Interleaved flyback power supply circuit, switching power supply and power supply equipment
By designing an alternating flyback power supply circuit, the problem of low transformer utilization is solved by using the first and second transformers to alternately output voltage, thereby increasing output power and reducing costs.
Patent Information
- Application Number
- CN202520282869.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-20
- Publication Date
- 2025-12-30
- Estimated Expiration
- 2035-02-20
AI Technical Summary
The utilization rate of transformers in existing switching power supplies is low, resulting in low output power.
An alternating flyback power supply circuit is adopted, which combines a first transformer and a second transformer, a voltage sampling circuit, an alternating flyback power supply chip and a switching circuit to achieve alternating output voltage of the transformer and improve transformer utilization.
This improved the utilization rate and output power of the transformer, reduced the output ripple current, extended the life of the electrolytic capacitor, and reduced the cost of the capacitor.
Smart Images
Figure CN223744575U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of switching power supplies, and more particularly to an interleaved flyback power supply circuit, a switching power supply, and a power supply device. Background Technology
[0002] Switching power supplies are indispensable power electronic devices in modern society, widely used in electronics, communications, electrical engineering, energy, lighting, and home appliances. With the further development of power electronics technology, the requirements for switching power supplies in terms of size, reliability, cost, energy efficiency, and environmental friendliness are increasing. Currently, switching power supplies generally adopt forward, flyback, and push-pull topologies. Among them, the flyback topology is widely used in low-to-medium power switching power supplies due to its simple structure, ability to achieve input-output isolation, and power factor correction function. However, switching power supplies using a single transformer in a flyback topology have low transformer utilization and low output power. Summary of the Invention
[0003] In view of the shortcomings of the prior art, the purpose of this utility model is to provide an interleaved flyback power supply circuit, a switching power supply, and a power supply device to solve the problem of low output power of the transformer in the switching power supply.
[0004] The technical solution of this utility model is as follows:
[0005] This utility model provides an interleaved flyback power supply circuit, including:
[0006] First transformer;
[0007] Second transformer;
[0008] A voltage sampling circuit is electrically connected to the first transformer and the second transformer. The voltage sampling circuit is used to collect the operating voltage of the first transformer and the second transformer and output a voltage sampling signal.
[0009] An interleaved flyback power supply chip is connected to the output terminal of the voltage sampling circuit. The interleaved flyback power supply chip is used to alternately output a first drive signal and a second drive signal according to the voltage sampling signal.
[0010] A switching circuit is connected in series between the interleaved flyback power supply chip and the first transformer and the second transformer. The switching circuit is used to turn on or off the electrical connection between the interleaved flyback power supply chip and the first transformer according to a first drive signal, and to turn on or off the electrical connection between the interleaved flyback power supply chip and the second transformer according to a second drive signal.
[0011] Optionally, the interleaved flyback power supply chip includes:
[0012] The signal receiving pin is connected to the output terminal of the voltage sampling circuit.
[0013] A drive signal controller is connected to the signal receiving pin, and the drive signal controller is used to output a first drive control signal and a second drive control signal according to the voltage sampling signal;
[0014] A first driving circuit is connected to the driving signal controller, and the first driving circuit is used to output a first driving signal according to the first driving control signal.
[0015] A second driving circuit is connected to the driving signal controller, and the second driving circuit is used to output a second driving signal according to the second driving control signal.
[0016] The first signal output pin is connected to the output terminal of the first driving circuit and is also electrically connected to the switching circuit. The first driving circuit outputs the first driving signal to the switching circuit through the first signal output pin.
[0017] The second signal output pin is connected to the output terminal of the second driving circuit and is also electrically connected to the switching circuit. The second driving circuit outputs the second driving signal to the switching circuit through the second signal output pin.
[0018] Optionally, the interleaved flyback power supply chip further includes:
[0019] An over / under voltage detection circuit is used to detect the input voltage of the interleaved flyback power supply chip and output an over / under voltage detection signal.
