Circuit for inputting alternating current and direct current and outputting direct current

Abstract

The utility model provides a circuit for inputting alternating current and direct current and outputting direct current, which comprises an input interface CN1, an output interface CN2, an alternating current and direct current switching circuit consisting of an alternating current relay U1, an alternating current to direct current power supply circuit consisting of an alternating current to direct current power supply module U2, and an output control circuit consisting of a control interface CN3, a diode D2 and a relay K1, and the output holding circuit is composed of a relay K2. According to the utility model, accessed alternating current and direct current are controlled by the alternating current relay to enter a circuit through different channels, alternating current harmful to a direct current electric circuit is isolated from a rear-end direct current circuit through the cooperation of the direct current relay, and the device has the characteristics of simple structure, low direct current voltage and high reliability. By adding the indicating circuit, wiring personnel can be prompted of fault reasons on the premise that a rear-end direct-current electricity utilization circuit is not damaged. Meanwhile, powerful guarantee is provided for teaching, training and training of wiring of the electric equipment and development of an assessment device.

Description

Technical Field

[0001] The utility model relates to a circuit, in particular to a circuit that inputs alternating current and direct current and outputs direct current. Background Art

[0002] When some electronic products are working, they need an external DC power supply input. The appearance and markings of some devices are very similar, and it is impossible to distinguish whether the required input power is DC or AC through the markings on the wiring terminals. If AC power is wrongly connected to the device, it will cause damage to the device and even damage to the debugging computer. Since the maximum value of the AC voltage is about 311V, which is more than 10 times that of the common 5V, 12V, and 24V DC power. At present, DC-powered devices mainly use a rectifier bridge to adjust the current direction and then connect the DC power to the circuit. However, after AC power is connected, due to the too high peak voltage, the common circuits that require DC power supply will generate a large current due to the high voltage, causing damage to voltage regulators, filter capacitors, power supply chips, control chips, etc. Although adding diodes can block the wrongly directed DC power from being introduced into the circuit, it cannot block the introduction of AC power, and thus will also cause damage to the device. Content of the Utility Model

[0003] To solve the above problems, the purpose of the utility model is to provide a circuit that inputs alternating current and direct current and outputs direct current. Through this circuit, the connected AC and DC can enter the circuit through different channels, and the AC that is harmful to the DC power consumption circuit can be isolated from the backend DC circuit.

[0004] The purpose of the utility model is achieved through the following technical solutions:

[0005] A circuit for inputting AC and DC and outputting DC, comprising an input interface CN1, an output interface CN2, an AC relay U1, an AC-DC power supply module U2, a control interface CN3, a diode D2, a relay K1 and a relay K2; the output end of the input interface CN1 has a contact VIN_P for connecting to the live wire or the positive power supply, a contact VIN_N for connecting to the neutral wire or the negative power supply, and a ground wire contact PE; the input end of the output interface CN2 has a positive contact DCOUT+, a negative contact DCOUT-, and a ground wire contact PE; the AC relay U1 has an AC relay U1 coil U1.7 and two normally closed contacts and two normally open contacts. The two ends of the AC relay U1 coil U1.7 are respectively connected one-to-one to the contact VIN_P and the contact VIN_N of the input interface CN1; one end of the normally closed contact U1.1 of the AC relay U1 is connected to the contact VIN_P of the input interface CN1, and the other end of the normally closed contact U1.1 of the AC relay U1 is connected to one end of the normally open contact U1.5 of the AC relay U1 to form a first common contact; one end of the normally closed contact U1.2 of the AC relay U1 is connected to the contact VIN_N of the input interface CN1, and the other end of the normally closed contact U1.2 of the AC relay U1 is connected to one end of the normally open contact U1.4 of the AC relay U1 to form a second common contact; the input end of the AC-DC power supply module U2 is connected to the output end of the input interface CN1, the positive contact of the output end of the AC-DC power supply module U2 is connected to the other end of the normally open contact U1.5 of the AC relay U1, and the negative contact of the output end of the AC-DC power supply module U2 is connected to the other end of the normally open contact U1.4 of the AC relay U1; the input end of the control interface CN3 is externally connected with a push-button switch. The first connection point of the output end of the control interface CN3 is connected to the first common contact, and the second connection point of the output end of the control interface CN3 is respectively connected to the positive pole of the diode D2 and the positive contact DCOUT+ of the output interface CN2; one end of the relay K1 coil K1.3 is connected to the negative pole of the diode D2, and the other end is connected to the second common contact; one end of the normally open contact K1.2 of the relay K1 is connected to the second common contact, and the other end is connected to the negative contact DCOUT- of the output interface CN2; one end of the relay K2 coil K2.3 is connected to the negative pole of the diode D2, and the other end is connected to the second common contact; one end of the normally open contact K2.2 of the relay K2 is connected to the first connection point of the control interface CN3, and the other end is connected to the second connection point of the control interface CN3.

