A charger circuit with automatic on / off

Abstract

This invention provides an automatic power-on / off charger circuit, including an MCU control module, a charging control module, a power conversion module, an output current detection module, an output voltage detection module, an automatic power-on detection module, and an output port for connecting a load device. The power conversion module is connected to the input terminal of the charging control module, and the output terminal of the charging control module is connected to the input terminal of the output port. The automatic power-on detection module is connected to the output port, and its output terminal is connected to the input terminal of the MCU control module. The output current detection module detects the current in the load and circuit, and the output voltage detection module detects the charging voltage. The control terminal of the charging control module is connected to the MCU control module to control the automatic power-on / off of the charger circuit. This invention improves the safety of the charger's charging function.

Description

Technical Field

[0001] This utility model relates to the field of charger circuits, specifically to a charger circuit with automatic power on / off. Background Technology

[0002] As the battery capacity of electronic products continues to increase, the voltage and current of the charging equipment are becoming increasingly higher in order to charge the devices faster. This has led to widespread concern about the safety of these charging functions.

[0003] The following problems may occur when charging electronic products:

[0004] 1. If the charger is not unplugged after the product is fully charged, the product will remain in a charging state, which will cause the battery to overcharge.

[0005] 2. Simply unplugging the product from the charging cable after it's fully charged, without disconnecting the charger and charging cable, not only wastes energy, but also, leaving the charging cable plugged in for extended periods can attract impurities, causing micro-short circuits. This prolonged heat can eventually burn out the data cable or even cause a fire.

[0006] 3. When charging the phone, the actual charging power of the charger is unknown, or there is no indication when the charger is malfunctioning, so the charger cannot be unplugged from the AC power source in time.

[0007] The following solutions exist on the market to address these issues:

[0008] 1. Timer socket: The disadvantage of this type of socket is that it cannot adapt to the charging time of different devices.

[0009] 2. Using a fast charging chip based on a communication protocol to shut down the output has the main disadvantages of high cost and dependence on feedback from the mobile phone.

[0010] 3. The product automatically shuts down after being fully charged. The downside is that you need to unplug and plug the charger or press the button to turn it on again to recharge the product.

[0011] Therefore, it is necessary to develop a completely new charger circuit to solve the series of problems encountered above. Utility Model Content

[0012] To address the problems in the prior art, this utility model provides a charger circuit with automatic power on / off functionality.

[0013] This utility model discloses an automatic power-on / off charger circuit, comprising an MCU control module, a charging control module, a power conversion module, an output current detection module, an output voltage detection module, an automatic power-on detection module, and an output port for connecting to a load device. The input terminal of the power conversion module is connected to an external AC power source, and its output terminal is connected to the input terminal of the charging control module. The output terminal of the charging control module is connected to the input terminal of the output port. The input terminal of the automatic power-on detection module is connected to the output port, and its output terminal is connected to the input terminal of the MCU control module. The output terminal of the output current detection module is connected to the current detection terminal of the MCU control module for detecting the current in the load and circuit. The output voltage detection module is connected to the voltage detection terminal of the MCU control module for detecting the charging voltage. The control terminal of the charging control module is connected to the MCU control module for controlling the automatic power-on / off of the charger circuit.

[0014] Furthermore, it also includes a power button, which is connected to the MCU control module.

[0015] Furthermore, it also includes a status indication module, the input of which is connected to the output of the MCU control module.

[0016] Furthermore, the status indication module includes light-emitting diodes LED1, LED2, and LED3, wherein the positive terminals of LED1, LED2, and LED3 are respectively connected to a power supply, and the negative terminals are connected to different control terminals of the MCU control module. LED1, LED2, and LED3 are used to indicate different charging powers.

[0017] Furthermore, the MCU control module includes an MCU chip U6. Pin 1 of the MCU chip U6 is connected to the MCU power supply, pin 2 is connected to the output voltage detection module, pin 7 is connected to the automatic power-on detection module and the MCU power supply respectively, pin 8 is connected to the output current detection module, and pin 9 controls the power-on and power-off of the charger circuit through the charging control module.

