CN109638917B - Charging circuit and electronic equipment - Google Patents
Charging circuit and electronic equipment Download PDFInfo
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- CN109638917B CN109638917B CN201811577424.9A CN201811577424A CN109638917B CN 109638917 B CN109638917 B CN 109638917B CN 201811577424 A CN201811577424 A CN 201811577424A CN 109638917 B CN109638917 B CN 109638917B
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- H02J7/0026—
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
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Abstract
The application provides a charging circuit and electronic equipment, which comprise a reference voltage selection unit and a switch charging unit connected with the reference voltage selection unit; wherein: a reference voltage selecting unit for selecting a lowest potential between a power supply voltage terminal and a ground terminal as a reference voltage, and outputting the reference voltage; the switch charging unit is used for receiving the reference voltage and outputting a control signal to control the on-off of the communication between the power supply voltage end of the switch charging unit and the charging main unit of the switch charging unit according to the difference value between the voltage of the power supply voltage end and the reference voltage; if the voltage of the power supply voltage end is equal to the reference voltage, the control signal controls the communication between the power supply voltage end and the charging main unit of the switch charging unit to be disconnected.
Description
Technical Field
The present application relates to the field of integrated circuits, and in particular, to a charging circuit and an electronic device.
Background
With the development of science and technology, the charging modes of portable electronic products are more and more diversified. The existing quick charging mode mainly comprises low-voltage large-current quick charging and high-voltage quick charging. The current high-voltage quick charge is realized by adopting a mode of improving the charging voltage. The existing high-voltage charging voltage supports 9V and 12V high-voltage charging in addition to basic 5V normal-voltage charging. In the existing high-voltage quick charging circuit structure, the switching tubes in the circuit are all high-voltage tubes because of the need of supporting high-voltage charging. Because the switching tube is a high-voltage tube, the switching tube can be connected with a diode in parallel between the source electrode and the drain electrode to form a switching tube body. In the high-voltage quick charging circuit structure, because the diode orientations of the different switch tube bodies are different, when the switch charging chip is not used, the power supply voltage end and the output port of the switch charging chip are mutually isolated, and a leakage path is prevented from being formed between the power supply voltage end and the output port.
When the portable electronic product is charged by using the switch charging chip in a high-voltage rapid charging mode, positive and negative surge voltages are generated at the power supply voltage end by hot plug of the power supply voltage end in the switch charging chip, so that the power supply voltage end of the existing switch charging chip can generally resist DC-2V or even higher voltage when being set. The positive-direction surge is a surge propagating from the power supply voltage terminal toward the internal circuit of the switch charging chip, and the negative-direction surge is a surge propagating from the internal circuit of the switch charging chip toward the power supply voltage terminal.
For the surge in the negative direction, the surge is usually ignored in the design of an integrated circuit, and according to data investigation, the proportion of the damage of a switch charging chip caused by the negative surge of a power supply voltage terminal to the damage of the chip is higher and higher. Therefore, providing a charging circuit to avoid the damage of the negative surge generated at the power supply voltage terminal to the switch charging chip is a technical problem to be solved by those skilled in the art.
Disclosure of Invention
Based on the defects in the prior art, the application provides a charging circuit to cut off the propagation of negative surge when the negative voltage occurs at the power supply voltage end, so as to avoid the damage of the negative surge to the switch charging chip.
In order to achieve the above object, the embodiment of the present application provides the following technical solutions:
the first aspect of the present application discloses a charging circuit comprising:
the switching charging device comprises a reference voltage selection unit and a switch charging unit connected with the reference voltage selection unit; wherein:
the reference voltage selecting unit is used for selecting the lowest potential between a power supply voltage end and a grounding end as a reference voltage and outputting the reference voltage;
the switch charging unit is used for receiving the reference voltage and outputting a control signal to control the on-off of the communication between the power supply voltage end of the switch charging unit and the charging main unit of the switch charging unit according to the difference value between the voltage of the power supply voltage end and the reference voltage; and if the voltage of the power supply voltage end is equal to the reference voltage, the control signal controls the communication between the power supply voltage end and the charging main unit of the switch charging unit to be disconnected.
