A surge current suppression circuit

Abstract

The application provides a surge current suppression circuit applied to a switching DC boost circuit, the switching DC boost circuit comprising a switching DC boost chip, the switching DC boost chip comprising a switching pin and a feedback pin, characterized in that the surge current suppression circuit comprises a feedback suppression module: the feedback suppression module comprising a first voltage dividing resistor and a current limiting resistor; an output end of the switching DC boost circuit is connected with the feedback pin through the first voltage dividing resistor; an input end of the current limiting resistor is connected with an input end of the switching DC boost circuit, and an output end of the current limiting resistor is connected with the feedback pin. The feedback pin can feed back a signal with a surge current to the input end, so that a feedback suppression effect is achieved. Meanwhile, the surge current suppression circuit can also collect an output voltage of the switching DC boost circuit, and feed back and suppress the surge current.

Description

Technical Field

[0001] This invention relates to the field of switching DC boost circuits, and more specifically to a surge current suppression circuit. Background Technology

[0002] A BOOST circuit is a type of switching DC-DC boost circuit that can convert DC power into a fixed or adjustable DC voltage. It is also known as a DC-DC converter and achieves the purpose of boosting voltage by storing and discharging energy through the inductor of the switching controller.

[0003] In existing BOOST circuits, to suppress inrush current, a BOOST chip with a dedicated enable control pin is selected. This chip is not operational by default upon power-up. The BOOST chip is enabled via a pull-up resistor from the microcontroller, or by using a weak internal pull-up resistor connected to the chip and an external pull-down resistor, followed by microcontroller enable. This approach places requirements on chip selection; a BOOST chip with an enable control pin must be used, and this pin must support logic level input. Furthermore, the timing of the control signal and the BOOST chip input must be considered. Therefore, existing solutions have significant limitations and increase chip cost. Summary of the Invention

[0004] This application provides a surge current suppression circuit to at least solve the technical problems existing in the related art, which require the selection of a BOOST chip with an enable control pin, and the pin needs to support logic level input, while also considering the timing problem between the control signal and the BOOST chip input.

[0005] According to one aspect of the embodiments of this application, a surge current suppression circuit is provided, applied to a switching DC-DC boost circuit. The switching DC-DC boost circuit includes a switching DC-DC boost chip, the switching DC-DC boost chip including a switching pin and a feedback pin. The surge current suppression circuit includes a feedback suppression module: the feedback suppression module includes a first voltage divider resistor and a current-limiting resistor; the output terminal of the switching DC-DC boost circuit is connected to the feedback pin through the first voltage divider resistor; the input terminal of the current-limiting resistor is connected to the boost input terminal of the switching DC-DC boost circuit, and the output terminal of the current-limiting resistor is connected to the feedback pin.

[0006] Optionally, the feedback suppression module further includes a second voltage divider resistor, the input terminal of which is connected to the output terminal of the first voltage divider resistor, and the output terminal of the second voltage divider resistor is grounded.

[0007] Optionally, it also includes a microcontroller and an auxiliary acquisition module. The enable terminal of the auxiliary acquisition module is connected to the first pin of the microcontroller, the input terminal of the auxiliary acquisition module is connected to the output terminal of the current-limiting resistor, and the output terminal of the auxiliary acquisition module is grounded. After the surge current disappears, the first pin of the microcontroller outputs a control signal to control the enable terminal of the auxiliary acquisition module to ground the output terminal of the current-limiting resistor, so that the feedback pin acquires the output voltage of the switching DC boost circuit.

[0008] Optionally, the auxiliary acquisition module includes an enable unit, a first auxiliary resistor, and a second auxiliary resistor; the input terminal of the enable unit is connected to the output terminal of the current-limiting resistor, the output terminal of the enable unit is grounded, and the enable terminal of the enable unit is connected to the first pin of the microcontroller through the first auxiliary resistor; the input terminal of the second auxiliary resistor is connected to the output terminal of the first auxiliary resistor, and the output terminal of the second auxiliary resistor is grounded.

