Power-down detection circuit and circuit board

Abstract

The utility model relates to electronic circuit technical field, concretely relates to a power -down detection circuit and circuit board, including main power supply, spare power supply and power -down detection circuit, the main power supply produces after -stage output through DCDC converter, spare power supply is connected with DCDC converter, power -down detection circuit is connected with main power supply, spare power supply and after -stage output respectively, is used for detecting whether main power supply is power -down, and when main power supply power -down, switches into spare power supply and supplies power, the utility model discloses through pure hardware logic realizes main power supply power -down detection and spare power supply switching, and circuit structure is simple and low in cost.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, specifically to a power failure detection circuit and circuit board. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the demand for charging piles is also increasing daily. To ensure that the charging pile system can maintain basic safety functions, guarantee transaction and data integrity, and maintain necessary communication and status display when the main power supply fails, a backup power supply must be configured, and seamless switching between the main and backup power supplies must be achieved.

[0003] For example, Chinese utility model patent with publication number CN207782478U discloses a power supply for a charging pile control system. By setting an energy storage capacitor and integrating a power failure detection circuit and a power switching circuit, when the power supply to the charging pile control system is interrupted, the power failure detection circuit detects the power failure signal and sends it to the charging pile control system. The charging pile control system then controls the power switching circuit to switch the power supply to the charging pile control system through the energy storage capacitor.

[0004] However, in the aforementioned patent content, the switching of backup power relies on the software control of the control system. If the software malfunctions or the response is delayed, it may lead to switching failure, posing a safety risk. Secondly, the circuit structure of this solution is relatively complex, which increases the system cost and the difficulty of implementation. Utility Model Content

[0005] The purpose of this utility model is to provide a power failure detection circuit and circuit board that realizes main power failure detection and backup power switching through pure hardware logic, and the circuit structure is simple and low cost.

[0006] To achieve the above objectives, this utility model provides the following technical solution: In a first aspect, this utility model provides a power failure detection circuit, including a main power supply, a backup power supply, and a power failure detection circuit. The main power supply generates a downstream output through a DC-DC converter. The backup power supply is connected to the DC-DC converter. The power failure detection circuit is connected to the main power supply, the backup power supply, and the downstream output, respectively, for detecting whether the main power supply has lost power, and switching to the backup power supply when the main power supply loses power.

[0007] In conjunction with the first aspect, optionally, the power failure detection circuit includes an optocoupler U1 and a voltage detector U2. The first pin of the optocoupler U1 is connected to the positive terminal of the main power supply through a resistor R1, the second pin of the optocoupler U1 is connected to the negative terminal of the main power supply, the fourth pin of the optocoupler U1 is connected to the output of the subsequent stage, and the third pin of the optocoupler U1 is grounded after passing through resistors R2 and R3 in sequence. The end of resistor R2 closest to resistor R3 is connected to the main control unit. The fourth pin of the optocoupler U1 is also connected to the VCC pin of the voltage detector U2. The RESET pin of the voltage detector U2 is connected to the backup power supply, and the GND pin of the voltage detector U2 is grounded.

[0008] In conjunction with the first aspect, optionally, the optocoupler U1 is model EL3H7(B)(TA)-G.

[0009] In conjunction with the first aspect, optionally, the voltage detector U2 is of the MAX810 series or the MAX809 series.

[0010] In a second aspect, the present invention provides a circuit board, including a substrate and a power-down detection circuit; wherein the substrate is used to support the power-down detection circuit, and the power-down detection circuit is the power-down detection circuit described in any one of the first aspects.

[0011] The beneficial effects of this utility model are: 1) The power failure detection circuit is connected to the main power supply and the backup power supply respectively. It can be used to detect whether the main power supply has failed. When the main power supply fails, it directly switches to the backup power supply. The switching of the backup power supply is realized through pure hardware logic, which reduces the safety risks caused by relying on software. The hardware logic of this utility model is simple and the cost is low.

[0012] 2) The first and second pins of optocoupler U1 are connected to the positive and negative terminals of the main power supply. When the main power supply is powered, optocoupler U1 is turned on, and the connection point between resistors R2 and R3 and the main control unit rises to a high level. Conversely, when the main power supply is de-energized, this point is at a low level. At the same time, when the main power supply is powered, optocoupler U1 is turned on, and the voltage at the VCC pin of voltage detector U2 is greater than the preset voltage. Therefore, the RESET pin of voltage detector U2 outputs a low level. Conversely, when the main power supply is de-energized, the voltage at the VCC pin of voltage detector U2 is less than the preset voltage, and the RESET pin of voltage detector U2 is consistent with the voltage at the VCC pin, which is a high level. The RESET pin of voltage detector U2 is connected to the backup power supply. Therefore, when the main power supply is de-energized, the RESET pin of voltage detector U2 sends a high level, turning on the backup power supply. This utility model realizes the switching of the backup power supply through pure hardware logic, which is simple and low in cost. Attached Figure Description

[0013] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a module diagram of this utility model; Figure 2 This is the power-off detection circuit diagram of this utility model. Detailed Implementation

[0014] The technical solution of this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of this application, rather than limitations thereof.

