Converter for energy storage elements

Abstract

A converter for energy storage element, comprising: a charger / load connection port, an energy storage element connection port, a load detection circuit, a body diode control circuit, an NMOS power tube, a PMOS power tube, a logic control circuit, a drive circuit, a working mode detection circuit, wherein: the input terminals of the logic control circuit, the working mode detection circuit and the body diode control circuit are connected to the first terminal of the charger / load connection port and the second terminal of the energy storage element connection port, the logic control circuit controls the working of the converter, the working mode detection circuit determines the working mode of the converter, the drive circuit controls the on-off of the NMOS power tube and the PMOS power tube according to the working mode, the load detection circuit detects whether the charger / load connection port is connected to a load, and the body diode control circuit determines the connection relationship of the substrate of the PMOS power tube according to the relationship between its respective inputs.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the field of electronic circuits, and in particular, to a converter for an energy storage element. Background Art

[0002] With the development of the electronics industry, a wide variety of electronic products have emerged, meeting people's needs in all aspects. At the same time, people have increasingly higher requirements for the various performance indicators of electronic products. For example, they hope that electronic products will be more energy-saving and environmentally friendly, more efficient, and lower in cost. At the same time, they also hope that electronic products will have a longer battery life. This demand provides a broad application space for mobile power supplies. As a portable energy storage device, mobile power supplies are mainly used as portable chargers for handheld mobile devices and other consumer electronic products (such as mobile phones and laptops), especially in situations where there is no external power supply. The main components of a mobile power supply include: a battery for storing electrical energy, a boost circuit (DC-DC converter) for stabilizing the output voltage, and a charging circuit. Based on these components, the mobile power supply can have the following three operating modes: standby mode, charging mode, and boost mode.

[0003] There are two types of converters for mobile components on the market today: a dual-port converter and a single-port converter.

[0004] In a dual-port converter, a diode is used as a freewheeling diode in the boost circuit to stabilize the output voltage. This diode has a large voltage difference, resulting in low boost efficiency. In the charging circuit, a PMOS tube is used, which has many power components. Furthermore, two ports must be used, one for charging input and one for boost output, resulting in high costs.

[0005] For a single-port converter, Figure 1The circuit schematic diagram is shown. In standby mode, when a load is connected, the internal load detection function is triggered to determine the load connection and start the boost mode to discharge externally. In conventional technology, the basic principle of load detection of the mobile power converter is to use the relationship between current and voltage in the circuit to determine the on-off state of the load. When the load path is normal, the load current flowing through the resistor R1 will produce a voltage drop, and when the load is disconnected, the voltage drop of the resistor R1 is zero, so the boost / charge detection circuit determines whether the boost circuit needs to work by detecting the voltage drop of the resistor R1 connected in series in the output path. In standby state, the resistor R1 can also be connected in parallel between the drain and source of the PMOS through certain control means, at this time the output voltage is close to the battery voltage, when a load is connected, the load current makes the output voltage be pulled down, and the boost detection circuit detects that the output voltage is lower than a certain threshold, then it is determined that the output terminal has a load connected and enters the boost mode. In some conventional technologies, the resistor R1 can be replaced by the on or sub-threshold impedance of the PMOS as a detection resistor. However, in these detection methods, the detection current passes through the internal resistor, and because the integrated circuit process determines that the internal resistor has a large absolute resistance value deviation distribution, the load current threshold of the energy storage element converter will have a large error, that is, the load detection current threshold is not accurate. SUMMARY

[0006] To solve the above technical problems, the embodiments of the present disclosure provide a converter for an energy storage element.

[0007] At least one converter for an energy storage element of the present disclosure comprises: a charger / load connection port, an energy storage element connection port, a load detection circuit, a body diode control circuit, an NMOS power tube, a PMOS power tube, a logic control circuit, a driving circuit, and a working mode detection circuit, wherein:

[0008] The first terminal of the charger / load connection port is connected to the first electrode of the PMOS power tube, the second electrode of the PMOS power tube is connected to the first electrode of the NMOS power tube and the first terminal of the energy storage element connection port, the second electrode of the NMOS power tube is grounded, and the gate of the NMOS power tube is connected to the second terminal of the driving circuit;

[0009] The first terminal of the logic control circuit is connected to the first terminal of the charger / load connection port, the second terminal of the logic control circuit is connected to the first terminal of the driving circuit, the third terminal of the logic control circuit is connected to the first terminal of the working mode detection circuit, and the fourth terminal of the logic control circuit is connected to the second terminal of the energy storage element connection port;

[0010] The second terminal of the driving circuit is connected to the gate of the NMOS power tube, the third terminal of the driving circuit is connected to the gate of the PMOS power tube, and the fourth terminal of the driving circuit is connected to the second terminal of the working mode detection circuit;

[0011] The third terminal of the operating mode detection circuit is connected to the first terminal of the charger / load connection port, and the fourth terminal of the operating mode detection circuit is connected to the second terminal of the energy storage element connection port; and

[0012] The first terminal of the body diode control circuit is connected to the first terminal of the charger / load connection port, the second terminal of the body diode control circuit is connected to the second terminal of the energy storage element connection port, the third terminal of the body diode control circuit is connected to the substrate of the PMOS power tube, and the fourth terminal of the body diode control circuit is connected to the first terminal of the charger / load connection port through the load detection circuit.

