Energy recovery circuit and electrical device

Abstract

Provided in the embodiments of the present application is an energy recovery circuit. The energy recovery circuit comprises a front-end energy storage circuit, a switching circuit, a controller, a transformer, an energy absorption circuit, an energy transfer circuit and an energy control circuit, wherein when the switching circuit enters a turned-off state, the energy absorption circuit absorbs a current flowing through a primary coil of the transformer and stores same, and the energy control circuit controls the energy transfer circuit to transfer energy absorbed by the energy absorption circuit to the front-end energy storage circuit, which stores same. Therefore, in the energy recovery circuit, when a switching circuit enters a turned-off state, an energy absorption circuit can prevent a spike voltage generated on the switching circuit by a current flowing through a primary coil, so as to implement high-voltage protection on the switching circuit. In addition, the energy recovery circuit further uses an energy transfer circuit to transfer energy absorbed by the energy absorption circuit to a front-end energy storage circuit, such that the recovered energy continues to be transferred to a secondary coil, thereby improving the conversion efficiency of a power supply.

Description

An energy recovery circuit and electrical device

[0001] This application claims priority to Chinese Patent Application No. 2024116659722, filed on November 20, 2024, entitled "An Energy Recovery Circuit and Electrical Equipment", the entire contents of which are incorporated herein by reference.

[0002] Technical Field

[0003] This application relates to the field of switching power supply technology, and in particular to an energy recovery circuit and electrical equipment. Background Technology

[0004] When the main switch in a switching power supply enters the off state, it is subjected to a high-voltage surge, which can damage the main switch. To prevent this damage, a snubber network is typically used in switching power supplies to clamp the switching voltage of the main switch, suppressing the switching voltage and providing high-voltage protection.

[0005] While absorption networks can provide high-voltage protection for the main switching transistor, they also dissipate the absorbed energy, resulting in high energy loss and low energy conversion efficiency in the switching power supply. Furthermore, the energy consumed by the absorption network causes a significant temperature rise inside the switching power supply, accelerating the aging of components and reducing the reliability and lifespan of the entire system. Summary of the Invention

[0006] This application provides an energy recovery circuit and electrical device that can improve power conversion efficiency.

[0007] In a first aspect, embodiments of this application provide an energy recovery circuit, including:

[0008] A front-end energy storage circuit is configured to store energy, the front-end energy storage circuit including a first node;

[0009] Switching circuit, including the second node;

[0010] The controller, electrically connected to the switching circuit, is configured to control the switching circuit to enter an on or off state.

[0011] A transformer includes a coupled primary coil and a secondary coil, the primary coil being electrically connected between a first node and a second node, the primary coil being configured to transfer energy to the secondary coil based on the current output by the front-end energy storage circuit in response to the switching circuit entering an on or off state.

[0012] An energy absorption circuit, electrically connected to the second node, is configured to absorb and store the current flowing through the primary coil in response to the switching circuit entering the off state. The energy absorption circuit includes a third node.

[0013] An energy transfer circuit is electrically connected to the third node and also electrically connected to the front-end energy storage circuit.

[0014] An energy control circuit, electrically connected to the energy transfer circuit, is configured to control the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit to the front-end energy storage circuit for storage.

[0015] In some embodiments, the energy control circuit is configured to control the energy transfer circuit to adjust the energy absorption circuit to a regulated state, so that the voltage across the primary coil is regulated after the switching circuit is turned off, and the current flowing through the primary coil decreases uniformly.

[0016] In some embodiments of this application, the energy control circuit includes:

[0017] A voltage regulation control circuit, electrically connected to the energy absorption circuit and the energy transfer circuit respectively, is configured to control the energy transfer circuit to adjust the energy absorption circuit to a voltage regulation state, so that the voltage across the primary coil is in a voltage regulation state after the switching circuit is turned off, and the current flowing through the primary coil decreases uniformly.

[0018] A delay circuit, electrically connected to the voltage regulator control circuit, is configured to control the response of the voltage regulator control circuit to lag behind the change in voltage across the energy absorption circuit.

[0019] In some embodiments of this application, the voltage regulation control circuit includes:

[0020] A voltage detection circuit, electrically connected to the energy absorption circuit and the delay circuit respectively, is configured to detect the voltage across the energy absorption circuit to obtain a sampled voltage, wherein the delay circuit is configured to control the sampled voltage to lag behind the change in the voltage across the energy absorption circuit.

[0021] A voltage monitoring circuit, electrically connected to both the voltage detection circuit and the energy transfer circuit, is configured to control the operating state of the energy transfer circuit based on the sampled voltage.

[0022] In some embodiments of this application, the voltage detection circuit is electrically connected between the first node and the third node, and is configured to detect the voltage across the energy absorption circuit, obtain a sampled voltage, and transmit the sampled voltage to the voltage monitoring circuit.

[0023] In some embodiments of this application, the voltage detection circuit includes a first resistor and a second resistor, one end of the first resistor is electrically connected to the third node, the other end of the first resistor and one end of the second resistor are electrically connected to the fourth node, the voltage monitoring circuit is electrically connected to the fourth node, and the other end of the second resistor is electrically connected to the first node.

[0024] In some embodiments of this application, the voltage detection circuit includes: a first voltage sampling branch, a second voltage sampling branch, and an operational amplifier;

[0025] A first voltage sampling branch is electrically connected between the first node and ground. The first voltage sampling branch includes a fifth node, and the inverting input terminal of the operational amplifier is electrically connected to the fifth node. The first voltage sampling branch is configured to detect the voltage at the first node to obtain a first sampling voltage.

[0026] The second voltage sampling branch is electrically connected between the third node and the ground terminal. The second voltage sampling branch includes a sixth node. The non-inverting input terminal of the operational amplifier is electrically connected to the sixth node. The output terminal of the operational amplifier is electrically connected to the voltage monitoring circuit. The second voltage sampling branch is configured to detect the voltage at the third node to obtain a second sampling voltage.

[0027] The operational amplifier is configured to perform signal conditioning processing on the first sampled voltage and the second sampled voltage to obtain a conditioned sampled voltage.

[0028] In some embodiments of this application, the transformer further includes an auxiliary coil coupled to the primary coil;

[0029] The voltage detection circuit also includes a power input circuit, which is electrically connected to the auxiliary coil and the operational amplifier, and is configured to provide operating power to the operational amplifier.

[0030] In some embodiments of this application, the voltage monitoring circuit is configured to control the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit in response to the sampling voltage being greater than a preset reference voltage; or...

[0031] The voltage monitoring circuit is configured to control the energy transfer circuit to stop transferring the energy absorbed by the energy absorption circuit in response to the sampling voltage being less than or equal to a preset reference voltage.

[0032] In some embodiments of this application, the delay circuit includes a delay capacitor electrically connected to the input node between the voltage detection circuit and the voltage monitoring circuit.

[0033] In some embodiments of this application, the energy transfer circuit includes:

[0034] An energy processing circuit is electrically connected to the energy absorption circuit and the front-end energy storage circuit, respectively.

[0035] The transfer control circuit, electrically connected to both the energy control circuit and the energy processing circuit, is configured to, in response to a first start signal transmitted by the energy control circuit, control the energy processing circuit to receive energy released by the energy absorption circuit, or, in response to a first stop signal transmitted by the energy control circuit, control the energy processing circuit to stop receiving energy released by the energy absorption circuit. In the stopped state, the energy processing circuit transmits the received energy back to the front-end energy storage circuit for storage.

[0036] In some embodiments of this application, the energy processing circuit includes:

[0037] The energy transfer unit is electrically connected to the front-end energy storage circuit;

[0038] The first switching unit, electrically connected to both the energy absorption circuit and the transfer control circuit, is configured to either enter a conducting state in response to a second start signal transmitted by the transfer control circuit, allowing the energy released by the energy absorption circuit to flow through the first switching unit to the energy storage transfer unit for storage, or enter a turning-off state in response to a second stop signal transmitted by the transfer control circuit, preventing the energy released by the energy absorption circuit from flowing through the first switching unit to the energy storage transfer unit for storage, and causing the energy storage transfer unit to transfer the stored energy to the front-end energy storage circuit.

