Contact type charging circuit and charging equipment

Abstract

The invention relates to the technical field of electronics, and discloses a contact type charging circuit and charging equipment. According to the contact type charging circuit provided by the invention, the detection module and the voltage regulation and control module are additionally arranged in the charging circuit; the detection module is used for sending a first signal to the voltage regulation and control module when the charging current is larger than or equal to a first preset current threshold value which may trigger current limiting, so that the voltage regulation and control module boosts the output voltage of the charging circuit. In this way, current limiting can be effectively prevented from being triggered in the charging process, and the charging speed is increased.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and in particular to a contact charging circuit and charging device. Background Technology

[0002] Devices using contact charging methods, such as smartwatches and electric toothbrushes, are widely used in daily life. Currently, contact chargers are generally used for charging these devices. However, after prolonged use, the charging contacts in both the charger's base and the device itself can oxidize due to prolonged exposure to air, resulting in increased resistance and consequently affecting charging speed. Summary of the Invention

[0003] To address the aforementioned problems, this application provides a contact-type charging circuit and a charging device.

[0004] In a first aspect, this application provides a contact charging circuit, including a charging contact element and a detection module and a voltage regulation module connected to the charging contact element; wherein, the detection module is used to acquire a first circuit parameter of the contact charging circuit during the charging process, the first circuit parameter being positively correlated with the charging current of the contact charging circuit during the charging process; the detection module is also used to send a first signal to the voltage regulation module when the charging current is greater than or equal to a first preset current threshold; the voltage regulation module is used to increase the first charging voltage of the charging circuit during the charging process to a second charging voltage when it receives the first signal.

[0005] In this embodiment, when the output current of the charging circuit reaches a first preset current threshold that may trigger current limiting, the output voltage of the charging circuit is increased (e.g., from 5V to 10V). This increases the input voltage of the terminal device's switching circuit module, ensuring that the battery's charging requirements are met without triggering current limiting measures, thus improving charging speed.

[0006] In some embodiments, the first signal may be a high-level signal. The charging contact element may be the charging contact point mentioned in the embodiments of this application.

[0007] In one possible implementation of the first aspect, the first preset current threshold is determined based on the contact impedance between the contact charging circuit and the electronic device being charged during the charging process.

[0008] In one possible implementation of the first aspect, the detection module is further configured to send a second signal to the voltage regulation module when the charging current is less than a second preset current threshold; the voltage regulation module is configured to restore the second charging voltage of the contact charging circuit during the charging process to the first charging voltage when it receives the second signal; the second preset current threshold is less than the first preset current threshold.

[0009] In some embodiments, the second signal may be a low-level signal.

[0010] In some embodiments, the voltage regulation module can also restore the charging voltage output by the charging circuit when the output current of the charging circuit is less than or equal to a second preset current threshold. It can be understood that the second preset current threshold is a current value that will not trigger current limiting. When the output current of the charging circuit is less than or equal to the second preset current threshold, it is determined that current limiting measures will not be triggered, and therefore there is no need to boost the voltage. Thus, the charging voltage can be controlled to restore to the rated voltage.

[0011] In one possible implementation of the first aspect, the detection module includes a sampling resistor unit, a current detection unit, and a hysteresis circuit unit. The sampling resistor unit includes at least one sampling resistor connected in series. The current detection unit is used to obtain a first circuit parameter based on the total resistance of the at least one sampling resistor and the charging current of the charging circuit during the charging process, and to obtain a first voltage based on the first circuit parameter, wherein the first circuit parameter is the voltage across the sampling resistor unit. The hysteresis circuit unit is used to obtain a second voltage based on the first voltage, and to output a first signal to the voltage regulation module when the second voltage is greater than or equal to a first preset voltage threshold, and to output a second signal to the voltage regulation module when the second voltage is less than or equal to a second preset voltage threshold. The second preset voltage threshold is less than the first preset voltage threshold.

[0012] In one possible implementation of the first aspect, the voltage regulation module includes a boost circuit; the boost circuit is used to boost the first charging voltage of the contact charging circuit during the charging process to a second charging voltage when a first signal is received; the boost circuit is used to reduce the second charging voltage of the contact charging circuit during the charging process to the first charging voltage when a second signal is received.

[0013] In one possible implementation of the first aspect, the charging contact element includes a first charging contact element and a second charging contact element; the first end of the sampling resistor unit is connected to the first end of the boost circuit and the first input end of the current detection unit, respectively; the second end of the sampling resistor unit is connected to the first charging contact element and the second input end of the current detection unit, respectively; the output end of the current detection unit is connected to the first end of the hysteresis circuit unit; the second end of the hysteresis circuit unit is connected to the second end of the boost circuit and the power line; the second end of the boost circuit is connected to the power line; and the second charging contact element is connected to the grounding wire.