[0009] Optionally, the enabling unit includes a first field-effect transistor.

[0010] Optionally, the auxiliary acquisition module further includes a first diode, the anode of which is connected to the output terminal of the current-limiting resistor, and the cathode of which is connected to the output terminal of the first voltage-dividing resistor.

[0011] Optionally, the surge current suppression circuit further includes a power-on module, the enable terminal of which is connected to the second pin of the microcontroller, the input terminal of which is connected to the boost input terminal of the switching DC boost circuit, and the output terminal of which is grounded.

[0012] Optionally, the power-on module includes a second field-effect transistor (FET) and a third FET; the enable terminal of the second FET is connected to the second pin of the microcontroller, the output terminal of the second FET is grounded, and the input terminal of the second FET is connected to the input terminal of the third FET; the output terminal of the third FET is connected to the switch pin and the boost input terminal of the switch DC boost circuit, respectively, and the enable terminal of the third FET is connected to the input terminal of the second FET.

[0013] Optionally, the switching DC-DC boost circuit includes a second diode, the anode of which is connected to the output terminal of the third field-effect transistor, and the cathode of which is connected to the switch pin and the boost input terminal of the switching DC-DC boost circuit.

[0014] Optionally, the power-on module may further include multiple power-on resistors.

[0015] This application provides a surge current suppression circuit applied to a switching DC-DC boost circuit. The switching DC-DC boost circuit includes a switching DC-DC boost chip, which includes a switching pin and a feedback pin. The surge current suppression circuit includes a feedback suppression module: the feedback suppression module includes a first voltage divider resistor and a current-limiting resistor; the output terminal of the switching DC-DC boost circuit is connected to the feedback pin through the first voltage divider resistor; the input terminal of the current-limiting resistor is connected to the boost input terminal of the switching DC-DC boost circuit, and the output terminal of the current-limiting resistor is connected to the feedback pin. This method utilizes the feedback pin of the switching DC-DC boost chip. When the input voltage of the feedback pin is greater than the reference voltage, i.e., when a surge current is generated, the feedback pin can feed back the signal of the surge current to the input terminal, causing the switching DC-DC boost chip to reduce its modulation frequency or duty cycle, thereby reducing the output voltage at the switching DC-DC boost chip and achieving feedback suppression. Simultaneously, the surge current suppression circuit can also acquire the output voltage of the switching DC-DC boost circuit and feed back and suppress the surge current. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a circuit diagram of a surge current suppression circuit according to an embodiment of this application;

[0019] Figure 2 This is a circuit diagram of another surge current suppression circuit according to an embodiment of this application. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] A BOOST circuit is a switching DC-DC boost circuit that converts direct current (DC) into a fixed or adjustable DC voltage. Also known as a DC-DC converter, it achieves voltage boosting through the energy storage and discharge of the inductor in the switching controller. Existing BOOST circuits use BOOST chips with dedicated enable control pins to suppress inrush current. These chips are not active by default upon power-up. The BOOST chip is enabled by a pull-up resistor from the microcontroller, or by using a weak internal pull-up resistor connected to the chip and an external pull-down resistor, followed by microcontroller enable. This approach places requirements on chip selection; it requires a BOOST chip with an enable control pin that supports logic level input. Timing issues between the control signal and the BOOST chip input must also be considered. Therefore, existing solutions have significant limitations and increase chip cost.

[0023] This application provides a surge current suppression circuit, such as... Figure 1-2 As shown, this is applied to a switching DC-DC boost circuit. The switching DC-DC boost circuit includes a switching DC-DC boost chip, which includes a switching pin SW and a feedback pin FB. The surge current suppression circuit includes a feedback suppression module 1, which includes a first voltage divider resistor R1 and a current limiting resistor R5. The output terminal of the switching DC-DC boost circuit is connected to the feedback pin FB through the first voltage divider resistor R1. The input terminal of the current limiting resistor R5 is connected to the boost input terminal of the switching DC-DC boost circuit, and the output terminal of the current limiting resistor R5 is connected to the feedback pin FB.