[0039] In some embodiments of this application, the first switching unit includes a first switching transistor, which is electrically connected to the energy absorption circuit, the transfer control circuit, and the energy storage transfer unit, and is configured to enter a conduction state in response to the second start signal, or to enter a shutdown state in response to the second stop signal.

[0040] In some embodiments of this application, the energy storage transfer unit includes:

[0041] An energy storage inductor, one end of which is electrically connected to the first switching unit, and the other end of which is electrically connected to the front-end energy storage circuit;

[0042] A first unidirectional conduction circuit is provided, with one end of the first unidirectional conduction circuit electrically connected to one end of the energy storage inductor, and the other end of the first unidirectional conduction circuit being grounded together with the ground terminal of the front-end energy storage circuit. The first unidirectional conduction circuit is configured such that when the first switching unit enters the off state, the current flowing through the energy storage inductor can flow back to the front-end energy storage circuit through the first unidirectional conduction circuit.

[0043] In some embodiments of this application, the transfer control circuit includes:

[0044] The second switching unit is electrically connected to the energy control circuit and is configured to enter the on state in response to the first start signal, or to enter the off state in response to the first stop signal.

[0045] The voltage divider unit is electrically connected to the third node, the energy processing circuit, and the second switching unit, respectively. It is configured to convert the voltage at the third node into a second start signal in response to the second switching unit entering the on state, so that the energy processing circuit can receive the energy released by the energy absorption circuit in response to the second start signal; or, in response to the second switching unit entering the off state, convert the voltage across the energy absorption circuit into a second stop signal, so that the energy processing circuit can stop receiving the energy released by the energy absorption circuit in response to the second stop signal.

[0046] In some embodiments of this application, the second switching unit includes a second switching transistor, which is electrically connected to the energy control circuit and the voltage divider unit respectively, and is configured to enter a conducting state in response to the first start signal, or to enter a turning-off state in response to the first stop signal.

[0047] In some embodiments of this application, the energy absorption circuit includes:

[0048] Absorption unit;

[0049] A second unidirectional conduction circuit is electrically connected between the second node and the third node. The second unidirectional conduction circuit is configured such that when the switching circuit enters the off state, the current flowing through the primary coil can flow back to the absorption unit for storage.

[0050] In some embodiments of this application, the absorption unit is electrically connected between the first node and the third node; or,

[0051] The absorption unit is electrically connected between the third node and the ground terminal.

[0052] In some embodiments of this application, the absorption unit is a first capacitor.

[0053] In some embodiments of this application, the front-end energy storage circuit is a second capacitor, one end of which is electrically connected to the first node, and the other end of which is grounded.

[0054] In some embodiments of this application, the switching circuit includes a main switching transistor, which is electrically connected to the primary coil and also to the controller, and is configured to enter a conducting state in response to a conduction signal sent by the controller, or to enter a turning-off state in response to a turning-off signal sent by the controller.

[0055] In some embodiments of this application, the transformer operates in flyback mode or forward mode.

[0056] Secondly, embodiments of this application provide an electrical device including the energy recovery circuit described above.

[0057] Compared to existing technologies, the energy recovery circuit in this application includes a front-end energy storage circuit, a switching circuit, a controller, a transformer, an energy absorption circuit, an energy transfer circuit, and an energy control circuit. The controller controls the switching circuit to enter an on or off state. The primary coil responds to the switching circuit's on or off state, transferring energy to the secondary coil based on the current output from the front-end energy storage circuit. When the switching circuit is off, the energy absorption circuit absorbs and stores the current flowing through the primary coil. The energy control circuit also controls the energy transfer circuit to transfer the energy released by the energy absorption circuit, transferring the received energy to the front-end energy storage circuit for storage, thus completing energy recovery. Therefore, when the switching circuit is off, the energy absorption circuit can absorb the voltage spikes formed on the switching circuit by the current flowing through the primary coil, providing high-voltage protection for the switching circuit. Furthermore, the energy recovery circuit uses an energy transfer circuit to transfer the energy absorbed by the energy absorption circuit to the front-end energy storage circuit for storage, allowing the recovered energy to continue to be transferred to the secondary coil, improving power conversion efficiency. Attached Figure Description

[0058] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0059] Figure 1 is a schematic diagram of one of the power supply systems provided in an embodiment of this application;

[0060] Figure 2 is a schematic diagram of one type of energy recovery circuit provided in an embodiment of this application;

[0061] Figure 3 is a schematic diagram of one type of energy absorption circuit provided in an embodiment of this application;

[0062] Figure 4 is a schematic diagram of one type of energy control circuit provided in an embodiment of this application;

[0063] Figure 5 is a schematic diagram of one type of energy control circuit provided in an embodiment of this application;

[0064] Figure 6 is a schematic diagram of one type of energy control circuit provided in an embodiment of this application;

[0065] Figure 7 is a schematic diagram of one type of energy transfer circuit provided in an embodiment of this application;

[0066] Figure 8 is a schematic diagram of one type of energy transfer circuit provided in an embodiment of this application;

[0067] Figure 9 is a schematic diagram of one type of energy transfer circuit provided in an embodiment of this application;

[0068] Figure 10 is a schematic diagram of the circuit structure of one of the energy recovery circuits provided in the embodiments of this application;

[0069] Figure 11 is a schematic diagram of the circuit structure of one of the energy recovery circuits provided in the embodiments of this application;

[0070] Figure 12 is a schematic diagram of the circuit structure of one of the energy recovery circuits provided in the embodiments of this application;

[0071] Figure 13 is a schematic diagram of the circuit structure of one of the energy recovery circuits provided in the embodiments of this application.

[0072] Embodiments of the present invention

[0073] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0074] In this application, when an element is described as "connected" to another element, it can be directly connected to the other element, or there may be one or more intermediate elements between them.

[0075] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0076] Please refer to Figure 1, which is a schematic diagram of the structure of an electrical device provided in an embodiment of this application. As shown in Figure 1, the electrical device includes an energy recovery circuit 100, a power supply 200, and a load 300.

[0077] The power supply 200 is connected to the energy recovery circuit 100 and provides power to the energy recovery circuit 100. The power supply 200 can be a DC power supply or an AC power supply. When the power supply 200 is an AC power supply, it provides DC power to the energy recovery circuit 100 after rectification and filtering. Furthermore, the power supply 200 can be a power supply circuit composed of any suitable discrete components. For example, in some embodiments, the power supply 200 is a power supply circuit composed of a filter circuit, a rectifier circuit, and a voltage regulator circuit. In other embodiments, the power supply 200 is an integrated power chip.

[0078] The energy recovery circuit 100 processes the power supplied by the power supply 200 to obtain a secondary voltage signal. The voltage of this secondary voltage signal is the output voltage, which can be a high voltage signal or a safe voltage, such as 24V or 36V.

[0079] The energy recovery circuit 100 is connected to the load 300 and provides an output voltage to the load 300. The load 300 implements the corresponding load control logic according to the drive of the secondary voltage signal.

[0080] As shown in Figure 2, the energy recovery circuit 100 includes a front-end energy storage circuit 1, a switching circuit 2, a controller 3, an energy absorption circuit 4, a transformer 5, an energy transfer circuit 6, and an energy control circuit 7. The transformer 5 includes a coupled primary coil L1 and a secondary coil L2. The grounding terminal is point a. The front-end energy storage circuit 1 includes a first node point b, and the switching circuit includes a second node point c. The primary coil L1 is electrically connected between the first node point b and the second node point c. The switching circuit 2 is electrically connected to the second node point c. The energy absorption circuit 4 is also electrically connected between the first node point b and the second node point c. The switching circuit 2 is also electrically connected to the controller 3. The energy transfer circuit 6 is electrically connected to the third node point d of the energy absorption circuit 4. The energy transfer circuit 6 is also electrically connected to the front-end energy storage circuit 1 at the first node point b. The energy control circuit 7 is electrically connected to the energy transfer circuit 6.

[0081] The front-end energy storage circuit 1 stores energy, specifically the electrical energy of the power supply 200. The controller 3 controls the switching circuit 2 to enter the on or off state. The working state of the switching circuit 2 controls the energy coupling between the primary coil L1 and the secondary coil L2. The energy on the front-end energy storage circuit 1 is converted into a secondary isolated power supply through the coupling of the primary coil L1 and the secondary coil L2, which is applied to the load 300.