[0014] In one possible implementation of the first aspect, the hysteresis circuit unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, and a first comparator; the first terminal of the first resistor is used to receive a reference voltage, the second terminal of the first resistor is connected to the first terminal of the second resistor and the negative terminal of the first comparator, and the second terminal of the second resistor is grounded; the first terminal of the third resistor is connected to the output terminal of the current detection unit, the second terminal of the third resistor is connected to the positive terminal of the first comparator and the first terminal of the fourth resistor, and the second terminal of the fourth resistor is connected to the output terminal of the first comparator and the second terminal of the boost circuit.

[0015] In one possible implementation of the first aspect, after the first charging voltage is increased to the second charging voltage, the first charging current of the charging circuit during the charging process is reduced to the second charging current; the second preset current threshold is less than the second charging current.

[0016] In one possible implementation of the first aspect, the current sensing unit includes a current sensing amplifier, and the boost circuit includes a boost chip.

[0017] Secondly, this application provides a charging device, including the contact charging circuit mentioned in this application. Attached Figure Description

[0018] Figure 1 According to some embodiments of this application, a schematic diagram of a scenario in which a charger 200 charges a smartwatch 100 is shown;

[0019] Figure 2 A schematic diagram of a charging circuit is shown according to some embodiments of this application;

[0020] Figure 3 According to some embodiments of this application, a schematic diagram of a charging current trend curve is shown;

[0021] Figure 4 A schematic diagram of a charging circuit is shown according to some embodiments of this application;

[0022] Figure 5 A schematic diagram of a charging circuit is shown according to some embodiments of this application;

[0023] Figure 6 A schematic diagram of a charging circuit is shown according to some embodiments of this application;

[0024] Figure 7 A schematic diagram of a charging circuit is shown according to some embodiments of this application;

[0025] Figure 8According to some embodiments of this application, a schematic diagram of a charging current trend curve is shown. Detailed Implementation

[0026] The illustrative embodiments of this application include, but are not limited to, a contact charging circuit and a charging device.

[0027] It is understood that the charging devices mentioned in the embodiments of this application can be used for contact charging of terminal devices, such as smartwatches, electric toothbrushes, shavers, mobile phones, tablets and other terminal devices. This application does not limit them.

[0028] To better understand the solutions in the embodiments of this application, the following will first be combined with Figure 1 Taking the charging scenario of a smartwatch 100 as an example, the charging methods of terminal devices in some embodiments will be explained.

[0029] like Figure 1 As shown, the smartwatch 100 is charged using a contact charger 200, which includes a charging dock 201 and a power adapter (not shown). The charging dock 201 has charging contacts 210a and 210b, and the power adapter is connected to the charging dock 201. When the charging dock 201 needs to charge the smartwatch 100, the power adapter is connected to a power source, and the smartwatch 100 is placed on the charging dock 201. The charging contacts 210a and 210b of the charging dock 201 then make contact with the corresponding charging contacts (not shown) on the back of the smartwatch 100 to achieve charging.

[0030] It is understandable that charging contact points 210a and 210b, as well as the corresponding charging contact points on the back of the smartwatch 100, are all made of conductive materials, such as metal.

[0031] However, due to the potential oxidation of charging contacts 210a, 210b, and the smartwatch 100 over prolonged use, the impedance of these contacts increases during charging (e.g., fast charging, high battery rate charging). This increased impedance leads to a larger impedance voltage division at the charging contacts 210a, 210b, and the smartwatch 100. This increased impedance voltage reduces the voltage at the front end of the charging chip in the smartwatch, resulting in current limiting and a decrease in charging current, thus affecting the charging speed.

[0032] The following is combined Figure 2The charging principle is explained by showing the charging dock 201 and the circuit during the charging of the smartwatch 100.

[0033] like Figure 2 As shown, the charging dock 201 includes charging contact 210a and charging contact 210b, wherein charging contact 210a is connected to the voltage current converter (VCC) line, and charging contact 210b is connected to the ground (GND) line. The smartwatch 100 includes charging contact 110a, charging contact 110b, charging chip 110, and battery 130, wherein the charging chip 110 includes a switching circuit module 111.

[0034] When the charging dock 201 needs to charge the smartwatch 100, the charging dock 201 can be connected to a power source, and the smartwatch 100 can be placed on the charging dock 201. At this time, one end of the charging contact 110a of the smartwatch 100 is connected to the charging contact 210a of the charging dock 201, and the other end is connected to the input terminal of the switching circuit module 111 in the charging chip 110. The output terminal of the switching circuit module 111 is connected to the positive terminal of the battery 130, the negative terminal of the battery 130 is connected to the charging contact 110b of the smartwatch 100, and the charging contact 110b of the smartwatch 100 is connected to the charging contact 210b of the charging dock 201 to realize the charging of the smartwatch 100.

