A charging circuit and chip

Abstract

The application provides a charging circuit and a chip, the charging circuit is provided with a charging current sampling end and a battery voltage sampling end, and the charging circuit comprises: a boosting module provided with a boosting switch and connected with an external power supply device; a linear regulation module provided with an adjusting tube and connected between an output node of the boosting module and an external battery; a comparison module receiving an input voltage, an input voltage of the boosting module, a first threshold voltage greater than the input voltage, and a second threshold voltage greater than the first threshold voltage; a first control module connected with an output end of the comparison module, the boosting switch and the charging current sampling end respectively, and the first control module is configured to control a switching state of the boosting switch when receiving a signal representing that the battery voltage is between the input voltage and the first threshold voltage, so that the charging current is in a trickle state. The circuit effectively reduces the invalid loss in the charging circuit and improves the charging efficiency of the external battery.

Description

Technical Field

[0001] This invention belongs to the field of integrated circuit technology, specifically relating to a charging circuit and chip. Background Technology

[0002] Currently, in the field of lithium battery charging, for applications where the input voltage is lower than the battery's full charge voltage, the input voltage is typically boosted before charging the battery. Using a switching boost circuit can achieve relatively high energy utilization efficiency and fast charging time. However, in existing technologies, during the trickle charging stage, a boost circuit first raises the output voltage to a fixed value, and then the charging circuit charges the battery with a small current, causing the battery voltage to gradually rise. During this stage, because the boosted voltage is a fixed value, the charging efficiency is relatively low when the battery voltage differs significantly from this fixed value. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a charging circuit and chip that improves the charging efficiency of external batteries.

[0004] This invention provides a charging circuit, which includes a charging current sampling terminal and a battery voltage sampling terminal. The charging circuit includes:

[0005] The boost module, equipped with a boost switch, is configured to connect to an external power supply.

[0006] A linear regulation module with an adjustment tube is connected between the output node of the boost module and the external battery. The current from the power supply device flows through the boost module and the linear regulation module to charge the external battery.

[0007] The comparison module has a first input terminal connected to the battery voltage sampling terminal, a second input terminal receiving the input voltage of the boost module, a third input terminal receiving a first threshold voltage greater than the input voltage, and a fourth input terminal receiving a second threshold voltage greater than the first threshold voltage.

[0008] The first control module is connected to the output terminal of the comparison module, the boost switch, and the charging current sampling terminal, respectively. The first control module is configured to control the switching state of the boost switch when it receives a signal representing the battery voltage between the input voltage and the first threshold voltage, so that the charging current is in a trickle state.

[0009] This invention also provides a charging chip, which includes the charging circuit provided in the above embodiments.

[0010] The charging circuit and chip provided by this invention control the boost switch to enable the boost module to enter the boost state. At this time, the voltage output by the boost module can be slightly greater than the battery voltage. The regulating transistor is in the normally on state without the need for the regulating transistor to change state, which effectively reduces the ineffective losses in the charging circuit and improves the charging efficiency of the external battery. Attached Figure Description

[0011] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0012] Figure 1 This is a schematic diagram of a charging circuit provided in an embodiment.

[0013] Figure 2 This is a schematic diagram of the various stages of the charging process.

[0014] Figure 3 A circuit diagram of a charging circuit provided for an embodiment.

[0015] Figure 4 This is a schematic diagram illustrating the charging modes at each stage of the charging process.

[0016] Figure 5 A schematic diagram of a charging circuit including a second control module is provided for an embodiment.

[0017] Figure 6 A schematic diagram of a charging circuit including a third control module is provided for an embodiment.

[0018] Figure 7 A schematic diagram of a charging circuit including a fourth control module is provided for an embodiment.

[0019] Figure 8 Another circuit diagram of the charging circuit provided for an embodiment. Detailed Implementation

[0020] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore merely examples and should not be used to limit the scope of protection of the present invention. It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0021] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0022] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0023] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0024] Example:

[0025] A charging circuit 1, see Figure 1 The charging circuit 1 is provided with a charging current sampling terminal 16 and a battery voltage sampling terminal 15. The charging circuit 1 includes:

[0026] The boost module 11, which is equipped with a boost switch 111, is configured to be connected to an external power supply device 2.

