CN114362323A - Charging circuit and chip - Google Patents

Abstract

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

Description

A charging circuit and chip

technical field

The invention belongs to the technical field of integrated circuits, and in particular relates to a charging circuit and a chip.

Background technique

At present, in the field of lithium battery charging, for applications where the input voltage is less than the full voltage of the battery, the input voltage is usually boosted and then the battery is charged. The switch-mode boost circuit can achieve higher power utilization efficiency and faster charging. time. However, in the prior art, in the trickle charging stage, a boost circuit is used to raise the output voltage to a fixed value, and then a charging circuit is used to charge the battery with a certain small current, and the battery voltage gradually increases with charging. At this stage, since the voltage after boosting is a fixed value, when the battery voltage differs greatly from the fixed voltage value, the charging efficiency is relatively low.

SUMMARY OF THE INVENTION

Aiming at the defects in the prior art, the present invention provides a charging circuit and a chip, which improve the charging efficiency of an external battery.

An embodiment of the present invention provides a charging circuit. The charging circuit is provided with a charging current sampling terminal and a battery voltage sampling terminal. The charging circuit includes:

a boosting module provided with a boosting switch, configured to be connected to an external power supply device;

A linear regulation module with a regulating tube is connected between the output node of the boost module and the external battery, and the current of the power supply device flows through the boost module and the linear regulation module to charge the external battery;

The comparison module has a first input terminal connected to the battery voltage sampling terminal, a second input terminal of which receives the input voltage of the boosting module, a third input terminal of which receives a first threshold voltage greater than the input voltage, and a fourth input terminal of which receives a voltage greater than the input voltage. a second threshold voltage of the first threshold voltage;

The first control module is respectively connected to the output end of the comparison module, the boost switch, and the charging current sampling end, and the first control module is configured to receive a signal indicating that the battery voltage is between the input voltage and the first threshold voltage, and then control the boosting. The on-off state of the voltage switch, so that the charging current is in a trickle state.

Embodiments of the present invention further provide a charging chip, where the charging chip includes the charging circuit provided by the above embodiments.

The charging circuit and chip provided by the present invention make the boosting module enter the boosting state by controlling the boosting switch. At this time, the voltage output by the boosting module can be just slightly larger than the battery voltage. At this time, the regulating tube is in a normally on state, while There is no need to change the state of the adjustment tube, effectively reducing the ineffective loss in the charging circuit, and improving the charging efficiency of the external battery.

Description of drawings

In order to illustrate the specific embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that are required to be used in the description of the specific embodiments or the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. In the drawings, each element or section is not necessarily drawn to actual scale.

FIG. 1 is a schematic block diagram of a charging circuit provided by an embodiment.

FIG. 2 is a schematic diagram of various stages in the charging process.

FIG. 3 is a circuit diagram of a charging circuit provided by an embodiment.

FIG. 4 is a schematic diagram of charging modes at various stages in the charging process.

FIG. 5 is a schematic block diagram of a charging circuit including a second control module provided by an embodiment.

FIG. 6 is a schematic block diagram of a charging circuit including a third control module provided by an embodiment.

FIG. 7 is a schematic block diagram of a charging circuit including a fourth control module provided by an embodiment.

FIG. 8 is another circuit diagram of the charging circuit provided by the embodiment.

Detailed ways

Embodiments of the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention. It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the usual meanings understood by those skilled in the art to which the present invention belongs.

It is to be understood that, when used in this specification and the appended claims, the terms "comprising" and "comprising" indicate the presence of the described features, integers, steps, operations, elements and/or components, but do not exclude one or The presence or addition of a number of other features, integers, steps, operations, elements, components, and/or sets thereof.

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

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

Example:

A charging circuit 1, see FIG. 1, the charging circuit 1 is provided with a charging current sampling terminal 16 and a battery voltage sampling terminal 15, and the charging circuit 1 includes:

The boosting module 11 provided with the boosting switch 111 is arranged to be connected to the external power supply device 2 .

The linear regulating module 12 with the regulating tube 121 is connected between the output node of the boosting module 11 and the external battery 3 . The current of the power supply device 2 flows through the boosting module 11 and the linear regulating module 12 charges the external battery 3 .

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

The first control module 14, 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. A signal between the threshold voltages controls the switching state of the boost switch 111 so that the charging current is in a trickle state.

