Charging circuit and charging control method

Abstract

A charging circuit and a charging control method. The charging circuit includes a power stage circuit to operate at least one power switch according to an operation signal to convert an input power source into a charging power source to charge a battery; a control circuit coupled with the power stage circuit to generate the operation signal according to a current feedback signal and a voltage feedback signal; a voltage feedback circuit to compare a voltage sense signal related to a charging voltage of the charging power source with a voltage reference level to generate the voltage feedback signal; a battery core voltage drop sensing circuit coupled with a battery core of the battery to sense a battery core voltage drop of the battery core to generate a core voltage drop sense signal; and an adjustment circuit coupled with the battery core voltage drop sensing circuit to generate an adjustment signal according to the core voltage drop sense signal to adaptively adjust the voltage reference level.

Description

Technical Field

[0001] This invention relates to charging circuits, and more particularly to a charging circuit and charging control method that shortens charging time by adaptively adjusting the voltage reference level. Background Technology

[0002] Please see Figure 1A The diagram shows a schematic of a known charging circuit. This known charging circuit 10 includes a control circuit 11, a power stage circuit 12, and a feedback circuit 13. The power stage circuit 12 operates power switches QA and QB according to operation signals UG and LG to control the conduction state of inductor L, thereby converting the input power supply Vin into a charging power supply Vch to charge battery 19. The charging power supply Vch corresponds to the charging voltage Vbat and the charging current Ibat. The control circuit 11 is coupled to the power stage circuit 12 and generates operation signals UG and LG according to the feedback signal FB.

[0003] Feedback circuit 13 generates feedback signal FB based on charging current Ibat and charging voltage Vbat. Power stage circuit 12 includes power switches QA and QB and inductor L. Power switch QA is coupled between the input power supply Vin and the first terminal LX1 of inductor L, while power switch QB is coupled between ground potential GND and the first terminal LX1 of inductor L. Operating signals UG and LG are used to control power switches QA and QB, respectively, to switch the first terminal LX1 of inductor L between the input power supply Vin and the ground potential GND. Charging power supply Vch is coupled to the second terminal LX2 of inductor L, thereby converting the input power supply Vin into the charging power supply Vch to charge battery 19.

[0004] Figure 1B It displays the charging voltage Vbat of a known charging circuit (e.g., Figure 1B (as indicated by the thick black solid line) and charging current Ibat (e.g.) Figure 1B A schematic diagram illustrating the relationship between the characteristic curve (shown by the thick black dashed line) and time. (See diagram below.) Figure 1B As shown, in this known charging circuit 10, from time point t0 to the period before time point t1, the charging current Ibat is adjusted to a fixed current Ict to charge the battery 19; from time point t1 to the period after time point t2, the charging voltage Vbat is adjusted to a fixed voltage Vct to charge the battery 19.

[0005] During the later stage of charging, when the charging voltage Vbat is adjusted to a fixed voltage Vct, the charging current Ibat continues to charge the battery cell 191 inside the battery 19. Because the charging voltage Vbat is adjusted to a fixed voltage Vct, as the voltage of the battery cell 191 gradually increases, the voltage drop across the resistor Rpr (containing chemical resistance) within the battery 19 gradually decreases, causing the charging current Ibat to gradually decrease. When the charging current Ibat decreases to a near-zero charging current Ibf, it indicates that the battery 19 is fully charged. During the later stage from time point t1 to time point t2, the charging efficiency is lower due to the gradual decrease in the charging current Ibat. The longer this period of lower charging efficiency lasts, the longer the charging time. Summary of the Invention

[0006] In one viewpoint, the present invention provides a charging circuit comprising: a power stage circuit for operating at least one power switch therein according to an operation signal to convert an input power supply into a charging power supply for charging a battery, wherein the charging power supply includes a charging voltage and a charging current; a control circuit coupled to the power stage circuit for generating the operation signal according to a current feedback signal and a voltage feedback signal; a current feedback circuit for generating the current feedback signal by comparing a current sensing signal related to the charging current with a current reference level; a voltage feedback circuit for generating the voltage feedback signal by comparing a voltage sensing signal related to the charging voltage with a voltage reference level; a battery cell voltage drop sensing circuit coupled to a battery cell for sensing a cell voltage drop of the battery cell and generating a cell voltage drop sensing signal; and an adjustment circuit coupled to the battery cell voltage drop sensing circuit for generating an adjustment signal according to the cell voltage drop sensing signal to adaptively adjust the voltage reference level.