[0024] Specifically, in the surge current suppression circuit, when the switch pin SW is turned on, the second diode is directly connected to ground; when the switch pin SW is turned off, a voltage boost occurs due to the energy storage effect of the inductor. Therefore, even when the switch pin SW is turned off, a high voltage exists, i.e., a surge current input. Figure 1As shown, the switching DC-DC boost chip is essentially a DC-DC converter chip. It regulates the output voltage through negative feedback by controlling the opening and closing of the switch pin SW and its duty cycle. The feedback pin, used for feedback adjustment, typically uses 1.2V or 0.8V as the reference voltage. This article does not specify a particular voltage; 1.2V will be used as an example throughout. By adjusting the voltage division values ​​of the first and second voltage divider resistors, the output voltage of the switching DC-DC boost circuit can be adjusted. Specifically, if a voltage > 1.2V is detected at the feedback pin FB, the switching DC-DC boost chip will reduce the modulation frequency or duty cycle, thereby reducing the output voltage of the switching DC-DC boost circuit and achieving feedback regulation. The power supply Vin, serving as the boost input for the switching DC-DC boost chip (typically a 24V power input voltage; this application does not limit this, and 24V will be used throughout this description), is also directly connected to the feedback pin via the current-limiting resistor R5. This configuration ensures that the power supply voltage Vin modulated by the switching DC-DC boost circuit and the feedback voltage at the feedback pin FB are generated at the same power-on timing. That is, the input voltage regulated by the switching DC-DC boost circuit and the feedback voltage at the feedback pin FB are generated simultaneously. By adjusting the resistance values ​​of the second voltage divider resistor and the current-limiting resistor R5, the input voltage at the feedback pin can be made greater than 1.2V. This allows the chip's feedback regulation capability to maintain the output voltage of the switching DC-DC boost chip at a low voltage during the moment the controller is powered on, further reducing the charging current. Simultaneously, the voltage is first input to the feedback pin FB through the current-limiting resistor R5, and then the output voltage of the switching DC-DC boost circuit is input to the feedback pin FB, solving the timing problem between the control signal and the BOOST chip input that needs to be considered in the prior art.

[0025] Optionally, the feedback suppression module 1 further includes a second voltage divider resistor R2, the input terminal of which is connected to the output terminal of the first voltage divider resistor R1, and the output terminal is grounded.

[0026] Optionally, it also includes a microcontroller (MCU) and an auxiliary acquisition module 2. The enable terminal of the auxiliary acquisition module 2 is connected to the first pin of the MCU, the input terminal is connected to the output terminal of the current-limiting resistor R5, and the output terminal is grounded. After the surge current disappears, the first pin of the MCU outputs a control signal to control the enable terminal of the auxiliary acquisition module 2 to ground the output terminal of the current-limiting resistor R5, so that the feedback pin FB can acquire the output voltage of the switching DC boost circuit.

[0027] Optionally, the auxiliary acquisition module 2 includes an enable unit, a first auxiliary resistor R3, and a second auxiliary resistor R4; the input terminal of the enable unit is connected to the output terminal of the current limiting resistor R5, and the output terminal is grounded; the enable terminal is connected to the first pin of the microcontroller MCU through the first auxiliary resistor R3; the input terminal of the second auxiliary resistor R4 is connected to the output terminal of the first auxiliary resistor R3, and the output terminal is grounded.

[0028] Specifically, such as Figure 1 As shown in Figure 2, the input terminal of the enable unit is connected to the output terminal of the current-limiting resistor R5, and the output terminal is grounded. The enable terminal is connected to the first pin of the microcontroller MCU (i.e., ...) through the first auxiliary resistor R3. Figure 1 IO_Control and Figure 2 The input terminal of the second auxiliary resistor R4 is connected to the output terminal of the first auxiliary resistor R3, and the output terminal is grounded. After the surge current disappears, the microcontroller MCU can supply power normally, so the first pin of the microcontroller MCU outputs a high-level signal to control the first field-effect transistor to conduct. The power supply output voltage is grounded through the current-limiting resistor R5, so the feedback pin FB no longer collects the power supply output voltage, but normally collects the output voltage of the switching DC boost circuit.