It should be noted that the "external power supply device 2" described in this embodiment is "external" relative to the charging circuit 1, not the "external" of the carrier where the charging circuit 1 is located. Similarly, the following "external battery 3" is "external" with respect to the charging circuit 1, and does not limit the specific position of the "external battery 3". Similarly, in this embodiment, the following external energy storage devices, external peripheral circuits, external electronic components and the like are the same.

In this embodiment, the charging circuit 1 may be connected between the power supply device 2 and the external battery 3 , and convert 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, and the like. 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 cadmium-nickel battery, etc. The type of the external battery 3 is not specifically limited here. In addition, the external battery can also be regarded as a battery assembly, including one or more charging units, all charging units in the external battery 3 can be connected in series, parallel or a combination of the two, and output a positive electrode and a negative electrode, The structure of the external battery 3 is not specifically limited here.

It should be noted that, since the working process of the charging circuit 1 needs to be controlled based on the charging current and the battery voltage, the charging circuit 1 must include a charging current sampling terminal 16 and a battery voltage sampling terminal 15 , through which the charging current sampling terminal 16 Connect to obtain the charging current, and obtain the battery voltage by connecting with the battery voltage sampling terminal 15 . The charging current sampling terminal 16 is configured to acquire a signal representing the charging current in the charging circuit 1 , and the battery voltage sampling terminal 15 is configured to acquire a signal representing the battery voltage in the charging circuit 1 . For example, when the battery voltage of the battery needs to be obtained, the battery voltage can be obtained by calculating the difference between the positive voltage value and the negative electrode voltage value, or the negative electrode of the battery can be connected to the ground terminal, and the battery voltage can be obtained by obtaining the positive voltage value. The voltage used to characterize the battery voltage (for example, obtain a voltage that has a linear relationship and a functional relationship with the battery voltage). There is no specific limitation on the method of obtaining the battery voltage. Similarly, the setting point of the battery voltage sampling terminal 15 There are no specific restrictions. Similarly, there is no specific limitation on the setting point of the charging current sampling terminal 16 .

In this embodiment, referring to FIG. 2 , the charging process of the external battery 3 generally needs to go through three stages: a trickle mode, a constant current mode, and a constant voltage mode. When the battery voltage is small, enter the trickle mode a, use a small charging current to charge, and the battery voltage gradually increases. When the battery voltage increases to exceed a certain threshold, enter the constant current mode b to ensure that the charging current is constant for charging, and the battery voltage gradually increases. When the battery is close to being fully charged, it enters the constant voltage mode c, and is charged with a constant voltage, the battery voltage is basically unchanged, and the rechargeable battery gradually decreases. This charging method can take into account both the charging safety and the charging rate.

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

It should be noted that the charging circuit 1 provided in this embodiment is suitable for the case where the input voltage Vin is less than the first threshold voltage Vth1. In the charging circuit 1, the second threshold voltage Vth2 is greater than the first threshold voltage Vth1, and the first threshold voltage The specific values of Vth1 and the second threshold voltage Vth2 can be determined according to actual requirements. The charging circuit 1 includes, but is not limited to, a Buck-Boost charging circuit, a Sepic charging circuit, a Cuk charging circuit, a Zeta charging circuit, and the like.

Further, in some embodiments, referring to FIG. 3 , the boosting module 11 may be a common boosting topology. For example, the boosting module 11 may further include a first switch 113 , an inductor 112 , and a capacitor 114 . One end is connected to the power supply end, 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, the first The second end of the 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.

In this embodiment, the capacitor 114 may be regarded as a capacitive component, the capacitor 114 may include one or more capacitors, and all the capacitors in the capacitor 114 are obtained by connecting in series, in parallel, or a combination of the two. The boost switch 111 and the first switch 113 may be transistors or diodes. Vin is the input voltage of the boosting module 11 (ie, the voltage provided by the power supply terminal), and Vcharge is the output voltage of the boosting module 11 . When the first terminal of the boost switch 111 is the source, the second terminal of the boost switch 111 is the drain.

