Control method, controller, converter and system of direct current-direct current conversion circuit

Abstract

The invention discloses a control method of a DC-DC conversion circuit, a controller, a converter and a system. The control method of the DC-DC conversion circuit comprises the following steps: controlling the first switch group and the second switch group to be switched on alternately; when the actual load power of the DC-DC conversion circuit is greater than the preset power, the synchronous rectification circuit is controlled to work in a first mode, and in the first mode, the first rectification switch tube and the first switch group are complementarily conducted, and the second rectification switch tube and the second switch group are complementarily conducted; and when the actual load power of the DC-DC conversion circuit is smaller than or equal to the preset power, the synchronous rectification circuit is controlled to work in a second mode, and in the second mode, the first rectification switch tube and the second switch group are switched on and off at the same time, and the second rectification switch tube and the first switch group are switched on and off at the same time. According to the control method of the DC-DC conversion circuit provided by the embodiment of the invention, the efficiency of the DC-DC conversion circuit in a light load state can be improved.

Description

Technical Field

[0001] The present application relates to the field of power supply circuits, and in particular to a control method, a controller, a converter and a system for a DC-DC conversion circuit. Background Art

[0002] The direct current-to-direct current (DC-DC) conversion circuit includes a synchronous rectification circuit connected to the secondary winding of the transformer. The synchronous rectification circuit may include a diode and a rectification switch tube, both of which serve as rectification elements. In the related art, when the DC-to-DC conversion circuit is under a heavy load, the rectification switch tube starts to work, and when the DC-to-DC conversion circuit is under a light load, the rectification switch tube stops working and only rectifies through the diode. Therefore, under a light load, the efficiency of the DC-to-DC conversion circuit is low. Summary of the invention

[0003] The present application provides a control method, a controller, a converter and a system for a DC-DC conversion circuit, which improve the efficiency of the DC-DC conversion circuit under a light load state.

[0004] In a first aspect, an embodiment of the present application provides a control method for a DC-DC conversion circuit, wherein the DC-DC conversion circuit includes a transformer, a switching circuit connected to a primary winding of the transformer, and a synchronous rectification circuit connected to a secondary winding of the transformer, wherein the switching circuit includes a first switch group and a second switch group capable of alternately connecting the primary winding to an input end of the DC-DC conversion circuit, wherein the synchronous rectification circuit includes a first rectifier module and a second rectifier module, wherein a first end of a load is connected to a first end of the secondary winding, a second end of the load is connected to a second end of the secondary winding via the first rectifier module, and the second end of the load is connected to a third end of the secondary winding via the second rectifier module, wherein the first rectifier module includes a first diode and a first rectifier switch arranged in parallel. The synchronous rectifier circuit comprises a first diode and a second rectifier switch tube connected in parallel, and the control method of the DC-DC conversion circuit comprises: controlling the first switch group and the second switch group to be turned on alternately; when the actual load power of the DC-DC conversion circuit is greater than the preset power, controlling the synchronous rectifier circuit to operate in a first mode, in which the first rectifier switch tube and the first switch group are turned on complementarily, and the second rectifier switch tube and the second switch group are turned on complementarily; when the actual load power of the DC-DC conversion circuit is less than or equal to the preset power, controlling the synchronous rectifier circuit to operate in a second mode, in which the first rectifier switch tube and the second switch group are turned on and off at the same time, and the second rectifier switch tube and the first switch group are turned on and off at the same time.

[0005] According to the aforementioned implementation of the first aspect of the present application, the control method of the DC-DC conversion circuit also includes: in the process of the actual load power of the DC-DC conversion circuit changing from greater than the preset power to less than or equal to the preset power, controlling the synchronous rectification circuit to change from the first mode to the second mode after a first switching stage, wherein the duration of the first switching stage is greater than or equal to the duration of a switching cycle of the switching circuit.

[0006] According to any of the aforementioned embodiments of the first aspect of the present application, the first switch group, the second switch group, the first rectifier switch tube, and the second rectifier switch tube are respectively controlled to be turned on and off by the corresponding first pulse signal, second pulse signal, third pulse signal, and fourth pulse signal, and are all set to be turned on at a high level, and the control of the synchronous rectifier circuit to change from the first mode to the second mode after the first switching stage includes: after the first switching moment of the first switching stage, the first pulse of the fourth pulse signal is set to be a first adjustment pulse, and after removing at least one adjacent pulse after the first adjustment pulse, it is changed to be synchronized with the first pulse signal, the first adjustment pulse is set to have a rising edge that is synchronized with the falling edge of the second pulse signal plus the dead time, and the falling edge is synchronized with the rising edge of the second pulse signal minus the dead time; after the first switching moment, the first complete pulse of the third pulse signal is set to be a second adjustment pulse, and after removing at least one adjacent pulse after the second adjustment pulse, it is changed to be synchronized with the second pulse signal, the second adjustment pulse is set to have a rising edge that is synchronized with the falling edge of the first pulse signal plus the dead time, and the falling edge is synchronized with the falling edge of the second pulse signal plus the dead time.

