Charge pump pre-charging circuit and electronic device

Abstract

The present invention provides a charge pump pre-charge circuit and an electronic device. The power transistor unit thereof includes a first, a second, a third, and a fourth switching transistor which are electrically connected. The first switching transistor is connected to a supply voltage and is coupled to a bootstrap capacitor through a diode. The bootstrap capacitor is respectively coupled to the second switching transistor and a flying capacitor. The flying capacitor is respectively coupled to the fourth switching transistor and the pre-charge circuit. The fourth switching transistor is grounded. One end of the second switching transistor is respectively coupled to the output terminal of the charge pump and an output capacitor; in the pre-charge circuit, a fifth switching transistor is coupled to the flying capacitor through a current-limiting resistor, and the other end thereof is grounded. A protection module and an insertion detection module are both coupled to the output terminal of the charge pump; thus, when the device is connected to the charge pump, the fifth switching transistor is controlled to be turned on within a set time duration, and the battery is used to charge the flying capacitor, simplifying the pre-charge circuit. Therefore, the present invention can quickly pre-charge the charge pump without the need for external devices to confirm whether the pre-charge is completed.

Description

Technical Field

[0001] The present invention relates to the field of power electronics, and in particular, to a charge pump pre-charge circuit and an electronic device. Background Art

[0002] In recent years, as a non-sensing DC-DC converter, a charge pump uses a capacitor as an energy storage element for voltage conversion. Due to its advantages such as high conversion efficiency, it has been widely used in the power supply field, especially in the fast charging field.

[0003] In a power conversion circuit applying a charge pump, flying capacitors and bootstrap capacitors (as shown in Figure 1 ) are often required. The flying capacitor is used to complete the transfer of the stored charge from the input to the output, so that the voltage at the output end of the power conversion circuit can float to different voltage levels. The bootstrap capacitor is used to complete the bootstrap boost of the driving circuit of the high-side power transistor. In actual applications, before the power conversion circuit starts to work, the flying capacitor needs to be pre-charged, and the voltage value across it needs to be charged to be close to the pre-output voltage of the power conversion circuit. If no pre-charge is performed, there will be a huge current in the circuit at the moment when the power switch is turned on, thus burning out all the power devices in the circuit.

[0004] In the current circuit soft start architecture, please refer to Figure 1 . Generally, a current source is used to charge the flying capacitor. However, this charging speed is slow. In actual use, it is necessary to wait until the external overvoltage protection circuit is turned on and the current source is established before using the mirror current to charge the flying capacitor. Moreover, this charging method also requires an additional comparator to compare the voltage across the flying capacitor with the pre-output voltage to determine the end time of the pre-charge.

[0005] Therefore, how to quickly pre-charge the charge pump and simplify the pre-charge circuit without the need for external devices to confirm whether the pre-charge is completed has become a technical problem that the industry urgently needs to solve currently. Summary of the Invention

[0006] The present invention provides a charge pump pre-charge circuit and an electronic device to solve the problem of how to quickly pre-charge the charge pump and simplify the pre-charge circuit without the need for external devices to confirm whether the pre-charge is completed.

[0007] According to a first aspect of the present invention, a charge pump pre-charge circuit is provided. The charge pump is used to charge the battery of an accessed device. The charge pump includes N power modules, and each group of power modules includes a power transistor unit, a bootstrap capacitor, and a flying capacitor, where N is a positive integer. Among them:

[0008] The power transistor unit includes a first switch transistor, a second switch transistor, a third switch transistor, and a fourth switch transistor that are electrically connected in sequence. The first end of the first switch transistor is coupled to a supply voltage. The first end of the first switch transistor is also coupled to the first end of the bootstrap capacitor through a diode. The second end of the bootstrap capacitor is coupled to the first end of the second switch transistor and the first end of the flying capacitor respectively. The second end of the flying capacitor is coupled to the first end of the fourth switch transistor and the first end of the pre-charge circuit respectively. The second end of the fourth switch transistor is grounded. The second end of the second switch transistor serves as the output end of the power module, which is coupled to the output end of the charge pump and the first end of the output capacitor respectively. The negative electrode of the battery and the second end of the output capacitor are both grounded;