In this embodiment, the boosting module 11 can enter the boosting state through the switching state of the boosting switch 111 to increase the output voltage of the boosting module 11 , thereby increasing the input voltage of the linear adjustment module 12 . For example, the boosting module 11 may control the boosting switch 111 to be in the on-off switching state, and control the first switch 112 to be in the conducting state, so that the boosting module 11 enters the boosting state. The boosting module 11 can control the state where the output voltage Vcharge is always slightly larger than the battery voltage Vbat, thereby reducing the difference between the output voltage Vcharge and the battery voltage Vbat and improving the charging efficiency.

Further, in some embodiments, referring to FIG. 3 , the linear adjustment module 12 may be of a conventional topology, and at this time, the linear adjustment module may include an adjustment tube 121 , through which the size of the charging current can be adjusted and controlled The regulating tube 121 bears the voltage difference between the output voltage Vcharge and the battery voltage Vbat.

In this embodiment, controlling the conduction state of the adjustment tube 121 can be regarded as controlling the conduction degree of the adjustment tube 121 . For example, control the adjustment tube 121 to be fully conductive, semi-conductive, or the like. It should be noted that, in this embodiment, the adjustment tube 121 should always be turned on, so that the external battery 3 can be charged, and the size of the charging current can be controlled by controlling the conduction degree of the adjustment tube 121 .

In addition, in this embodiment, when controlling the switching state of the boost switch 111 and the conducting state of the regulating tube 121, the control modules (the first control module 14, the second control module 17, the The third control module 18 and the fourth control module 19 ) can obtain the output voltage Vcharge of the boosting module 11 , and then control the output voltage Vcharge to keep constant or change, and control the regulating tube 121 to assume the difference between the output voltage Vcharge and the positive electrode of the external battery 3 . differential pressure.

Further, the linear adjustment module 12 may further include a resistor 122 , 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 terminal of the first adjustment switch 1211 and the reference ground terminal, and the second terminal of the first adjustment switch 1211 serves as the charging current sampling terminal 16 .

In this embodiment, the resistor 122 can be regarded as a resistance component, the resistor 122 includes one or more resistors, and all the resistors in the 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 of the mirror input part of the current mirror can be consistent with the output signal of the second end of the first adjustment switch 1211 (ie the current flowing through the resistor 122 ), or the width of the first adjustment tube 1211 and the second adjustment tube 1212 can be set by setting length ratio, control the current output by the second end of the first adjusting tube 1211 and the second adjusting tube 1212 to be in a certain ratio, for example, make the current output by the second end of the first adjusting tube 1211 equal to One-twentieth of the current output from the two terminals, therefore, the current flowing through the resistor 122 is generally much smaller than the charging current, and the charging current and the current flowing through the resistor 122 are proportional. The proportional multiple can be determined according to the actual demand, and the proportional multiple can be set in advance or adjusted during the charging process.

In this embodiment, since the current output by the second end of the first adjusting tube 1211 can be much smaller than the current output by the second end of the second adjusting tube 1212 , the charging current sampling terminal 16 is set at the first adjusting tube The power consumption used by the second terminal of 1211 is small, which can reduce the power consumption of the circuit.

In this embodiment, the first control module 14 is connected to the output end of the comparison module 13 to obtain a signal of the battery voltage between the input voltage and the first threshold voltage. The first control module 14 is connected to the boosting module 11 to control the boosting Whether the boosting module 11 enters the boosting state, for example, the first control module 14 may be connected to the control terminal of the boosting switch 111 in the boosting module 11 to control the switching state of the boosting 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, and the second terminal is the base; if the first terminal of the boost switch 111 is the base , and its second end is the source. For example, the first control module 14 controls the boost switch 111 to be in the on-off switching state, and controls the first switch 112 to be in the on state, so that the boost module 11 enters the boost state and the charging current is in the trickle state. The first control module 14 is connected to the charging current sampling terminal 16 for collecting the charging current.

In this embodiment, the signal of the battery voltage between the input voltage and the first threshold voltage may be a level signal, for example, the signal may be a level signal of different levels. For example, when the first control module 14 detects that the signal is at the first level, it can obtain that the battery voltage is between the input voltage and the first threshold voltage. At this time, the charging current is controlled to be in a trickle state, so that the charging circuit enters the trickle mode. . For example, in the circuit of FIG. 3 , 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, and the charging circuit can ensure that the charging current is always in the trickle state. The smaller state improves the safety and charging rate of the external battery 3 charging.