[0007] In another viewpoint, the present invention provides a charging control method for converting an input power supply into a charging power supply to charge a battery. The charging control method includes: operating at least one power switch according to an operation signal to convert the input power supply into the charging power supply, wherein the charging power supply includes a charging voltage and a charging current; generating the operation signal according to a current feedback signal and a voltage feedback signal; comparing a current sensing signal related to the charging current with a current reference level to generate the current feedback signal; comparing a voltage sensing signal related to the charging voltage with a voltage reference level to generate the voltage feedback signal; and a reference level adjustment step, including: sensing a cell voltage drop inside the battery to generate a cell voltage drop sensing signal; and generating an adjustment signal based on the cell voltage drop sensing signal to adaptively adjust the voltage reference level.

[0008] In one embodiment, the adjustment circuit adaptively lowers the voltage reference level when the core voltage drop sensing signal exceeds a preset threshold.

[0009] In one embodiment, the adjustment circuit includes a step-down circuit for adjusting the step-down signal to an enable level when the core voltage drop sensing signal exceeds the preset threshold, indicating that the core voltage drop sensing signal exceeds the preset threshold, and lowering the voltage reference level by a preset difference.

[0010] In one embodiment, the charging circuit further includes a timing circuit coupled to the adjustment circuit, and timing a timeout period based on the step signal at a prohibition level indicating that the core voltage drop sensing signal does not exceed the preset threshold. At an end point of the timeout period and when the step signal is at the prohibition level, the timing circuit generates a stop adjustment signal to end the adaptive adjustment of the voltage reference level.

[0011] In one embodiment, the control circuit generates a stop adjustment signal when the voltage reference level is not higher than a preset lower limit level, so as to end the adaptive adjustment of the voltage reference level.

[0012] In one embodiment, the battery cell voltage drop sensing circuit includes an analog-to-digital converter circuit for converting the battery cell voltage drop, which has an analog form, into a cell voltage drop sensing signal, which has a digital form.

[0013] In one embodiment, the power stage circuit includes a switching inductor power stage circuit, a switching capacitor power stage circuit, a low dropout linear regulator, or an AC / DC converter circuit.

[0014] In one embodiment, the charging control method further includes setting a start signal to an enable level to initiate the reference level adjustment step.

[0015] In one embodiment, the charging control method further includes: when a protection signal is at a prohibited level, setting the voltage reference level to the preset lower limit level to end the reference level adjustment step.

[0016] In one embodiment, the step of adaptively reducing the voltage reference level when the core voltage drop sensing signal exceeds the preset threshold further includes: maintaining the voltage reference level for a preset period after reducing the voltage reference level by the preset difference.

[0017] To address the shortcomings of existing technologies, this invention proposes a charging circuit and charging control method that can shorten charging time.

[0018] The advantage of this invention is that it can shorten the charging time by adjusting the voltage reference level.

[0019] The following detailed description through specific embodiments will make it easier to understand the purpose, technical content, features, and effects achieved by the present invention. Attached Figure Description

[0020] Figure 1A This is a schematic diagram showing a known charging circuit.

[0021] Figure 1B It is a graph showing the relationship between the charging voltage and charging current and time for a known charging circuit.

[0022] Figure 2A This is a circuit block diagram showing a charging circuit according to an embodiment of the present invention.

[0023] Figure 2B This is a schematic diagram illustrating the relationship between charging voltage, battery cell voltage drop, and charging current and time in a charging circuit according to an embodiment of the present invention and in the prior art.

[0024] Figure 2C This is a schematic diagram illustrating the relationship between battery cell voltage drop and charging current versus time in a charging circuit according to an embodiment of the present invention and in the prior art.

