Doorbell AC power supply circuit and doorbell control method thereof

Abstract

The invention discloses a doorbell AC power supply circuit and a doorbell control method thereof. The doorbell AC power supply circuit comprises a control unit, an AC interface, an AC rectification and protection circuit, a short-circuit circuit, an AC judgment circuit, a DC-DC circuit, a battery charging circuit and a doorbell detection circuit. The corresponding end of the control unit is electrically connected with the corresponding ends of the short-circuit circuit, the AC judgment circuit, the DC-DC circuit and the doorbell detection circuit. The corresponding end of the AC rectification and protection circuit is electrically connected with the corresponding ends of the AC interface, the short circuit, the AC judgment circuit and the DC-DC circuit, and the corresponding end of the DC-DC circuit is also connected with the battery charging circuit. Through the efficient AC rectification and protection circuit and the DC-DC circuit, the system can convert an unstable AC power supply into a stable low-voltage DC power supply, and it is ensured that the doorbell system can stably operate under various power supply conditions.

Description

Technical Field

[0001] The invention relates to the technical field of doorbell power supply, and in particular to a doorbell AC power supply circuit and a doorbell control method thereof. Background Art

[0002] Traditional doorbell systems typically rely on a direct connection to an AC power source, which works fine when the power is stable, but can affect the functionality of the doorbell when the power is unstable or interrupted. In addition, many existing doorbell systems lack effective battery backup capabilities and cannot maintain normal operation during power failures. For systems that include traditional mechanical doorbells, their responsiveness will be significantly reduced when the power supply is unstable. With the popularity of smart home systems, the efficiency and reliability requirements of doorbell systems are getting higher and higher, and a doorbell power supply and charging system that can work stably under various power conditions is needed.

[0003] In the existing doorbell power supply system design, the circuit is usually complex, the control logic is complex, the system function is single, and there are deficiencies in handling AC power short circuit and battery charging. For example, some systems may not be able to protect the circuit safety when the AC power is short-circuited, or cannot provide constant current and constant voltage when charging the battery, which may cause battery performance degradation and shortened service life. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a doorbell AC power supply circuit and a control method thereof.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] The present invention provides a doorbell AC power supply circuit, comprising: a control unit, an AC interface, an AC rectification and protection circuit, a short circuit circuit, an AC judgment circuit, a DC-DC circuit, a battery charging circuit, and a doorbell detection circuit;

[0007] The corresponding ends of the control unit are electrically connected to the corresponding ends of the short-circuit circuit, the AC judgment circuit, the DC-DC circuit, and the doorbell detection circuit respectively;

[0008] The corresponding ends of the AC rectification and protection circuit are electrically connected to the AC interface, the short circuit circuit, the AC judgment circuit, and the corresponding ends of the DC-DC circuit respectively, and the corresponding ends of the DC-DC circuit are also connected to the battery charging circuit;

[0009] The AC interface is used for AC power access;

[0010] The AC rectification and protection circuit is used to convert the input AC power into a stable DC power;

[0011] The short-circuit circuit is used to short-circuit the AC power supply to support the doorbell ringing operation;

[0012] The AC judgment circuit is used to detect the AC power supply status;

[0013] The DC-DC circuit is used to convert the high voltage power input by the AC rectification and protection circuit into a low voltage usable power supply;

[0014] The battery charging circuit is used to convert the available power into a constant current and constant voltage power supply for the lithium battery;

[0015] The doorbell detection circuit is used to detect the doorbell key command.

[0016] Preferably, the doorbell AC power supply circuit also includes a connector, and corresponding ends of the connector are electrically connected to corresponding ends of a DC-DC circuit and a battery charging circuit respectively; and the control unit is set to be an MCU.

[0017] Preferably, the AC rectification and protection circuit is composed of an AC input access and protection circuit, an AC rectification circuit, and an input voltage stabilization circuit;

[0018] The AC input access and protection circuit includes a primary protection circuit, a diode protection circuit, and a common mode protection circuit, wherein the primary protection circuit includes a fuse F1 and a varistor RV1; the diode protection circuit is composed of a fuse F2, a diode ESD1, a diode D11, and a diode ESD2; the common mode protection circuit is composed of a magnetic bead R1, a magnetic bead R2, and a common mode inductor L5;

[0019] The AC rectifier circuit includes a rectifier diode VD1;

[0020] The input voltage stabilizing circuit includes capacitor C1, capacitor C30, capacitor C31, capacitor C32, capacitor C33, capacitor C34, and capacitor C34;

[0021] The first end of the fuse F1 is connected to the negative input terminal of the AC power supply, the second end of the fuse F1 is electrically connected to the first end of the varistor RV1 and the second pin of the rectifier diode VD1, and the second end of the varistor RV1 is electrically connected to the positive input terminal of the AC power supply and the first pin of the rectifier diode VD1;

[0022] The third pin of the rectifier diode VD1 is electrically connected to the first end of the diode ESD1 and the fuse F2 respectively, and the fourth pin of the rectifier diode VD1 is electrically connected to the second end of the diode ESD1 and the first end of the diode D11 respectively;

[0023] The second end of the fuse F2 is electrically connected to the first end of the magnetic bead R1 and the fourth pin of the common mode inductor L5, and the second end of the diode D11 is electrically connected to the first end of the magnetic bead R2 and the first pin of the common mode inductor L5;

[0024] The second end of the magnetic bead R1 is electrically connected to the third pin of the common-mode inductor L5, the capacitor C1, the diode ESD2, the capacitor C30, the capacitor C31, the capacitor C32, the capacitor C33, the capacitor C34, and the first end of the capacitor C34; the second end of the magnetic bead R2 is electrically connected to the second pin of the common-mode inductor L5, the capacitor C1, the diode ESD2, the capacitor C30, the capacitor C31, the capacitor C32, the capacitor C33, the capacitor C34, and the second end of the capacitor C34.

[0025] Preferably, the DC-DC circuit includes a power chip U1, a resistor R4, a resistor R5, a resistor R7, a resistor R9, a resistor R11, a resistor R47, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a capacitor C8, a capacitor C9, a capacitor C10, a capacitor C11, a diode D3, and an inductor L3;

[0026] The first pin of the power chip U1 is electrically connected to the first ends of the capacitor C2, the diode D3, and the inductor L3 respectively; the second end of the capacitor C2 is electrically connected to the eighth pin of the power chip U1, and the second end of the diode D3 is grounded; the second end of the inductor L3 is electrically connected to the first ends of the capacitor C4, the capacitor C7, the capacitor C3, the resistor R5, and the capacitor C8 respectively;

[0027] The fourth pin of the power chip U1 is electrically connected to the first end of the resistor R7, the second end of the resistor R5, and the second end of the capacitor C8, respectively, and the second end of the resistor R7 is grounded;

[0028] The third pin of the power chip U1 is electrically connected to the first ends of the capacitor C10, the capacitor C11, and the resistor R11 respectively, the second ends of the capacitor C10 and the capacitor C11 are grounded, and the second end of the resistor R11 is electrically connected to the input voltage AC_DC_5V_F terminal;

[0029] The 7th pin of the power chip U1 is electrically connected to the first end of the resistor R4, the capacitor C6, and the capacitor C5 respectively. The second end of the resistor R4 is electrically connected to the DC_VIN_CTRL signal end, the first end of the resistor R47, the 2nd pin of the power chip U1, and the first end of the capacitor C9 respectively. The second end of the capacitor C9 is electrically connected to the second end of the resistor R47 and is grounded. The second ends of the capacitor C6 and the capacitor C5 are both grounded. The 6th pin of the power chip U1 is grounded via the resistor R9.