In the prior art, the regulating tube 121 is usually a power tube, and the loss of controlling the state change of the power tube is usually large. In this embodiment, the boosting switch 111 is controlled to make the boosting module 11 enter the boosting state. The voltage output by the boosting module 11 can be just slightly larger than the battery voltage. At this time, the regulating tube 121 is in a normally-on state without the need for a state change of the regulating tube 121, which effectively reduces the ineffective loss in the charging circuit 1 and improves the external battery 3 charging efficiency.

Further, in some embodiments, referring to FIGS. 1 and 4 , the first control module 14 may also be connected to the regulating tube 121 , and the first control module 14 is further configured to receive a signal representing the battery voltage between the input voltage and the first threshold voltage The signal between them controls the conduction state of the pass transistor 121 so that the charging current is in a trickle state.

In this embodiment, in this embodiment, when the first control module 14 is connected to the adjustment tube 121, it can be connected to the control end of the adjustment tube 121, and when the adjustment tube 121 is a power tube, its control end can be the base electrode, If the first end of the adjusting tube 121 is the emitter electrode, the second end thereof is the collector electrode. The first control module 14 can also control the conduction state of the boost switch 111 and the regulating tube 121 at the same time, so that the charging current is in a trickle state. For example, the first control module 14 may control the boost switch 111 to enter a boost state, and keep the conduction state of the regulating tube 121 unchanged, so that the charging current is in a trickle state. The first control module 14 can also control the conduction state of the boost switch 111 and the regulating tube 121 at the same time, so that the charging current is in a trickle state.

In this embodiment, the conduction states of the boost switch 111 and the adjustment transistor 121 can be coordinated and controlled based on the power consumption of the boost switch 111 and the power consumption of the adjustment transistor 121, so that the power consumption of the charging circuit 1 is preferably smaller. way to charge the external battery 3, reducing energy waste.

Further, in some embodiments, referring to FIGS. 4 and 5 , the charging circuit 1 may further include a second control module 17 , the output end of the second control module 17 and the comparison module 13 , the adjusting tube 121 , and the charging current sampling end 16 are respectively connected, the second control module 17 is configured to receive a signal indicating that the battery voltage is smaller than the input voltage and then control the conduction state of the regulating tube 121 so that the charging current is in a trickle state.

In this embodiment, for the same reason, the signal representing that the battery voltage is lower than the input voltage may be a level signal of different levels. For example, when the level of the signal received by the second control module 17 is the second level, it is considered that at this time The battery voltage in the charging circuit is less than the input voltage. The second control module 17 is connected with 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 end of the comparison module 13, and acquires a signal representing that the battery voltage is lower 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 a signal indicating that the battery voltage is lower than the input voltage, it can also control the working state of the regulating tube 121 so that the charging current of the charging circuit is in a trickle state.

In this embodiment, since the battery voltage is small at this time, the boosting module 11 does not need to enter the boosting state, so that the boosting switch 111 is in the off state, and the input voltage and the output node voltage Vcharge of the boosting module 11 can be basically the same ( Since the first switch 113 itself has a voltage drop, the input voltage is slightly larger than the output node voltage Vcharge), only the regulator tube 121 is controlled to achieve trickle charging, and there is no need to specially calculate the control signal used to control the boost switch 111, reducing the control charging circuit. Complexity.

Further, in some embodiments, referring to FIGS. 4 and 5 , the second control module 17 is further connected to the boost switch 111 , and the second control module 17 is further configured to control the boost switch after receiving a signal indicating that the battery voltage is less than the input voltage. The switching state of the switch 111 is pressed, so that the charging current is in a trickle state.

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 also control the working states of the voltage regulating switch 111 and the regulating tube 121 at the same time, so that the charging current of the charging circuit is in a trickle state state. For example, the second control module 17 can control the working state of the regulator tube 121 and the boost switch 111 to be turned off, so that the charging current is in a trickle state. The second control module 17 can also control the boosting module 11 to enter a boosting state, and keep the working state of the regulating tube 121 unchanged, so that the charging current is in a trickle state. The second control module 17 can also control the working states of the boosting module 11 and the regulating tube 121 to remain unchanged at the same time, so that the charging current is in a trickle state.

In this embodiment, the conduction states of the boost switch 111 and the adjustment transistor 121 can be coordinated and controlled based on the power consumption of the boost switch 111 and the power consumption of the adjustment transistor 121, so that the power consumption of the charging circuit 1 is preferably smaller. way to charge the external battery 3, reducing energy waste.