[0025] Figures 3A-3F This is a schematic flowchart illustrating the steps of a charging control method according to an embodiment of the present invention.

[0026] Figure 4 This is a schematic flowchart illustrating the steps of a charging control method according to an embodiment of the present invention.

[0027] Figure 5 This is a schematic flowchart illustrating the steps of a charging control method according to another embodiment of the present invention.

[0028] Figure 6 This is a schematic flowchart illustrating the steps of a charging control method according to another embodiment of the present invention.

[0029] Figures 7A-7K Displays synchronous or asynchronous buck, boost, reverse, buck-boost, boost-reverse, and flyback power stage circuits that switch between inductive power stage circuits.

[0030] Figure 8 This illustrates an embodiment of a switching capacitor power stage circuit.

[0031] Figure 9 An embodiment of a low-dropout linear regulator is shown.

[0032] Figure 10 This illustrates an embodiment of an AC / DC conversion circuit.

[0033] Explanation of symbols in the diagram

[0034] 10, 20: Charging circuit

[0035] 11, 21: Control circuit

[0036] 12, 22: Power stage circuits

[0037] 13, 23: Current feedback circuit

[0038] 14, 24: Voltage feedback circuit

[0039] 19, 29: Battery

[0040] 25: Battery cell voltage drop sensing circuit

[0041] 26: Adjusting the circuit

[0042] 261: Step-down circuit

[0043] 27: Timing Circuit

[0044] 291: Battery cell

[0045] 30, 40, 50, 60: Charging control methods

[0046] 301~308, 401~413, 501~518, 601~619, 3051, 3061, 30611, 30612, 30613a, 30613b: Steps

[0047] GND: Grounding potential

[0048] Ibat: Charging Current

[0049] Ict: Fixed current

[0050] Ibf: Final charging current

[0051] L: Inductance

[0052] LG, UG: Operation signals

[0053] LX1: First end

[0054] LX2: Second end

[0055] Oif: Current feedback signal

[0056] Ovf: Voltage feedback signal

[0057] QA, QB: Power Switch

[0058] Rpr: Resistance

[0059] Sa: Adjust signal

[0060] Sf1, Sf2: End adjustment signal

[0061] t0, t1, t1', t2, t2': Time points

[0062] Vbat: Charging voltage

[0063] Vbc: Cell voltage drop

[0064] Vch: Charging power supply

[0065] Vct: Fixed voltage

[0066] Vibat: Current sensing signal

[0067] Vin: Input power

[0068] VrefCC: Current reference level

[0069] VrefCV: Voltage Reference Level

[0070] Vth: Preset threshold

[0071] Vvbat: Voltage sensing signal

[0072] Vvbc: Core voltage drop sensing signal Detailed Implementation

[0073] The accompanying drawings in this invention are all schematic and are mainly intended to show the coupling relationship between various circuits and the relationship between various signal waveforms. The circuits, signal waveforms and frequencies are not drawn to scale.

[0074] Figure 2A This is a circuit block diagram showing a charging circuit according to an embodiment of the present invention. Figure 2A As shown, the charging circuit 20 of the present invention includes a control circuit 21, a power stage circuit 22, a current feedback circuit 23, a voltage feedback circuit 24, a battery cell voltage drop sensing circuit 25, an adjustment circuit 26, and a timing circuit 27. The power stage circuit 22 operates power switches QA and QB according to operation signals UG and LG to convert the input power supply Vin into a charging power supply Vch to charge the battery 29. The charging power supply Vch corresponds to the charging voltage Vbat and / or the charging current Ibat. The control circuit 21 is coupled to the power stage circuit 22 and generates operation signals UG and LG according to the current feedback signal Oif and the voltage feedback signal Ovf.

[0075] Figure 2AThe power stage circuit 22 shown is a buck power stage circuit in a switched inductor power stage circuit. According to the present invention, the power stage circuit 22 is not limited to a switched inductor power stage circuit; it can also be a switched capacitor power stage circuit, a low-dropout linear regulator, or an AC / DC converter circuit. The switched inductor power stage circuit can, for example, be a synchronous or asynchronous buck, boost, reverse, buck-boost, boost-reverse, or flyback power stage circuit, such as... Figures 7A-7K As shown. Additionally... Figure 8 An embodiment of a switching capacitor power stage circuit is shown; Figure 9 An embodiment of a low dropout linear regulator is shown; Figure 10 This illustrates an embodiment of an AC / DC conversion circuit.