[0006] Further, the circuit for inputting AC and DC and outputting DC is characterized in that: it further comprises a filtering circuit, and the filtering circuit is composed of an energy storage filtering capacitor C1. One end of the energy storage filtering capacitor C1 is connected to the second connection point of the control interface CN3, and the other end is connected to the negative pole of the output interface CN2.

[0007] Further, the AC relay U1 constitutes an AC-DC switching circuit for performing AC-DC switching; the AC-DC power supply module U2 constitutes an AC-DC power supply circuit for converting AC into DC; the control interface CN3, diode D2, and relay K1 constitute an output control circuit; the relay K2 constitutes an output holding circuit.

[0008] Further, the circuit for inputting AC / DC and outputting DC further includes an input AC indication circuit and a DC output indication circuit; the input AC indication circuit is composed of a resistor R3 and a light-emitting diode LED3; one end of the resistor R3 is connected to the negative contact of the output terminal of the AC-DC power supply module U2, the other end of the resistor R3 is connected to the negative electrode of the light-emitting diode LED3, and the positive electrode of the light-emitting diode LED3 is connected to the positive contact of the output terminal of the AC-DC power supply module U2; the DC output indication circuit is composed of a resistor R2 and a light-emitting diode LED2; one end of the resistor R2 is connected to the second connection point of the control interface CN3, the other end of the resistor R2 is connected to the positive electrode of the light-emitting diode LED2, and the negative electrode of the light-emitting diode LED2 is connected to the negative pole of the output interface CN2.

[0009] Further, the output control circuit further includes a diode D4 for freewheeling, the negative electrode of the diode D4 is connected to the negative electrode of the diode D2, and the positive electrode of the diode D4 is connected to the second common terminal.

[0010] Further, the power supply input through the input interface CN1 is DC or AC; the power supply output through the output interface CN2 is DC.

[0011] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0012] The present utility model controls the access of AC and DC to enter the circuit through different channels through an AC relay. Through the cooperation of a DC relay, the AC harmful to the DC power consumption circuit is isolated from the backend DC circuit, and it has the characteristics of simple structure, low DC voltage drop, and high reliability. By adding an indication circuit, it can prompt the wiring personnel of the fault cause without damaging the backend DC power consumption circuit. At the same time, it also provides a strong guarantee for the development of teaching, training, training, and assessment devices for the wiring of electrical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The following further describes the present utility model in detail with reference to the drawings.

[0014] Figure 1 is the control logic diagram of the circuit described in the present utility model.

[0015] Figure 2 is the circuit schematic diagram of the circuit described in the present utility model when no power supply is connected.

[0016] Figure 3 This is the circuit schematic diagram of the circuit described in the present utility model when it is connected to an AC power supply.

[0017] Figure 4 This is the circuit schematic diagram of the circuit described in the present utility model when it is connected to a DC power supply.

[0018] Figure 5 This is the physical connection diagram of the circuit described in the present utility model.