[0030] Preferably, the short circuit includes a diode D6, a diode D10, a resistor R3, a resistor R12, a resistor R39, a resistor R53, a MOS tube Q1, and a MOS tube Q3;

[0031] The drain of the MOS tube Q1 is electrically connected to the first end of the resistor R3 and the diode D10 respectively, and the gate of the MOS tube Q1 is electrically connected to the first end of the resistor R39, the resistor R3, and the second end of the diode D10 respectively through the resistor R53; the second end of the resistor R39 is electrically connected to the source of the MOS tube Q3, the gate of the MOS tube Q3 is electrically connected to the first end of the resistor R12 and the diode D6 respectively, the drain of the MOS tube Q1 is electrically connected to the second end of the resistor R12; the second end of the diode D6 is connected to the MC_TIME_CTRL signal end.

[0032] Preferably, the AC judgment circuit includes a comparator circuit and a voltage stabilizing circuit electrically connected to a corresponding end of the comparator circuit;

[0033] The voltage stabilizing circuit includes a capacitor C17, a capacitor C18, a resistor R54, and a voltage stabilizing chip U8, wherein the first pin of the voltage stabilizing chip U8 is electrically connected to the first ends of the capacitors C17 and C18, respectively, the second pin of the voltage stabilizing chip U8 is electrically connected to the second end of the capacitor C17, and the third pin of the voltage stabilizing chip U8 is electrically connected to the first end of the resistor R54, the second end of the capacitor C18, and the corresponding end of the comparator circuit, respectively;

[0034] The comparator circuit includes a comparator chip U19, a resistor R24, a resistor R25, a resistor R26, a resistor R27, a resistor R29, a resistor R33, a resistor R41, a resistor R42, a resistor R51, a capacitor C16, and a capacitor C19; the first pin of the comparator chip U19 is electrically connected to the first ends of the resistor R29, the resistor R33, and the capacitor C16, respectively, and the second end of the resistor R33 is electrically connected to the second end of the capacitor C16 and is grounded;

[0035] The third pin of the comparator chip U19 is electrically connected to the first ends of the resistors R41 and R42 respectively, the second ends of the resistors R41 are electrically connected to the first ends of the resistors R25, C19 and R24 respectively, the second ends of the resistors R25 are electrically connected to the second pin of the comparator chip U19 and the second end of the capacitor C19 respectively, the second ends of the resistors R42 are electrically connected to the fourth pin of the comparator chip U19, the resistors R26 and the first ends of the resistors R51 respectively, the second ends of the resistors R26 are electrically connected to the fifth pin of the comparator chip U19, and the second ends of the resistors R51 are grounded via resistors R27.

[0036] Preferably, the battery charging circuit includes a charging constant current circuit and a measuring constant voltage circuit;

[0037] The charging constant current circuit includes a constant current charging chip U2, a resistor R34, a resistor R35, a resistor R36, a resistor R37, a diode D9, a MOS tube Q6, a capacitor C22, a capacitor C23, a capacitor C24, a capacitor C25, a capacitor C26, and an inductor L4; the first pin of the constant current charging chip U2 is electrically connected to the first end of the resistor R34, the inductor L4, and the capacitor C22, respectively, the second end of the capacitor C22 is electrically connected to the first end of the resistor R35 and the ninth pin of the constant current charging chip U2, the second end of the resistor R35 is electrically connected to the second end of the resistor R34 and the fifth pin of the constant current charging chip U2, the second end of the inductor L4 is electrically connected to the third pin of the constant current charging chip U2 and the first end of the diode D9, and the second end of the diode D9 is electrically connected to the The first end of the capacitor C23 and the drain of the MOS tube Q6 are electrically connected, the second end of the capacitor C23 is grounded, the gate of the MOS tube Q6 is electrically connected to the 8th pin of the constant current charging chip U2 and the first end of the capacitor C24 respectively, the second end of the capacitor C24 is grounded, the source of the MOS tube Q6 is electrically connected to the 6th pin of the constant current charging chip U2 and the first end of the resistor R36 respectively; the second end of the resistor R36 is electrically connected to the 7th pin of the constant current charging chip U2 and the first end of the capacitor C25 respectively, and the second end of the capacitor C25 is grounded; the 2nd pin of the constant current charging chip U2 is electrically connected to the first end of the resistor R37 and the capacitor C26 respectively; the second end of the resistor R37 is electrically connected to the 4th pin of the constant current charging chip U2, and the second end of the capacitor C26 is grounded;

[0038] The constant voltage measurement circuit includes a constant voltage charging chip U20, a capacitor C20, a capacitor C21, and a capacitor C36; the first pin of the constant voltage charging chip U20 is electrically connected to the first ends of the capacitors C20, C21, and C36, respectively, the second pin of the constant voltage charging chip U20 is electrically connected to the second ends of the capacitors C20 and C36, respectively, and the third pin of the constant voltage charging chip U20 is electrically connected to the second end of the capacitor C22.

[0039] Preferably, the doorbell detection circuit includes a resistor R20, a diode D4, a switch SW1, and a capacitor C15; the first end of the resistor R20 is electrically connected to the RST_KEY signal end and the first end of the capacitor C15, respectively, and the second end of the resistor R20 is electrically connected to the first end of the diode D4 and the corresponding end of the switch SW1, respectively; the second ends of the capacitor C15 and the diode D4 are both grounded.

[0040] The present invention also provides a doorbell control method of the doorbell AC power supply circuit, comprising the following steps:

[0041] Step S1: Detecting the AC power supply, and converting the AC power supply into a DC power supply through an AC rectification and protection circuit;

[0042] Step S2: Detecting the AC power supply status through the AC judgment circuit and outputting a corresponding signal to the control unit;

[0043] Step S3: The control unit controls the on and off of the high-voltage DC-DC circuit according to the signal of the AC judgment circuit;

[0044] Step S4: When the AC power supply is short-circuited, the AC power supply is short-circuited through a short-circuit circuit to support the operation of a traditional mechanical doorbell;

[0045] Step S5: When the AC power supply is stable, the battery charging circuit provides constant current and constant voltage charging for the lithium battery.

[0046] Preferably, in step S1, the power supply is converted into a DC voltage through the rectifier diode VD1 and the capacitors C1, C30, C31, C32, C33 and C34 of the input voltage stabilization circuit; in step S2, the control unit detects the edge trigger signal of the RST_KEY pin of the doorbell detection circuit; in step S3, the MCU pulls the AC_DC_CTRL signal from a high level to a low level, and turns off the high-voltage DC-DC circuit that supplies power to the subsequent system through AC. In step S3, after 300ms, the MC_TIME_CTRL signal of the AC short-circuit circuit turns on the MOS tube Q1, realizes AC short circuit, turns on the external mechanical doorbell, and the AC supply to the subsequent circuit is continuously disconnected; in step S4, the AC_DC_CTRL signal end and the MC_TIME_CTRL signal end are continuously at a low level for 1000ms and then released to a high level, and the AC only charges the battery but does not supply power to the subsequent stage, and resumes normal power supply and charging state after 1000ms.

