Charging circuit and electronic equipment

Abstract

The utility model relates to the technical field of circuits, in particular to a charging circuit and electronic equipment. The charging circuit comprises a power supply receiving module and a switch module, the switch module comprises at least one switch tube, the power supply receiving module comprises a low dropout linear regulator, and the low dropout linear regulator comprises a voltage feedback unit; wherein the input end of the power supply receiving module is connected with the first end of the switch module, the output end of the power supply receiving module is respectively connected with the second end of the switch module and the input end of the voltage feedback unit, and the output end of the voltage feedback unit is connected with the control end of the switch module. According to the scheme, the charging efficiency of the charging circuit can be improved, and the charging time is shortened.

Description

Technical Field

[0001] The utility model relates to the technical field of current detection, in particular to a charging circuit and electronic equipment. Background Art

[0002] In the related art, a low dropout regulator (LDO) is provided in the charging circuit to provide a stable DC voltage. However, the LDO uses a P-type switching tube as a regulating tube to control the working state of the LDO. Due to the high impedance of the P-type switching tube, the LDO efficiency is low, resulting in low charging efficiency of the charging circuit and a long charging time. Utility Model Content

[0003] The utility model provides a charging circuit and an electronic device, the main purpose of which is to improve the charging efficiency of the charging circuit and reduce the charging time.

[0004] According to one aspect of the present invention, a charging circuit is provided, comprising: a power receiving module, a switch module, wherein the switch module comprises at least one switch tube, the power receiving module comprises a low voltage dropout linear regulator, and the low voltage dropout linear regulator comprises a voltage feedback unit; wherein,

[0005] The input end of the power receiving module is connected to the first end of the switch module, the output end of the power receiving module is connected to the second end of the switch module and the input end of the voltage feedback unit respectively, and the output end of the voltage feedback unit is connected to the control end of the switch module;

[0006] Optionally, in one embodiment of the present invention, when the input end of the power receiving module receives an input voltage, the switch tube is in the on state, the switch module is in the on state, and the voltage feedback unit performs negative feedback control on the first output voltage corresponding to the second end of the switch module.

[0007] Optionally, in one embodiment of the present invention, the charging circuit further includes a voltage conversion module; wherein,

[0008] The first end of the voltage conversion module is respectively connected to the input end of the power receiving module and the first end of the switch module, the second end of the voltage conversion module is respectively connected to the output end of the voltage feedback unit and the control end of the switch module, and the third end of the voltage conversion module is respectively connected to the output end of the power receiving module, the second end of the switch module, and the input end of the voltage feedback unit;

[0009] In the case that the input voltage is received at the first end of the voltage conversion module, the second end of the voltage conversion module outputs a control signal to the control end of the switch module, so that the switch tube is in a conducting state, and the switch module is in a conducting state.

[0010] Optionally, in an embodiment of the utility model, the voltage conversion module carries out voltage conversion to the first output voltage, obtains and outputs second output voltage.

[0011] Optionally, in an embodiment of the utility model, the voltage conversion module includes charge pump circuit;Among them,

[0012] The input end of the charge pump circuit is the third end of the voltage conversion module, and the charge pump circuit is used for voltage conversion to the first output voltage, obtains and outputs second output voltage.

[0013] Optionally, in an embodiment of the utility model, the voltage feedback unit includes error amplifier, first resistance and second resistance;Among them,

[0014] The first end of the first resistance is connected with the output end of the power receiving module and the second end of the switch module respectively, the second end of the first resistance is connected with the first end of the second resistance and the first input end of the error amplifier respectively, the second input end of the error amplifier receives reference voltage, the output end of the error amplifier is connected with the control end of the switch module, and the second end of the second resistance is grounded.

[0015] Optionally, in an embodiment of the utility model, the switch module includes first N type switch tube and second N type switch tube;Among them,

[0016] The drain of the first N type switch tube is the first end of the switch module, the source of the first N type switch tube is connected with the source of the second N type switch tube, the drain of the second N type switch tube is the second end of the switch module, and the connection point between the gate of the first N type switch tube and the gate of the second N type switch tube is the control end of the switch module.

