An electronic device compatible with charging

Abstract

The utility model discloses a kind of compatible charging electronic equipment, including a circuit board, overvoltage protection circuit, charging circuit and compatible circuit are equipped on the circuit board;The compatible circuit connects overvoltage protection circuit and charging circuit;The overvoltage protection circuit exports power supply voltage after overvoltage protection to the input voltage inputted from outside, compatible circuit is switched automatically between the output charging voltage after voltage reduction and output charging voltage according to the voltage of power supply voltage, and carries out anti-backflow protection;Charging circuit charges according to charging voltage.By control module voltage automatic identification and switch to corresponding module, select voltage reduction or directly output 5V charging voltage, different input voltage charging function can be realized, the problem that existing charging circuit cannot be compatible with different input voltage simultaneously is solved.

Description

Technical Field

[0001] This utility model relates to the field of electronic technology, and in particular to a rechargeable electronic device. Background Technology

[0002] Currently, chargers or adapters for electronic devices typically provide charging voltages of 5V and 9V. Because the internal charging circuitry of electronic devices is fixed and the charging chip has limited voltage tolerance, the charging voltage pins can only support 5V charging, limiting the use of only one type of adapter. When switching to a different adapter, the existing charging circuitry will not function properly, thus preventing the device from charging and resulting in poor charging compatibility.

[0003] For example, in electronic devices that support 5V adapters, since the 5V adapter can directly provide a 5V input voltage, the charging circuit only needs to include an overvoltage protection chip and a charging chip. The 5V input voltage, after passing through the overvoltage protection, outputs a 5V charging voltage for the charging chip. If a 9V adapter is inserted externally, the overvoltage protection chip does not have a voltage reduction function; it can only protect against abnormally high voltages. The 9V input voltage, after passing through the overvoltage protection chip, will still output 9V, which will damage the charging chip.

[0004] In electronic devices that support 9V adapters, the 9V adapter directly provides a 9V input voltage. The charging circuit includes an overvoltage protection chip, a 9V to 5V step-down chip, and a charging chip. After overvoltage protection, the 9V input voltage still outputs 9V, which is then stepped down to 5V by the 9V to 5V step-down chip for use by the charging chip. If a 5V adapter is plugged in, the 5V input voltage prevents the 9V to 5V step-down chip from functioning properly, thus preventing it from outputting the charging voltage and causing the charging chip to malfunction, resulting in no charging.

[0005] Therefore, existing charging circuits can only use one type of adapter with a fixed specification and cannot be compatible with two charging specifications simultaneously. Consequently, the existing technology needs further improvement and enhancement. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a compatible charging electronic device to solve the problem that existing charging circuits cannot be compatible with different input voltages at the same time.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A rechargeable electronic device includes a circuit board with an overvoltage protection circuit and a charging circuit, wherein the circuit board also has a compatibility circuit; the compatibility circuit is connected to the overvoltage protection circuit and the charging circuit.

[0009] The overvoltage protection circuit provides overvoltage protection for the external input voltage and then outputs a power supply voltage. The compatibility circuit automatically switches between the output charging voltage and the output charging voltage after voltage reduction based on the power supply voltage value, and provides backflow protection. The charging circuit charges according to the charging voltage.

[0010] In the aforementioned compatible charging electronic device, the compatible circuit includes a control module, a step-down module, a load switch module, and an anti-backflow module; the control module is connected to the step-down module, the load switch module, and the overvoltage protection circuit; the anti-backflow module is connected to the step-down module, the load switch module, and the charging circuit.

[0011] The control module switches between the step-down module and the load switch module based on the power supply voltage. When the step-down module is working, it steps down the power supply voltage and outputs a charging voltage to the anti-backflow module. When the load switch module is working, it outputs a charging voltage to the anti-backflow module based on the power supply voltage. The anti-backflow module outputs the charging voltage to the charging circuit and also prevents the charging voltage from flowing back.

