Charging control circuit and charging device

Abstract

The application relates to a charging control circuit and a charging device. The charging control circuit comprises an impedance module, a pre-charging switch module and a detection switch module arranged at the output end of a direct-current converter. The impedance module and the pre-charging switch module are connected in series at the output positive pole of the direct-current converter, and the impedance module and the detection switch module are connected in series between the output positive pole and the output negative pole of the direct-current converter. When the detection switch module is closed and the pre-charging switch module is disconnected, the starting voltage detection can be realized through the impedance module and the detection switch module. When the detection switch module is disconnected and the pre-charging switch module is closed, the impedance module and the pre-charging switch module are connected at the output positive pole of the direct-current converter and the output positive pole of the charging device. The impedance module is used as a current-limiting element to pre-charge the electronic device, so that the starting detection function and the pre-charging function share the impedance module, the circuit design is simplified, and the circuit cost is reduced.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, and in particular relates to a charging control circuit and a charging device. Background Technology

[0002] When energy storage devices are used outdoors, they can be recharged by charging equipment (such as a car charger) based on a generator. The generator can be a PV (Photovoltaic) panel or a car alternator. Charging equipment typically has undervoltage (or low light) detection circuitry and pre-charge function circuitry, making the circuitry complex and costly. Utility Model Content

[0003] The purpose of this application is to provide a charging control circuit and a charging device, which aims to solve the problems of complex circuits and high costs in existing charging devices.

[0004] In a first aspect, embodiments of this application provide a charging control circuit applied to a charging device, the charging device being used to charge an electronic device, comprising:

[0005] An impedance module, the first end of which is connected to the positive output of the DC-DC converter of the charging device;

[0006] A pre-charge switch module is connected to the second terminal of the impedance module and the positive output terminal of the charging device;

[0007] A detection switch module, wherein the first terminal of the detection switch module is connected to the second terminal of the impedance module, and the second terminal of the detection switch module is connected to the negative output terminal of the DC-DC converter;

[0008] The control module is connected to the pre-charge switch module, the detection switch module, and the positive output of the DC-DC converter. When the charging device is detected to be connected to the power generation device, the control module controls the detection switch module to close. When the detection switch module is closed and the output voltage of the DC-DC converter is greater than or equal to the start-up voltage threshold, the control module controls the detection switch module to open and controls the pre-charge switch module to close to perform a pre-charge operation on the electronic device.

[0009] In some embodiments, the control module is further configured to control the detection switch module to open and control the precharge switch module to remain open when the detection switch module is closed and the output voltage is less than the start-up voltage threshold.

[0010] In some embodiments, the charging control circuit further includes a main charging switch module, which is connected between the positive output terminal of the DC converter and the positive output terminal of the charging device.

[0011] In some embodiments, the control module is further configured to open the pre-charge switch module after a preset time of closing, and to close the main charge switch module.

[0012] In some embodiments, the control module is further configured to control the main charging switch module to remain open when the detection switch module is closed and the output voltage is less than the start-up voltage threshold.

[0013] In some embodiments, the detection switch module includes at least one controllable switch connected between the second terminal of the impedance module and the negative output terminal of the DC converter, and the control terminal of the controllable switch is connected to the control module.

[0014] In some embodiments, the controllable switch includes a MOSFET connected in series between the second terminal of the impedance module and the negative output terminal of the DC-DC converter, and the gate of the MOSFET constitutes the control terminal of the controllable switch.

[0015] In some embodiments, the impedance module includes a first resistor, a first end of which is connected to a first end of the impedance module, and a second end of which is connected to a second end of the impedance module.

[0016] In some embodiments, a second resistor is further included, the first end of which is connected to the positive output terminal of the DC-DC converter, and the second end of which is connected to the first terminal of the impedance module and the main charging switch module, respectively.

[0017] Secondly, embodiments of this application also provide a charging device, including a DC converter and a charging control circuit as described above, wherein the charging control circuit is connected between the DC converter and the output terminal of the charging device.