[0020] An over-temperature detection circuit is used to detect the temperature of the interleaved flyback power supply chip and output a temperature detection signal;
[0021] A logic controller is connected to the output terminals of the over / under voltage detection circuit and the over-temperature detection circuit, and also to the input terminals of the first driving circuit and the second driving circuit. The logic controller is used to control the alternating operation logic of the first driving circuit and the second driving circuit according to the over / under voltage detection signal and the temperature detection signal.
[0022] Power input terminal, used to connect to an external power source;
[0023] A voltage clamping circuit is disposed between the power input terminal and the first driving circuit and the second driving circuit. The voltage clamping circuit is used to clamp the external power supply and output it to the first driving circuit and the second driving circuit.
[0024] Optionally, the switching circuit includes a first resistor, a second resistor, a first MOSFET, and a second MOSFET. The first end of the first resistor is connected to the first signal output pin, the second end of the first resistor is connected to the gate of the first MOSFET, the source of the first MOSFET is connected to the ground pin of the interleaved flyback power supply chip, and the drain of the first MOSFET is connected to the first transformer. The first end of the second resistor is connected to the second signal output pin, the second end of the second resistor is connected to the gate of the second MOSFET, the source of the second MOSFET is connected to the ground pin of the interleaved flyback power supply chip, and the drain of the second MOSFET is connected to the second transformer.
[0025] Optionally, the voltage sampling circuit includes:
[0026] The secondary-side sampling circuit is connected to the secondary windings of the first transformer and the second transformer, and is also connected to the sampling input terminal of the interleaved flyback power supply chip. The secondary-side sampling circuit is used to sample the voltage of the secondary windings of the first transformer and the second transformer, and output the corresponding voltage sampling signal to the interleaved flyback power supply chip.
[0027] Optionally, the voltage sampling circuit includes:
[0028] The primary-side sampling circuit is connected to the primary windings of the first transformer and the second transformer, and is also connected to the sampling input terminal of the interleaved flyback power supply chip. The primary-side sampling circuit is used to sample the voltage of the primary windings of the first transformer and the second transformer, and output the corresponding voltage sampling signal to the interleaved flyback power supply chip.
[0029] Optionally, the interleaved flyback power supply circuit further includes:
[0030] A current detection circuit is connected to the switching circuit and also to the current input terminal of the interleaved flyback power supply chip. The current detection circuit is used to detect the operating current of the switching circuit and output a current detection signal to the interleaved flyback power supply chip. The interleaved flyback power supply chip is also used to output a first drive signal and a second drive signal according to the current detection signal.
[0031] Optionally, the current detection circuit includes a third resistor, the first end of which is connected to the switching circuit, and the second end of which is connected to the current input terminal of the interleaved flyback power supply chip.
[0032] This utility model also proposes a switching power supply, including the interleaved flyback power supply circuit described above.
[0033] This utility model also proposes a power supply device, including the switching power supply described above.
[0034] This utility model's technical solution comprises a first transformer, a second transformer, a voltage sampling circuit, an interleaved flyback power supply chip, and a switching circuit, forming an interleaved flyback power supply circuit. The voltage sampling circuit is electrically connected to both the first and second transformers, acquiring their operating voltages and outputting a voltage sampling signal. The interleaved flyback power supply chip is connected to the output of the voltage sampling circuit, alternately outputting a first drive signal and a second drive signal based on the voltage sampling signal. The switching circuit is connected in series between the interleaved flyback power supply chip and the first and second transformers, enabling the switching circuit to turn on or off the electrical connection between the interleaved flyback power supply chip and the first transformer based on the first drive signal, and to turn off the connection based on the second drive signal. By alternately outputting the first and second drive signals by the interleaved flyback power supply chip, the first and second transformers can alternately output voltages, thus forming an interleaved flyback power supply circuit, improving transformer utilization and increasing output power. Attached Figure Description
[0035] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0036] Figure 1 This is a functional module schematic diagram of an embodiment of the interleaved flyback power supply circuit of this utility model.
[0037] Figure 2 This is a functional module schematic diagram of an embodiment of the interleaved flyback power supply chip in the interleaved flyback power supply circuit of this utility model.
[0038] Figure 3 This is a schematic diagram of the circuit structure of an embodiment of the interleaved flyback power supply circuit of this utility model.