[0012] In the aforementioned compatible charging electronic device, the control module includes a first switching transistor, a second switching transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor;

[0013] The gate of the first switching transistor is connected to one end of the first resistor and one end of the second resistor. The other end of the first resistor is connected to the output terminal of the overvoltage protection circuit and the load switch module. The other end of the second resistor and the drain of the first switching transistor are both grounded. The source of the first switching transistor is connected to one end of the third resistor, one end of the fourth resistor, the gate of the second switching transistor, and the buck module. The other end of the third resistor and the source of the second switching transistor are both grounded. The other end of the fourth resistor is connected to the power supply terminal. The drain of the second switching transistor is connected to one end of the fifth resistor, one end of the sixth resistor, and the load switch module. The other end of the fifth resistor is grounded. The other end of the sixth resistor is connected to the power supply terminal.

[0014] In the aforementioned compatible charging electronic device, the step-down module includes a step-down chip, the IN pin of the step-down chip is connected to the other end of the first resistor, the EN pin of the step-down chip is connected to the source of the first switching transistor, and the OUT pin of the step-down chip is connected to the anti-backflow module.

[0015] In the aforementioned compatible charging electronic device, the load switch module includes a switch chip, the IN pin of the switch chip is connected to the other end of the first resistor, the EN pin of the switch chip is connected to the drain of the second switch transistor, and the OUT pin of the switch chip is connected to the anti-backflow module.

[0016] In the aforementioned compatible charging electronic device, the anti-backflow module includes a third switch and a fourth switch. The gate of the third switch is connected to the OUT pin of the step-down chip and the drain of the fourth switch. The drain of the third switch is connected to the OUT pin of the switch chip and the drain of the fourth switch. The source of the third switch is connected to the source of the fourth switch and the input terminal of the charging circuit.

[0017] In the aforementioned compatible charging electronic device, the first switching transistor is a PMOS transistor, and the second switching transistor is an NMOS transistor.

[0018] In the aforementioned compatible charging electronic device, both the third and fourth switching transistors are PMOS transistors.

[0019] Compared to existing technologies, the compatible charging electronic device provided by this utility model includes a circuit board with an overvoltage protection circuit, a charging circuit, and a compatibility circuit. The compatibility circuit connects the overvoltage protection circuit and the charging circuit. The overvoltage protection circuit outputs a power supply voltage after providing overvoltage protection to the externally input voltage. The compatibility circuit automatically switches between a stepped-down charging voltage and a standard charging voltage output based on the power supply voltage value, and provides reverse current protection. The charging circuit charges according to the charging voltage. By automatically identifying the voltage value of the control module and switching to the corresponding module, selecting either a stepped-down or direct 5V charging voltage output, charging functions with different input voltages can be achieved, solving the problem that existing charging circuits cannot simultaneously support different input voltages. Attached Figure Description

[0020] Figure 1 This is a structural block diagram of the rechargeable electronic device provided by this utility model.

[0021] Figure 2 This is a circuit diagram of the compatible circuit provided by this utility model. Detailed Implementation

[0022] This utility model provides a rechargeable electronic device. To make the objectives, technical solutions, and advantages of this utility model clearer and more explicit, the following detailed description, with reference to the accompanying drawings and embodiments, further illustrates the utility model. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this utility model.

[0023] Please see Figure 1The compatible charging electronic device provided by this utility model includes a circuit board on which a conventional overvoltage protection circuit 10, a charging circuit 20, and an improved compatible circuit 30 are provided. The compatible circuit 30 connects the overvoltage protection circuit 10 and the charging circuit 20. The overvoltage protection circuit 10 provides overvoltage protection to the externally input voltage VBUS_IN and then outputs a power supply voltage VBUS. The compatible circuit 30 automatically switches between a stepped-down charging voltage and an output charging voltage based on the value of the power supply voltage VBUS, and provides reverse current protection. The charging circuit 20 charges according to the charging voltage.