[0018] The beneficial effects of this application embodiment compared with related technologies are as follows: The charging control circuit includes an impedance module, a pre-charge switch module, and a detection switch module disposed at the output of the DC-DC converter. The impedance module and the pre-charge switch module are connected in series at the positive output terminal of the DC-DC converter, and the impedance module and the detection switch module are connected in series between the positive output terminal and the negative output terminal of the DC-DC converter. When the detection switch module is closed and the pre-charge switch module is open, the start-up voltage can be detected through the impedance module and the detection switch module. When the detection switch module is open and the pre-charge switch module is closed, the impedance module and the pre-charge switch module are connected between the positive output terminal of the DC-DC converter and the positive output terminal of the charging device. The impedance module is reused as a current-limiting element to pre-charge the electronic device, so that the start-up detection function and the pre-charge function reuse the impedance module, simplifying the circuit design and reducing the circuit cost. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a charging device provided in an embodiment of this application.

[0020] Figure 2 A circuit diagram of a charging control circuit provided in an embodiment of this application. Detailed Implementation

[0021] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0022] It should be noted that when a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to that other component.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0024] This application provides a charging control circuit 120, applied to a charging device 100, for charging an electronic device 200.

[0025] Please refer to Figure 1 For example, the charging device 100 includes an input terminal, an output terminal, and a DC-DC converter 110. The DC-DC converter 110 is connected between the input and output terminals of the charging device 100 and can be used for photovoltaic maximum power point tracking (MPPT) and buck-boost conversion. The input terminal of the charging device 100 is used to connect to power generation equipment such as PV panels or a vehicle generator. The electronic device 200 is, for example, an energy storage device or other electric device requiring power. A charging control circuit 120 is connected between the DC-DC converter 110 and the output terminal of the charging device 100. The charging control circuit 120 includes an impedance module 121, a pre-charge switch module 122, a detection switch module 123, and a control module 124.

[0026] The first terminal of impedance module 121 is connected to the positive output V+ of DC-DC converter 110 of charging device 100. Pre-charge switch module 122 is connected to the second terminal of impedance module 121 and the positive output Vout+ of charging device 100. The first terminal of detection switch module 123 is connected to the second terminal of impedance module 121, and the second terminal of detection switch module 123 is connected to the negative output V- of DC-DC converter 110. Control module 124 is connected to pre-charge switch module 122, detection switch module 123, and the positive output V+ of DC-DC converter 110. Control module 124 controls detection switch module 123 to close when charging device 100 is detected to be connected to power generation equipment. When detection switch module 123 is closed and the output voltage of DC-DC converter 110 is greater than or equal to the start-up voltage threshold, control detection switch module 123 to open and control pre-charge switch module 122 to close to perform pre-charge operation on electronic device 200.

[0027] When the detection switch module 123 is closed and the pre-charge switch module 122 is open, the impedance module 121 and the detection switch module 123 are connected between the positive output V+ and the negative output V- of the DC-DC converter 110. The control module 124 can determine whether the power generation voltage of the power generation device has reached the start-up voltage threshold of the electronic device 200 by detecting the output voltage of the DC-DC converter 110. In some scenarios, such as when the power generation device is a photovoltaic panel, this voltage detection function completes the low-light detection function of the charging device 100; in other scenarios, it can be understood as an undervoltage detection function or a start-up voltage detection function. When the detection switch module 123 is open and the pre-charge switch module 122 is closed, the impedance module 121 and the pre-charge switch module 122 are connected between the positive output V+ of the DC-DC converter 110 and the positive output Vout+ of the charging device 100. The impedance module 121 is reused as a current limiting element to pre-charge the electronic device 200, so that the low-light detection function and the pre-charge function reuse the impedance module 121, simplifying the circuit design and reducing the circuit cost.

[0028] In some embodiments, the control module 124 includes a controller that can be connected to the positive output V+ of the DC-DC converter 110 via its sampling port, such as an ADC (Analog-to-Digital Converter) port, to detect the output voltage of the DC-DC converter 110 in order to determine whether the power generation voltage of the power generation device meets the charging requirements.

[0029] In some embodiments, the charging control circuit 120 may also be provided with a sampling circuit, such as a differential amplifier circuit or a voltage divider circuit, connected to the positive output terminal V+ of the DC converter 110, for detecting the output current, output voltage, etc. of the DC converter 110.