[0015] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0016] Example 1:

[0017] like Figure 1 As shown, this utility model provides a power failure detection circuit, including a main power supply, a backup power supply, and a power failure detection circuit. The main power supply generates a downstream output through a DC-DC converter. The backup power supply is connected to the DC-DC converter. The power failure detection circuit is connected to the main power supply, the backup power supply, and the downstream output, respectively, and is used to detect whether the main power supply has lost power, and to switch to the backup power supply when the main power supply loses power.

[0018] like Figure 2 As shown, the power failure detection circuit includes an optocoupler U1 and a voltage detector U2. The first pin of the optocoupler U1 is connected to the positive terminal of the main power supply through a resistor R1, the second pin of the optocoupler U1 is connected to the negative terminal of the main power supply, the fourth pin of the optocoupler U1 is connected to the output of the subsequent stage, and the third pin of the optocoupler U1 is grounded after passing through resistors R2 and R3 in sequence. The end of resistor R2 closest to resistor R3 is connected to the main control unit. The fourth pin of the optocoupler U1 is also connected to the VCC pin of the voltage detector U2. The RESET pin of the voltage detector U2 is connected to the backup power supply, and the GND pin of the voltage detector U2 is grounded.

[0019] The first and second pins of optocoupler U1 are connected to the positive and negative terminals of the main power supply. When the main power supply is powered, optocoupler U1 is turned on, and the connection point between resistors R2 and R3 and the main control unit rises to a high level. Conversely, when the main power supply is de-energized, this point is at a low level. At the same time, when the main power supply is powered, optocoupler U1 is turned on, and the voltage at the VCC pin of voltage detector U2 is greater than the preset voltage. Therefore, the RESET pin of voltage detector U2 outputs a low level. Conversely, when the main power supply is de-energized, the voltage at the VCC pin of voltage detector U2 is less than the preset voltage, and the RESET pin of voltage detector U2 is consistent with the voltage at the VCC pin, which is a high level. The RESET pin of voltage detector U2 is connected to the backup power supply. Therefore, when the main power supply is de-energized, the RESET pin of voltage detector U2 sends a high level, turning on the backup power supply.

[0020] In some illustrative embodiments, the optocoupler U1 is model EL3H7(B)(TA)-G; in some embodiments, the optocoupler U1 can be a general optocoupler, a high-speed optocoupler, or a solid-state relay, which can be selected according to the specific application scenario.

[0021] In some illustrative embodiments, the voltage detector U2 is of the MAX810 series or MAX809 series.

[0022] Example 2:

[0023] This utility model provides a circuit board, including a substrate and a power failure detection circuit; wherein, the substrate is used to support the power failure detection circuit, and the power failure detection circuit is the power failure detection circuit described in any one of Embodiment 1.

[0024] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A power-down detection circuit, characterized in that, It includes a main power supply, a backup power supply, and a power failure detection circuit. The main power supply generates the output stage through a DC-DC converter. The backup power supply is connected to the DC-DC converter. The power failure detection circuit is connected to the main power supply, the backup power supply, and the output stage, respectively, and is used to detect whether the main power supply has lost power, and to switch to the backup power supply when the main power supply loses power.

2. The power failure detection circuit according to claim 1, characterized in that, The power failure detection circuit includes an optocoupler U1 and a voltage detector U2. The first pin of the optocoupler U1 is connected to the positive terminal of the main power supply through a resistor R1. The second pin of the optocoupler U1 is connected to the negative terminal of the main power supply. The fourth pin of the optocoupler U1 is connected to the output of the subsequent stage. The third pin of the optocoupler U1 is grounded after passing through resistors R2 and R3 in sequence. The end of resistor R2 closest to resistor R3 is connected to the main control unit. The fourth pin of the optocoupler U1 is also connected to the VCC pin of the voltage detector U2. The RESET pin of the voltage detector U2 is connected to the backup power supply. The GND pin of the voltage detector U2 is grounded.

3. The power-down detection circuit according to claim 2, characterized in that, The optocoupler U1 is model number EL3H7(B)(TA)-G.

4. The power failure detection circuit according to claim 2, characterized in that, The voltage detector U2 is of the MAX810 series or MAX809 series.

5. A circuit board, characterized in that, It includes a substrate and a power-down detection circuit; wherein the substrate is used to carry the power-down detection circuit, and the power-down detection circuit is the power-down detection circuit according to any one of claims 1-4.

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