[0024] It should be understood that any electronic device with charging functionality can have the compatibility circuit 30 added to achieve compatibility with different charging specifications. When the adapter or charger is connected to the electronic device, a USB interface or power interface can be used, as long as it can provide an input voltage of 5V or 9V VBUS_IN. This embodiment mainly focuses on the compatibility processing of the input voltage VBUS_IN and does not limit the specific input interface type. The overvoltage protection circuit 10 preferably consists of an overvoltage protection chip of model WP3116A-BPB2R and its peripheral components. When the input voltage VBUS_IN exceeds the upper limit (e.g., 11V), it disconnects (cuts off the internal path, thus protecting the downstream circuit from damage) to provide overvoltage protection. The charging circuit 20 preferably consists of a charging chip of model SC89890H and its peripheral components. Here, it mainly connects to its existing pins. The corresponding chip model and circuit structure are determined by the specific type of electronic device.

[0025] In this embodiment, the compatibility circuit 30 includes a control module 31, a step-down module 32, a load switch module 33, and an anti-backflow module 34. The control module 31 is connected to the step-down module 32, the load switch module 33, and the overvoltage protection circuit 10. The anti-backflow module 34 is connected to the step-down module 32, the load switch module 33, and the charging circuit 20. The control module 31 switches between the step-down module 32 and the load switch module 33 according to the power supply voltage VBUS. When the step-down module 32 is working, it steps down the power supply voltage VBUS and outputs a charging voltage to the anti-backflow module 34. When the load switch module 33 is working, it outputs a charging voltage to the anti-backflow module 34 according to the power supply voltage VBUS. The anti-backflow module 34 outputs the charging voltage to the charging circuit 20 for charging and also prevents the charging voltage from flowing back.

[0026] In this embodiment, when the control module 31 detects that the power supply voltage VBUS is a first voltage (e.g., 9V), it identifies that the currently inserted step-down module 32 is working and the load switch module 33 is not working; when the detected voltage is a second voltage (e.g., 5V), it controls the step-down module 32 to not work and the load switch module 33 to work. The voltage values ​​are related to the type of the externally inserted charger or adapter (equivalent to the charging specification). The voltage value identification is the type determination process. In specific implementations, it can be replaced with a charging specification corresponding to other voltage values. In this way, regardless of whether the electronic device is connected to a 9V or 5V adapter, the control module 31 automatically identifies and switches to the corresponding module by the voltage value, selecting either step-down or direct output of the 5V charging voltage to achieve the charging function without burning out the components on the circuit board.

[0027] Please refer to the following: Figure 2 The control module 31 includes a first switch Q1, a second switch Q2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The gate G of the first switch Q1 is connected to one end of the first resistor R1 and one end of the second resistor R2. The other end of the first resistor R1 is connected to the output terminal of the overvoltage protection circuit 10 and the load switch module 33. The other end of the second resistor R2 and the drain D of the first switch Q1 are both grounded. The source S of the first switch Q1 is connected to one end of the third resistor R3, one end of the fourth resistor R4, the gate of the second switch Q2, and the buck module 32. The other end of the third resistor R3 and the source of the second switch Q2 are both grounded. The other end of the fourth resistor R4 is connected to the power supply terminal (providing a power supply voltage of 3.3V). The drain of the second switch Q2 is connected to one end of the fifth resistor R5, one end of the sixth resistor R6, and the load switch module 33. The other end of the fifth resistor R5 is grounded, and the other end of the sixth resistor R6 is connected to the power supply terminal.

[0028] The first switch Q1 is preferably a PMOS transistor. The voltage on the gate of Q1 is obtained by dividing the power supply voltage VBUS using the first resistor R1 and the second resistor R2, which corresponds to the turn-on voltage V. GS Q1 is turned on when the on-state voltage is low, and turned off when the on-state voltage is high. The second switch Q2 is preferably an NMOS transistor, which is turned on when the voltage on its gate is high and turned off when the voltage on its gate is low. When Q1 is off, the voltage division of the 3.3V supply voltage by the third resistor R3 and the fourth resistor R4 is the gate voltage of Q2 and the enable voltage of the buck module 32; when Q1 is on, it directly pulls this voltage division low. When Q2 is off, the voltage division of the 3.3V supply voltage by the fifth resistor R5 and the sixth resistor R6 is the enable voltage of the load switch module 33; when Q2 is on, it directly pulls the enable voltage of the load switch module 33 low.

