Three-wire common-mode inductor DC-DC vehicle-mounted step-down power supply

Abstract

The utility model relates to power supply technical field, concretely relates to a take three -wire common mode inductance DC -DC vehicle -mounted step -down power supply, including input interface, output interface, ground connection, three -wire common mode inductance, synchronous rectification module, BUCK control module and MUC control module, three -wire common mode inductance includes first winding, second winding and third winding, one end between first winding and second winding is equipped with capacitor C94, the other end between first winding and second winding is equipped with capacitor C51, one end between third winding and second winding is equipped with capacitor C91, the other end between third winding and second winding is equipped with capacitor C62, the utility model discloses the combination of setting three -wire common mode inductance and pi type filter assembly, effectively reduces common mode noise, helps equipment to satisfy electromagnetic interference standard, can effectively suppress high -frequency noise and low -frequency ripple simultaneously.

Description

Technical Field

[0001] This utility model relates to the field of power supply technology, specifically to a DC-DC vehicle step-down power supply with a three-wire common-mode inductor. Background Technology

[0002] In the field of DC-DC power supply technology, for DC-DC power supplies with a common ground output terminal for both input and output, the current common filtering design scheme is to add a common-mode inductor to the DC input positive terminal and ground, paired with a differential-mode inductor at the output, or vice versa. However, when this type of design undergoes electromagnetic compatibility (EMC) testing according to the GB / T18655 standard, whether using the conducted voltage method, current method, or radiated single-pole method, it exhibits severe exceedances in both high-frequency and low-frequency ranges. The reason for this is that because the power supply input and output share a single ground output terminal, it is impossible to implement a linear signal routing board as in the case of separate grounding for input and output. This limited routing method makes it difficult for filtering components to function effectively, failing to effectively filter out interference signals, ultimately resulting in EMC test results that do not meet the relevant standard requirements, severely restricting the application of this type of DC-DC power supply in scenarios with strict electromagnetic compatibility requirements. Utility Model Content

[0003] The purpose of this invention is to address the aforementioned shortcomings in the existing technology by providing a DC-DC vehicle step-down power supply with a three-wire common-mode inductor.

[0004] The objective of this utility model is achieved through the following technical solution: a DC-DC vehicle-mounted step-down power supply with a three-wire common-mode inductor, comprising an input interface, an output interface, a ground interface, a three-wire common-mode inductor, a synchronous rectification module, a BUCK control module, and a MUC control module; the three-wire common-mode inductor comprises a first winding, a second winding, and a third winding;

[0005] One end of the first winding is connected to the input interface; the other end of the first winding is connected to the input terminal of the synchronous rectification module; one end of the second winding is connected to the ground interface; the other end of the ground interface is connected to the internal ground of the power supply; one end of the third winding is connected to the output interface; the other end of the third winding is connected to the output terminal of the synchronous rectification module.

[0006] The control terminal of the synchronous rectification module is connected to the output terminal of the BUCK control module; the enable terminal of the BUCK control module is connected to the output terminal of the MUC control module.

[0007] A capacitor C94 is provided between one end of the first winding and one end of the second winding; a capacitor C51 is provided between the other end of the first winding and the other end of the second winding; a capacitor C91 is provided between one end of the third winding and one end of the second winding; and a capacitor C62 is provided between the other end of the third winding and the other end of the second winding.

[0008] The present invention is further configured such that a reverse connection protection module is provided between the other end of the first winding and the input end of the synchronous rectification module.

[0009] The present invention is further configured such that the reverse connection protection module includes a MOSFET Q8, a MOSFET Q1, a resistor R1, a capacitor C5, a resistor R2, and a Zener diode ZD1; the drain of the MOSFET Q8 is connected to the other end of the first winding; the source of the MOSFET Q8 is connected to the source of the MOSFET Q1; the drain of the MOSFET Q1 is connected to the other end of the first winding; one end of the resistor R1 is connected to the source of the MOSFET Q8; the other end of the resistor R1 is grounded through a resistor R2; the gates of the MOSFET Q8 and the MOSFET Q1 are respectively connected to the other end of the resistor R1; the positive terminal of the Zener diode ZD1 is connected to the input terminal of the synchronous rectification module; the Zener diode ZD1 is connected in parallel with both the resistor R1 and the capacitor C5.

[0010] The present invention is further configured such that the BUCK control module includes a BUCK control chip U2.

[0011] The present invention is further configured such that the synchronous rectification module includes MOSFET Q2 and MOSFET Q3; the drain of MOSFET Q2 is connected to the source of MOSFET Q1; the source of MOSFET Q2 is connected to the drain of MOSFET Q3; the source of MOSFET Q3 is grounded; the gates of MOSFET Q2 and MOSFET Q3 are respectively connected to the output terminal of BUCK control chip U2; and the source of MOSFET Q2 is connected to the other end of the third winding.

