Cooling fan control circuit of intercom equipment, intercom power cord and intercom equipment

Abstract

The present invention provides a cooling fan control circuit of an intercom device, an intercom power line and an intercom device. The cooling fan control circuit includes a power input end, a signal generating circuit, a main control circuit, a driving circuit and a cooling fan interface. The power input end provides power to the signal generating circuit, the main control circuit, the driving circuit and the cooling fan interface. The signal generating circuit includes a comparator, the first input end of the comparator and the second input end of the comparator are both electrically connected to the power input end, the first input end of the comparator is connected in parallel with a first capacitor, and the output end of the comparator is electrically connected to the main control circuit. The main control circuit is electrically connected to the driving circuit, and the driving circuit is electrically connected to the cooling fan interface. The intercom power line applies the cooling fan control circuit. The intercom device applies the intercom device. The intercom device applying the present invention has high control sensitivity and saves energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation of intercom equipment, and in particular to a heat dissipation fan control circuit of the intercom equipment, an intercom power line using the heat dissipation fan control circuit, and an intercom equipment using the intercom power line. Background Art

[0002] The car walkie-talkie or base walkie-talkie requires less current when receiving, but requires higher power when sending signals. The power of a general car walkie-talkie is 50 watts. The power module of the walkie-talkie is prone to heat up. Therefore, a cooling fan is required to dissipate heat to prevent the walkie-talkie from burning.

[0003] However, when the existing intercom controls the cooling fan to work, as long as the intercom is turned on, the cooling fan is controlled to work, and no control is performed according to the working condition of the power module, resulting in a waste of power. Moreover, some intercoms do not have a built-in cooling fan, which is inconvenient when a cooling fan needs to be installed. Summary of the invention

[0004] The first object of the present invention is to provide a cooling fan control circuit for an intercom device with high control sensitivity.

[0005] The second object of the present invention is to provide a walkie-talkie power cord with high control sensitivity and convenient for externally connecting a cooling fan.

[0006] The third object of the present invention is to provide an intercom device with high control sensitivity and energy saving.

[0007] In order to achieve the above-mentioned first purpose, the cooling fan control circuit of the intercom device provided by the present invention includes a power input end, a signal generating circuit, a main control circuit, a drive circuit and a cooling fan interface, the power input end provides power to the signal generating circuit, the main control circuit, the drive circuit and the cooling fan interface; the signal generating circuit includes a comparator, the first input end of the comparator and the second input end of the comparator are both electrically connected to the power input end, the first input end of the comparator is connected in parallel with a first capacitor, and the output end of the comparator is electrically connected to the main control circuit; the main control circuit is electrically connected to the drive circuit, and the drive circuit is electrically connected to the cooling fan interface.

[0008] It can be seen from the above scheme that the signal generating circuit of the cooling fan control circuit of the present invention is provided with a comparator, and the first input end of the comparator and the second input end of the comparator are both electrically connected to the power input end, and the first input end of the comparator is connected in parallel with a first capacitor. When the voltage of the power input end is reduced, since the first input end is connected in parallel with the first capacitor, a voltage difference is formed between the first input end and the second input end of the comparator, and the comparator amplifies the voltage difference and transmits it to the main control circuit, so that the main control circuit can control the drive circuit to drive the cooling fan electrically connected to the cooling fan interface to dissipate heat. By setting the comparator to send the control signal, the voltage change can be detected and the control sensitivity can be improved.

[0009] In a further solution, a diode is provided in the path between the output end of the comparator and the main control circuit, the cathode of the diode is electrically connected to the output end of the comparator, and the anode of the diode is electrically connected to the main control circuit.

[0010] It can be seen that by setting a diode, the cathode of the diode is electrically connected to the output end of the comparator, and the anode of the diode is electrically connected to the main control circuit. The diode obtains the voltage at the output end of the comparator to open the path between the output end of the comparator and the main control circuit, so that the main control circuit can obtain the control signal.

[0011] In a further solution, the driving circuit includes a PNP transistor and an NPN transistor, the base of the PNP transistor is electrically connected to the main control circuit, the collector of the PNP transistor is electrically connected to the base of the NPN transistor, and the collector of the NPN transistor is electrically connected to the cooling fan interface.

[0012] It can be seen that the sensitivity of the transistor is relatively high. By setting a PNP transistor and an NPN transistor as the driving circuit, the sensitivity of the driving circuit control is improved.