[0019] As shown in the figure:

[0020] C1 Energy storage and filtering capacitor;

[0021] CN1 Input interface;

[0022] CN2 Output interface;

[0023] CN3 Control interface;

[0024] D2 Diode;

[0025] K1, K2 Relays;

[0026] K1.2 Normally open contact of relay K1;

[0027] K1.3 Coil of relay K1;

[0028] K2.2 Normally open contact of relay K2;

[0029] K2.3 Coil of relay K2;

[0030] LED1, LED2 Light-emitting diodes;

[0031] R2, R3 Resistors;

[0032] U1 AC relay;

[0033] U1.1, U1.2 Normally closed contacts of AC relay U1;

[0034] U1.4, U1.5 Normally open contacts of AC relay U1;

[0035] U1.7 Coil of AC relay U1;

[0036] U2 AC to DC power supply module. Specific embodiments

[0037] The following specific embodiments illustrate the implementation manners of the present utility model. Those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. The described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0038] In the description of the present utility model, it should be noted that, unless otherwise clearly defined and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0039] In the present utility model, each electrical component, such as the energy storage filter capacitor C1, the input interface CN1, the output interface CN2, the control interface CN3, the diode D4, the relays K1 and K2, the light-emitting diodes LED1 and LED2, the resistors R2 and R3, the AC relay U1, and the AC-DC power supply module U2, are all existing components; the relays K1 and K2 are DC relays, and both DC relays and AC relays have normally closed contacts, normally open contacts, and coils; the light-emitting diodes and diodes have positive and negative poles; the AC-DC power supply module is used to convert alternating current into direct current. Embodiment 1

[0040] As Figure 1 shown in Figure 2 this embodiment provides a circuit for inputting AC and DC and outputting DC, which includes an input interface CN1 for inputting power, an output interface CN2 for outputting power, an AC-DC switching circuit composed of an AC relay U1, an AC-DC power supply circuit composed of an AC-DC power supply module U2, an output control circuit composed of a control interface CN3, a diode D2, and a relay K1, and an output holding circuit composed of a relay K2.

[0041] The input end of the input interface CN1 is connected to the power supply, and the output end of the input interface CN1 has three contacts, namely the contact VIN_P (for connecting to the live wire or the positive pole of the power supply), the contact VIN_N (for connecting to the neutral wire or the negative pole of the power supply), and the ground wire contact PE.

[0042] The output end of the output interface CN2 is connected to the load, and the input end of the output interface CN2 has three contacts, namely the positive pole contact DCOUT+, the negative pole contact DCOUT-, and the ground wire contact PE.

[0043] In the AC / DC switching circuit, the AC relay U1 has an AC relay U1 coil U1.7, as well as two normally closed contacts and two normally open contacts. The two normally closed contacts are respectively the normally closed contact U1.1 of the AC relay U1 and the normally closed contact U1.2 of the AC relay U1. The two normally open contacts are respectively the normally open contact U1.4 of the AC relay U1 and the normally open contact U1.5 of the AC relay U1. The two ends of the AC relay U1 coil U1.7 are respectively connected one-to-one to the contacts VIN_P and VIN_N of the input interface CN1. The AC relay U1 coil U1.7 is a 110V coil or a 220V coil or a coil above 220V (the coil voltage of the AC relay U1 coil U1.7 is the same as the input AC voltage. Usually, the AC voltage is 220V, and the AC relay U1 coil is a 220V coil. When inputting DC power, the DC voltage is less than 36V, usually 24V). One end of the normally closed contact U1.1 of the AC relay U1 is connected to the contact VIN_P of the input interface CN1. The other end of the normally closed contact U1.1 of the AC relay U1 and one end of the normally open contact U1.5 of the AC relay U1 are connected together (through a wire) to form a first common contact. One end of the normally closed contact U1.2 of the AC relay U1 is connected to the contact VIN_N of the input interface CN1. The other end of the normally closed contact U1.2 of the AC relay U1 and one end of the normally open contact U1.4 of the AC relay U1 are connected together (through a wire) to form a second common contact.