Optionally, in the above charging circuit, the reference voltage selecting unit includes:
a first transistor and a second transistor which are NMOS transistors;
the control end of the first transistor is connected with the grounding end, the first end receives the voltage of the power supply voltage end, and the second end of the first transistor is connected with the second end of the second transistor;
the control end of the second transistor receives the voltage of the power supply voltage end, and the first end of the second transistor is connected with the grounding end;
and the common terminal of the first transistor and the second transistor is used as an output port of the reference selection unit to output the reference voltage.
Optionally, in the above charging circuit, the switch charging unit is configured to control on-off of a switching tube disposed between the power supply voltage end and the charging main unit of the switch charging unit, so as to control on-off of communication between the power supply voltage end of the switch charging unit and the charging main unit of the switch charging unit.
Optionally, in the above charging circuit, a driving unit in the switch charging unit is connected to the reference voltage selecting unit, and is configured to receive the reference voltage, and control on-off of the switching tube according to a difference between the voltage of the power supply voltage terminal and the reference voltage.
Optionally, in the above charging circuit, the driving unit includes:
one end of the resistor is connected with the power supply voltage end, and the other end of the resistor is grounded through a voltage stabilizing diode;
the first input end of the charge pump is connected with the resistor, and the second input end of the charge pump is connected with the power supply voltage end; a third transistor with a first end connected with the output end of the charge pump, wherein the third transistor is an NMOS transistor, a control end of the third transistor receives an enabling signal, and a second end receives the reference voltage;
and the common end of the charge pump and the third transistor is used as an output port of the driving unit and is used for connecting the control end of the switching tube.
Optionally, in the charging circuit, if the switch charging unit outputs a control signal to control the switch transistor to be in an off state, the enable signal received by the control end of the third transistor controls the third transistor to be turned on.
Optionally, in the above charging circuit, the switching tube includes: a transistor with a diode.
Optionally, in the charging circuit, the switching tube is further connected with a diode; the positive electrode of the diode is connected with the second end of the switching tube, and the negative electrode of the diode is connected with the first end of the switching tube.
The second aspect of the present application discloses an electronic device, comprising: a charging circuit as claimed in any one of the first aspects of the present application.
As can be seen from the above technical solution, in the charging circuit provided by the present application, the reference voltage selecting unit is configured to select a lowest potential between the power supply voltage terminal and the ground terminal as a reference voltage, and output the reference voltage; the switch charging unit receives the reference voltage, and outputs a control signal to control the on-off of the communication between the power supply voltage end of the switch charging unit and the charging main unit of the switch charging unit according to the difference value between the voltage of the power supply voltage end and the reference voltage; and if the voltage of the power supply voltage end is equal to the reference voltage, the control signal controls the communication between the power supply voltage end in the switch charging unit and the charging main unit of the switch charging unit to be disconnected. When negative pressure occurs at the power supply voltage end, the lowest potential selected by the reference voltage selection unit is the voltage of the power supply voltage end, the voltage of the power supply voltage end is equal to the reference voltage, and then the control signal controls the communication between the power supply voltage end in the switch charging unit and the charging main unit of the switch charging unit to be disconnected, so that the propagation of negative surge is blocked, and the damage to the switch charging chip caused by the negative pressure of the power supply voltage end is avoided.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present application, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a circuit block diagram of a charging circuit in a conventional switch charging chip;
FIG. 2 is a circuit diagram of a portion of the charging circuitry in a conventional switch charging chip;
FIG. 3 is a schematic diagram illustrating the conduction of a switching tube in a conventional switch charging chip;
fig. 4 is a block diagram of a charging circuit according to an embodiment of the present application;
fig. 5 is a circuit diagram of a charging circuit according to an embodiment of the present application;
fig. 6 is a block diagram of a switching tube in a charging circuit according to an embodiment of the present application;
fig. 7 is a schematic diagram illustrating the conduction of a switching tube in a charging circuit according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
At present, the charging circuit of the conventional switch charging chip may also be referred to as a switch charging unit, as shown in fig. 1, including a switch charging chip 100 and its peripheral circuits, wherein the switch charging chip 100 may be mainly divided into a charging main unit 101, a switching tube Q1 and a blocking tube driving.
Specifically, the input port of the switch charging unit is the supply voltage terminal VBUS of the switch charging chip 100, and the output port is the output voltage terminal Vsys. The switching tube Q1 is used for communicating the supply voltage terminal VBUS of the switching charging chip 100 with the charging main unit 101, and the communication port between the switching tube Q1 and the charging main unit 101 is generally referred to as PMID port. The blocking tube driving means may be also referred to as a driving means of the switching tube Q1 for controlling the switching tube Q1 to be turned on or off.