[0009] The pre-charge circuit includes a protection module, an insertion detection module, a control module, a fifth switch transistor, and a current-limiting resistor. The first end of the fifth switch transistor is coupled to the second end of the flying capacitor through the current-limiting resistor. The second end of the fifth switch transistor is grounded. The first end of the protection module and the first end of the insertion detection module are both coupled to the output end of the charge pump. The second end of the protection module is grounded. The second end of the insertion detection module is coupled to the first end of the control module. The second end of the control module is coupled to the control end of the fifth switch transistor. Wherein:

[0010] The insertion detection module is configured to monitor the voltage at its first end in real time and output a first signal to the control module according to the detected voltage. Wherein, the first signal is used to indicate whether the device is connected to the charge pump;

[0011] The control module is configured to: set a set duration. When the first signal indicates that the device is connected to the charge pump, control the fifth switch transistor to conduct within the set duration and disconnect after exceeding the set duration. When the first signal indicates that the device is not connected to the charge pump, control the fifth switch transistor to disconnect.

[0012] Optionally, the first switch transistor, the second switch transistor, the third switch transistor, and the fourth switch transistor are NMOS transistors or NPN-type BJT transistors.

[0013] Optionally, the control module is specifically configured to:

[0014] When the first signal indicates that the device is connected to the charge pump, output a high level to the control end of the fifth switch transistor through its second end within the set duration to control the fifth switch transistor to conduct, and output a low level to the control end of the fifth switch transistor through its second end after exceeding the set duration to control the fifth switch transistor to disconnect;

[0015] When the first signal indicates that the device is not connected to the charge pump, a low level is output to the control terminal of the fifth switching transistor through its second terminal to control the fifth switching transistor to turn off.

[0016] Optionally, the control module is further configured to set an anti-spike pulse duration; the control module includes a first timing unit and a logic control unit; wherein:

[0017] The first terminal of the first timing unit is coupled to the first terminal of the insertion detection module, its second terminal is coupled to a clock signal, and its third terminal is coupled to the first terminal of the logic control unit to output a first time signal; the second terminal of the logic control unit receives the clock signal, and its third terminal is coupled to the control terminal of the fifth switching transistor; wherein, the first time signal includes a first sub-signal and a second sub-signal;

[0018] Wherein, the first timing unit is configured to: only when the first signal indicates that the device is connected to the charge pump, start timing the access time of the device, and output the first sub-signal to the first terminal of the logic control unit after the anti-spike pulse duration; otherwise, output the second sub-signal to the first terminal of the logic control unit;

[0019] The logic control unit is configured to: start timing when receiving the first sub-signal at its first terminal, output a high level to the control terminal of the fifth switching transistor through its second terminal within the set duration to control the fifth switching transistor to turn on, and output a low level to the control terminal of the fifth switching transistor through its second terminal after exceeding the set duration to control the fifth switching transistor to turn off;

[0020] When receiving the second sub-signal at its first terminal, a low level is output to the control terminal of the fifth switching transistor through its second terminal to control the fifth switching transistor to turn off.

[0021] Optionally, the fourth terminal of the logic control unit receives an enable clock signal to set the set duration, and its fifth terminal receives a power-on reset signal.

[0022] Optionally, the insertion detection module includes a comparator;

[0023] The non-inverting input terminal of the comparator is coupled to the output terminal of the charge pump, its inverting input terminal receives a reference voltage, and its output terminal is coupled to the first terminal of the control module.

[0024] Optionally, the protection module includes a first capacitor and a first resistor;

[0025] The first end of the first capacitor and the first end of the first resistor are both coupled to the output terminal of the charge pump, and the second end of the first capacitor and the second end of the first resistor are both grounded.

[0026] Optionally, the protection module includes a second capacitor and a sixth switching tube;

[0027] The first end of the second capacitor and the first end of the sixth switching tube are both coupled to the output terminal of the charge pump, the second end of the second capacitor and the second end of the sixth switching tube are both grounded, and the control end of the sixth switching tube is coupled to the second end of the control module.