[0018] Furthermore, the charging control module includes a first switching transistor, and the automatic power-on detection module includes a second switching transistor, a first resistor, and a second resistor. Pin 7 of the MCU chip U6 is connected to the drain of the second switching transistor, the source of the second switching transistor is grounded, and the gate is connected to one end of the first resistor and the second resistor respectively. The other end of the first resistor is grounded, and the other end of the second resistor is connected to the drain of the first switching transistor. The source of the first switching transistor is connected to the output current detection module, and the gate of the second switching transistor is connected to pin 9 of the MCU chip U6 through a third resistor.

[0019] Furthermore, the output current detection module includes a current detection resistor, a comparator U2, and a fourth resistor. One end of the current detection resistor is connected to the source of the first switching transistor, and the other end is grounded. The first input terminal and the second input terminal of the comparator U2 are respectively connected to the two ends of the current detection resistor. The output terminal of the comparator U2 is connected to pin 8 of the MCU chip U6 through the fourth resistor. When the MCU U6 detects that the current flowing through the current detection resistor is less than a set value, it automatically cuts off the power through the first switching transistor to stop charging the load. When it detects that the current flowing through the current detection resistor is greater than the set value, it automatically cuts off the power through the first switching transistor.

[0020] Furthermore, the charging control module includes a fast charging protocol chip U4, which is used to communicate with the load and adjust the output voltage and current according to the load.

[0021] Furthermore, the output voltage detection module includes a fifth resistor and a sixth resistor connected in series. One end of the fifth resistor and the sixth resistor is grounded, and the other end is connected to the voltage input terminal of the fast charging protocol chip U4. The voltage detection terminal of the MCU control module is connected between the fifth resistor and the sixth resistor.

[0022] Compared with the prior art, the advantages of this utility model are: it can not only automatically turn on and charge after the load device is plugged in, but also automatically turn off after it is fully charged, and automatically turn off when a continuous large current is detected, thereby improving the safety of the charger's charging function.

[0023] Specifically, this invention features an automatic power-on detection module. When the charger is plugged into an AC power outlet, it is powered on and can supply power to the MCU, thus enabling the MCU to power on automatically. An output current detection module effectively detects the current signal. If the current signal is less than a set value, it indicates that the load is fully charged; if it is greater than the set value, it indicates that there may be a micro-short circuit or wiring abnormality at the output port. The MCU can then automatically power off the output port through the charging control module. Through this automatic power-on / off hardware circuit design, the charger can detect and automatically shut down to disconnect the power supply, regardless of whether it is connected to a load or not, effectively improving the safety of the charger circuit.

[0024] This invention, by setting a status indicator module and cooperating with a fast charging protocol chip, can indicate different charging power or abnormal charging situations through the status indicator module, so that users can intuitively obtain the actual charging power of the charger, and can intervene and handle abnormalities in a timely manner. Attached Figure Description

[0025] To more clearly illustrate the solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a block diagram of the charger circuit structure of this utility model;

[0027] Figure 2 This is a circuit diagram of an embodiment of the power conversion module of this utility model;

[0028] Figure 3 This is a circuit schematic diagram of the fast charging protocol chip for the power conversion module feedback unit, output voltage detection module, and charging control module.

[0029] Figure 4 This is a circuit schematic diagram of the first switching transistor section of the MCU control module, output current detection module, automatic power-on detection module, and charging control module. Detailed Implementation

[0030] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, and accompanying drawings are used to distinguish different objects, not to describe a particular order.

[0031] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment to other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0032] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0033] like Figure 1As shown, the automatic power-on / off charger circuit of this utility model includes an MCU control module, a charging control module, a power conversion module, an output current detection module, an output voltage detection module, an automatic power-on detection module, and an output port. Preferably, it also includes a power-on / off button and a status indicator module.