[0013] In one embodiment of the present disclosure, the load detection circuit is a load detection PMOS tube, the first electrode of the load detection PMOS tube is connected to the second terminal of the energy storage element connection port, the second electrode of the load detection PMOS tube is connected to the first terminal of the charger / load connection port, the substrate of the load detection PMOS tube is connected to the fourth terminal of the body diode control circuit, the gate of the load detection PMOS tube is connected to the gate of the current mirror PMOS tube, the first electrode of the current mirror PMOS tube is connected to the second terminal of the energy storage element connection port, and the second electrode of the current mirror PMOS tube is grounded through a bias current source.

[0014] In one embodiment of the present disclosure, the body diode control circuit includes a comparator, an inverter, a first transmission gate, a second transmission gate, and a third transmission gate. The non-inverting input of the comparator is connected to the first terminal of the charger / load connection port, the inverting input is connected to the second terminal of the energy storage element connection port, the output of the comparator is respectively connected to the input of the inverter, the P terminal of the first transmission gate, the N terminal of the second transmission gate, and the P terminal of the third transmission gate, the output of the inverter is connected to the N terminal of the first transmission gate, the P terminal of the second transmission gate, and the N terminal of the third transmission gate; the input of the first transmission gate is connected to the first electrode of the PMOS power tube, the input of the second transmission gate is connected to the second electrode of the PMOS power tube, and the input of the third transmission gate is connected to the second terminal of the energy storage element connection port; the outputs of the first transmission gate and the second transmission gate are both connected to the substrate of the PMOS power tube; the outputs of the second transmission gate and the outputs of the third transmission gate are both connected to the substrate of the load detection PMOS tube.

[0015] In one embodiment of the present disclosure, the converter further includes a filter capacitor connected between the first terminal of the charger / load connection port and the ground.

[0016] In one embodiment of the present disclosure, the converter has a standby mode, a charging mode, and a boost mode, wherein:

[0017] When a first voltage at a first terminal of the charger / load connection port is close to a second voltage at a second terminal of the energy storage element connection port, the converter is in a standby mode;

[0018] When the converter is in the standby mode, the converter enters the boost mode in a case where the first voltage is pulled down; and

[0019] When the converter is in the standby mode, the converter enters the charging mode in a case where the first voltage is pulled up.

[0020] In one embodiment of the present disclosure, when the converter is in the charging mode, when the first voltage drops to be close to the second voltage, the converter enters the standby mode.

[0021] In one embodiment of the present disclosure, when the converter is in the boost mode, if the load current detected by the load detection PMOS tube is less than a current threshold, the converter delays the first time to enter the standby mode.

[0022] In one embodiment of the present disclosure, the current threshold is within a range of 5 mA to 20 mA, and the first time is within a range of 4 s to 8 s.

[0023] At least one embodiment of the present disclosure provides a method for controlling an operating mode of a converter, the method comprising:

[0024] When detecting that a first voltage at a first terminal of the charger / load connection port and a second voltage at a second terminal of the energy storage element connection port are close to each other, placing the converter in a standby mode;

[0025] In the standby mode, when the first voltage is greater than a first voltage threshold, the converter is switched to the charging mode; when the first voltage is lower than a second voltage threshold, the converter is switched to the boost mode;

[0026] In the charging mode, when the first voltage drops to a level close to the second voltage, switching the converter to the standby mode; and

[0027] In the boost mode, when the load current is less than the current threshold, the converter is switched to the standby mode after a first delay.

[0028] At least one embodiment of the present disclosure provides a power supply system, comprising the above-mentioned converter, an energy storage element, and an inductor, wherein the inductor is connected between a first terminal and a second terminal of the energy storage element connection port of the converter, and the positive electrode of the energy storage element is connected to the second terminal of the energy storage element connection port of the converter.