[0047] The technical solution of the present invention has the following beneficial effects:

[0048] The present invention can adapt to a wide range of AC power input (10-24VAC), and can ensure the normal operation of the doorbell even under conditions of unstable power or poor quality, thereby improving the applicability and reliability of the system, and can maintain power supply from multiple power systems, without the need to charge the battery specifically after connecting to AC; through efficient AC rectification and protection circuits and DC-DC circuits, the system can convert unstable AC power into stable low-voltage DC power, ensuring that the doorbell system can operate stably under various power conditions.

[0049] Efficient battery charging management: The battery charging circuit adopts constant current and constant voltage charging method to ensure that the lithium battery is neither overcharged nor undercharged during the charging process, thereby improving the battery life and charging efficiency.

[0050] Compatible with traditional and modern doorbells: Through the design of the short-circuit circuit, the system is able to support the operation of traditional mechanical doorbells when the AC power is shorted, while maintaining compatibility with modern electronic doorbells.

[0051] Fast-response doorbell detection: The doorbell detection circuit can quickly respond to the user's bell action and notify the MCU in time to ensure fast response of the doorbell and improve user experience.

[0052] Optimized power management logic: The MCU intelligently controls the on and off of the high-voltage DC-DC circuit according to the signal of the AC judgment circuit, optimizes the power management logic, and reduces unnecessary energy consumption.

[0053] Enhanced system safety: The AC detection circuit can output a signal to the MCU in time when abnormal power conditions are detected, triggering protection measures to protect the entire doorbell system from damage.

[0054] The present invention integrates AC rectification and protection circuit, short circuit circuit, AC judgment circuit, DC-DC circuit, battery charging circuit and doorbell detection circuit. The present design simplifies the circuit structure, reduces the number of components, and reduces cost and complexity.

[0055] Efficient battery management: The battery charging circuit adopts constant current and constant voltage charging method to effectively manage the battery charging process, extend the battery life, and ensure that the battery can provide stable power when needed.

[0056] Support for traditional doorbell operation: Through the design of the short-circuit circuit, the system can support the operation of traditional mechanical doorbells when the AC power is short-circuited, maintaining compatibility with old systems.

[0057] Improved user experience: The system can automatically switch to battery power when power is unstable or interrupted, ensuring the doorbell's continued response, thereby improving the user experience.

[0058] Reliable power judgment and protection: The AC judgment circuit can accurately monitor the power status and promptly output a signal to the MCU when an unstable power supply is detected, triggering protection measures to protect the system from damage.

[0059] Easy to maintain and upgrade: The modular design of the system makes maintenance and upgrade easier, reduces maintenance costs and improves system scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a circuit control block diagram of the present invention;

[0061] Figure 2 The circuit schematic diagram of the AC to DC rectification and protection circuit of the present invention;

[0062] Figure 3 is a circuit schematic diagram of the AC short circuit of the present invention;

[0063] Figure 4 is a circuit schematic diagram of a DC-DC circuit of the present invention;

[0064] Figure 5 A circuit schematic diagram of a battery charging circuit of the present invention;

[0065] Figure 6 is a circuit schematic diagram of the AC judgment circuit of the present invention;

[0066] Figure 7 is a circuit schematic diagram of a doorbell detection circuit of the present invention;

[0067] Figure 8 This is a connection diagram of the circuit of the present invention when it is externally connected to a traditional mechanical doorbell;

[0068] Fig. 9 It is a schematic diagram of the detection control timing of the present invention. DETAILED DESCRIPTION

[0069] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0070] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0071] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0072] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0074] Reference Figures 1 to 9 The present invention provides a doorbell AC power supply circuit, including: a control unit 600, an AC interface 100, an AC rectification and protection circuit 200, a short circuit circuit 300, an AC judgment circuit 700, a DC-DC circuit 400, a battery charging circuit 500, and a doorbell detection circuit 800;

[0075] The corresponding ends of the control unit 600 are electrically connected to the corresponding ends of the short circuit 300, the AC judgment circuit 700, the DC-DC circuit 800, and the doorbell detection circuit 800 respectively;

[0076] The corresponding ends of the AC rectification and protection circuit 200 are electrically connected to the corresponding ends of the AC interface 100, the short circuit circuit 300, the AC judgment circuit 700, and the DC-DC circuit 400, respectively. The corresponding end of the DC-DC circuit 400 is also connected to the battery charging circuit 500;

[0077] The AC interface 100 is used for AC power supply access;

[0078] The AC rectification and protection circuit 700 is used to convert the input AC power into a stable DC power;

[0079] The short-circuit circuit 300 is used to short-circuit the AC power supply to support the doorbell ringing operation;

[0080] The AC determination circuit 700 is used to detect the AC power supply status;

[0081] The DC-DC circuit 400 is used to convert the high voltage power input by the AC rectification and protection circuit 300 into a low voltage usable power;

[0082] The battery charging circuit 500 is used to convert the available power into a constant current and constant voltage power supply for the lithium battery;

[0083] The doorbell detection circuit 800 is used to detect doorbell key commands.

[0084] Further. The doorbell AC power supply circuit also includes a connector 900, and the corresponding ends of the connector 900 are electrically connected to the corresponding ends of the DC-DC circuit 400 and the battery charging circuit 500 respectively. The control unit 600 is an MCU, wherein the connector 900: as a connection point between the internal circuits of the system, the connector 900 allows the outputs of the DC-DC circuit 400 and the battery charging circuit 500 to be flexibly connected to other system components. This design improves the scalability and adaptability of the system, making the circuit design more modular and easy to maintain and upgrade. The microcontroller (MCU) serves as the control unit 600: the MCU is the core control unit of the system, responsible for coordinating the work of each circuit, including the AC interface 100, the AC rectification and protection circuit 200, the short circuit circuit 300, the AC judgment circuit 700, the DC-DC circuit 400, the battery charging circuit 500 and the doorbell detection circuit 800. The intelligent control logic of the MCU improves the efficiency and response speed of the system, while also reducing energy consumption.

[0085] Reference Figure 2 , the AC rectification and protection circuit 200 is composed of an AC input access and protection circuit, an AC rectification circuit, and an input voltage stabilization circuit;

[0086] The AC input access and protection circuit includes a primary protection circuit, a diode protection circuit, and a common-mode protection circuit, wherein the primary protection circuit includes a fuse F1 and a varistor RV1, and the access method can be a connector, a wiring harness, etc. The primary protection circuit is used to cope with large current shocks and voltage fluctuations to protect the circuit from damage; the diode protection circuit is composed of a fuse F2, a diode ESD1, a diode D11, and a diode ESD2, and is used to prevent electrostatic discharge and other transient voltage shocks to ensure stable operation of the circuit; the common-mode protection circuit is composed of a magnetic bead R1, a magnetic bead R2, and a common-mode inductor L5, and is used to suppress common-mode noise, reduce electromagnetic interference, and improve circuit stability.