[0076] The current feedback circuit 23 compares the current sensing signal Vibat, which is related to the charging current Ibat, with the current reference level VrefCC to generate a current feedback signal Oif. The voltage feedback circuit 24 compares the voltage sensing signal Vvbat, which is related to the charging voltage Vbat, with the voltage reference level VrefCV to generate a voltage feedback signal Ovf. The cell voltage drop sensing circuit 25 is coupled to the cell 291 of the battery 29 to sense the cell voltage drop Vbc of the cell 291 and generate a cell voltage drop sensing signal Vvbc. In one embodiment, the cell voltage drop sensing circuit 25 includes an analog-to-digital converter (ADC) to convert the cell voltage drop Vbc, which has an analog form, into a cell voltage drop sensing signal Vvbc, which has a digital form.

[0077] The adjustment circuit 26 is coupled to the battery cell voltage drop sensing circuit 25 and is used to generate an adjustment signal Sa based on the cell voltage drop sensing signal Vvbc to adaptively adjust the voltage reference level VrefCV. In one embodiment, the adjustment circuit 26 adaptively reduces the voltage reference level VrefCV when the cell voltage drop sensing signal Vvbc exceeds a preset threshold Vth. In one embodiment, the aforementioned preset threshold Vth is, for example, but not limited to, 4.2V or 4.4V. Figure 2A As shown, in one embodiment, the adjustment circuit 26 includes a step-down circuit 261, which adjusts the step signal to an enable level when the core voltage drop sensing signal Vvbc exceeds a preset threshold Vth, indicating that the core voltage drop sensing signal Vvbc exceeds the preset threshold Vth, and then lowers the voltage reference level VrefCV by a preset difference. In one embodiment, the aforementioned preset difference is, for example, but not limited to, 10mV. In one embodiment, after lowering the preset difference of the voltage reference level VrefCV, the adjustment circuit 26 maintains the lowered voltage reference level VrefCV for a preset time. In one embodiment, the aforementioned preset time is, for example, but not limited to, 32 microseconds (ms), 64ms, 128ms, or 256ms.

[0078] The timing circuit 27 is coupled to the adjustment circuit 26 and, based on the step signal at the prohibition level, indicates that the core voltage drop sensing signal Vvbc does not exceed a preset threshold Vth, timing a timeout period. At the end of the timeout period, while the step signal is still at the prohibition level, the timing circuit 27 generates an end adjustment signal Sf1 to terminate the adaptive adjustment of the voltage reference level VrefCV. In one embodiment, the aforementioned timeout period is, for example, but not limited to, 0.5s or 1s. The control circuit 21 generates an end adjustment signal Sf2 when the voltage reference level VrefCV is not higher than a preset lower limit level to terminate the adaptive adjustment of the voltage reference level VrefCV.

[0079] The power stage circuit 22 includes power switches QA and QB and an inductor L. Power switch QA is coupled between the input power supply Vin and the first terminal LX1 of the inductor L, while power switch QB is coupled between ground potential GND and the first terminal LX1 of the inductor L. Operating signals UG and LG are used to control power switches QA and QB, respectively, to switch the first terminal LX1 of the inductor L between the input power supply Vin and the ground potential GND. The charging power supply Vch is coupled to the second terminal LX2 of the inductor L, thereby converting the input power supply Vin into the charging power supply Vch to charge the battery 29.

[0080] Figure 2B This is a schematic diagram illustrating the relationship between the charging voltage Vbat, battery cell voltage drop, and charging current Ibat and time in a charging circuit according to an embodiment of the present invention and in the prior art. Figure 2C This is a schematic diagram illustrating the relationship between the battery cell voltage drop Vbc and the charging current Ibat versus time in a charging circuit according to an embodiment of the present invention and in the prior art. Figure 2B and 2C In the diagram, the gray lines represent the feature curves of existing technologies, while the black lines represent the feature curves of the present invention. For example... Figure 2B and 2C As shown, the charging circuit of the present invention requires significantly less time to charge the battery than... Figure 1A Existing technologies require less time to charge.

