An electric power supply circuit for an electric automatic vehicle instrument

Abstract

This utility model discloses a power supply circuit, belonging to the field of electric vehicle instrument technology, specifically relating to a power supply circuit for an electric vehicle instrument, including: a switching regulator U1, an input filter component, an output filter component, a voltage divider network component, and a Zener diode D1; this utility model adds a constant voltage circuit to the power supply circuit, which stably converts a wide input voltage range into DC output, while the input filter component filters out noise from the input power line and reduces the backflow of high-frequency current ripple generated during the operation of the switching regulator. The output filter component smooths the high-frequency pulsating current generated by the switching action into a relatively stable DC voltage and further filters out high-frequency noise. In addition, the voltage divider network component samples the voltage and feeds it back to the switching regulator U1 to adjust the output voltage to ensure that it is maintained at a set constant value, thereby achieving stable output voltage.

Description

Technical Field

[0001] This utility model discloses a power supply circuit, belonging to the field of electric vehicle instrument technology, specifically relating to a power supply circuit for an electric vehicle instrument. Background Technology

[0002] The main function of the instrument panel in an electric vehicle is to display key vehicle information, helping the driver to better control and understand the vehicle's status.

[0003] Electric vehicle dashboards typically include the following functions:

[0004] Speed ​​display: The most prominent area on the dashboard is used to display the speed of the electric vehicle, helping the driver to understand and control the vehicle speed in real time.

[0005] Mileage display: The dashboard usually displays the cumulative mileage, which records the total distance the vehicle travels from start to finish of a certain segment.

[0006] Battery level display: The battery status indicator shows the battery level and voltage status, helping the driver to judge the remaining battery level and charge it in time.

[0007] Headlight status indicator: Indicates whether the headlights are on, ensuring that the driver can see clearly ahead at night or in low light conditions.

[0008] Turn signal indicators: The arrows on both sides of the instrument panel represent left and right turn signals, enhancing driving safety.

[0009] However, the instrument panel of existing electric vehicles includes indications from multiple functional modules, and interference between these modules leads to unstable power output voltage. Utility Model Content

[0010] Purpose of this utility model: To provide a power supply circuit for an electric vehicle instrument panel, solving the problems mentioned above.

[0011] Technical solution: A power supply circuit for an electric automatic vehicle instrument panel, the power supply circuit comprising: a switching regulator U1, an input filter component, an output filter component, a voltage divider network component, and a Zener diode D1;

[0012] The input voltage of the input filter component is connected to the input terminal of the switching regulator U1, the Zener diode D1 and the input terminal of the output filter component are connected to the output terminal of the switching regulator U1, the input terminal of the voltage divider network component is connected to the feedback terminal of the switching regulator U1, and the output terminals of the output filter component and the voltage divider network component are connected to the output voltage.

[0013] The input filtering component includes: capacitor C1 and polarized capacitor C2.

[0014] The output filtering component includes: inductor L1, capacitor C3 and polarized capacitor C4;

[0015] The voltage divider network component includes resistors R1 and R2.

[0016] In a further embodiment, one end of capacitor C1 and one end of polarized capacitor C2 are connected to the input voltage VCC and to pin 1 of the switching regulator U1, and the other end of capacitor C1 and the other end of polarized capacitor C2 are grounded.

[0017] In a further embodiment, pin 2 of the switching regulator U1 is connected to the negative terminal of the Zener diode D1 and one end of the inductor L1. Pin 3 of the switching regulator U1 is connected to one end of the resistor R1, one end of the resistor R2, and one end of the capacitor C3. One end of the polarized capacitor C4 is connected to the other end of the inductor L1, the other end of the resistor R1, and the other end of the capacitor C3, and outputs a voltage VOUT. Pins 4 to 8 of the switching regulator U1 are grounded to the positive terminal of the Zener diode D1, the other end of the resistor R2, and the other end of the polarized capacitor C4.

[0018] Beneficial effects: This invention adds a constant voltage circuit to the power supply circuit, which stably converts a wider input voltage into DC output. At the same time, the input filter component filters out noise from the input power line and reduces the backflow of high-frequency current ripple generated by the switching regulator during operation. The output filter component smooths the high-frequency pulsating current generated by the switching action into a relatively stable DC voltage and further filters out high-frequency noise. In addition, the voltage divider network component samples the voltage and feeds it back to the switching regulator U1 to adjust the output voltage to ensure that it is kept at a set constant value. Thus, this invention can achieve stable output voltage. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the present invention.