Further, in some embodiments, referring to FIGS. 4 and 6 , the charging circuit 1 may further include a third control module 18 , the output terminal of the third control module 18 and the comparison module 13 , the boost switch 111 , and the charging current sampling terminal 16 respectively connected, the third control module 18 is configured to control the switching state of the boost switch 111 after receiving a signal representing that the battery voltage is less than the input voltage, so that the charging current is in a trickle state.

In this embodiment, the third control module 18 is connected to the output end of the comparison module 13 to obtain a signal indicating that the battery voltage is less than the input voltage. The control terminal is connected 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 obtain the charging current. The third control module 18 can independently control the switching state of the boost switch 111 when receiving a signal indicating that the battery voltage is lower than the input voltage, so that the charging current is in a trickle state.

In this embodiment, only the regulating tube 121 is controlled to realize trickle charging, and there is no need to specially calculate the control signal for controlling the regulating tube 121, thereby reducing the complexity of the control charging circuit.

Further, in some embodiments, referring to FIGS. 4 and 7 , the charging circuit 1 may further include:

The fourth control module 19 is connected to the comparison module 13, the boost switch 111, the adjusting tube 121, and the charging current sampling terminal 16 respectively. The signal between the voltages controls the switching state of the boost switch 111 so that the charging current is in a constant current state, and is further configured to control the switching state of the boost switch 111 upon receiving a signal indicating that the battery voltage reaches the second threshold voltage, so that the battery voltage is in a constant voltage state.

In this embodiment, similarly, the signal representing the battery voltage between the first threshold voltage and the second threshold voltage and the signal representing the battery voltage reaching the second threshold voltage may be level signals. For example, when the level of the signal received by the fourth control module 19 is the third level, it is considered that the battery voltage in the charging circuit at this time is between the first threshold voltage and the second threshold voltage. When the level of the signal received by the fourth control module 19 is the fourth level, it is considered that the battery voltage in the charging circuit reaches the second threshold voltage at this time.

In this embodiment, the fourth control module 19 is connected to the comparison module 13, and receives a signal indicating that the battery voltage is between the first threshold voltage and the second threshold voltage, and a signal indicating that the battery voltage reaches the second threshold voltage. The fourth control module 19 can be connected to the control terminals of the boost switch 111 and the regulating tube 121 to control the conduction state of the boost switch 111 and the regulating tube 121, and the fourth control module 19 is connected to the charging current sampling terminal 16 to obtain the charging current . The fourth control module 19 controls the charging current to be in a constant current state when receiving a signal indicating that the battery voltage is between the first threshold voltage and the second threshold voltage. For example, when the fourth control module 19 receives a signal indicating that the battery voltage is between the first threshold voltage and the second threshold voltage, it controls the boosting module 11 to enter the boosting state, keeps the conduction state of the regulating tube 121 unchanged, and controls The charging current is in a constant current state.

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 nearly fully charged, and the control 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, keep the on-state of the regulating tube 121 unchanged, keep the battery voltage Vbat unchanged, and work in the constant voltage mode, those skilled in the art can refer to In the solution provided in this embodiment, a corresponding control circuit is selected based on actual conditions such as actual power consumption, computing power, and cost.

It can be seen that the above four control modules (ie, the first control module 14, the second control module 17, the third control module 18, and the fourth control module 19), for the case where the input voltage Vin is less than the first voltage threshold Vth1, can be Trickle charging or constant current charging can be realized by controlling the switching state of the boost switch 111 , trickle charging or constant current charging can also be realized by controlling the conduction state of the regulating tube 121 , or by simultaneously controlling the boosting switch 111 and the regulating tube The working state of 121 realizes trickle charging or constant current charging.

The above four control modules implement trickle charging or constant current charging by controlling the conduction state of the adjusting tube 121 as follows: the control module can set the reference current Iref, the reference current Iref can be used to compare with the charging current, and the control module can set the reference current Iref according to the comparison. As a result, the regulating tube 121 is controlled so that the charging current output by the regulating tube 121 is basically the same as the reference current Iref, thereby realizing the function of 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 obtains the reference current Iref, and the second input terminal of the first comparator 141 obtains the charging current. If the charging current is greater than the reference current Iref, the charging current is indicated. When the current value is greater than the target value, the control module controls the regulating tube 121 to control the frequency and duty ratio of the output current of the regulating tube 121 , so that the charging current is reduced to the reference current Iref. If the charging current is less than the reference current Iref, it means that the charging current is less than the target current value, and the control module controls the regulating tube 121 to increase the charging current to the reference current Iref.