[0035] Understandably, according to the battery charging principle, the battery's input voltage needs to be greater than or equal to the battery's rated voltage (e.g., 4.5V) to achieve charging. That is, the output voltage of the switching circuit module 111 needs to be greater than or equal to the rated voltage of the battery 130 to charge it. Since the switching circuit module 111 also has certain circuit losses, such as impedance division (e.g., 0.3V) caused by the impedance of its components, the input voltage of the switching circuit module 111 must be greater than or equal to the rated voltage of the battery 130 (e.g., 4.5V) plus the impedance division voltage (0.3V) of the corresponding switching circuit module 110 (e.g., 4.8V) to achieve charging of the smartwatch 100.

[0036] The following is combined Figure 2 The circuit diagram shown for charging the charging dock 201 and the smartwatch 100 explains the reason for the current limiting situation during charging.

[0037] It is understandable that charging contacts 210a, 210b, 110a, and 110b are made of metal. After prolonged use, due to prolonged exposure to air, partial oxidation may occur, resulting in relatively high impedance at charging contacts 210a, 210b, 110a, and 110b. Therefore, according to formula (1), the impedance voltage division at charging contacts 210a, 210b, 110a, and 110b will be relatively large.

[0038] U1=I1·R1 (1)

[0039] Wherein, U1 refers to the total voltage division of charging contact points 210a, 210b, 110a, and 110b, R1 refers to the total impedance of charging contact points 210a, 210b, 110a, and 110b, and I1 is the charging current.

[0040] Since charging contact points 210a, 210b, 110a, 110b and charging chip 110 are connected in series, and the total voltage U in the circuit is constant (which is the output voltage of charging base 201), it can be concluded from the voltage formula (2) in the series circuit that the voltage at the input terminal of charging chip 110 (i.e. the voltage at the input terminal of the switching circuit module) U2 will decrease as the total voltage U1 of charging contact points 210a, 210b, 110a and 110b increases.

[0041] U = U1 + U2 (2)

[0042] When the total voltage U1 of charging contacts 210a, 210b, 110a, and 110b exceeds a certain value, causing the voltage U2 at the input of the switching circuit module to be less than the battery's rated voltage (e.g., 4.5V) plus the impedance voltage (0.3V) of the switching circuit module 110 (e.g., 4.8V), the charging base 201 will be unable to charge the battery. In this case, the charging base 201 will reduce the output charging current to reduce the total voltage U1 of charging contacts 210a, 210b, 110a, and 110b, thereby increasing the voltage U2 at the input of the switching circuit module and continuing to charge the battery.

[0043] It is understandable that the battery charging rate is determined by the charging current; when the current decreases, the charging speed will slow down.

[0044] It should be noted that the current and voltage input to the charging dock 201 via the adapter are constant, for example, 2A and 5V. The output voltage of the charging dock 201 is the same as that of the adapter, and the charging current trend curve of the charging dock 201 is shown in the figure. Figure 3 As shown in the image. Figure 3 The horizontal axis of the charging current trend curve represents the charging time t, and the vertical axis represents the charging current I1.

[0045] like Figure 3 As shown in the charging current trend curve L1, the charging process is divided into the initial charging load stage and the charging stage. During the initial charging load stage, the charging current gradually increases to the rated current of the adapter (e.g., 2A). During the charging stage, the current gradually decreases as the battery capacity increases.

[0046] For example, if the impedances corresponding to charging contacts 210a, 210b, 110a, and 110b in the circuit are relatively large (e.g., reaching 0.2Ω), and combined with the fixed impedance of the wires in the circuit (e.g., 0.1Ω), resulting in a total impedance of 0.3Ω, then when the charging current rises to a certain value (e.g., 1A) during the initial charging load phase, the total impedance voltage division in the circuit will reach 0.3V. At this time, if the output voltage of the charging base 201 is 5V, the voltage at the input terminal of the switching circuit module 111 will be 4.7V, which is less than the aforementioned rated battery voltage (e.g., 4.5V) plus the impedance voltage division value corresponding to the switching circuit module 110 (e.g., 0.3V) (e.g., 4.8V). In this case, the charging base 201 cannot charge the battery 130, and the charging base 201 will implement current limiting measures. For example, if... Figure 3 As shown by curve L2, the charging base 201 reduces the charging current to 0.5A to decrease the voltage drop across the total impedance in the circuit (e.g., to 0.15V) and increase the voltage at the input of the switching circuit module 111 (e.g., to 4.85V), ensuring normal charging of the battery 130. Furthermore, the charging base 201 still controls the charging current to gradually decrease as the battery capacity increases. This significantly reduces the charging speed and extends the charging time.