[0007] According to any of the aforementioned implementations of the first aspect of the present application, the control method of the DC-DC conversion circuit also includes: in the process of the actual load power of the DC-DC conversion circuit changing from less than or equal to the preset power to greater than the preset power, controlling the synchronous rectification circuit to change from the second mode to the first mode after a second switching stage, wherein the duration of the second switching stage is greater than or equal to the duration of a switching cycle of the switching circuit.

[0008] According to any of the aforementioned embodiments of the first aspect of the present application, the first switch group, the second switch group, the first rectifier switch tube, and the second rectifier switch tube are respectively controlled to be turned on and off by the corresponding first pulse signal, second pulse signal, third pulse signal, and fourth pulse signal, and are all set to be turned on at a high level. The control of the synchronous rectifier circuit from the second mode to the first mode after the second switching stage includes: after the second switching moment of the second switching stage, the third pulse signal is removed from the first M complete pulses and then transformed so that the first rectifier switch tube and the first switch group are complementarily turned on, M is a positive integer; after the second switching moment, the first complete pulse of the fourth pulse signal is set as the third adjustment pulse, and after the third adjustment pulse, it is transformed so that the second rectifier switch tube and the second switch group are complementarily turned on.

[0009] According to any of the aforementioned embodiments of the first aspect of the present application, the first switch group, the second switch group, the first rectifier switch tube, and the second rectifier switch tube are respectively controlled to be turned on and off by the corresponding first pulse signal, second pulse signal, third pulse signal, and fourth pulse signal, and are all set to be turned on at a high level. The control of the synchronous rectifier circuit from the second mode to the first mode after the second switching stage includes: after the second switching moment of the second switching stage, the third pulse signal is removed by the first N complete pulses and then transformed so that the first rectifier switch tube and the first switch group are complementarily turned on, N is a positive integer; after the second switching moment, the first complete pulse of the fourth pulse signal is set as the third adjustment pulse, and after the third adjustment pulse, the adjacent N-1 complete pulses are removed and then transformed so that the first rectifier switch tube and the first switch group are complementarily turned on.

[0010] According to any of the aforementioned implementations of the first aspect of the present application, the preset power is taken from 5% to 20% of the full load power.

[0011] In a second aspect, an embodiment of the present application provides a controller for a DC-DC conversion circuit, the controller comprising a memory and at least one processor, the memory being electrically connected to the at least one processor, the memory storing instructions, the at least one processor calling the instructions in the memory so that the controller executes a control method for a DC-DC conversion circuit according to any of the aforementioned embodiments of the first aspect of the present application.

[0012] In a third aspect, an embodiment of the present application provides a converter, which includes a DC-DC conversion circuit and a controller of the DC-DC conversion circuit according to any of the foregoing implementations of the second aspect of the present application.

[0013] In a fourth aspect, an embodiment of the present application provides a power supply system, which includes a converter according to any of the aforementioned embodiments of the third aspect of the present application.

[0014] According to the control method of the DC-DC conversion circuit of the embodiment of the present application, the switch circuit includes a first switch group and a second switch group capable of alternately connecting the primary winding to the input end of the DC-DC conversion circuit, and the synchronous rectification circuit includes a first rectification module and a second rectification module, wherein the first rectification module includes a first diode and a first rectification switch tube arranged in parallel, and the second rectification module includes a second diode and a second rectification switch tube arranged in parallel. When the DC-DC conversion circuit is controlled to work, the first switch group and the second switch group are alternately turned on, and when the actual load power of the DC-DC conversion circuit is greater than the preset power, that is, when the load is heavy, the synchronous rectification circuit is controlled to work in the first mode. In the first mode, the first rectification switch tube and the first switch group are complementary turned on, and the second rectification switch tube and the second switch group are complementary turned on. At this time, the first rectification switch tube and the second rectification switch tube participate in rectification, and the conduction loss of the first rectification switch tube and the second rectification switch tube is low, so that the DC-DC conversion circuit can be ensured to have a higher efficiency when the load is heavy. When the actual load power of the DC-DC conversion circuit is less than or equal to the preset power, that is, when the load is light, the synchronous rectification circuit is controlled to operate in the second mode. In the second mode, the first rectification switch tube and the second switch group are turned on and off at the same time, and the second rectification switch tube and the first switch group are turned on and off at the same time. Therefore, when the load is light, the first rectification switch tube and the second rectification switch tube still participate in rectification in different working modes, thereby improving the efficiency of the DC-DC conversion circuit when the load is light. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0016] Figure 1 A circuit diagram of an embodiment of a DC-DC conversion circuit of the present application;