[0082] Specifically, if the energy recovery circuit 100 is a forward switching power supply, the controller 3 controls the switching circuit 2 to enter the conducting state, and the current output by the front-end energy storage circuit 1 flows through the primary coil L1. Through the alternating conversion of the electromagnetic field, the electrical energy flowing through the primary coil L1 is coupled to the secondary coil L2. The secondary coil L2 generates an induced voltage to transfer energy to the load circuit.

[0083] When controller 3 controls switch circuit 2 to enter the off state, the current in primary coil L1 cannot instantly return to zero; it undergoes a process of decreasing from its maximum to zero. Because the current in primary coil L1 is suddenly cut off, the abrupt change in current causes a voltage spike across primary coil L1. Therefore, at the instant switch circuit 2 is turned off, the voltage across switch circuit 2 is the sum of a transient spike voltage and the voltage across primary coil L1. Simultaneously, after switch circuit 2 is turned off, a portion of the energy corresponding to the freewheeling current in primary coil L1 needs to be processed, such as being absorbed or dissipated.

[0084] If the energy recovery circuit 100 is a flyback switching power supply, then the controller 3 controls the switching circuit 2 to enter the conducting state. The current output from the front-end energy storage circuit 1 flows through the primary coil L1, storing energy in the primary coil L1. The controller 3 then controls the switching circuit 2 to enter the off state, and the energy stored in the primary coil L1 is coupled to the secondary coil L2 to transfer energy to the secondary coil L2. Similar to a forward switching power supply, at the instant the switching circuit 2 is turned off, the voltage across the switching circuit 2 is the sum of a transient spike voltage and the voltage of the primary coil L1. Simultaneously, after the switching circuit 2 is turned off, a portion of the energy corresponding to the freewheeling current of the primary coil L1 needs to be processed, such as being absorbed or consumed.

[0085] In some embodiments, the controller 3 is a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a microcontroller, an ARM (Acorn RISC Machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or a combination of these components.

[0086] To prevent the switching circuit 2 from being impacted by the transient voltage spike after it is turned off, and to effectively utilize the energy contained in the freewheeling current, the energy recovery circuit 100 also includes an energy absorption circuit 4, which is electrically connected between the second node c and the first node b, or electrically connected between the second node c and ground a. The energy absorption circuit 4 absorbs and stores the freewheeling current flowing through the primary coil L1 and the energy it contains, and clamps the voltage that the switching circuit 2 experiences after it is turned off, thereby protecting the switching circuit 2. The energy absorption circuit 4 consists of a unidirectional conducting circuit and a capacitor of microfarad level or above.

[0087] Please refer to Figure 2. When the switching circuit 2 enters the off state, the energy absorption circuit 4 absorbs the current flowing through the primary coil L1 and the energy it contains for storage, thus obtaining the first energy. At the same time, it prevents the switching circuit 2 from being impacted by a spike high voltage at the moment of off, thus protecting the switching circuit 2.

[0088] In order to make full use of the energy absorbed by the energy absorption circuit, the energy control circuit 7 controls the energy transfer circuit 6 to transfer the energy absorbed by the energy absorption circuit 4 to the front-end energy storage circuit 1 for storage.

[0089] Specifically, as the first energy stored in the energy absorption circuit 4 increases, when the energy control circuit 7 detects that the first energy stored in the energy absorption circuit 4 is greater than the preset energy, the energy control circuit 7 sends a first start signal to control the energy transfer circuit 6 to receive and store the energy released by the energy absorption circuit 4.

[0090] As the energy absorption circuit 4 releases more and more first energy, when the energy control circuit 7 detects that the remaining first energy of the energy absorption circuit 4 is less than the preset energy, the energy control circuit 7 sends a first stop signal to control the energy transfer circuit 6 to stop receiving the energy released by the energy absorption circuit 4, and the energy absorption circuit 4 can no longer release energy to the energy transfer circuit 6 through the third node d.

[0091] Simultaneously, the energy transfer circuit 6 transmits the received energy back to the front-end energy storage circuit 1 for storage. For example, if the first energy is E1 and the recovered energy is the second energy E2, then the energy transfer circuit 6 transfers the second energy E2 to the front-end energy storage circuit 1 for storage, and the difference between the first energy E1 and the second energy E2 is the remaining energy of the energy absorption circuit 4.

[0092] The front-end energy storage circuit 1 stores the second energy E2. When the switching circuit 2 enters the next on or off state, the front-end energy storage circuit 1 continues to transfer the second energy E2 through the coupling between the primary coil L1 and the secondary coil L2 to the secondary coil L2, thereby supplying power to the load 300.

[0093] Therefore, in this embodiment, the energy absorption circuit 4 absorbs the voltage spikes formed on the switching circuit 2 by the current flowing through the primary coil L1, providing high-voltage protection for the switching circuit 2. Furthermore, the energy absorbed by the energy absorption circuit 4 is not consumed; instead, the energy transfer circuit 6 receives the energy released by the energy absorption circuit 4 and transmits it back to the front-end energy storage circuit 1. This allows the recovered energy to continue to be transferred to the secondary coil L2 via coupling, thus achieving reuse and improving the power conversion efficiency. Consequently, the system temperature rise is low, and the system reliability is improved.

[0094] In some embodiments, as shown in FIG3, the energy absorption circuit 4 includes an absorption unit 42 and a second unidirectional conduction circuit 41, wherein the second unidirectional conduction circuit 41 is electrically connected between the second node c and the third node d, and the absorption unit 42 is electrically connected between the first node b and the third node d, or the absorption unit 42 is electrically connected between the third node d and the ground terminal. FIG4 shows an example where the absorption unit 42 is electrically connected between the third node d and the first node b.

[0095] When the switching circuit 2 enters the off state, the primary coil L1, the second unidirectional conduction circuit 41 and the absorption unit 42 form a loop. The current flowing through the primary coil L1 flows back to the absorption unit 42 through the second unidirectional conduction circuit 41 for storage. The current direction is: primary coil L1 → second unidirectional conduction circuit 41 → absorption unit 42.

[0096] The second unidirectional conduction circuit 41 can be implemented by means of synchronous rectification circuit, diode, field effect transistor and unidirectional conduction thyristor, etc. The absorption unit 42 is a circuit that can store energy, which can be implemented by means of capacitor, battery, etc.

[0097] In some embodiments, as shown in FIG4, the energy control circuit 7 includes a voltage regulation control circuit 71, wherein the voltage regulation control circuit 71 is electrically connected to the energy absorption circuit 4 and the energy transfer circuit 6 respectively.

[0098] When the voltage regulator control circuit 71 detects that the first energy of the energy absorption circuit 4 is greater than the preset energy, the voltage regulator control circuit 71 sends a first start signal to control the energy transfer circuit 6 to transfer the energy absorbed by the energy absorption circuit 4 to the front-end energy storage circuit 1. As the transfer occurs, the energy of the energy absorption circuit 4 will decrease. When the voltage regulator control circuit 71 detects that the remaining first energy of the energy absorption circuit 4 is less than the preset energy, the voltage regulator control circuit 71 sends a first stop signal to control the energy transfer circuit 6 to stop transferring the energy absorbed by the energy absorption circuit 4.

[0099] Therefore, the energy transfer circuit 6 can control the energy of the energy absorption circuit 4, keeping it in a small fluctuation range, so that the voltage across its terminals is equivalent to a stable voltage. After the switching circuit 2 is turned off, the voltage across the primary coil L1 is the same as the voltage across the energy absorption circuit 4, which is equivalent to the voltage across the primary coil L1 being in a stable voltage state. This causes the current flowing through the primary coil L1 to decrease uniformly, and the magnetic flux in the transformer 5 to change uniformly, thereby keeping the output voltage at the secondary coil L2 stable.

[0100] The voltage at the third node d reflects the voltage across the energy absorption circuit 4 in real time. Therefore, in this embodiment, a voltage detection circuit is used to detect the voltage at the third node d.