[0029] In a converter for energy storage elements according to an embodiment of the present disclosure, the body diode control circuit has simple logic, simplifies the connection relationship between system modules, and is easy to control. This ensures that the substrate of the PMOS power transistor and the substrate of the load detection PMOS transistor can be connected to the higher voltage end with a fast response speed and are not easily interfered with. At the same time, the body diode control circuit has a boost process detection function. It connects the substrate of the PMOS power transistor to its second electrode only when the first voltage of the first terminal of the charger / load connection port is greater than the first voltage of the first terminal of the charger / load connection port. This avoids the body diode control circuit switching the substrate of the PMOS power transistor from connecting to its second electrode to its first electrode when the converter just enters boost mode and the output voltage is still low, thereby avoiding leakage problems. At the same time, the introduction of the load detection PMOS transistor in the converter allows current to flow only within the load detection PMOS transistor without passing through an external inductor, reducing the influence of inductive elements on the current and improving load detection accuracy. At the same time, the current generated by the current mirror is easy to control and does not require an internal resistor.

[0030] In the method for controlling the operating mode of the above-mentioned converter according to an embodiment of the present disclosure, the operating mode of the converter is determined only by comparing the relationship between the first voltage of the first terminal of the charger / load connection port and the second voltage of the second terminal of the energy storage element connection port, as well as the relationship between the load current and the threshold current. The logical relationship is simple and the implementation difficulty is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The schematic diagram of a single-port mobile power converter in conventional technology is shown;

[0032] Figure 2 A schematic diagram of a circuit structure of a converter for an energy storage element according to an embodiment of the present disclosure is shown; and

[0033] Figure 3 FIG. 4 is a schematic diagram showing a circuit structure of a body diode in a converter according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0035] To address the above technical issues, embodiments of the present disclosure provide a high-precision load detection method and a mobile power converter with high-precision auxiliary load detection. This method utilizes a PMOS transistor to generate a fixed pull-up current. When a load is connected and the output voltage drops to a certain threshold, the load is detected and the voltage boost is initiated. This detection method utilizes a current mirror that generates currents that are largely internal to the chip, eliminating the need for external inductors. Furthermore, the current generated by the current mirror is easily controllable, resulting in superior accuracy and eliminating the need for internal resistors.

[0036] At least one embodiment of the present disclosure provides a converter for an energy storage element, comprising: a charger / load connection port, an energy storage element connection port, a load detection circuit, an NMOS power tube, a PMOS power tube, a logic control circuit, a drive circuit, an operating mode detection circuit, and a body diode control circuit.

[0037] Figure 2 FIG. 1 shows a schematic diagram of a circuit principle of a converter for an energy storage element according to an embodiment of the present disclosure. Figure 2 As shown, the converter includes a charger / load connection port VO / VIN, an energy storage element connection port, a load detection circuit 10, a body diode control circuit 9, an NMOS power tube 3, a PMOS power tube 4, a logic control circuit 6, a drive circuit 7, and an operating mode detection circuit 8.

[0038] like Figure 2 As shown in the figure, the connection relationship between the various components of the converter is as follows:

[0039] The first terminal of the charger / load connection port is connected to the first electrode 41 of the PMOS power tube 4, the second electrode 42 of the PMOS power tube 4 is connected to the first electrode 31 of the NMOS power tube 3 and the first terminal 101 of the energy storage element connection port, the second electrode 32 of the NMOS power tube 3 is grounded, and the gate of the NMOS power tube 3 is connected to the second terminal 72 of the drive circuit 7;

[0040] A first terminal 61 of the logic control circuit 6 is connected to a first terminal of the charger / load connection port VO / VIN, a second terminal 62 of the logic control circuit 6 is connected to a first terminal 71 of the drive circuit 7, a third terminal 63 of the logic control circuit 6 is connected to a first terminal 81 of the working mode detection circuit 8, and a fourth terminal 64 of the logic control circuit 6 is connected to a second terminal 102 of the energy storage element connection port;

[0041] The second terminal 72 of the driving circuit 7 is connected to the gate 33 of the NMOS power transistor 3, the third terminal 73 of the driving circuit 7 is connected to the gate 43 of the PMOS power transistor 4, and the fourth terminal 74 of the driving circuit 7 is connected to the second terminal 82 of the working mode detection circuit 8;

[0042] The third terminal 83 of the working mode detection circuit 8 is connected to the first terminal of the charger / load connection port VO / VIN, and the fourth terminal 84 of the working mode detection circuit 8 is connected to the second terminal 102 of the energy storage element connection port; and

[0043] The first terminal 91 of the body diode control circuit 9 is connected to the first terminal of the charger / load connection port VO / VIN, the second terminal 92 of the body diode control circuit 9 is connected to the second terminal 102 of the energy storage element connection port, the third terminal 93 of the body diode control circuit 9 is connected to the substrate Sub1 of the PMOS power tube 3, and the fourth terminal 94 of the body diode control circuit 9 is connected to the first terminal of the charger / load connection port VO / VIN through the load detection circuit 10.

