Transient TTL signal switch control circuit and working method thereof

Abstract

The invention relates to a transient TTL signal switch control circuit and a working method thereof. The circuit comprises a channel opening control unit, a channel closing control unit and a control signal output unit. The channel opening control unit comprises a photoelectric coupler N1; the photoelectric coupler N1 comprises a first light emitting diode and a first phototriode; the channel closing control unit comprises a photoelectric coupler N2; the photoelectric coupler N2 comprises a second light emitting diode and a second phototriode; the control signal output unit comprises a triode V5, a triode V6, a triode V7, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10 and a resistor R11. Compared with a magnetic latching relay control circuit, the magnetic latching relay control circuit not only can realize a channel opening / closing function, but also has the advantages of small driving current, smooth opening / closing instant voltage and current, no peak and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of analog circuits, and in particular to a transient TTL signal switch control circuit and a working method thereof. Background Art

[0002] The magnetic latching relay control circuit is currently widely used in various circuit systems. It is mainly composed of magnetic latching relays and peripheral resistors, diodes and other discrete components. The main function of the magnetic latching relay is to respond to the OC control signal (essentially a transient TTL level) to change the contact position of the contact piece, thereby realizing the channel open circuit / short circuit function.

[0003] In practical applications, some defects of the magnetic latching relay control circuit have gradually emerged. For example, the OC control signal is used to drive the magnetic coil of the relay. Due to the large instantaneous current, if the current capacity of the signal source is insufficient, it is easy for the circuit to fail to respond to the control; the relay coil is highly inductive, and the reverse electromotive force generated when the signal is powered off can easily cause device failure; the relay contact is mechanically contacted, and the jitter of the contact can easily cause transient voltage spikes, etc.

[0004] Therefore, in order to eliminate the above defects, it is necessary to implement a transient TTL signal switch control circuit that is different from the magnetic latching relay control circuit. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide a transient TTL signal switch control circuit and a working method thereof, which can not only realize the channel opening / closing function, but also has the advantages of small driving current, opening / closing instantaneous voltage, smooth current without spikes, etc.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A transient TTL signal switch control circuit comprises a channel opening control unit, a channel closing control unit and a control signal output unit.

[0008] The channel opening control unit includes a photocoupler N1; the photocoupler N1 includes a first light emitting diode and a first photosensitive transistor; the channel closing control unit includes a photocoupler N2; the photocoupler N2 includes a second light emitting diode and a second photosensitive transistor; the control signal output unit includes a transistor V5, a transistor V6, a transistor V7, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10 and a resistor R11.

[0009] The anode of the first light-emitting diode is connected to a resistor R1 and a diode V1; the anode of the diode V1 is connected to a channel-on control level OC_ON, and the cathode of the diode V1 is connected to a first end of the resistor R1; the second end of the resistor R1 is connected to the anode of the first light-emitting diode; the cathode of the first light-emitting diode is connected to a diode V2; the anode of the diode V2 is grounded, and the cathode of the diode V2 is connected to the cathode of the first light-emitting diode.

[0010] The anode of the second light-emitting diode is connected to a resistor R2 and a diode V3; the anode of the diode V3 is connected to the channel closing control level OC_OFF, and the cathode of the diode V3 is connected to the first end of the resistor R2; the second end of the resistor R2 is connected to the anode of the second light-emitting diode; the cathode of the second light-emitting diode is connected to a diode V4; the anode of the diode V4 is connected to the control ground OC_GND, and the cathode of the diode V4 is connected to the cathode of the second light-emitting diode.

[0011] The collector of the first phototransistor is connected to the power supply VCC via the resistor R3. After the emitter of the first phototransistor is connected to the collector of the second phototransistor, it is respectively connected to the first end of the resistor R8 and the base of the transistor V6; the emitter of the second phototransistor receives the control terminal ground GND via the resistor R7; the second end of the resistor R8 is respectively connected to the collector of the transistor V5 and the base of the transistor V7; the base of the transistor V6 receives the control terminal ground GND via the resistor R9, and the collector of the transistor V6 is respectively connected to the resistor R5 via the resistor R6. The first end of the transistor R6 is connected to the base of the transistor V5; the emitter of the transistor V6, the second end of the resistor R10, and the emitter of the transistor V7 are all connected to the controlled end ground GND; the second end of the resistor R5 is respectively connected to the first end of the resistor R4, the emitter of the transistor V5, and the first end of the resistor R11; the second end of the resistor R4 is connected to the power supply VCC; the second end of the resistor R11 is connected to the collector of the transistor V7 as the OC controlled end; the base of the transistor V7 is also connected to the first end of the resistor R10.

[0012] Preferably according to the present invention, the diode V2 is a voltage stabilizing diode.