The circuit of the driving unit 201 of the switching transistor Q1 in the conventional switching chip charging circuit is shown in fig. 2. The driving unit 201 receives the voltage of the supply voltage terminal VBUS, and controls the on/off of the switching tube Q1 according to the voltage of the supply voltage terminal VBUS and the driving voltage Vcp.
Wherein the driving unit 201 includes:
and one end of the resistor R1 is connected with the power supply voltage end VBUS, wherein the other end of the resistor R1 is grounded through the zener diode Z1.
The first input terminal of the charge pump 202 is connected to the resistor R1, wherein the second input terminal of the charge pump 202 is connected to the supply voltage terminal VBUS.
It should be noted that the first input terminal of the charge pump 202 receives the power supply voltage VCC generated through the resistor R1.
And a third transistor N3 having a first end connected to the output end of the charge pump 202, wherein the third transistor N3 is an NMOS transistor, the control end of the third transistor N3 receives the enable signal ENN, and the second end is grounded.
The common terminal of the charge pump 202 and the third transistor N3 is used as an output port of the driving unit, and is used to connect to the control terminal of the switching transistor Q1 and output the driving voltage Vcp.
Since the second terminal of the switching tube Q1 is connected to the supply voltage terminal VBUS and the control terminal is connected to the output port of the driving unit 201, the on-off of the switching tube Q1 is controlled by the driving voltage Vcp of the driving circuit 201 and the voltage of the supply voltage terminal VBUS. When the voltage difference between the driving voltage Vcp and the power supply voltage terminal VBUS in the driving unit is greater than the on voltage of the switching tube Q1, the switching tube Q1 is in a conducting state, and at this time, the charging circuit has current passing through, and the switching charging chip is in a charging state. The drain electrode of the switch tube is a first end, the source electrode of the switch tube is a second end, and the grid electrode of the switch tube is a control end.
Because the port of the supply voltage terminal VBUS is a USB port, the charging circuit may perform hot plug of the port when charging, but the supply voltage terminal (i.e., the USB port) may generate positive and negative surges when hot plug.
When a negative surge occurs at the supply voltage end, referring to fig. 3, because the potential state of the control end of the switching tube Q1 is ground potential, when the voltage of the supply voltage end VBUS is-2V, the switching tube Q1 reaches an on voltage, the switching tube Q1 is turned on, and at this time, a current flows through the switching tube Q1, and the current flows in a direction from the first end to the second end of the switching tube, at this time, since the switching tube Q1 is in a turned-on state, the negative surge can propagate through the switching tube into a circuit connected with the switching tube, and generate negative surge damage to components in the circuit connected with the switching tube, thereby causing damage to the switching charging chip.
In view of the above problems, an embodiment of the present application provides a charging circuit, in which when a negative voltage occurs at a power supply voltage terminal, a switching tube in a switching charging chip is turned off, so that negative surges are prevented from propagating to a circuit connected with the switching tube through the switching tube, and damage to the switching charging chip caused by the negative surges generated at the power supply voltage terminal is avoided.
Referring to fig. 4, a charging circuit according to an embodiment of the present application includes:
a reference voltage selection unit 401, and a switch charging unit 402 connected to the reference voltage selection unit 401.
A reference voltage selecting unit 401 for selecting the lowest potential between the power supply voltage terminal and the ground terminal as a reference voltage, and outputting the reference voltage. The voltage of the grounding terminal is ground potential, namely 0V. The voltage of the power supply voltage terminal is a variable, and changes according to a change in the voltage value of the input power supply voltage terminal.
The switch charging unit 402 is configured to receive a reference voltage, and output a control signal according to a difference between a voltage of the supply voltage terminal and the reference voltage to control on-off of communication between the supply voltage terminal of the switch charging unit 402 and a charging main unit of the switch charging unit. And if the voltage of the power supply voltage end is equal to the reference voltage, the control signal controls the communication between the power supply voltage end and the charging main unit of the switch charging unit to be disconnected.