[0017] Optionally, in an embodiment of the utility model, the charging circuit further includes a capacitor;Among them,

[0018] The first end of the capacitor is connected with the output end of the power receiving module, the second end of the switch module and the input end of the voltage feedback unit respectively, and the second end of the capacitor is grounded.

[0019] Optionally, in an embodiment of the utility model, the power receiving module is a wireless power receiving module.

[0020] Optionally, in one embodiment of the present invention, the switch module is an overvoltage protection switch module.

[0021] According to another aspect of the present invention, an electronic device is provided, comprising: a charging circuit as described in any one of the aforementioned aspects.

[0022] In summary, the charging circuit and electronic device provided by the embodiments of the present invention use the switching tube in the switching module to replace the adjustment tube in the LDO to control the working state of the LDO, thereby improving the low efficiency of the LDO due to the high impedance of the adjustment tube in the LDO, improving the charging efficiency of the charging circuit, and reducing the charging time.

[0023] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and are not restrictive of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention, and together with the description, serve to explain the principles of the present invention.

[0025] Figure 1 A schematic structural diagram of a wireless charging circuit in a related art provided by an embodiment of the present utility model;

[0026] Figure 2 This is a structural diagram of a charging circuit provided by an embodiment of the utility model.

[0027] Explanation of the reference numerals: power receiving module 1, switch module 2, voltage conversion module 3, voltage feedback unit 11, error amplifier U1, first resistor R1, second resistor R2, first N-type switch tube Q1, second N-type switch tube Q2, capacitor C1. DETAILED DESCRIPTION

[0028] Some embodiments of the present invention will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. Various changes, modifications and equivalents of the structures described herein will become apparent after understanding the present invention. For example, the connection relationships of the structures described herein are merely examples and are not limited to those connection relationships set forth herein, but can be changed as becomes apparent after understanding the present invention, except for connections that must be made in specific connection relationships. In addition, for the purpose of improving clarity and brevity, descriptions of features known in the art may be omitted.

[0029] The embodiments described in the following embodiments of the present invention do not represent all embodiments consistent with the present invention. Instead, they are merely examples of structures consistent with some aspects of the present invention as detailed in the appended claims.

[0030] It should be noted that a charging circuit, such as a wireless charging circuit, is internally provided with an LDO to provide a stable DC voltage. Figure 1 This is a schematic diagram of the structure of a wireless charging circuit in a related technology provided by an embodiment of the present utility model. Figure 1 As shown, the wireless charging circuit includes a wireless charging receiving chip RX, an overvoltage protection switch OVP and a charge pump chip CP. The LDO inside the wireless charging receiving chip RX includes an adjustment tube Q0, an error amplifier U1, a first resistor R1 and a second resistor R2; wherein,

[0031] The wireless charging receiver chip RX senses the wireless magnetic field generated by the charger and converts it into electrical energy for charging. Upon detecting voltage at its input terminal, Vrect, the wireless charging receiver chip RX turns on the adjustment transistor Q0, activating the internal LDO of the wireless charging receiver chip RX. The output terminal of the wireless charging receiver chip RX then outputs the output voltage VOUT. Upon detecting voltage at the WPCSNS pin, the charge pump chip CP uses internal circuitry to output a control voltage at the WPCGATE pin, which in turn turns on the first and second N-type switches Q1 and Q2 within the overvoltage protection switch (OVP), thereby activating the charge pump chip CP.

[0032] During operation, the LDO within the wireless charging receiver chip RX forms a negative feedback loop with the regulator transistor Q0, error amplifier U1, first resistor R1, and second resistor R2. Furthermore, since the regulator transistor Q0 is a P-type metal-oxide-semiconductor field-effect transistor (MOSFET) and operates in the constant current region (saturation region), the MOSFET characteristic curve shows that as the gate-source voltage Vgs of the regulator transistor Q0 increases, the continuous leakage current Id of the regulator transistor Q0 also increases. Within this region, changes in the drain-source voltage Vds of the regulator transistor Q0 do not cause changes in Id.