[0017] Figure 2 This is a timing diagram of an embodiment of a control method of a DC-DC conversion circuit of the present application in a first mode;

[0018] Figure 3 This is a timing diagram of an embodiment of a control method of a DC-DC converter circuit of the present application in a second mode;

[0019] Figure 4A timing diagram of an embodiment of a control method for a DC-DC converter circuit of the present application, in which a first mode is changed to a second mode after a first switching phase;

[0020] Figure 5 A timing diagram of an embodiment of a control method for a DC-DC converter circuit of the present application, in which the second mode is changed to the first mode after a second switching phase;

[0021] Figure 6 A timing diagram of an alternative embodiment of a control method for a DC-DC converter circuit of the present application, in which the second mode is changed to the first mode after a second switching phase;

[0022] Figure 7 This is a schematic diagram of the hardware structure of an embodiment of the controller of the present application. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0024] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0025] In addition, the descriptions of "first", "second", etc. in this application are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0026] An embodiment of the present application provides a control method for a direct current-to-direct current (DC-DC) conversion circuit. Figure 1This is a circuit diagram of an embodiment of a DC-DC conversion circuit of the present application. The DC-DC conversion circuit includes a transformer 110, a switch circuit 120 connected to the primary winding Np of the transformer 110, and a synchronous rectification circuit 130 connected to the secondary winding Ns of the transformer 110. The switch circuit 120 includes a first switch group G1 and a second switch group G2 that can alternately connect the primary winding Np to the input terminal Vin of the DC-DC conversion circuit. The synchronous rectification circuit 130 includes a first rectifier module 131 and a second rectifier module 132. The first end of the load Rload is connected to the first end P1 of the secondary winding Ns, the second end of the load Rload is connected to the second end P2 of the secondary winding Ns through the first rectifier module 131, and the second end of the load Rload is connected to the third end P3 of the secondary winding Ns through the second rectifier module 132. The first rectifier module 131 includes a first diode D1 and a first rectifier switch tube Q5 that are arranged in parallel. The second rectifier module 132 includes a second diode D2 and a second rectifier switch Q6 which are connected in parallel.

[0027] The first switch group G1, the second switch group G2, the first rectifier switch tube Q5, and the second rectifier switch tube Q6 are respectively controlled to be turned on and off by the corresponding first pulse signal, second pulse signal, third pulse signal, and fourth pulse signal, and the first pulse signal, the second pulse signal, the third pulse signal, and the fourth pulse signal are pulse width modulation (PWM) signals.

[0028] The first switch group G1 and the second switch group G2 of the switch circuit 120 are connected to form a full-bridge inverter circuit. In this embodiment, the first switch group G1 includes a first switch tube Q1 and a fourth switch tube Q4 that are turned on and off together, and the second switch group G2 includes a second switch tube Q2 and a third switch tube Q3 that are turned on and off together. In some embodiments, the first switch tube Q1, the fourth switch tube Q4, the second switch tube Q2, and the third switch tube Q3 are metal-oxide-semiconductor field-effect transistors (MOSFETs).

[0029] The first diode D1 and the second diode D2 are Schottky diodes. In some embodiments, the first rectifier switch tube Q5 and the second rectifier switch tube Q6 are MOSFETs. The on-resistance of MOSFET is much smaller than the forward voltage drop of Schottky diodes, so using MOSFETs for rectification helps improve efficiency.

[0030] In some embodiments, the input terminal Vin of the DC-DC converter circuit includes an input positive electrode and an input negative electrode. In some embodiments, the DC-DC converter circuit further includes a first capacitor C1, and the first capacitor C1 is connected between the input positive electrode and the input negative electrode. In some embodiments, the DC-DC converter circuit further includes a second capacitor C2, and the second capacitor C2 is connected between one end of the primary winding Np and the switch circuit 120.

[0031] The first end of the load Rload is, for example, the output positive electrode of the output terminal Vout of the DC-DC conversion circuit, and the second end of the load Rload is, for example, the output negative electrode of the output terminal Vout of the DC-DC conversion circuit. In some embodiments, the DC-DC conversion circuit further includes a first inductor L1 and a third capacitor C3, the first inductor L1 is connected between the first end of the load Rload and the first end of the secondary winding Ns, and the third capacitor C3 is connected between the first end of the load Rload and the second end of the load Rload.