[0047] In view of this, this application provides a contact charging circuit (or charging circuit) that can be used in contact charging devices. For example... Figure 4 As shown, the charging circuit 210 provided in this application can be used in... Figure 2The charging circuit of the charging dock 201 mentioned above includes a detection module (e.g., a current sensing amplifier) ​​211 and a voltage regulation module (e.g., a boost chip) 212. The detection module 211 determines whether the output current of the charging circuit 210 reaches (e.g., is greater than or equal to) a first preset current threshold that may trigger current limiting during charging. The voltage regulation module 212 increases the output voltage of the charging circuit 210 (e.g., from 5V to 10V) when the output current of the charging circuit 210 reaches the first preset current threshold that may trigger current limiting. This allows for a voltage increase at the input of the terminal device's switching circuit module (e.g., the switching circuit module 111 of the smartwatch 100), ensuring that the battery charging requirements are met, current limiting is not triggered, and charging speed is increased.

[0048] In some embodiments, the detection module is used to acquire first circuit parameters of the charging circuit during the charging process, the first circuit parameters being positively correlated with the charging current; the detection module is also used to send a first signal (e.g., a high-level signal) to the voltage regulation module when the charging current is greater than or equal to a first preset current threshold; the voltage regulation module is used to increase the first charging voltage (e.g., rated voltage) of the charging circuit during the charging process to a second charging voltage when the first signal is received.

[0049] The first preset current threshold can be determined based on the contact impedance between the charging circuit and the terminal device being charged during the charging process. For example, it can be determined based on the limit value of the total impedance (including charging contact impedance and wire impedance) in the charging circuit 210 when the charging device charges the terminal device. For example, when the terminal device is a smartwatch 100, if the maximum contact impedance between the charging contact point on the charging circuit 210 and the charging contact point in the smartwatch 100, obtained based on manual experiments, is 0.2Ω, and the maximum impedance of the wire in the charging circuit 210 is 0.05Ω, then the impedance limit value in the charging circuit 210 when the charging base 201 charges the terminal device is 0.25Ω. For example, in a charging base 201 with a rated output voltage of 5V, if the input voltage of the switching circuit module 111 of the charging chip 110 of the terminal device needs to be greater than or equal to 4.8V, then the impedance voltage division in the charging circuit 210 cannot be greater than 0.2V. Based on the impedance limit of 0.25Ω in the charging circuit 210, it can be concluded that current limiting may be triggered when the output charging current of the charging circuit 210 is greater than or equal to 0.8A (i.e., 0.2 / 0.25), and current limiting will not be triggered when the charging current is less than 0.8A. Therefore, the current that may trigger current limiting (i.e., 0.8A) is set as the first preset current threshold. Thus, when the charging current output by the charging circuit 210 is detected to reach 0.8A, the output voltage of the charging circuit 210 is increased, thereby increasing the voltage at the input terminal of the switching circuit module 111, which will not trigger current limiting and effectively improve the charging speed.

[0050] In some embodiments, the voltage regulation module 212 can also restore the charging voltage output by the charging circuit 210 (e.g., reduce it from 10V to 5V) when the output current of the charging circuit 210 is less than or equal to a second preset current threshold. It is understood that the second preset current threshold is a current value that will not trigger current limiting. When the output current of the charging circuit 210 is less than or equal to the second preset current threshold, it is determined that current limiting measures will not be triggered, and therefore no voltage boosting is required. Thus, the charging voltage can be controlled to recover to the rated voltage.

[0051] In some embodiments, the detection module can be used to send a second signal (e.g., a low-level signal) to the voltage regulation module when the charging current is less than or equal to a second preset current threshold; the voltage regulation module is used to restore the second charging voltage of the charging circuit during the charging process to the first charging voltage when it receives the second signal, that is, to control the boosted charging voltage to be restored to the rated voltage.

[0052] In summary, the charging circuit provided in the embodiments of this application can avoid charging current limiting and effectively improve charging speed.

[0053] It is understood that the charging circuit provided in this application embodiment can be applied to both fast charging devices and slow charging devices.

[0054] Figure 5 A schematic diagram of a charging circuit 210 according to an embodiment of this application is shown, as follows: Figure 5 As shown, the charging circuit 210 includes a detection module 211 and a voltage regulation module 212, a charging contact 210a (as an example of a first charging contact element), and a charging contact 210b (as an example of a second charging contact element). The detection module 211 may include a sampling resistor unit 2111, a current detection unit 2112, and a hysteresis circuit unit 2121. The voltage regulation module 212 may include a boost unit 2122 (or a boost circuit).