[0034] In this example, the power conversion module's input is connected to an external AC power source, and its output is connected to the input of the charging control module. It converts AC power into a suitable charging power source to charge the downstream load device. The output of the charging control module is connected to the input of the output port, controlling the charging power of the load device and switching the output port power on or off. The output of the automatic power-on detection module is connected to the input of the MCU control module for power-on detection; when the charger is plugged into the socket, the MCU control module of the charger circuit automatically powers on. The output current detection module's output is connected to the current detection terminal of the MCU control module, detecting the current in the load and circuit. The output voltage detection module is connected to the voltage detection terminal of the MCU control module, detecting the charging voltage. The control terminal of the charging control module is connected to the MCU control module, controlling the charger circuit to automatically power on and off. The output port is used to connect an external load device for charging.

[0035] like Figure 1 and Figure 4 As shown, the input terminal of the status indicator module in this example is connected to the output terminal of the MCU control module. The status indicator module in this example can be an audio-visual indicator module. Preferably, the status indicator module in this example includes light-emitting diodes LED1, LED2, and LED3. The positive terminals of the light-emitting diodes LED1, LED2, and LED3 are respectively connected to the power supply, and the negative terminals are connected to different control terminals of the MCU control module. The light-emitting diodes LED1, LED2, and LED3 are used to indicate different charging powers.

[0036] In this example, the MCU control module includes an MCU chip U6. Pin 1 of the MCU chip U6 is connected to the MCU power supply, pin 2 is connected to the output voltage detection module, pins 3-5 are connected to the negative terminals of LEDs LED1, LED2, and LED3 respectively, pin 6 is connected to the power button KEY, pin 7 is connected to the automatic power-on detection module and the MCU power supply respectively, pin 8 is connected to the output current detection module, and pin 9 controls the power on / off of the charger circuit through the charging control module.

[0037] The charging control module in this example includes a first switching transistor, and the automatic power-on detection module includes a second switching transistor, a first resistor, and a second resistor. Pin 7 of the MCU chip U6 is connected to the drain of the second switching transistor, the source of the second switching transistor is grounded, and the gate is connected to one end of the first resistor and the second resistor respectively. The other end of the first resistor is grounded, and the other end of the second resistor is connected to the drain of the first switching transistor. The source of the first switching transistor is connected to the output current detection module, and the gate of the second switching transistor is connected to pin 9 of the MCU chip U6 through a third resistor.

[0038] The output current detection module in this example includes a current detection resistor, a comparator U2, and a fourth resistor. One end of the current detection resistor is connected to the source of the first switching transistor, and the other end is grounded. The first and second input terminals of the comparator U2 are respectively connected to the two ends of the current detection resistor. The output terminal of the comparator U2 is connected to pin 8 of the MCU chip U6 through the fourth resistor. When the MCU U6 detects that the current flowing through the current detection resistor is less than a set value, it automatically cuts off the power through the first switching transistor to stop charging the load. When it detects that the current flowing through the current detection resistor is greater than the set value, it automatically cuts off the power through the first switching transistor.

[0039] like Figure 3 As shown, the charging control module in this example includes a fast charging protocol chip U4, which is used to communicate with the load and adjust the output voltage and current according to the load, thereby enabling the charger of this invention to support fast charging.

[0040] In this example, the output voltage detection module includes a fifth resistor R9A and a sixth resistor R12A connected in series. One end of the fifth resistor R9A and the sixth resistor R12A is grounded, and the other end is connected to the voltage input terminal of the fast charging protocol chip U4. The voltage detection terminal of the MCU control module is connected between the fifth resistor R9A and the sixth resistor R12A.