[0033] Therefore, when the input voltage at the input terminal Vrect of the wireless charging receiver chip RX remains unchanged and the output voltage VOUT of the LDO increases, the first resistor R1 and the second resistor R2 detect the change in output voltage VOUT, causing the feedback voltage VFB to also increase. The increased feedback voltage VFB is transmitted to the non-inverting terminal of the error amplifier U1 and compared with the reference voltage Vref received by the inverting terminal of the error amplifier U1 to generate a voltage difference. The error amplifier U1 then amplifies this voltage difference, thereby reducing the gate voltage Vg input to the adjustment tube Q0. This also reduces the continuous leakage current Id of the adjustment tube Q0, thereby reducing the output voltage of the LDO and suppressing the upward trend of the output voltage. When the output voltage VOUT of the LDO decreases, the negative feedback loop will increase the gate voltage Vg of the adjustment tube Q0, increasing the output current. The LDO output voltage will also increase, suppressing its downward trend.

[0034] However, since the adjustment tube Q0 is a PMOS, its impedance is relatively high. Therefore, for certain occasions requiring high current and low voltage difference, the adjustment tube Q0 has high loss, resulting in low LDO efficiency, which in turn leads to low charging efficiency and long charging time.

[0035] The present invention will be described in detail below with reference to specific embodiments.

[0036] Figure 2 This is a schematic diagram of the structure of a charging circuit provided by an embodiment of the present utility model. Figure 2 As shown, the charging circuit includes: a power receiving module 1, a switch module 2, the switch module 2 includes at least one switch tube, the power receiving module 1 includes a low voltage dropout linear regulator, and the low voltage dropout linear regulator includes a voltage feedback unit 11; wherein,

[0037] The input end Vrect of the power receiving module 1 is connected to the first end of the switch module 2, the output end Vout of the power receiving module 1 is respectively connected to the second end of the switch module 2 and the input end of the voltage feedback unit 11, and the output end of the voltage feedback unit 11 is connected to the control end of the switch module 2.

[0038] According to some embodiments, when the input terminal Vrect of the power receiving module 1 receives the input voltage Vin, at least one switch tube in the switch module 2 is in the on state, so that the switch module 2 is in the on state, and the voltage feedback unit 11 performs negative feedback control on the first output voltage Vout1 corresponding to the second end of the switch module 2.

[0039] In some embodiments, the switch tube in the switch module 2 is used to replace the adjusting tube in the LDO and the voltage feedback unit 11 in the low dropout linear regulator to form a negative feedback loop, which can improve the low efficiency of the LDO due to the high impedance of the adjusting tube in the LDO, improve the charging efficiency of the charging circuit, and reduce the charging time.

[0040] Optionally, in an embodiment of the utility model, as shown in Figure 2 the charging circuit further includes a voltage conversion module 3; wherein,

[0041] The first end WPCSNS of the voltage conversion module 3 is connected with the input end Vrect of the power receiving module 1 and the first end of the switch module 2 respectively, the second end WPCGATE of the voltage conversion module 3 is connected with the output end of the voltage feedback unit 11 and the control end of the switch module 2 respectively, and the third end VBUS of the voltage conversion module 3 is connected with the output end Vout of the power receiving module 1, the second end of the switch module 2 and the input end of the voltage feedback unit 11 respectively.

[0042] According to some embodiments, in the case that the first end WPCSNS of the voltage conversion module 3 receives the input voltage Vin, the second end WPCGATE of the voltage conversion module 3 outputs a control signal to the control end of the switch module 2, so that at least one switch tube in the switch module 2 is in a conducting state, so that the switch module 2 is in a conducting state. Therefore, the voltage conversion module in the charging circuit can be reused to control the switch module 2, and an additional control circuit is not needed to control the switch module 2, which can reduce the cost of the charging circuit.

[0043] In some embodiments, the voltage conversion module 3 can be used to convert the first output voltage Vout1 to obtain and output the second output voltage Vout2.