[0029] Optionally, the enabling unit includes a first field-effect transistor Q1.

[0030] It is understood that this application does not limit the specific type of the enabling unit, such as... Figure 1 As shown, this application uses a field-effect transistor.

[0031] Optionally, the auxiliary acquisition module 2 further includes a first diode D1, the anode of which is connected to the output terminal of the current limiting resistor R5, and the cathode of which is connected to the output terminal of the first voltage dividing resistor R1.

[0032] Specifically, the auxiliary acquisition module 2 further includes a first diode D1, the anode of which is connected to the output terminal of the current-limiting resistor R5, and the cathode of which is connected to the output terminal of the first voltage divider resistor R1. This configuration ensures that after the first field-effect transistor Q1 is closed, the current cannot flow from the first voltage divider resistor R1 to ground via the first field-effect transistor Q1, preventing voltage division from causing inaccurate surge current feedback suppression.

[0033] Optionally, the surge current suppression circuit further includes a power-on module 3, the enable terminal of which is connected to the second pin of the microcontroller MCU (i.e., Figure 2 The input terminals are connected to the pins of the output control signal 1, the input terminals are connected to the boost input terminals of the DC boost circuit, and the output terminals are connected to ground.

[0034] Optionally, the power-on module 3 includes a second field-effect transistor Q2 and a third field-effect transistor Q3; the enable terminal of the second field-effect transistor Q2 is connected to the second pin of the microcontroller MCU, the output terminal is grounded, and the input terminal is connected to the input terminal of the third field-effect transistor Q3; the output terminal of the third field-effect transistor Q3 is connected to the switch pin SW and the boost input terminal of the switch DC boost circuit, respectively, and the enable terminal is connected to the input terminal of the second field-effect transistor Q2.

[0035] Specifically, such as Figure 2 As shown, the enable terminal of the second field-effect transistor Q2 is connected to the second pin of the microcontroller MCU, its output terminal is grounded, and its input terminal is connected to the input terminal of the third field-effect transistor Q3. The output terminal of the third field-effect transistor Q3 is connected to the switch pin SW and the boost input terminal of the switching DC-DC boost circuit, respectively, and its enable terminal is connected to the input terminal of the second field-effect transistor Q2. When the power supply starts outputting voltage, the feedback pin FB first receives the power supply voltage divider, and simultaneously, as... Figure 2 As shown, the DC-DC section is powered on. After this section is powered on, the microcontroller (MCU) can be supplied with power normally. The second pin of the MCU outputs a high level, the second MOSFET Q2 turns on, and the third MOSFET Q3 turns on, starting the switching DC-DC boost circuit. This scheme divides the power-on of the entire electronic control system into three stages: first, the power supply is divided at the feedback pin FB; second, the MCU is powered on; and finally, the switching DC-DC boost circuit is powered on, in order to mitigate the inrush current during the power-on of the entire system.

[0036] Optionally, the switching DC boost circuit includes a second diode D2, the anode of the second diode D2 is connected to the output terminal of the third field-effect transistor Q3, and the cathode is connected to the switch pin SW and the boost input terminal of the switching DC boost circuit.

[0037] Optionally, the power-on module 3 may also include a plurality of power-on resistors.

[0038] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0039] If the integrated units in the above embodiments are implemented as software functional units and sold or used as independent products, they can be stored in the aforementioned computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause one or more computer devices (which may be personal computers, servers, or network devices, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0040] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0041] In the several embodiments provided in this application, it should be understood that the disclosed client can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, indirect coupling or communication connection between units or modules, and may be electrical or other forms.

[0042] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the solution provided in this embodiment, depending on actual needs.