[0041] like Figure 2 and Figure 3As shown, the power conversion module in this example includes an AC-to-DC unit, a DC-to-charge voltage unit, and an MCU power supply unit arranged sequentially according to the current signal. The AC-to-DC unit is implemented using a rectifier BD1 and is also equipped with a fuse F1 and a thermistor NTC1 for short-circuit and port surge protection. The DC-to-charge voltage unit is mainly implemented using a transformer T1. A PWM chip U1 is installed on the primary side of the transformer to convert the rectified DC power back into AC voltage through the control transformer. A synchronous rectifier chip U2 is installed on the secondary side to rectify the AC voltage into DC for use by the device. A voltage feedback unit is also provided at the output of the DC-to-charge voltage unit. The voltage feedback unit includes a first voltage feedback unit and a second voltage feedback unit. The first voltage feedback unit includes a series resistor R8, a resistor R10, and a three-terminal Zener diode U5. The three-terminal Zener diode U5 is a three-terminal adjustable precision parallel voltage regulator integrated circuit with its positive terminal grounded. The second voltage feedback unit includes a series resistor R9 and a resistor R12, with the other end of resistor R12 grounded. The voltage feedback unit also includes a series resistor R114 and a capacitor C8. One end of the series resistor R114 and capacitor C8 is connected between the first voltage feedback unit resistor R10 and the negative terminal of diode U5, and the other end is connected between resistor R9 and resistor R12. The third pin of the three-terminal Zener diode U5 is connected between resistor R9 and resistor R12. The output voltage can be set by an external resistor. In this example, the output voltage is 2.5*(R9 / R12+1). The voltage feedback pin 3 of the fast charging protocol chip U4 is connected between resistor R9 and resistor R12. The voltage feedback pin of chip U1 is connected to both ends of resistor R10 through the isolation optocouplers U3A / U3B. By building a circuit with multiple feedback units and the three-terminal Zener diode U5, the voltage and power supplied to external load devices can be precisely controlled.

[0042] The working principle of this utility model is as follows:

[0043] 1. When the charger is plugged into a power outlet, the MCU chip U6 initializes. At this time, the first switch Q1 is off, the second switch Q2 is off, pin 9 of the MCU chip U6 outputs a low level, pin 7 outputs a high level, and pins 2 and 8 enter the AD sampling state;

[0044] 2. When the load device is plugged into the charger, the second switch Q2 is turned on. The MCU chip U6 detects that pin 7 changes from high level to low level, indicating that a load has been plugged in for charging. Pin 9 immediately outputs a high level to turn on the first switch Q1 to charge the product.

[0045] 3. When the load device is fully charged, the current flowing through RS1 is less than the set value. The current value is obtained through the current detection circuit and the MCU's AD conversion. When the obtained value is less than the set value, Q1 will be automatically turned off to stop charging the electronic product, and preparations will be made for the next automatic power-on.

[0046] 4. When the MCU chip U6 detects a continuous large current greater than the rated current in the current sensing resistor RS1, it will compare and calculate through the comparator U2 to determine whether the excessive current is caused by a micro short circuit or abnormal wiring. The MCU chip U6 will then turn off the first switch Q1 to prevent the charging cable from burning out or catching fire.

[0047] This utility model circuit can not only automatically power on to charge the device, or automatically power off when fully charged, but also includes a power button (KEY) for powering on and a button for powering off.

[0048] 5. The MCU chip U6 calculates the charger's charging power using the voltage detected at pin 2 and the current detected at pin 8. Different power levels are indicated by different LEDs. In one embodiment of this invention, LED1 lights up for charging below 30W, LED2 lights up for 30W-65W charging, and LED3 lights up for 65W-120W charging. When there is no load device charging, all LEDs will be off. If the charger experiences a short circuit with high current or abnormal voltage, LEDs 1, 2, and 3 will flash together, indicating that the charger should be unplugged immediately to avoid fire or damage to the device.

[0049] As can be seen from the above description, this utility model can not only automatically turn on and charge after a load device is plugged in, but also automatically turn off after it is fully charged. It can also automatically turn off when a continuous high current is detected, thereby improving the safety of the charger's charging function.

[0050] This invention features an automatic power-on detection module. When the charger is plugged into an AC power outlet, it receives power and supplies power to the MCU, enabling automatic MCU power-on. An output current detection module effectively detects the current signal. If the current signal is less than a set value, it indicates the load is fully charged; if it is greater than the set value, it suggests a possible micro-short circuit or wiring malfunction at the output port. The MCU can then automatically power off the output port via the charging control module. This automatic power-on / off hardware circuit design ensures that the charger can detect and automatically shut down, disconnecting the power supply, regardless of whether a load is connected or not, effectively improving the safety of the charger circuit.