[0032] In this embodiment, the control method of the DC-DC conversion circuit includes: controlling the first switch group G1 and the second switch group G2 to be turned on alternately; when the actual load power of the DC-DC conversion circuit is greater than the preset power, controlling the synchronous rectification circuit 130 to operate in the first mode, Figure 2 This is a timing diagram of an embodiment of a control method for a DC-DC converter circuit of the present application in a first mode. In the first mode, the first rectifier switch tube Q5 and the first switch group G1 are complementary turned on, and the second rectifier switch tube Q6 and the second switch group G2 are complementary turned on; when the actual load power of the DC-DC converter circuit is less than or equal to the preset power, the synchronous rectifier circuit 130 is controlled to operate in the second mode. Figure 3 This is a timing diagram of an embodiment of the control method of the DC-DC conversion circuit of the present application in the second mode. In the second mode, the first rectifier switch tube Q5 and the second switch group G2 are turned on and off at the same time, and the second rectifier switch tube Q6 and the first switch group G1 are turned on and off at the same time. The first mode can also be called a complementary mode, and the second mode can also be called a co-on and co-off mode.

[0033] According to the control method of the DC-DC conversion circuit of the embodiment of the present application, the switch circuit 120 includes a first switch group G1 and a second switch group G2 that can alternately connect the primary winding Np to the input terminal Vin of the DC-DC conversion circuit, and the synchronous rectification circuit 130 includes a first rectification module 131 and a second rectification module 132, wherein the first rectification module 131 includes a first diode D1 and a first rectification switch tube Q5 arranged in parallel, and the second rectification module 132 includes a second diode D2 and a second rectification switch tube Q6 arranged in parallel. When the DC-DC conversion circuit is controlled to work, the first switch group G1 and the second switch group G2 are alternately turned on, and when the actual load power of the DC-DC conversion circuit is greater than the preset power, that is, when the load is heavy, the synchronous rectification circuit 130 is controlled to work in the first mode. In the first mode, the first rectifier switch tube Q5 and the first switch group G1 are complementary turned on, and the second rectifier switch tube Q6 and the second switch group G2 are complementary turned on. At this time, the first rectifier switch tube Q5 and the second rectifier switch tube Q6 participate in the rectification, and the conduction loss of the first rectifier switch tube Q5 and the second rectifier switch tube Q6 is low, so that the DC-DC conversion circuit can be guaranteed to have a higher efficiency when the load is heavy. When the actual load power of the DC-DC conversion circuit is less than or equal to the preset power, that is, when the load is light, the synchronous rectification circuit 130 is controlled to work in the second mode. In the second mode, the first rectifier switch tube Q5 and the second switch group G2 are turned on and off at the same time, and the second rectifier switch tube Q6 and the first switch group G1 are turned on and off at the same time. Therefore, when the load is light, the first rectifier switch tube Q5 and the second rectifier switch tube Q6 still participate in the rectification in different working modes, so that the efficiency of the DC-DC conversion circuit when the load is light can be improved.

[0034] In some embodiments, the preset power is taken from 5% to 20% of the full load power. In one example, less than 10% of the full load power is defined as a light load state. When the DC-DC conversion circuit is in a non-light load state, the synchronous rectification circuit 130 is controlled to operate in the first mode. When the DC-DC conversion circuit is in a light load state, the synchronous rectification circuit 130 is controlled to operate in the second mode, thereby improving the efficiency of the DC-DC conversion circuit in the light load state.

[0035] In some embodiments, the control method of the DC-DC conversion circuit also includes: in the process of the actual load power of the DC-DC conversion circuit changing from greater than a preset power to less than or equal to a preset power, controlling the synchronous rectification circuit 130 to change from a first mode to a second mode after a first switching stage, wherein the duration of the first switching stage is greater than or equal to the duration of a switching cycle of the switching circuit 120. Figure 4This is a timing diagram of an embodiment of a control method for a DC-DC converter circuit of the present application, in which a first mode is changed to a second mode after a first switching stage. By setting the first switching stage TR1 as a transition stage from the first mode to the second mode, the voltage overshoot problem during mode switching can be alleviated to a certain extent.

[0036] In some embodiments, the first switch group G1, the second switch group G2, the first rectifier switch tube Q5, and the second rectifier switch tube Q6 are respectively turned on and off by the corresponding first pulse signal X1, the second pulse signal X2, the third pulse signal X3, and the fourth pulse signal X4. The first switch group G1, the second switch group G2, the first rectifier switch tube Q5, and the second rectifier switch tube Q6 are all set to be turned on at a high level.