[0101] Specifically, as shown in Figure 4, the voltage regulation control circuit 71 includes a voltage detection circuit 711 and a voltage monitoring circuit 712. The voltage detection circuit 711 is electrically connected to the energy absorption circuit 4, and the voltage monitoring circuit 712 is electrically connected to the voltage detection circuit 711 and the energy transfer circuit 6, respectively.

[0102] The voltage detection circuit 711 is electrically connected between the third node d and the first node b. The voltage detection circuit 711 detects the voltage across the energy absorption circuit 4 to obtain a sampled voltage, and transmits the sampled voltage to the voltage monitoring circuit 712. The voltage monitoring circuit 712 controls the operating state of the energy transfer circuit 6 based on the sampled voltage.

[0103] As the energy absorption circuit 4 absorbs more and more energy, the voltage across the circuit increases, and consequently, the sampling voltage increases. When the sampling voltage exceeds a preset reference voltage, the voltage monitoring circuit 712 controls the energy transfer circuit 6 to begin recovering and transferring the energy absorbed by the energy absorption circuit 4. The sampling voltage signal exceeding the preset reference voltage is the first trigger signal in the above embodiment.

[0104] As energy is transferred, the energy in the energy absorption circuit 4 decreases, and consequently, the voltage across the energy absorption circuit 4 decreases. When the sampled voltage is less than or equal to a preset reference voltage, the voltage monitoring circuit 712 controls the energy transfer circuit 6 to stop transferring the energy released by the energy absorption circuit 4. The sampled voltage signal that is less than or equal to the preset reference voltage is the second trigger signal in the above embodiment.

[0105] Therefore, in this embodiment, the voltage detection circuit 711 monitors the voltage across the energy absorption circuit 4 in real time to control the energy of the energy absorption circuit 4. When the voltage across the energy absorption circuit 4 is high, the voltage monitoring circuit 712 controls the energy transfer circuit 6 to transfer the energy of the energy absorption circuit 4. The voltage detection circuit 711 and the voltage monitoring circuit 712 can effectively control the energy transfer process of the energy transfer circuit 6.

[0106] In the above embodiment, when the voltage across the energy absorption circuit 4 changes, the sampling voltage reflects the change in voltage across the energy absorption circuit 4 in real time. The sampling voltage follows the increase or decrease of the voltage across the energy absorption circuit 4 in real time, so the voltage monitoring circuit 712 responds in real time to the increase or decrease of the sampling voltage and controls the energy transfer circuit 6 to enter the working state or enter the stopped working state.

[0107] However, this might cause the operating state of the energy transfer circuit 6 to change too frequently. For example, if the voltage across the energy absorption circuit 4 is V1, the sampled voltage is greater than the preset reference voltage, but the difference between the sampled voltage and the preset reference voltage is small, it is enough to keep the energy transfer circuit 6 in operation, allowing it to normally recover energy from the energy absorption circuit 4. When the voltage across the energy absorption circuit 4 changes slightly, dropping to V2, the sampled voltage reflects this slight change in real time. This slight change causes the sampled voltage to be less than the preset reference voltage, triggering the voltage monitoring circuit 712 and thus controlling the energy transfer circuit 6 to enter a stopped operating state. Similarly, if the voltage across the energy absorption circuit 4 changes slightly again, rising to V3, this slight change is again reflected in the sampled voltage in real time. If this causes the sampled voltage to be greater than the preset reference voltage again, the voltage monitoring circuit 712 is triggered, thus controlling the energy transfer circuit 6 to re-enter the operating state.

[0108] If the sampled voltage responds to the voltage across the energy transfer circuit 6 in real time, it may cause the voltage monitoring circuit 712 to be frequently triggered and the operating state of the energy transfer circuit 6 to be frequently changed. This may result in frequent responses to some false triggering events, as well as increased wear and tear on the voltage monitoring circuit 712 and the energy transfer circuit 6, and may even lead to increased component temperature or damage.

[0109] For the reasons mentioned above, please refer to Figure 4. In this embodiment, the energy control circuit 7 further includes a delay circuit 72, wherein the delay circuit 72 is electrically connected to the input node between the voltage detection circuit 711 and the voltage monitoring circuit 712. The delay circuit 72 controls the sampling voltage to lag behind the change in the voltage across the energy absorption circuit 4.

[0110] In this embodiment, a delay circuit 72 is used to control the sampling voltage to lag behind the change in voltage across the energy absorption circuit 4. When the voltage across the energy absorption circuit 4 changes between V1 and V2, or between V2 and V3, the sampling voltage change lags behind, thereby reducing the frequent triggering of the voltage monitoring circuit 712 and the energy transfer circuit 6, preventing false triggering, and improving the reliability and stability of the system.

[0111] The delay circuit 72 can be implemented in various ways, such as an RC delay circuit, a 555 timer delay circuit, a monostable multivibrator delay circuit, a transistor delay circuit, an oscillator counter delay circuit, etc.

[0112] In some embodiments, as shown in FIG5, the voltage detection circuit 711 further includes a voltage sampling circuit 7111 and a signal conditioning circuit 7112, wherein the voltage sampling circuit 7111 is electrically connected to the energy absorption circuit 4, and the signal conditioning circuit 7112 is electrically connected to the voltage sampling circuit 7111 and the voltage monitoring circuit 712, respectively.

[0113] In this embodiment, the first terminal of the voltage sampling circuit 7111 is electrically connected to the third node d, the second terminal is electrically connected to the first node b, and the third terminal is grounded. The output terminal of the voltage sampling circuit 7111 is also electrically connected to the input terminal of the signal conditioning circuit 7112, and the output terminal of the signal conditioning circuit 7112 is electrically connected to the voltage monitoring circuit 712.

[0114] The voltage sampling circuit 7111 detects the voltage across the energy absorption circuit 4 to obtain a sampled voltage. The sampled voltage is transmitted to the input of the signal conditioning circuit 7112. The signal conditioning circuit 7112 performs signal conditioning processing on the sampled voltage to obtain a conditioned sampled voltage, so that the voltage monitoring circuit 712 controls the working state of the energy transfer circuit 6 based on the conditioned sampled voltage.

[0115] The voltage sampling circuit 7111 can be implemented in various ways, such as through a resistor divider network or a dedicated sampling element. The signal conditioning circuit 7112 can amplify, filter, or isolate the sampled voltage, making the conditioned sampled voltage more stable and accurate, and facilitating the voltage monitoring circuit 712 to respond to the conditioned sampled voltage.

[0116] In some embodiments, the signal conditioning circuit 7112 requires a power supply to operate normally. This power supply can be a separate, independent power source, such as a separate power module or battery, independent of other parts of the system. Such a power supply can provide stable voltage and current. Alternatively, the power supply can be directly coupled from the primary coil L1, which reduces the need for an external power source, simplifies circuit design, and reduces circuit cost.

[0117] In this embodiment, the working power supply is coupled from the primary coil L1. Specifically, as shown in FIG5, the transformer 5 also includes an auxiliary coil L4, which is coupled to the primary coil L1.

[0118] When the switching circuit 2 is in the on state, current flows through the primary coil L1, and the primary coil L1 generates a magnetic field. Part of the energy of the primary coil L1 is transferred to the auxiliary coil L4 through coupling, and a coupling voltage is generated on the auxiliary coil L4. The value of the coupling voltage is determined by the turns ratio of the auxiliary coil L4 to the primary coil L1, and the turns ratio of the auxiliary coil L4 to the primary coil L1 is determined based on the operating power supply of the signal conditioning circuit 7112.

[0119] In some embodiments, the coupling voltage does not directly supply power to the signal conditioning circuit 7112. The coupling voltage needs to be conditioned and the conditioned coupling voltage is used as the operating power supply of the signal conditioning circuit 7112.

[0120] Specifically, the voltage detection circuit 711 also includes a power input circuit 7113, which is electrically connected to both the auxiliary coil L4 and the signal conditioning circuit 7112. The power input circuit 7113 provides operating power to the signal conditioning circuit 7112 based on the coupled voltage. The power input circuit 7113 performs voltage regulation, filtering, and noise reduction on the coupled voltage, and uses the processed coupled voltage as the operating power supply for the signal conditioning circuit 7112. The power processing circuit regulates the coupled voltage, reducing voltage fluctuations, and reduces noise, making the conditioned coupled voltage more stable and reliable.