[0051] This invention, by setting a status indicator module and cooperating with a fast charging protocol chip, can indicate different charging power or abnormal charging situations through the status indicator module, so that users can intuitively obtain the actual charging power of the charger, and can intervene and handle abnormalities in a timely manner.

[0052] The specific embodiments described above are preferred embodiments of this utility model, and are not intended to limit the specific scope of this utility model. The scope of this utility model includes but is not limited to the specific embodiments described above. All equivalent changes made in accordance with this utility model are within the protection scope of this utility model.

Claims

1. An auto on / off charger circuit, characterized by: The device includes an MCU control module, a charging control module, a power conversion module, an output current detection module, an output voltage detection module, an automatic power-on detection module, and an output port for connecting to a load device. The input of the power conversion module is connected to an external AC power source, and its output is connected to the input of the charging control module. The output of the charging control module is connected to the input of the output port. The input of the automatic power-on detection module is connected to the output port, and its output is connected to the input of the MCU control module. The output of the output current detection module is connected to the current detection terminal of the MCU control module to detect the current in the load and circuit. The output voltage detection module is connected to the voltage detection terminal of the MCU control module to detect the charging voltage. The control terminal of the charging control module is connected to the MCU control module to control the automatic power-on and power-off of the charger circuit.

2. The auto-switching charger circuit of claim 1, wherein: It also includes a power button, which is connected to the MCU control module.

3. The auto-shutoff charger circuit of claim 1, wherein: It also includes a status indicator module, the input of which is connected to the output of the MCU control module.

4. The auto-switching charger circuit of claim 3, wherein: The status indication module includes light-emitting diodes LED1, LED2, and LED3. The positive terminals of LED1, LED2, and LED3 are connected to the power supply, and the negative terminals are connected to different control terminals of the MCU control module. LED1, LED2, and LED3 are used to indicate different charging powers.

5. The auto-on / off charger circuit according to any one of claims 1-3, wherein: The MCU control module includes an MCU chip U6. Pin 1 of the MCU chip U6 is connected to the MCU power supply, pin 2 is connected to the output voltage detection module, pin 7 is connected to the automatic power-on detection module and the MCU power supply respectively, pin 8 is connected to the output current detection module, and pin 9 controls the power-on and power-off of the charger circuit through the charging control module.

6. The auto-shutoff charger circuit of claim 5, wherein: The charging control module includes a first switching transistor, and the automatic power-on detection module includes a second switching transistor, a first resistor, and a second resistor. Pin 7 of the MCU chip U6 is connected to the drain of the second switching transistor, the source of the second switching transistor is grounded, and the gate is connected to one end of the first resistor and one end of the second resistor. The other end of the first resistor is grounded, and the other end of the second resistor is connected to the drain of the first switching transistor. The source of the first switching transistor is connected to the output current detection module, and the gate of the second switching transistor is connected to pin 9 of the MCU chip U6 through a third resistor.

7. The auto-shutoff charger circuit of claim 6, wherein: The output current detection module includes a current detection resistor, a comparator U2, and a fourth resistor. One end of the current detection resistor is connected to the source of the first switching transistor, and the other end is grounded. The first and second input terminals of the comparator U2 are respectively connected to the two ends of the current detection resistor. The output terminal of the comparator U2 is connected to pin 8 of the MCU chip U6 through the fourth resistor. When the MCU U6 detects that the current flowing through the current detection resistor is less than a set value, it automatically cuts off the power through the first switching transistor to stop charging the load. When it detects that the current flowing through the current detection resistor is greater than the set value, it automatically cuts off the power through the first switching transistor.

8. The auto-on / off charger circuit according to any one of claims 1-3, wherein: The charging control module includes a fast charging protocol chip U4, which is used to communicate with the load and adjust the output voltage and current according to the load.

9. The auto-shutoff charger circuit of claim 8, wherein: The output voltage detection module includes a fifth resistor and a sixth resistor connected in series. One end of the fifth resistor and the sixth resistor is grounded, and the other end is connected to the voltage input terminal of the fast charging protocol chip U4. The voltage detection terminal of the MCU control module is connected between the fifth resistor and the sixth resistor.

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