[0028] Optionally, the control module is further configured to:

[0029] When the first signal indicates that the device is accessing the charge pump, control the sixth switching tube to conduct within the set duration and turn off after exceeding the set duration; when the first signal indicates that the device is not accessing the charge pump, control the sixth switching tube to turn off.

[0030] Optionally, the charge pump is a half-voltage power conversion circuit.

[0031] According to a third aspect of the present invention, there is provided an electronic device including the charge pump precharging circuit provided in any one of the first aspects of the present invention.

[0032] In the charge pump precharging circuit and the electronic device provided by the present invention, the power transistor unit includes a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube that are electrically connected. The first switching tube is coupled to a supply voltage, and it is also coupled to a bootstrap capacitor through a diode. The bootstrap capacitor is respectively coupled to the second switching tube and a flying capacitor. The flying capacitor is respectively coupled to the fourth switching tube and the precharging circuit. The fourth switching tube is also grounded. One end of the second switching tube serves as the output terminal of the power module, and it is also respectively coupled to the output terminal of the charge pump and an output capacitor. The negative electrode of the battery and the output capacitor are both grounded; in the precharging circuit, its fifth switching tube is coupled to the flying capacitor through a current limiting resistor. The protection module and the insertion detection module are both coupled to the output terminal of the charge pump; the protection module and the fifth switching tube are grounded; when the device accesses the charge pump, control the fifth switching tube to conduct within a set duration, and use the battery to charge the flying capacitor, simplifying the precharging circuit. Thus, the present invention can quickly precharge the charge pump without the need for external devices to confirm whether the precharging is completed. Description of the Drawings

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0034] Figure 1 is a schematic diagram of the structure of a charge pump pre - charging circuit in the prior art;

[0035] Figure 2 is a schematic diagram of the structure of a charge pump pre - charging circuit in an embodiment of the present invention Figure 1 ;

[0036] Figure 3 is a schematic diagram of the structure of a charge pump pre - charging circuit in an embodiment of the present invention Figure 2 ;

[0037] Figure 4 is a schematic diagram of the structure of a charge pump pre - charging circuit in an embodiment of the present invention Figure 3 ;

[0038] Description of reference numerals:

[0039] 11 - Power module;

[0040] 21 - Protection module;

[0041] 22 - Insertion detection module;

[0042] 23 - Control module;

[0043] 231 - First timing unit;

[0044] 232 - Logic control unit;

[0045] Cboot - Bootstrap capacitor;

[0046] Cfly - Flying capacitor;

[0047] Q1 - First switching transistor;

[0048] Q2 - Second switching transistor;

[0049] Q3 - Third switching transistor;

[0050] Q4 - Fourth switching transistor;

[0051] Q9 - Fifth switching transistor;

[0052] Q10 - Tenth switching transistor;

[0053] Q11 - Sixth switching transistor;

[0054] PMID - Power supply voltage;

[0055] Cout - Output capacitor;

[0056] RL - Current - limiting resistor;

[0057] CLK - Clock signal;

[0058] EN_CLK - Enable clock signal;

[0059] POR - Power - on reset signal;

[0060] C1 - First capacitor;

[0061] C2 - Second capacitor;

[0062] R1 - First resistor. Detailed implementation manners

[0063] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0064] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above - mentioned accompanying drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non - exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0065] Next, the technical solutions of the present invention will be described in detail with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0066] In view of the prior art, it is difficult to quickly pre-charge a charge pump without an external device to confirm whether the pre-charging is completed and simplify the pre-charging circuit. The present invention provides a charge pump pre-charging circuit and an electronic device. The power transistor unit thereof includes a first switch transistor, a second switch transistor, a third switch transistor, and a fourth switch transistor that are electrically connected. The first switch transistor is coupled to a supply voltage, and it is also coupled to a bootstrap capacitor through a diode. The bootstrap capacitor is respectively coupled to the second switch transistor and the flying capacitor. The flying capacitor is respectively coupled to the fourth switch transistor and the pre-charging circuit. The fourth switch transistor is also grounded. One end of the second switch transistor serves as the output end of the power module, and it is also respectively coupled to the output end of the charge pump and the output capacitor. The negative electrode of the battery and the output capacitor are both grounded; in the pre-charging circuit, a fifth switch transistor is coupled to the flying capacitor through a current-limiting resistor. The protection module and the insertion detection module are both coupled to the output end of the charge pump; the protection module and the fifth switch transistor are grounded; when the device accesses the charge pump, the fifth switch transistor is controlled to conduct within a set time period, and the battery is used to charge the flying capacitor, simplifying the pre-charging circuit. Therefore, the present invention can quickly pre-charge the charge pump without an external device to confirm whether the pre-charging is completed.