[0044] According to some embodiments, the voltage conversion module 3 can be a charger pump (CP) for example, which includes a charge pump circuit; wherein,

[0045] The input end of the charge pump circuit is the third end VBUS of the voltage conversion module 3, and the charge pump circuit is used to convert the first output voltage Vout1 to obtain and output the second output voltage Vout2.

[0046] Optionally, in an embodiment of the utility model, as shown in Figure 2 the voltage feedback unit includes an error amplifier U1, a first resistor R1 and a second resistor R2; wherein,

[0047] The first end of the first resistor R1 is respectively connected to the output end of the power receiving module 1 and the second end of the switch module 2, the second end of the first resistor R1 is respectively connected to the first end of the second resistor R2 and the first input end of the error amplifier U1, the second input end of the error amplifier U1 receives the reference voltage Vref, the output end of the error amplifier U1 is connected to the control end of the switch module 2, and the second end of the second resistor R2 is grounded.

[0048] According to some embodiments, the error amplifier U1, the first resistor R1, and the second resistor R2 can form a negative feedback loop with the switch tube in the switch module 2, wherein the error amplifier U1 compares the feedback voltage VFB collected by the first resistor R1 and the second resistor R2 with the reference voltage Vref and amplifies it, and inputs the amplified control voltage to the control end of the switch module 2.

[0049] Therefore, when the input voltage Vin remains unchanged and the first output voltage Vout1 increases, the first resistor R1 and the second resistor R2 detect the change in the first output voltage Vout1, causing the feedback voltage VFB to also increase, resulting in a decrease in the control voltage input from the error amplifier U1 to the switch module 2. Since the continuous leakage current Id of the switch tube in the switch module 2 is related to the control voltage, when the control voltage decreases, the continuous leakage current Id of the switch tube in the switch module 2 also decreases, thereby reducing the first output voltage Vout1 and suppressing its upward trend. When the input voltage Vin remains unchanged and the first output voltage Vout1 decreases, the negative feedback loop will increase the control voltage, increasing the continuous leakage current Id of the switch tube in the switch module 2, causing the first output voltage Vout1 to increase, suppressing its downward trend.

[0050] Optionally, in one embodiment of the present invention, Figure 2 As shown, the switch module 2 includes a first N-type switch tube Q1 and a second N-type switch tube Q2; wherein,

[0051] The drain of the first N-type switch tube Q1 is the first end of the switch module 2, the source of the first N-type switch tube Q1 is connected to the source of the second N-type switch tube Q2, the drain of the second N-type switch tube Q2 is the second end of the switch module 2, and the connection point between the gate of the first N-type switch tube Q1 and the gate of the second N-type switch tube Q2 is the control end of the switch module.

[0052] According to some embodiments, the first N-type switch transistor Q1 and the second N-type switch transistor Q2 may be, for example, NMOS.

[0053] In some embodiments, as can be seen from the MOS characteristic curve, as the gate-source voltage Vgs of the first N-type switch Q1 and the second N-type switch Q2 increases, the continuous leakage current Id of the first N-type switch Q1 and the second N-type switch Q2 also increases accordingly. Within this range, changes in the drain-source voltage Vds of the first N-type switch Q1 and the second N-type switch Q2 do not cause changes in their continuous leakage current Id.

[0054] Therefore, because the error amplifier U1 inputs the control voltage to the gates of the first N-type switch Q1 and the second N-type switch Q2, when the input voltage Vin remains unchanged and the first output voltage Vout1 increases, the control voltage decreases, the gate voltage of the first N-type switch Q1 and the second N-type switch Q2 decreases, and the gate-source voltage Vgs of the first N-type switch Q1 and the second N-type switch Q2 decreases. Consequently, the continuous leakage current Id of the first N-type switch Q1 and the second N-type switch Q2 also decreases, thereby reducing the first output voltage Vout1 and suppressing its upward trend. When the input voltage Vin remains unchanged and the first output voltage Vout1 decreases, the negative feedback loop will increase the control voltage, increase the gate-source voltage Vgs of the first N-type switch Q1 and the second N-type switch Q2, and increase the continuous leakage current Id of the first N-type switch Q1 and the second N-type switch Q2. This will increase the first output voltage Vout1 and suppress its downward trend.

