Charger

Abstract

The charger comprises a microcontroller, and a charging control execution circuit, a power supply circuit, a charging interface circuit and a charging monitoring circuit which are respectively connected with the microcontroller, the charging control execution circuit comprises a first MOS tube Q1 and a second MOS tube Q2 which are connected in series back to back, grid electrodes G of the two MOS tubes are connected and then connected with a control pin of the microcontroller, one end of the charging control execution circuit is connected with the power supply circuit, and the other end of the charging control execution circuit is connected with the charging interface circuit; a charging and power-off processing module is arranged on the microcontroller, the microcontroller converts voltage and current values obtained by the charging monitoring circuit into digital values, the charging state is judged through an automatic power-off algorithm of the charging and power-off processing module, and then the microcontroller controls the on-off state of the charging control execution circuit. According to the technical scheme of the utility model, the service lives of the electronic equipment and the battery thereof can be prolonged, the safety of the electronic equipment during charging is improved, and energy waste is reduced.

Description

Technical Field

[0001] The utility model relates to a charger. Background Art

[0002] We are now in an era where electronic devices are popular, and mobile devices have become daily necessities, such as mobile phones, computers, digital cameras, headphones, power banks, etc. These devices all use rechargeable batteries to power the devices, and their batteries usually require chargers to charge them.

[0003] Traditional chargers will continue to provide output during the charging process, that is, after the device is charged, the charger will continue to output voltage to the device, which will keep the battery fully charged for a long time. In fact, in the final stage of charging, the charging voltage is close to the critical value. Charging at this stage can easily cause some lithium ions to be over-embedded in the graphite lattice, resulting in capacity decay, so the final stage of charging has a greater impact on the cycle life. If you continue to force the battery to be fully charged with a constant current, the charging voltage will be higher, and even the positive electrode will bulge due to oxygen evolution, resulting in a decrease in battery capacity, an increase in internal resistance, and ultimately a shortened battery life. As well as the existing trickle charging, which uses trickle charging to slowly cause the last few active lithium ions to migrate to the negative electrode, it is only a compromise balance for battery protection in the final stage of charging.

[0004] There is a risk of overcharging when lithium batteries are kept fully charged for a long time. Overcharging may cause chemical reactions inside the battery, produce gas or overheat, which may lead to the risk of overheating, swelling or even explosion of the battery. It will also lead to reduced battery performance, including reduced energy density, slower charging speed, and reduced cycle life. The connection between the charger and the battery may cause slight energy loss, which may cause the charger or device to heat up. Slight heating for a long time may affect the electronic components or battery of the device, and a long-term full charge state will accelerate the chemical reaction inside the battery, causing battery aging, which will affect the device's endurance and user experience.

[0005] Therefore, in order to protect the safety and performance of lithium batteries, avoid keeping the battery fully charged for a long time. It is necessary to use a charging device with overcharge protection function to prevent potential harm caused by overcharging. Utility Model Content

[0006] The utility model aims to provide a charger which, through circuit design and charging protection control, aims to avoid damage to the device and battery caused by continued charging and prevent overcharging of the electronic device after the charging is completed.

[0007] In order to achieve the above-mentioned purpose, the utility model is specifically realized through the following technical solutions:

[0008] A charger, comprising a microcontroller and a charging control execution circuit, a power supply circuit, a charging interface circuit and a charging monitoring circuit respectively connected to the microcontroller;

[0009] The charging control execution circuit is a first MOS tube Q1 and a second MOS tube Q2 connected in series back to back, the gates G of the two MOS tubes are connected to the control pin of the microcontroller, one end of the charging control execution circuit is connected to the power circuit, and the other end is connected to the charging interface circuit;

[0010] The charging monitoring circuit is connected in parallel with the charging interface circuit, and includes a first resistor R1, a second resistor R2 and a sampling resistor RS1 connected in series, wherein the input end of the first resistor R1 is connected to one end pin of the charging interface circuit, the output end of the first resistor R1 is connected to the first sampling pin of the microcontroller and the input end of the second resistor R2; the output end of the second resistor R2 is connected to the second sampling pin of the microcontroller and is grounded; the output end of the sampling resistor RS1 is connected to the third sampling pin of the microcontroller and the other end pin of the charging interface circuit;

[0011] A charging and power-off processing module is set on the microcontroller. The microcontroller converts the voltage and current obtained by the charging monitoring circuit into digital quantities, uses the automatic power-off algorithm of the charging and power-off processing module to determine the charging power state, and then controls the on-off state of the charging control execution circuit by the microcontroller.