[0044] In the AC-to-DC power supply circuit, the AC-to-DC power supply module U2 has a live wire interface L, a neutral wire interface N, and a ground wire interface FG at its input end, and a positive contact and a negative contact at its output end. The input end of the AC-to-DC power supply module U2 is connected to the output end of the input interface CN1. Specifically, the live wire interface L at the input end of the AC-to-DC power supply module U2 is connected to the contact VIN_P of the input interface CN1. The neutral wire interface N at the input end of the AC-to-DC power supply module U2 is connected to the contact VIN_N of the input interface CN1. The ground wire interface FG at the input end of the AC-to-DC power supply module U2 is connected to the ground contact PE of the input interface CN1. The positive contact (+24V) at the output end of the AC-to-DC power supply module U2 is connected to the other end of the normally open contact U1.5 of the AC relay U1. The negative contact (0V) at the output end of the AC-to-DC power supply module U2 is connected to the other end of the normally open contact U1.4 of the AC relay U1.

[0045] In the output control circuit, a push-button switch (momentary push button) is externally connected to the input end of the control interface CN3. The input end of the control interface CN3 has two connection points (the first connection point and the second connection point, and the two connection points are normally open contacts. Only when the push-button switch is pressed, the two normally open contacts will be closed). The first connection point of the control interface CN3 is connected to the first common contact, and the second connection point of the control interface CN3 is respectively connected to the positive pole of the diode D2 and the positive contact DCOUT+ of the output interface CN2. The relay K1 includes a relay K1 coil K1.3 and a relay K1 normally open contact K1.2. One end of the relay K1 coil K1.3 is connected to the negative pole of the diode D2, and the other end of the relay K1 coil K1.3 is connected to the second common contact. One end (common end) of the relay K1 normally open contact K1.2 is connected to the second common contact, and the other end (normally open end) of the relay K1 normally open contact K1.2 is connected to the negative contact DCOUT- of the output interface CN2.

[0046] In the output holding circuit, the relay K2 includes a relay K2 normally open contact K2.2 and a relay K2 coil K2.3. One end of the relay K2 coil K2.3 is connected to the negative pole of the diode D2, and the other end of the relay K2 coil K2.3 is connected to the second common contact. One end of the relay K2 normally open contact K2.2 is connected to the first connection point of the control interface CN3, and the other end of the relay K2 normally open contact K2.2 is connected to the second connection point of the control interface CN3.

[0047] Working principle:

[0048] (1) The input power supply is alternating current

[0049] As Figure 3 shown, when 220V alternating current is connected to the input interface CN1, the coil U1.7 of the AC relay U1 is energized, the normally closed contacts U1.1 of the AC relay U1 and the normally closed contacts U1.1 of the AC relay U1 are disconnected, and the normally open contacts U1.4 of the AC relay U1 and the normally open contacts U1.4 of the AC relay U1 are conducting. The 220V alternating current enters from the input end of the AC-to-DC power supply module U2 and is converted into 24V direct current by the AC-to-DC power supply module U2, and then the direct current is output from the output end of the AC-to-DC power supply module U2 and introduced into the output control circuit. Press the push-button switch connected to the control interface CN3 to connect the wire between the first common end point and the positive pole of the diode D2. The diode D2 is energized and conducts (its wiring direction is the same as the direction of the direct current output by the AC-to-DC power supply module U2). The relay K1 coil K1.3 is energized, the relay K1 normally open contact K1.2 is closed, and the DC power supply is output via the output interface CN2. At the same time, the relay K2 coil K2.3 is energized, and the relay K2 normally open contact K2.2 is closed to keep the circuit output.

[0050] (2) The input power supply is direct current

[0051] As Figure 4 shown, when the input interface CN1 is connected to a direct current of 24V (usually 24V), the AC relay U1 does not operate. The normally closed contacts U1.1 of the AC relay U1 and the normally closed contacts U1.1 of the AC relay U1 remain closed, and the normally open contacts U1.4 of the AC relay U1 and the normally open contacts U1.4 of the AC relay U1 remain open. At this time, press the push-button switch connected to the control interface CN3 to connect the wire between the first common end point and the positive pole of the diode D2. The diode D2 is energized and conducts (its wiring direction is consistent with the direction of the direct current). The coil K1.3 of the relay K1 is energized, and the normally open contact K1.2 of the relay K1 closes. The DC power supply is output via the output interface CN2. At the same time, the coil K2.3 of the relay K2 is energized, and the normally open contact K2.2 of the relay K2 closes to maintain the circuit output.