[0087] The AC rectifier circuit includes a rectifier diode VD1, and uses TB310 to realize the conversion of AC into DC power. It is responsible for converting AC power into pulsating direct current and providing direct current power for the subsequent input voltage stabilization circuit.

[0088] The input voltage stabilization circuit includes capacitors C1, C30, C31, C32, C33, C34, and C35, providing a minimum 400mA 9.5VAC power supply capability. Currently, 330uF+5*10uF is used; the input voltage stabilizing circuit is used to smooth the pulsating DC power after rectification and provide a stable DC power supply for subsequent circuits;

[0089] The first end of the fuse F1 is connected to the negative input terminal of the AC power supply, and the second end of the fuse F1 is electrically connected to the first end of the varistor RV1 and the second pin of the rectifier diode VD1, respectively, to ensure stable access to the power supply and disconnect the circuit by the fuse F1 in an abnormal situation to protect the system safety.

[0090] The second end of the varistor RV1 is electrically connected to the positive input end of the AC power supply and the first pin of the rectifier diode VD1, respectively, to absorb voltage fluctuations and protect the circuit from voltage shocks.

[0091] The third pin of the rectifier diode VD1 is electrically connected to the first end of the diode ESD1 and the fuse F2, respectively, and the fourth pin of the rectifier diode VD1 is electrically connected to the second end of the diode ESD1 and the first end of the diode D11, respectively, to complete the conversion from AC to DC and provide protection for subsequent circuits;

[0092] The second end of the fuse F2 is electrically connected to the first end of the magnetic bead R1 and the fourth pin of the common mode inductor L5 respectively, so as to provide further overcurrent protection and electromagnetic interference suppression for the circuit.

[0093] The second end of the diode D11 is electrically connected to the first end of the magnetic bead R2 and the first pin of the common mode inductor L5 respectively;

[0094] The second end of the magnetic bead R1 is electrically connected to the third pin of the common mode inductor L5, the capacitor C1, the diode ESD2, the capacitor C30, the capacitor C31, the capacitor C32, the capacitor C33, the capacitor C34, and the first end of the capacitor C34; the second end of the magnetic bead R2 is electrically connected to the second pin of the common mode inductor L5, the capacitor C1, the diode ESD2, the capacitor C30, the capacitor C31, the capacitor C32, the capacitor C33, the capacitor C34, and the second end of the capacitor C34. The second ends of the magnetic beads R1 and R2 are respectively connected to the common mode inductor L5, the capacitor C1 and other components to form a common mode protection circuit, which effectively reduces electromagnetic interference and improves the stability of the circuit.

[0095] Reference Figure 4, the DC-DC circuit 400 includes a power chip U1, a resistor R4, a resistor R5, a resistor R7, a resistor R9, a resistor R11, a resistor R47, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a capacitor C8, a capacitor C9, a capacitor C10, a capacitor C11, a diode D3, and an inductor L3;

[0096] The first pin of the power chip U1 is electrically connected to the first ends of the capacitor C2, the diode D3, and the inductor L3 respectively; the second end of the capacitor C2 is electrically connected to the eighth pin of the power chip U1, and the second end of the diode D3 is grounded; the second end of the inductor L3 is electrically connected to the first ends of the capacitor C4, the capacitor C7, the capacitor C3, the resistor R5, and the capacitor C8 respectively;

[0097] The fourth pin of the power chip U1 is electrically connected to the first end of the resistor R7, the second end of the resistor R5, and the second end of the capacitor C8, respectively, and the second end of the resistor R7 is grounded;

[0098] The third pin of the power chip U1 is electrically connected to the first ends of the capacitor C10, the capacitor C11, and the resistor R11 respectively, the second ends of the capacitor C10 and the capacitor C11 are grounded, and the second end of the resistor R11 is electrically connected to the input voltage AC_DC_5V_F terminal;

[0099] The 7th pin of the power chip U1 is electrically connected to the first end of the resistor R4, the capacitor C6, and the capacitor C5 respectively. The second end of the resistor R4 is electrically connected to the DC_VIN_CTRL signal end, the first end of the resistor R47, the 2nd pin of the power chip U1, and the first end of the capacitor C9 respectively. The second end of the capacitor C9 is electrically connected to the second end of the resistor R47 and is grounded. The second ends of the capacitor C6 and the capacitor C5 are both grounded. The 6th pin of the power chip U1 is grounded via the resistor R9.

[0100] In this solution, U1 is composed of JW5121 power chip, and the whole circuit meets the load capacity of 5V 1.5A. The DC-DC circuit is the key part responsible for converting the input high-voltage power supply into a low-voltage power supply suitable for the system. The design of this circuit ensures the stability of the power supply and the energy efficiency of the system. Power chip U1: As the core of the DC-DC circuit, it is responsible for controlling the voltage conversion process and ensuring the stability and adjustability of the output voltage. Resistors, capacitors and inductors: These components work together to provide filtering, stabilization and energy storage functions to ensure the quality of the output voltage.

[0101] Reference Figure 3 , the short circuit 300 includes a diode D6, a diode D10, a resistor R3, a resistor R12, a resistor R39, a resistor R53, a MOS tube Q1, and a MOS tube Q3;

[0102] The drain of the mos transistor Q1 is electrically connected to the first end of the resistor R3 and the diode D10 respectively, and the gate of the mos transistor Q1 is electrically connected to the first end of the resistor R39, the resistor R3, and the second end of the diode D10 respectively through the resistor R53; the second end of the resistor R39 is electrically connected to the source of the mos transistor Q3, the gate of the mos transistor Q3 is electrically connected to the first end of the resistor R12 and the diode D6 respectively, and the drain of the mos transistor Q1 is electrically connected to the second end of the resistor R12; the second end of the diode D6 is connected to the MC_TIME_CTRL signal end;

[0103] In this embodiment, the design scheme adopts DMP6180SKmos tube Q3. MCU turns on mos tube Q1 by controlling the conduction of mos tube Q3. Under normal circumstances, mos tube Q1 is turned off, and the AC only powers the system and charges the battery. The short-circuit circuit is a key component in the doorbell power supply system. It is responsible for short-circuiting the AC power supply under certain conditions to support the normal operation of the doorbell. The design of this circuit is intended to improve the flexibility of the system and user experience.

[0104] Reference Figure 6 , the AC determination circuit 700 includes a comparator circuit and a voltage stabilizing circuit electrically connected to a corresponding end of the comparator circuit;

[0105] The voltage stabilizing circuit includes a capacitor C17, a capacitor C18, a resistor R54, and a voltage stabilizing chip U8, wherein the first pin of the voltage stabilizing chip U8 is electrically connected to the first ends of the capacitors C17 and C18, respectively, the second pin of the voltage stabilizing chip U8 is electrically connected to the second end of the capacitor C17, and the third pin of the voltage stabilizing chip U8 is electrically connected to the first end of the resistor R54, the second end of the capacitor C18, and the corresponding end of the comparator circuit, respectively;

[0106] The comparator circuit includes a comparator chip U19, a resistor R24, a resistor R25, a resistor R26, a resistor R27, a resistor R29, a resistor R33, a resistor R41, a resistor R42, a resistor R51, a capacitor C16, and a capacitor C19; the first pin of the comparator chip U19 is electrically connected to the first ends of the resistor R29, the resistor R33, and the capacitor C16, respectively, and the second end of the resistor R33 is electrically connected to the second end of the capacitor C16 and is grounded;

[0107] The third pin of the comparator chip U19 is electrically connected to the first ends of the resistors R41 and R42 respectively, the second ends of the resistors R41 are electrically connected to the first ends of the resistors R25, C19 and R24 respectively, the second ends of the resistors R25 are electrically connected to the second pin of the comparator chip U19 and the second end of the capacitor C19 respectively, the second ends of the resistors R42 are electrically connected to the fourth pin of the comparator chip U19, the resistors R26 and the first ends of the resistors R51 respectively, the second ends of the resistors R26 are electrically connected to the fifth pin of the comparator chip U19, and the second ends of the resistors R51 are grounded via resistors R27.