[0013] In a further solution, a first pull-up resistor is connected in series on a branch between the first input terminal and the power input terminal; a second pull-up resistor is connected in series on a branch between the second input terminal and the power input terminal; and the first pull-up resistor and the second pull-up resistor have the same resistance value.

[0014] In a further scheme, a first pull-down resistor is connected in parallel to the first input terminal, a first end of the first pull-down resistor is electrically connected to the first input terminal, and a second end of the first pull-down resistor is grounded; a second pull-down resistor is connected in parallel to the second input terminal, a first end of the second pull-down resistor is electrically connected to the first input terminal, and a second end of the second pull-down resistor is grounded; the first pull-down resistor and the second pull-down resistor have the same resistance value.

[0015] It can be seen that the first pull-up resistor, the second pull-up resistor, the first pull-down resistor and the second pull-down resistor are set, the first pull-up resistor and the second pull-up resistor have the same resistance value, and the first pull-down resistor and the second pull-down resistor have the same resistance value, so that when the input voltage of the power input terminal is normal, no voltage difference is formed between the first input terminal and the second input terminal.

[0016] In a further solution, a first filter circuit is provided in the path between the cooling fan interface and the power input terminal, the input terminal of the first filter circuit is electrically connected to the power input terminal, and the output terminal of the first filter circuit is electrically connected to the positive pole of the cooling fan interface.

[0017] In a further solution, the first filter circuit is an RC filter circuit.

[0018] It can be seen that the path between the cooling fan interface and the power input terminal is provided with a first filtering circuit, which can filter out the AC part of the input voltage of the power input terminal, so that the control of the cooling fan interface is more stable.

[0019] In a further scheme, a step-down circuit and a second filter circuit are arranged on the path between the power supply terminal and the power supply input terminal of the main control circuit, the input terminal of the step-down circuit is electrically connected to the power supply input terminal, the output terminal of the step-down circuit is electrically connected to the input terminal of the second filter circuit, and the output terminal of the second filter circuit is electrically connected to the power supply terminal of the main control circuit.

[0020] In order to achieve the above-mentioned second purpose, the walkie-talkie power cord provided by the present invention includes a power interface, an intercom interface and a cooling fan control circuit, the power interface is electrically connected to the intercom interface; the cooling fan control circuit applies the above-mentioned cooling fan control circuit; the power input end of the cooling fan control circuit is connected in parallel to the path between the power interface and the intercom interface.

[0021] As can be seen from the above scheme, in the intercom power line of the present invention, the signal generating circuit of the cooling fan control circuit is provided with a comparator, the first input end of the comparator and the second input end of the comparator are both electrically connected to the power input end, the first input end of the comparator is connected in parallel with a first capacitor, when the voltage of the power input end is reduced, due to the first input end being connected in parallel with the first capacitor, a pressure difference is formed between the first input end and the second input end of the comparator, the comparator amplifies the pressure difference and transmits it to the main control circuit, so that the main control circuit can control the driving circuit to drive the cooling fan for heat dissipation, and by providing a comparator to send a control signal, the voltage change can be detected, and the control sensitivity can be improved. At the same time, providing a cooling fan interface can facilitate the external cooling fan, and heat the intercom device that is not provided with a cooling fan. And providing a power interface and an intercom interface can facilitate disassembly and assembly.

[0022] In order to achieve the above-mentioned third purpose, the intercom equipment provided by the present invention includes a power supply, an intercom control circuit, an intercom power cord and a cooling fan, and the intercom power cord uses the above-mentioned intercom power cord; the power supply is electrically connected to the power interface, the intercom interface is electrically connected to the intercom control circuit, and the cooling fan interface is electrically connected to the cooling fan.

[0023] As can be seen from the above scheme, in the intercom device of the present invention, the signal generating circuit of the cooling fan control circuit is provided with a comparator, the first input end of the comparator and the second input end of the comparator are both electrically connected to the power input end, the first input end of the comparator is connected in parallel with a first capacitor, the power input end of the cooling fan control circuit is connected in parallel to the path between the power supply and the intercom control circuit, when the intercom control circuit sends a signal, due to the tidal effect of electricity, the voltage of the power input end will decrease, because the first input end is connected in parallel with the first capacitor, resulting in a pressure difference between the first input end and the second input end of the comparator, the comparator amplifies the pressure difference and transmits it to the main control circuit, so that the main control circuit can control the driving circuit to drive the cooling fan to dissipate heat, and by setting the comparator to send the control signal, the voltage change can be detected, and the sensitivity of the control can be improved. In addition, the cooling fan is controlled to dissipate heat only when the intercom control circuit sends a signal, thereby saving energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a circuit structure block diagram of an embodiment of a walkie-talkie power line of the present invention.