[0121] In some embodiments, referring to FIG6, the signal conditioning circuit 7112 is an operational amplifier op1, and the voltage sampling circuit 7111 includes a first voltage sampling branch 71111 and a second voltage sampling branch 71112. The first voltage sampling branch 71111 is electrically connected between a first node (b) and ground, and includes a fifth node. The inverting input of operational amplifier op1 is electrically connected to the fifth node. The second voltage sampling branch 71112 is electrically connected between a third node (d) and ground, and includes a sixth node. The non-inverting input of operational amplifier op1 is electrically connected to the sixth node, and the output of operational amplifier op1 is electrically connected to the voltage monitoring circuit 712.

[0122] The first voltage sampling branch 71111 is connected to the first node b at one end, which is the second end of the voltage sampling circuit 7111. The second voltage sampling branch 71112 is connected to the third node d at one end, which is the first end of the voltage sampling circuit 7111. The common grounding terminal of the first voltage sampling branch 71111 and the second voltage sampling branch 71112 is the third end of the voltage sampling circuit 7111.

[0123] The first voltage sampling branch 71111 samples the voltage at the first node b to obtain the first sampled voltage. The second voltage sampling branch 71112 samples the voltage at the third node d to obtain the second sampled voltage. The operational amplifier op1 differentially amplifies the first sampled voltage and the second sampled voltage to obtain the conditioned sampled voltage. The voltage monitoring circuit 712 controls the working state of the energy transfer circuit 6 based on the conditioned sampled voltage.

[0124] The first voltage sampling branch 71111 and the second voltage sampling branch 71112 are used to sample the voltage at the first node b and the third node d, respectively. The conditioned sampled voltage reflects the change in the voltage difference between the first node b and the third node d. The conditioned sampled voltage is obtained by differential amplification, which can eliminate common-mode interference in the first and second sampled voltages, such as noise or electromagnetic interference in the environment, thereby improving the signal-to-noise ratio. It can also enhance the difference between the first and second sampled voltages, more accurately measure the voltage difference between the two nodes, and thus improve the accuracy of the sampled voltage.

[0125] In some embodiments, please refer to FIG7, which is a schematic diagram of the structure of an energy transfer circuit 6 provided in an embodiment of this application. As shown in FIG7, the energy transfer circuit 6 includes an energy processing circuit 61 and a transfer control circuit 62. The energy processing circuit 61 is electrically connected to the energy absorption circuit 4 and the front-end energy storage circuit 1, respectively, and the transfer control circuit 62 is electrically connected to the energy control circuit 7 and the energy processing circuit 61, respectively.

[0126] Specifically, the energy processing circuit 61 is electrically connected to the third node d, the front-end energy storage circuit 1, and the transfer control circuit 62. When the switching circuit 2 enters the off state, the energy absorption circuit 4 absorbs and stores the current flowing through the primary coil L1. When the energy control circuit 7 detects that the first energy absorbed by the energy absorption circuit 4 is greater than the preset energy, the energy control circuit 7 transmits a first start signal to the transfer control circuit 62. The transfer control circuit 62 responds to the first start signal and controls the energy processing circuit 61 to transfer the energy absorbed by the energy absorption circuit 4. The energy of the energy absorption circuit 4 is transferred to the energy processing circuit 61 via the third node d.

[0127] As the energy absorption circuit 4 releases energy, when the energy control circuit 7 detects that the first energy absorbed by the energy absorption circuit 4 is less than or equal to the preset energy, the energy control circuit 7 transmits a first stop signal to the transfer control circuit 62, controlling the energy processing circuit 61 to stop receiving the energy released by the energy absorption circuit 4, and to send the received energy back to the front-end energy storage circuit 1 for storage.

[0128] The energy processing circuit 61 recovers the energy released by the energy absorption circuit 4. This recovery can be achieved through storage; that is, the energy processing circuit 61 stores the energy released by the energy absorption circuit 4 and, in a stopped state, transmits the stored energy back to the front-end energy storage circuit 1, so that the front-end energy storage circuit 1 stores the transmitted energy. For example, if the energy released by the energy absorption circuit 4 is a second energy E2, the energy processing circuit 61 first receives and stores this second energy E2. In a stopped state, it then transmits the second energy E2 back to the front-end energy storage circuit 1, which then stores the second energy E2. Through this two-stage transfer and storage, the second energy E2 is ultimately recovered and returned to the front-end energy storage circuit 1.

[0129] In some embodiments, referring to FIG8, the energy processing circuit 61 includes an energy storage and transfer unit 611 and a first switching unit 612. The energy storage and transfer unit 611 is electrically connected to the front-end energy storage circuit 1, and the first switching unit 612 is electrically connected to the energy absorption circuit 4 and the transfer control circuit 62, respectively. Specifically, the first switching unit 612 is electrically connected to the third node d and the transfer control circuit 62, and the energy storage and transfer unit 611 is electrically connected to the front-end energy storage circuit 1.

[0130] When the transfer control circuit 62 responds to the first start signal, it transmits a second start signal to the first switching unit 612. The first switching unit 612 enters the on state, and the energy released by the energy absorption circuit 4 flows to the energy storage transfer unit 611 via the third node d and the first switching unit 612. The energy storage transfer unit 611 stores the released energy. When the transfer control circuit 62 responds to the first stop signal, it transmits a second stop signal to the first switching unit 612. The first switching unit 612 enters the off state, thereby blocking the energy released by the energy absorption circuit 4 from flowing to the energy storage transfer unit 611 via the third node d and the first switching unit 612. That is, the energy absorption circuit 4 can no longer release energy to the energy storage transfer unit 611 via the third node d and the first switching unit 612, or it cannot transfer energy to the energy storage transfer unit 611, or the energy released by the energy absorption circuit 4 can no longer flow to the energy storage transfer unit 611. Furthermore, after the first switching unit 612 enters the off state, the energy stored in the energy transfer unit 611 is returned to the front-end energy storage circuit 1.

[0131] Therefore, in this embodiment, the energy control circuit 7 sends a first start signal or a first stop signal, and then sends a second start signal or a second stop signal to the control transfer control circuit 62 to control the working state of the first switching unit 612, and then controls the energy storage transfer unit 611 to recover or store the energy released by the energy absorption circuit 4.

[0132] Furthermore, in this embodiment, the energy storage transfer unit 611 stores the energy released by the energy absorption circuit 4, and then transmits the stored energy back to the front-end energy storage circuit 1, so that the energy released by the energy absorption circuit 4 is transferred and stored twice, thereby realizing energy recovery.

[0133] In some embodiments, please continue referring to Figure 8. The energy storage transfer unit 611 includes an energy storage inductor 6111 and a first unidirectional conduction circuit 6112. One end of the energy storage inductor 6111 is electrically connected to the first switching unit 612, and the other end of the energy storage inductor 6111 is electrically connected to the front-end energy storage circuit 1. One end of the first unidirectional conduction circuit 6112 is electrically connected to one end of the energy storage inductor 6111, and the other end of the first unidirectional conduction circuit 6112 is grounded together with the ground terminal of the front-end energy storage circuit 1. The first unidirectional conduction circuit 6112 can be implemented by means of a synchronous rectifier circuit, a diode, a field-effect transistor, or a unidirectional thyristor.

[0134] When the first switching unit 612 is in the ON state, the energy from the energy absorption circuit 4 flows through the third node d and the first switching unit 612 to the energy storage inductor 6111, where the energy storage inductor 6111 stores the energy released by the energy absorption circuit 4. When the first switching unit 612 is in the OFF state, the energy from the energy absorption circuit 4 stops flowing to the energy storage inductor 6111. Simultaneously, the energy stored in the energy storage inductor 6111 flows back to the front-end energy storage circuit 1 through the first unidirectional conducting circuit 6112, meaning the energy stored in the energy storage inductor 6111 is transferred back to the front-end energy storage circuit 1 for storage.

[0135] In this embodiment, the energy released by the energy absorption circuit 4 is first transferred to the energy storage inductor 6111, and then transferred to the front-end energy storage circuit 1 through the energy storage inductor 6111. The energy released by the energy absorption circuit 4 is transferred and stored twice to achieve energy recovery.

