A power-isolated button wake-up circuit

Abstract

The present invention relates to a power isolation key wake-up circuit, which utilizes the unidirectional conduction characteristics of diode D1 and diode D2. When the second system is not powered, pressing the key causes diode D2 to conduct, forming a loop in the first system, thereby detecting that the key is pressed and waking up the first system to power the second system. When the second system is normally powered, diode D1 can isolate the detection signal, and the detection signals in the two systems will not interfere with each other. Moreover, when the second system is normally powered, diode D2 is not conductive, and the current loop of the first system passes through the DC isolation power module and is connected to AGND after passing through BGND, and does not pass through diode D2, so the isolation of the two systems can still be achieved.

Description

Technical Field

[0001] The present invention relates to the field of power isolation circuits, and particularly to a key wake-up circuit for power isolation. Background Art

[0002] In industrial control equipment, sometimes power ground isolation between two systems is required. For example, in a power isolation system, there are a first system and a second system. The power supply of the second system is provided by the first system, and the ground of the first system is isolated from the ground of the second system.

[0003] When the first system does not supply power to the second system, generally, the first system needs to be woken up to supply power to the second system. Currently, the wake-up key is generally independently set in the first system to form a loop, and the wake-up key cannot be set in the second system.

[0004] Suppose the wake-up key is set in the second system. The first system should be able to detect whether the key in the second system is pressed. When the power isolation is not powered on, the impedance between the 0 potential of the first system (referred to as the ground of the first system, hereinafter replaced by AGND) and the 0 potential of the second system (referred to as the ground of the first system, hereinafter replaced by BGND) is very large, and the first system cannot detect whether the key is pressed or not. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a key wake-up circuit for power isolation, which can detect the key by the first system even when the second system is not powered, so as to achieve normal wake-up.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A key wake-up circuit for power isolation is applied to a power isolation system. The power isolation system includes a first system and a second system. The first system supplies power to the second system through a DC isolation power module. The key wake-up circuit includes a resistor R1, a resistor R2, a diode D1, a resistor R2 and a key. One end of the resistor R1 is connected to the power supply Va of the first system, and the other end is connected to the detection terminal KEY-IN-A of the first system and the key. One end of the resistor R2 is connected to the power supply Vb of the second system, and the other end is connected to the detection terminal KEY-IN-B of the second system on the one hand and the anode of the diode D1 on the other hand. The cathode of the diode D1 is connected to the key. The key is connected to the grounding terminal BGND of the second system on the one hand and is connected to the grounding terminal AGND of the first system through a diode D2 on the other hand. The anode of the diode D2 is connected to the key, and the cathode is connected to the grounding terminal AGND of the first system.

[0008] The model of the DC isolation power module is URB_YMD-15WR3.

[0009] After adopting the above solution, the present invention utilizes the one-way conduction characteristics of diode D1 and diode D2. When the second system is not powered, pressing the button causes diode D2 to conduct, forming a loop in the first system, thereby detecting that the button is pressed and waking up the first system to power the second system. When the second system is normally powered, diode D1 can isolate the detection signal, and the detection signals in the two systems will not interfere with each other. Moreover, when the second system is normally powered, diode D2 is not conducting, and the current loop of the first system passes through the DC isolation power module and connects to AGND via BGND, and does not pass through diode D2, so the isolation of the two systems can still be achieved. Brief Description of the Drawings

[0010] Figure 1 It is the circuit schematic diagram of the present invention.

[0011] Label Description:

[0012] The first system 10; the second system 20. Detailed Embodiment

[0013] The purpose of power isolation is to ensure that the devices of the two systems do not interfere with each other after they start working. As long as a certain connection is established between the first system 10 and the second system 20, but this connection does not affect the respective operations of the first system 10 and the second system 20, it is possible to achieve that the first system 10 can normally detect the button press even when the second system 20 is not powered. Based on this, as Figure 1 shown, the present invention discloses a button wake-up circuit for power isolation, which is applied to a power isolation system. The power isolation system includes a first system 10 and a second system 20, and the first system 10 supplies power to the second system 20 through a DC isolation power module DC1. In this embodiment, the model of the DC isolation power module DC1 is URB_YMD-15WR3, and the manufacturer is Guangzhou JSY.