[0012] Further, the back-to-back series connection of the first MOS transistor Q1 and the second MOS transistor Q2 of the charging control execution circuit is: (i) the drains D of the two MOS transistors are connected, and the two sources S are respectively connected to the output end of the power circuit and the input end of the charging interface circuit; or, (ii) the sources S of the two MOS transistors are connected, and the two drains D are respectively connected to the output end of the power circuit and the input end of the charging interface circuit.

[0013] Furthermore, it also includes a warning light circuit, which includes a third resistor R3 and an LED lamp, the input end of the third resistor R3 is connected to the light control pin of the microcontroller, the output end of the third resistor R3 is connected to one end of the LED lamp, and the other end of the LED lamp is grounded.

[0014] The technical solution of the utility model can increase the service life of the electronic device and the battery thereof, improve the safety of the electronic device when charging, and reduce energy waste.

[0015] Sampling, calculation and control are performed through a microcontroller, and the anti-interference performance is effectively improved through the prediction algorithm, making the function more stable and accurate. In the charging control execution circuit, dual MOS tubes are used in series back-to-back as switches to prevent the power output voltage of the electronic device from flowing back into the charger through the body diode in the MOS tube. The circuit structure is efficient and reliable, and has the advantage of low cost. With the LED light function, it is sometimes difficult to plug in the charging cable at night, and it is not easy to reach the charger socket. In order to improve this problem, an LED ring light is added around the charger connection port, so that the charging port can be easily found in the dark. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0017] Figure 2 This is a flow chart of the automatic power-off algorithm in the utility model;

[0018] Figure 3 A power supply circuit diagram of an embodiment of the utility model;

[0019] Figure 4 It is an overall circuit diagram of an embodiment of the utility model.

[0020] In the figure, 1- microcontroller; 11- control pin; 12- first sampling pin; 13- second sampling pin; 14- third sampling pin; 15- light control pin; 2- power supply circuit; 3- charging control execution circuit; 4- charging interface circuit; 5- charging monitoring circuit; 6- charging and power-off processing module; 7- warning light circuit; 71- LED light. DETAILED DESCRIPTION

[0021] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0022] In the description of the embodiments of the present invention, it should be noted that the terms "first", "second" and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0023] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model embodiment. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0024] like Figures 1 to 4 As shown, a charger of the utility model comprises a microcontroller 1 and a power supply circuit 2, a charging control execution circuit 3, a charging interface circuit 4 and a charging monitoring circuit 5 respectively connected to the microcontroller 1;

[0025] The charging control execution circuit 3 is a first MOS transistor Q1 and a second MOS transistor Q2 connected in series back to back, the gates G of the two MOS transistors are connected to the control pin 11 of the microcontroller 1, one end of the charging control execution circuit 3 is connected to the power supply circuit 2, and the other end is connected to the charging interface circuit 4;

[0026] The charging monitoring circuit 5 is connected in parallel with the charging interface circuit 4, and includes a first resistor R1, a second resistor R2 and a sampling resistor RS1 connected in series, the input end of the first resistor R1 is connected to one end pin of the charging interface circuit 4, the output end of the first resistor R1 is connected to the first sampling pin 12 of the microcontroller 1 and the input end of the second resistor R2; the output end of the second resistor R2 is connected to the second sampling pin 13 of the microcontroller 1 and grounded; the output end of the sampling resistor RS1 is connected to the third sampling pin 14 of the microcontroller 1 and the other end pin of the charging interface circuit 4;

[0027] A charging and power-off processing module 6 is provided on the microcontroller 1. The microcontroller 1 converts the voltage and current obtained by the charging monitoring circuit 5 into digital quantities, uses the automatic power-off algorithm of the charging and power-off processing module 6 to determine the charging state, and then controls the on and off state of the charging control execution circuit 3 by the microcontroller 1.

[0028] The microcontroller 1 converts the analog values ​​of the voltage and current output by the charging into digital values ​​through the ADC (analog-to-digital converter), and obtains the charging power after multiplication. The current charging power is obtained through the automatic power-off algorithm of the charging and power-off processing module 6, and the current charging state is analyzed by combining multiple data. If the battery is fully charged, the microcontroller 1 disconnects the output voltage to the device by the charging control execution circuit 3, thereby realizing overcharge protection of the battery in the electronic device.