[0029] In this embodiment, the step-down module 32 includes a step-down chip U1. The IN pin of the step-down chip U1 is connected to the other end of the first resistor R1, the EN pin of the step-down chip U1 is connected to the source S of the first switching transistor Q1, and the OUT pin of the step-down chip U1 is connected to the anti-backflow module 34.

[0030] The preferred model of the step-down chip U1 is SY81105ADT. It operates when the voltage on its EN pin is high and not when it is low. When operating, the step-down chip U1 reduces the 9V voltage on its IN pin to 5V, which is then output from its OUT pin. It should be understood that the step-down chip U1 has other pins and peripheral components; this description mainly focuses on the improved connection relationships, and the existing connections are not detailed. If the voltage on the IN pin of U1 is not 9V, it will not operate.

[0031] The load switch module 33 includes a switch chip U2. The IN pin of the switch chip U2 is connected to the other end of the first resistor R1, the EN pin of the switch chip U2 is connected to the drain D of the second switch Q2, and the OUT pin of the switch chip U2 is connected to the anti-backflow module 34.

[0032] The preferred model of the switch chip U2 is ETA6042D2G. When the voltage on its EN pin is high, the internal path is open, and its IN pin is connected to the OUT pin, so the voltage on the IN pin can be output from the OUT pin. Conversely, when the EN pin is low, the internal path is closed, the connection between the N pin and the OUT pin is broken, and there is no output from the OUT pin. It should be understood that the switch chip U2 also has some other pins and peripheral devices. This description mainly focuses on the improved connection relationship, and the existing connection is not detailed.

[0033] In this embodiment, when the charger or adapter's charging specification is 5V, the step-down chip U1 is automatically deactivated, and the switching chip U2 is activated; when the charging specification is 9V, the step-down chip U1 is automatically activated, and the switching chip U2 is deactivated. Therefore, the resistance values ​​of R1 to R6 need to be set based on the conduction characteristics of Q1 and Q2, and the threshold voltages of the step-down chip U1 and the switching chip U2. Specifically:

[0034] When a 5V charger or adapter is plugged in, control Q1 is turned on, thereby pulling down the voltage on the EN pin of buck chip U1, so buck chip U1 will not work, resulting in the following formula 1:

[0035] 5×R2 / (R1+R2)<3.3-1.1=2.2 Formula 1;

[0036] When a 9V charger or adapter is plugged in, control Q1 is cut off, pulling the voltage on the EN pin of step-down chip U1 high (the specific voltage value is controlled by the voltage divider of R3 and R4). Step-down chip U1 then steps down the 9V power supply voltage VBUS to 5V and outputs it, resulting in the following formula 2:

[0037] 9×R2 / (R1+R2)>3.3-0.3=3 Formula 2;

[0038] Where 3.3 is the supply voltage, 1.1 is the maximum value of the conduction voltage of Q1, and 0.3 is the minimum value of the conduction voltage of Q1.

[0039] Solving the equations simultaneously using formulas 1 and 2, we get...

[0040] If 0.5×R1<R2<0.785×R1, then the preferred resistance value of the first resistor R1 is 10KΩ and the resistance value of the second resistor R2 is 6.8KΩ.

[0041] To ensure that the buck converter U1 operates when a 9V charger or adapter is plugged in, it is crucial to ensure that the voltage at the EN pin of U1, after the 3.3V supply voltage is divided by resistors R3 and R4, is greater than its threshold voltage (1.32V). Preferably, both the third resistor R3 and the fourth resistor R4 have a resistance of 100KΩ. This ensures that when Q1 is off, the voltage at the EN pin of U1 after voltage division is 3.3 / 2 = 1.65V, which is greater than U1's threshold voltage, thus enabling the buck converter U1 to operate.

[0042] To ensure that switch chip U2 operates when a 5V charger or adapter is plugged in, it is crucial to guarantee that the voltage at the EN pin of switch chip U2, after the 3.3V supply voltage is divided by resistors R5 and R6, is greater than its threshold voltage (2.16V). Preferably, the fifth resistor R5 has a resistance of 100KΩ and the sixth resistor R6 has a resistance of 510KΩ. This ensures that when Q2 is off, the voltage at the EN pin of U2 after voltage division is 3.3 / 2 = 2.75V, which is greater than U2's threshold voltage.