[0039] Figure 4 This is a schematic diagram of the driving waveform of the interleaved flyback power supply circuit of this utility model.
[0040] Explanation of reference numerals in the attached diagram: 10, Voltage sampling circuit; 20, Switching circuit; 30, Drive signal controller; 41, First drive circuit; 42, Second drive circuit; 50, Over / under voltage detection circuit; 60, Over-temperature detection circuit; 70, Logic controller; 80, Voltage clamping circuit; U1, Interleaved flyback power supply chip; T1, First transformer; T2, Second transformer; VCC, Power input terminal; COM, Signal receiving pin; A, First signal output pin; B, Second signal output pin; R2, First resistor; R3, Second resistor; R6, Third resistor; Q1, First MOSFET; Q2, Second MOSFET. Detailed Implementation
[0041] To make the objectives, technical solutions, and effects of this utility model clearer and more explicit, the present utility model will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0042] In the implementation methods and claims, unless otherwise specified in the text, the terms "a," "an," "the," and "the" may also include plural forms. If the embodiments of this utility model involve descriptions of "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.
[0043] It should be further understood that the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when an element is referred to as "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements present. Furthermore, "connected" or "coupled" as used herein can include wireless connections or wireless coupling. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items.
[0044] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.
[0045] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.
[0046] Switching power supplies are indispensable power electronic devices in modern society, widely used in electronics, communications, electrical engineering, energy, lighting, and home appliances. With the further development of power electronics technology, the requirements for switching power supplies in terms of size, reliability, cost, energy efficiency, and environmental friendliness are increasing. Currently, switching power supplies generally adopt forward, flyback, and push-pull topologies. Among them, the flyback topology is widely used in low-to-medium power switching power supplies due to its simple structure, ability to achieve input-output isolation, and power factor correction function. However, switching power supplies using a single transformer in a flyback topology have low transformer utilization and low output power.
[0047] To solve the above problems, this utility model proposes an interleaved flyback power supply circuit.
[0048] Reference Figure 1 In one embodiment, the interleaved flyback power supply circuit includes:
[0049] First transformer T1;
[0050] Second transformer T2;
[0051] The voltage sampling circuit 10 is electrically connected to the first transformer T1 and the second transformer T2. The voltage sampling circuit 10 is used to collect the operating voltage of the first transformer T1 and the second transformer T2 and output a voltage sampling signal.
[0052] The interleaved flyback power supply chip U1 is connected to the output terminal of the voltage sampling circuit 10. The interleaved flyback power supply chip U1 is used to alternately output a first drive signal and a second drive signal according to the voltage sampling signal.
[0053] A switching circuit 20 is connected in series between the interleaved flyback power chip U1 and the first transformer T1 and the second transformer T2. The switching circuit 20 is used to turn on or off the electrical connection between the interleaved flyback power chip U1 and the first transformer T1 according to the first drive signal, and to turn on or off the electrical connection between the interleaved flyback power chip U1 and the second transformer T2 according to the second drive signal.
[0054] In this embodiment, the voltage sampling circuit 10 can sample the operating voltage of the transformer using a high-precision voltage sensor, voltage divider circuit, or optocoupler, etc. The specific sampling method can be selected according to user needs and actual conditions. In the case of an interleaved flyback power supply circuit, the voltage sampling circuit 10 can collect the operating voltages of the first transformer T1 and the second transformer T2, and output the corresponding electrical signal, i.e., the voltage sampling signal, to the interleaved flyback power supply chip U1. The interleaved flyback power supply chip U1 can then adjust the on-time and off-time of the switching transistors in the switching circuit 20 based on the sampled voltage information through internal control logic (such as PWM signal control). For example, when the output voltage is detected to be too high, the interleaved flyback power supply chip U1 will shorten the on-time of the switching transistors, reducing the energy stored in the transformer, thereby lowering the output voltage; conversely, when the output voltage is too low, the interleaved flyback power supply chip U1 will increase the on-time of the switching transistors, causing the output voltage to rise. The judgment of whether the output voltage is high or low can be achieved by comparing it with an internally set reference voltage to obtain a difference signal. The error amplifier amplifies this difference signal and then sends it to the PWM generator or other types of modulators. The PWM generator adjusts the pulse width (in DC-DC converters) or frequency (in some frequency-modulated converters) based on the error signal, thereby controlling the on and off times of the switching elements to achieve precise regulation of the output voltage. It can be understood that by alternately outputting the first and second drive signals to the switching transistors in the switching circuit 20 through the interleaved flyback power supply chip U1, the switching transistors alternately turn on and off, allowing the first transformer T1 and the second transformer T2 to work alternately. This improves transformer utilization, reduces output ripple current, and also extends the lifespan of the electrolytic capacitors connected in parallel at the transformer output, thus reducing capacitor costs.