[0030] When the charging device 100 charges the energy storage device, and the energy storage device is not powered on, if the charging device 100 directly outputs a large voltage to charge the energy storage device, it may cause the DC-DC converter 110 to short-circuit due to charging the input capacitor of the energy storage device. Therefore, when the energy storage device is not powered on, the input capacitor of the energy storage device can be pre-charged through the pre-charging circuit formed by the impedance module 121 and the pre-charging switch module 122 to activate the energy storage device and prevent short circuit. In addition, in order to prevent the output power of the DC-DC converter 110 (i.e., the power generation power of the generator) from being too low, resulting in insufficient power supplied by the DC-DC converter 110 to the energy storage device system, the charging control circuit 120 also adds weak light detection.

[0031] In some embodiments, the control module 124 is further configured to control the detection switch module 123 to open and control the pre-charge switch module 122 to remain open when the detection switch module 123 is closed and the output voltage is less than the start-up voltage threshold. After the detection switch module 123 is closed, the output voltage of the DC-DC converter 110 is less than the start-up voltage threshold (e.g., 23V), which means that, for example, the PV panel is in a weak light state, the generated energy is insufficient to maintain the voltage and current of the impedance module 121, let alone meet the charging needs of the electronic device 200. Therefore, the detection switch module 123 is controlled to open and the pre-charge switch module 122 is controlled to remain open, thereby preventing the power supplied to the electronic device 200 from being insufficient for the inverter to consume.

[0032] Please also refer to Figure 1 as well as Figure 2 In some embodiments, the charging control circuit 120 further includes a main charging switch module 125, which is connected between the positive output V+ of the DC-DC converter 110 and the positive output Vout+ of the charging device 100. The main charging switch module 125 includes at least one MOSFET Q1.

[0033] In some cases, if the output voltage of the DC-DC converter 110 is detected to be greater than or equal to the start-up voltage threshold (e.g., 23V), the detection switch module 123 is opened, and then the output voltage of the DC-DC converter 110 is raised to the charging voltage (e.g., above 50V). The pre-charge switch module 122 is then closed, and the output voltage charges the input capacitor of the energy storage device through the impedance module 121. Therefore, in some embodiments, the control module 124 is also used to open the pre-charge switch module 122 after a preset time (e.g., 1.2s) and close the main charging switch module 125, allowing the DC-DC converter 110 to charge the energy storage device normally based on the power generation equipment.

[0034] It is understandable that the preset duration can be determined based on the charging voltage and the input capacitance and activation voltage of the energy storage device. For example, the input capacitance of the energy storage device is generally a maximum of 14.4mF, while the charging voltage is 50V, the activation voltage is 40V, and the RC time constant is 0.72. Therefore, it takes about 1.2s for the input capacitance of the energy storage device to charge to 40V, so the preset duration can be set to 1.2s.

[0035] In some embodiments, the control module 124 is further configured to control the main charging switch module 125 to remain open when the detection switch module 123 is closed and the output voltage is less than the start-up voltage threshold. As described above, if the output voltage of the DC-DC converter 110 is less than the start-up voltage threshold, it indicates that the generation voltage cannot meet the charging requirements of the electronic device 200, and the detection switch module 123, the pre-charge switch module 122, and the main charging switch module 125 are controlled to remain open. This prevents a sudden increase in the output voltage of the DC-DC converter 110 from triggering a short circuit.

[0036] In some embodiments, the precharge switch module 122 includes at least one MOSFET Q2. Exemplarily, the MOSFET Q2 is a P-channel MOSFET. In other embodiments, the precharge switch module 122 may also be configured as an N-channel MOSFET.

[0037] In some embodiments, the detection switch module 123 includes at least one controllable switch connected between the second terminal of the impedance module 121 and the negative output terminal V- of the DC-DC converter 110, and the control terminal of the controllable switch is connected to the control module 124. The controllable switch is, for example, a semiconductor transistor or a relay. In some embodiments, the controllable switch includes a MOSFET connected in series between the second terminal of the impedance module 121 and the negative output terminal V- of the DC-DC converter 110, and the gate of the MOSFET constitutes the control terminal of the controllable switch. For example, the detection switch module 123 includes two N-channel MOSFETs Q3 and Q4 connected in series. In other embodiments, the controllable switch can also be a P-channel MOSFET. This application does not limit the selection of the controllable switch, as long as it can be compatible with the control logic of this application.