[0027] A linear adjustment module 12 with an adjustment tube 121 is connected between the output node of the boost module 11 and the external battery 3. The current from the power supply device 2 flows through the boost module 11 and the linear adjustment module 12 to charge the external battery 3.

[0028] The comparison module 13 has its first input terminal connected to the battery voltage sampling terminal 15, its second input terminal receiving the input voltage of the boost module 11, its third input terminal receiving a first threshold voltage greater than the input voltage, and its fourth input terminal receiving a second threshold voltage greater than the first threshold voltage.

[0029] The first control module 14 is connected to the output terminal of the comparison module 13, the boost switch 111, and the charging current sampling terminal 16, respectively. The first control module 14 is configured to control the switching state of the boost switch 111 when it receives a signal representing the battery voltage between the input voltage and the first threshold voltage, so that the charging current is in a trickle state.

[0030] It should be noted that the "external power supply device 2" described in this embodiment is "external" relative to the charging circuit 1, not "external" to the carrier on which the charging circuit 1 is located. Similarly, the "external battery 3" mentioned below is "external" relative to the charging circuit 1, and is not a limitation on the specific location of the "external battery 3". Similarly, the same applies to the external energy storage device, external peripheral circuit, and external electronic components mentioned below in this embodiment.

[0031] In this embodiment, the charging circuit 1 can be connected between the power supply device 2 and the external battery 3, converting the electrical energy output by the power supply device 2 into electrical energy that can be used to charge the external battery 3. The power supply device 2 may include, but is not limited to, an adapter, a USB port, a discharge device, etc. The external battery 3 may include a device capable of storing and releasing electrical energy; for example, the external battery 3 may include a lithium battery, a nickel-metal hydride battery, a nickel-cadmium battery, etc., and the type of external battery 3 is not specifically limited here. Furthermore, the external battery can also be considered a battery assembly containing one or more charging units. All charging units in the external battery 3 can be connected in series, parallel, or a combination of both, and output one positive terminal and one negative terminal. The structure of the external battery 3 is not specifically limited here.

[0032] It is important to note that since the operation of charging circuit 1 needs to be controlled based on charging current and battery voltage, charging circuit 1 necessarily includes a charging current sampling terminal 16 and a battery voltage sampling terminal 15. The charging current is obtained through the charging current sampling terminal 16, and the battery voltage is obtained through the battery voltage sampling terminal 15. The charging current sampling terminal 16 is configured to acquire a signal representing the charging current in charging circuit 1, and the battery voltage sampling terminal 15 is configured to acquire a signal representing the battery voltage in charging circuit 1. For example, when it is necessary to obtain the battery voltage, the battery voltage can be obtained by calculating the difference between the positive and negative terminal voltage values, or by connecting the negative terminal of the battery to ground and obtaining the positive terminal voltage value, or by acquiring a voltage that can be used to represent the battery voltage (e.g., a voltage that has a linear or functional relationship with the battery voltage). Here, no specific restrictions are placed on the method of obtaining the battery voltage, and similarly, no specific restrictions are placed on the setting point of the battery voltage sampling terminal 15. Similarly, no specific restrictions are placed on the setting point of the charging current sampling terminal 16.

[0033] In this embodiment, see Figure 2The charging process of external battery 3 typically involves three stages: trickle charging, constant current charging, and constant voltage charging. When the battery voltage is low, it enters trickle charging mode a, using a small charging current to gradually increase the battery voltage. When the battery voltage increases to exceed a certain threshold, it enters constant current charging mode b, ensuring a constant charging current and gradually increasing the battery voltage. When the battery is close to fully charged, it enters constant voltage charging mode c, using a constant voltage to keep the battery voltage essentially constant while the battery gradually decreases in voltage. This charging method balances charging safety and charging rate.