[0055] This utility model's technical solution comprises a first transformer T1, a second transformer T2, a voltage sampling circuit 10, an interleaved flyback power supply chip U1, and a switching circuit 20, forming an interleaved flyback power supply circuit. The voltage sampling circuit 10 is electrically connected to the first transformer T1 and the second transformer T2, and can collect the operating voltages of the first transformer T1 and the second transformer T2, outputting voltage sampling signals. The interleaved flyback power supply chip U1 is connected to the output terminal of the voltage sampling circuit 10, and can alternately output a first drive signal and a second drive signal according to the voltage sampling signals. The switching circuit 20 is connected in series. Connected between the interleaved flyback power chip U1 and the first transformer T1 and the second transformer T2, the switching circuit 20 can turn on or off the electrical connection between the interleaved flyback power chip U1 and the first transformer T1 according to the first drive signal, and turn on or off the electrical connection between the interleaved flyback power chip U1 and the second transformer T2 according to the second drive signal. By alternately outputting the first drive signal and the second drive signal by the interleaved flyback power chip U1, the first transformer T1 and the second transformer T2 can alternately output voltage, forming an interleaved flyback power supply circuit, which improves the utilization rate of the transformer and increases the output power.
[0056] Reference Figure 2 In one embodiment, the interleaved flyback power supply chip U1 includes:
[0057] The signal receiving pin COM is connected to the output terminal of the voltage sampling circuit 10;
[0058] A drive signal controller 30 is connected to the signal receiving pin COM. The drive signal controller 30 is used to output a first drive control signal and a second drive control signal according to the voltage sampling signal.
[0059] A first driving circuit 41 is connected to the driving signal controller 30. The first driving circuit 41 is used to output a first driving signal according to the first driving control signal.
[0060] The second driving circuit 42 is connected to the driving signal controller 30, and the second driving circuit 42 is used to output a second driving signal according to the second driving control signal.
[0061] The first signal output pin A is connected to the output terminal of the first driving circuit 41 and is also electrically connected to the switching circuit 20. The first driving circuit 41 outputs the first driving signal to the switching circuit 20 through the first signal output pin A.
[0062] The second signal output pin B is connected to the output terminal of the second driving circuit 42 and is also electrically connected to the switching circuit 20. The second driving circuit 42 outputs the second driving signal to the switching circuit 20 through the second signal output pin B.
[0063] In this embodiment, the interleaved flyback power supply chip U1 can be composed of a signal receiving pin COM, a drive signal controller 30, a first drive circuit 41, a second drive circuit 42, a first signal output pin A, and a second signal output pin B. The drive signal controller 30 receives the voltage sampling signal output from the voltage sampling circuit 10 through the signal receiving pin COM, and obtains the voltage output of the first transformer T1 and the second transformer T2 based on the voltage sampling signal, thereby controlling the on-time of the switching transistors in the switching circuit 20 to increase or decrease. Specifically, it outputs the first drive signal and the second drive signal to the first drive circuit 41 and the second drive circuit 42. The drive circuit can be composed of devices such as power amplifiers, MOSFETs, and IGBTs, used to convert the PWM signal into actual current and voltage to drive the switching transistors in the switching circuit 20 to turn on or off. It is understood that the interleaved flyback power supply chip U1 has a first signal output pin A and a second signal output pin B to facilitate connection with the switching transistors in the switching circuit 20 or with other devices, thereby completing the output of the first drive signal and the second drive signal. Furthermore, Figure 2 CND is the ground pin of the interleaved flyback power supply chip U1.