[0136] In some embodiments, as shown in FIG9, the transfer control circuit 62 includes a second switching unit 621 and a voltage divider unit 622. The second switching unit 621 is electrically connected to the energy control circuit 7, and the voltage divider unit 622 is electrically connected to the energy absorption circuit 4, the energy processing circuit 61, and the second switching unit 621, respectively. Specifically, the voltage divider unit 622 is electrically connected to the third node d, the energy processing circuit 61, and the second switching unit 621, respectively.

[0137] When the energy control circuit 7 sends the first start signal to the second switch unit 621, the second switch unit 621 is in the conducting state. The voltage divider unit 622 divides the voltage at the third node and generates a voltage divider signal, which is the second start signal. The second start signal is transmitted to the energy processing circuit 61. The energy processing circuit 61 responds to the second start signal and recovers the energy released by the energy absorption circuit 4.

[0138] When the energy control circuit 7 sends a first stop signal to the second switching unit 621, the second switching unit 621 enters the off state. The voltage divider unit 622 responds to the second switching unit 621 entering the off state and converts the voltage across the energy absorption circuit 4 into a second stop signal. The energy processing circuit 61 responds to the second stop signal and stops recovering the energy released by the energy absorption circuit 4.

[0139] In this embodiment, the energy control circuit 7 controls the working state of the second switching unit 621 through the first start signal and the first stop signal, thereby controlling the second switching unit 621 to send the second start signal or the second stop signal to the energy processing circuit 61, so as to control the energy processing circuit 61 to be in the recycling state or the recycling stop state.

[0140] Please refer to Figure 10. Figure 10 is a schematic diagram of the circuit structure of an energy recovery circuit provided in an embodiment of this application. As shown in Figure 10, transformer 5 is transformer T1, absorption unit 42 is first capacitor C2, front-end energy storage circuit 1 is second capacitor C0, one end of second capacitor C0 is electrically connected to the first node b, and the other end of second capacitor C0 is grounded. The capacitance value of first capacitor C2 is greater than or equal to the microfarad level.

[0141] The second unidirectional conduction circuit 41 is a diode D1. The anode of diode D1 is electrically connected to the second node c. The cathode of diode D1 and one end of the first capacitor C2 are electrically connected to the third node d. The other end of the first capacitor C2 is electrically connected to the first node b. One end of the first capacitor C2 can be its positive terminal, and the other end of the first capacitor C2 can be its negative terminal.

[0142] The switching circuit 2 includes a main switching transistor G1, which is a MOS transistor. The drain of the main switching transistor G1 is electrically connected to the primary coil L1 at the second node c. The gate of the main switching transistor G1 is connected to the controller 3, and the source of the main switching transistor G1 is grounded.

[0143] When controller 3 sends a turn-on signal to the gate of main switch G1, main switch G1 enters the turn-on state. When controller 3 sends a turn-off signal to the gate of main switch G1, main switch G1 enters the turn-off state. The operating state of main switch G1 controls the energy coupling between primary coil L1 and secondary coil L2.

[0144] The second capacitor C0 is used to store electrical energy from the power source. The electrical energy stored in the second capacitor C0 is transmitted to the secondary coil L2 through the coupling between the primary coil L1 and the secondary coil L2, and then supplies power to the load.

[0145] When the main switch G1 is turned off, the current flowing through the primary coil L1 is I12, and the voltage in the primary coil L1 is U12. The current I12 flowing through the primary coil L1 flows through diode D1 to the first capacitor C2. The first capacitor C2 absorbs and stores the current flowing through the primary coil L1, clamping the switching voltage of the main switch G1 to prevent it from being impacted by high voltage spikes, thus protecting the main switch G1. After the power supply is started, the first capacitor C2 continuously absorbs the energy E12 in the primary coil L1 after the main switch G1 is turned off and stores it to form energy Ec2. As the energy EC2 absorbed and stored by the first capacitor C2 increases, the voltage Udb across the first capacitor C2 increases with the increase of energy EC2.

[0146] Please refer to Figure 10. The voltage detection circuit 711 includes resistors R4 and R5. The voltage monitoring circuit 712 is a voltage monitor U1. Pin 1 of the voltage monitor U1 is node e, pin 2 of the voltage monitor U1 is node g, and pin 3 of the voltage monitor U1 is connected to node b.

[0147] The delay circuit 72 is capacitor C3. Resistors R4 and R5 are connected in series between the third node d and the first node b. The common connection terminal of resistors R4 and R5 is connected to pin 1 of voltage monitor U1 and one end of capacitor C3, respectively. The other end of capacitor C3 is connected to pin 3 of voltage monitor U1 at the first node b. Pin 2 of voltage monitor U1 is electrically connected to energy transfer circuit 6.

[0148] The first switching unit 612 includes a first switching transistor G2, the second switching unit 621 includes a second switching transistor G3, the voltage divider unit 622 includes resistors R2 and R3, the energy storage inductor 6111 is an inductor L3, and the first unidirectional conduction circuit 6112 is a diode D2.

[0149] The gate of the second switch G3 is connected to pin 2 of the voltage monitor U1. The source of the second switch G3 is connected to the first node b. Resistors R2 and R3 are connected in series between the third node d and the drain of the second switch G3. The common connection terminal of resistors R2 and R3 is node i, which is connected to the gate of the first switch G2. The source of the first switch G2 is connected to the third node d. The drain of the first switch G2 is connected to one end of inductor L3 and the cathode of diode D2 at point h. The other end of inductor L3 is connected to the first node b. The anode of diode D2 is grounded.

[0150] Resistors R4 and R5 divide the voltage across the first capacitor C2, generating a voltage Ueb at pin 1 of the voltage monitor U1. This voltage Ueb is also the voltage across capacitor C3. The voltage Ueb increases as the voltage across the first capacitor C2 increases. However, due to the delay effect of capacitor C3, the increase in voltage Ueb lags behind the increase in voltage across the first capacitor C2.

[0151] When Udb rises to equal ((R4+R5)÷R5)×Vref (threshold voltage of voltage monitor U1), Ueb is still lower than Vref. Only when Udb rises to a certain value (specifically defined here as Udb0) will Ueb rise to Vref.

[0152] When the voltage Udb across the first capacitor C2 continues to rise until the voltage Ueb equals the threshold voltage Vref of the voltage monitor U1, the voltage monitor U1 outputs a high level, that is, the voltage Ugb between node g and node b is high.

[0153] The high-level voltage Ugb drives the second switch G3 to conduct. At this time, the voltage Udb generates a voltage drop Udi across the resistor R2. Udi drives the first switch G2 to conduct. At this time, the first capacitor C2 absorbs and stores the energy Ec2, which is transferred to the inductor L3 through the first switch G2. The current in the inductor L3 (defined here as IL3) gradually increases from 0.

[0154] As energy Ec2 is transferred to inductor L3 through the first switch G2, the voltage Udb across the first capacitor C2 decreases. As Udb decreases, the voltage Ueb across capacitor C3 also decreases. However, due to the blocking effect of resistors R4 and R5, the voltage drop of Ueb across capacitor C3 lags behind the decrease of Udb across capacitor C2. When Udb decreases to equal ((R4+R5)÷R5)×Vref (threshold voltage of voltage monitor U1), Ueb is still higher than Vref. At this point, voltage monitor U1 still outputs a high level, and energy Ec2 continues to be transferred to inductor L3 through the first switch G2. Only when Udb continues to decrease below a certain value (specifically defined as Udb1) will Ueb decrease to equal Vref. As Udb continues to decrease, Ueb will decrease to slightly below Vref, voltage monitor U1 outputs a low level, meaning the voltage Ugb between node g and node b is almost zero, and the second switch G3 is turned off.

[0155] After the second switch G3 is turned off, the voltage Udb generates a voltage drop Udi across resistor R2, which is 0. The first switch G2 is turned off. At this time, the energy Ec2 stored in the first capacitor C2 stops being transferred to the inductor L3 through the first switch G2 (here, the part of the energy stored in C2 that is transferred to the inductor L3 is specifically defined as EL3). The current IL3 in the inductor L3 reaches its maximum (here, this maximum current is defined as IL31).