[0044] In one embodiment of the present disclosure, Figure 2 As shown, the load detection circuit comprises a load detection PMOS transistor. The first electrode of the load detection PMOS transistor is connected to the second terminal of the energy storage element connection port, the second electrode of the load detection PMOS transistor is connected to the first terminal of the charger / load connection port, the substrate of the load detection PMOS transistor is connected to the fourth terminal of the body diode control circuit, and the gate of the load detection PMOS transistor is connected to the gate of the current mirror PMOS transistor. The first electrode of the current mirror PMOS transistor is connected to the second terminal of the energy storage element connection port, and the second electrode of the current mirror PMOS transistor is grounded via a bias current source. The gate of the load detection PMOS transistor is connected to the gate of the current mirror PMOS transistor, allowing the load detection PMOS transistor to generate a fixed pull-up current, i.e., a load detection current threshold, for example, 20μA. When the load is removed and the boost function is shut down and enters standby mode, the load detection PMOS transistor pulls the boost output voltage up to the energy storage element voltage. When a load current appears at the charger / load connection port VO / VIN, if the load current is greater than the current generated by the load detection PMOS tube, the voltage at the boost output end will be pulled down. When it is pulled down to a certain threshold, it is determined that the external load current is indeed generated by the external device, and the boost function is then turned on.

[0045] Introducing a load detection PMOS tube into the converter used for energy storage elements allows the current to flow inside the load detection PMOS tube instead of through an external inductor, reducing the influence of the inductive element on the current and improving the load detection accuracy. At the same time, the current generated by the current mirror is easy to control and does not require an internal resistor.

[0046] In one embodiment of the present disclosure, the first terminal 91 and the second terminal 92 of the body diode control circuit 9 serve as input terminals, connected to the first terminal of the charger / load connection port VO / VIN and the second terminal 102 of the energy storage element connection port, respectively. That is, the first voltage of the first terminal of the charger / load connection port VO / VIN and the second voltage of the second terminal of the energy storage element connection port (the voltage of the positive electrode of the energy storage element when the energy storage element is connected) serve as inputs to the body diode control circuit 9. The third terminal 93 of the body diode control circuit 9 is connected to the substrate Sub1 of the PMOS power transistor 4, and the fourth terminal 94 of the body diode control circuit 9 is connected to the substrate Sub2 of the load detection PMOS transistor. The output of the body diode control circuit 9 is used to control the PMOS power transistor 4 and the load detection circuit 10.

[0047] The following will refer to Figure 3 The connection relationship between the body diode control circuit 9 and the first terminal of the charger / load connection port VO / VIN, the second terminal of the energy storage element connection port, the substrate Sub1 of the PMOS power transistor 4, and the substrate Sub2 of the load detection PMOS transistor is described.

[0048] Figure 3 A schematic structural diagram of a body diode control circuit in a converter for an energy storage element according to an embodiment of the present disclosure is shown.

[0049] like Figure 3 As shown, the first input terminal and the second input terminal of the body diode control circuit are respectively connected to the first terminal of the charger / load connection port VO / VIN and the second terminal of the energy storage element connection port, and the first output terminal and the second output terminal are respectively connected to the substrate Sub1 of the PMOS power tube 4 and the substrate Sub2 of the load detection PMOS tube 10.

[0050] The body diode control circuit 9 includes a comparator 901, an inverter 902, a first transmission gate 903, a second transmission gate 904, and a third transmission gate 905. The non-inverting input of the comparator 901 is connected to the first terminal of the charger / load connection port VO / VIN, and the inverting input is connected to the second terminal of the energy storage element connection port. That is, the voltage at the non-inverting input of the comparator 901 is the first voltage at the first terminal of the charger / load connection port VO / VIN, and the voltage at the inverting input of the comparator 901 is the second voltage at the second terminal of the energy storage element connection port. The output end of the comparator 901 is respectively connected to the input end of the inverter 902, the P end of the first transmission gate 903, the N end of the second transmission gate 902, and the P end of the third transmission gate 903; the output end of the inverter 902 is connected to the N end of the first transmission gate 903, the P end of the second transmission gate 904, and the N end of the third transmission gate 905; the input end of the first transmission gate 903 is connected to the first electrode 41 of the PMOS power transistor 4, the input end of the second transmission gate 904 is connected to the second electrode 42 of the PMOS power transistor 4, and the input end of the third transmission gate 905 is connected to the second terminal 102 of the energy storage element connection port; the output ends of the first transmission gate 903 and the second transmission gate 904 are both connected to the substrate Sub1 of the PMOS power transistor 4; the output end of the second transmission gate 904 and the output end of the third transmission gate 905 are both connected to the substrate Sub2 of the load detection PMOS transistor 10.

