Switching power supply circuit and electric appliance using same

Abstract

The utility model discloses a switching power supply circuit and an electric appliance applying the same, the switching power supply circuit comprises a rectification filtering unit, a first output unit and a second output unit, the first output unit comprises a transformer T1 electrically connected with the output end of the rectification filtering unit, and the first output unit can output constant voltage direct current. The second output unit comprises a step-down chip IC1 and a transformer T2 electrically connected with the output end of the rectifying and filtering unit, the input end of the step-down chip IC1 is electrically connected with a secondary coil of the transformer T2 for constant-current direct-current output, and the voltage of the constant-voltage direct-current output is smaller than that of the constant-current direct-current output.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply circuit technology, and in particular to a switching power supply circuit and an electrical appliance using the same. Background Technology

[0002] Currently, switching power supplies used in appliances such as bathroom heaters, electric clothes dryers, fan lights, and indoor heaters generally employ complex non-isolated power supply circuits. These circuits first boost the 24V DC voltage from the secondary side of the transformer and then step it down to drive the corresponding load. However, the connection and assembly of these circuits must comply with national safety standards. The safety protection measures adopted by non-isolated power supplies are generally more expensive and structurally more complex than those of isolated power supply circuits. Utility Model Content

[0003] The purpose of this utility model is to solve at least one of the technical problems existing in the prior art, and to provide a low-cost and highly reliable switching power supply circuit and electrical appliance.

[0004] According to a first aspect embodiment of the present invention, a switching power supply circuit includes a rectifier and filter unit, a first output unit, and a second output unit. The first output unit includes a transformer T1 electrically connected to the output terminal of the rectifier and filter unit, and the first output unit is capable of constant voltage DC output. The second output unit includes a step-down chip IC1 and a transformer T2 electrically connected to the output terminal of the rectifier and filter unit. The input terminal of the step-down chip IC1 is electrically connected to the secondary coil of the transformer T2 to provide constant current DC output. The voltage of the constant voltage DC output is less than the voltage of the constant current DC output.

[0005] According to the second aspect of the present invention, an electrical appliance using the switching power supply circuit described in any of the preceding claims includes a housing and a first load, a second load, and a circuit board disposed in the housing. The switching power supply circuit is disposed on the circuit board, and the circuit board is further provided with a main control chip IC2. The main control chip IC2 is electrically connected to the switching power supply circuit, the first load, and the second load respectively to control the operating state of the corresponding circuits. The output terminal of the first output unit is electrically connected to the power supply terminal of the first load, and the output terminal of the second output unit is electrically connected to the power supply terminal of the second load.

[0006] The switching power supply circuit and electrical appliance according to the embodiments of this utility model have at least the following beneficial effects: external AC power is rectified by a rectifier and filter unit to obtain a rectified voltage. The rectified voltage is then transformed by transformer T1 into a smaller constant voltage DC output voltage to drive a smaller first load (such as a DC motor in a bathroom heater). At the same time, the rectified voltage is transformed by transformer T2 into a higher DC voltage, and then stepped down by step-down chip IC1 to obtain a larger constant current DC output voltage to drive a larger second load (such as an LED module in a bathroom heater). Due to the function of transformer T2 and step-down chip IC1, not only is an isolation circuit formed, improving safety and reliability, but it can also be matched with low-cost ordinary wiring terminals. Moreover, step-down chip IC1 makes the overall structure of the switching power supply circuit simple, suitable for ultra-thin housings, and saves costs.

[0007] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0008] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings;

[0009] Figure 1 This is the circuit diagram of a switching power supply circuit.

[0010] Figure 2 This is the circuit structure diagram of the relay module;

[0011] Figure 3 This is the circuit diagram of the main control chip IC2;

[0012] Figure 4 It is a structural diagram of the electrical appliance;

[0013] Figure 5 This is an exploded structural diagram of an electrical appliance. Detailed Implementation