[0029] In some embodiments, the automatic power-off algorithm of the charging and power-off processing module 6 is as follows: after charging starts, the digital values ​​of voltage and current are obtained at a certain sampling frequency, the current charging power value is multiplied and the current charging power estimated value is calculated. If the current charging power value is greater than a first threshold value, the high-power charging stage is entered; if the current charging power value is less than a second threshold value and the current charging power estimated value is less than the second threshold value, the charging control execution circuit is controlled to be disconnected, the power output is cut off, and the charging is completed.

[0030] Based on the above scheme, preferably, the sampling frequency is 0.5 Hz-2 Hz; the first threshold is 5W; the second threshold is 3W; and the predetermined time length is 4 hours.

[0031] In some embodiments, the current charging power estimate is calculated as follows:

[0032] b2=(a*(1-x))+(b1*x),

[0033] Among them, a is the calculated current charging power value; b1 is the previous charging power estimate, and its initial value is 0; b2 is the current charging power estimate; x is the power coefficient, which is a constant, preferably 0.8, to ensure the relative accuracy of the power estimation value and to be more efficient in judging and selecting power on and off.

[0034] In some embodiments, the sampling time is 0.5s-2s; the first threshold is 5W; the second threshold is 3W; and the predetermined duration is 4h. The first threshold is greater than the second threshold. Now, devices with a charging power less than 5W (5V / 1A) are low-power charging devices. The first threshold is the threshold that defines high-power charging devices and low-power charging devices. The second threshold is used to determine the power value of the charging device after it is fully charged. The charging power of the device will become very small when it is fully charged. At this time, the power will not continue to be transmitted from the charger to the battery, but the circuit of the device will consume the power of the charger. When the device is not in use, this power will be very small, so as to determine that the charging is complete. Here, the value is 3W.

[0035] The first threshold and the second threshold can also be calculated according to the actual charging power data of current mobile devices through intelligent algorithms to obtain more reasonable and optimized values, which are stored in the memory of the MCU. As the number of uses increases, the thresholds will be continuously updated and optimized.

[0036] The microcontroller 1 converts the voltage and current signals input by the charging monitoring circuit 5 into digital quantities, then calculates the power and records it, analyzes the recorded charging power data to determine the trend of the charging power, and based on the analysis of the power trend, estimates the charging status, and then stops the power output after full charge.

[0037] The specific implementation is to take a power value once every sampling time as the current charging power value, and then subtract the previous power value from the current charging power value to get the power change, and put each power change and power value into the cache, and perform algorithm calculation after the data in the cache is full. The algorithm process is: 1. All power changes in the cache are less than the predetermined change value; 2. All power values ​​in the cache are accumulated to obtain the power average value, and the power average value is less than the predetermined average value; if both conditions are met, it is considered that charging is completed. If the conditions are not met, the new power change value and power value are replaced with the earliest power change data and power value in the cache, and then the above process is repeated until the conditions are met.

[0038] In some embodiments, the back-to-back series connection of the first MOS transistor Q1 and the second MOS transistor Q2 of the charging control execution circuit 3 is: (i) the drains D of the two MOS transistors are connected, and the two sources S are respectively connected to the output end of the power supply circuit and the input end of the charging interface circuit; or, (ii) the sources S of the two MOS transistors are connected, and the two drains D are respectively connected to the output end of the power supply circuit 2 and the input end of the charging interface circuit 4.

[0039] Taking the first MOS tube Q1 and the second MOS tube Q2 as P-polarity MOS tubes as an example, when charging the device, the control pin 11 of the microcontroller 1 connected to the gates of the first MOS tube Q1 and the second MOS tube Q2 outputs a low-level voltage, the first MOS tube Q1 and the second MOS tube Q2 are turned on, and the current can be output to the positive pin of the charging interface circuit 4 through the first MOS tube Q1 and the second MOS tube Q2; when the device is fully charged, the control pin 11 of the microcontroller 1 connected to the gates of the first MOS tube Q1 and the second MOS tube Q2 outputs a high-level voltage, the first MOS tube Q1 and the second MOS tube Q2 are turned off, and the current cannot be output to the positive pin of the charging interface circuit 4 through the first MOS tube Q1 and the second MOS tube Q2. The first MOS tube Q1 and the second MOS tube Q2 are turned on and off by the voltage signal given by the control pin 11 of the microcontroller 1, so as to realize the output of the power supply circuit 2 to the positive pin of the charging interface circuit 4. The use of two MOS transistors Q1 and Q2 can also overcome the characteristics of the body diode in the MOS tube, prevent the electronic device from backflowing power into the charger, and better protect the electronic device.