[0064] Reference Figure 2 In one embodiment, the interleaved flyback power supply chip U1 further includes:
[0065] The over / under voltage detection circuit 50 is used to detect the input voltage of the interleaved flyback power supply chip U1 and output an over / under voltage detection signal.
[0066] The over-temperature detection circuit 60 is used to detect the temperature of the interleaved flyback power supply chip U1 and output a temperature detection signal.
[0067] The logic controller 70 is connected to the output terminal of the over / under voltage detection circuit 50 and the output terminal of the over-temperature detection circuit 60, and is also connected to the input terminal of the first drive circuit 41 and the input terminal of the second drive circuit 42. The logic controller 70 is used to control the alternating operation logic of the first drive circuit 41 and the second drive circuit 42 according to the over / under voltage detection signal and the temperature detection signal.
[0068] The power input terminal VCC is used to connect to an external power source;
[0069] A voltage clamping circuit 80 is disposed between the power input terminal VCC and the first drive circuit 41 and the second drive circuit 42. The voltage clamping circuit 80 is used to clamp the external power supply and output it to the first drive circuit 41 and the second drive circuit 42.
[0070] In this embodiment, the interleaved flyback power supply chip U1 also includes an over / under voltage detection circuit 50, an over-temperature detection circuit 60, a logic controller 70, a power input terminal VCC, and a voltage clamping circuit 80. The over / under voltage detection circuit 50 can be a voltage divider circuit composed of two resistors to detect voltage and output a corresponding voltage signal; or a comparator circuit to compare the input voltage with a reference voltage and output a high or low level signal; or it can be a voltage detection chip or an optocoupler for voltage detection. The over-temperature detection circuit 60 can be composed of a temperature sensor or a thermistor or other device to detect temperature and output a corresponding temperature detection signal. When the input voltage of the interleaved flyback power supply chip U1 experiences overvoltage or undervoltage, the output voltage of the interleaved flyback power supply circuit must also decrease or increase. Similarly, when the temperature of the interleaved flyback power supply chip U1 is too high, the output voltage of the interleaved flyback power supply circuit needs to decrease. Therefore, the logic controller 70 can control the alternating operation logic of the first drive circuit 41 and the second drive circuit 42 based on the overvoltage / undervoltage detection signal and the temperature detection signal. For example, it can control the on-time of the switching transistor in the switching circuit 20 driven by the first drive circuit 41 and the second drive circuit 42, thereby increasing or decreasing the output voltage. Furthermore, the voltage clamping circuit 80 can be composed of diodes, Zener diodes, or other components, which can limit the voltage of the external power supply within a specific range to prevent damage to the circuit from excessively high or low voltages. Figure 2 The FB port is typically a feedback pin used to monitor the output voltage and feed it back to the interleaved flyback power supply chip U1 to achieve closed-loop control. The BI / O port is a bidirectional pin that can be used as either an input or output.
[0071] Reference Figure 3 In one embodiment, the switching circuit 20 includes a first resistor R2, a second resistor R3, a first MOSFET Q1, and a second MOSFET Q2. The first end of the first resistor R2 is connected to the first signal output pin A, the second end of the first resistor R2 is connected to the gate of the first MOSFET Q1, the source of the first MOSFET Q1 is connected to the ground pin of the interleaved flyback power supply chip U1, and the drain of the first MOSFET Q1 is connected to the first transformer T1. The first end of the second resistor R3 is connected to the second signal output pin B, the second end of the second resistor R3 is connected to the gate of the second MOSFET Q2, the source of the second MOSFET Q2 is connected to the ground pin of the interleaved flyback power supply chip U1, and the drain of the second MOSFET Q2 is connected to the second transformer T2.
[0072] In this embodiment, the first resistor R2 and the second resistor R3 can be used to limit the gate current of the MOSFET, protecting the MOSFET and the driving circuit. The first MOSFET Q1 and the second MOSFET Q2 can be either NMOS or PMOS transistors; it should be noted that the specific control method needs to be changed accordingly depending on the selected MOSFET, and should be set according to the actual situation and user requirements. When the first MOSFET Q1 is turned on, the first transformer T1 will start working and output voltage; when the second MOSFET Q2 is turned on, the second transformer T2 will start working and output voltage.