[0037] like Figure 4 In some embodiments, controlling the synchronous rectification circuit 130 to change from the first mode to the second mode after the first switching stage TR1 specifically includes: after the first switching moment t10 of the first switching stage TR1, setting the first pulse of the fourth pulse signal X4 to the first adjustment pulse tx1, and after removing at least one adjacent pulse after the first adjustment pulse tx1, changing to be synchronized with the first pulse signal X1, the first adjustment pulse tx1 is set to synchronize the rising edge with the falling edge of the second pulse signal X2 plus the dead time, and the falling edge is synchronized with the rising edge of the second pulse signal X2 minus the dead time; after the first switching moment t10, setting the first complete pulse of the third pulse signal X3 to the second adjustment pulse tx2, and after removing at least one adjacent pulse after the second adjustment pulse tx2, changing to be synchronized with the second pulse signal X2, the second adjustment pulse tx2 is set to synchronize the rising edge with the falling edge of the first pulse signal X1 plus the dead time, and the falling edge is synchronized with the falling edge of the second pulse signal X2 plus the dead time. Figure 4 In the figure, the pulses removed from each pulse signal are shown by dotted lines. In the embodiment, the pulses shown by dotted lines do not actually exist.

[0038] The first switching time t10 may be after the falling edge of a preset pulse of the second pulse signal X2 during the first switching phase TR1, and before the rising edge of a pulse of the first pulse signal X1 immediately following the preset pulse. Figure 4 In this embodiment, the first switching time t10 is, for example: when entering the first switching stage TR1, the falling edge of a preset pulse of the second pulse signal X2 plus the dead time.

[0039] like Figure 4In one example, after the first switching moment t10 of the first switching stage TR1, the fourth pulse signal X4 is transformed into synchronization with the first pulse signal X1 after removing one or two adjacent pulses after the first adjustment pulse tx1; after the first switching moment t10, the third pulse signal X3 is transformed into synchronization with the second pulse signal X2 after removing one adjacent pulse after the second adjustment pulse tx2.

[0040] By removing a certain amount of pulses from the fourth pulse signal X4 and the third pulse signal X3 in the first switching stage TR1 , the risk of primary side short circuit caused by simultaneous conduction of the primary side and the secondary side can be reduced.

[0041] In some embodiments, the control method of the DC-DC conversion circuit also includes: in the process of the actual load power of the DC-DC conversion circuit changing from less than or equal to the preset power to greater than the preset power, controlling the synchronous rectification circuit 130 to change from the second mode to the first mode after the second switching stage TR2, wherein the duration of the second switching stage TR2 is greater than or equal to the duration of a switching cycle of the switching circuit 120.

[0042] Figure 5 This is a timing diagram of an embodiment of a control method for a DC-DC converter circuit of the present application, in which the second mode is changed to the first mode after the second switching stage. By setting the second switching stage TR2 as a transition stage from the second mode to the first mode, the voltage overshoot problem during mode switching can be alleviated to a certain extent.

[0043] In some embodiments, the first switch group G1, the second switch group G2, the first rectifier switch tube Q5, and the second rectifier switch tube Q6 are respectively controlled to be turned on and off by the corresponding first pulse signal X1, the second pulse signal X2, the third pulse signal X3, and the fourth pulse signal X4, and are all set to be turned on at a high level.

[0044] like Figure 5 In some embodiments, controlling the synchronous rectification circuit 130 to change from the second mode to the first mode after the second switching stage TR2 includes: after the second switching time t20 of the second switching stage TR2, removing the first M complete pulses from the third pulse signal X3 and changing it to make the first rectification switch tube Q5 and the first switch group G1 complementary conduction, M is a positive integer; after the second switching time t20, setting the first complete pulse of the fourth pulse signal X4 as the third adjustment pulse, and changing it after the third adjustment pulse to make the second rectification switch tube Q6 and the second switch group G2 complementary conduction. The third adjustment pulse is kept synchronized with the first pulse signal. Figure 5 In the figure, the pulses removed from each pulse signal are shown by dotted lines. In the embodiment, the pulses shown by dotted lines do not actually exist.

[0045] The second switching time t20 may be after the falling edge of a preset pulse of the second pulse signal X2 and before the rising edge of a pulse of the first pulse signal X1 immediately following the preset pulse in the second switching stage TR2. Figure 5 In this embodiment, the second switching time t20 is, for example: when entering the second switching stage TR2, the falling edge of a preset pulse of the second pulse signal X2 plus the dead time.