[0038] In some embodiments, the impedance module 121 includes a first resistor R1, with a first end of the first resistor R1 connected to a first end of the impedance module 121 and a second end of the first resistor R1 connected to a second end of the impedance module 121. For example, the first resistor R1 is a metal film resistor. It is understood that this application does not impose restrictions on the selection of the first resistor R1, as long as it can be compatible with the control logic of this application.

[0039] In some embodiments, the charging control circuit 120 further includes a second resistor R2. The first end of the second resistor R2 is connected to the positive output V+ of the DC-DC converter 110, and the second end of the second resistor R2 is connected to the first end of the impedance module 121 and the main charging switch module 125, respectively. The second resistor R2 can serve as a sampling resistor for sampling the output of the DC-DC converter 110.

[0040] On the other hand, this application embodiment also provides a charging device 100, which includes a DC converter 110 and a charging control circuit 120 as provided in any of the above embodiments. The charging control circuit 120 is connected between the DC converter 110 and the output terminal of the charging device 100.

[0041] The aforementioned charging device 100, when connected to a PV panel input, can activate and charge the energy storage device under conditions of non-weak light and non-short circuit. Furthermore, the weak light detection time can be controlled to approximately 200ms, ensuring that even if a short circuit is triggered in the energy storage device during weak light input, the impedance module 121 composed of metal film resistors can withstand voltage stress.

[0042] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A charging control circuit, applied to a charging device for charging electronic devices, characterized in that, include: An impedance module, the first end of which is connected to the positive output of the DC-DC converter of the charging device; A pre-charge switch module is connected to the second terminal of the impedance module and the positive output terminal of the charging device; A detection switch module, wherein the first terminal of the detection switch module is connected to the second terminal of the impedance module, and the second terminal of the detection switch module is connected to the negative output terminal of the DC-DC converter; The control module is connected to the pre-charge switch module, the detection switch module, and the positive output of the DC-DC converter. It is used to control the detection switch module to close when the charging device is detected to be connected to the power generation device. The control module is also used to control the detection switch module to open and the pre-charge switch module to close to perform a pre-charge operation on the electronic device when the detection switch module is closed and the output voltage of the DC-DC converter is greater than or equal to the start-up voltage threshold.

2. The charging control circuit according to claim 1, characterized in that, The control module is also configured to control the detection switch module to open when the detection switch module is closed and the output voltage is less than the start-up voltage threshold, and to control the pre-charge switch module to remain open.

3. The charging control circuit according to claim 1, characterized in that, The charging control circuit also includes a main charging switch module, which is connected between the positive output terminal of the DC converter and the positive output terminal of the charging device.

4. The charging control circuit according to claim 3, characterized in that, The control module is also used to control the pre-charge switch module to close for a preset time and then open it, and to control the main charge switch module to close.

5. The charging control circuit according to claim 4, characterized in that, The control module is also configured to control the main charging switch module to remain open when the detection switch module is closed and the output voltage is less than the start-up voltage threshold.

6. The charging control circuit according to any one of claims 1 to 5, characterized in that, The detection switch module includes at least one controllable switch, which is connected between the second terminal of the impedance module and the negative output terminal of the DC converter, and the control terminal of the controllable switch is connected to the control module.

7. The charging control circuit according to claim 6, characterized in that, The controllable switch includes a MOSFET, which is connected in series between the second terminal of the impedance module and the negative output terminal of the DC-DC converter. The gate of the MOSFET constitutes the control terminal of the controllable switch.

8. The charging control circuit according to any one of claims 1 to 5, characterized in that, The impedance module includes a first resistor, a first end of which is connected to a first end of the impedance module, and a second end of which is connected to a second end of the impedance module.

9. The charging control circuit according to any one of claims 1 to 5, characterized in that, It also includes a second resistor, the first end of which is connected to the positive output terminal of the DC-DC converter, and the second end of which is connected to the first terminal of the impedance module and the main charging switch module, respectively.

10. A charging device, characterized in that, It includes a DC-DC converter and a charging control circuit as described in any one of claims 1 to 9, wherein the charging control circuit is connected between the DC-DC converter and the output terminal of the charging device.

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