[0043] Since the second switch Q2 is an NMOS transistor with a conduction voltage range of 0.35V to 1.1V, when Q1 is off (input is 9V), the voltage division of R3 and R4 is 1.65V, which can ensure that Q2 is turned on, thereby pulling the EN pin of the switch chip U2 low, ensuring that the switch chip U2 does not work when the input is 9V.

[0044] Please continue reading. Figure 2The anti-backflow module 34 includes a third switch Q3 and a fourth switch Q4. The gate of the third switch Q3 is connected to the OUT pin of the step-down chip U1 and the drain of the fourth switch Q4. The drain of the third switch Q3 is connected to the OUT pin of the switch chip U2 and the drain of the fourth switch Q4. The source of the third switch Q3 is connected to the source of the fourth switch Q4 and the input terminal of the charging circuit 20 (specifically, the VBUS (5V) pin of the charging chip).

[0045] In this circuit, both the third switch Q3 and the fourth switch Q4 are PMOS transistors, requiring the selection of transistors capable of handling high currents, preferably PMOS transistors with a maximum current of 16A. In practical implementation, high-power unidirectional diodes can be used to replace Q3 and Q4. For example, the anode of one diode can be connected to the OUT pin of the step-down chip U1, the anode of another diode can be connected to the OUT pin of the switching chip U2, and the cathode of one diode can be connected to the cathode of the other diode and the input terminal of the charging circuit 20.

[0046] When the buck chip U1 outputs 5V and the switching chip U2 has no output, the gate of Q3 is high-level cutoff and the gate of Q4 is low-level conduction. The 5V voltage output by the buck chip U1 is supplied to the charging circuit 20 through Q4. At this time, Q3 is cut off, and the 5V voltage will not flow back to the switching chip U2.

[0047] When the buck chip U1 has no output and the switching chip U2 outputs 5V, the gate of Q3 is low and conducting, and the gate of Q4 is high and cutting off. The 5V voltage output by the switching chip U2 is supplied to the charging circuit 20 through Q3. At this time, Q4 is cut off, and the 5V voltage will not flow back to the buck chip U1.

[0048] Please continue reading. Figure 1 and Figure 2 The working principle of the electronic device is as follows:

[0049] When the input voltage VBUS_IN is 5V, the output power supply voltage VBUS after passing through the overvoltage protection circuit 10 is also 5V. Through the voltage divider of R1 and R2, the gate of Q1 is at a low level. Q1 conducts, pulling the EN pin of the buck chip U1 low, so the buck chip U1 does not work, and its OUT pin is at a low level, causing Q3 to conduct. At the same time, the conduction of Q1 pulls the gate of Q2 low, so Q2 is cut off. The voltage divider of the 3.3V supply voltage by R5 and R6 pulls the EN pin of the switching chip U2 high. The switching chip U2 works, its internal path is open, and the power supply voltage VBUS input at its IN pin is output from its OUT pin, causing Q4 to be cut off. Combined with the conduction of Q3, the power supply voltage VBUS output from Q3 becomes the charging voltage to charge the charging circuit 20. Q4 is used to prevent the charging voltage from flowing back to the buck chip U1.

[0050] When the input voltage VBUS_IN is 9V, the output power supply voltage VBUS after passing through the overvoltage protection circuit 10 is also 9V. Through the voltage divider of R1 and R2, the gate of Q1 is at a high level, and Q1 is cut off. The voltage divider of the 3.3V supply voltage by R3 and R4 pulls up the EN pin of the buck chip U1 to a high level, and the buck chip U1 works, stepping down 9V to 5V and outputting it from its OUT pin, causing Q3 to be cut off. At the same time, the voltage divider of R3 and R4 pulls up the gate of Q2 to a high level, and Q2 conducts, pulling down the EN pin of the switching chip U2 to a low level. The switching chip U2 is not working, and its OUT pin outputs a low level, causing Q4 to conduct. Combined with the cutoff of Q3, the 5V power supply voltage VBUS is output from Q4 and becomes the charging voltage to charge the charging circuit 20. Q3 is used to prevent the charging voltage from flowing back into the switching chip U2.

