SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a multi-output flyback switching power supply circuit and an air conditioner, which can reduce one path of output additionally occupied by a power supply control chip and simplify the circuit structure.
The utility model provides a technical scheme as follows:
in a first aspect, the present invention provides a multi-output flyback switching power supply circuit, which includes a power control chip and a transformer;
the transformer comprises a first secondary winding and at least one second secondary winding;
the first secondary winding and the second secondary winding are used for supplying power to a load;
the first secondary winding is also used for supplying power to the power control chip.
According to the scheme, the first secondary winding supplies power to the load and the power control chip simultaneously, output of the power control chip is not required to be independently set, the number of windings occupied is reduced, the structural complexity of the switching power supply circuit is reduced, and the reliability is improved while the cost is reduced.
In an optional embodiment, the power control chip includes a power terminal and a ground terminal;
the first secondary winding comprises a first end, a second end and a rectifying circuit, and the rectifying circuit comprises a first diode;
a first end of the first secondary winding is connected with an anode of the first diode, a cathode of the first diode forms a first power output end, and a second end of the first secondary winding is connected with a first reference ground;
the first power supply output end is connected with a power supply end of the power supply control chip;
and the second end of the first secondary winding is connected with the grounding end of the power supply control chip.
In an optional embodiment, the multi-output flyback switching power supply circuit includes a first capacitor, an anode of the first capacitor is connected to a power supply terminal of the power supply control chip, a cathode of the first capacitor is connected to a second reference ground, and the first capacitor is configured to supply power to the power supply control chip before the multi-output flyback switching power supply circuit is started by using pre-stored energy.
In an optional embodiment, the flyback switching power supply circuit includes a second capacitor, where the second capacitor is connected in parallel to two ends of the first capacitor, and the second capacitor is used to filter a power supply signal provided by the first capacitor.
In an optional embodiment, the multi-output flyback switching power supply circuit includes a second diode, an anode of the second diode is connected to the first power output terminal, and a cathode of the second diode is connected to an anode of the first capacitor;
the second diode is used for blocking the first capacitor from discharging.
In an alternative embodiment, the multi-output flyback switching power supply circuit includes a rectifier bridge, and the transformer includes a primary winding;
the rectifier bridge is used for rectifying a power supply signal and comprises a first rectifying output end and a second rectifying output end;
the first rectification output end is connected with the primary winding;
the second rectified output is electrically connected to the second reference ground.
In an optional embodiment, the multi-output flyback switching power supply circuit further includes a first resistor, a first end of the first resistor is connected to the first reference ground, and a second end of the first resistor is connected to the second reference ground.
In an alternative embodiment, the first resistor has a resistance value of less than 10 ohms.
In an optional embodiment, the rectifier circuit further includes a third capacitor, a first end of the third capacitor is electrically connected to the first power output terminal, and a second end of the third capacitor is connected to the second end of the first secondary winding; the third capacitor is used for filtering the signal output by the first secondary winding.
In a second aspect, the present invention provides an air conditioner comprising a multi-output flyback switching power supply circuit as described in any one of the preceding embodiments.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like, indicate orientations or positional relationships that are based on the orientations or positional relationships shown in the drawings, or the orientations or positional relationships that the products of the present invention conventionally put into use, or the orientations or positional relationships that are conventionally understood by those skilled in the art, and are used merely for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the equipment or elements referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The flyback switching power supply circuit is one of main circuits of an air conditioner controller and provides a load power supply for variable frequency control, the load controlled by an external unit of the variable frequency air conditioner is more in variety, multiple power supplies are needed under general conditions, and part of commercial machine types need to be additionally provided with one path of isolated power supply, so that the power supply circuit is more complex, windings are increased, the cost is increased, and the reliability of the system is reduced.
As shown in fig. 1, fig. 1 shows a schematic diagram of a conventional flyback switching power supply circuit, which has three outputs: VOUT1, VOUT2 and VOUT 3. Wherein VOUT1 is mainly used for supplying power to the rear-stage load; VOUT2 is an isolated power supply, and is mainly used for supplying power to circuits which are easy to be touched by hands, such as 485 communication; VOUT3 is used to provide operating power to the switching power chip. In addition, the primary winding needs four windings in total, the structure is complex, the cost is high, and the reliability is reduced.
Based on the technical problem, the utility model provides a novel multi-output flyback switching power supply circuit, which does not need to provide one path of winding output for a power supply control chip to supply power independently, and simplifies the circuit structure.
Referring to fig. 2, fig. 2 is a schematic circuit diagram of a multi-output flyback switching power supply circuit 100 according to an embodiment of the present invention.