[0108] In this embodiment, a hysteresis comparator circuit composed of U19 (model AS331A) is used. The power supply of this part is U8 (SE8650) LDO outputting 5V power to U19; the AC judgment circuit is responsible for monitoring and judging the state of the AC power supply to ensure that the system can work stably under different power supply conditions. This circuit provides accurate power supply judgment and stable power supply output through the combination of comparator circuit and voltage stabilization circuit. Voltage stabilization circuit: responsible for providing stable power supply to the comparator circuit to ensure the working stability of the comparator chip U19; comparator circuit: responsible for monitoring the state of the AC power supply and outputting corresponding signals according to the power supply state. The voltage stabilization circuit provides a stable power supply to the comparator circuit to ensure the working stability of the comparator chip U19, thereby improving the reliability of the entire AC judgment circuit. The comparator circuit can accurately monitor the state of the AC power supply, provide accurate power supply judgment for the system, and ensure that the system works stably under different power supply conditions.

[0109] Stable power judgment and output improve the system's response speed and reliability, thereby enhancing the end-user experience.

[0110] Reference Figure 5 , the battery charging circuit 500 includes a charging constant current circuit and a measuring constant voltage circuit;

[0111] The charging constant current circuit includes a constant current charging chip U2, a resistor R34, a resistor R35, a resistor R36, a resistor R37, a diode D9, a MOS tube Q6, a capacitor C22, a capacitor C23, a capacitor C24, a capacitor C25, a capacitor C26, and an inductor L4; the first pin of the constant current charging chip U2 is electrically connected to the first end of the resistor R34, the inductor L4, and the capacitor C22, respectively, and the second end of the capacitor C22 is electrically connected to the first end of the resistor R35 and the ninth pin of the constant current charging chip U2. The second end of the resistor R35 is electrically connected to the second end of the resistor R34 and the 5th pin of the constant current charging chip U2, the second end of the inductor L4 is electrically connected to the 3rd pin of the constant current charging chip U2 and the first end of the diode D9, the second end of the diode D9 is electrically connected to the first end of the capacitor C23 and the drain of the MOSFET Q6, the second end of the capacitor C23 is grounded, the gate of the MOSFET Q6 is electrically connected to the 8th pin of the constant current charging chip U2 and the first end of the capacitor C24, the second end of the capacitor C24 is grounded, the source of the MOSFET Q6 is electrically connected to the 6th pin of the constant current charging chip U2 and the first end of the resistor R36; the second end of the resistor R36 is electrically connected to the 7th pin of the constant current charging chip U2 and the first end of the capacitor C25, and the second end of the capacitor C25 is grounded; the 2nd pin of the constant current charging chip U2 is electrically connected to the first end of the resistor R37 and the capacitor C26; the second end of the resistor R37 is electrically connected to the constant current charging chip U2 The 4th pin of the capacitor C26 is electrically connected, and the second end of the capacitor C26 is grounded; the constant voltage measurement circuit includes a constant voltage charging chip U20, a capacitor C20, a capacitor C21, and a capacitor C36; the 1st pin of the constant voltage charging chip U20 is electrically connected to the first end of the capacitor C20, the capacitor C21, and the capacitor C36, respectively, the 2nd pin of the constant voltage charging chip U20 is electrically connected to the second end of the capacitor C20 and the capacitor C36, respectively, and the 3rd pin of the constant voltage charging chip U20 is electrically connected to the second end of the capacitor C22. In this embodiment, the constant current circuit mainly includes a constant current charging chip composed of U2 (model LP28400ASPF), and the size of the resistor R36 is set by I = 5mV / R36 = 5mV / 0.12 = 42mA. The constant voltage circuit uses U20 (model SE8650) to output a constant 5V voltage, and provides a stable 5V / 42mA charging power to the battery through the constant current circuit and the constant voltage circuit to ensure stable low-current charging of the system. The constant current charging circuit ensures that the battery is charged with a constant current at the initial stage of charging, which improves the charging efficiency and shortens the charging time. The constant voltage charging circuit keeps the voltage constant when the battery is nearly fully charged, prevents overcharging, and prolongs the battery life. By combining constant current and constant voltage charging, the battery charging process is optimized, and the battery efficiency and safety are improved. The design of the battery charging circuit simplifies the power management logic and reduces the complexity and cost of the system.Stable charging performance and battery management improve device reliability and user satisfaction.

[0112] Reference Figure 7 The doorbell detection circuit 800 includes a resistor R20, a diode D4, a switch SW1, and a capacitor C15; the first end of the resistor R20 is electrically connected to the RST_KEY signal end and the first end of the capacitor C15, respectively, and the second end of the resistor R20 is electrically connected to the first end of the diode D4 and the corresponding end of the switch SW1, respectively; the second ends of the capacitor C15 and the diode D4 are both grounded. The doorbell detection circuit 800 mainly implements key action detection, and identifies whether there is an external doorbell action through the change of high and low levels.

[0113] This embodiment scheme can realize the AC power input from 10-24VAC. When the voltage is sufficient, it can normally power the entire system, and charge the battery with a constant current, and can also support the traditional mechanical doorbell or electronic doorbell function; when the voltage is insufficient, the battery can be charged and the system will not be powered.

[0114] 1. When the external power supply is not connected to the traditional mechanical doorbell or electronic doorbell, the AC charging system logic design is as follows:

[0115] When the AC power supply is connected, the power supply is converted into DC voltage through the rectifier diode VD1 and the back-end capacitor C1 (330μF), capacitor C30, capacitor C31, capacitor C32, capacitor C33, and capacitor C34 (5*10μF) of the input voltage stabilization circuit, and the AC_DC_DET signal outputs high and low levels through the hysteresis comparator of U19 (model AS331A); this model will be supplied to the MCU, and the MCU uses high and low logic to determine whether the input voltage is sufficient to control the conduction and shutdown of the high-voltage DC-DC circuit U1 (model JW5121).