[0051] In the body diode control circuit 9, a first voltage at the first terminal of the charger / load connection port VO / VIN and a second voltage at the second terminal of the energy storage element connection port are used as inputs of the body diode control circuit 9. By comparing the first voltage and the second voltage, the output structure of the body diode control circuit 9 controls the connection of the substrate of the PMOS power tube 4 and the connection of the substrate of the load detection PMOS tube 10, so that the substrate of the PMOS power tube 4 is connected to the electrode with a higher voltage among its first electrode 41 and second electrode 42, and the substrate of the load detection PMOS tube 10 is connected to the terminal with a higher voltage among the first terminal of the charger / load connection port VO / VIN and the second terminal of the energy storage element connection port.

[0052] The body diode control circuit has simple logic, simplifies the connections between system modules, and is easy to control. This ensures that the substrate of the PMOS power transistor 4 and the substrate of the load detection PMOS transistor 10 can be connected to the higher voltage end with a fast response speed and are not easily affected by interference.

[0053] The body diode control circuit has a boost process detection function. When the converter enters boost mode, the output voltage begins to rise, and the body diode control circuit begins to operate. When it detects that the first voltage at the first terminal of the charger / load connection port VO / VIN is less than the second voltage at the second terminal of the energy storage element connection port, the body diode control circuit connects the substrate of the PMOS power transistor 4 to its second electrode 42 (i.e., the electrode connected to the energy storage element connection port). When it detects that the first voltage is greater than the second voltage, the body diode control circuit connects the substrate of the PMOS power transistor 4 to its first electrode 41 (i.e., the electrode connected to the first terminal of the charger / load connection port VO / VIN). This prevents leakage caused by the body diode control circuit switching the substrate of the PMOS power transistor from its second electrode to its first electrode when the converter just enters boost mode and the output voltage is still low.

[0054] In one embodiment of the present disclosure, Figure 2 As shown, the converter further includes a filter capacitor 5 connected between a first terminal of the charger / load connection port VO / VIN and ground. Filter capacitor 5 is configured to reduce the amplitude of the charger output ripple during charging, ensuring proper circuit operation. Filter capacitor 5 is also configured to stabilize the boosted output voltage during boosted output.

[0055] In one embodiment of the present disclosure, an external load or charger is connected to the charger / load connection port VO / VIN, an inductor 2 is connected between the first terminal 101 and the second terminal 102 of the energy storage element connection port, the first terminal of the energy storage element 1 is connected to the second terminal 102 of the energy storage element connection port, and the second terminal of the energy storage element is grounded. The load or charger, the energy storage element and the inductor are connected to the converter in the following manner: Figure 2 Energy storage element 1 can be a lithium battery, nickel-cadmium battery, lead-acid battery, nickel-metal hydride battery, etc. When the converter is in standby mode, the energy storage element is neither charged nor discharged. When the converter is in the charging input state, energy storage element 1 is charged, and when the converter is in the boost output state, energy storage element 1 is discharged.

[0056] The logic control circuit 6 is configured to monitor the operating state of the converter and control the enabling of the driving circuit 7 and the operating mode detection circuit 8 based on the operating state.

[0057] The logic control circuit 6 is configured to monitor the system operating state, perform logical operations on the detection results of system parameters of various operating states, such as load current, output voltage, energy storage element voltage, etc., and realize the regulation of the system operating state by controlling the enablement of the boost / charge drive circuit and the boost / charge mode detection circuit. For example, the logic control circuit 6 is configured to detect and monitor the load current in the boost mode. When the current at the charger / load connection port VO / VIN is too large, it will stop the operation of the drive circuit and put the converter into a standby state to prevent the energy storage element from being in a high current output state and damaging the energy storage element. For another example, in the charging mode, the logic control circuit 6 is configured to detect the second voltage of the second terminal of the energy storage element connection port. When the second voltage is greater than a certain voltage threshold, it is determined that the energy storage element has been in an overshoot state, and the converter is forced to enter a standby state and no longer charge the energy storage element.

[0058] After the converter is connected to the energy storage element 1 at the energy storage element connection port, if the charger / load connection port VO / VIN is not connected to a charger or a load, that is, the converter is in standby mode, such as Figure 2 As shown, the first voltage of the first terminal of the charger / load connection port VO / VIN is pulled up to a voltage close to the first terminal of the energy storage element 1 (i.e., the second voltage of the second terminal of the energy storage element interface) through the load detection circuit (i.e., the load detection P-type MOS transistor). The first voltage and the second voltage are close, and the working mode detection circuit 8 determines that the converter is in standby mode.