The multi-output flyback switching power supply circuit 100 includes a power control chip IC15 and a transformer TR, wherein the transformer TR is used for transforming and converting a high-voltage signal output by the rectifier bridge B to provide multiple outputs. Wherein the transformer TR comprises a first secondary winding T2 and at least one second secondary winding T3; the first secondary winding T2 and the second secondary winding T3 can be used for supplying power to a load; the first secondary winding T2 is further used for supplying power to the power control chip IC15, and the power control chip IC15 controls the on/off of the signal on the primary side of the transformer TR.
The first secondary winding T2 can simultaneously power the load and the power control chip IC 15. Taking the multi-output flyback switching power supply circuit 100 in the air conditioner as an example, the air conditioner further comprises a controller and other loads, the first secondary winding T2 can simultaneously supply power to the power control chip IC15 and the controller, and one output does not need to be independently set for the power control chip IC15, so that the occupation of one winding is reduced, the structural complexity of the multi-output flyback switching power supply circuit 100 is reduced, the reliability is improved, and the cost is reduced.
For example, the power control chip IC15 includes a power supply terminal VCC and a ground terminal GND, the first secondary winding T2 includes a first terminal and a second terminal opposite to each other, and the first secondary winding T2 further includes a rectifying circuit.
The first end T21 of the first secondary winding T2 forms a first power output terminal Vout1 after passing through the rectifying circuit, and is used for providing a power signal to the power control chip IC15 or other loads, and the second end T22 of the first secondary winding T2 is connected to the first ground GND1 as a ground terminal.
In a possible implementation manner, the rectifying circuit includes a first diode D1, the first end T21 of the first secondary winding T2 is connected to the anode of the first diode D1, the cathode of the first diode D1 forms a first power output terminal Vout1, the signal output by the first secondary winding T2 can be rectified by the first diode D1, so that the signal flows in a single direction, only the anode of the first diode D1 can flow to the cathode of the first diode D1, the signal can be prevented from flowing backwards, and the first power output terminal Vout1 (i.e., the cathode of the first diode D1) is led to the power control chip IC15, so that the power supply to the power control chip IC15 can be performed.
In a possible implementation manner, the rectifier circuit further includes a third capacitor C3, a first end of the third capacitor C3 is electrically connected to the first power output terminal Vout1, a second end of the third capacitor C3 is connected to the second end T22 of the first secondary winding T2, and the third capacitor C3 is used as a filter resistor for filtering a signal output by the first secondary winding T2 (i.e., a signal output by the first power output terminal Vout 1).
In the embodiment of the utility model, the first power output terminal Vout1 is connected to the power terminal VCC of the power control chip IC15, and the second terminal T22 of the first secondary winding T2 is connected to the ground terminal GND of the power control chip IC 15. When the multi-output flyback switching power supply circuit 100 is started, the first secondary winding T2 supplies power to the power control chip IC 15.
In some possible implementations, the multi-output flyback switching power supply circuit 100 includes a first capacitor E1, an anode of the first capacitor E1 is connected to the power supply terminal VCC of the power control chip IC15, a cathode of the first capacitor E1 is connected to the second reference ground GND2, and the first capacitor E1 is configured to supply power to the power control chip IC15 before the multi-output flyback switching power supply circuit 100 is started by using the pre-stored energy.
Before the multi-output flyback switching power supply circuit 100 is started, the first secondary winding T2 cannot be effectively output temporarily, at this time, the power control chip IC15 mainly depends on an internal high-voltage current source to supply the first capacitor E1 through a power supply terminal VCC pin, the first capacitor E1 discharges working power for the power control chip IC15, and power loss is increased due to the internal high-voltage current source, so that the temperature is raised, and power is supplied by an external winding after the multi-output flyback switching power supply circuit 100 is started.
In some possible implementation manners, the first capacitor E1 may be an electrolytic capacitor, and the rated capacity of the electrolytic capacitor is high, so that to avoid the chip damage caused by too high discharge of the first capacitor E1, the flyback switching power supply circuit is further provided with a second capacitor C2, the second capacitor C2 is connected in parallel to two ends of the first capacitor E1, and the second capacitor C2 is used to filter a power supply signal provided by the first capacitor E1, so as to prevent the power supply control chip IC15 from being damaged due to overcurrent or overvoltage.
In order to avoid the backflow of the electric energy released by the first capacitor E1, in the embodiment of the utility model, the multi-output flyback switching power supply circuit 100 further includes a second diode D2 serving as a backflow prevention diode, an anode of the second diode D2 is connected to the first power output terminal Vout1, and a cathode of the second diode D2 is connected to an anode of the first capacitor E1; the second diode D2 is used to block the first capacitor E1 from discharging reversely, so as to ensure that the signal flow direction between the first power output terminal Vout1 and the power supply terminal VCC of the power control chip IC15 does not change.