[0034] In this embodiment, the input voltage provided by the power supply device 2 can be boosted by the boost module 11 and adjusted by the linear adjustment module 12 before being supplied to the external battery 3 for charging. The comparison module 13 can receive the following four data: 1) battery voltage Vbat; 2) input voltage Vin of the boost module 11; 3) first threshold voltage Vth1; 4) second threshold voltage Vth2. The comparison module 13 can be configured to compare the above-collected data to obtain a comparison result. For example, the comparison module 13 can compare the battery voltage Vbat with the input voltage Vin, the first threshold voltage Vth1, and the second threshold voltage Vth2 respectively to obtain a comparison result of whether the battery voltage Vbat is greater than the input voltage Vin, the first threshold voltage Vth1, or the second threshold voltage Vth2. The comparison module 13 can be equipped with multiple logic devices to complete the set comparison logic. For example, the comparison module 13 can be equipped with a comparator. The first input terminal of the comparator receives the battery voltage Vbat, and the second input terminal receives the input voltage Vin. When the battery voltage Vbat is greater than the input voltage Vin, the comparator outputs a high level; otherwise, it outputs a low level. Similarly, the comparison circuit for battery voltage Vbat with the first threshold voltage Vth1 and the second threshold voltage Vth2 is similar.

[0035] It should be noted that the charging circuit 1 provided in this embodiment is suitable for situations where the input voltage Vin is less than the first threshold voltage Vth1. In this charging circuit 1, the second threshold voltage Vth2 is greater than the first threshold voltage Vth1. The specific values ​​of the first threshold voltage Vth1 and the second threshold voltage Vth2 can be determined according to actual needs. This charging circuit 1 includes, but is not limited to, Buck-Boost charging circuits, Sepic charging circuits, Cuk charging circuits, Zeta charging circuits, etc.

[0036] Furthermore, in some embodiments, see Figure 3The boost module 11 can be a common boost topology. For example, the boost module 11 can also include a first switch 113, an inductor 112, and a capacitor 114. The first end of the inductor 112 is connected to the power supply terminal, the second end of the inductor 112 is connected to the first end of the boost switch 111 and the first end of the first switch 113 respectively, the second end of the boost switch 111 is connected to the reference ground terminal, the second end of the first switch 113 is connected to the linear adjustment module 12 and the first end of the capacitor 114 respectively, and the second end of the capacitor 114 is connected to the reference ground terminal.

[0037] In this embodiment, capacitor 114 can be considered as a capacitor assembly. Capacitor 114 may include one or more capacitors, and all capacitors in capacitor 114 are connected in series, parallel, or a combination of both. Boost switch 111 and first switch 113 can be transistors or diodes. Vin is the input voltage of boost module 11 (i.e., the voltage provided by the power supply terminal), and Vcharge is the output voltage of boost module 11. When the first terminal of boost switch 111 is the source, the second terminal of boost switch 111 is the drain.

[0038] In this embodiment, the boost module 11 can enter a boost state by controlling the switching state of the boost switch 111, thereby increasing the output voltage of the boost module 11 and thus increasing the input voltage of the linear regulation module 12. For example, the boost module 11 can control the boost switch 111 to be in an on / off switching state and control the first switch 112 to be in an on state, thus enabling the boost module 11 to enter the boost state. The boost module 11 can also control its output voltage Vcharge to always be slightly higher than the battery voltage Vbat, thereby reducing the difference between the output voltage Vcharge and the battery voltage Vbat and improving charging efficiency.

[0039] Furthermore, in some embodiments, see Figure 3 The linear adjustment module 12 can be a conventional topology. In this case, the linear adjustment module can include an adjustment tube 121. The magnitude of the charging current can be adjusted through the adjustment tube 121, and the adjustment tube 121 can be controlled to bear the voltage difference between the output voltage Vcharge and the battery voltage Vbat.

[0040] In this embodiment, controlling the conduction state of the regulating transistor 121 can be regarded as controlling the degree of conduction of the regulating transistor 121. For example, controlling the regulating transistor 121 to be fully conducting, partially conducting, etc. It should be noted that in this embodiment, the regulating transistor 121 should always be conducting, so as to charge the external battery 3. The magnitude of the charging current can be controlled by controlling the degree of conduction of the regulating transistor 121.