[0013] Preferably according to the present invention, the transistor V5 is a PNP transistor.

[0014] Preferably according to the present invention, the transistor V6 is an NPN transistor.

[0015] Preferably according to the present invention, the transistor V7 is an NPN transistor.

[0016] Preferably according to the present invention, the supply voltage of the power supply VCC is +12V.

[0017] Preferably according to the present invention, the channel-on control level and the channel-off control level are both transient TTL signals.

[0018] The present invention also includes a working method of the above transient TTL signal switch control circuit, the method comprising the following steps:

[0019] S1. When the transient TTL signal channel-on control level OC_ON acts on the circuit, the CE pole of the first phototransistor in the optocoupler N1 is driven to turn on by light, and the 12V power supply of the power supply VCC drives the CE pole of the NPN transistor V7 to turn on through the resistor R8, so that the OC controlled end is short-connected to the ground; at the same time, the CE pole of the NPN transistor V6 and the EC pole of the PNP transistor V5 are turned on, so that the CE pole of the transistor V7 always remains in the open state after the channel-on control level OC_ON signal completes the control, and the OC controlled end remains in the low level state after the OC_ON signal completes the control.

[0020] S2. When the channel closing control level OC_OFF signal acts on the circuit, the CE pole of the second phototransistor in the photocoupler N2 is driven to turn on by light, and the base voltages of the NPN transistor V5 and the transistor V7 are simultaneously pulled down to the ground, so that the CE poles of the transistors V5 and V7 are closed, and the OC controlled end is flipped to a high level; at the same time, since the CE pole of the transistor V6 is closed, the EC pole of the PNP transistor V7 becomes closed. After the OC_OFF signal completes the control, since there are no other control signals, the OC controlled end maintains a high level state.

[0021] Compared with the prior art, the advantages of the present invention are:

[0022] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide a transient TTL signal switch control circuit and a working method thereof which are different from the magnetic latching relay control circuit. The control circuit is mainly composed of a photocoupler, a transistor, a diode and a resistor. Its main function is that the output transistor responds to the transient OC level of the input terminal, and its CE pole correspondingly maintains the on / open state, thereby realizing the channel opening / closing function. Compared with the magnetic latching relay control circuit, the present invention can not only realize the channel opening / closing function, but also has the advantages of small driving current, opening / closing instantaneous voltage, and current smoothness without spikes.

[0023] The main innovation of the switch control circuit of the present invention is that it realizes the function of responding to the OC control signal and maintaining the channel opening / closing, but does not contain a magnetic latching relay circuit, and realizes the functional replacement of the magnetic latching relay circuit. Magnetic latching relays are often used to realize channel opening and closing in circuit systems, but due to the inherent defects of the internal structure of the device, it is easy to fail due to excessive instantaneous driving current, causing components such as resistors to burn out, and voltage jitter generated by contact of the contact piece to damage the chip. After the magnetic latching relay caused system function failure many times, some high-reliability projects have begun to prohibit the use of magnetic latching relays, so it is imperative to design a replacement circuit. Compared with the magnetic latching relay circuit, the switch control circuit of the present invention completely avoids the shortcomings while fully realizing its functions. At the signal driving end, the inductor coil drive used by the magnetic latching relay is replaced by optical drive, which greatly reduces the instantaneous driving current; at the switch control end, the contact piece contact / separation of the magnetic latching relay is replaced by the short circuit / open circuit of the transistor electrode. Moreover, since the control of the channel switch by this circuit does not contain mechanical movement, the voltage and current are smooth at the moment of channel opening / closing, thereby avoiding the damage to the system caused by the voltage and current fluctuations generated at the moment of contact piece state conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a circuit schematic diagram of the transient TTL signal switch control circuit in the present invention;

[0025] Figure 2 It is a simulation diagram of the transient TTL signal switch control circuit in the present invention, wherein the horizontal axis is time, each grid is 0.2s, and the vertical axis is voltage, each grid is 5V. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings:

[0027] like Figure 1 A transient TTL signal switch control circuit is shown, the circuit includes a channel opening control unit, a channel closing control unit and a control signal output unit. Figure 1 In the circuit, OC_ON is the channel opening control level, OC_OFF is the channel closing control level, OC_GND is the control ground, VCC is the 12V power supply terminal, and GND is the controlled terminal ground. The channel opening control level OC_ON and the channel closing control level OC_OFF are both transient TTL signals. The main innovation of this circuit is the invention of a circuit that responds to the OC control signal to maintain the channel opening / closing function, but does not contain a magnetic latching relay, thus realizing the functional replacement of the magnetic latching relay circuit.