[0020] Figure 2 This is the circuit diagram of this utility model. Detailed Implementation

[0021] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0024] An electric vehicle instrument power supply circuit, such as Figure 1 and Figure 2 As shown, it includes: a switching regulator U1, an input filter component, an output filter component, a voltage divider network component, and a Zener diode D1;

[0025] The input voltage of the input filter component is connected to the input terminal of the switching regulator U1, the Zener diode D1 and the input terminal of the output filter component are connected to the output terminal of the switching regulator U1, the input terminal of the voltage divider network component is connected to the feedback terminal of the switching regulator U1, and the output terminals of the output filter component and the voltage divider network component are connected to the output voltage.

[0026] The input filtering component includes: capacitor C1 and polarized capacitor C2.

[0027] The output filtering component includes: inductor L1, capacitor C3 and polarized capacitor C4;

[0028] The voltage divider network component includes resistors R1 and R2.

[0029] In one embodiment, such as Figure 2 As shown, one end of capacitor C1 and one end of polarized capacitor C2 are connected to the input voltage VCC and to pin 1 of the switching regulator U1, while the other ends of capacitor C1 and polarized capacitor C2 are grounded.

[0030] In one embodiment, such as Figure 2 As shown, pin 2 of the switching regulator U1 is connected to the negative terminal of the Zener diode D1 and one end of the inductor L1. Pin 3 of the switching regulator U1 is connected to one end of the resistor R1, one end of the resistor R2, and one end of the capacitor C3. One end of the polarized capacitor C4 is connected to the other end of the inductor L1, the other end of the resistor R1, and the other end of the capacitor C3, and outputs a voltage VOUT. Pins 4 to 8 of the switching regulator U1 are grounded to the positive terminal of the Zener diode D1, the other end of the resistor R2, and the other end of the polarized capacitor C4.

[0031] The switching regulator U1 internally contains an oscillator, a PWM / PFM controller, an error amplifier, a reference voltage source, a driver circuit, and an internal power switch (usually a MOSFET). It controls the on / off time and frequency of the switch based on a feedback signal to achieve voltage conversion and regulation.

[0032] In the switching regulator U1, pin 1 (VIN) is the input voltage pin, which is connected to the positive terminal of the input power supply; pin 2 (SW) is the switching node pin, which is connected to the output terminal of the internal switching transistor, the energy storage inductor L1, and the cathode of the Zener diode D1; pin 3 (FB) is the feedback pin, which receives the sampled voltage from the output voltage divider network and compares it with the internal reference to adjust the duty cycle.

[0033] In the output filter component, inductor L1 is an energy storage inductor, polarized capacitor C4 is an energy storage filter, and capacitor C3 is an output high-frequency filter capacitor, which filters out high-frequency noise. Energy is stored when the switch is on (current increases, magnetic energy increases), and energy is released when the switch is off (current decreases, magnetic energy is converted into electrical energy to supply the load). Together with the output polarized capacitor C4, it smooths the pulse current generated by the switch into DC.

[0034] During the period when the switching transistor is on and the inductor is storing energy, the polarized capacitor C4 provides part of the current to the load to maintain a stable output voltage; during the period when the switching transistor is off and the inductor is releasing energy, it absorbs and stores energy from the inductor. It filters out switching noise and high-frequency ripple, making the output voltage smoother and more stable.

[0035] During the off-state of the switching transistor, Zener diode D1 provides a low-loss path for the freewheeling current of inductor L1, maintaining the continuity of the load current. Schottky diodes (SS36 is a 3A / 60V Schottky diode) are well-suited for this application due to their low forward voltage drop and fast switching characteristics, significantly improving efficiency.

[0036] In the voltage divider network component, resistor R1 is the feedback resistor (upper resistor) and resistor R2 is the feedback resistor (lower resistor). Resistor R1 is responsible for proportionally attenuating the output voltage and sending it to the FB pin of the switching regulator U1. Resistor R2 divides the output voltage VOUT to obtain a sampling voltage. This sampling voltage should be compared with the reference voltage inside the switching regulator U1.

[0037] In the input filter component, capacitors C1 and C2 are input filter capacitors. They provide transient large current to the switching regulator U1, while filtering out noise from the input power line and reducing the high-frequency current ripple generated by the switching regulator U1 during operation that flows back to the input power supply.

[0038] Working principle: such as Figure 2 As shown, the switching regulator U1 is the core controller (containing the switching MOSFET). The power switching transistor inside the switching regulator U1 (connected between the VIN and SW pins) is constantly turned on (ON) and off (OFF) at high frequency.