[0041] In addition, in this embodiment, when the switching state of the boost switch 111 and the conduction state of the regulating tube 121 are controlled, the control module (the first control module 14, the second control module 17, the third control module 18, and the fourth control module 19 described in this embodiment) can obtain the output voltage Vcharge of the boost module 11, and then control the output voltage Vcharge to remain constant or change, and control the regulating tube 121 to bear the voltage difference between the output voltage Vcharge and the positive terminal of the external battery 3.

[0042] Furthermore, the linear adjustment module 12 may also include a resistor 122, and the adjustment tube 121 may include a first adjustment switch 1211 and a second adjustment switch 1212. The first end of the first adjustment switch 1211 and the first end of the second adjustment switch 1212 are respectively connected to the output node of the boost module 11, the second end of the second adjustment switch 1212 is respectively connected to the external battery 3, the third end of the first adjustment switch 1211 is connected to the third end of the second adjustment switch 1212, the resistor 122 is connected between the second end of the first adjustment switch 1211 and the reference ground terminal, and the second end of the first adjustment switch 1211 serves as the charging current sampling terminal 16.

[0043] In this embodiment, resistor 122 can be considered as a resistive component, comprising one or more resistors. All resistors in resistor 122 can be connected in series, parallel, or a combination of both. The first adjustment switch 1211 and the second adjustment switch 1212 constitute a current mirror. The electrical signal at the mirror input of the current mirror can be consistent with the output signal at the second terminal of the first adjustment switch 1211 (i.e., the current flowing through resistor 122). Alternatively, by setting the width-to-length ratio of the first adjustment switch 1211 and the second adjustment switch 1212, the current output at the second terminals of the first and second adjustment switches 1212 can be controlled to be in a certain proportion. For example, the current output at the second terminal of the first adjustment switch 1211 can be one-twentieth of the current output at the second terminal of the second adjustment switch 1212. Therefore, the current flowing through resistor 122 is generally much smaller than the charging current, and the charging current and the current flowing through resistor 122 are proportional. This proportional multiple can be determined according to actual needs; it can be set in advance or adjusted during charging.

[0044] In this embodiment, since the current output from the second terminal of the first regulating transistor 1211 can be much smaller than the current output from the second terminal of the second regulating transistor 1212, the power consumption of setting the charging current sampling terminal 16 at the second terminal of the first regulating transistor 1211 is small, thereby reducing the power consumption of the circuit.

[0045] In this embodiment, the first control module 14 is connected to the output terminal of the comparison module 13 to acquire a signal indicating that the battery voltage is between the input voltage and the first threshold voltage. The first control module 14 is also connected to the boost module 11 to control whether the boost module 11 enters a boost state. For example, the first control module 14 can be connected to the control terminal of the boost switch 111 in the boost module 11 to control the switching state of the boost switch 111. When the boost switch 111 is a transistor, its control terminal can be the gate. If the first terminal of the boost switch 111 is the source, its second terminal is the base; if the first terminal of the boost switch 111 is the base, its second terminal is the source. For example, the first control module 14 controls the boost switch 111 to be in a conduction-to-cutoff switching state and controls the first switch 112 to be in a conduction state, so that the boost module 11 enters a boost state and the charging current is in a trickle state. The first control module 14 is connected to the charging current sampling terminal 16 to collect the charging current.

[0046] In this embodiment, the battery voltage signal between the input voltage and the first threshold voltage can be a level signal, for example, the signal can be level signals of different levels. For example, when the first control module 14 detects that the signal is at the first level, it can determine that the battery voltage is between the input voltage and the first threshold voltage, and at this time, it controls the charging current to be in a trickle current state, so that the charging circuit enters trickle current mode. For example, in Figure 3 In the circuit, the first control module 14 can control the switching state of the boost switch 111 in the boost module 11 to make the charging current in a trickle state. In the trickle state, the charging circuit can ensure that the charging current is always in a small state, which improves the safety and charging rate of the external battery 3.

[0047] In the prior art, the regulating transistor 121 is usually a power transistor, and the loss of controlling the state change of the power transistor is usually large. In this embodiment, by controlling the boost switch 111, the boost module 11 is made to enter the boost state. At this time, the voltage output by the boost module 11 can be slightly greater than the battery voltage. At this time, the regulating transistor 121 is in the normally on state, without the need for the regulating transistor 121 to change state, effectively reducing the ineffective loss in the charging circuit 1 and improving the charging efficiency of the external battery 3.