[0067] Please refer to Figure 2 , an embodiment of the present invention provides a charge pump pre-charging circuit. The charge pump is used to charge the battery of the accessed device. The charge pump is characterized in that the charge pump includes N power modules 11. Each group of power modules 11 includes a power transistor unit, a bootstrap capacitor Cboot, and a flying capacitor Cfly, where N is a positive integer; where:

[0068] Taking Figure 2 the power transistor unit on the left as an example, the power transistor unit includes a first switch transistor Q1, a second switch transistor Q2, a third switch transistor Q3, and a fourth switch transistor Q4 that are sequentially electrically connected. The first end of the first switch transistor Q1 is coupled to a supply voltage PMID. The first end of the first switch transistor Q1 is also coupled to the first end of the bootstrap capacitor Cboot1 through a diode D9. The second end of the bootstrap capacitor Cboot1 is respectively coupled to the first end of the second switch transistor Q2 and the first end of the flying capacitor Cfly1. The second end of the flying capacitor Cfly1 is respectively coupled to the first end of the fourth switch transistor Q4 and the first end of the pre-charging circuit. The second end of the fourth switch transistor Q4 is grounded. The second end of the second switch transistor Q2 serves as the output end of the power module 11, and it is respectively coupled to the output end of the charge pump and the first end of the output capacitor Cout. The negative electrode of the battery and the second end of the output capacitor Cout are both grounded;

[0069] The pre-charge circuit includes a protection module 21, an insertion detection module 22, a control module 23, a fifth switch Q9, and a current-limiting resistor RL1. The first end of the fifth switch Q9 is coupled to the second end of the flying capacitor Cfly through the current-limiting resistor RL1. The second end of the fifth switch Q9 is grounded. The first ends of the protection module 21 and the insertion detection module 22 are both coupled to the output end of the charge pump. The second end of the protection module 21 is grounded. The second end of the insertion detection module 22 is coupled to the first end of the control module 23. The second end of the control module 23 is coupled to the control end of the fifth switch Q9. Wherein:

[0070] The insertion detection module 22 is configured to monitor the voltage VBAT at its first end in real time and output a first signal to the control module 23 according to the detected voltage. Wherein, the first signal is used to indicate whether the device is connected to the charge pump.

[0071] The control module 23 is configured to: set a preset duration. When the first signal indicates that the device is connected to the charge pump, control the fifth switch Q9 to conduct within the preset duration and disconnect after exceeding the preset duration. When the first signal indicates that the device is not connected to the charge pump, control the fifth switch Q9 to disconnect.

[0072] Wherein, the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 are NMOS transistors or NPN bipolar junction transistors (BJTs).

[0073] Regarding the power module on the right in Figure 2 The connection mode of the power module on the right is the same as that of the power transistor module on the left. In one example, the control module 23 is further coupled to the control end of the tenth switch Q10 ( Figure 2 not shown in the figure) for controlling the on / off of the tenth switch Q10. Wherein, when the first signal indicates that the device is connected to the charge pump, control the tenth switch Q10 to conduct within the preset duration and disconnect after exceeding the preset duration. When the first signal indicates that the device is not connected to the charge pump, control the tenth switch Q10 to disconnect.

[0074] In the case of multiple power modules, in a preferred embodiment, the control module 23 is further configured to:

[0075] Charge the flying capacitors Cfly corresponding to each power module in a predetermined order.