The above four control modules realize trickle charging or constant current charging by controlling the switching state of the boost switch 111 . The control method for the boost switch 111 by the control module is similar to the control method for the regulating tube 121 . For example, the control module can input the signal used to represent the charging current and the reference signal Iref to the first comparator 141, and the first comparator 141 controls the switching state of the boost switch 111 according to the two input signals, thereby controlling the magnitude of the charging current , keep the charging current constant (ie, make the charging current a trickle state or a constant current state).

The above four control modules control the switching state of the boost switch 111 so that the charging voltage is in a constant voltage state. The control module includes a second comparator 142, the second comparator 142 can receive a signal representing the charging voltage and a reference signal Vref, the second comparator 142 controls the switching state of the boost switch 111 according to the input signal, and then passes the boost switch 111 The magnitude of the battery voltage Vbat is controlled to keep the battery voltage Vbat constant. For example, the signal representing the charging voltage can be collected through a voltage divider circuit. For example, the first end of the external battery 3 can be grounded through the first resistor 4 and the second resistor 5, and the intermediate node between the first resistor 4 and the second resistor 5 is the voltage representing the charging voltage. signal, the first input terminal of the second comparator 142 is connected to the intermediate node of the first resistor 4 and the second resistor 5, the second input terminal of the second comparator 142 receives the reference signal Vref, and the output terminal of the second comparator 142 The boost switch 111 is connected, so that the second comparator 142 controls the switching state of the boost switch 111 according to the input signal, and then controls the battery voltage Vbat through the boost switch 111 to keep the battery voltage Vbat constant.

Further, in some embodiments, referring to FIG. 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 end of the comparison unit 1213 and the first end of the adjustment tube 121 The second input end 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, and the third switch 1215 is connected to Between the second end of the adjustment tube 121 and the substrate end of the adjustment tube 121 , the signal output by the output end of the comparison unit 1213 corresponds to the on-off state of the second switch 1214 and the third switch 1215 .

In this embodiment, the charging circuit shown in FIG. 8 needs to detect the source voltage and drain voltage of the adjusting tube 121 in real time, and the comparing unit 1213 can control the second switch 1214 according to the source voltage and drain voltage of the adjusting tube 121 . and the third switch 1215. The diodes between the source and drain of the pass transistor 121 and the substrate end are parasitic body diodes, and the second switch 1214 and the third switch 1215 are used to control the substrate end of the pass tube 121 and the source and the source of the pass tube 121 . one of the drain connections. For example, when the drain voltage is greater than the source voltage, the second switch 1214 is turned on, so that the substrate end of the pass transistor 121 is connected to the first end of the pass transistor 121 . When the drain voltage is less than the source voltage, the third switch 1215 is turned on, so that the substrate end of the adjustment transistor 121 is connected to the second end of the adjustment transistor 121, which can prevent the charging circuit 1 from charging when the input end stops charging. The external battery 3 is backflowed through the parasitic body diode. The parasitic diode includes a first parasitic diode and a second parasitic diode. The anode of the first parasitic diode is connected to the first end of the adjustment tube 121 , the anode of the second parasitic diode is connected to the second end of the adjustment tube 121 , and the first parasitic diode is connected to the second end of the adjustment tube 121 . The cathode of the diode and the cathode of the first parasitic diode are both connected to the substrate of the pass transistor 121 . In this embodiment, the conduction states of the first parasitic diode and the second parasitic diode can be controlled.

It should be noted that the above-mentioned second switch 1214 and third switch 1215 may be a single switch, respectively, or may be a combination switch. For example, the second switch 1214 and the third switch 1215 may be combined as a single-pole double-throw switch.

In this embodiment, when the drain voltage is greater than the battery voltage Vbat, the second switch 1214 is turned on, so that the substrate end of the pass transistor 121 is connected to the first end. When the output voltage Vcharge is less than the battery voltage Vbat, the third switch 1215 is turned on, so that the substrate terminal of the adjustment tube 121 is connected to the second terminal, which can prevent the battery from passing through the parasitic body diode when the charging circuit stops charging at the input terminal. Backflow occurs.