[0040] In some embodiments, the charger also includes a warning light circuit 7, which includes a third resistor R3 and an LED light 71, wherein the input end of the third resistor R3 is connected to the light control pin 15 of the microcontroller 1, the output end of the third resistor R3 is connected to one end of the LED light 71, and the other end of the LED light 71 is grounded.

[0041] In some embodiments, the specific circuit diagram of the power supply circuit 2 is as follows: Figure 3 As shown, this embodiment and Figure 3 In the power supply circuit, a flyback switching power supply is used. The AC mains electricity passes through the bridge stack composed of fuse FR1, diodes D1, D2, D3, and D4 to rectify the alternating current into a unidirectional DC current. The FR1 fuse has a protection function. When the subsequent circuit has an overcurrent short circuit, the current will be cut off. L is connected to the fuse FR1 and connected in series to the positive end of D1 and the negative end of D2. N is connected to the positive end of D3 and the negative end of D4. The negative end of D1 and the negative end of D3 are the positive poles of the DC voltage, and the positive ends of D3 and D4 are the negative poles of the DC voltage, which is the primary ground VSS of the power supply. The rectified DC voltage is a steamed bun wave and cannot be used directly by the circuit. C12, L1, and C13 filter the rectified steamed bun wave into a smooth and stable DC voltage. L1 is connected between the positive poles of C12 and C13 to form a π-type LC filter.

[0042] U3 is a power controller. In this embodiment, an IC with a built-in PWM controller, a high-voltage MOS tube and a current sampling is selected for power control. Pins 5, 6, 7 and 8 of U3 are connected to pin 4 of transformer T1, pin 1 is connected to the primary ground VSS of the power supply, pin 2 is the chip power supply pin connected to the positive pole of C17, pin 3 is the loop feedback connected to pin 4 of U4 and pin 1 of C19, and pin 4 is the detection and protection pin connected to one end of R15 and R16. R10, R11, C14 and D5 form a peak absorption network for protecting power MOS and absorbing noise. R10 is connected in parallel with C14, one end is connected to VH and the other end is connected to R11. The other end of R11 is connected to the negative end of D5, and the positive end of D5 is connected to pin 4 of T1. R13, D6, C17 are the primary power supply rectifier circuit, one end of R13 is connected to the 5th pin of T1, and the other end is connected to the positive end of D6, the positive end of C17 is connected to the negative end of D6, and the negative end is connected to VSS, C19 is the filter capacitor in the feedback loop, one end is connected to the 3rd pin of U3, and the other end is connected to VSS, one end of R15 is connected to the 5th pin of T1, and the other end is connected to the 4th pin of U4 and one end of R6, and the other end of R6 is connected to VSS. T1 is the transformer in the power supply circuit, pins 1 and 4 are the main coils of the switching transformer, pins 5 and 6 are the primary auxiliary coils, which provide working voltage and detection for the primary chip, and pins 9 and 10 are the secondary coils.

[0043] U4 is an isolation optocoupler, isolating the primary and secondary transmission voltage signals in the power supply voltage regulation loop. C18 is a Y capacitor, connected across the power supply primary ground VSS and the power supply secondary ground GND. In this example, synchronous rectification is used for secondary rectification, and other rectification methods such as diodes can also be used. U2 is a secondary synchronous rectification IC. Pins 5, 6, 7, and 8 of U2 are connected to pin 9 of T1 and R14, and pins 1 and 2 are connected to the power supply secondary ground GND. Pin 4 is the power pin of the synchronous rectification IC. C15 and R12 are externally connected. The other end of C15 is connected to GND, and the other end of R12 is connected to pin 10 of T1, i.e. VCC. R14 and C16 are connected in series, and the other end of C16 is connected to GND, forming an absorption circuit to protect U2.