[0048] Furthermore, in some embodiments, see Figure 1 , 4 The first control module 14 can also be connected to the regulating tube 121. The first control module 14 is also configured to control the conduction state of the regulating tube 121 when it receives a signal representing the battery voltage between the input voltage and the first threshold voltage, so that the charging current is in a trickle state.

[0049] In this embodiment, when the first control module 14 is connected to the regulating transistor 121, it can connect to the control terminal of the regulating transistor 121. When the regulating transistor 121 is a power transistor, its control terminal can be the base. If the first terminal of the regulating transistor 121 is the emitter, its second terminal is the collector. The first control module 14 can also simultaneously control the conduction states of the boost switch 111 and the regulating transistor 121, so that the charging current is in a trickle current state. For example, the first control module 14 can control the boost switch 111 to enter the boost state while keeping the conducting state of the regulating transistor 121 unchanged, so that the charging current is in a trickle current state. The first control module 14 can also simultaneously control the conduction states of the boost switch 111 and the regulating transistor 121, so that the charging current is in a trickle current state.

[0050] In this embodiment, the conduction states of the boost switch 111 and the regulating tube 121 can be coordinated based on the power consumption of the boost switch 111 and the power consumption of the regulating tube 121, thereby optimizing the charging circuit 1 to charge the external battery 3 in a way that minimizes power consumption and reducing energy waste.

[0051] Furthermore, in some embodiments, see Figure 4 , 5 The charging circuit 1 may also include a second control module 17, which is connected to the output terminal of the comparison module 13, the adjustment tube 121, and the charging current sampling terminal 16 respectively. The second control module 17 is configured to control the conduction state of the adjustment tube 121 when it receives a signal indicating that the battery voltage is less than the input voltage, so that the charging current is in a trickle state.

[0052] In this embodiment, similarly, the signal indicating that the battery voltage is less than the input voltage can be a signal with different voltage levels. For example, when the second control module 17 receives a signal with the second voltage level, it is considered that the battery voltage in the charging circuit is less than the input voltage. The second control module 17 is connected to the adjustment tube 121 to control the working state of the linear adjustment module 12. The second control module 17 is connected to the output terminal of the comparison module 13 to obtain the signal indicating that the battery voltage is less than the input voltage. The second control module 17 is connected to the charging current sampling terminal 16 to obtain the charging current. When the second control module 17 receives the signal indicating that the battery voltage is less than the input voltage, it can also control the working state of the adjustment tube 121 to keep the charging current in a trickle charging state.

[0053] In this embodiment, since the battery voltage is relatively low at this time, the boost module 11 does not need to enter the boost state. The boost switch 111 is in the off state, and the input voltage and the output node voltage Vcharge of the boost module 11 can be basically the same (since the first switch 113 itself has a voltage drop, the input voltage is slightly greater than the output node voltage Vcharge). Only the regulating tube 121 is controlled to achieve trickle charging. There is no need to calculate the control signal for controlling the boost switch 111, which reduces the complexity of the control charging circuit.

[0054] Furthermore, in some embodiments, see Figure 4 , 5 The second control module 17 is also connected to the boost switch 111. The second control module 17 is also configured to control the switching state of the boost switch 111 when it receives a signal indicating that the battery voltage is less than the input voltage, so that the charging current is in a trickle state.

[0055] In this embodiment, when the second control module 17 receives a signal indicating that the battery voltage is lower than the input voltage, it can simultaneously control the operating states of the boost switch 111 and the regulating transistor 121 to keep the charging current in a trickle-flow state. For example, the second control module 17 can control the operating state of the regulating transistor 121 and turn off the boost switch 111 to keep the charging current in a trickle-flow state. The second control module 17 can also control the boost module 11 to enter a boost state while keeping the operating state of the regulating transistor 121 unchanged, thus keeping the charging current in a trickle-flow state. The second control module 17 can also simultaneously control the operating states of the boost module 11 and the regulating transistor 121 to remain unchanged, thus keeping the charging current in a trickle-flow state.