[0055] The first terminal of sampling resistor unit 2111 is connected to the first terminal of boost unit 2122 and the first input terminal of current detection unit 2112, respectively. The second terminal of sampling resistor unit 2111 is connected to charging contact 210a and the second input terminal of current detection unit 2112, respectively. The output terminal of current detection unit 2112 is connected to the first terminal of hysteresis circuit unit 2121. The second terminal of hysteresis circuit unit 2121 is connected to the second terminal of boost unit 2122. The second terminal of boost unit 2122 is connected to the power supply line.

[0056] The current detection unit 2112 can be used to output a first voltage to the hysteresis circuit unit 2121 based on the total resistance of the sampling resistor unit 2111 and the detected charging current in the charging circuit.

[0057] The hysteresis circuit unit 2121 can be used to obtain a second voltage based on a first voltage, and can be used to output a high-level signal to the boost unit 2122 when the second voltage is greater than or equal to a reference high voltage threshold (as an example of a first preset voltage threshold); and to output a low-level signal to the boost unit 2122 when the first voltage is less than or equal to a reference low voltage threshold (as an example of a second preset voltage threshold).

[0058] The boost unit 2122 can be used to boost the first charging voltage of the charging circuit to a second charging voltage during the charging process when a high-level signal is received. The boost unit 2122 can also be used to reduce the second charging voltage of the charging circuit to the first charging voltage during the charging process when a low-level signal is received.

[0059] In some embodiments, the sampling resistor unit 2111 may include one or more sampling resistors connected in series.

[0060] In some embodiments, the current detection unit 2112 may include a current detection amplifier.

[0061] In some embodiments, the boost unit 2122 may be a boost chip.

[0062] Figure 6 Taking the sampling resistor unit 2111 as the sampling resistor 2111a, the current detection unit 2112 as the current detection amplifier 2112a, and the boost unit 2122 as the boost chip as an example, a schematic diagram of a charging circuit of this application is shown.

[0063] like Figure 6 As shown, the first terminal of sampling resistor 2111a is connected to the first terminal of boost chip 2122a and the first input terminal of current sensing amplifier 2112a, respectively. The second terminal of sampling resistor 2111a is connected to charging contact 210a and the second input terminal of current sensing amplifier 2112a, respectively. The output terminal of current sensing amplifier 2112a is connected to the first terminal of hysteresis circuit unit 2121, the second terminal of hysteresis circuit unit 2121 is connected to the second terminal of boost chip 2122a, and the second terminal of boost chip 2122a is connected to the power supply line.

[0064] The current sensing amplifier 2112a can be used to output a first voltage to the hysteresis circuit unit 2121 based on the resistance value of the sampling resistor 2111a and the detected charging current in the charging circuit.

[0065] The hysteresis circuit unit 2121 can be used to obtain a second voltage based on a first voltage, and output a high-level signal to the boost chip 2122a when the second voltage is greater than or equal to a reference high-voltage threshold; and output a low-level signal to the boost chip 2122a when the first voltage is less than or equal to a reference low-voltage threshold. The boost chip 2122a is used to boost the first charging voltage of the charging circuit during the charging process to the second charging voltage when it receives a high-level signal. The boost chip 2122a is used to reduce the second charging voltage of the charging circuit during the charging process to the first charging voltage when it receives a low-level signal.

[0066] The following is combined Figure 7 The charging circuit shown describes the specific structure of the current detection amplifier 2112a and the hysteresis circuit unit 2121.

[0067] like Figure 7As shown, the current sensing amplifier 2112a includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a second comparator C2. The first terminal of the seventh resistor R7 is connected to the first terminal of the sampling resistor 2111a. The second terminal of the seventh resistor R7 is connected to the negative terminal of the second comparator C2 and the first terminal of the fifth resistor R5. The second terminal of the fifth resistor R5 is connected to the first terminal of the hysteresis circuit unit 2121 and the output terminal of the second comparator C2. The output terminal of the second comparator C2 is connected to the first terminal of the hysteresis circuit unit 2121. The first terminal of the eighth resistor R8 is connected to the second terminal of the sampling resistor 2111a. The second terminal of the eighth resistor R8 is connected to the first terminal of the sixth resistor R6 and the negative terminal of the second comparator C2. The second terminal of the sixth resistor R6 is connected to the reference voltage terminal and the ground terminal.

[0068] The first voltage V1 output by the current sensing amplifier 2112a can be determined based on the resistance value of the sampling resistor 2111a and the charging current in the charging circuit. In some embodiments, the voltage across the sampling resistor 2111a can be obtained based on the resistance value of the sampling resistor 2111a and the charging current in the charging circuit, and the first voltage V1 output by the current sensing amplifier 2112a can be obtained by amplifying the voltage across the sampling resistor 2111a by a preset factor.