[0046] like Figure 5 In one example, after the second switching time t20 of the second switching stage TR2, the third pulse signal X3 is removed from the first complete pulse and transformed to make the first rectifier switch tube Q5 and the first switch group G1 complementary turned on.

[0047] Figure 6 The timing diagram of an alternative embodiment of the control method of the DC-DC conversion circuit of the present application is a timing diagram of the transition from the second mode to the first mode after the second switching stage. The first switch group G1, the second switch group G2, the first rectifier switch tube Q5, and the second rectifier switch tube Q6 are respectively controlled to be turned on and off by the corresponding first pulse signal X1, the second pulse signal X2, the third pulse signal X3, and the fourth pulse signal X4, and are all set to be turned on at a high level.

[0048] like Figure 6 In some alternative embodiments, controlling the synchronous rectification circuit 130 to change from the second mode to the first mode after the second switching stage TR2 includes: after the second switching time t20 of the second switching stage TR2, removing the first N complete pulses from the third pulse signal X3 and changing it to make the first rectification switch tube Q5 and the first switch group G1 complementary conduction, N is a positive integer; after the second switching time t20, setting the first complete pulse of the fourth pulse signal X4 as the third adjustment pulse, and removing the adjacent N-1 complete pulses after the third adjustment pulse and changing it to make the first rectification switch tube Q5 and the first switch group G1 complementary conduction. The third adjustment pulse is kept synchronized with the first pulse signal. Figure 6 In the figure, the pulses removed from each pulse signal are shown by dotted lines. In the embodiment, the pulses shown by dotted lines do not actually exist.

[0049] The second switching moment t20 in the alternative embodiment may be set in the same manner as the second switching moment t20 in the previous embodiment.

[0050] like Figure 6In one example, N is 3. After the second switching time t20 of the second switching stage TR2, the third pulse signal X3 is removed from the first three complete pulses to make the first rectifier switch tube Q5 and the first switch group G1 complementary to each other; after the second switching time t20, the first complete pulse of the fourth pulse signal X4 is set as the third adjustment pulse, and after the third adjustment pulse, two adjacent complete pulses are removed to make the first rectifier switch tube Q5 and the first switch group G1 complementary to each other.

[0051] In some embodiments, in the first switching stage TR1, the third pulse signal X3 and / or the fourth pulse signal X4 are processed by removing a number of pulses, and in the second switching stage TR2, the third pulse signal X3 and / or the fourth pulse signal X4 are also processed by removing a number of pulses. Optionally, the number of pulses removed from the third pulse signal X3 and / or the fourth pulse signal X4 in the first switching stage TR1 can be similar to or equal to the number of pulses removed from the third pulse signal X3 and / or the fourth pulse signal X4 in the second switching stage TR2, so that the transition process of switching from the first mode to the second mode is more logically matched with the transition process of switching from the second mode to the first mode.

[0052] The embodiment of the present application also provides a controller for a DC-DC conversion circuit. Figure 7 The hardware structure diagram of an embodiment of the controller of the present application is shown in FIG. The controller includes a memory 710 and at least one processor 720, the memory 710 is electrically connected to the at least one processor 720, the memory 710 stores instructions, and the at least one processor 720 calls the instructions in the memory 710, so that the controller executes the control method of the DC-DC conversion circuit according to any of the aforementioned embodiments of the present application.

[0053] The DC-DC conversion circuit includes a transformer, a switch circuit connected to the primary winding of the transformer, and a synchronous rectification circuit connected to the secondary winding of the transformer. The switch circuit includes a first switch group G1 and a second switch group G2 that can alternately connect the primary winding to the input end of the DC-DC conversion circuit. The synchronous rectification circuit includes a first rectification module and a second rectification module. The first end of the load is connected to the first end of the secondary winding, the second end of the load is connected to the second end of the secondary winding through the first rectification module, and the second end of the load is connected to the third end of the secondary winding through the second rectification module. The first rectification module includes a first diode and a first rectification switch tube arranged in parallel. The second rectification module includes a second diode and a second rectification switch tube arranged in parallel.

[0054] The control method of the DC-DC conversion circuit includes: controlling the first switch group G1 and the second switch group G2 to be turned on alternately; when the actual load power of the DC-DC conversion circuit is greater than the preset power, controlling the synchronous rectification circuit to work in a first mode, in which the first rectification switch tube and the first switch group G1 are complementarily turned on, and the second rectification switch tube and the second switch group G2 are complementarily turned on; when the actual load power of the DC-DC conversion circuit is less than or equal to the preset power, controlling the synchronous rectification circuit to work in a second mode, in which the first rectification switch tube and the second switch group G2 are turned on and off at the same time, and the second rectification switch tube and the first switch group G1 are turned on and off at the same time.