[0059] When a charger is connected to the charger / load connection port VO / VIN and the charger's output voltage is greater than 4.5V, the logic control circuit detects that the first voltage at the first terminal of the charger / load connection port is greater than the second voltage at the first terminal of the energy storage element. The logic control circuit's state is updated, and the logic control circuit enables the operating mode detection circuit to detect the converter's operating mode. Operating mode detection circuit 7 samples and compares the first and second voltages at this point. Since the first voltage is greater than the second voltage, the operating mode detection circuit determines that the converter has entered charging mode.

[0060] After determining that the converter has entered charging mode, the charger / load connection port VO / VIN serves as a charging input port. The operating mode detection circuit 8 and the logic control circuit 6 send an enable signal to the driver circuit 7, causing it to drive the NMOS power transistor and the PMOS power transistor in charging mode. In charging mode, the driver circuit 7 provides a high level to the gates of the NMOS power transistor 3 and the PMOS power transistor 4, respectively, turning off the NMOS power transistor 3 and turning on the PMOS power transistor 4. Simultaneously, the body diode control circuit 9 connects the substrate of the PMOS power transistor 4 to the first electrode of the PMOS power transistor and the substrate of the load detection PMOS transistor 10 to the first electrode of the PMOS power transistor 4. The first electrode of the PMOS power transistor 4 is connected to the charger / load connection port VO / VIN, allowing the converter to control the charging current through the inductor to charge the energy storage element 1 only by controlling the conduction of the PMOS power transistor 4.

[0061] In charging mode, if the charger is removed or has no voltage output capability, the logic control circuit 6 detects the state change and enables the operating mode detection circuit 8 to detect the operating state of the converter. Since the previous state was the charging state, as long as the first voltage of the first terminal of the charger / load connection port VO / VIN drops to a second voltage close to the second terminal 102 of the energy storage element interface, the converter is determined to enter the standby state. At this time, the body diode control circuit 9 connects the substrate Sub1 of the PMOS power transistor 4 to the second electrode 402 of the PMOS power transistor 4, and at the same time, connects the substrate Sub2 of the load detection PMOS transistor to the second terminal 102 of the energy storage element interface.

[0062] When a load is connected to the charger / load connection port VO / VIN, a load current is generated. If this load current exceeds the current generated by the load detection PMOS transistor (i.e., the load detection current threshold), the voltage at the charger / load connection port VO / VIN will be pulled down. When it drops to a certain threshold (generally 200mV less than the positive voltage of the energy storage element, or 2.4V), the operating mode detection circuit determines that an external load is inserted and enters boost mode. At this time, the logic control circuit and the operating mode detection circuit respectively enable the driver circuit, causing the driver circuit to drive NMOS power transistor 3 and PMOS power transistor 4 in boost mode. That is, MOS power transistor 3 and PMOS power transistor 4 are alternately turned on.

[0063] In boost mode, if the load is removed from the charger / load connection port VO / VIN, the load detection PMOS transistor pulls up the first voltage at the first terminal of the charger / load connection port VO / VIN to the second voltage at the second terminal of the energy storage element connection port. The boost function is disabled, the logic control circuit is reset, and the converter enters standby mode. If a load is connected to the charger / load connection port VO / VIN, the load current draws the first voltage at the first terminal of the charger / load connection port VO / VIN down to a certain threshold, at which point the converter enters boost mode, with the charger / load connection port VO / VIN serving as the boost output port. When the output voltage exceeds the energy storage element voltage, the body diode control circuit 9 connects the substrate Sub1 of the PMOS power transistor 3 to the first terminal of the charger / load connection port VO / VIN and the substrate Sub2 of the load detection PMOS transistor 10 to the first terminal of the charger / load connection port VO / VIN. The energy storage element, inductor, NMOS power transistor, and PMOS power transistor now form a typical synchronous rectification boost circuit, resulting in a stable voltage output at the converter's output port that is higher than the positive voltage of the energy storage element. In boost mode, if the load current is less than the current threshold and is detected by the logic control circuit, the converter enters standby mode after a first delay. The body diode control circuit 9 connects the substrate Sub1 of the PMOS power transistor 4 to the second electrode 42 of the PMOS power transistor 4 and the substrate Sub2 of the load detection PMOS transistor to the second terminal 102 of the energy storage element connection port. The current threshold can range from 5 mA to 20 mA, and the first delay can range from 4 seconds to 8 seconds.