[0025] Figure 2 The invention discloses a circuit schematic diagram of a heat dissipation fan control circuit in an embodiment of a power cord of an intercom.

[0026] Figure 3 It is a circuit structure block diagram of an intercom device embodiment of the present invention.

[0027] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0028] Intercom power cord example:

[0029] like Figure 1 As shown, in this embodiment, the intercom power line includes a power interface 1, an intercom interface 2 and a cooling fan control circuit 3, the power interface 1 is electrically connected to the intercom interface 2, and the cooling fan control circuit 3 is connected in parallel to the path between the power interface 1 and the intercom interface 2.

[0030] See also Figure 2The cooling fan control circuit 3 includes a power input terminal 31, a signal generating circuit 32, a main control circuit U1, a driving circuit 33 and a cooling fan interface 34. The power input terminal 31 is connected in parallel to the path between the power interface 1 and the intercom interface 2. The power input terminal 31 provides power to the signal generating circuit 32, the main control circuit U1, the driving circuit 33 and the cooling fan interface 34. Preferably, the main control circuit U1 adopts a single chip microcomputer of the AT89C2051 model.

[0031] The signal generating circuit 32 includes a comparator U2. Preferably, the comparator U2 is a LM393 comparator. The first input terminal of the comparator U2 and the second input terminal of the comparator U2 are both electrically connected to the power input terminal 31. The main control circuit U1 is electrically connected to the drive circuit 33, and the drive circuit 33 is electrically connected to the cooling fan interface 34.

[0032] The first input terminal of the comparator U2 is connected in parallel with a first capacitor C1, the first end of the first capacitor C1 is electrically connected to the first input terminal, and the second end of the first capacitor C1 is grounded. In this embodiment, the first capacitor C1 is a capacitor of 1000μF. A first pull-up resistor R1 is connected in series on a branch between the first input terminal of the comparator U2 and the power input terminal 31, and a second pull-up resistor R2 is connected in series on a branch between the second input terminal of the comparator U2 and the power input terminal 31. The resistance values ​​of the first pull-up resistor and the second pull-up resistor are the same. The first input terminal is also connected in parallel with a first pull-down resistor R3, the first end of the first pull-down resistor R3 is electrically connected to the first input terminal, and the second end of the first pull-down resistor R3 is grounded. The second input terminal is connected in parallel with a second pull-down resistor R4, the first end of the second pull-down resistor R4 is electrically connected to the first input terminal, and the second end of the second pull-down resistor R4 is grounded. The resistance values ​​of the first pull-down resistor R3 and the second pull-down resistor R4 are the same.

[0033] In this embodiment, the signal generating circuit 32 also includes a resistor R5 and a capacitor C2. The first pull-up resistor R1 and the second pull-up resistor R2 are both electrically connected to the power input terminal 31 through the resistor R5. The capacitor C2 is connected in parallel to the path between the resistor R5 and the first pull-up resistor R1 and the second pull-up resistor R2.

[0034] The output end of the comparator U2 is electrically connected to the main control circuit U1. In this embodiment, a diode D1 is provided in the path between the output end of the comparator U2 and the main control circuit U1. The cathode of the diode D1 is electrically connected to the output end of the comparator U2, the anode of the diode D1 is electrically connected to the main control circuit U1, and the output end of the comparator U2 is also electrically connected to the power input end 31 through the resistor R6. Preferably, the diode D1 is a diode of model IN4001.

[0035] The path between the cooling fan interface 34 and the power input terminal 31 is provided with a first filter circuit 35, the input terminal of the first filter circuit 35 is electrically connected to the power input terminal 31, and the output terminal of the first filter circuit 35 is electrically connected to the positive electrode of the cooling fan interface 34. In this embodiment, the first filter circuit 35 is an RC filter circuit. The first filter circuit 35 includes a resistor R7, a capacitor C3 and a capacitor C4, a first end of the resistor R7 is electrically connected to the power input terminal 31, a second end of the resistor R7 is electrically connected to the positive electrode of the cooling fan interface 34, a first end of the capacitor C3 is electrically connected to the second end of the resistor R7, a second end of the capacitor C3 is grounded, a first end of the capacitor C4 is electrically connected to the second end of the resistor R7, and a second end of the capacitor C4 is grounded.