In this embodiment, when negative pressure occurs at the power supply voltage end, the lowest potential selected by the reference voltage selecting unit is the voltage of the power supply voltage end, and at this time, the voltage of the power supply voltage end is equal to the voltage of the reference voltage, so that the control signal controls the communication between the power supply voltage end in the switch charging unit and the charging main unit of the switch charging unit to be disconnected, thereby blocking the propagation of negative surge, and avoiding the damage to the switch charging chip caused by the negative pressure occurring at the power supply voltage end.
Alternatively, referring to fig. 5, in another embodiment of the present application, an implementation of the reference voltage selecting unit 501 includes:
a first transistor N1 and a second transistor N2, both NMOS transistors.
The control end of the first transistor N1 is connected to the ground, the first end receives the voltage of the supply voltage end VBUS, and the second end is connected to the second end of the second transistor N2.
The control terminal of the second transistor N2 receives the voltage of the supply voltage terminal VBUS, and the first terminal is connected to the ground terminal.
Wherein, the common terminal of the first transistor N1 and the second transistor N2 is used as the output port of the reference voltage selecting unit 501, and outputs the reference voltage prt_gnd.
It should be noted that, when the voltage of the supply voltage terminal VBUS is negative, the voltage of the control terminal of the first transistor N1 in the reference voltage selection unit 501 is 0V, the voltage of the second terminal is the voltage of the supply voltage terminal VBUS, and since a voltage difference exists between the control terminal and the second terminal of the first transistor N1, the first transistor N1 is in a conductive state, the voltage of the control terminal of the second transistor N2 is the negative voltage of the supply voltage terminal VBUS, the voltage of the first terminal is the voltage of the ground terminal, and the second transistor N2 is in a non-conductive state. At this time, the reference voltage selecting unit 501 selects the voltage of the supply voltage terminal VBUS as the reference voltage, and the reference voltage prt_gnd output by the reference selecting unit 501 is the voltage of the supply voltage terminal VBUS. The control end of the transistor is a grid electrode, the first end is a drain electrode, the second end is a source electrode, and the voltage of the grounding end is 0V.
When the voltage of the power supply voltage terminal is equal to 0V, the voltages of the control terminals of the first transistor N1 and the second transistor N2 in the reference selection unit 501 are both 0V, and the voltages of the first terminal are both 0V, so that the first transistor N1 and the second transistor N2 are both in a non-conductive state. Since neither the first transistor N1 nor the second transistor N2 is turned on, the reference voltage prt_gnd output from the common terminal of the first transistor N1 and the second transistor N2 is at the ground potential, i.e., 0V.
When the voltage of the supply voltage terminal VBUS is greater than 0V, the voltage of the control terminal of the second transistor N2 in the reference voltage selection unit 501 is the voltage of the supply voltage terminal greater than 0V, the voltage of the first terminal is the voltage of the ground terminal, and since there is a voltage difference between the control terminal and the first terminal of the second transistor N2, the second transistor N2 is in a conductive state, the voltage of the control terminal of the first transistor N1 is the voltage of the ground potential, and the first terminal is the voltage of the supply voltage terminal VBUS, so the first transistor N1 is in a non-conductive state. At this time, the reference voltage selecting unit 501 selects the voltage of the ground terminal as the reference voltage, and the reference voltage prt_gnd output by the reference selecting unit 501 is the voltage of the ground terminal. The control end of the transistor is a grid electrode, the first end is a drain electrode, the second end is a source electrode, and the voltage of the grounding end is 0V.
Optionally, in another embodiment of the present application, the switch charging unit is configured to control on-off of a switching tube disposed between the power supply voltage terminal and the charging main unit of the switch charging unit, so as to control on-off of communication between the power supply voltage terminal of the switch charging unit and the charging main unit of the switch charging unit.
In the switch charging unit, a switching tube is arranged between the power supply voltage end and the charging main unit of the switch charging unit, and the on-off of the communication between the power supply voltage end of the switch charging unit and the charging main unit of the switch charging unit can be controlled by controlling the on-off of the switching tube.
It should be noted that, in the switch charging unit in this embodiment, only when the negative voltage occurs at the power supply voltage end, the reference selecting unit outputs the reference voltage, so as to control the on-off of the switch tube in the switch charging unit. When the power supply voltage terminal is in normal operation, the on-off state of the middle switching tube of the switching charging unit and the working state of other components in the switching charging unit are not different from those of the charging circuit in the prior art, and the details are not repeated here.