This embodiment also provides a charging chip, where the chip includes the charging circuit described in the above embodiments. The specific content of the charging circuit will not be repeated here.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. The scope of the invention should be included in the scope of the claims and description of the present invention.

Claims (10)

1. A charging circuit, characterized in that, charging circuit is equipped with charging current sample terminal and battery voltage sample terminal, charging circuit includes:

a boost module provided with a boost switch, configured to be connected to an external power supply device;

the linear regulating module is provided with a regulating tube and is connected between an output node of the boosting module and an external battery, and the current of the power supply device flows through the boosting module and the linear regulating 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 the input voltage of the boosting module, a third input end of which receives a first threshold voltage which is larger than the input voltage, and a fourth input end of which receives a second threshold voltage which is larger than the first threshold voltage;

a first control module, connected to the output of the comparison module, the boost switch, and the charging current sampling terminal, respectively, wherein the first control module is configured to receive a signal indicating that the battery voltage is between the input voltage and the first threshold voltage, and then control the switching state of the boost switch, so that the charging current is in a trickle state.

2. The charging circuit of claim 1, wherein the first control module is further coupled to the regulating tube, and wherein the first control module is further configured to receive a signal indicative of the battery voltage being between the input voltage and the first threshold voltage to control the conducting switch state of the regulating tube such that the charging current is in a trickle state.

3. The charging circuit of claim 1, further comprising a second control module, the second control module being connected to the output of the comparison module, the regulating tube, and the charging current sampling terminal, respectively, the second control module being configured to control the conduction state of the regulating tube to make the charging current in the trickle state upon receiving a signal indicating that the battery voltage is less than the input voltage.

4. The charging circuit of claim 3, wherein the second control module is further coupled to the boost switch, the second control module further configured to control a switching state of the boost switch to place the charging current in a trickle state upon receiving a signal indicative of the battery voltage being less than the input voltage.

5. The charging circuit of claim 1, further comprising a third control module, wherein the third control module is connected to the output of the comparison module, the boost switch, and the charging current sampling terminal, and wherein the third control module is configured to control the switching state of the boost switch to maintain the charging current in the trickle state when receiving a signal indicating that the battery voltage is less than the input voltage.

6. The charging circuit of claim 1, further comprising:

the fourth control module is configured to receive a signal representing that the battery voltage is between the first threshold voltage and the second threshold voltage and control the switching state of the boost switch so as to enable the charging current to be in a constant current state, and is also configured to receive a signal representing that the battery voltage reaches the second threshold voltage and control the switching state of the boost switch so as to enable the battery voltage to be in a constant voltage state.

7. The charging circuit according to any one of claims 1 to 6, wherein the linear regulation module includes a resistor, the regulation tube includes a first regulation switch and a second regulation switch, a first terminal of the first regulation switch and a first terminal of the second regulation switch are respectively connected to the output node of the boost module, a second terminal of the second regulation switch is respectively connected to the external battery, a third terminal of the first regulation switch is connected to a third terminal of the second regulation switch, the resistor is connected between the second terminal of the first regulation switch and a reference ground terminal, and the second terminal of the first regulation switch serves as the charging current sampling terminal.

8. The charging circuit according to any one of claims 1 to 6, wherein the boost module comprises a first switch, an inductor, and a capacitor, a first end of the inductor is connected to a power supply terminal, a second end of the inductor is connected to a first end of the boost switch and a first end of the first switch, respectively, a second end of the boost switch is connected to a reference ground terminal, a second end of the first switch is connected to the linear regulation module and a first end of the capacitor, respectively, and a second end of the capacitor is connected to the reference ground terminal.

9. The charging circuit according to any one of claims 1 to 6, wherein the linear regulation module further comprises a second switch, a third switch, a comparison unit; the first input end of the comparison unit is connected with the first end of the adjusting tube, the second input end of the comparison unit is connected with the second end of the adjusting tube, the second switch is connected between the first end of the adjusting tube and the substrate end of the adjusting tube, the third switch is connected between the second end of the adjusting tube and the substrate end of the adjusting tube, and a signal output by the output end of the comparison unit corresponds to the on-off states of the second switch and the third switch.

10. A charging chip comprising the charging circuit of any one of claims 1 to 9.

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