[0012] The present invention is further configured such that the MUC control module includes a MUC control chip U3 and a transistor Q4; the emitter of the transistor Q4 is grounded; the base of the transistor Q4 is connected to the output terminal of the MUC control chip U3; and the collector of the transistor Q4 is connected to the enable terminal of the BUCK control module.

[0013] The present invention is further configured such that the DC-DC vehicle step-down power supply with three-wire common-mode inductor also includes a current detection module; the input terminal of the current detection module is connected to the output terminal of the synchronous rectification module; and the output terminal of the current detection module is connected to the input terminal of the MUC control chip U3.

[0014] The present invention is further configured such that the DC-DC vehicle buck power supply with three-wire common-mode inductor also includes a linear voltage regulator module; the linear voltage regulator module includes a first buck chip U1 and a second buck chip U4; the input terminal of the first buck chip U1 is connected to the source of the MOSFET Q8; the output terminal of the first buck chip U1 is connected to the input terminal of the second buck chip U4; the output terminal of the first buck chip U1 is used to power the BUCK control module; the output terminal of the second buck chip U4 is used to power the MUC control module.

[0015] The beneficial effects of this utility model are as follows: By combining a three-wire common-mode inductor and a π-type filter component, this utility model effectively reduces common-mode noise, helps the equipment meet electromagnetic interference standards, and can effectively suppress high-frequency noise and low-frequency ripple. Attached Figure Description

[0016] Figure 1 This is a block diagram of the modules of this utility model;

[0017] Figure 2 This is a circuit diagram showing the input interface, output interface, grounding interface, and three-wire common-mode inductor of this utility model.

[0018] Figure 3 This is a circuit schematic diagram of the BUCK control module and synchronous rectification module of this utility model.

[0019] Figure 4 This is the circuit schematic diagram of the MUC control module of this utility model;

[0020] Figure 5 This is the circuit schematic diagram of the linear voltage regulator module of this utility model;

[0021] Wherein: 1. Input interface; 2. Output interface; 3. Grounding interface; 41. First winding; 42. Second winding; 43. Third winding. Detailed Implementation

[0022] The present invention will be further described in conjunction with the following embodiments.

[0023] Depend on Figures 1 to 5 As can be seen, the DC-DC vehicle step-down power supply with a three-wire common-mode inductor described in this embodiment includes an input interface 1, an output interface 2, a ground interface 3, a three-wire common-mode inductor, a synchronous rectification module, a BUCK control module, and a MUC control module; the three-wire common-mode inductor includes a first winding 41, a second winding 42, and a third winding 43;

[0024] One end of the first winding 41 is connected to the input interface 1; the other end of the first winding 41 is connected to the input terminal of the synchronous rectification module; one end of the second winding 42 is connected to the ground interface 3; the other end of the ground interface 3 is connected to the internal ground of the power supply; one end of the third winding 43 is connected to the output interface 2; the other end of the third winding 43 is connected to the output terminal of the synchronous rectification module.

[0025] The control terminal of the synchronous rectification module is connected to the output terminal of the BUCK control module; the enable terminal of the BUCK control module is connected to the output terminal of the MUC control module.

[0026] A capacitor C94 is provided between one end of the first winding 41 and one end of the second winding 42; a capacitor C51 is provided between the other end of the first winding 41 and the other end of the second winding 42; a capacitor C91 is provided between one end of the third winding 43 and one end of the second winding 42; and a capacitor C62 is provided between the other end of the third winding 43 and the other end of the second winding 42.

[0027] Specifically, the DC-DC vehicle step-down power supply with a three-wire common-mode inductor described in this embodiment uses a three-wire common-mode inductor, which is a passive electronic component used to suppress common-mode noise. By reducing common-mode noise, it helps the device meet electromagnetic interference standards. The three sets of coil windings of the three-wire common-mode inductor are wound on the same magnetic core. When a common-mode current flows through, the magnetic field is superimposed, and the three-wire common-mode inductor presents a high impedance, which hinders the passage of common-mode noise. For the normally operating differential-mode signal, the magnetic fields cancel each other out, and the inductor impedance is extremely low, hardly affecting the signal transmission. The three-wire common-mode inductor selectively suppresses common-mode noise through a magnetic coupling mechanism, while not affecting the normal differential-mode signal. Furthermore, this embodiment forms a π-type filter component between capacitor C94, the first winding 41, and capacitor C51, and another π-type filter component between capacitor C91, the third winding 43, and capacitor C62, thereby effectively suppressing high-frequency noise and low-frequency ripple simultaneously at both input interface 1 and output interface 2. This embodiment effectively reduces common-mode noise by combining a three-wire common-mode inductor and π-type filter components, helping the device meet electromagnetic interference standards, while also effectively suppressing high-frequency noise and low-frequency ripple.