[0052] Due to the characteristics of the AC relay, for each set of normally open and normally closed contacts, because of the mechanical structure characteristics, the normally open contacts will not close before the normally closed contacts open, avoiding the direct short circuit of the AC input to the circuit and the DC power output by the AC-DC power module U2, which may damage the AC-DC power module U2.

[0053] The coil of the AC relay U1 is directly connected to the input channel of the circuit. As soon as the alternating current is input, the contacts of the AC relay will operate. The normally open contacts of the momentary push-button externally connected through the control interface CN3 and the normally open contact K1.2 of the relay K1 prevent the output of the alternating current before the AC relay U1 operates. Embodiment 2

[0054] In order to clearly indicate whether the input power supply is alternating current and whether the output power supply is direct current output, the following settings are added to this embodiment on the basis of Embodiment 1:

[0055] As Figure 2 shown, the circuit for inputting alternating current and outputting direct current further includes an input AC indication circuit and a DC output indication circuit.

[0056] The input AC indication circuit consists of a resistor R3 and a light-emitting diode LED3; one end of the resistor R3 is connected to the negative contact point (0V) of the output terminal of the AC-DC power supply module U2, the other end of the resistor R1 is connected to the negative electrode of the light-emitting diode LED3, and the positive electrode of the light-emitting diode LED3 is connected to the positive contact point (+24V) of the output terminal of the AC-DC power supply module U2. When the input interface CN1 is connected to an AC power supply, the power direction output by the AC-DC power supply module U2 is consistent with the wiring direction of the light-emitting diode LED3, and the light-emitting diode LED3 is in the conducting state, and the light-emitting diode LED3 emits light, indicating that the input power supply is an alternating current; if the input interface CN1 is connected to a DC power supply, the AC-DC power supply module U2 does not work, and the light-emitting diode LED3 will not conduct or emit light.

[0057] The DC output indication circuit consists of a resistor R2 and a light-emitting diode LED2; one end of the resistor R2 is connected to the second connection point of the control interface CN3, the other end of the resistor R2 is connected to the positive electrode of the light-emitting diode LED2, and the negative electrode of the light-emitting diode LED2 is connected to the negative electrode of the output interface CN2; when the output power supply is DC, the power direction is consistent with the wiring direction of the light-emitting diode LED2, and the DC output indication circuit is energized and conducts, and the light-emitting diode LED1 conducts and emits light, indicating that the output power supply is a DC power supply. Embodiment 3

[0058] In order to store energy and filter the input power supply and improve the quality of the DC power supply, the following settings are added in this embodiment on the basis of Embodiment 1 or Embodiment 2:

[0059] The circuit for the input positive and reverse direct current to output positive direct current further includes a filter circuit, and the filter circuit consists of an energy storage filter capacitor C1. One end of the energy storage filter capacitor C1 is connected to the second connection point of the control interface CN3, and the other end is connected to the negative electrode of the output interface CN2. Embodiment 4

[0060] Since the relay coil will store energy and there is a reverse voltage when it is disconnected, it needs to be discharged to avoid damaging other components. Therefore, freewheeling is required to avoid sudden changes in the load current and play a role in smoothing the current. The following settings are added in this embodiment on the basis of any one of Embodiments 1-3:

[0061] The output control circuit further includes a diode D4 for freewheeling. The negative electrode of the diode D4 is connected to the negative electrode of the diode D2, and the positive electrode of the diode D4 is connected to the second common end point.

[0062] Other details not elaborated in this utility model are all well-known conventional techniques in the art.