[0116] The reference setting voltage of U19 (model AS331A) is 5*R33 / (R29+R33)=5*2 / (2+3)=2V. The input judgment voltage is VIN*R25 / (R25+R24)=VIN*1 / (1+3.3)=0.2326*VIN. Based on the derivation

[0117]

[0118] Where VH = 2V, R24 = 3.3K, R25 = 1K, R41 = 1K, R42 = 4K, R26 = 10K, Vmin = 10.23V, converted into AC power supply is 10.23 / 1.414≈7.23VAC;

[0119] Based on derivation

[0120] Where VH = 2V, R24 = 3.3K, R25 = 1K, R41 = 1K, R42 = 4K, R26 = 10K, Vmax = 12.4V, converted to AC power supply is 12.4 / 1.414≈8.8VAC;

[0121] The detection design judgment circuit of this solution supports a range of 7.23VAC-8.8VAC. According to the product requirements, the voltage requirement is 10VAC-24VAC, which fully meets the design judgment requirements.

[0122] When the input is 10VAC, the AC voltage judgment circuit outputs a high level. After the MCU receives the high level, it sets DC_VIN_CTRL to high, and the high-voltage DC-DC output is normal 5V, which can normally power the external system. At the same time, due to the existence of AC voltage, the 5V / 42mA power is delivered to the battery through the constant current and constant voltage circuit.

[0123] When the input voltage is 7VAC, the AC voltage judgment circuit outputs a low level. After receiving the low level, the MCU sets DC_VIN_CTRL to a low level, and the high-voltage DC-DC output is 0V. The AC will not supply power to the subsequent system, but the AC can charge the battery. At this time, the system will not disconnect the battery charging circuit, and the AC can continue to charge the battery through the constant current and constant voltage circuit to ensure that the battery will not be completely consumed due to use.

[0124] Reference Figure 8-Figure 7 When a traditional mechanical doorbell is connected to the system, the present invention provides a doorbell control method of the doorbell AC power supply circuit, comprising the following steps:

[0125] Step S1: Detect AC power connection, and convert AC power into DC power through AC rectification and protection circuit; ensure that AC power is correctly connected. Convert AC power into DC power through AC rectification and protection circuit to provide a stable power supply basis for subsequent circuits.

[0126] Step S2: Detect the AC power supply through the AC judgment circuit and output a corresponding signal to the MCU; the AC judgment circuit monitors the stability of the power supply to ensure that the power supply is within an acceptable range. Once the unstable power supply is detected, it will output a signal to the microcontroller (MCU) so that the MCU can take corresponding measures.

[0127] Step S3: The MCU controls the on and off of the high-voltage DC-DC circuit according to the signal of the AC judgment circuit; The MCU determines the power supply state according to the signal of the AC judgment circuit and controls the on and off of the high-voltage DC-DC circuit. When the power supply is stable, the DC-DC circuit is allowed to work and convert the high-voltage DC power supply into a low-voltage power supply suitable for the system.

[0128] Step S4: When the AC power supply is short-circuited, the AC power supply is short-circuited through the short-circuit circuit to support the operation of the traditional mechanical doorbell; when the user operates the doorbell, the short-circuit circuit will short-circuit the AC power supply in a short time to support the operation of the traditional mechanical doorbell. This step ensures that the doorbell can work normally even when the power supply is unstable.

[0129] Step S5: When the AC power supply is stable, the battery charging circuit provides constant current and constant voltage charging for the lithium battery. The battery charging circuit is activated when the power supply is stable to provide constant current and constant voltage charging for the lithium battery. This ensures that the battery can be charged safely and efficiently, while extending the battery life.

[0130] When AC power is connected to the system, it is first processed by the AC rectification and protection circuit. This circuit includes primary protection, AC rectification and input voltage regulation circuit to ensure the stability and safety of the power supply.

[0131] The AC judgment circuit monitors the status of the rectified power supply and outputs the judgment results in the form of signals to the microcontroller (MCU). The MCU determines whether the power supply is stable and whether the battery needs to be started based on these signals. According to the control signal of the MCU, the high-voltage DC-DC circuit converts the rectified high-voltage DC power supply into a low-voltage DC power supply suitable for the doorbell system, ensuring the stability of the power supply and the reliable operation of the system.

[0132] When the AC power supply is stable, the battery charging circuit charges the lithium battery through a constant current and constant voltage method, ensuring that the battery is charged under safe and efficient conditions and extending the battery life.

[0133] In the event of an AC power short, the short circuit is activated, allowing the AC power to directly power the doorbell system while supporting the operation of a traditional mechanical doorbell.

[0134] The doorbell detection circuit monitors the status of the doorbell button. When the user presses the doorbell button, the circuit detects this action and triggers the MCU to process. The MCU then controls the corresponding circuit to respond to the user's operation.

[0135] In the event of unstable or interrupted power supply, the MCU control system switches to battery power supply to ensure the continuous operation of the doorbell system. At the same time, the system will activate the protection mechanism to prevent damage to the system caused by unstable power supply.

[0136] Through multiple steps of detection and control, the system can work stably under different power conditions, improving overall reliability. The system can quickly respond to user operations, whether through mechanical doorbells or electronic doorbells, and provide instant feedback; the constant current and constant voltage charging method ensures effective charging of the battery, avoids overcharging and over-discharging, and extends the battery life; the modular design of the system makes maintenance and troubleshooting easier and reduces maintenance costs. Through precise power management and control, the system reduces energy loss and improves energy efficiency.

[0137] Further, in step S1, the power supply is converted into a DC voltage through the rectifier diode VD1 and the capacitors C1, C30, C31, C32, C33 and C34 of the input voltage stabilization circuit; in step S2, the MCU detects the edge trigger signal of the RST_KEY pin of the doorbell detection circuit; in step S3, the MCU pulls the AC_DC_CTRL signal from a high level to a low level, turns off the high-voltage DC-DC circuit that powers the subsequent system with AC, and in step S3, after 300ms, the MC_TIME_CTRL signal of the AC short-circuit circuit turns on the MOS tube Q1, realizes AC short circuit, turns on the external mechanical doorbell, and the AC supply to the subsequent circuit will be continuously disconnected; in step S4, the AC_DC_CTRL signal end and the MC_TIME_CTRL signal end are continuously at a low level for 1000ms and then released to a high level, and the AC only charges the battery but does not power the subsequent stage, and resumes normal power supply and charging status after 1000ms.

[0138] This solution turns on the MOS tube Q1 by implementing circuit control, disconnects the entire back-end system, and turns on the external mechanical doorbell. To avoid repeated actions and anti-shake functions, it is set that there will only be one action of pressing the doorbell within 1S, and the mechanical doorbell will only make a "ding dong" sound. During this control process, the system will turn off the entire AC power supply to the system to ensure the safety and reliability of the entire system. When the AC power supply is turned off, there will be batteries or other power supply equipment to power the system.

[0139] It can be seen from the above embodiments that the present invention can adapt to a wide range of AC power input (10-24VAC), and can ensure the normal operation of the doorbell even under conditions of unstable power or poor quality, thereby improving the applicability and reliability of the system, and can maintain power supply from multiple power systems, without the need to charge the battery specifically after connecting to AC; through efficient AC rectification and protection circuits and DC-DC circuits, the system can convert unstable AC power into stable low-voltage DC power, ensuring that the doorbell system can operate stably under various power conditions.

[0140] Efficient battery charging management: The battery charging circuit adopts constant current and constant voltage charging method to ensure that the lithium battery is neither overcharged nor undercharged during the charging process, thereby improving the battery life and charging efficiency.