[0028] This embodiment describes a DC-DC vehicle-mounted step-down power supply with a three-wire common-mode inductor. A reverse connection protection module is provided between the other end of the first winding 41 and the input terminal of the synchronous rectification module. The reverse connection protection module includes a MOSFET Q8, a MOSFET Q1, a resistor R1, a capacitor C5, a resistor R2, and a Zener diode ZD1. The drain of the MOSFET Q8 is connected to the other end of the first winding 41; the source of the MOSFET Q8 is connected to the source of the MOSFET Q1; the drain of the MOSFET Q1 is connected to the other end of the first winding 41; one end of the resistor R1 is connected to the source of the MOSFET Q8; the other end of the resistor R1 is grounded through a resistor R2; the gates of the MOSFET Q8 and the MOSFET Q1 are respectively connected to the other end of the resistor R1; the positive terminal of the Zener diode ZD1 is connected to the input terminal of the synchronous rectification module; and the Zener diode ZD1 is connected in parallel with both the resistor R1 and the capacitor C5.

[0029] Specifically, when the power supply is normally connected and input interface 1 is at a positive voltage, resistors R1 and R2 divide the voltage, providing appropriate gate voltages for MOSFETs Q8 and Q1, enabling them to conduct and allowing current to flow smoothly, thus supplying power to the subsequent stages. Figure 2 It outputs a 24V power supply.

[0030] If the power supply is reversed and input interface 1 is negative: at this time, the gate-source voltage of MOSFET Q8 and MOSFET Q1 cannot meet the conduction condition, MOSFET Q8 and MOSFET Q1 are cut off, thus breaking the circuit. Zener diode ZD1 cannot form a continuous high current circuit. The subsequent circuit is protected because there is no effective power supply path, avoiding damage to the devices due to reverse power supply.

[0031] The DC-DC vehicle step-down power supply with a three-wire common-mode inductor described in this embodiment includes a BUCK control module comprising a BUCK control chip U2.

[0032] This embodiment describes a DC-DC vehicle-mounted step-down power supply with a three-wire common-mode inductor. The synchronous rectification module includes MOSFETs Q2 and Q3. The drain of MOSFET Q2 is connected to the source of MOSFET Q1. The source of MOSFET Q2 is connected to the drain of MOSFET Q3. The source of MOSFET Q3 is grounded. The gates of MOSFET Q2 and Q3 are respectively connected to the output terminal of BUCK control chip U2. The source of MOSFET Q2 is connected to the other end of the third winding 43.

[0033] Specifically, in this embodiment, the DC-DC vehicle-mounted step-down power supply with a three-wire common-mode inductor has a synchronous rectification module whose input terminal is the 24V power output from the source of MOSFET Q1. The gates of MOSFET Q2 and Q3 are connected to the HO and LO ports of the BUCK control chip U2, respectively. The BUCK control chip U2 outputs PWM signals to the gates of MOSFET Q2 and Q3, respectively, thereby performing synchronous rectification of the 24V power supply. Figure 3 The output is a 12V power supply; this 12V power supply is finally output from the output interface 2 after passing through the π-type filter component formed between capacitor C91, the third winding 43 and capacitor C62.

[0034] This embodiment describes a DC-DC vehicle-mounted step-down power supply with a three-wire common-mode inductor. The MUC control module includes a MUC control chip U3 and a transistor Q4. The emitter of transistor Q4 is grounded; the base of transistor Q4 is connected to the output terminal of the MUC control chip U3; and the collector of transistor Q4 is connected to the enable terminal EN of the BUCK control module. Through these settings, the MUC control chip U3 can output a high or low level to control the on / off state of transistor Q4, thereby controlling the start and stop of the BUCK control module.

[0035] This embodiment describes a DC-DC automotive step-down power supply with a three-wire common-mode inductor. The power supply further includes a current detection module, which is a current detection chip U5. The input terminal of the current detection module is connected to the output terminal of the synchronous rectification module, and the output terminal IOUT of the current detection module is connected to the input terminal of the MUC control chip U3. This configuration facilitates the detection of the output current.

[0036] This embodiment describes a DC-DC automotive step-down power supply with a three-wire common-mode inductor. The power supply further includes a linear regulator module. The linear regulator module includes a first step-down chip U1 and a second step-down chip U4. The input terminal of the first step-down chip U1 is connected to the source of a MOSFET Q8. The output terminal of the first step-down chip U1 is connected to the input terminal of the second step-down chip U4. The output terminal of the first step-down chip U1 supplies power to the BUCK control module. The output terminal of the second step-down chip U4 supplies power to the MUC control module. The input terminal of the first step-down chip U1 is connected to a 24V power supply, which is stepped down to 12V to power the BUCK control chip U2. The 12V power supply is then stepped down to 5V by the second step-down chip U4 to power the MUC control chip U3.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the essence and scope of the technical solutions of this utility model.