[0069] In some embodiments, the first voltage V1 of the output of the current sense amplifier 2112a can be obtained based on the following formula:

[0070] V1 = (I1 * R1) * Gain

[0071] Where I1 is the charging current, R1 is the resistance of the sampling resistor 2111a, and Gain is the gain of the current sensing amplifier 2112a.

[0072] In some embodiments, the resistance values ​​of the fifth resistor R5 and the sixth resistor R6 can both be 1MΩ, and the resistance values ​​of the seventh resistor R7 and the eighth resistor R8 can both be 5KΩ, 2KΩ, 1KΩ, 20KΩ, 10KΩ, or 13.3KΩ, etc., then the corresponding voltage gains can be 200, 500, 1000, 50, 100, and 75, respectively. The resistance values ​​of the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8 can also be other values, and the corresponding voltage gains can also be other values. This application does not impose limitations.

[0073] like Figure 7As shown, the hysteresis circuit unit 2121 may include: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first comparator C1; wherein, the first terminal of the first resistor R1 is used to receive the reference voltage vin. The second terminal of the first resistor R1 is connected to the first terminal of the second resistor R2 and the negative terminal of the first comparator C1, and the second terminal of the second resistor R2 is grounded. The first terminal of the third resistor R3 is connected to the output terminal of the second comparator C2 of the current sensing amplifier 2112a, and the second terminal of the third resistor R3 is connected to the positive terminal of the first comparator C1 and the first terminal of the fourth resistor R4, and the second terminal of the fourth resistor R4 is connected to the output terminal of the comparator and the second terminal of the boost chip 2122a. The output terminal of the comparator is connected to the second terminal of the boost chip 2122a.

[0074] The hysteresis circuit unit 2121 can be used to obtain a second voltage based on a first voltage. When the second voltage is greater than or equal to a reference high voltage threshold, it outputs a high-level signal to the boost chip 2122a. When the first voltage is less than or equal to a reference low voltage threshold, it outputs a low-level signal to the boost chip 2122a.

[0075] The reference high-voltage threshold can be determined based on the following formula:

[0076]

[0077] Among them, V H As a reference high voltage threshold, V OH When the charging current I1 is the first preset current threshold, the output voltage of the current detection amplifier 2112a is V. R1 is the resistance of the first resistor R1, R2 is the resistance of the second resistor R2, R3 is the resistance of the third resistor R3, and R4 is the resistance of the fourth resistor R4. ref The reference voltage is input to the first terminal of the first resistor R1.

[0078] The reference low-pressure threshold can be determined based on the following formula:

[0079]

[0080] Among them, V L For reference low-voltage threshold, V OL When the charging current is the second preset current threshold, the output voltage of the current detection amplifier 2112a is V. R1 is the resistance of the first resistor R1, R2 is the resistance of the second resistor R2, R3 is the resistance of the third resistor R3, and R4 is the resistance of the fourth resistor R4. ref The reference voltage input to the first terminal of the first resistor R1, for example, is... Figure 7 The reference voltage vin is input to the first terminal of the first resistor R1.

[0081] In some embodiments, the second voltage can be obtained based on the following formula.

[0082]

[0083] Where V2 is the second voltage, V1 is the first voltage output of the current sensing amplifier 2112a, R1 is the resistance of the first resistor R1, R2 is the resistance of the second resistor R2, R3 is the resistance of the third resistor R3, R4 is the resistance of the fourth resistor R4, V ref The reference voltage is input to the first terminal of the first resistor R1.

[0084] Based on the above Figure 5-7 The circuit structure shown illustrates the charging process when the charging device mentioned in the embodiments of this application charges the electronic device being charged.

[0085] Figure 8 This diagram illustrates the charging current trend curve when a charging device charges an electronic device. Figure 8 The horizontal axis of the curve represents the charging time t, and the vertical axis represents the charging current I1.

[0086] like Figure 8 As shown in the charging current trend curve, the charging process is divided into the initial charging load stage and the charging stage. During the initial charging load stage, the charging voltage is the rated voltage of the charging device's adapter, for example, 5V. During the initial charging load stage, the charging current I1 gradually increases.