[0141] Compatible with traditional and modern doorbells: Through the design of the short-circuit circuit, the system is able to support the operation of traditional mechanical doorbells when the AC power is shorted, while maintaining compatibility with modern electronic doorbells.

[0142] Fast-response doorbell detection: The doorbell detection circuit can quickly respond to the user's bell action and notify the MCU in time to ensure fast response of the doorbell and improve user experience.

[0143] Optimized power management logic: The MCU intelligently controls the on and off of the high-voltage DC-DC circuit according to the signal of the AC judgment circuit, optimizes the power management logic, and reduces unnecessary energy consumption.

[0144] Enhanced system safety: The AC detection circuit can output a signal to the MCU in time when abnormal power conditions are detected, triggering protection measures to protect the entire doorbell system from damage.

[0145] The present invention integrates AC rectification and protection circuit, short circuit circuit, AC judgment circuit, DC-DC circuit, battery charging circuit and doorbell detection circuit. The present design simplifies the circuit structure, reduces the number of components, and reduces cost and complexity.

[0146] Efficient battery management: The battery charging circuit adopts constant current and constant voltage charging method to effectively manage the battery charging process, extend the battery life, and ensure that the battery can provide stable power when needed.

[0147] Support for traditional doorbell operation: Through the design of the short-circuit circuit, the system can support the operation of traditional mechanical doorbells when the AC power is short-circuited, maintaining compatibility with old systems.

[0148] Improved user experience: The system can automatically switch to battery power when power is unstable or interrupted, ensuring the doorbell's continued response, thereby improving the user experience.

[0149] Reliable power judgment and protection: The AC judgment circuit can accurately monitor the power status and promptly output a signal to the MCU when an unstable power supply is detected, triggering protection measures to protect the system from damage.

[0150] Easy to maintain and upgrade: The modular design of the system makes maintenance and upgrade easier, reduces maintenance costs and improves system scalability.

[0151] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A doorbell AC power supply circuit, characterized in that: include: Control unit, AC interface, AC rectification and protection circuit, short circuit circuit, AC judgment circuit, DC-DC circuit, battery charging circuit, doorbell detection circuit; The corresponding ends of the control unit are electrically connected to the corresponding ends of the short-circuit circuit, the AC judgment circuit, the DC-DC circuit, and the doorbell detection circuit respectively; The corresponding ends of the AC rectification and protection circuit are electrically connected to the AC interface, the short circuit circuit, the AC judgment circuit, and the corresponding ends of the DC-DC circuit respectively, and the corresponding ends of the DC-DC circuit are also connected to the battery charging circuit; The AC interface is used for AC power access; The AC rectification and protection circuit is used to convert the input AC power into a stable DC power; The short-circuit circuit is used to short-circuit the AC power supply to support the doorbell ringing operation; The AC judgment circuit is used to detect the AC power supply status; The DC-DC circuit is used to convert the high voltage power input by the AC rectification and protection circuit into a low voltage usable power supply; The battery charging circuit is used to convert the available power into a constant current and constant voltage power supply for the lithium battery; The doorbell detection circuit is used to detect the doorbell key command.

2. The doorbell AC power supply circuit according to claim 1, characterized in that: The doorbell AC power supply circuit also includes a connector, and corresponding ends of the connector are electrically connected to corresponding ends of a DC-DC circuit and a battery charging circuit respectively; the control unit is set to an MCU.

3. The doorbell AC power supply circuit according to claim 2, characterized in that: The AC rectification and protection circuit is composed of an AC input access and protection circuit, an AC rectification circuit, and an input voltage stabilization circuit; The AC input access and protection circuit includes a primary protection circuit, a diode protection circuit, and a common mode protection circuit, wherein the primary protection circuit includes a fuse F1 and a varistor RV1; the diode protection circuit is composed of a fuse F2, a diode ESD1, a diode D11, and a diode ESD2; the common mode protection circuit is composed of a magnetic bead R1, a magnetic bead R2, and a common mode inductor L5; The AC rectifier circuit includes a rectifier diode VD1; The input voltage stabilizing circuit includes capacitor C1, capacitor C30, capacitor C31, capacitor C32, capacitor C33, capacitor C34, and capacitor C34; The first end of the fuse F1 is connected to the negative input terminal of the AC power supply, the second end of the fuse F1 is electrically connected to the first end of the varistor RV1 and the second pin of the rectifier diode VD1, and the second end of the varistor RV1 is electrically connected to the positive input terminal of the AC power supply and the first pin of the rectifier diode VD1; The third pin of the rectifier diode VD1 is electrically connected to the first end of the diode ESD1 and the fuse F2 respectively, and the fourth pin of the rectifier diode VD1 is electrically connected to the second end of the diode ESD1 and the first end of the diode D11 respectively; The second end of the fuse F2 is electrically connected to the first end of the magnetic bead R1 and the fourth pin of the common mode inductor L5, and the second end of the diode D11 is electrically connected to the first end of the magnetic bead R2 and the first pin of the common mode inductor L5; The second end of the magnetic bead R1 is electrically connected to the third pin of the common-mode inductor L5, the capacitor C1, the diode ESD2, the capacitor C30, the capacitor C31, the capacitor C32, the capacitor C33, the capacitor C34, and the first end of the capacitor C34; the second end of the magnetic bead R2 is electrically connected to the second pin of the common-mode inductor L5, the capacitor C1, the diode ESD2, the capacitor C30, the capacitor C31, the capacitor C32, the capacitor C33, the capacitor C34, and the second end of the capacitor C34.

4. The doorbell AC power supply circuit according to claim 3, characterized in that: The DC-DC circuit includes a power chip U1, a resistor R4, a resistor R5, a resistor R7, a resistor R9, a resistor R11, a resistor R47, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a capacitor C8, a capacitor C9, a capacitor C10, a capacitor C11, a diode D3, and an inductor L3; The first pin of the power chip U1 is electrically connected to the first ends of the capacitor C2, the diode D3, and the inductor L3 respectively; the second end of the capacitor C2 is electrically connected to the eighth pin of the power chip U1, and the second end of the diode D3 is grounded; the second end of the inductor L3 is electrically connected to the first ends of the capacitor C4, the capacitor C7, the capacitor C3, the resistor R5, and the capacitor C8 respectively; The fourth pin of the power chip U1 is electrically connected to the first end of the resistor R7, the second end of the resistor R5, and the second end of the capacitor C8, respectively, and the second end of the resistor R7 is grounded; The third pin of the power chip U1 is electrically connected to the first ends of the capacitor C10, the capacitor C11, and the resistor R11 respectively, the second ends of the capacitor C10 and the capacitor C11 are grounded, and the second end of the resistor R11 is electrically connected to the input voltage AC_DC_5V_F terminal; The 7th pin of the power chip U1 is electrically connected to the first end of the resistor R4, the capacitor C6, and the capacitor C5 respectively. The second end of the resistor R4 is electrically connected to the DC_VIN_CTRL signal end, the first end of the resistor R47, the 2nd pin of the power chip U1, and the first end of the capacitor C9 respectively. The second end of the capacitor C9 is electrically connected to the second end of the resistor R47 and is grounded. The second ends of the capacitor C6 and the capacitor C5 are both grounded. The 6th pin of the power chip U1 is grounded via the resistor R9.