[0156] Due to the freewheeling characteristic of inductor L3, after the first switch G2 is turned off, the driving current IL3 of inductor L3 flows into the second capacitor C0 through the loop formed by inductor L3, diode D2, and the second capacitor C0. Before the first switch G2 is turned on again, the current IL3 drops from the maximum current IL31 to 0. At the same time, the energy EL3 transferred from the first capacitor C2 to inductor L3 is transferred to the second capacitor C0. Thus, the energy E12 formed by I12 and U12 in the primary coil L1 after the switch G1 is turned off is recovered.

[0157] The energy E12 formed by I12 and U12 in the primary coil L1 is transferred and stored in the second capacitor C0 after a second transfer, so that the recovered energy can continue to be transferred to the secondary coil L2 through coupling, thereby improving the power conversion efficiency.

[0158] In this embodiment, energy-consuming components are removed, which significantly reduces internal heat generation, temperature rise, and the impact of temperature rise on power supply components, thereby significantly improving component reliability, operating time, and overall power supply reliability.

[0159] Furthermore, due to the delay effect of capacitor C3, the change of Ueb lags behind the change of Udb. The switching control process of the voltage monitor U1 output to the second switching transistor G3 has a hysteresis process. During this hysteresis process, the voltage Udb across the first capacitor C2 fluctuates between Udb0 and Udb1, but is basically stable at the value of ((R4+R5)÷R5)×Vref.

[0160] Therefore, the voltage Udb across the first capacitor C2 is essentially in a regulated state, stable at a fixed value of ((R4+R5)÷R5)×Vref (with ripple present). This stable voltage Udb allows the current I12 in the primary winding L1 to uniformly decrease from its maximum value to 0 after the switch G1 is turned off. The voltage U12 in the primary winding L1 remains constant during this uniform decrease of current I12, and returns to 0 when current I12 reaches zero. This uniform change in current I12 in the primary winding L1 causes a uniform change in the magnetic flux in the transformer T1's magnetic circuit, thus stabilizing the output voltage of the secondary winding L2.

[0161] It should be noted that, except for the first capacitor C1 and the inductor L3, all other components in the energy absorption circuit 4, energy control circuit 7, and energy transfer circuit 6 can be integrated into a single chip, or integrated with the controller 3 to form a single chip.

[0162] Please refer to Figure 11. Figure 11 is a schematic diagram of the circuit structure of one of the energy recovery circuits provided in the embodiment of this application. As shown in Figure 11, the difference between the embodiment of this application and the embodiment shown in Figure 10 is that the negative terminal of the first capacitor C2 is grounded. The connection and working principle of other components are the same as those in the embodiment shown in Figure 11, and will not be repeated here.

[0163] Please refer to Figure 12. Figure 12 is a schematic diagram of the circuit structure of one of the energy recovery circuits provided in the embodiment of this application. As shown in Figure 12, the difference between the embodiment of this application and the embodiment shown in Figure 10 is that the resistor R3 is replaced with the voltage regulator D3. The cathode of the voltage regulator D3 is connected to node i, and the anode of the voltage regulator D3 is connected to the drain of the second switching transistor G3. The connection and working principle of other components are the same as those in the embodiment shown in Figure 11, and will not be repeated here.

[0164] In this embodiment, due to the voltage regulation effect of the voltage regulator D3, the parameter selection of resistor R2 is more flexible, and the second switch G3 obtains a more stable driving voltage.

[0165] Please refer to Figure 13. Figure 13 is a schematic diagram of the circuit structure of one of the energy recovery circuits provided in the embodiment of this application. As shown in Figure 13, the difference between the embodiment of this application and the embodiment shown in Figure 10 is that the voltage detection circuit 711 includes a voltage sampling circuit 7111 and a signal conditioning circuit 7112. The voltage sampling circuit 7111 includes a first voltage sampling branch 71111 and a second voltage sampling branch 71112.

[0166] The first voltage sampling branch 71111 includes resistors R6 and R7, the second voltage sampling branch 71112 includes resistors R4 and R5, and the signal conditioning circuit 7112 includes operational amplifier op1 and resistors R8 to R11. Resistors R4 and R5 are connected in series between the third node d and ground. One end of resistors R4, R5, capacitor C3, and resistor R10 is connected to node e. Resistors R6 and R7 are connected in series between the first node b and ground. One end of resistors R6, R7, and R9 is connected to node f. The other end of resistor R9 is connected to the inverting input of operational amplifier op1 and one end of resistor R8. The other end of resistor R10 is connected to the non-inverting input of operational amplifier op1 and one end of resistor R11. The other end of resistor R8 is connected to the output of operational amplifier op1 and pin 1 of voltage monitor U1. The other end of resistor R11 is grounded, and pin 3 of voltage monitor U1 is grounded. Furthermore, the source of the second switch G3 is no longer connected to the first node b, but is grounded.

[0167] Therefore, in this embodiment, the voltage reference point of the voltage sampling circuit 7111 is ground. Meanwhile, in this embodiment, operating power is supplied to the operational amplifier op1 via the auxiliary coil L4 and the power input circuit 7113.

[0168] Specifically, transformer T1 also includes an auxiliary coil L4, which is coupled to the primary coil L1. The power input circuit 7113 includes a Schottky diode D3, a Schottky diode D4, a capacitor C4, and a capacitor C5. One end of the auxiliary coil L4 is connected to the anode of the voltage regulator D3 and the anode of the voltage regulator D4, respectively, and the other end of the auxiliary coil L4 is grounded. The cathode of the voltage regulator D3 is connected to one end of the capacitor C4, and the other end of the capacitor C4 is grounded. The cathode of the voltage regulator D4 is connected to one end of the capacitor C5, and the other end of the capacitor C5 is grounded.

[0169] When the switching transistor G1 is in the on state, current flows through the primary coil L1, and the primary coil L1 generates a magnetic field. Part of the energy of the primary coil L1 is transferred to the auxiliary coil L4 through coupling, and a coupling voltage is generated on the auxiliary coil L4.

[0170] The coupling voltage is regulated by voltage regulators D3 and D4, and filtered by capacitors C4 and C5, and then converted into the power supply for operational amplifier op1, enabling op1 to operate normally.

[0171] Resistor R4 and resistor R5 divide the voltage at point d of the third node to obtain the first sampling voltage. Resistor R6 and resistor R7 divide the voltage at point b of the first node to obtain the second sampling voltage. Operational amplifier op1 differentially amplifies the first sampling voltage and the second sampling voltage to obtain the conditioned sampling voltage. Voltage monitor U1 controls the working state of the second switch G3 based on the conditioned sampling voltage.

[0172] The connection methods and working principles of other components are the same as those in the embodiment shown in Figure 11, and will not be repeated here.

[0173] In summary, when the switching circuit enters the off state, the energy absorption circuit can absorb the voltage spikes formed by the current flowing through the primary coil in the switching circuit, providing high-voltage protection for the switching circuit. Furthermore, the energy recovery circuit also employs an energy transfer circuit to transfer the energy released by the energy absorption circuit to the front-end energy storage circuit, allowing the recovered energy to continue to be transferred to the secondary coil, thereby improving the power conversion efficiency.

[0174] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0175] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An energy recovery circuit, characterized in that, include: A front-end energy storage circuit is configured to store energy, the front-end energy storage circuit including a first node; Switching circuit, including the second node; The controller, electrically connected to the switching circuit, is configured to control the switching circuit to enter an on or off state. A transformer includes a coupled primary coil and a secondary coil, the primary coil being electrically connected between a first node and a second node, the primary coil being configured to transfer energy to the secondary coil based on the current output by the front-end energy storage circuit in response to the switching circuit entering an on or off state. An energy absorption circuit, electrically connected to the second node, is configured to absorb and store the current flowing through the primary coil in response to the switching circuit entering the off state. The energy absorption circuit includes a third node. An energy transfer circuit is electrically connected to the third node and also electrically connected to the front-end energy storage circuit. An energy control circuit, electrically connected to the energy transfer circuit, is configured to control the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit to the front-end energy storage circuit for storage.

2. The energy recovery circuit according to claim 1, characterized in that, The energy control circuit is configured to control the energy transfer circuit to adjust the energy absorption circuit to a stable voltage state, so that the voltage across the primary coil is stable after the switching circuit is turned off, and the current flowing through the primary coil decreases uniformly.