[0081] like Figure 2B As shown in the prior art, as mentioned above, during the period from time point t1 to the later part of time point t2, the charging efficiency is low due to the gradual decrease of the charging current Ibat. The longer this later part of the period with low charging efficiency is, the longer the charging time will be.

[0082] Please continue reading. Figure 2B According to the present invention, the charging voltage Vbat of the charging circuit (e.g.) Figure 2B (as indicated by the thick black solid line) and charging current Ibat (e.g.) Figure 2B The diagram illustrates the relationship between the current and time (shown by the thick black dashed line). From time point t0 to the early period of time point t1', the current feedback circuit 23 dominates the feedback control, adjusting the charging current Ibat to a fixed current Ict to charge the battery 19. From time point t1' to the later period of time point t2', the voltage feedback circuit 14 dominates the feedback control. During this later period, the voltage reference level VrefCV is adjusted in steps, decreasing by a preset difference each time, thus adaptively reducing the voltage reference level VrefCV. This causes the charging voltage Vbat to gradually decrease until the voltage reference level VrefCV is no higher than the preset lower limit level. At this point, the control circuit 21 generates a stop adjustment signal Sf2 to end the adaptive adjustment of the voltage reference level VrefCV and adjust the charging voltage Vbat to a fixed voltage Vct.

[0083] Comparing the characteristic curves of the present invention with those of the prior art, between time points t1 and t1', according to the present invention, the voltage reference level VrefCV is set at voltage Vct', which is higher than voltage Vct. Therefore, during this period, the charging circuit according to the present invention still charges the battery 19 with a higher fixed current Ict compared to the prior art, thus shortening the charging time.

[0084] like Figure 2C As shown, Figure 2C This is a schematic diagram illustrating the relationship between the battery cell voltage drop Vbc and the charging current Ibat and time in a charging circuit according to an embodiment of the present invention and in the prior art. As mentioned above, the charging circuit according to the present invention has a shorter charging time compared to the prior art. When the cell voltage drop sensing signal Vvbc, which is related to the battery cell voltage drop Vbc, exceeds a preset threshold Vth, the voltage reference level VrefCV is reduced by a preset difference, and for example, the reduced voltage reference level VrefCV is maintained for a preset period of time. Due to continuous charging, when the cell voltage drop sensing signal Vvbc exceeds the preset threshold Vth again, the voltage reference level VrefCV is reduced again by a preset difference, and the reduced voltage reference level VrefCV is maintained for another preset period of time until the voltage reference level VrefCV is not higher than a preset lower limit level, then the reference level adjustment step ends. This is the adaptive step of gradually reducing the voltage reference level VrefCV.

[0085] Figures 3A-3F This is a schematic flowchart illustrating the steps of a charging control method according to an embodiment of the present invention. Figure 3AAs shown, the charging control method 30 of the present invention includes step 301, operating at least one power switch according to an operation signal to control the conduction state of an inductor and convert the input power supply into a charging power supply, wherein the charging power supply includes a charging voltage and a charging current. Next, in step 302, an operation signal is generated based on a current feedback signal and a voltage feedback signal. Then, in step 303, a current sensing signal related to the charging current is compared with a current reference level to generate a current feedback signal. Next, in step 304, a voltage sensing signal related to the charging voltage is compared with a voltage reference level to generate a voltage feedback signal. Then, a reference level adjustment step is performed, which includes step 305, sensing the cell voltage drop inside the battery to generate a cell voltage drop sensing signal. Next, in step 306, an adjustment signal is generated based on the cell voltage drop sensing signal to adaptively adjust the voltage reference level.