[0076] In Figure 2 the example shown, the charge pump is a half-voltage power conversion circuit, which includes two power modules 11. Here, this is taken as an example for further elaboration:

[0077] In the 2:1 half-voltage power conversion circuit, the output terminal of the charge pump is coupled to the battery of the device, and the voltage value of the power supply voltage PMID is set to twice the voltage value of the battery. Due to voltage loss caused by its circuit components, in actual settings, the voltage value of the power supply voltage PMID is set to be slightly greater than twice the voltage value of the battery.

[0078] When the half-voltage power conversion circuit is operating normally, taking the power module 11 on the left as an example, the control terminals of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, and the fourth switch tube Q4 respectively receive the first control signal CHG1, the second control signal DHG1, the third control signal CLG1, and the fourth control signal DLG1; the on or off duration of each switch tube is set according to the number of power modules 11 in the charge pump;

[0079] Among them, if the clock signal CLK received by the charge pump is in the first phase, control the first switch tube Q1 and the third switch tube Q3 to close, and the second switch tube Q2 and the fourth switch tube Q4 to disconnect. The flying capacitor Cfly and the output capacitor Cout are connected in series for voltage division. In this case:

[0080] Vcfly + Vcout = VIN;

[0081] If the clock signal CLK received by the charge pump is in the second phase, control the second switch tube Q2 and the fourth switch tube Q4 to close, and the first switch tube Q1 and the third switch tube Q3 to disconnect. The flying capacitor Cfly and the output capacitor Cout are connected in parallel. In this case:

[0082] Vcfly = Vcout;

[0083] Among them, Vcfly is the voltage value of the flying capacitor Cfly, Vcout is the voltage value of the output capacitor Cout, and VIN is the voltage value at the second end of the bootstrap capacitor Cboot.

[0084] In summary, the voltage value Vcout of the output capacitor Cout = VIN / 2; according to the principle of power conservation, the current Iout flowing into the battery = 2 * Ivin; where Ivin is the current value of the current flowing through the second switch tube Q2 or the third switch tube Q3.

[0085] According to the working principle of the power conversion circuit, before the power conversion circuit starts to work, the flying capacitor Cfly needs to be pre-charged, and the voltage across it needs to be charged to a value close to the pre-output voltage of the power conversion circuit. If pre-charging is not carried out, there will be a huge current in the circuit at the moment when the power switch is turned on, thus burning out all the power devices in the circuit.

[0086] Please refer to Figure 2 , when the first signal received by the control module 23 indicates that the device is connected to the charge pump, the fifth switching transistor Q9 is controlled to conduct within the set duration. During this period, since the second end of the flying capacitor Cfly is grounded through the current-limiting resistor RL1 and the fifth switching transistor Q9 in sequence, the battery charges the flying capacitor Cfly through the body diode of the second switching transistor Q2, so that the voltage value at the first end of the flying capacitor Cfly is the voltage value of the battery minus the voltage drop of the body diode, and the voltage value at its second end is close to the ground potential, thereby enabling the voltage values across the flying capacitor Cfly to be charged to a value close to the pre-output voltage of the power conversion circuit (i.e., the voltage of the battery minus the voltage drop of the body diode) within the set duration.

[0087] In an example, when the first signal received by the control module 23 indicates that the device is connected to the charge pump, an on signal PRE_CHG is output to the control terminal of the fifth switching transistor Q9 to control the fifth switching transistor Q9 to conduct within the set duration.

[0088] In a specific implementation manner, the control module 23 is specifically configured as:

[0089] When the first signal indicates that the device is connected to the charge pump, a high level is output to the control terminal of the fifth switching transistor Q9 through its second end within the set duration to control the fifth switching transistor Q9 to conduct, and a low level is output to the control terminal of the fifth switching transistor Q9 through its second end after exceeding the set duration to control the fifth switching transistor Q9 to turn off;

[0090] When the first signal indicates that the device is not connected to the charge pump, a low level is output to the control terminal of the fifth switching transistor Q9 through its second end to control the fifth switching transistor Q9 to turn off.