3. The energy recovery circuit according to claim 2, characterized in that, The energy control circuit includes: A voltage regulation control circuit, electrically connected to the energy absorption circuit and the energy transfer circuit respectively, is configured to control the energy transfer circuit to adjust the energy absorption circuit to a voltage regulation state, so that the voltage across the primary coil is in a voltage regulation state after the switching circuit is turned off, and the current flowing through the primary coil decreases uniformly. A delay circuit, electrically connected to the voltage regulator control circuit, is configured to control the response of the voltage regulator control circuit to lag behind the change in voltage across the energy absorption circuit.

4. The energy recovery circuit according to claim 3, characterized in that, The voltage regulation control circuit includes: A voltage detection circuit, electrically connected to the energy absorption circuit and the delay circuit respectively, is configured to detect the voltage across the energy absorption circuit to obtain a sampled voltage, wherein the delay circuit is configured to control the sampled voltage to lag behind the change in the voltage across the energy absorption circuit. A voltage monitoring circuit, electrically connected to both the voltage detection circuit and the energy transfer circuit, is configured to control the operating state of the energy transfer circuit based on the sampled voltage.

5. The energy recovery circuit according to claim 4, characterized in that, The voltage detection circuit is electrically connected between the first node and the third node, and is configured to detect the voltage across the energy absorption circuit, obtain a sampled voltage, and transmit the sampled voltage to the voltage monitoring circuit.

6. The energy recovery circuit according to claim 5, characterized in that, The voltage detection circuit includes a first resistor and a second resistor. One end of the first resistor is electrically connected to the third node, and the other end of the first resistor and one end of the second resistor are electrically connected to the fourth node. The voltage monitoring circuit is electrically connected to the fourth node, and the other end of the second resistor is electrically connected to the first node.

7. The energy recovery circuit according to claim 4, characterized in that, The voltage detection circuit includes: a first voltage sampling branch, a second voltage sampling branch, and an operational amplifier; A first voltage sampling branch is electrically connected between the first node and ground. The first voltage sampling branch includes a fifth node, and the inverting input terminal of the operational amplifier is electrically connected to the fifth node. The first voltage sampling branch is configured to detect the voltage at the first node to obtain a first sampling voltage. The second voltage sampling branch is electrically connected between the third node and the ground terminal. The second voltage sampling branch includes a sixth node. The non-inverting input terminal of the operational amplifier is electrically connected to the sixth node. The output terminal of the operational amplifier is electrically connected to the voltage monitoring circuit. The second voltage sampling branch is configured to detect the voltage at the third node to obtain a second sampling voltage. The operational amplifier is configured to perform signal conditioning processing on the first sampled voltage and the second sampled voltage to obtain a conditioned sampled voltage.

8. The energy recovery circuit according to claim 7, characterized in that, The transformer also includes an auxiliary coil, which is coupled to the primary coil. The voltage detection circuit also includes a power input circuit, which is electrically connected to the auxiliary coil and the operational amplifier, and is configured to provide operating power to the operational amplifier.

9. The energy recovery circuit according to any one of claims 4 to 8, characterized in that, The voltage monitoring circuit is configured to control the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit in response to the sampling voltage being greater than a preset reference voltage; or... The voltage monitoring circuit is configured to control the energy transfer circuit to stop transferring the energy absorbed by the energy absorption circuit in response to the sampling voltage being less than or equal to a preset reference voltage.

10. The energy recovery circuit according to claim 4, characterized in that, The delay circuit includes a delay capacitor, which is electrically connected to the input node between the voltage detection circuit and the voltage monitoring circuit.

11. The energy recovery circuit according to any one of claims 1 to 8, characterized in that, The energy transfer circuit includes: An energy processing circuit is electrically connected to the energy absorption circuit and the front-end energy storage circuit, respectively. The transfer control circuit, electrically connected to both the energy control circuit and the energy processing circuit, is configured to, in response to a first start signal transmitted by the energy control circuit, control the energy processing circuit to receive energy released by the energy absorption circuit, or, in response to a first stop signal transmitted by the energy control circuit, control the energy processing circuit to stop receiving energy released by the energy absorption circuit. In the stopped state, the energy processing circuit transmits the received energy back to the front-end energy storage circuit for storage.

12. The energy recovery circuit according to claim 11, characterized in that, The energy processing circuit includes: The energy transfer unit is electrically connected to the front-end energy storage circuit; The first switching unit, electrically connected to both the energy absorption circuit and the transfer control circuit, is configured to either enter a conducting state in response to a second start signal transmitted by the transfer control circuit, allowing the energy released by the energy absorption circuit to flow through the first switching unit to the energy storage transfer unit for storage, or enter a turning-off state in response to a second stop signal transmitted by the transfer control circuit, preventing the energy released by the energy absorption circuit from flowing through the first switching unit to the energy storage transfer unit for storage, and causing the energy storage transfer unit to transfer the stored energy to the front-end energy storage circuit.

13. The energy recovery circuit according to claim 12, characterized in that, The first switching unit includes a first switching transistor, which is electrically connected to the energy absorption circuit, the transfer control circuit, and the energy storage transfer unit, and is configured to enter the on state in response to the second start signal, or to enter the off state in response to the second stop signal.

14. The energy recovery circuit according to claim 12, characterized in that, The energy storage transfer unit includes: An energy storage inductor, one end of which is electrically connected to the first switching unit, and the other end of which is electrically connected to the front-end energy storage circuit; A first unidirectional conduction circuit is provided, with one end of the first unidirectional conduction circuit electrically connected to one end of the energy storage inductor, and the other end of the first unidirectional conduction circuit being grounded together with the ground terminal of the front-end energy storage circuit. The first unidirectional conduction circuit is configured such that when the first switching unit enters the off state, the current flowing through the energy storage inductor can flow back to the front-end energy storage circuit through the first unidirectional conduction circuit.

15. The energy recovery circuit according to claim 11, characterized in that, The transfer control circuit includes: The second switching unit is electrically connected to the energy control circuit and is configured to enter the on state in response to the first start signal, or to enter the off state in response to the first stop signal. The voltage divider unit is electrically connected to the third node, the energy processing circuit, and the second switching unit, respectively. It is configured to convert the voltage at the third node into a second start signal in response to the second switching unit entering the on state, so that the energy processing circuit can receive the energy released by the energy absorption circuit in response to the second start signal; or, in response to the second switching unit entering the off state, convert the voltage across the energy absorption circuit into a second stop signal, so that the energy processing circuit can stop receiving the energy released by the energy absorption circuit in response to the second stop signal.

16. The energy recovery circuit according to claim 15, characterized in that, The second switching unit includes a second switching transistor, which is electrically connected to the energy control circuit and the voltage divider unit, respectively, and is configured to enter a conducting state in response to the first start signal, or to enter a turning-off state in response to the first stop signal.

17. The energy recovery circuit according to any one of claims 1 to 8, characterized in that, The energy absorption circuit includes: Absorption unit; A second unidirectional conduction circuit is electrically connected between the second node and the third node. The second unidirectional conduction circuit is configured such that when the switching circuit enters the off state, the current flowing through the primary coil can flow back to the absorption unit for storage.

18. The energy recovery circuit according to claim 17, characterized in that, The absorption unit is electrically connected between the first node and the third node; or... The absorption unit is electrically connected between the third node and the ground terminal.

19. The energy recovery circuit according to claim 17, characterized in that, The absorption unit is the first capacitor.

20. The energy recovery circuit according to any one of claims 1 to 8, characterized in that, The front-end energy storage circuit is a second capacitor, one end of which is electrically connected to the first node, and the other end of which is grounded.

21. The energy recovery circuit according to any one of claims 1 to 8, characterized in that, The switching circuit includes a main switching transistor, which is electrically connected to the primary coil and also to the controller. It is configured to enter a conducting state in response to a conduction signal sent by the controller, or to enter a turning-off state in response to a turning-off signal sent by the controller.

22. The energy recovery circuit according to any one of claims 1 to 8, characterized in that, The transformer operates in either flyback mode or forward mode.

23. An electrical device, characterized in that, Includes the energy recovery circuit as described in any one of claims 1 to 22.

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