[0056] In this embodiment, the conduction states of the boost switch 111 and the regulating tube 121 can be coordinated based on the power consumption of the boost switch 111 and the power consumption of the regulating tube 121, thereby optimizing the charging circuit 1 to charge the external battery 3 in a way that minimizes power consumption and reducing energy waste.

[0057] Furthermore, in some embodiments, see Figure 4 , 6 The charging circuit 1 may also include a third control module 18, which is connected to the output terminal of the comparison module 13, the boost switch 111, and the charging current sampling terminal 16, respectively. The third control module 18 is configured to control the switching state of the boost switch 111 when it receives a signal indicating that the battery voltage is less than the input voltage, so that the charging current is in a trickle state.

[0058] In this embodiment, the third control module 18 is connected to the output terminal of the comparison module 13 to acquire a signal indicating that the battery voltage is lower than the input voltage. When the third control module 18 is connected to the boost module 11, it can also be connected to the control terminal of the boost switch 111 to control the switching state of the boost switch 111. The third control module 18 is connected to the charging current sampling terminal 16 to acquire the charging current. When the third control module 18 receives a signal indicating that the battery voltage is lower than the input voltage, it can independently control the switching state of the boost switch 111 to keep the charging current in a trickle charging state.

[0059] In this embodiment, only the regulating tube 121 is controlled to achieve trickle charging, eliminating the need to specifically calculate the control signal for controlling the regulating tube 121, thus reducing the complexity of the control charging circuit.

[0060] Furthermore, in some embodiments, see Figure 4 , 7 The charging circuit 1 may also include:

[0061] The fourth control module 19 is connected to the comparison module 13, the boost switch 111, the regulating tube 121, and the charging current sampling terminal 16, respectively. The fourth control module 19 is configured to control the switching state of the boost switch 111 when it receives a signal representing the battery voltage between a first threshold voltage and a second threshold voltage, so that the charging current is in a constant current state. It is also configured to control the switching state of the boost switch 111 when it receives a signal representing the battery voltage reaching the second threshold voltage, so that the battery voltage is in a constant voltage state.

[0062] In this embodiment, similarly, the signal characterizing the battery voltage between the first threshold voltage and the second threshold voltage, and the signal characterizing the battery voltage reaching the second threshold voltage, can be a level signal. For example, when the fourth control module 19 receives the signal at a third level, it is considered that the battery voltage in the charging circuit is between the first threshold voltage and the second threshold voltage. When the fourth control module 19 receives the signal at a fourth level, it is considered that the battery voltage in the charging circuit has reached the second threshold voltage.

[0063] In this embodiment, the fourth control module 19 is connected to the comparison module 13, receiving signals representing the battery voltage between a first threshold voltage and a second threshold voltage, and signals representing the battery voltage reaching the second threshold voltage. The fourth control module 19 can be connected to the control terminals of the boost switch 111 and the regulating transistor 121 to control their conduction states. The fourth control module 19 is also connected to the charging current sampling terminal 16 to acquire the charging current. When the fourth control module 19 receives the signal representing the battery voltage between the first and second threshold voltages, it controls the charging current to be in a constant current state. For example, when the fourth control module 19 receives the signal representing the battery voltage between the first and second threshold voltages, it controls the boost module 11 to enter a boost state, keeping the regulating transistor 121 in a constant current state.

[0064] In this embodiment, when the battery voltage reaches the second threshold voltage, the battery voltage is basically the same as the second threshold voltage, indicating that the external battery 3 is close to being fully charged. At this time, the charging circuit is in a constant voltage charging state. For example, the fourth control module 19 can control the boost switch 111 to be in the on / off switching state, keeping the conducting state of the regulating tube 121 unchanged, so that the battery voltage Vbat remains unchanged, and it works in constant voltage mode. Those skilled in the art can refer to the solution provided in this embodiment and select the appropriate control circuit based on the actual power consumption, computing power, cost and other actual conditions.

[0065] Therefore, the above four control modules (i.e., the first control module 14, the second control module 17, the third control module 18, and the fourth control module 19) can achieve trickle charging or constant current charging when the input voltage Vin is less than the first voltage threshold Vth1 by controlling the switching state of the boost switch 111, or by controlling the conduction state of the regulating tube 121, or by simultaneously controlling the working states of the boost switch 111 and the regulating tube 121.