[0091] In this case, as an example, the fifth switching transistor Q9 is an NMOS transistor or an NPN-type BJT transistor. Of course, the present invention is not limited thereto, and a PMOS transistor or the like can also be selected. Correspondingly, the control module 23 can be configured to: output a low level from its second terminal to the control terminal of the fifth switching transistor Q9 within the set duration to control the fifth switching transistor Q9 to conduct; output a high level from its second terminal to the control terminal of the fifth switching transistor Q9 after exceeding the set duration to control the fifth switching transistor Q9 to turn off; when the first signal indicates that the device is not connected to the charge pump, output a high level from its second terminal to the control terminal of the fifth switching transistor Q9 to control the fifth switching transistor Q9 to turn off. Those skilled in the art can select other switching elements and the type of signal for controlling the fifth switching transistor Q9 output by the control module 23 according to needs.

[0092] In actual use, if the battery of the device is connected to the charge pump, due to the effects of components such as the inductance and capacitance of electronic components, an instantaneous high voltage much higher than the normal operating voltage will be generated in the system. To avoid damage to the charge pump by this instantaneous high voltage, the charge pump can be allowed to operate normally after the time when such an instantaneous high voltage may be generated has passed. In one embodiment, the control module 23 is further configured to set an anti-spike pulse duration; in this case, please refer to Figure 3 , the control module 23 includes a first timing unit 231 and a logic control unit 232; wherein:

[0093] The first end of the first timing unit 231 is coupled to the first end of the insertion detection module 22, its second end is coupled to a clock signal CLK, and its third end is coupled to the first end of the logic control unit 232 to output a first time signal; the second end of the logic control unit 232 receives the clock signal CLK, and its third end is coupled to the control terminal of the fifth switching transistor Q9; wherein, the first time signal includes a first sub-signal and a second sub-signal;

[0094] Wherein, the first timing unit 231 is configured to: start timing the access time of the device only when the first signal indicates that the device is connected to the charge pump, and output the first sub-signal to the first end of the logic control unit 232 after the anti-spike pulse duration; otherwise, output the second sub-signal to the first end of the logic control unit 232;

[0095] The logic control unit 232 is configured to: start timing when receiving the first sub-signal at its first end, output a high level to the control end of the fifth switching transistor Q9 through its second end within the set duration to control the fifth switching transistor Q9 to conduct, and output a low level to the control end of the fifth switching transistor Q9 through its second end after exceeding the set duration to control the fifth switching transistor Q9 to turn off;

[0096] When receiving the second sub-signal at its first end, it outputs a low level to the control end of the fifth switching transistor Q9 through its second end to control the fifth switching transistor Q9 to turn off.

[0097] In a preferred embodiment, please refer to Figure 3 , the fourth end of the logic control unit 232 receives an enable clock signal EN_CLK to set the set duration, and its fifth end receives a power-on reset signal POR.

[0098] Regarding other modules of the pre-charge circuit, the specific description is as follows:

[0099] In one embodiment, please refer to Figure 3 , the insertion detection module 22 includes a comparator;

[0100] The non-inverting input terminal of the comparator is coupled to the output terminal of the charge pump, its inverting input terminal receives a reference voltage Vref, and its output terminal is coupled to the first end of the control module 23.

[0101] In this case, by comparing the voltage value of the voltage at the output terminal of the charge pump and the voltage value of the reference voltage Vref, it is possible to monitor whether the battery of the device is connected to the charge pump while avoiding the problem that a battery with a lower voltage is connected to the charge pump, which may cause damage to the device.

[0102] It should be understood that the specific components of the insertion detection module 22 are only examples. In other examples, it is also possible to monitor through the voltage of the differential data line corresponding to its downstream port.

[0103] In one embodiment, please refer to Figure 4 , the protection module 21 includes a first capacitor C1 and a first resistor R1;

[0104] The first end of the first capacitor C1 and the first end of the first resistor R1 are both coupled to the output terminal of the charge pump, and the second end of the first capacitor C1 and the second end of the first resistor R1 are both grounded.

[0105] Among them, if the first capacitor C1 is a large capacitor, it can filter low-frequency interference signals; if the first capacitor C1 is a small capacitor, it can filter high-frequency interference signals; and the conduction impedance of the first resistor R1 is relatively high.