[0063] It should be noted that the term "including", "comprising" or any other variant is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0064] The protection scope of the present utility model is not limited to the technical solutions disclosed in the specific embodiments. Any modification, equivalent replacement, improvement, etc. made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A circuit for inputting AC and DC and outputting DC, comprising an input interface CN1, an output interface CN2, an AC relay U1, an AC-to-DC power supply module U2, a control interface CN3, a diode D2, a relay K1 and a relay K2; characterized in that: The two ends of the coil U1.7 of the AC relay U1 are connected one-to-one to the contacts VIN_P and VIN_N of the input interface CN1 respectively; one end of the normally closed contact U1.1 of the AC relay U1 is connected to the contact VIN_P of the input interface CN1, and the other end of the normally closed contact U1.1 of the AC relay U1 is connected to one end of the normally open contact U1.5 of the AC relay U1 to form a first common contact; one end of the normally closed contact U1.2 of the AC relay U1 is connected to the contact VIN_N of the input interface CN1, and the other end of the normally closed contact U1.2 of the AC relay U1 is connected to one end of the normally open contact U1.4 of the AC relay U1 to form a second common contact; The input end of the AC-DC power module U2 is connected to the output end of the input interface CN1, the positive contact of the output end of the AC-DC power module U2 is connected to the other end of the normally open contact U1.5 of the AC relay U1, and the negative contact of the output end of the AC-DC power module U2 is connected to the other end of the normally open contact U1.4 of the AC relay U1; The input end of the control interface CN3 is externally connected to a button switch, the first connection point of the output end of the control interface CN3 is connected to the first common contact, and the second connection point of the output end of the control interface CN3 is respectively connected to the positive electrode of the diode D2 and the positive electrode contact DCOUT+ of the output interface CN2; one end of the coil K1.3 of the relay K1 is connected to the negative electrode of the diode D2, and the other end is connected to the second common contact; one end of the normally open contact K1.2 of the relay K1 is connected to the second common contact, and the other end is connected to the negative electrode contact DCOUT- of the output interface CN2; One end of the relay K2 coil K2.3 is connected to the cathode of the diode D2, and the other end is connected to the second common contact; one end of the normally open contact K2.2 of the relay K2 is connected to the first connection point of the control interface CN3, and the other end is connected to the second connection point of the control interface CN3.

2. A circuit for inputting AC power and outputting DC power according to claim 1, characterized in that: It also includes a filter circuit, which is composed of an energy storage filter capacitor C1. One end of the energy storage filter capacitor C1 is connected to the second wiring point of the control interface CN3, and the other end is connected to the negative electrode of the output interface CN2.

3. The circuit for inputting AC and DC and outputting DC according to claim 1, characterized in that: The AC relay U1 constitutes an AC-DC switching circuit for AC-DC switching; the AC-DC power supply module U2 constitutes an AC-DC power supply circuit for converting AC into DC; the control interface CN3, diode D2 and relay K1 constitute an output control circuit; the relay K2 constitutes an output holding circuit.

4. The circuit for inputting AC power and outputting DC power according to claim 3, characterized in that: The circuit for inputting AC and DC and outputting DC also includes an AC input indication circuit and a DC output indication circuit; The input AC indication circuit is composed of a resistor R3 and a light-emitting diode LED3; one end of the resistor R3 is connected to the negative electrode contact of the output end of the AC-to-DC power module U2, the other end of the resistor R3 is connected to the negative electrode of the light-emitting diode LED3, and the positive electrode of the light-emitting diode LED3 is connected to the positive electrode contact of the output end of the AC-to-DC power module U2; The DC output indication circuit is composed of a resistor R2 and a light-emitting diode LED2; one end of the resistor R2 is connected to the second connection point of the control interface CN3, the other end of the resistor R2 is connected to the positive electrode of the light-emitting diode LED2, and the negative electrode of the light-emitting diode LED2 is connected to the negative electrode of the output interface CN2.

5. The circuit for inputting AC power and outputting DC power according to claim 3, characterized in that: The output control circuit further includes a diode D4 for freewheeling, wherein a cathode of the diode D4 is connected to a cathode of the diode D2, and an anode of the diode D4 is connected to the second common terminal.

6. The circuit for inputting AC and DC and outputting DC according to any one of claims 1 to 5, characterized in that: The power input to the input interface CN1 is direct current or alternating current; the power output from the output interface CN2 is direct current.

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