[0028] The channel opening control unit includes a photocoupler N1; the photocoupler N1 includes a first light emitting diode and a first photosensitive transistor. The channel closing control unit includes a photocoupler N2; the photocoupler N2 includes a second light emitting diode and a second photosensitive transistor. The control signal output unit includes a transistor V5, a transistor V6, a transistor V7, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10 and a resistor R11. Among them, the photocoupler N1 and the photocoupler N2 are used to achieve drive and switch isolation and optical drive. The transistor V5, the transistor V6 and the transistor V7 are used to achieve switch control and state retention. The resistor R1, the resistor R2, the resistor R3, the resistor R4 and the resistor R7 are used to achieve current limitation. The resistor R5, the resistor R6, the resistor R8, the resistor R9 and the resistor R10 are used to achieve voltage retention.

[0029] The anode of the first light-emitting diode is connected to a resistor R1 and a diode V1; the anode of the diode V1 is connected to a channel-on control level OC_ON, and the cathode of the diode V1 is connected to a first end of the resistor R1; the second end of the resistor R1 is connected to the anode of the first light-emitting diode; the cathode of the first light-emitting diode is connected to a diode V2; the anode of the diode V2 is grounded, and the cathode of the diode V2 is connected to the cathode of the first light-emitting diode.

[0030] The collector of the first phototransistor is connected to the power supply VCC via the resistor R3. After the emitter of the first phototransistor is connected to the collector of the second phototransistor, it is respectively connected to the first end of the resistor R8 and the base of the transistor V6; the emitter of the second phototransistor receives the control terminal ground GND via the resistor R7; the second end of the resistor R8 is respectively connected to the collector of the transistor V5 and the base of the transistor V7; the base of the transistor V6 receives the control terminal ground GND via the resistor R9, and the collector of the transistor V6 is respectively connected to the resistor R5 via the resistor R6. The first end of the transistor R6 is connected to the base of the transistor V5; the emitter of the transistor V6, the second end of the resistor R10, and the emitter of the transistor V7 are all connected to the controlled end ground GND; the second end of the resistor R5 is respectively connected to the first end of the resistor R4, the emitter of the transistor V5, and the first end of the resistor R11; the second end of the resistor R4 is connected to the power supply VCC; the second end of the resistor R11 is connected to the collector of the transistor V7 as the OC controlled end; the base of the transistor V7 is also connected to the first end of the resistor R10.

[0031] The anode of the second light-emitting diode is connected to a resistor R2 and a diode V3; the anode of the diode V3 is connected to the channel closing control level OC_OFF, and the cathode of the diode V3 is connected to the first end of the resistor R2; the second end of the resistor R2 is connected to the anode of the second light-emitting diode; the cathode of the second light-emitting diode is connected to a diode V4; the anode of the diode V4 is connected to the control ground OC_GND, and the cathode of the diode V4 is connected to the cathode of the second light-emitting diode.

[0032] Furthermore, the diode V2 is a voltage regulator diode.

[0033] Furthermore, the transistor V5 is a PNP transistor.

[0034] Furthermore, the transistor V6 is an NPN transistor.

[0035] Furthermore, the transistor V7 is an NPN transistor.

[0036] Furthermore, the supply voltage of the power supply VCC is +12V.

[0037] Furthermore, the channel-on control level and the channel-off control level are both transient TTL signals.

[0038] The working method of the above transient TTL signal switch control circuit is:

[0039] When the transient TTL signal OC_ON acts on the circuit after being unidirectionally isolated by diode V1, the CE pole of the first photosensitive transistor in the photocoupler N1 is driven to turn on by light, and the resistor R1 limits the driving current to a lower level. The voltage regulator V2 is used to provide a threshold for light driving to reduce the probability of the circuit being falsely triggered by external noise. The 12V power supply of the power supply VCC drives the CE pole of the NPN transistor V7 to turn on through the resistor R8, so that the OC controlled end is shorted to the ground, and the CE pole of the NPN transistor V6 and the EC pole of the PNP transistor V5 are also turned on, so that the CE pole of the transistor V7 always remains in the open state after the channel opening control level OC_ON signal completes the control, and the OC controlled end remains in the low level state after the OC_ON signal completes the control. In this process, resistors R3, R4, R7 and R11 are used to limit the current of the transistor circuit, resistors R5 and R6 form a resistor voltage divider circuit to provide a turn-on voltage for transistor V5, resistor R9 is used to maintain the base voltage of transistor V6, and resistor R10 is used to maintain the base voltage of transistor V7.