[0087] When the charging current I1 increases to 1A at time t1, which is greater than or equal to the first current threshold (e.g., 0.8A), the hysteresis circuit unit 2121 outputs a high-level signal to the boost chip 2122a, enabling the boost chip 2122a and raising the current charging voltage (5V) to a preset voltage value (e.g., 9V). At this time, the charging current no longer continues to draw loads but enters the charging stage, gradually decreasing as the battery capacity increases. When the charging current is 0.4A at time t2, which is less than or equal to the second current threshold (e.g., 0.5A), the hysteresis circuit unit 2121 outputs a low-level signal to the boost chip 2122a, turning off the boost chip 2122a and reducing the current charging voltage (9V) to the initial voltage (5V) for subsequent battery charging. It can be understood that when the charging voltage drops instantaneously, the charging current will have a small instantaneous increase, and then gradually decrease as the charging current increases. In some embodiments, when the charging voltage drops instantaneously, the boosted current (e.g., the current at time t3) can be less than the first preset current threshold. This can prevent the boost chip 2122a from being re-enabled, which would cause the charging voltage to rise again.

[0088] Understandable. Figure 8The diagram shown is merely a schematic representation of the current trend curve, and does not fully represent the actual charging curve. In some embodiments, the charging device may operate in a constant current mode, i.e., performing phased constant current charging at different levels. For example, if an electronic device starts charging at 10:00 and enters the charging load stage, the charging current I1 may be 0.25A during the period from 10:00 to 10:05; 0.4A during the period from 10:05 to 10:10; 0.55A during the period from 10:10 to 10:12; and 0.75A during the period from 10:12 to 10:14. At 10:15, when the charging current I1 is 1A, which is greater than or equal to the first current threshold (e.g., 0.8A), the hysteresis circuit unit 2121 outputs a high-level signal to the boost chip 2122a, enabling the boost chip 2122a and raising the current charging voltage (5V) to a preset voltage value (e.g., 9V). At this time, due to the limitation of charging power, the charging current no longer continues to draw load, but enters the charging stage, and the charging current momentarily drops to 0.75A. For example, the charging current is 0.75A during the period from 10:15 to 10:25. When the charging current decreases to 0.4A at 10:40, which is less than the second current threshold (e.g., 0.5A), the boost chip 2122a turns off, reducing the current charging voltage (9V) to the initial voltage (5V) for subsequent battery charging.

[0089] It is understandable that when the charging voltage of the charging circuit 220 drops instantaneously, the charging current I1 will experience a slight instantaneous increase. This increased charging current I1 can be less than or equal to the current corresponding to the first current level after the voltage boost, for example, the current corresponding to the first current level after the voltage boost is 0.75A. The boosted first current level could be 0.6A, etc. This prevents the boost chip 2122a from being re-enabled, which would cause the charging voltage to rise again.

[0090] It is understood that in some embodiments, the second preset current threshold may be less than the current value corresponding to the first current level after boosting (e.g., 0.75A as mentioned above).

[0091] In some embodiments, setting the second preset current threshold can be used to balance the input efficiency of the switching circuit module of the electronic device being charged. The switching circuit module is a buck charger. It is understood that when the charging voltage is relatively high, the ripple on the inductor in the switching circuit module will be large, increasing inductor losses and resulting in lower input efficiency of the switching circuit module under high voltage, for example, 85%-90%. Therefore, when the charging current is already relatively small, for example, less than the second preset threshold, the charging voltage can be reduced to improve the input efficiency of the switching circuit module.

[0092] It should be noted that the voltage boosting and bucking processes described above take a relatively short time. Therefore, the time taken for the voltage boosting and bucking processes was not calculated when describing the current corresponding to each time period in the examples above.

[0093] It should be noted that the charging current levels during the charging load phase and the charging phase can be preset according to actual needs, so that the charging current can be adjusted based on the preset levels during the actual charging process.

[0094] In summary, the charging circuit provided in the embodiments of this application can avoid charging current limiting and effectively improve charging speed.

[0095] In some embodiments, the charging circuit provided in this application may include a current detection unit and a controller. The current detection unit can be used to detect the charging current, and the controller can be used to increase the first charging voltage of the charging circuit to a second charging voltage during the charging process when the charging current is greater than or equal to a first preset current threshold. Furthermore, the controller can be used to restore the second charging voltage of the charging circuit to the first charging voltage during the charging process when the charging current is less than or equal to the first preset current threshold.

[0096] It is understood that the charging circuit provided in this application embodiment can be applied to both fast charging devices and slow charging devices.

[0097] In some embodiments, the voltage increase or decrease can also be controlled based on a software protocol. For example, additional communication contact structures can be added to the electronic device (e.g., a smartwatch) and the charging device to enable communication, thereby increasing the voltage based on the software protocol set in the electronic device (e.g., a smartwatch) and the charging device when the first preset current threshold is reached, in order to avoid current limiting and improve charging speed.

[0098] However, communication contacts are prone to poor contact, leading to communication interruptions or failures. The charging circuit provided in this embodiment, however, uses hardware such as a hysteresis circuit unit and a boost chip to regulate voltage, avoiding this problem and ensuring proper voltage regulation for 3C boost charging, thus guaranteeing charging quality. Furthermore, it eliminates the need for a dedicated communication protocol, making it compatible with any electronic device and highly adaptable. Additionally, it eliminates the need for dedicated communication contacts, requiring only charging contacts, thus saving on equipment costs.