[0073] In one embodiment, the voltage sampling circuit 10 includes:
[0074] The secondary-side sampling circuit is connected to the secondary windings of the first transformer T1 and the second transformer T2, and is also connected to the sampling input terminal of the interleaved flyback power supply chip U1. The secondary-side sampling circuit is used to sample the voltage of the secondary windings of the first transformer T1 and the second transformer T2, and output the corresponding voltage sampling signal to the interleaved flyback power supply chip U1.
[0075] In this embodiment, the voltage sampling circuit 10 can be a secondary-side sampling circuit, sampling the voltage of the secondary windings of the first transformer T1 and the second transformer T2. The secondary-side sampling circuit directly samples the output voltage. These signals can be obtained using a high-precision voltage sensor or a voltage divider circuit. For example, in a DC-DC converter, the output voltage is sampled through a resistor divider network, and the actual output voltage is proportionally reduced before being sent to the sampling input of the controller. The sampled voltage or current signal is compared with an internally set reference voltage or reference current. An error amplifier amplifies this difference signal and then sends it to a PWM (Pulse Width Modulation) generator or other type of modulator. The PWM generator adjusts the pulse width (in a DC-DC converter) or frequency (in some frequency-modulated converters) according to the error signal, thereby controlling the on and off times of switching elements (such as MOSFETs) to achieve precise regulation of the output voltage or current. When the output voltage is higher than the reference voltage, the PWM pulse width decreases, shortening the on-time of the switching elements and causing the output voltage to drop. Because the output is controlled directly on the secondary side, high accuracy in output voltage and current can be achieved. The output voltage or current can be precisely maintained near the set value with a small error range. Various complex control strategies can be easily implemented, such as constant voltage control, constant current control, or a combination of both (constant voltage / constant current mode switching). In some battery charging applications, constant current charging can be used initially, switching to constant voltage charging once the battery voltage reaches a certain value. Figure 3 The secondary-side sampling circuit can be implemented using an optocoupler. The drive waveform of the interleaved flyback power supply circuit employing the secondary-side sampling circuit can be found in [reference needed]. Figure 4 In this diagram, Gate A is the signal that controls the conduction of the first MOSFET Q1, and Gate B is the signal that controls the conduction of the second MOSFET Q2. It should be noted that Gate B turns on when Gate A completes one half of its cycle; Gate B turns on in the next cycle when Gate B completes one half of its cycle; and the conduction times of Gate A and Gate B are the same, increasing or decreasing simultaneously. Ton represents the duty cycle of the PWM signal. The 20% duty cycle diagram illustrates the waveform under light load; the 60% duty cycle diagram illustrates the waveform under heavy load. Furthermore, in the 60% duty cycle diagram, the duty cycle (cycle-to-on-time ratio) can be greater than 50% within one cycle of a single drive signal.
[0076] In one embodiment, the voltage sampling circuit 10 includes:
[0077] The primary-side sampling circuit is connected to the primary winding of the first transformer T1 and the primary winding of the second transformer T2, and is also connected to the sampling input terminal of the interleaved flyback power supply chip U1. The primary-side sampling circuit is used to sample the voltage of the primary winding of the first transformer T1 and the primary winding of the second transformer T2, and output the corresponding voltage sampling signal to the interleaved flyback power supply chip U1.
[0078] In this embodiment, the voltage sampling circuit 10 can be a primary-side sampling circuit, sampling the voltage of the primary winding of the first transformer T1 and the primary winding of the second transformer T2. When the switching transistor is on, energy is stored in the primary inductance of the transformer; when the switching transistor is off, the stored energy is coupled to the secondary winding through the transformer to power the load. The voltage of the auxiliary winding has a certain proportional relationship with the voltage of the primary winding and is also indirectly related to the output voltage. By sampling the voltage of the auxiliary winding, information related to the output voltage can be obtained. Based on the sampled voltage information, the interleaved flyback power supply chip U1 adjusts the on-time and off-time of the switching transistor through its internal control logic (usually PWM control). For example, when the output voltage is detected to be too high, the controller will shorten the on-time of the switching transistor, reduce the energy stored in the transformer, and thus lower the output voltage; conversely, when the output voltage is too low, it will increase the on-time of the switching transistor. The sampling method of the primary-side sampling circuit can be applied to low-power switching power supplies, such as mobile phone chargers and small power adapters.