[0055] Specifically, the processor 720 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0056] The memory 710 may include a large capacity memory 710 for data or instructions. By way of example and not limitation, the memory 710 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 710 may include a removable or non-removable (or fixed) medium. Where appropriate, the memory 710 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, the memory 710 is a non-volatile solid-state memory. In a specific embodiment, the memory 710 includes a read-only memory (ROM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically rewritable ROM (EAROM), or a flash memory, or a combination of two or more of these.

[0057] In one example, the control device may further include a communication interface 730 and a bus 740. The processor 720, the memory 710, and the communication interface 730 are connected via the bus 740 and communicate with each other.

[0058] The communication interface 730 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0059] Bus 740 includes hardware, software or both, and the parts of online data flow billing equipment are coupled to each other. For example, but not limitation, bus may include accelerated graphics port (AGP) or other graphics bus, enhanced industrial standard architecture (EISA) bus, front-end bus (FSB), hypertransport (HT) interconnection, industrial standard architecture (ISA) bus, infinite bandwidth interconnection, low pin count (LPC) bus, memory 710 bus, micro channel architecture (MCA) bus, peripheral component interconnection (PCI) bus, PCI-Express (PCI-X) bus, serial advanced technology attachment (SATA) bus, video electronics standard association local (VLB) bus or other suitable bus or two or more of these combinations. In appropriate cases, bus 740 may include one or more buses. Although the present application embodiment describes and shows a specific bus, the application considers any suitable bus or interconnection.

[0060] In addition, in combination with the control method of the DC-DC conversion circuit in the above embodiment, the embodiment of the present application can provide a power supply system to implement. The power supply system stores instructions, and when the instructions are executed by the processor, the control method of the DC-DC conversion circuit in any of the above embodiments is implemented.

[0061] The control method of the DC-DC conversion circuit includes: controlling the first switch group G1 and the second switch group G2 to be alternately turned on; when the actual load power of the DC-DC conversion circuit is greater than a preset power, controlling the synchronous rectification circuit to operate in a first mode, in which the first rectification switch tube and the first switch group G1 are complementarily turned on, and the second rectification switch tube and the second switch group G2 are complementarily turned on; when the actual load power of the DC-DC conversion circuit is less than or equal to the preset power, controlling the synchronous rectification circuit to operate in a second mode, in which the first rectification switch tube and the second switch group G2 are turned on and off at the same time, and the second rectification switch tube and the first switch group G1 are turned on and off at the same time.

[0062] The embodiment of the present application further provides a converter, which includes a DC-DC conversion circuit and a controller of the DC-DC conversion circuit of any of the above embodiments. The controller can implement the control method of the DC-DC conversion circuit of any of the above embodiments.

[0063] An embodiment of the present application also provides a power supply system, which includes a converter according to any of the aforementioned embodiments.

[0064] According to the converter and power supply system of the embodiments of the present application, a specific control method is used to enable the synchronous rectification circuit to switch between the first mode and the second mode under different actual load powers. When the load is light, the first rectification switch tube and the second rectification switch tube still participate in rectification in different working modes, thereby improving the efficiency when the load is light.

[0065] The present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known methods is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0066] The functional blocks shown in the above block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0067] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0068] The above is only a specific implementation of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this application.

Claims

1. A control method for a DC-DC conversion circuit, characterized in that: The DC-DC conversion circuit includes a transformer, a switch circuit connected to the primary winding of the transformer, and a synchronous rectification circuit connected to the secondary winding of the transformer. The switch circuit includes a first switch group and a second switch group capable of alternately connecting the primary winding to the input end of the DC-DC conversion circuit. The synchronous rectification circuit includes a first rectification module and a second rectification module. The first end of the load is connected to the first end of the secondary winding, the second end of the load is connected to the second end of the secondary winding through the first rectification module, and the second end of the load is connected to the third end of the secondary winding through the second rectification module. The first rectification module includes a first diode and a first rectification switch tube arranged in parallel, and the second rectification module includes a second diode and a second rectification switch tube arranged in parallel. The control method of the DC-DC conversion circuit comprises: Controlling the first switch group and the second switch group to be turned on alternately; When the actual load power of the DC-DC conversion circuit is greater than the preset power, the synchronous rectification circuit is controlled to operate in a first mode, in which the first rectification switch tube and the first switch group are complementary turned on, and the second rectification switch tube and the second switch group are complementary turned on; When the actual load power of the DC-DC conversion circuit is less than or equal to the preset power, the synchronous rectification circuit is controlled to operate in a second mode. In the second mode, the first rectification switch tube and the second switch group are turned on and off at the same time, and the second rectification switch tube and the first switch group are turned on and off at the same time.