5. The doorbell AC power supply circuit according to claim 4, characterized in that: The short circuit includes a diode D6, a diode D10, a resistor R3, a resistor R12, a resistor R39, a resistor R53, a MOS tube Q1, and a MOS tube Q3; The drain of the MOS tube Q1 is electrically connected to the first end of the resistor R3 and the diode D10 respectively, and the gate of the MOS tube Q1 is electrically connected to the first end of the resistor R39, the resistor R3, and the second end of the diode D10 respectively through the resistor R53; the second end of the resistor R39 is electrically connected to the source of the MOS tube Q3, the gate of the MOS tube Q3 is electrically connected to the first end of the resistor R12 and the diode D6 respectively, the drain of the MOS tube Q1 is electrically connected to the second end of the resistor R12; the second end of the diode D6 is connected to the MC_TIME_CTRL signal end.

6. The doorbell AC power supply circuit according to claim 5, characterized in that: The AC judgment circuit includes a comparator circuit and a voltage stabilizing circuit electrically connected to a corresponding end of the comparator circuit; The voltage stabilizing circuit includes a capacitor C17, a capacitor C18, a resistor R54, and a voltage stabilizing chip U8, wherein the first pin of the voltage stabilizing chip U8 is electrically connected to the first ends of the capacitors C17 and C18, respectively, the second pin of the voltage stabilizing chip U8 is electrically connected to the second end of the capacitor C17, and the third pin of the voltage stabilizing chip U8 is electrically connected to the first end of the resistor R54, the second end of the capacitor C18, and the corresponding end of the comparator circuit, respectively; The comparator circuit includes a comparator chip U19, a resistor R24, a resistor R25, a resistor R26, a resistor R27, a resistor R29, a resistor R33, a resistor R41, a resistor R42, a resistor R51, a capacitor C16, and a capacitor C19; the first pin of the comparator chip U19 is electrically connected to the first ends of the resistor R29, the resistor R33, and the capacitor C16, respectively, and the second end of the resistor R33 is electrically connected to the second end of the capacitor C16 and is grounded; The third pin of the comparator chip U19 is electrically connected to the first ends of the resistors R41 and R42 respectively, the second ends of the resistors R41 are electrically connected to the first ends of the resistors R25, C19 and R24 respectively, the second ends of the resistors R25 are electrically connected to the second pin of the comparator chip U19 and the second end of the capacitor C19 respectively, the second ends of the resistors R42 are electrically connected to the fourth pin of the comparator chip U19, the resistors R26 and the first ends of the resistors R51 respectively, the second ends of the resistors R26 are electrically connected to the fifth pin of the comparator chip U19, and the second ends of the resistors R51 are grounded via resistors R27.

7. The doorbell AC power supply circuit according to claim 6, characterized in that: The battery charging circuit includes a charging constant current circuit and a measuring constant voltage circuit; The charging constant current circuit includes a constant current charging chip U2, a resistor R34, a resistor R35, a resistor R36, a resistor R37, a diode D9, a MOS tube Q6, a capacitor C22, a capacitor C23, a capacitor C24, a capacitor C25, a capacitor C26, and an inductor L4; the first pin of the constant current charging chip U2 is electrically connected to the first end of the resistor R34, the inductor L4, and the capacitor C22, respectively, the second end of the capacitor C22 is electrically connected to the first end of the resistor R35 and the ninth pin of the constant current charging chip U2, the second end of the resistor R35 is electrically connected to the second end of the resistor R34 and the fifth pin of the constant current charging chip U2, the second end of the inductor L4 is electrically connected to the third pin of the constant current charging chip U2 and the first end of the diode D9, and the second end of the diode D9 is electrically connected to the The first end of the capacitor C23 and the drain of the MOS tube Q6 are electrically connected, the second end of the capacitor C23 is grounded, the gate of the MOS tube Q6 is electrically connected to the 8th pin of the constant current charging chip U2 and the first end of the capacitor C24 respectively, the second end of the capacitor C24 is grounded, the source of the MOS tube Q6 is electrically connected to the 6th pin of the constant current charging chip U2 and the first end of the resistor R36 respectively; the second end of the resistor R36 is electrically connected to the 7th pin of the constant current charging chip U2 and the first end of the capacitor C25 respectively, and the second end of the capacitor C25 is grounded; the 2nd pin of the constant current charging chip U2 is electrically connected to the first end of the resistor R37 and the capacitor C26 respectively; the second end of the resistor R37 is electrically connected to the 4th pin of the constant current charging chip U2, and the second end of the capacitor C26 is grounded; The constant voltage measurement circuit includes a constant voltage charging chip U20, a capacitor C20, a capacitor C21, and a capacitor C36; the first pin of the constant voltage charging chip U20 is electrically connected to the first ends of the capacitors C20, C21, and C36, respectively, the second pin of the constant voltage charging chip U20 is electrically connected to the second ends of the capacitors C20 and C36, respectively, and the third pin of the constant voltage charging chip U20 is electrically connected to the second end of the capacitor C22.

8. The doorbell AC power supply circuit according to claim 7, characterized in that: The doorbell detection circuit includes a resistor R20, a diode D4, a switch SW1, and a capacitor C15; the first end of the resistor R20 is electrically connected to the RST_KEY signal end and the first end of the capacitor C15, respectively, and the second end of the resistor R20 is electrically connected to the first end of the diode D4 and the corresponding end of the switch SW1, respectively; the second ends of the capacitor C15 and the diode D4 are both grounded.

9. A doorbell control method using the doorbell AC power supply circuit according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1: Detecting the AC power supply, and converting the AC power supply into a DC power supply through an AC rectification and protection circuit; Step S2: Detecting the AC power supply status through the AC judgment circuit and outputting a corresponding signal to the control unit; Step S3: The control unit controls the on and off of the high-voltage DC-DC circuit according to the signal of the AC judgment circuit; Step S4: When the AC power supply is short-circuited, the AC power supply is short-circuited through a short-circuit circuit to support the operation of a traditional mechanical doorbell; Step S5: When the AC power supply is stable, the battery charging circuit provides constant current and constant voltage charging for the lithium battery.

10. The doorbell control method of the doorbell AC power supply circuit according to claim 9, characterized in that: In step S1, the power supply is converted into a DC voltage through a rectifier diode VD1 and capacitors C1, C30, C31, C32, C33 and C34 of an input voltage stabilization circuit; In step S2, the control unit detects an edge trigger signal of the RST_KEY pin of the doorbell detection circuit; In step S3, the control unit pulls the AC_DC_CTRL signal from a high level to a low level, turning off the high-voltage DC-DC circuit that supplies power to the subsequent system. In step S3, after 300ms, the MC_TIME_CTRL signal of the AC short circuit turns on the MOS tube Q1, realizing the AC short circuit, turning on the external mechanical doorbell, and the AC supply to the subsequent circuit will be continuously disconnected; In step S4, the AC_DC_CTRL signal terminal and the MC_TIME_CTRL signal terminal are at a low level for 1000ms and then released to a high level, and the AC only charges the battery but does not supply power to the subsequent stage. After 1000ms, the normal power supply and charging state is restored.

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