[0014] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0015] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0016] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0017] Reference Figures 1 to 5 This utility model discloses a switching power supply circuit, including a rectifier and filter unit 10, a first output unit 11, and a second output unit 12. The first output unit 11 includes a transformer T1 electrically connected to the output terminal of the rectifier and filter unit 10, and the first output unit 11 is capable of constant voltage DC output. The second output unit 12 includes a step-down chip IC1 and a transformer T2 electrically connected to the output terminal of the rectifier and filter unit 10. The input terminal of the step-down chip IC1 is electrically connected to the secondary coil of the transformer T2 to provide constant current DC output. The voltage of the constant voltage DC output is less than the voltage of the constant current DC output. External AC power is rectified by a rectifier and filter unit to obtain a rectified voltage. This rectified voltage is then converted by transformer T1 into a smaller constant DC output voltage to drive a smaller first load (such as a DC motor in a bathroom heater). Simultaneously, the rectified voltage is converted by transformer T2 into a higher DC voltage, which is then stepped down by buck chip IC1 to obtain a larger constant current DC output voltage to drive a larger second load (such as an LED module in a bathroom heater). Due to the functions of transformer T2 and buck chip IC1, an isolation circuit is formed, improving safety and reliability. It can be matched with low-cost ordinary terminal blocks. Furthermore, buck chip IC1 makes the overall structure of the switching power supply circuit simple, suitable for ultra-thin housings 30, saving costs.

[0018] Furthermore, it includes a PFC unit 20, whose input terminal is electrically connected to the output terminal of the rectifier and filter unit 10, and whose output terminal is electrically connected to the primary coil of the transformer T1, thereby playing a role in power factor correction and improving the reliability of the circuit.

[0019] Furthermore, the first output unit 11 includes a diode D1, a resistor R1, a capacitor C1, a capacitor C2, and a loop filter L1. The diode D1 has a reverse cutoff function. The anode of the diode D1 and one end of the capacitor C1 are electrically connected to one end of the secondary coil of the transformer T1, respectively. The other end of the capacitor C1 is electrically connected to one end of the resistor R1. The resistor R1 and the capacitor C1 serve as filters. The other end of the resistor R1 and the cathode of the diode D1 are electrically connected to one end of the capacitor C2 and one input terminal of the loop filter Lf1, respectively. The other end of the capacitor C2, the other end of the secondary coil of the transformer T1, and the other input terminal of the loop filter Lf1 are grounded, respectively. The output terminal of the loop filter Lf1 outputs a constant voltage DC output.

[0020] Furthermore, the second output unit 12 includes a diode D2, a resistor R2, a capacitor C3, a capacitor C4, a diode D3, and a coil L1. The anode of diode D2 and one end of capacitor C3 are electrically connected to one end of the secondary coil of transformer T2, respectively. The other end of capacitor C3 is electrically connected to one end of resistor R2. The other end of resistor R2 and the cathode of diode D2 are electrically connected to one end of capacitor C4, the cathode of diode D3, and the input terminal of buck converter IC1, respectively. The output terminal of buck converter IC1 is electrically connected to the anode of diode D3 and one end of coil L1, respectively. A constant current DC output voltage is formed between the other end of coil L1 and the cathode of diode D3. Furthermore, it also includes a resistor R3 and a capacitor C5. Resistor R3 and capacitor C5 are connected in parallel to form a parallel circuit with filtering function. One end of the parallel circuit is electrically connected to the cathode of diode D3, and the other end of the parallel circuit is electrically connected to the other end of coil L1, to further filter the constant current DC output voltage.

[0021] like Figures 2 to 3 This utility model also includes an electrical appliance that utilizes the aforementioned switching power supply circuit. The appliance includes a housing 30 and a relay module 31, a first load, a second load, and a circuit board 32 disposed within the housing 30. The switching power supply circuit is mounted on the circuit board 32, which also houses a main control chip IC2. The main control chip IC2 is electrically connected to the switching power supply circuit, the first load, and the second load to control the operating state of the corresponding circuits. The output terminal of the first output unit 11 is electrically connected to the power supply terminal of the first load, and the output terminal of the second output unit 12 is electrically connected to the power supply terminal of the second load. The power supply terminal of the relay module 31 is electrically connected to the output terminal of the first output unit 11, and the main control chip IC2 is electrically connected to the input terminal of the relay module 31. The output terminals of the relay module 31 are electrically connected to the first load and the second load to control the operating state of the corresponding loads.

