circuit outputs a first output voltage and a first output current, and the second regulating circuit outputs a second output voltage and a second output current; The first regulation circuit of each slave power module responds to the error between the first output voltage of the power module in which it is located and the first output voltage of the master power module, so that when the load changes, the output signal of the first regulation circuit of the slave power module follows the output signal of the first regulation circuit of the master power module; the second regulation circuit of each power module responds to the first output voltage of the master power module, thereby adjusting the output signal of the second regulation circuit of each power module according to the first output voltage of the master power module, so that the second output current of all power modules reaches a balanced current.

2. The multi-module parallel power supply according to claim 1, characterized in that: Each power supply module includes a balancing circuit, and the balancing circuit of the slave power supply module is configured to output a balancing current based on the error between the first output voltage of the power supply module in which it is located and the first output voltage of the master power supply module, thereby adjusting the duty cycle of the power switch tube in the first regulation circuit.

3. The multi-module parallel power supply according to claim 2, characterized in that: The balancing circuit is a first transconductance amplifier, and the first input end of the first transconductance amplifier of the slave power module is coupled to the output end of the first regulation circuit of the master power module, and the second input end is coupled to the output end of the first regulation circuit of the power module, outputting the balancing current to the first regulation circuit of the power module in which it is located.

4. The multi-module parallel power supply according to claim 3, characterized in that: The first input terminal of the first transconductance amplifier of the main power module is coupled to the output terminal of the first regulating circuit of the power module, and the second input terminal is floating, so that the first transconductance amplifier of the main power module does not work.

5. The multi-module parallel power supply according to claim 3, characterized in that: The first regulating circuit includes an error compensation circuit, a duty cycle control circuit, a first driving circuit and a first switching conversion circuit; The error compensation circuit receives a first reference voltage, the output voltage of the power supply and the balancing current to generate a first control signal; The duty cycle control circuit receives the first control signal and outputs a duty cycle control signal; The first driving circuit receives the duty cycle control signal and outputs a first driving signal; The first driving signal is used to drive the power switch tube in the first switching conversion circuit, and the output of the first switching conversion circuit is the output of the first regulating circuit.

6. The multi-module parallel power supply according to claim 5, characterized in that: The first switching conversion circuit includes a first power switch tube, a second power switch tube and a first output inductor; the first power switch tube and the second power switch tube are connected in series between the power supply voltage and the reference ground, the common connection end of the first power switch tube and the second power switch tube is connected to one end of the first output inductor, and the other end of the first output inductor serves as the output end of the first regulation circuit.

7. The multi-module parallel power supply according to claim 5, characterized in that: The error compensation circuit includes a second transconductance amplifier and a compensation network connected in series to the output terminal of the second transconductance amplifier and the ground terminal; the first input terminal of the second transconductance amplifier receives the first reference voltage, the second input terminal receives the output voltage of the power supply, and the output terminal is connected to the output terminal of the balancing circuit.

8. The multi-module parallel power supply according to claim 1, characterized in that: The second regulating circuit includes an error amplifier, a current feedback control circuit, a second driving circuit and a second switching conversion circuit; The error amplifier receives a second reference voltage and the first output voltage of the main power module and outputs a second control signal; The current feedback control circuit receives the second control signal and the current flowing through the output inductor of the second switching conversion circuit, and outputs a switching control signal; The second driving circuit receives the switch control signal and outputs a second driving signal; The second driving signal is used to drive the power switch tube in the second switching conversion circuit, and the output of the second switching conversion circuit is the output of the second regulating circuit.

9. The multi-module parallel power supply according to claim 8, characterized in that: The second switching conversion circuit includes a third power switch tube, a fourth power switch tube and a second output inductor; the third power switch tube and the fourth power switch tube are connected in series between the power supply voltage and the reference ground, the common connection end of the third power switch tube and the fourth power switch tube is connected to one end of the second output inductor, and the other end of the second output inductor serves as the output end of the second regulation circuit.

10. The multi-module parallel power supply according to claim 8, characterized in that: The current feedback control circuit adopts a peak current control mode, a valley current control mode or a bang-bang current control mode.