[0086] like Figure 3B As shown, in one embodiment, step 306 may include step 3061, adaptively reducing the voltage reference level when the core voltage drop sensing signal exceeds a preset threshold. Figure 3C As shown, in one embodiment, step 3061 may include step 30611, where, when the core voltage drop sensing signal exceeds a preset threshold, the step signal is adjusted to an enable level to indicate that the core voltage drop sensing signal exceeds the preset threshold, and the voltage reference level is lowered by a preset difference. Next, in step 30612, the voltage reference level is maintained for a preset period. Then, the process can continue to step 30613a, where, based on the step signal being at an inhibit level, indicating that the core voltage drop sensing signal does not exceed the preset threshold, a timeout period is timed, and at the end of the timeout period, when the step signal is at an inhibit level, a termination adjustment signal is generated to end the reference level adjustment step. In another embodiment, the process can continue to step 30613b, where, when the voltage reference level is not higher than a preset lower limit level, a termination adjustment signal is generated to end the reference level adjustment step.

[0087] like Figure 3D As shown, step 305 may include step 3051, converting the battery cell voltage drop, which has an analog form, into a cell voltage drop sensing signal, which has a digital form. For example... Figure 3E As shown, the charging control method 30 of the present invention may further include step 307, setting the start signal to an enable level to initiate the reference level adjustment step. Figure 3F As shown, the charging control method 30 of the present invention may further include step 308, which sets the voltage reference level to a preset lower limit level when the protection signal is a prohibition level, so as to end the reference level adjustment step.

[0088] Figure 4 This is a schematic flowchart illustrating the steps of a charging control method according to an embodiment of the present invention. Figure 4As shown, the charging control method 40 of the present invention may include step 401, in which a protection signal is set to an enable level by software to activate a protection mechanism. Next, in step 402, the hardware verifies whether the analog-to-digital converter (ADC) is enabled and whether the activation signal of the channel in the ADC used to detect the battery cell voltage drop is at the enable level. If yes, proceed to step 403; otherwise, proceed to step 410. In step 403, the hardware verifies whether the battery cell voltage drop is greater than a preset threshold. If yes, proceed to step 404; otherwise, return to step 402. In one embodiment, the preset threshold is, for example, but not limited to, 4.2V or 4.4V.

[0089] In step 404, the hardware sends a signal to the system notifying that a preset threshold has been exceeded. Next, in step 405, the hardware checks whether the step signal is at the enable level to initiate the reference level adjustment procedure. If yes, proceed to step 406; otherwise, proceed to step 409. In step 406, the hardware lowers the voltage reference level by a preset difference. In one embodiment, the preset difference is, for example, but not limited to, 10mV. Next, in step 407, it checks whether the voltage reference level is less than or equal to a preset lower limit level. If yes, proceed to step 410; otherwise, proceed to step 408. In step 408, the voltage reference level is maintained for a preset time. In one embodiment, the preset time is, for example, but not limited to, 32ms, 64ms, 128ms, and 256ms. After step 408, the process returns to step 402.

[0090] In step 409, the hardware times the time and determines whether the timeout period has been exceeded. If yes, proceed to step 410; otherwise, return to step 402. In one embodiment, the aforementioned timeout period is, for example, but not limited to, 0.5s or 1s. In step 410, the hardware configures the voltage reference level to a preset lower limit level and sends a signal to the system to notify the program to end. Next, in step 411, the hardware confirms whether the protection signal is at the enable level. If yes, return to step 402; otherwise, proceed to step 413. In another embodiment, in step 412, when the protection signal is set to the disable level, the voltage reference level is set to the preset lower limit level. Then, in step 413, all programs end.