[0066] The four control modules described above achieve trickle charging or constant current charging by controlling the conduction state of the regulating transistor 121 as follows: The control module can set a reference current Iref, which is used to compare with the charging current. Based on the comparison result, the control module controls the regulating transistor 121 to ensure that the charging current output by the regulating transistor 121 is essentially consistent with the reference current Iref, thereby adjusting the charging current to the target current value. For example, the control module includes a first comparator 141. The first input terminal of the first comparator 141 acquires the reference current Iref, and the second input terminal acquires the charging current. If the charging current is greater than the reference current Iref, it indicates that the charging current is greater than the target current value. The control module then controls the regulating transistor 121, controlling the frequency and duty cycle of the output current to reduce the charging current to the reference current Iref. If the charging current is less than the reference current Iref, it indicates that the charging current is less than the target current value. The control module then controls the regulating transistor 121 to increase the charging current to the reference current Iref.

[0067] The four control modules described above achieve trickle charging or constant current charging by controlling the switching state of the boost switch 111. The control method for the boost switch 111 is similar to the control method for the regulating tube 121. For example, the control module can input a signal characterizing the charging current and a reference signal Iref to the first comparator 141. The first comparator 141 controls the switching state of the boost switch 111 based on the two input signals, thereby controlling the magnitude of the charging current and keeping it constant (i.e., keeping the charging current in trickle or constant current state).

[0068] The four control modules described above maintain a constant charging voltage by controlling the switching state of the boost switch 111. Each control module includes a second comparator 142, which receives a signal representing the charging voltage and a reference signal Vref. The second comparator 142 controls the switching state of the boost switch 111 based on the input signal, thereby controlling the battery voltage Vbat to maintain a constant voltage. For example, the signal representing the charging voltage can be acquired through a voltage divider circuit. For instance, the first terminal of the external battery 3 can be grounded through a first resistor 4 and a second resistor 5. The intermediate node between the first resistor 4 and the second resistor 5 represents the charging voltage signal. The first input terminal of the second comparator 142 is connected to the intermediate node between the first resistor 4 and the second resistor 5. The second input terminal of the second comparator 142 receives the reference signal Vref. The output terminal of the second comparator 142 is connected to the boost switch 111. Thus, the second comparator 142 controls the switching state of the boost switch 111 based on the input signal, thereby controlling the battery voltage Vbat to maintain a constant voltage.

[0069] Furthermore, in some embodiments, see Figure 8 The linear adjustment module 12 may further include a second switch 1214, a third switch 1215, and a comparison unit 1213; the first input terminal of the comparison unit 1213 is connected to the first end of the adjustment tube 121, the second input terminal of the comparison unit 1213 is connected to the second end of the adjustment tube 121, the second switch 1214 is connected between the first end of the adjustment tube 121 and the substrate end of the adjustment tube 121, the third switch 1215 is connected between the second end of the adjustment tube 121 and the substrate end of the adjustment tube 121, and the signal output by the output terminal of the comparison unit 1213 corresponds to the on / off state of the second switch 1214 and the third switch 1215.

[0070] In this embodiment, Figure 8 The charging circuit shown needs to monitor the source and drain voltages of the regulating transistor 121 in real time. The comparison unit 1213 can control the second switch 1214 and the third switch 1215 based on these voltages. The diodes between the source and drain of the regulating transistor 121 and its substrate are parasitic diodes. The second switch 1214 and the third switch 1215 control the connection between the substrate of the regulating transistor 121 and one of its source or drain terminals. For example, when the drain voltage is greater than the source voltage, the second switch 1214 is turned on, connecting the substrate of the regulating transistor 121 to its first terminal. When the drain voltage is less than the source voltage, the third switch 1215 is turned on, connecting the substrate of the regulating transistor 121 to its second terminal. This prevents reverse current from flowing from the external battery 3 through the parasitic diodes when charging stops at the input terminal of the charging circuit 1. The parasitic diodes include a first parasitic diode and a second parasitic diode. The anode of the first parasitic diode is connected to the first end of the regulating diode 121, and the anode of the second parasitic diode is connected to the second end of the regulating diode 121. The cathodes of both the first and second parasitic diodes are connected to the substrate of the regulating diode 121. In this embodiment, the conduction state of the first and second parasitic diodes can be controlled.