[0099] Furthermore, the reference high voltage threshold and reference low voltage threshold of the hysteresis circuit unit in the charging circuit provided in this application can be set according to actual needs. For example, a wider hysteresis threshold can be set (i.e., the difference between the reference high voltage threshold and the reference low voltage threshold is increased), which can effectively prevent the charging socket output voltage and charging current from jumping back and forth, and improve the stability of charging.

[0100] This application provides a charging device including the charging circuit described above.

[0101] It should be noted that in the examples and description of this patent, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0102] Although this application has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made thereto without departing from the scope of this application.

Claims

1. A contact charging circuit, characterized in that, It includes a charging contact element and a detection module and a voltage regulation module connected to the charging contact element; wherein, The detection module is used to obtain the first circuit parameters of the contact charging circuit during the charging process, and the first circuit parameters are positively correlated with the charging current of the contact charging circuit during the charging process. The detection module is also used to send a first signal to the voltage regulation module when the charging current is greater than or equal to a first preset current threshold. The voltage regulation module is used to increase the first charging voltage of the charging circuit to a second charging voltage during the charging process when the first signal is received.

2. The contact charging circuit according to claim 1, characterized in that, The first preset current threshold is determined based on the contact impedance between the contact charging circuit and the electronic device being charged during the charging process.

3. The contact charging circuit according to claim 1 or 2, characterized in that, The detection module is also used to send a second signal to the voltage regulation module when the charging current is less than the second preset current threshold. The voltage regulation module is used to restore the second charging voltage of the contact charging circuit during the charging process to the first charging voltage when the second signal is received. The second preset current threshold is less than the first preset current threshold.

4. The contact charging circuit according to claim 3, characterized in that, The detection module includes a sampling resistor unit, a current detection unit, and a hysteresis circuit unit. The sampling resistor unit includes at least one sampling resistor, which are connected in series. The current detection unit is used to obtain the first circuit parameters based on the total resistance of the at least one sampling resistor and the charging current of the contact charging circuit during the charging process, and to obtain the first voltage based on the first circuit parameters, wherein the first circuit parameters are the voltage across the sampling resistor unit. The hysteresis circuit unit is used to obtain a second voltage based on the first voltage, and outputs the first signal to the voltage regulation module when the second voltage is greater than or equal to a first preset voltage threshold, and outputs the second signal to the voltage regulation module when the second voltage is less than or equal to a second preset voltage threshold; The second preset voltage threshold is less than the first preset voltage threshold.

5. The contact charging circuit according to claim 4, characterized in that, The voltage regulation module includes a boost circuit; The boost circuit is used to boost the first charging voltage of the contact charging circuit during the charging process to the second charging voltage when the first signal is received. The boost circuit is used to reduce the second charging voltage of the contact charging circuit during the charging process to the first charging voltage when the second signal is received.

6. The contact charging circuit according to claim 5, characterized in that, The charging contact element includes a first charging contact element and a second charging contact element; The first end of the sampling resistor unit is connected to the first end of the boost circuit and the first input end of the current detection unit, respectively; the second end of the sampling resistor unit is connected to the first charging contact element and the second input end of the current detection unit, respectively. The output terminal of the current detection unit is connected to the first terminal of the hysteresis circuit unit, the second terminal of the hysteresis circuit unit is connected to the second terminal of the boost circuit and the power line, and the second terminal of the boost circuit is connected to the power line. The second charging contact element is connected to the grounding wire.

7. The contact charging circuit according to claim 6, characterized in that, The hysteresis circuit unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, and a first comparator; The first terminal of the first resistor is used to receive a reference voltage, the second terminal of the first resistor is connected to the first terminal of the second resistor and the negative terminal of the first comparator, and the second terminal of the second resistor is grounded. The first end of the third resistor is connected to the output end of the current detection unit, the second end of the third resistor is connected to the positive terminal of the first comparator and the first end of the fourth resistor, and the second end of the fourth resistor is connected to the output end of the first comparator and the second end of the boost circuit.

8. The contact charging circuit according to claim 3, characterized in that, After the first charging voltage is increased to the second charging voltage, the first charging current of the charging circuit during the charging process is reduced to the second charging current; The second preset current threshold is less than the second charging current.

9. The contact charging circuit according to claim 5, characterized in that, The current detection unit includes a current detection amplifier, and the boost circuit includes a boost chip.

10. A charging device, characterized in that, Includes the contact charging circuit as described in any one of claims 1-9.

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