11. The multi-module parallel power supply according to claim 1, characterized in that: The switching frequency of the power switch tube in the first regulation circuit is higher than the switching frequency of the power switch tube in the second regulation circuit, so that the first regulation circuit responds to load changes faster than the second regulation circuit.

12. A current sharing method for multi-module parallel power supplies, characterized by: The power supply includes at least two power modules, one of which is configured as a master power module and the remaining power modules are configured as slave power modules; the output ends of the power modules are connected to each other as the output ends of the power supply and are connected to the load; Each power supply module includes a first regulating circuit and a second regulating circuit; a capacitor is connected in series between the output ends of the first regulating circuit and the second regulating circuit, and the output end of the second regulating circuit serves as the output end of the power supply module in which it is located; The first regulating circuit outputs a first output voltage and a first output current, and the second regulating circuit outputs a second output voltage and a second output current; The first regulating circuit of each slave power module responds to the error between the first output voltage of the power module in which it is located and the first output voltage of the master power module, so that when the load changes, the output signal of the first regulating circuit of the slave power module follows the output signal of the first regulating circuit of the master power module, thereby achieving a balanced first output current of each power module; The second regulating circuit of each power module is regulated according to the first output voltage of the main power module, so that the second output current of all power modules reaches a uniform current.

13. The current sharing method for multi-module parallel power supplies according to claim 12, characterized in that: The first regulating circuit of each slave power module responds to the first output voltage of the power module in which it is located and the first output voltage of the master power module, including the following steps: Converting a difference between the first output voltage of the master power module and the first output voltage of the slave power module into a balancing current; The output signal of the first regulating circuit of the power module is adjusted based on the balancing current, so that the output signal of the first regulating circuit of each slave power module follows the output signal of the first regulating circuit of the master power module.

14. The current sharing method for multi-module parallel power supplies according to claim 13, characterized in that: The first regulating circuit of each slave power module is also responsive to the output voltage of the power supply, so that each slave power module further regulates the output signal of the first regulating circuit according to the output voltage of the power supply.

15. The current sharing method for multi-module parallel power supplies according to claim 14, characterized in that: Each slave power supply module further adjusts the output signal of the first regulating circuit according to the output voltage of the power supply, including the following steps: When the load changes, the output voltage of the power supply changes, and the first control signal is adjusted according to the error between the first reference voltage and the output voltage of the power supply and the balancing current; adjusting a duty cycle control signal according to the first control signal; adjusting the first drive signal according to the duty cycle control signal; The power switch tube in the first regulating circuit is driven according to the first driving signal, thereby regulating the output signal of the first regulating circuit.

16. The current sharing method for multi-module parallel power supplies according to claim 15, characterized in that: When the load changes, the output signal of the power supply is controlled to change by adjusting the output signals of the first regulating circuit and the second regulating circuit, so that in the regulation process of reaching a steady state, the output voltage of the power supply gradually approaches the first reference voltage.

17. The current sharing method for multi-module parallel power supplies according to claim 12, characterized in that: The second regulating circuit of each power module performs regulation according to the first output voltage of the main power module, including the following steps: adjusting a second control signal according to an error between a second reference voltage and the first output voltage of the main power module; adjusting a switch control signal according to the second control signal and a current flowing through a second output inductor in the second regulating circuit; adjusting the second driving signal according to the switch control signal; The power switch tube in the second regulating circuit is driven according to the second driving signal, thereby regulating the output signal of the second regulating circuit.

18. The current sharing method for multi-module parallel power supplies according to claim 17, characterized in that: The switch control signal is adjusted according to the second control signal and the current flowing through the output inductor in the second regulation circuit to adopt a peak current control mode, a valley current control mode or a bang-bang current control mode.

19. The current sharing method for multi-module parallel power supplies according to claim 12, characterized in that: The switching frequency of the power switch tube in the first regulation circuit is higher than the switching frequency of the power switch tube in the second regulation circuit, so that the first regulation circuit responds to load changes faster than the second regulation circuit.

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