[0036] A step-down circuit U3 and a second filter circuit 36 ​​are provided on the path between the power supply end and the power supply input end 31 of the main control circuit U1, the input end of the step-down circuit U3 is electrically connected to the power supply input end 31, the output end of the step-down circuit U3 is electrically connected to the input end of the second filter circuit 36, and the output end of the second filter circuit 36 ​​is electrically connected to the power supply end of the main control circuit U1. In this embodiment, the second filter circuit 36 ​​is a capacitor filter circuit. The second filter circuit 36 ​​includes a capacitor C5 and a capacitor C6, the first end of the capacitor C5 is electrically connected to the output end of the step-down circuit U3, the second end of the capacitor C5 is grounded, the first end of the capacitor C6 is electrically connected to the output end of the step-down circuit U3, and the second end of the capacitor C6 is grounded. Preferably, the step-down circuit U3 adopts a 7805 three-terminal voltage regulator integrated circuit.

[0037] The driving circuit 33 includes a PNP transistor Q1 and an NPN transistor Q2. The base of the PNP transistor Q1 is electrically connected to the main control circuit U1 through a resistor R8, the collector of the PNP transistor Q1 is electrically connected to the base of the NPN transistor Q2, the emitter of the PNP transistor Q1 is electrically connected to the output end of the second filter circuit 36 ​​through a resistor R9, the collector of the NPN transistor Q2 is electrically connected to the negative electrode of the cooling fan interface 34, and the emitter of the NPN transistor Q2 is grounded.

[0038] Intercom equipment embodiment:

[0039] like Figure 3As shown, the intercom device of this embodiment includes an intercom power cord 10, a power supply 20, an intercom control circuit 30 and a cooling fan 40. The intercom power cord 10 applies the intercom power cord in the above intercom power cord embodiment. The power supply 20 is electrically connected to the power interface 1, the intercom interface 2 is electrically connected to the intercom control circuit 30, and the cooling fan interface 34 is electrically connected to the cooling fan 40. The power supply 20 provides power to the intercom control circuit 30 and the cooling fan 40. In this embodiment, the power supply 20 is connected to the power interface 1 in a plug-in manner, the intercom interface 2 is connected to the intercom control circuit 30 in a plug-in manner, and the cooling fan interface 34 is connected to the cooling fan 40 in a plug-in manner.

[0040] When the intercom device of the present invention is in the turned-on state, the power supply 20 provides power to the intercom control circuit 30. When no signal is sent, the power loss of the intercom control circuit 30 is low, the voltage of the power input terminal 31 does not change significantly, and there is no voltage difference between the first input terminal of the comparator U2 and the second input terminal of the comparator U2. At this time, the positive end of the diode D1 is 5V, and the negative end is 13.8V. The diode D1 is cut off, and the main control circuit U1 sends a high level to the PNP transistor Q1. The PNP transistor Q1 and the NPN transistor Q2 are in the cut-off state, and the cooling fan 40 stops running. When the intercom device sends a signal, the power loss of the intercom control circuit 30 increases. Due to the tidal effect of electricity, the voltage of the power input terminal 31 will decrease. Since the first input terminal of the comparator U2 is connected in parallel with the first capacitor C1, the first capacitor C1 stores electrical energy, and the voltage of the first input terminal of the comparator U2 drops slowly, resulting in a voltage difference between the first input terminal and the second input terminal of the comparator U2. The comparator U2 outputs a low voltage, and the diode D1 is forward-conducted, so that the diode D1 turns on the path between the output terminal of the comparator U2 and the main control circuit U1. The main control circuit U1 obtains a control signal, and the main control circuit U1 sends a low level to the PNP transistor Q1. The PNP transistor Q1 and the NPN transistor Q2 are in the on state, and the cooling fan 40 starts to dissipate heat.

[0041] It should be noted that the driving circuit 33 of the present invention can adopt not only the triode circuit structure in this embodiment but also a relay switch circuit structure. The relay switch circuit is a technology well known to those skilled in the art and will not be described in detail here.