[0044] In one embodiment, the specific circuit diagram is as follows Figure 4 As shown, Figure 4 U1 is a microcontroller with functions such as charging management, power management, and data acquisition. The full power-off algorithm is executed in this chip. Pin 1 is connected to the RT1 temperature sensor for over-temperature protection. Pin 4 is connected to the C4 capacitor filter. Pins 5, 6, 7, and 8 are data pins, which can perform data transmission and protocol interaction with the device during charging. Pins 9 and 10 are current acquisition signal input pins, which are converted into current digital quantities inside U1. Pins 11, 12, 19, and 20 are power control loop pins. Pins 11 and 12 are connected to pin 19 through the C5, C6, C7, C8, R6, and R7 resistor-capacitor network. Pin 19 is connected to pin 1 of the optocoupler U4. Pin 13 is the LED status drive pin. Pin 16 is the voltage acquisition signal input pin, which is converted into voltage digital signal quantities inside U1. Pin 17 is the control pin of the charging control execution circuit, and pin 21 is connected to GND.

[0045] The first MOS tube Q1 and the second MOS tube Q2 form a back-to-back series MOS tube switch circuit. This design can prevent the current of the external device from flowing back to the charger through the body diode in the MOS. In this example, the source S of the two MOS is connected to the drain D output, and the drain D can also be connected to the source S output. The gate G of the two MOS is connected to the U1 microcontroller. In the charging state, the 17th pin of U1 outputs a high level, Q1 and Q2 are turned on, and the current can be provided to the device from VCC through Q1 and Q2 to VBUS. In the full state or the state where the device is not inserted, it can be defined according to the actual design that the 17th pin of U1 outputs a low level, Q1 and Q2 are turned off, and the current cannot flow from VCC to VBUS, thereby disconnecting the charging of the device.

[0046] The first resistor R1 and the second resistor R2 are connected in series between VBUS and GND. Their connection point is the voltage divider of the VBUS voltage, which is connected to pin 16 of U1 for voltage data sampling. RS1 is a current sensing resistor, which is a high-precision, low-resistance resistor. When current flows through the sampling resistor RS1, a voltage difference is generated at its two ends. After filtering by R9 and C9, the differential input is input to pins 9 and 10 of U1 for current data sampling.

[0047] LED1 and R3 are the warning light circuit. LED1 and R3 are connected in series to the 13th pin of U1 and GND. When U1 and the 13th pin output high level, LED1 lights up. When U1 and the 13th pin output low level, LED turns off. USB1 is the charging interface. In this example, it is a USB-TYPEC interface. This interface can also be a USB TYPEA or other DC port.

[0048] The specific embodiments in the present invention are merely explanations of the present invention, and are not limitations of the present invention. After reading this specification, those skilled in the art may make modifications to the embodiments without any creative contribution as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A charger, characterized in that: It comprises a microcontroller (1), and a power supply circuit (2), a charging control execution circuit (3), a charging interface circuit (4), and a charging monitoring circuit (5) respectively connected to the microcontroller; The charging control execution circuit is a first MOS tube Q1 and a second MOS tube Q2 connected in series back to back, the gates G of the two MOS tubes are connected to the control pin (11) of the microcontroller, one end of the charging control execution circuit is connected to the power supply circuit, and the other end is connected to the charging interface circuit; The charging monitoring circuit is connected in parallel with the charging interface circuit, and comprises a first resistor R1, a second resistor R2 and a sampling resistor RS1 connected in series, wherein the input end of the first resistor R1 is connected to one end pin of the charging interface circuit, the output end of the first resistor R1 is connected to a first sampling pin (12) of a microcontroller and the input end of the second resistor R2; the output end of the second resistor R2 is connected to a second sampling pin (13) of the microcontroller and is grounded; the output end of the sampling resistor RS1 is connected to a third sampling pin (14) of the microcontroller and the other end pin of the charging interface circuit; A charging and disconnecting processing module (6) is also provided on the microcontroller.

2. The charger according to claim 1, characterized in that: The back-to-back series connection of the first MOS transistor Q1 and the second MOS transistor Q2 of the charging control execution circuit is as follows: (i) the drains D of the two MOS transistors are connected, and the two sources S are respectively connected to the output end of the power circuit and the input end of the charging interface circuit; or, (ii) the sources S of the two MOS transistors are connected, and the two drains D are respectively connected to the output end of the power circuit and the input end of the charging interface circuit.

3. The charger according to claim 1, characterized in that: It also includes a warning light circuit (7), which includes a third resistor R3 and an LED light (71), wherein the input end of the third resistor R3 is connected to a light control pin (15) of the microcontroller, the output end of the third resistor R3 is connected to one end of the LED light, and the other end of the LED light is grounded.

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