2. The control method of the DC-DC conversion circuit according to claim 1, characterized in that: Also includes: In the process of the actual load power of the DC-DC conversion circuit changing from greater than the preset power to less than or equal to the preset power, the synchronous rectification circuit is controlled to change from the first mode to the second mode after a first switching stage, wherein the duration of the first switching stage is greater than or equal to the duration of one switching cycle of the switching circuit.

3. The control method of the DC-DC conversion circuit according to claim 2, characterized in that: The first switch group, the second switch group, the first rectifier switch tube, and the second rectifier switch tube are respectively controlled to be turned on and off by the corresponding first pulse signal, second pulse signal, third pulse signal, and fourth pulse signal, and are all set to be turned on at a high level. The controlling the synchronous rectification circuit to change from the first mode to the second mode after a first switching phase comprises: After the first switching moment of the first switching stage, the first pulse of the fourth pulse signal is set as the first adjustment pulse, and after removing at least one adjacent pulse after the first adjustment pulse, it is transformed into synchronization with the first pulse signal, and the first adjustment pulse is set to synchronize the rising edge with the falling edge of the second pulse signal plus the dead time, and the falling edge is synchronized with the rising edge of the second pulse signal minus the dead time; After the first switching moment, the first complete pulse of the third pulse signal is set as the second adjustment pulse, and after removing at least one adjacent pulse after the second adjustment pulse, it is transformed into synchronization with the second pulse signal, and the second adjustment pulse is set so that the rising edge is synchronized with the falling edge of the first pulse signal plus the dead time, and the falling edge is synchronized with the falling edge of the second pulse signal plus the dead time.

4. The control method of the DC-DC conversion circuit according to claim 1, characterized in that: Also includes: In the process of the actual load power of the DC-DC conversion circuit changing from less than or equal to the preset power to greater than the preset power, the synchronous rectification circuit is controlled to change from the second mode to the first mode after a second switching stage, wherein the duration of the second switching stage is greater than or equal to the duration of one switching cycle of the switching circuit.

5. The control method of the DC-DC conversion circuit according to claim 4, characterized in that: The first switch group, the second switch group, the first rectifier switch tube, and the second rectifier switch tube are respectively controlled to be turned on and off by the corresponding first pulse signal, second pulse signal, third pulse signal, and fourth pulse signal, and are all set to be turned on at a high level. The controlling the synchronous rectification circuit to change from the second mode to the first mode after a second switching phase comprises: After the second switching moment of the second switching stage, the third pulse signal is transformed after removing the first M complete pulses so as to make the first rectifier switch tube and the first switch group complementary turned on, where M is a positive integer; After the second switching moment, the first complete pulse of the fourth pulse signal is set as the third adjustment pulse, and after the third adjustment pulse, the second rectifying switch tube and the second switch group are turned on complementarily.

6. The control method of the DC-DC conversion circuit according to claim 4, characterized in that: The first switch group, the second switch group, the first rectifier switch tube, and the second rectifier switch tube are respectively controlled to be turned on and off by the corresponding first pulse signal, second pulse signal, third pulse signal, and fourth pulse signal, and are all set to be turned on at a high level. The controlling the synchronous rectification circuit to change from the second mode to the first mode after a second switching phase comprises: After the second switching moment of the second switching stage, the third pulse signal is transformed after removing the first N complete pulses so as to make the first rectifier switch tube and the first switch group complementary turned on, where N is a positive integer; After the second switching moment, the first complete pulse of the fourth pulse signal is set as the third adjustment pulse, and after removing adjacent N-1 complete pulses after the third adjustment pulse, the first rectifier switch tube and the first switch group are turned on complementarily.

7. The control method of the DC-DC converter circuit according to any one of claims 1 to 6, characterized in that: The preset power is 5% to 20% of the full load power.

8. A controller for a DC-DC conversion circuit, characterized in that: The controller includes a memory and at least one processor, the memory is electrically connected to the at least one processor, and instructions are stored in the memory. The at least one processor calls the instruction in the memory so that the controller executes the control method of the DC-DC conversion circuit according to any one of claims 1 to 7.

9. A converter, characterized in that: The invention comprises a DC-DC conversion circuit and a controller of the DC-DC conversion circuit as claimed in claim 8.

10. A power supply system, characterized in that: Comprising a converter as claimed in claim 9.

Images