The multi-output flyback switching power supply circuit 100 is configured to transform a signal that is input to a primary winding T1 of a transformer TR, and output the signal through a plurality of secondary windings to provide different power supply signals.
Referring to fig. 2, the rectifier bridge B is used for rectifying the power signal, and includes a first rectifying output terminal B1 and a second rectifying output terminal B2. The first rectified output terminal B1 is connected to the primary winding T1, and the second rectified output terminal B2 is electrically connected to a second ground reference GND 2. In some possible implementations, for example, taking an application scenario as an inverter air conditioner, the signal rectified by the rectifier bridge B is further used to power a part of high-voltage circuits, such as a PFC circuit of the inverter air conditioner.
Because the controller and the PFC circuit of the variable frequency air conditioner adopt a non-isolation scheme, namely the strong electric ground of the power control chip IC15 and the weak electric ground output by the secondary winding are in common ground, the grounding end of the PFC circuit and the grounding end of the controller are connected together because of the requirement of variable frequency control sampling.
In the solution provided by the embodiment of the present invention, while the power provided by the first secondary winding T2 is introduced to the power terminal VCC pin of the power control chip IC15, the ground terminal (the first ground reference GND1) of the first secondary winding T2 must be synchronously connected to the ground terminal GND pin of the power control chip IC15, and for the whole PCB layout, there are two common points, which may form a ground loop, and the presence of the ground loop may introduce interference, which may cause unstable operation of the whole system.
In order to solve the problem of the ground loop, a first resistor R1 is arranged between a primary side ground (i.e., the second reference ground GND2) and a secondary side ground (i.e., the first reference ground GND1) of the transformer TR, and in order to ensure the effectiveness of connection between the first power output terminal Vout1 of the first secondary winding T2 and the power supply terminal VCC pin of the power control chip IC15, the resistance value of the first resistor R1 must be very small.
Referring to fig. 2, a first end of the first resistor R1 is connected to the first ground reference GND1, a second end of the first resistor R1 is connected to the second ground reference GND2, and the first resistor R1 is disposed between the primary ground terminal and the secondary ground terminal of the transformer TR, so as to reduce interference caused by a ground loop.
The multi-output flyback switching power supply circuit 100 provided in this embodiment further includes at least one second secondary winding T3, and the second secondary winding T3 is used for supplying power to a load of a subsequent stage. The number of the second secondary windings T3 can be set according to actual requirements, and the form of the signal provided by the second secondary winding T3 can also be adjusted according to actual requirements, for example, the second secondary winding T3 can provide the isolated power source Vout2, which is not limited in this embodiment.
In a possible implementation manner, a corresponding rectifying circuit may be provided at an output end of each second secondary winding T3, so as to rectify the electrical signal output by the secondary winding.
Based on the multi-output flyback switching power supply circuit 100 provided in the foregoing embodiment, the present invention provides an air conditioner including the multi-output flyback switching power supply circuit 100 provided in the foregoing embodiment. It should be noted that the technical effects and basic principles of the air conditioner provided in the embodiment of the present application are substantially the same as those of the multi-output flyback switching power supply circuit 100 provided in the foregoing embodiment, and for the sake of brief description, the embodiment of the present application will not be described in detail, and the embodiment of the present application does not describe in detail, and please refer to the relevant contents in the foregoing embodiment.
The air conditioner comprises a PFC circuit and a controller, wherein the PFC circuit supplies power for high voltage, the controller supplies power for low voltage, the controller can be supplied with power by utilizing the first secondary winding T2 of the multi-output flyback switching power supply circuit 100, and when the controller is supplied with power, the first secondary winding T2 can also supply power to a power control chip IC15, so that the occupation of one path of winding is reduced, the complexity of the circuit is reduced, the multi-output flyback switching power supply circuit 100 can be provided with one path of secondary winding less, or more paths of windings cover more application scenes.
In summary, the present application provides a multi-output flyback switching power supply circuit, which includes a power control chip and a transformer; the transformer comprises a first secondary winding and at least one second secondary winding; the first secondary winding and the second secondary winding are used for supplying power to a load; the first secondary winding is also used for supplying power to the power control chip. According to the scheme, the first secondary winding of the transformer supplies power to the load and the power control chip simultaneously, output of the power control chip is not required to be set independently, occupation of the winding of the same path is reduced, the structural complexity of the switching power supply circuit is reduced, meanwhile, the resistor is arranged between the primary side grounding end and the secondary side grounding end of the transformer, interference caused by a ground wire loop can be eliminated, and the reliability is improved while the cost is reduced.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.