[0039] Energy storage (conduction phase): When the switch is turned on: the current flows from the input VIN through the switch (SW), then through the inductor L1 to the output terminal (VOUT) to supply power to the load. When the current flows through the inductor L1, the inductor converts electrical energy into magnetic energy and stores it. At this time, the Zener diode D1 is turned off due to reverse bias, and the output polarity capacitor C4 is also charging.

[0040] Energy release (turn-off phase): When the switch is turned off: the current flowing through inductor L1 cannot change abruptly, and the inductor generates a reverse electromotive force (negative on the left and positive on the right). This reverse electromotive force causes Zener diode D1 to be forward biased and conduct. The magnetic energy stored in inductor L1 is converted into electrical energy, and the current continues to flow to the load and output polarity capacitor C4 through the loop formed by D1. At this time, the input power supply and the output terminal are disconnected.

[0041] In the input filter component, the energy storage inductor L1 and the output filter polarity capacitor C4 work together to smooth the high-frequency pulsating current generated by the switching action into a relatively stable DC voltage, while capacitor C3 further filters out high-frequency noise.

[0042] The voltage divider network component is used for feedback control: the output voltage VOUT is sampled through the resistor divider network (R1 and R2). The sampled voltage is fed back to the feedback pin (pin 3, FB) of the switching regulator U1. Simultaneously, the switching regulator U1 has an internal precision reference voltage, which is compared to the feedback sampled voltage.

[0043] When the sampled voltage is lower than the reference voltage, the switching regulator U1 will increase the on-time (duty cycle) of the switching transistor, allowing more energy to be transferred from the input to the output, thus increasing the output voltage.

[0044] When the sampled voltage is higher than the reference voltage, the switching regulator U1 will reduce the on-time (duty cycle) of the switching transistor, thereby reducing the energy transferred to the output and causing the output voltage to drop.

[0045] Through the closed-loop feedback control mechanism described above, the switching regulator U1 continuously and dynamically adjusts the duty cycle of the switching transistor, ensuring that the output voltage VOUT is accurately and stably output regardless of how the input voltage or load current changes within the specified range.

[0046] This circuit utilizes the U1 chip to control the high-speed switching of the internal power switching transistors, working in conjunction with the energy storage inductor L1 and freewheeling diode D1 to achieve efficient step-down conversion. Input capacitor C1 stabilizes the input voltage, while output capacitor C_OUT and ceramic capacitor L3 filter ripple to provide a stable 5V output. A voltage divider network formed by resistors R1 and R2 feeds the output voltage information back to the U1 chip. The chip continuously adjusts the on / off time (duty cycle) of the switching transistors, forming a precise closed-loop control system that ensures a stable output of 5V across a wide input voltage range (10V-60V). This is a highly efficient and widely applicable DC-DC voltage conversion solution.

[0047] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. An electric power supply circuit for an electric automatic vehicle instrument, characterized by comprising: The power supply circuit includes: a switching regulator U1, an input filter component, an output filter component, a voltage divider network component, and a Zener diode D1; The input voltage of the input filter component is connected to the input terminal of the switching regulator U1, the Zener diode D1 and the input terminal of the output filter component are connected to the output terminal of the switching regulator U1, the input terminal of the voltage divider network component is connected to the feedback terminal of the switching regulator U1, and the output terminals of the output filter component and the voltage divider network component are connected to the output voltage. The input filtering component includes: capacitor C1 and polarized capacitor C2. The output filtering component includes: inductor L1, capacitor C3 and polarized capacitor C4; The voltage divider network component includes resistors R1 and R2.

2. The electric power supply circuit for an electric automatic vehicle instrument according to claim 1, wherein One end of capacitor C1 and one end of polarized capacitor C2 are connected to the input voltage VCC and to pin 1 of the switching regulator U1. The other ends of capacitor C1 and the other ends of polarized capacitor C2 are grounded.

3. The electric power supply circuit for an electric automatic vehicle instrument according to claim 1, wherein Pin 2 of the switching regulator U1 is connected to the negative terminal of the Zener diode D1 and one end of the inductor L1. Pin 3 of the switching regulator U1 is connected to one end of the resistor R1, one end of the resistor R2, and one end of the capacitor C3. One end of the polarized capacitor C4 is connected to the other end of the inductor L1, the other end of the resistor R1, and the other end of the capacitor C3, and outputs a voltage VOUT. Pins 4 to 8 of the switching regulator U1 are grounded to the positive terminal of the Zener diode D1, the other end of the resistor R2, and the other end of the polarized capacitor C4.

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