[0079] The choice between a secondary-side sampling circuit and a primary-side sampling circuit for the specific voltage sampling circuit 10 can be determined based on the actual situation and user requirements.
[0080] In one embodiment, the interleaved flyback power supply circuit further includes:
[0081] A current detection circuit is connected to the switching circuit 20 and also to the current input terminal of the interleaved flyback power supply chip U1. The current detection circuit is used to detect the operating current of the switching circuit 20 and output a current detection signal to the interleaved flyback power supply chip U1. The interleaved flyback power supply chip U1 is also used to output a first drive signal and a second drive signal according to the current detection signal.
[0082] In this embodiment, the current detection circuit performs cycle-by-cycle current detection on the switching transistor in the switching circuit 20 and outputs the current detection signal to the interleaved flyback power supply chip U1. This improves power supply stability, prevents overcurrent and overload conditions, and enhances dynamic response. When the load changes abruptly, the power supply can quickly adjust its output to maintain a stable output voltage. Furthermore, it can implement various protection functions, such as overcurrent protection and short-circuit protection. When the detected current exceeds a set threshold, the power supply can immediately take measures (such as turning off the switching transistor or reducing output power) to protect the circuit and load. It can also optimize switching losses and conduction losses, thereby improving overall conversion efficiency. Figure 2 CS is the current signal receiving pin COM of the interleaved flyback power supply chip U1.
[0083] Furthermore, referring to Figure 3 In one embodiment, the current detection circuit includes a third resistor R6. The first end of the third resistor R6 is connected to the switching circuit 20, and the second end of the third resistor R6 is connected to the current input terminal of the interleaved flyback power supply chip U1. In this embodiment, the third resistor R6 can be used to sample the current of the switching transistor in the switching circuit 20, and output a current signal to the current input terminal of the interleaved flyback power supply chip U1.
[0084] This utility model also proposes a switching power supply.
[0085] In one embodiment, the switching power supply includes the interleaved flyback power supply circuit described above. It is understood that, since the switching power supply of this invention uses the aforementioned interleaved flyback power supply circuit, the embodiments of the switching power supply of this invention include all the technical solutions of all embodiments of the aforementioned interleaved flyback power supply circuit, and the achieved technical effects are completely identical, and will not be repeated here.
[0086] This utility model also proposes a power supply device.
[0087] In one embodiment, the power supply device includes a switching power supply as described above. It is understood that since the power supply device of this invention uses the aforementioned switching power supply, the embodiments of the power supply device of this invention include all the technical solutions of all the embodiments of the aforementioned switching power supply, and the achieved technical effects are completely the same, and will not be repeated here.
[0088] It should be understood that the application of this utility model is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.
Claims
1. An interleaved flyback power supply circuit, characterized by comprising: include: First transformer; Second transformer; A voltage sampling circuit is electrically connected to the first transformer and the second transformer. The voltage sampling circuit is used to collect the operating voltage of the first transformer and the second transformer and output a voltage sampling signal. An interleaved flyback power supply chip is connected to the output terminal of the voltage sampling circuit. The interleaved flyback power supply chip is used to alternately output a first drive signal and a second drive signal according to the voltage sampling signal. A switching circuit is connected in series between the interleaved flyback power supply chip and the first transformer and the second transformer. The switching circuit is used to turn on or off the electrical connection between the interleaved flyback power supply chip and the first transformer according to a first drive signal, and to turn on or off the electrical connection between the interleaved flyback power supply chip and the second transformer according to a second drive signal.