[0091] Figure 5 This is a schematic flowchart illustrating the steps of a charging control method according to another embodiment of the present invention. This embodiment uses hardware to implement the charging control method. This embodiment and... Figure 4The difference between this embodiment and the previous one is that the charging control method 50 in this embodiment includes step 501, inserting an external power source. Next, in step 502, the software logs initial settings. In one embodiment, the aforementioned initial settings include, but are not limited to, initial settings for a preset lower limit level, a preset threshold, a step signal, a preset time, and a voltage reference level. In one embodiment, the initial setting of the step signal is to set it to an enable level. Then, in step 503, the software sets ADC-related parameters and sets the start signal of the channel in the ADC used to detect battery cell voltage drop to an enable level (continuous mode measurement of battery cell voltage drop). Next, in step 504, the software confirms whether the battery cell voltage drop is less than the maximum external battery voltage and whether the battery exists. If yes, proceed to step 505; if no, return to step 503. In step 505, the software sets a protection signal to an enable level to activate the protection mechanism. Then, in step 506, the software sets the voltage reference level to the maximum external battery voltage. In one embodiment, the maximum external voltage of the aforementioned battery is, for example, but not limited to, 4.7V. After step 506, steps 507-518 are performed. Steps 507-518 are similar to... Figure 4 Steps 402-413 are omitted in detail here. This embodiment is similar to... Figure 4 Another difference in the embodiment is that after step 515 ends, the software receives a signal and sets the start signal to the disabled level, the protection signal to the disabled level, and the voltage reference level to the maximum value of the external battery voltage.

[0092] Figure 6 This is a flowchart illustrating the steps of a charging control method according to another embodiment of the present invention. In this embodiment, software issues commands to the hardware via a communication interface to implement the charging control method. Steps 601-609 and 611-619 are similar to... Figure 5 Steps 501-518 are omitted in detail here. This embodiment is similar to... Figure 5 The difference in this embodiment is that after step 609 ends, step 610 is performed. After receiving the signal sent by the hardware, the software reads the buffer within a preset time and issues an instruction to the hardware to execute the reference level adjustment procedure, and resets the preset timer. In one embodiment, the aforementioned preset time is, for example, but not limited to, 0.5s.

[0093] The present invention provides a charging circuit and its control method as described above, which can shorten the charging time by adjusting the voltage reference level.

[0094] The present invention has been described above with reference to preferred embodiments. However, the above description is only intended to facilitate understanding of the invention by those skilled in the art and is not intended to limit the broadest scope of the invention. The described embodiments are not limited to individual application and can also be used in combination. For example, two or more embodiments can be used in combination, and some components of one embodiment can be used to replace corresponding components in another embodiment. Furthermore, within the same spirit of the invention, those skilled in the art can conceive of various equivalent changes and combinations. For example, the phrase "processing or calculating based on a signal or generating an output result" in the present invention is not limited to the signal itself, but also includes, when necessary, performing voltage-to-current conversion, current-to-voltage conversion, and / or proportional conversion on the signal, and then processing or calculating based on the converted signal to generate an output result. Therefore, within the same spirit of the invention, those skilled in the art can conceive of various equivalent changes and combinations, and there are many ways to combine them, which will not be listed here. Therefore, the scope of the present invention should cover the above and all other equivalent changes.

Claims

1. A charging circuit, characterized in that, Include: A power stage circuit for operating at least one power switch therein according to an operation signal to convert an input power supply into a charging power supply for charging a battery, wherein the charging power supply includes a charging voltage and a charging current. A control circuit, coupled to the power stage circuit, is used to generate the operating signal based on a current feedback signal and a voltage feedback signal; A current feedback circuit is used to compare a current sensing signal related to the charging current with a current reference level to generate the current feedback signal. A voltage feedback circuit is used to compare a voltage sensing signal related to the charging voltage with a voltage reference level to generate the voltage feedback signal; A cell voltage drop sensing circuit is coupled to a cell of the battery to sense the cell voltage drop and generate a cell voltage drop sensing signal. as well as An adjustment circuit, coupled to the cell voltage drop sensing circuit, is used to generate an adjustment signal based on the cell voltage drop sensing signal to adaptively adjust the voltage reference level. The adjustment circuit adaptively lowers the voltage reference level when the core voltage drop sensing signal exceeds a preset threshold.

2. The charging circuit as described in claim 1, wherein, The adjustment circuit includes a step-down circuit, which adjusts the step-down signal to an enable level when the core voltage drop sensing signal exceeds the preset threshold, indicating that the core voltage drop sensing signal exceeds the preset threshold, and then lowers the voltage reference level by a preset difference.