[0043] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0044] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A surge current suppression circuit, applied to a switching DC-DC boost circuit, the switching DC-DC boost circuit including a switching DC-DC boost chip, the switching DC-DC boost chip including a switching pin and a feedback pin, characterized in that, The surge current suppression circuit includes a feedback suppression module: The feedback suppression module includes a first voltage divider resistor and a current limiting resistor; The output terminal of the switching DC boost circuit is connected to the feedback pin through the first voltage divider resistor; The input terminal of the current-limiting resistor is directly connected to the boost input terminal of the switching DC-DC boost circuit, and the output terminal of the current-limiting resistor is connected to the feedback pin. At the moment of power-on, the boost input terminal of the switching DC-DC boost circuit is simultaneously powered on to establish a working voltage. The working voltage is directly applied to the feedback pin through the current-limiting resistor, instantly raising the potential of the feedback pin. After the switching DC-DC boost chip acquires the potential signal of the feedback pin in real time, because the potential of the feedback pin is higher than the internal reference voltage of the switching DC-DC boost chip, the switching DC-DC boost chip reduces the modulation frequency or duty cycle, slowing down the charging speed of the output terminal of the switching DC-DC boost circuit to the downstream end, thereby suppressing the surge current generated at the moment of power-on.

2. The surge current suppression circuit as described in claim 1, characterized in that, The feedback suppression module further includes a second voltage divider resistor, the input terminal of which is connected to the output terminal of the first voltage divider resistor, and the output terminal of the second voltage divider resistor is grounded.

3. The surge current suppression circuit as described in claim 1, characterized in that, It also includes a microcontroller and an auxiliary acquisition module. The enable terminal of the auxiliary acquisition module is connected to the first pin of the microcontroller, the input terminal of the auxiliary acquisition module is connected to the output terminal of the current-limiting resistor, and the output terminal of the auxiliary acquisition module is grounded. After the surge current disappears, the first pin of the microcontroller outputs a control signal to control the enable terminal of the auxiliary acquisition module to ground the output terminal of the current-limiting resistor, so that the feedback pin can acquire the output voltage of the switching DC boost circuit.

4. The surge current suppression circuit as described in claim 3, characterized in that, The auxiliary acquisition module includes an enable unit, a first auxiliary resistor, and a second auxiliary resistor; the input terminal of the enable unit is connected to the output terminal of the current limiting resistor, the output terminal of the enable unit is grounded, and the enable terminal of the enable unit is connected to the first pin of the microcontroller through the first auxiliary resistor; the input terminal of the second auxiliary resistor is connected to the output terminal of the first auxiliary resistor, and the output terminal of the second auxiliary resistor is grounded.

5. The surge current suppression circuit as described in claim 4, characterized in that, The enabling unit includes a first field-effect transistor.

6. A surge current suppression circuit as described in any one of claims 4-5, characterized in that, The auxiliary acquisition module also includes a first diode, the anode of which is connected to the output terminal of the current limiting resistor, and the cathode of which is connected to the output terminal of the first voltage dividing resistor.

7. The surge current suppression circuit as described in claim 3, characterized in that, The surge current suppression circuit also includes a power-on module. The enable terminal of the power-on module is connected to the second pin of the microcontroller. The input terminal of the power-on module is connected to the boost input terminal of the switching DC boost circuit. The output terminal of the power-on module is grounded.

8. The surge current suppression circuit as described in claim 7, characterized in that, The power-on module includes a second field-effect transistor (FET) and a third field-effect transistor (FET). The enable terminal of the second FET is connected to the second pin of the microcontroller, the output terminal of the second FET is grounded, and the input terminal of the second FET is connected to the input terminal of the third FET. The output terminal of the third FET is connected to the switch pin and the boost input terminal of the switch DC boost circuit, respectively, and the enable terminal of the third FET is connected to the input terminal of the second FET.

9. A surge current suppression circuit as described in claim 8, characterized in that, The switching DC-DC boost circuit includes a second diode, the anode of which is connected to the output terminal of the third field-effect transistor, and the cathode of which is connected to the switch pin and the boost input terminal of the switching DC-DC boost circuit.

10. A surge current suppression circuit as described in claim 8, characterized in that, The power-on module also includes multiple power-on resistors.

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