[0055] In some embodiments, the N-type switches in switch module 2 are connected back-to-back, thereby improving the safety of switch module 2 during use. Furthermore, because the impedance of the N-type switch is lower than that of the P-type switch, the higher the continuous leakage current Id, the lower the loss of the N-type switch relative to the P-type switch. This further improves the charging efficiency of the charging circuit, reduces charging time, enables high-power charging, and enhances the user experience. Furthermore, because the impedance of the N-type switch is lower than that of the P-type switch, the N-type switch exhibits a lower impedance.

[0056] Optionally, in one embodiment of the present invention, Figure 2 As shown, the switch module 2 also includes a first diode D1 and a second diode D2; wherein, the anode of the first diode D1 is connected to the source of the first N-type switch tube Q1, the cathode of the first diode D1 is connected to the drain of the first N-type switch tube Q1, the anode of the second diode D2 is connected to the source of the second N-type switch tube Q2, and the cathode of the second diode D2 is connected to the drain of the second N-type switch tube Q2.

[0057] In some embodiments, the first diode D1 and the second diode D2 are used to improve the reliability and stability of the switch module 2 .

[0058] Optionally, in one embodiment of the present invention, the switch module 2 may be an overvoltage protection (OVP) switch module. Therefore, the OVP switch module in the charging circuit can be reused to replace the pass transistor in the LDO, eliminating the need for an additional switch transistor and reducing the cost of the charging circuit.

[0059] According to some embodiments, an OVP switch module is a switch module with a protection function. When the voltage input to the OVP switch module is lower than the protection voltage threshold, the OVP switch module is in the on state; conversely, when the voltage input to the OVP switch module is not lower than the protection voltage threshold, the OVP switch module is in the off state. This can improve the safety of electronic devices during use.

[0060] In some embodiments, the protection voltage threshold does not specifically refer to a fixed threshold, and the protection voltage threshold can be adjusted according to actual application scenarios.

[0061] Optionally, in one embodiment of the present invention, Figure 2 As shown, the charging circuit also includes a capacitor C1; wherein,

[0062] A first end of the capacitor C1 is respectively connected to the output end Vout of the power receiving module 1 , the second end of the switch module 2 , and the input end of the voltage feedback unit 11 , and a second end of the capacitor C1 is grounded.

[0063] According to some embodiments, the first terminal of the capacitor C1 may also be connected to the third terminal VBUS of the voltage conversion module 3 .

[0064] In some embodiments, the capacitor C1 is used to filter out the AC component in the input voltage Vin, thereby reducing the ripple of the input voltage Vin.

[0065] Optionally, in an embodiment of the present invention, the power receiving module 1 may be a wireless power receiving module, for example, which may be a wireless charging receiving chip RX.

[0066] In summary, the charging circuit provided by the embodiment of the present invention uses the switching tube in the switching module to replace the adjustment tube in the LDO to control the working state of the LDO, which can improve the low efficiency of the LDO due to the high impedance of the adjustment tube in the LDO. It can also improve the charging efficiency of the charging circuit, shorten the charging time, achieve high-power charging, and improve the user experience.

[0067] According to an embodiment of the present invention, the present invention further provides an electronic device.

[0068] The electronic device includes: a charging circuit as shown in any of the above embodiments.

[0069] In summary, the electronic device provided by the embodiment of the present invention can improve charging efficiency, reduce charging time, achieve high-power charging, and improve user experience by using the above-mentioned charging circuit.

[0070] Furthermore, the word "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as advantageous over other aspects or designs. Rather, the use of the word exemplary is intended to present concepts in a concrete manner. As used herein, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." That is, unless otherwise specified or clear from the context, "X applies to A or B" is intended to mean any of the natural inclusive permutations. That is, if X applies to A; X applies to B; or X applies to both A and B, then "X applies to A or B" satisfies any of the aforementioned instances. Furthermore, the articles "a" and "an," as used in this application and the appended claims, are generally understood to mean "one or more," unless otherwise specified or clear from the context to refer to the singular form.