3. The charging circuit as described in claim 2, wherein, It also includes a timing circuit coupled to the adjustment circuit, and according to the step signal at a prohibition level, indicating that the core voltage drop sensing signal does not exceed the preset threshold, the timing circuit times an overdue period. At an end point of the overdue period, and when the step signal is at the prohibition level, the timing circuit generates an end adjustment signal to end the adaptive adjustment of the voltage reference level.

4. The charging circuit as described in claim 2, wherein, When the voltage reference level is not higher than a preset lower limit level, the control circuit generates a stop adjustment signal to end the adaptive adjustment of the voltage reference level.

5. The charging circuit as described in claim 1, wherein, The battery cell voltage drop sensing circuit includes an analog-to-digital converter circuit for converting the battery cell voltage drop, which has an analog form, into a cell voltage drop sensing signal, which has a digital form.

6. The charging circuit as described in claim 1, wherein, The power stage circuit includes a switching inductor power stage circuit, a switching capacitor power stage circuit, a low dropout linear regulator, or an AC / DC converter circuit.

7. A charging control method for converting an input power source into a charging power source to charge a battery, characterized in that, The charging control method includes: Based on an operation signal, at least one power switch is operated to convert the input power supply into the charging power supply, wherein the charging power supply includes a charging voltage and a charging current. The operation signal is generated based on a current feedback signal and a voltage feedback signal; The current feedback signal is generated by comparing a current sensing signal related to the charging current with a current reference level. The voltage feedback signal is generated by comparing a voltage sensing signal related to the charging voltage with a voltage reference level. as well as A reference level adjustment procedure includes: The voltage drop of a battery cell inside the battery is sensed, and a cell voltage drop sensing signal is generated; and Based on the core voltage drop sensing signal, an adjustment signal is generated to adaptively adjust the voltage reference level; The step of generating the adjustment signal based on the core voltage drop sensing signal to adaptively adjust the voltage reference level includes: adaptively lowering the voltage reference level when the core voltage drop sensing signal exceeds a preset threshold.

8. The charging control method as described in claim 7, wherein, The step of adaptively reducing the voltage reference level when the core voltage drop sensing signal exceeds the preset threshold includes: when the core voltage drop sensing signal exceeds the preset threshold, adjusting a step signal to an enable level to indicate that the core voltage drop sensing signal exceeds the preset threshold, and reducing the voltage reference level by a preset difference.

9. The charging control method as described in claim 8, wherein, The step of adaptively reducing the voltage reference level when the core voltage drop sensing signal exceeds the preset threshold further includes: when the step signal is at a prohibition level, indicating that the core voltage drop sensing signal does not exceed the preset threshold, timing a timeout period, and at an end point of the timeout period, and when the step signal is at the prohibition level, generating an end adjustment signal to end the reference level adjustment step.

10. The charging control method as described in claim 8, wherein, The step of adaptively lowering the voltage reference level when the core voltage drop sensing signal exceeds the preset threshold further includes: generating an end adjustment signal when the voltage reference level is not higher than a preset lower limit level, so as to end the reference level adjustment step.

11. The charging control method as described in claim 7, wherein, The step of sensing the voltage drop of a battery cell inside the battery and generating a cell voltage drop sensing signal includes: converting the cell voltage drop, which has an analog form, into a cell voltage drop sensing signal, which has a digital form.

12. The charging control method as described in claim 7, wherein, It also includes setting a start signal to an enable level to initiate the reference level adjustment step.

13. The charging control method as described in claim 10, wherein, It also includes: when a protection signal is at the prohibition level, setting the voltage reference level to the preset lower limit level to end the reference level adjustment step.

14. The charging control method as described in claim 8, wherein, The step of adaptively reducing the voltage reference level when the core voltage drop sensing signal exceeds the preset threshold further includes: maintaining the voltage reference level for a preset period after reducing the preset difference in the voltage reference level.

15. The charging control method as described in claim 7, wherein, The power switch belongs to a power stage circuit, which includes a switching inductor power stage circuit, a switching capacitor power stage circuit, a low dropout linear regulator, or an AC / DC conversion circuit.

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