[0042] As can be seen from the above, in the intercom device of the present invention, the signal generating circuit of the cooling fan control circuit is provided with a comparator, and the first input terminal of the comparator and the second input terminal of the comparator are both electrically connected to the power input terminal, and the first input terminal of the comparator is connected in parallel with a first capacitor, and the power input terminal of the cooling fan control circuit is connected in parallel to the path between the power circuit and the intercom control circuit. When the intercom control circuit sends a signal, the voltage of the power input terminal will decrease due to the tidal effect of electricity. Since the first input terminal is connected in parallel with the first capacitor, a pressure difference is formed between the first input terminal and the second input terminal of the comparator. The comparator amplifies the pressure difference and transmits it to the main control circuit, so that the main control circuit can control the drive circuit to drive the cooling fan for heat dissipation. By setting the comparator to send the control signal, the voltage change can be detected and the control sensitivity can be improved.

[0043] It should be noted that the above are only preferred embodiments of the present invention, but the design concept of the invention is not limited thereto, and any non-substantial modifications made to the present invention using this concept also fall within the protection scope of the present invention.

Claims

1. A cooling fan control circuit for an intercom device, characterized in that: It includes a power input terminal, a signal generating circuit, a main control circuit, a driving circuit and a cooling fan interface, wherein the power input terminal provides power to the signal generating circuit, the main control circuit, the driving circuit and the cooling fan interface; The signal generating circuit comprises a comparator, wherein a first input terminal of the comparator and a second input terminal of the comparator are both electrically connected to the power input terminal, a first capacitor is connected in parallel to the first input terminal of the comparator, and an output terminal of the comparator is electrically connected to the main control circuit; The main control circuit is electrically connected to the drive circuit, and the drive circuit is electrically connected to the cooling fan interface; A diode is provided in the path between the output end of the comparator and the main control circuit, the cathode of the diode is electrically connected to the output end of the comparator, and the anode of the diode is electrically connected to the main control circuit; The driving circuit comprises a PNP transistor and an NPN transistor, the base of the PNP transistor is electrically connected to the main control circuit, the collector of the PNP transistor is electrically connected to the base of the NPN transistor, and the collector of the NPN transistor is electrically connected to the cooling fan interface; A first pull-up resistor is connected in series on the branch between the first input terminal and the power input terminal; A second pull-up resistor is connected in series on the branch between the second input terminal and the power input terminal; The first pull-up resistor and the second pull-up resistor have the same resistance value.

2. The cooling fan control circuit of the intercom device according to claim 1, characterized in that: The first input terminal is connected in parallel with a first pull-down resistor, a first end of the first pull-down resistor is electrically connected to the first input terminal, and a second end of the first pull-down resistor is grounded; The second input terminal is connected in parallel with a second pull-down resistor, a first end of the second pull-down resistor is electrically connected to the first input terminal, and a second end of the second pull-down resistor is grounded; The first pull-down resistor and the second pull-down resistor have the same resistance value.

3. The cooling fan control circuit of the intercom device according to claim 1, characterized in that: A first filter circuit is provided in the path between the cooling fan interface and the power input end, the input end of the first filter circuit is electrically connected to the power input end, and the output end of the first filter circuit is electrically connected to the positive pole of the cooling fan interface.

4. The cooling fan control circuit of the intercom device according to claim 3, characterized in that: The first filter circuit is an RC filter circuit.

5. The cooling fan control circuit of the intercom device according to claim 1, characterized in that: A step-down circuit and a second filter circuit are provided on the path between the power supply end and the power supply input end of the main control circuit, the input end of the step-down circuit is electrically connected to the power supply input end, the output end of the step-down circuit is electrically connected to the input end of the second filter circuit, and the output end of the second filter circuit is electrically connected to the power supply end of the main control circuit.

6. A walkie-talkie power cord, characterized in that: It includes a power interface, an intercom interface and a cooling fan control circuit, wherein the power interface is electrically connected to the intercom interface; The cooling fan control circuit applies the cooling fan control circuit according to any one of claims 1 to 5; The power input end of the cooling fan control circuit is connected in parallel to the path between the power interface and the intercom interface.

7. An intercom device, comprising a power supply, an intercom control circuit, an intercom power cord and a cooling fan, characterized in that: The intercom power cord applies the intercom power cord according to claim 6; The power supply is electrically connected to the power supply interface, the intercom interface is electrically connected to the intercom control circuit, and the cooling fan interface is electrically connected to the cooling fan.

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