[0051] In summary, the compatible charging electronic device provided by this utility model can detect the input voltage value and automatically select either voltage reduction processing or direct output based on the voltage value. This intelligently identifies the type of adapter or charger plugged in by the user. It uses a purely hardware circuit to automatically switch the voltage processing path without any software intervention, resulting in high reliability. It also improves the compatibility of low-voltage charging chips and automatic compatibility with different charging specifications. Furthermore, it effectively prevents power backflow, enhancing product safety. The board-level components do not require additional high-voltage charger devices, saving costs.

[0052] It should be understood that the application of this utility model is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A rechargeable electronic device, comprising a circuit board, wherein the circuit board is provided with an overvoltage protection circuit and a charging circuit, characterized in that, The circuit board is also equipped with a compatibility circuit; the compatibility circuit is connected to the overvoltage protection circuit and the charging circuit. The overvoltage protection circuit provides overvoltage protection for the external input voltage and then outputs a power supply voltage. The compatibility circuit automatically switches between the output charging voltage and the output charging voltage after voltage reduction based on the power supply voltage value, and provides backflow protection. The charging circuit charges according to the charging voltage.

2. The rechargeable electronic device according to claim 1, characterized in that, The compatible circuit includes a control module, a step-down module, a load switch module, and an anti-backflow module; the control module is connected to the step-down module, the load switch module, and the overvoltage protection circuit; the anti-backflow module is connected to the step-down module, the load switch module, and the charging circuit. The control module switches between the step-down module and the load switch module based on the power supply voltage. When the step-down module is working, it steps down the power supply voltage and outputs a charging voltage to the anti-backflow module. When the load switch module is working, it outputs a charging voltage to the anti-backflow module based on the power supply voltage. The anti-backflow module outputs the charging voltage to the charging circuit and also prevents the charging voltage from flowing back.

3. The rechargeable electronic device according to claim 2, characterized in that, The control module includes a first switching transistor, a second switching transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor; The gate of the first switching transistor is connected to one end of the first resistor and one end of the second resistor. The other end of the first resistor is connected to the output terminal of the overvoltage protection circuit and the load switch module. The other end of the second resistor and the drain of the first switching transistor are both grounded. The source of the first switching transistor is connected to one end of the third resistor, one end of the fourth resistor, the gate of the second switching transistor, and the buck module. The other end of the third resistor and the source of the second switching transistor are both grounded. The other end of the fourth resistor is connected to the power supply terminal. The drain of the second switching transistor is connected to one end of the fifth resistor, one end of the sixth resistor, and the load switch module. The other end of the fifth resistor is grounded, and the other end of the sixth resistor is connected to the power supply.

4. The rechargeable electronic device according to claim 3, characterized in that, The step-down module includes a step-down chip. The IN pin of the step-down chip is connected to the other end of the first resistor, the EN pin of the step-down chip is connected to the source of the first switching transistor, and the OUT pin of the step-down chip is connected to the anti-backflow module.

5. The rechargeable electronic device according to claim 4, characterized in that, The load switch module includes a switch chip. The IN pin of the switch chip is connected to the other end of the first resistor, the EN pin of the switch chip is connected to the drain of the second switch transistor, and the OUT pin of the switch chip is connected to the anti-backflow module.

6. The rechargeable electronic device according to claim 5, characterized in that, The backflow prevention module includes a third switch and a fourth switch. The gate of the third switch is connected to the OUT pin of the step-down chip and the drain of the fourth switch. The drain of the third switch is connected to the OUT pin of the switch chip and the drain of the fourth switch. The source of the third switch is connected to the source of the fourth switch and the input terminal of the charging circuit.

7. The rechargeable electronic device according to claim 3, characterized in that, The first switch is a PMOS transistor, and the second switch is an NMOS transistor.

8. The rechargeable electronic device according to claim 6, characterized in that, Both the third and fourth switching transistors are PMOS transistors.

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