In addition, in the switch charging unit, besides receiving the reference voltage output by the reference voltage selecting unit through the switch tube in the driving unit, the structure of other components is also equivalent to that of a charging circuit in the prior art, and the switch charging unit is basically also in the form of a switch charging chip.
Of course, the reference voltage selection unit described in this embodiment may also be integrated in the circuit board of the switch charging unit to form a switch charging chip; of course, it is also possible to provide a peripheral circuit for switching the charging chip.
Optionally, in another embodiment of the present application, a driving unit in the switch charging unit is connected to the reference voltage selecting unit, and is configured to receive the reference voltage, and control on/off of the switching tube according to a difference between the voltage of the power supply voltage terminal and the reference voltage.
It should be noted that, the on-off of the switching tube in the switching charging unit is controlled by the driving unit in the switching charging unit, the control end of the switching tube is connected with the output port of the driving unit, the second end of the switching tube is connected with the power supply voltage end, wherein the second end of the switching tube is a source electrode, and the control end is a grid electrode. When the gate-source voltage of the switching tube reaches the starting voltage, the switching tube is conducted.
Alternatively, in another embodiment of the present application, referring to fig. 5, the driving unit 502 includes:
and one end of the resistor R1 is connected with the power supply voltage end VBUS, wherein the other end of the resistor R1 is grounded through the zener diode Z1.
A charge pump 503 having a first input coupled to the resistor R1, wherein a second input of the charge pump 503 is coupled to the supply voltage terminal VBUS. And a third transistor N3 having a first terminal connected to the output terminal of the charge pump 503, wherein the third transistor N3 is an NMOS transistor, the control terminal of the third transistor N3 receives the enable signal ENN, and the second terminal receives the reference voltage prt_gnd.
The common terminal of the charge pump 503 and the third transistor N3 is used as an output port of the driving unit, and is used for connecting with a control terminal of the switching transistor.
It should be noted that, when the voltage of the supply voltage terminal VBUS is within a certain range, the charge pump 503 receives the voltage of the supply voltage terminal VBUS through the second input terminal of the charge pump 503, amplifies the voltage, and then outputs the charge pump output voltage Vcp through the output port of the charge pump 503. When the voltage of the supply voltage terminal VBUS is greater than a certain value, the zener diode Z1 is broken down reversely, and a current flows through the resistor R1, at this time, the first input terminal of the charge pump 503 receives the supply voltage Vcc flowing through the resistor R1, amplifies it, and then outputs the output voltage Vcp of the charge pump through the output port of the charge pump 503. When the first input port and the second output port of the charge pump 503 are set to be at different values for the voltages of the supply voltage terminal VBUS, the charge pump 503 can amplify the voltages of the supply voltage terminal VBUS according to the voltages of the different supply voltage terminals VBUS and output the output voltage Vcp of the charge pump, so as to maintain the normal operation of the charging circuit.
It should be further noted that the on/off state of the third transistor N3 is controlled by the enable signal ENN. If the switch charging unit 502 outputs a control signal to control the switching transistor Q1 to be in an off state, the enable signal ENN received by the control terminal of the third transistor N3 controls the third transistor N3 to be turned on, and at this time, the reference voltage prt_gnd is the voltage of the control terminal of the switching transistor Q1 through the third transistor N3. At this time, if the supply voltage terminal VBUS generates a negative voltage, the reference voltage prt_gnd selected by the reference voltage selecting unit is the voltage of the supply voltage terminal VBUS, and since the voltage of the control terminal of the switching tube Q1 is equal to the voltage of the source of the switching tube Q1, the switching tube Q1 is in a non-conductive state. If the switch charging unit 502 outputs a signal to control the switch Q1 to be in a conducting state, the enable signal ENN received by the control end of the third transistor N3 controls the third transistor N3 to be turned off, and the reference voltage prt_gnd cannot reach the control end of the switch Q1 through the third transistor N3, so that the reference voltage prt_gnd does not participate in or control the working states of the components in the switch charging unit 502.
Alternatively, in another embodiment of the present application, referring to fig. 6, a switching tube includes: transistor N4 with diode D1.
The diode D1 is configured to be broken down preferentially when the transistor N4 encounters a large current or a large voltage, and the transistor N4 is protected from being damaged by the large current or the large voltage by discharging the large current or the large voltage in advance, wherein the transistor N4 may be an NMOS transistor or a PMOS transistor.