[0106] In another embodiment, please refer to Figure 3 , the protection module 21 includes a second capacitor C2 and a sixth switching transistor Q11;

[0107] The first end of the second capacitor C2 and the first end of the sixth switching transistor are both coupled to the output end of the charge pump, the second end of the second capacitor C2 and the second end of the sixth switching transistor Q11 are both grounded, and the control end of the sixth switching transistor Q11 is coupled to the second end of the control module 23.

[0108] Among them, if the second capacitor C2 is a large capacitor, it can filter low-frequency interference signals; if the second capacitor C2 is a small capacitor, it can filter high-frequency interference signals. When the sixth switching transistor Q11 is turned on, it can be regarded as a switching transistor with a weak pull-down function, and its conduction impedance is relatively high, so as to protect the circuit.

[0109] In this case, in one embodiment, the control module 23 is further configured to:

[0110] When the first signal indicates that the device is accessing the charge pump, control the sixth switching transistor Q11 to turn on within the set duration and turn off after exceeding the set duration; when the first signal indicates that the device is not accessing the charge pump, control the sixth switching transistor Q11 to turn off.

[0111] Of course, the specific implementation manner of the protection circuit of the present invention is not limited, and any foreseeable circuit structure is within the protection scope of the present invention. For example, introducing a TVS diode, etc. Those skilled in the art can set the protection module 21 as needed.

[0112] In addition, the embodiment of the present invention further provides an electronic device, including the above-mentioned charge pump pre-charging circuit. As an example, the device can be a fast charging plug, a power bank, and of course, it can also be other devices that need to be powered.

[0113] In summary, in the present invention, the power tube unit includes a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube that are electrically connected. The first switch tube is coupled to a supply voltage, and is also coupled to a bootstrap capacitor through a diode. The bootstrap capacitor is respectively coupled to the second switch tube and a flying capacitor. The flying capacitor is respectively coupled to the fourth switch tube and a pre-charging circuit. The fourth switch tube is also grounded. One end of the second switch tube serves as the output end of the power module, and is also respectively coupled to the output end of the charge pump and an output capacitor. The output capacitor is grounded. In the pre-charging circuit, a fifth switch tube is coupled to the flying capacitor through a current-limiting resistor. The protection module and the insertion detection module are both coupled to the output end of the charge pump. The protection module and the fifth switch tube are grounded. When the device is connected to the charge pump, the fifth switch tube is controlled to conduct within a set time duration, and the battery is used to charge the flying capacitor, simplifying the pre-charging circuit. Thus, the present invention can quickly pre-charge the charge pump without the need for external devices to confirm whether the pre-charging is completed.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A charge pump pre-charge circuit, the charge pump being used to charge the battery of an accessed device, characterized in that The charge pump includes N power modules, and each group of power modules includes a power transistor unit, a bootstrap capacitor, and a flying capacitor, where N is a positive integer; among them: The power transistor unit includes a first switch transistor, a second switch transistor, a third switch transistor, and a fourth switch transistor that are electrically connected in sequence. The first end of the first switch transistor is coupled to a supply voltage, and the first end of the first switch transistor is also coupled to the first end of the bootstrap capacitor through a diode. The second end of the bootstrap capacitor is respectively coupled to the first end of the second switch transistor and the first end of the flying capacitor. The second end of the flying capacitor is respectively coupled to the first end of the fourth switch transistor and the first end of the pre-charge circuit. The second end of the fourth switch transistor is grounded. The second end of the second switch transistor serves as the output end of the power module, and is respectively coupled to the output end of the charge pump and the first end of the output capacitor. The negative electrode of the battery and the second end of the output capacitor are both grounded; The pre-charge circuit includes a protection module, an insertion detection module, a control module, a fifth switch transistor, and a current-limiting resistor; the first end of the fifth switch transistor is coupled to the second end of the flying capacitor through the current-limiting resistor, the second end of the fifth switch transistor is grounded, the first end of the protection module and the first end of the insertion detection module are both coupled to the output end of the charge pump, the second end of the protection module is grounded, the second end of the insertion detection module is coupled to the first end of the control module, and the second end of the control module is coupled to the control end of the fifth switch transistor; among them: The insertion detection module is used to monitor the voltage at its first end in real time, and output a first signal to the control module according to the detected voltage. Among them, the first signal is used to represent whether the device is connected to the charge pump; The insertion detection module includes a comparator; the non-inverting input terminal of the comparator is coupled to the output end of the charge pump, its inverting input terminal receives a reference voltage, and its output end is coupled to the first end of the control module; The control module is configured to: set a set duration. When the first signal indicates that the device is connected to the charge pump, control the fifth switch transistor to conduct within the set duration and disconnect after exceeding the set duration; when the first signal indicates that the device is not connected to the charge pump, control the fifth switch transistor to disconnect; Among them, the first switch transistor, the second switch transistor, the third switch transistor, and the fourth switch transistor are NMOS transistors or NPN-type BJT transistors.