2. The interleaved flyback power supply circuit of claim 1, wherein, The interleaved flyback power supply chip includes: The signal receiving pin is connected to the output terminal of the voltage sampling circuit. A drive signal controller is connected to the signal receiving pin, and the drive signal controller is used to output a first drive control signal and a second drive control signal according to the voltage sampling signal; A first driving circuit is connected to the driving signal controller, and the first driving circuit is used to output a first driving signal according to the first driving control signal. A second driving circuit is connected to the driving signal controller, and the second driving circuit is used to output a second driving signal according to the second driving control signal. The first signal output pin is connected to the output terminal of the first driving circuit and is also electrically connected to the switching circuit. The first driving circuit outputs the first driving signal to the switching circuit through the first signal output pin. The second signal output pin is connected to the output terminal of the second driving circuit and is also electrically connected to the switching circuit. The second driving circuit outputs the second driving signal to the switching circuit through the second signal output pin.
3. The interleaved flyback power supply circuit of claim 2, wherein, The interleaved flyback power supply chip also includes: An over / under voltage detection circuit is used to detect the input voltage of the interleaved flyback power supply chip and output an over / under voltage detection signal. An over-temperature detection circuit is used to detect the temperature of the interleaved flyback power supply chip and output a temperature detection signal; A logic controller is connected to the output terminals of the over / under voltage detection circuit and the over-temperature detection circuit, and also to the input terminals of the first driving circuit and the second driving circuit. The logic controller is used to control the alternating operation logic of the first driving circuit and the second driving circuit according to the over / under voltage detection signal and the temperature detection signal. Power input terminal, used to connect to an external power source; A voltage clamping circuit is disposed between the power input terminal and the first driving circuit and the second driving circuit. The voltage clamping circuit is used to clamp the external power supply and output it to the first driving circuit and the second driving circuit.
4. The interleaved flyback power supply circuit of claim 2, wherein, The switch circuit comprises a first resistor, a second resistor, a first MOS tube and a second MOS tube, a first end of the first resistor is connected with the first signal output pin, a second end of the first resistor is connected with a gate of the first MOS tube, a source of the first MOS tube is connected with a ground pin of the interleaved flyback power supply chip, a drain of the first MOS tube is connected with the first transformer, a first end of the second resistor is connected with the second signal output pin, a second end of the second resistor is connected with a gate of the second MOS tube, a source of the second MOS tube is connected with the ground pin of the interleaved flyback power supply chip, and a drain of the second MOS tube is connected with the second transformer.
5. The interleaved flyback power supply circuit of claim 1, wherein, The voltage sampling circuit comprises: The primary side sampling circuit is connected with the primary side windings of the first transformer and the second transformer and is also connected with a sampling input end of the interleaved flyback power supply chip, and is used for sampling voltages of the primary side windings of the first transformer and the second transformer and outputting corresponding voltage sampling signals to the interleaved flyback power supply chip.
6. The interleaved flyback power supply circuit of claim 1, wherein, The voltage sampling circuit comprises: The primary side sampling circuit is connected with the primary side windings of the first transformer and the second transformer and is also connected with a sampling input end of the interleaved flyback power supply chip, and is used for sampling voltages of the primary side windings of the first transformer and the second transformer and outputting corresponding voltage sampling signals to the interleaved flyback power supply chip.
7. The interleaved flyback power supply circuit of claim 1, wherein, The interleaved flyback power supply circuit further comprises: The current detection circuit is connected with the switch circuit and is also connected with a current input end of the interleaved flyback power supply chip, and is used for detecting working currents of the switch circuit and outputting current detection signals to the interleaved flyback power supply chip, and the interleaved flyback power supply chip is further used for outputting first driving signals and second driving signals according to the current detection signals.
8. The interleaved flyback power supply circuit of claim 7, wherein, The current detection circuit comprises a third resistor, a first end of the third resistor is connected with the switch circuit, and a second end of the third resistor is connected with the current input end of the interleaved flyback power supply chip.
9. A switching power supply, characterized by The interleaved flyback power supply circuit comprises the interleaved flyback power supply circuit according to any one of claims 1-8.
10. A power supply device characterized by comprising: The switch power supply comprises the switch power supply according to claim 9.