Optionally, in another embodiment of the present application, a diode is further connected to the switching tube. The anode of the diode is connected with the second end of the switching tube, and the cathode of the diode is connected with the first end of the switching tube.
The first end of the switch tube is a drain electrode, and the second end is a source electrode. The diode is connected in parallel between the drain electrode and the source electrode of the switching tube and is used for being broken down preferentially when high current or high voltage appears at two ends of the switching tube, and the high current or the high voltage is leaked in advance so as to prevent the switching tube from being damaged by the high current or the high voltage. In this embodiment, the switching transistor may be a transistor, specifically, an NMOS transistor or a PMOS transistor.
In the charging circuit provided by the application, when the negative pressure occurs at the power supply voltage end, the lowest potential selected by the reference voltage selecting unit is the voltage of the power supply voltage end, and the voltage of the power supply voltage end is equal to the reference voltage, so that the control signal controls the switching-off of the switching tube in the switch charging unit to control the communication between the power supply voltage end and the charging main unit of the switch charging unit to be disconnected. Because the switching tube in the switch charging unit is disconnected, negative surge cannot propagate through the switching tube, and damage to the switch charging chip caused by the negative surge generated at the power supply voltage end is avoided.
Referring to fig. 7, when a negative voltage occurs at the supply voltage terminal, the reference voltage selecting unit selects the voltage of the supply voltage terminal VBUS as the reference voltage prt_gnd, and the third transistor is in the on state at this time, so that the voltage of the supply voltage terminal VBUS for controlling the on/off of the switching transistor Q1 is equal to the reference voltage prt_gnd, and the switching transistor Q1 is in the off state. Comparing fig. 3 and fig. 7, it can be known that when the negative pressure occurs at the supply voltage terminal VBUS, if the charging chip is provided with the reference selection unit, the switching tube Q1 is in the off state, no current passes through the switching tube Q1, and the negative surge cannot be propagated to the inside of the switching charging chip, so that the damage to the switching charging chip due to the negative pressure occurring at the supply voltage terminal is avoided.
The embodiment of the application discloses an electronic device, which comprises a charging circuit, wherein the charging circuit comprises: the switching charging device comprises a reference voltage selection unit and a switch charging unit connected with the reference voltage selection unit; wherein:
the reference voltage selecting unit is used for selecting the lowest potential between a power supply voltage terminal and a grounding terminal as a reference voltage and outputting the reference voltage.
The switch charging unit is used for receiving the reference voltage and outputting a control signal to control the on-off of the communication between the power supply voltage end of the switch charging unit and the charging main unit of the switch charging unit according to the difference value between the voltage of the power supply voltage end and the reference voltage; and if the voltage of the power supply voltage end is equal to the reference voltage, the control signal controls the communication between the power supply voltage end and the charging main unit of the switch charging unit to be disconnected.
Optionally, in another embodiment of the present application, the reference voltage selecting unit includes:
a first transistor and a second transistor, both of which are NMOS transistors.
The control end of the first transistor is connected with the grounding end, the first end receives the voltage of the power supply voltage end, and the second end of the first transistor is connected with the second end of the second transistor.
The control end of the second transistor receives the voltage of the power supply voltage end, and the first end of the second transistor is connected with the grounding end. And the common terminal of the first transistor and the second transistor is used as an output port of the reference selection unit to output the reference voltage.
Optionally, in another embodiment of the present application, the switch charging unit is configured to control on-off of a switching tube disposed between the power supply voltage end and the charging main unit of the switch charging unit, so as to control on-off of communication between the power supply voltage end of the switch charging unit and the charging main unit of the switch charging unit.
Optionally, in another embodiment of the present application, a driving unit in the switch charging unit is connected to the reference voltage selecting unit, and is configured to receive the reference voltage, and control on-off of the switching tube according to a difference between the voltage of the power supply voltage terminal and the reference voltage.
Optionally, in another embodiment of the present application, the driving unit includes:
and one end of the resistor is connected with the power supply voltage end, and the other end of the resistor is grounded through a voltage stabilizing diode.