Claims

1. A DC-DC vehicle on-board voltage reducing power supply with three-wire common mode inductance, characterized in that: It includes an input interface (1), an output interface (2), a ground interface (3), a three-wire common-mode inductor, a synchronous rectification module, a BUCK control module, and a MUC control module; the three-wire common-mode inductor includes a first winding (41), a second winding (42), and a third winding (43); One end of the first winding (41) is connected to the input interface (1); the other end of the first winding (41) is connected to the input terminal of the synchronous rectification module; one end of the second winding (42) is connected to the ground interface (3); the other end of the ground interface (3) is connected to the internal ground of the power supply; one end of the third winding (43) is connected to the output interface (2); the other end of the third winding (43) is connected to the output terminal of the synchronous rectification module; The control terminal of the synchronous rectification module is connected to the output terminal of the BUCK control module; the enable terminal of the BUCK control module is connected to the output terminal of the MUC control module. A capacitor C94 is provided between one end of the first winding (41) and one end of the second winding (42); a capacitor C51 is provided between the other end of the first winding (41) and the other end of the second winding (42); a capacitor C91 is provided between one end of the third winding (43) and one end of the second winding (42); and a capacitor C62 is provided between the other end of the third winding (43) and the other end of the second winding (42).

2. The DC-DC vehicle on-board voltage reducing power supply with three-wire common mode inductor according to claim 1, characterized in that: A reverse connection protection module is provided between the other end of the first winding (41) and the input end of the synchronous rectification module.

3. The DC-DC vehicle on-board voltage reducing power supply with three-wire common mode inductor according to claim 2, characterized in that: The reverse connection protection module includes MOSFET Q8, MOSFET Q1, resistor R1, capacitor C5, resistor R2, and Zener diode ZD1; the drain of MOSFET Q8 is connected to the other end of the first winding (41); the source of MOSFET Q8 is connected to the source of MOSFET Q1; the drain of MOSFET Q1 is connected to the other end of the first winding (41); one end of resistor R1 is connected to the source of MOSFET Q8; the other end of resistor R1 is grounded through resistor R2; the gates of MOSFET Q8 and MOSFET Q1 are respectively connected to the other end of resistor R1; the positive terminal of Zener diode ZD1 is connected to the input terminal of the synchronous rectification module; Zener diode ZD1 is connected in parallel with resistor R1 and capacitor C5.

4. The DC-DC vehicle on-board voltage reducing power supply with three-wire common mode inductor according to claim 3, characterized in that: The BUCK control module includes the BUCK control chip U2.

5. The DC-DC vehicle on-board voltage reducing power supply with three-wire common mode inductor according to claim 4, characterized in that: The synchronous rectification module includes MOSFET Q2 and MOSFET Q3; the drain of MOSFET Q2 is connected to the source of MOSFET Q1; the source of MOSFET Q2 is connected to the drain of MOSFET Q3; the source of MOSFET Q3 is grounded; the gates of MOSFET Q2 and MOSFET Q3 are respectively connected to the output terminal of BUCK control chip U2; the source of MOSFET Q2 is connected to the other end of the third winding (43).

6. The DC-DC vehicle on-board voltage reducing power supply with three-wire common mode inductor according to claim 1, characterized in that: The MUC control module includes a MUC control chip U3 and a transistor Q4; the emitter of the transistor Q4 is grounded; the base of the transistor Q4 is connected to the output terminal of the MUC control chip U3; and the collector of the transistor Q4 is connected to the enable terminal of the BUCK control module.

7. The DC-DC vehicle on-board voltage reducing power supply with three-wire common mode inductor according to claim 6, characterized in that: The DC-DC vehicle step-down power supply with a three-wire common-mode inductor also includes a current detection module; the input terminal of the current detection module is connected to the output terminal of the synchronous rectification module; the output terminal of the current detection module is connected to the input terminal of the MUC control chip U3.

8. The DC-DC vehicle on-board voltage reducing power supply with three-wire common mode inductor according to claim 3, characterized in that: The DC-DC vehicle buck power supply with a three-wire common-mode inductor also includes a linear regulator module; the linear regulator module includes a first buck chip U1 and a second buck chip U4; the input terminal of the first buck chip U1 is connected to the source of the MOSFET Q8; the output terminal of the first buck chip U1 is connected to the input terminal of the second buck chip U4; the output terminal of the first buck chip U1 is used to power the BUCK control module; the output terminal of the second buck chip U4 is used to power the MUC control module.

Images