[0071] It should be noted that the second switch 1214 and the third switch 1215 mentioned above can be individual switches or a combination switch. For example, the second switch 1214 and the third switch 1215 can be combined as a single-pole double-throw switch.

[0072] In this embodiment, when the drain voltage is greater than the battery voltage Vbat, the second switch 1214 is turned on, connecting the substrate end of the regulating transistor 121 to the first end. When the output voltage Vcharge is less than the battery voltage Vbat, the third switch 1215 is turned on, connecting the substrate end of the regulating transistor 121 to the second end. This prevents reverse current from flowing through the parasitic diode when the charging circuit stops charging at the input end.

[0073] This embodiment also provides a charging chip, which includes the charging circuit described in the above embodiments. The specific details of this charging circuit will not be repeated here.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A charging circuit, characterized by, The charging circuit is provided with a charging current sampling end and a battery voltage sampling end, and comprises: a boost module provided with a boost switch and configured to be connected with an external power supply device; a linear regulation module provided with an adjusting tube and connected between an output node of the boost module and an external battery, wherein a current of the power supply device flows through the boost module and the linear regulation module to charge the external battery; a comparison module, a first input end of which is connected with the battery voltage sampling end, a second input end of which receives an input voltage of the boost module, a third input end of which receives a first threshold voltage greater than the input voltage, and a fourth input end of which receives a second threshold voltage greater than the first threshold voltage; a first control module, which is respectively connected with an output end of the comparison module, the boost switch and the charging current sampling end, and is configured to control a switching state of the boost switch to make the charging current in a trickle state when a signal representing that the battery voltage is between the input voltage and the first threshold voltage is received; the charging circuit further comprises: a fourth control module, which is respectively connected with the comparison module, the boost switch, the adjusting tube and the charging current sampling end, and is configured to control the switching state of the boost switch to make the charging current in a constant current state when a signal representing that the battery voltage is between the first threshold voltage and the second threshold voltage is received, and to control the switching state of the boost switch to make the battery voltage in a constant voltage state when a signal representing that the battery voltage reaches the second threshold voltage is received; the charging circuit further comprises a second control module, which is respectively connected with the output end of the comparison module, the adjusting tube and the charging current sampling end, and is configured to control a conduction state of the adjusting tube to make the charging current in a trickle state when a signal representing that the battery voltage is less than the input voltage is received.

2. The charging circuit of claim 1, wherein, The linear regulation module comprises a resistor, the adjusting tube comprises a first adjusting switch and a second adjusting switch, a first end of the first adjusting switch and a first end of the second adjusting switch are respectively connected with an output node of the boost module, a second end of the second adjusting switch is respectively connected with the external battery, a third end of the first adjusting switch is connected with a third end of the second adjusting switch, the resistor is connected between a second end of the first adjusting switch and a reference ground end, and the second end of the first adjusting switch serves as the charging current sampling end.

3. The charging circuit of claim 1, wherein, The boost module comprises a first switch, an inductor and a capacitor, a first end of the inductor is connected with a power supply end, a second end of the inductor is respectively connected with a first end of the boost switch and a first end of the first switch, a second end of the boost switch is connected with a reference ground end, and a second end of the first switch is respectively connected with the linear regulation module and a first end of the capacitor, a second end of the capacitor is connected with the reference ground end.

4. The charging circuit of claim 1, wherein, The linear regulation module further comprises a second switch, a third switch and a comparison unit; a first input end of the comparison unit is connected with the first end of the regulating tube, a second input end of the comparison unit is connected with the second end of the regulating tube, the second switch is connected between the first end of the regulating tube and the substrate end of the regulating tube, the third switch is connected between the second end of the regulating tube and the substrate end of the regulating tube, and an output end of the comparison unit outputs a signal corresponding to on-off states of the second switch and the third switch.

5. A charging chip, characterized by, A charging circuit comprising the linear regulator of any one of claims 1 to 4.

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