2. The charge pump precharge circuit according to claim 1, wherein The control module is specifically configured to: When the first signal indicates that the device is connected to the charge pump, output a high level to the control end of the fifth switch transistor through its second end within the set duration to control the fifth switch transistor to conduct, and output a low level to the control end of the fifth switch transistor through its second end after exceeding the set duration to control the fifth switch transistor to disconnect; When the first signal indicates that the device is not connected to the charge pump, output a low level to the control end of the fifth switch transistor through its second end to control the fifth switch transistor to disconnect.

3. The charge pump precharge circuit according to claim 2, wherein The control module is further configured to set an anti-spike pulse duration; the control module includes a first timing unit and a logic control unit; wherein: A first end of the first timing unit is coupled to a first end of the insertion detection module, a second end thereof is coupled to a clock signal, and a third end thereof is coupled to a first end of the logic control unit to output a first time signal; a second end of the logic control unit receives the clock signal, and a third end thereof is coupled to a control end of the fifth switching tube; wherein, the first time signal includes a first sub-signal and a second sub-signal; Wherein, the first timing unit is configured to: start timing the access time of the device only when the first signal indicates that the device accesses the charge pump, and output the first sub-signal to the first end of the logic control unit after the anti-spike pulse duration; otherwise, output the second sub-signal to the first end of the logic control unit; The logic control unit is configured to: start timing when receiving the first sub-signal at its first end, output a high level to the control end of the fifth switching tube through its second end within the set duration to control the fifth switching tube to conduct, and output a low level to the control end of the fifth switching tube through its second end after exceeding the set duration to control the fifth switching tube to turn off; When receiving the second sub-signal at its first end, output a low level to the control end of the fifth switching tube through its second end to control the fifth switching tube to turn off.

4. The charge pump precharge circuit according to claim 3, wherein A fourth end of the logic control unit receives an enable clock signal to set the set duration, and a fifth end thereof receives a power-on reset signal.

5. The charge pump pre-charge circuit according to claim 1, wherein The protection module includes a first capacitor and a first resistor; A first end of the first capacitor and a first end of the first resistor are both coupled to an output end of the charge pump, and a second end of the first capacitor and a second end of the first resistor are both grounded.

6. The charge pump precharge circuit according to claim 1, wherein The protection module includes a second capacitor and a sixth switching tube; A first end of the second capacitor and a first end of the sixth switching tube are both coupled to an output end of the charge pump, a second end of the second capacitor and a second end of the sixth switching tube are both grounded, and a control end of the sixth switching tube is coupled to a second end of the control module.

7. The charge pump precharge circuit according to claim 6, wherein The control module is further configured to: When the first signal indicates that the device accesses the charge pump, control the sixth switching tube to conduct within the set duration and turn off after exceeding the set duration; when the first signal indicates that the device does not access the charge pump, control the sixth switching tube to turn off.

8. The charge pump pre-charge circuit according to any one of claims 1-7, characterized in that, The charge pump is a half-voltage power conversion circuit.

9. An electronic device, characterized in that, Including the charge pump pre-charge circuit according to any one of claims 1-8.

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