[0064] In an embodiment of the present disclosure, after the converter is connected to the energy storage element, if no load or charger is connected to the charger / load connection port VO / VIN, a first voltage at a first terminal of the charger / load connection port VO / VIN is pulled up by a load detection PMOS transistor to a second voltage at a second terminal of the energy storage element connection port, and the first voltage is approximately equal to the second voltage. At this time, the operating mode of the converter is determined to be standby mode. In standby mode, if the first voltage at the first terminal of the charger / load connection port VO / VIN is pulled down to a certain threshold, that is, the first voltage is less than the second voltage, the operating mode of the converter is determined to be boost mode. In standby mode, if the first voltage at the first terminal of the charger / load connection port VO / VIN is pulled up to a value greater than the second voltage, the operating mode of the converter is determined to be charging mode. In charging mode, if the charger is removed or the charger has no voltage output capability, the first voltage drops to close to the second voltage, and the operating mode of the converter changes to standby mode. In boost mode, if the load is removed, the load current is less than the current threshold, and the operating mode of the converter changes to standby mode.

[0065] In the embodiment of the present disclosure, the operating mode of the converter is determined based on the relationship between the first voltage of the first terminal of the charger / load connection port VO / VIN and the second voltage of the second terminal of the energy storage element connection port, and the load current and the current threshold, simply by comparing the first voltage of the first terminal of the charger / load connection port VO / VIN and the second voltage of the second terminal of the energy storage element connection port, and comparing the load current and the current threshold. This is simple and reliable.

[0066] Accordingly, at least one embodiment of the present disclosure provides a method for determining an operating mode, which is applicable to the converter according to the above embodiments of the present disclosure, and includes:

[0067] detecting a first voltage at a first terminal of the charger / load connection port and a second voltage at a second terminal of the energy storage element connection port, and placing the converter in a standby mode when the first voltage and the second voltage are close to each other;

[0068] In the standby mode, when the first voltage is greater than a first voltage threshold, the converter is switched to the charging mode; when the first voltage is lower than a second voltage threshold, the converter is switched to the boost mode;

[0069] In the charging mode, when the first voltage drops to a level close to the second voltage, switching the converter to the standby mode; and

[0070] In the boost mode, when the load current is less than the current threshold, the converter is switched to the standby mode after a first delay.

[0071] The first voltage threshold may be the output voltage of the charger, the second voltage threshold may be a voltage 200 mV lower than the positive voltage of the energy storage element, the current threshold may range from 5 mA to 20 mA, and the first time may range from 4 s to 8 s.

[0072] In the method for determining the operating mode of a converter suitable for an energy storage element according to an embodiment of the present disclosure, the operating mode of the converter is determined only by comparing the relationship between the first voltage of the first terminal of the charger / load connection port and the second voltage of the second terminal of the energy storage element connection port, as well as the relationship between the load current and the current threshold. The logical relationship is simple and the implementation difficulty is low.

[0073] At least one embodiment of the present disclosure also provides a power supply system, including the above-mentioned converter and energy storage element, the power supply system also including an inductor, the inductor connected between the first terminal and the second terminal of the energy storage element connection port of the converter, and the positive pole of the energy storage element connected to the second terminal of the energy storage element connection port of the converter.

[0074] In the power supply system according to the embodiment of the present disclosure, the operating mode of the converter is determined solely by comparing the relationship between the first voltage of the first terminal of the charger / load connection port VO / VIN and the second voltage of the second terminal of the energy storage element connection port, as well as comparing the relationship between the load current and the current threshold. This logical relationship is simple and reliable, and implementation is easy. Furthermore, the introduction of a load detection PMOS transistor improves load detection accuracy. Furthermore, the connection relationship of the body diode control circuit is simplified, enabling the body diode control circuit to have a boost process detection function, thereby avoiding leakage problems caused by immediately switching the connection relationship of the substrate of the PMOS power transistor when the converter enters the boost mode.

[0075] The above description is only a preferred embodiment of the present disclosure, and the embodiment is not intended to limit the scope of patent protection of the present disclosure. Therefore, any equivalent structural changes made using the description and drawings of the present disclosure should also be included in the scope of protection of the present disclosure.