[0014] Specifically, the button wake-up circuit includes a resistor R1, a resistor R2, a diode D1, a resistor R2, and a button SW1. One end of the resistor R1 is connected to the power supply Va of the first system 10, and the other end is connected to the detection terminal KEY-IN-A of the first system 10 and the button SW1; one end of the resistor R2 is connected to the power supply Vb of the second system 20, and the other end is connected to the detection terminal KEY-IN-B of the second system 20 on the one hand and the anode of the diode D1 on the other hand. The cathode of the diode D1 is connected to the button SW1. The button SW1 is connected to the ground terminal BGND of the second system 20 on the one hand and the ground terminal AGND of the first system 10 through a diode D2 on the other hand. The anode of the diode D2 is connected to the button SW1, and the cathode is connected to the ground terminal AGND of the first system 10.

[0015] The working principle of the present invention is as follows:

[0016] In the state where the first system 10 does not supply power to the second system 20, KEY-IN-A of the first system 10 detects a high level. When the button SW1 is pressed, the diode D2 conducts, and the button SW1 establishes a loop channel in the first system 10. Therefore, the detection terminal KEY-IN-A can detect a low-level signal, while the second system 20 is not affected because it is not powered. After the detection terminal KEY-IN-A of the first system 10 detects a low-level signal, the first system 10 supplies power to the second system 20 through the DC isolation power supply module DC1, and the second system 20 operates normally.

[0017] During the period when the second system 20 is being powered on, if the button is not pressed, the detection terminal KEY-IN-B of the second system 20 detects a high level. When the button SW1 is pressed, the power supply Vb supplies power normally, and the diode D1 conducts. The power supply Vb of the second system 20 forms a loop through the resistor R2, the diode D1, and SW1 to BGND, and the detection terminal KEY-IN-B detects a low level. Since the diode D1 can be used for signal isolation, the detection signals in the two systems do not interfere with each other. In the powered-on state of the second system 20, the impedance between AGND and BGND is very small. The diode D2 needs a conduction voltage drop of about 0.5V to conduct. Therefore, the circuit return path of the first system 10 does not pass through the diode D2, but flows to BGND and then flows to AGND through the DC isolation power supply module DC1, so the isolation effect can still be achieved.

[0018] The above is only an embodiment of the present invention, and does not impose any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A power isolation key wake-up circuit is applied to a power isolation system. The power isolation system includes a first system and a second system. The first system supplies power to the second system through a DC isolation power module. It is characterized in that: The key wake-up circuit includes a resistor R1, a resistor R2, a diode D1, a resistor R2, and a key. One end of the resistor R1 is connected to the power supply Va of the first system, and the other end of the resistor R1 is connected to the detection terminal KEY-IN-A of the first system and the first end of the key; one end of the resistor R2 is connected to the power supply Vb of the second system, and the other end of the resistor R2 is connected to the detection terminal KEY-IN-B of the second system on the one hand, and the anode of the diode D1 on the other hand. The cathode of the diode D1 is connected to the first end of the key. The second end of the key is connected to the ground terminal BGND of the second system. The second end of the key is connected to the ground terminal AGND of the first system through a diode D2. The anode of the diode D2 is connected to the second end of the key, and the cathode of the diode D2 is connected to the ground terminal AGND of the first system; In the state where the first system does not supply power to the second system, KEY-IN-A of the first system detects a high level; at this time, if the key is pressed, the power supply Va of the first system supplies power to the diode D2, making the diode D2 conduct, and then establishing a loop channel for the key in the first system, so that the detection terminal KEY-IN-A of the first system detects a low-level signal; after the detection terminal KEY-IN-A of the first system detects a low-level signal, the first system supplies power to the second system through the DC isolation power module, enabling the second system to work properly; During the normal power-on period of the second system, when the key is not pressed, the detection terminal KEY-IN-B of the second system detects a high level; when the key is pressed, the power supply Vb supplies power normally, making the diode D1 conduct. The power supply Vb of the second system forms a loop through the resistor R2, the diode D1, the key to the ground terminal BGND, and the detection terminal KEY-IN-B of the second system detects a low level.

2. A power isolation key wake-up circuit according to claim 1, It is characterized in that: The model of the DC isolation power module is URB_YMD-15WR3.

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