[0022] like Figure 4 and Figure 5As shown, the appliance is a bathroom heater. The first load is a low-power DC motor, and the second load is a higher-power LED module. The constant voltage DC output voltage is 24V, and the constant current DC output voltage is generally 110V. The secondary side voltage of transformer T2 can be 160V. The 160V DC voltage is stepped down by the step-down chip IC1 to obtain the 110V voltage used to drive the LED module. It has good isolation effect and better safety and reliability. This switching power supply circuit can be applied in the metal casing 30 and matched with ordinary terminals, which is low cost. Moreover, the step-down chip IC1 can make the overall structure of the switching power supply circuit simple and suitable for ultra-thin casing 30, further saving costs.

[0023] It will be readily understood by those skilled in the art that the above preferred methods can be freely combined and superimposed without conflict.

[0024] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. A switching power supply circuit, characterized in that, include: The unit comprises a rectifier and filter unit (10), a first output unit (11), and a second output unit (12). The first output unit (11) includes a transformer T1 electrically connected to the output terminal of the rectifier and filter unit (10). The first output unit (11) is capable of constant voltage DC output. The second output unit (12) includes a step-down chip IC1 and a transformer T2 electrically connected to the output terminal of the rectifier and filter unit (10). The input terminal of the step-down chip IC1 is electrically connected to the secondary coil of the transformer T2 to provide constant current DC output. The voltage of the constant voltage DC output is less than the voltage of the constant current DC output.

2. The switching power supply circuit according to claim 1, characterized in that: It includes a PFC unit (20), the input terminal of which is electrically connected to the output terminal of the rectifier filter unit (10), and the output terminal of which is electrically connected to the primary coil of the transformer T1.

3. The switching power supply circuit according to claim 1, characterized in that: The first output unit (11) includes a diode D1, a resistor R1, a capacitor C1, a capacitor C2 and a loop filter L1. The anode of the diode D1 and one end of the capacitor C1 are electrically connected to one end of the secondary coil of the transformer T1, and the other end of the capacitor C1 is electrically connected to one end of the resistor R1. The other end of the resistor R1 and the cathode of the diode D1 are electrically connected to one end of the capacitor C2 and one input terminal of the loop filter Lf1, respectively. The other end of the capacitor C2, the other end of the secondary coil of the transformer T1 and the other input terminal of the loop filter Lf1 are grounded, and the output terminal of the loop filter Lf1 outputs a constant voltage DC output voltage.

4. The switching power supply circuit according to claim 1, characterized in that: The second output unit (12) includes a diode D2, a resistor R2, a capacitor C3, a capacitor C4, a diode D3 and a coil L1. The anode of the diode D2 and one end of the capacitor C3 are electrically connected to one end of the secondary coil of the transformer T2, respectively. The other end of the capacitor C3 is electrically connected to one end of the resistor R2. The other end of the resistor R2 and the cathode of the diode D2 are electrically connected to one end of the capacitor C4, the cathode of the diode D3 and the input terminal of the step-down chip IC1, respectively. The output terminal of the step-down chip IC1 is electrically connected to the anode of the diode D3 and one end of the coil L1, respectively. A constant current DC output voltage is formed between the other end of the coil L1 and the cathode of the diode D3.

5. The switching power supply circuit according to claim 4, characterized in that: It also includes a resistor R3 and a capacitor C5, which are connected in parallel to form a parallel circuit. One end of the parallel circuit is electrically connected to the cathode of the diode D3, and the other end of the parallel circuit is electrically connected to the other end of the coil L1.

6. An electrical appliance that uses the switching power supply circuit as described in any one of claims 1 to 5, characterized in that: The device includes a housing (30) and a first load, a second load, and a circuit board (32) disposed in the housing (30). The switching power supply circuit is disposed on the circuit board (32). The circuit board (32) is also provided with a main control chip IC2. The main control chip IC2 is electrically connected to the switching power supply circuit, the first load, and the second load respectively to control the working state of the corresponding circuits. The output terminal of the first output unit (11) is electrically connected to the power supply terminal of the first load, and the output terminal of the second output unit (12) is electrically connected to the power supply terminal of the second load.

7. The electrical appliance according to claim 6, characterized in that: The first load is a DC motor, and the second load is an LED module.

8. The electrical appliance according to claim 7, characterized in that: It also includes a relay module (31), the power supply terminal of which is electrically connected to the output terminal of the first output unit (11), the main control chip IC2 is electrically connected to the input terminal of the relay module (31), and the output terminal of the relay module (31) is electrically connected to the first load and the second load respectively to control the working state of the corresponding load.

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