The first input end of the charge pump is connected with the resistor, and the second input end of the charge pump is connected with the power supply voltage end; and a third transistor with a first end connected with the output end of the charge pump, wherein the third transistor is an NMOS transistor, a control end of the third transistor receives an enabling signal, and a second end receives the reference voltage.
And the common end of the charge pump and the third transistor is used as an output port of the driving unit and is used for connecting the control end of the switching tube.
Optionally, in another embodiment of the present application, if the switch charging unit outputs a control signal to control the switch transistor to be in an off state, the enable signal received by the control end of the third transistor controls the third transistor to be turned on.
Optionally, in another embodiment of the present application, the switching tube includes: a transistor with a diode.
Optionally, in another embodiment of the present application, a diode is further connected to the switching tube; the positive electrode of the diode is connected with the second end of the switching tube, and the negative electrode of the diode is connected with the first end of the switching tube.
It should be noted that, in the electronic device disclosed in the above embodiments of the present application, the specific structure and the working process of the charging circuit can be referred to the content of the corresponding embodiment of the charging circuit, which is not described herein again.
In particular implementations, the electronic device may include, but is not limited to, a cell phone, tablet, other universal serial bus (Universal Serial Bus, USB) interface device, etc.
Those skilled in the art will be able to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
It is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Claims (7)
1. A charging circuit, comprising:
the switching charging device comprises a reference voltage selection unit and a switch charging unit connected with the reference voltage selection unit; wherein:
the reference voltage selecting unit is used for selecting the lowest potential between a power supply voltage end and a grounding end as a reference voltage and outputting the reference voltage;
the switch charging unit is used for receiving the reference voltage and outputting a control signal to control the on-off of a switching tube between the power supply voltage end of the switch charging unit and a charging main unit of the switch charging unit according to the difference value between the voltage of the power supply voltage end and the reference voltage; if the voltage of the power supply voltage end is equal to the reference voltage, the control signal controls the communication between the power supply voltage end and the charging main unit of the switch charging unit to be disconnected;
wherein the reference voltage selecting unit includes:
a first transistor and a second transistor which are NMOS transistors;
the control end of the first transistor is connected with the grounding end, the first end receives the voltage of the power supply voltage end, and the second end of the first transistor is connected with the second end of the second transistor;
the control end of the second transistor receives the voltage of the power supply voltage end, and the first end of the second transistor is connected with the grounding end;
and the common terminal of the first transistor and the second transistor is used as an output port of the reference voltage selection unit to output the reference voltage.
2. The charging circuit according to claim 1, wherein the driving unit in the switch charging unit is connected to the reference voltage selecting unit, and is configured to receive the reference voltage, and control on/off of the switching tube according to a difference between the voltage of the power supply voltage terminal and the reference voltage.
3. The charging circuit of claim 2, wherein the driving unit comprises:
one end of the resistor is connected with the power supply voltage end, and the other end of the resistor is grounded through a voltage stabilizing diode;
the first input end of the charge pump is connected with the resistor, and the second input end of the charge pump is connected with the power supply voltage end; a third transistor with a first end connected with the output end of the charge pump, wherein the third transistor is an NMOS transistor, a control end of the third transistor receives an enabling signal, and a second end receives the reference voltage;
and the common end of the charge pump and the third transistor is used as an output port of the driving unit and is used for connecting the control end of the switching tube.
4. A charging circuit according to claim 3, wherein if the switch charging unit outputs a control signal to control the switch transistor to be in an off state, the enable signal received by the control terminal of the third transistor controls the third transistor to be turned on.
5. A charging circuit according to claim 3, wherein the switching tube comprises:
a transistor with a diode.
6. A charging circuit according to claim 3, wherein the switching tube is further connected to a diode; the positive electrode of the diode is connected with the second end of the switching tube, and the negative electrode of the diode is connected with the first end of the switching tube.
7. An electronic device, comprising: a charging circuit as claimed in any one of claims 1 to 6.
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| CN201811577424.9A CN109638917B (en) | 2018-12-20 | 2018-12-20 | Charging circuit and electronic equipment |
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| CN201811577424.9A CN109638917B (en) | 2018-12-20 | 2018-12-20 | Charging circuit and electronic equipment |
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| CN116455006B (en) * | 2022-01-07 | 2024-04-05 | 荣耀终端有限公司 | Charging circuit, electronic equipment and charging system |
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| CN109638917A (en) | 2019-04-16 |
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