Claims

1. A converter for an energy storage element, comprising: Charger / load connection port, energy storage element connection port, load detection circuit, body diode control circuit, NMOS power transistor, PMOS power transistor, logic control circuit, drive circuit, operating mode detection circuit, including: The first terminal of the charger / load connection port is connected to the first electrode of the PMOS power tube, the second electrode of the PMOS power tube is connected to the first electrode of the NMOS power tube and the first terminal of the energy storage element connection port, the second electrode of the NMOS power tube is grounded, and the gate of the NMOS power tube is connected to the second terminal of the drive circuit; A first terminal of the logic control circuit is connected to a first terminal of the charger / load connection port, a second terminal of the logic control circuit is connected to a first terminal of the drive circuit, a third terminal of the logic control circuit is connected to a first terminal of the working mode detection circuit, and a fourth terminal of the logic control circuit is connected to a second terminal of the energy storage element connection port; The second terminal of the driving circuit is connected to the gate of the NMOS power tube, the third terminal of the driving circuit is connected to the gate of the PMOS power tube, and the fourth terminal of the driving circuit is connected to the second terminal of the working mode detection circuit; The third terminal of the working mode detection circuit is connected to the first terminal of the charger / load connection port, and the fourth terminal of the working mode detection circuit is connected to the second terminal of the energy storage element connection port; The load detection circuit is a load detection PMOS transistor, wherein a first electrode of the load detection PMOS transistor is connected to the second terminal of the energy storage element connection port, a second electrode of the load detection PMOS transistor is connected to the first terminal of the charger / load connection port, a substrate of the load detection PMOS transistor is connected to the fourth terminal of the body diode control circuit, a gate of the load detection PMOS transistor is connected to the gate of a current mirror PMOS transistor, a first electrode of the current mirror PMOS transistor is connected to the second terminal of the energy storage element connection port, and a second electrode of the current mirror PMOS transistor is grounded via a bias current source; and The first terminal of the body diode control circuit is connected to the first terminal of the charger / load connection port, the second terminal of the body diode control circuit is connected to the second terminal of the energy storage element connection port, the third terminal of the body diode control circuit is connected to the substrate of the PMOS power tube, and the fourth terminal of the body diode control circuit is connected to the first terminal of the charger / load connection port through the load detection circuit; the body diode control circuit includes a comparator, an inverter, a first transmission gate, a second transmission gate and a third transmission gate, the non-inverting input terminal of the comparator is connected to the first terminal of the charger / load connection port, the inverting input terminal is connected to the second terminal of the energy storage element connection port, the comparator The output end is respectively connected to the input end of the inverter, the P end of the first transmission gate, the N end of the second transmission gate, and the P end of the third transmission gate. The output end of the inverter is connected to the N end of the first transmission gate, the P end of the second transmission gate, and the N end of the third transmission gate. The input end of the first transmission gate is connected to the first electrode of the PMOS power tube, the input end of the second transmission gate is connected to the second electrode of the PMOS power tube, and the input end of the third transmission gate is connected to the second terminal of the energy storage element connection port. The output ends of the first transmission gate and the second transmission gate are both connected to the substrate of the PMOS power tube. The output ends of the second transmission gate and the output ends of the third transmission gate are both connected to the substrate of the load detection PMOS tube.

2. The converter according to claim 1, wherein The converter further includes a filter capacitor connected between a first terminal of the charger / load connection port and ground.

3. The converter according to claim 1, wherein The converter has a standby mode, a charging mode and a boost mode, wherein: When a first voltage at a first terminal of the charger / load connection port is close to a second voltage at a second terminal of the energy storage element connection port, the converter is in a standby mode; When the converter is in the standby mode, the converter enters the boost mode in a case where the first voltage is pulled down; and When the converter is in the standby mode, the converter enters the charging mode in a case where the first voltage is pulled up.

4. The converter according to claim 3, wherein When the converter is in the charging mode, the converter enters the standby mode in a case where the first voltage drops to be close to the second voltage.

5. The converter according to claim 3, wherein When the converter is in the boost mode, in the case that the load current detected by the load detection PMOS tube is less than the current threshold, the converter delays the first time to enter the standby mode.

6. The converter according to claim 5, wherein The current threshold is in the range of 5 mA to 20 mA, and the first time is in the range of 4 s to 8 s.

7. A method for controlling an operating mode of the converter according to claim 1, the method comprising: When detecting that a first voltage at a first terminal of the charger / load connection port and a second voltage at a second terminal of the energy storage element connection port are close to each other, placing the converter in a standby mode; In the standby mode, when the first voltage is greater than a first voltage threshold, the converter is switched to the charging mode; when the first voltage is lower than a second voltage threshold, the converter is switched to the boost mode; In the charging mode, when the first voltage drops to a level close to the second voltage, switching the converter to the standby mode; as well as In the boost mode, when the load current is less than the current threshold, the converter is switched to the standby mode after a first delay.

8. A power supply system comprising the converter according to claim 1, an energy storage element, and an inductor, wherein the inductor is connected between a first terminal and a second terminal of the energy storage element connection port of the converter, and the positive electrode of the energy storage element is connected to the second terminal of the energy storage element connection port of the converter.

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