[0071] Similarly, although the present invention has been shown and described with respect to one or more implementations, after reading and understanding the specification and drawings, those skilled in the art will think of equivalent variations and modifications. The present invention includes all such modifications and variations and is limited only by the scope of the claims. In particular, with respect to the various functions performed by the components described above (e.g., elements, resources, etc.), unless otherwise indicated, the terms used to describe such components are intended to correspond to any component (functionally equivalent) that performs the specific functions of the described components, even if structurally not equivalent to the structure of the invention. In addition, although the specific features of the present invention may have been described with respect to only one of several implementations, such features may be combined with one or more other features of other implementations as may be desired and beneficial to any given or specific application. In addition, with respect to the "including", "having", "having", "having", or variations thereof used in the specific embodiments or claims, such terms are intended to be inclusive in a manner similar to the term "comprising".

[0072] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing the invention herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present invention being indicated by the following claims.

[0073] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A charging circuit, characterized in that: include: A power receiving module and a switch module, wherein the switch module includes at least one switch tube, the power receiving module includes a low voltage dropout linear regulator, and the low voltage dropout linear regulator includes a voltage feedback unit; wherein, The input end of the power receiving module is connected to the first end of the switch module, the output end of the power receiving module is connected to the second end of the switch module and the input end of the voltage feedback unit respectively, and the output end of the voltage feedback unit is connected to the control end of the switch module; The switch module includes a first N-type switch tube and a second N-type switch tube; the drain of the first N-type switch tube is the first end of the switch module, the source of the first N-type switch tube is connected to the source of the second N-type switch tube, the drain of the second N-type switch tube is the second end of the switch module, and the connection point between the gate of the first N-type switch tube and the gate of the second N-type switch tube is the control end of the switch module.

2. The charging circuit according to claim 1, wherein: When the input end of the power receiving module receives an input voltage, the switch tube is in the on state, the switch module is in the on state, and the voltage feedback unit performs negative feedback control on the first output voltage corresponding to the second end of the switch module.

3. The charging circuit according to claim 2, wherein: The charging circuit also includes a voltage conversion module; wherein, The first end of the voltage conversion module is respectively connected to the input end of the power receiving module and the first end of the switch module, the second end of the voltage conversion module is respectively connected to the output end of the voltage feedback unit and the control end of the switch module, and the third end of the voltage conversion module is respectively connected to the output end of the power receiving module, the second end of the switch module, and the input end of the voltage feedback unit; When the first end of the voltage conversion module receives an input voltage, the second end of the voltage conversion module outputs a control signal to the control end of the switch module to turn on the switch tube.

4. The charging circuit according to claim 3, wherein: The voltage conversion module performs voltage conversion on the first output voltage to obtain and output a second output voltage.

5. The charging circuit according to claim 4, characterized in that: The voltage conversion module includes a charge pump circuit; wherein, The input end of the charge pump circuit is the third end of the voltage conversion module. The charge pump circuit is used to perform voltage conversion on the first output voltage to obtain and output a second output voltage.

6. The charging circuit according to claim 1, wherein: The voltage feedback unit includes an error amplifier, a first resistor and a second resistor; wherein, The first end of the first resistor is respectively connected to the output end of the power receiving module and the second end of the switch module, the second end of the first resistor is respectively connected to the first end of the second resistor and the first input end of the error amplifier, the second input end of the error amplifier receives a reference voltage, the output end of the error amplifier is connected to the control end of the switch module, and the second end of the second resistor is grounded.

7. The charging circuit according to claim 1, wherein: The charging circuit also includes a capacitor; wherein, The first end of the capacitor is respectively connected to the output end of the power receiving module, the second end of the switch module and the input end of the voltage feedback unit, and the second end of the capacitor is grounded.

8. The charging circuit according to claim 1, wherein: The power receiving module is a wireless power receiving module.

9. An electronic device, characterized in that: include: The charging circuit according to any one of claims 1 to 8.

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