[0040] When the OC_OFF signal acts on the circuit after being unidirectionally isolated by diode V3, the CE pole of the second photosensitive transistor in the photocoupler N2 is turned on by light drive, and the resistor R2 limits the driving current to a lower level. The voltage regulator V4 is used to provide a threshold for light drive to reduce the probability of the circuit being falsely triggered by external noise. The base voltages of the NPN transistor V5 and the transistor V7 are simultaneously pulled down to ground, and the CE poles of the transistors V5 and V7 are therefore turned off, and the OC controlled end is flipped to a high level. At the same time, since the CE pole of the transistor V6 is turned off, the EC pole of the PNP transistor V7 becomes closed. After the OC_OFF signal completes the control, since there is no other control signal, the OC controlled end remains in a high level state. In this process, resistors R3, R4 and R11 are used to limit the current of the transistor circuit; resistor R7 is used to discharge the emitter voltage of the photocoupler N2. Since the collector-emitter of transistor V6 is closed, resistor R6 is suspended and loses its function. When the VCC voltage enters the base of transistor V5 through resistor R5, transistor V5 is closed. Resistor R9 is used to discharge the base voltage of transistor V6. Resistor R10 is used to discharge the base voltage of transistor V7.

[0041] like Figure 2 As shown, the switch control circuit of the present invention was subjected to circuit simulation during the design stage. Figure 2 A is the OC on pulse voltage, B is the OC off pulse voltage, and C is the base voltage of transistor V7. It can be seen from the simulation waveform that after the OC on or off pulse is completed, the base voltage of transistor V7 can maintain the state, and the level polarity is consistent with the design. The circuit design is effective. The circuit described in the present invention has been actually installed in a certain aerospace project and is working on orbit, and the state is normal.

[0042] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the scope of protection determined by the claims of the present invention.

Claims

1. A transient TTL signal switch control circuit, characterized in that: The circuit includes a channel opening control unit, a channel closing control unit and a control signal output unit; The channel opening control unit includes a photocoupler N1; the photocoupler N1 includes a first light emitting diode and a first photosensitive transistor; the channel closing control unit includes a photocoupler N2; the photocoupler N2 includes a second light emitting diode and a second photosensitive transistor; the control signal output unit includes a transistor V5, a transistor V6, a transistor V7, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10 and a resistor R11; The anode of the first light-emitting diode is connected to a resistor R1 and a diode V1; the anode of the diode V1 is connected to the channel-on control level OC_ON, and the cathode of the diode V1 is connected to the first end of the resistor R1; the second end of the resistor R1 is connected to the anode of the first light-emitting diode; the cathode of the first light-emitting diode is connected to a diode V2; the anode of the diode V2 is grounded, and the cathode of the diode V2 is connected to the cathode of the first light-emitting diode; The anode of the second light-emitting diode is connected to a resistor R2 and a diode V3; the anode of the diode V3 is connected to the channel closing control level OC_OFF, and the cathode of the diode V3 is connected to the first end of the resistor R2; the second end of the resistor R2 is connected to the anode of the second light-emitting diode; the cathode of the second light-emitting diode is connected to a diode V4; the anode of the diode V4 is connected to the control ground OC_GND, and the cathode of the diode V4 is connected to the cathode of the second light-emitting diode; The collector of the first phototransistor is connected to the power supply VCC via the resistor R3. After the emitter of the first phototransistor is connected to the collector of the second phototransistor, it is respectively connected to the first end of the resistor R8 and the base of the transistor V6; the emitter of the second phototransistor receives the control terminal ground GND via the resistor R7; the second end of the resistor R8 is respectively connected to the collector of the transistor V5 and the base of the transistor V7; the base of the transistor V6 receives the control terminal ground GND via the resistor R9, and the collector of the transistor V6 is respectively connected to the resistor R5 via the resistor R6. The first end of the transistor R6 is connected to the base of the transistor V5; the emitter of the transistor V6, the second end of the resistor R10, and the emitter of the transistor V7 are all connected to the controlled end ground GND; the second end of the resistor R5 is respectively connected to the first end of the resistor R4, the emitter of the transistor V5, and the first end of the resistor R11; the second end of the resistor R4 is connected to the power supply VCC; the second end of the resistor R11 is connected to the collector of the transistor V7 as the OC controlled end; the base of the transistor V7 is also connected to the first end of the resistor R10.

2. The transient TTL signal switch control circuit according to claim 1, characterized in that: The diode V2 is a voltage stabilizing diode.

3. The transient TTL signal switch control circuit according to claim 1, characterized in that: The transistor V5 is a PNP transistor.

4. The transient TTL signal switch control circuit according to claim 1, characterized in that: The transistor V6 is an NPN transistor.

5. The transient TTL signal switch control circuit according to claim 1, characterized in that: The transistor V7 is an NPN transistor.

6. The transient TTL signal switch control circuit according to claim 1, characterized in that: The supply voltage of the power supply VCC is +12V.

7. The transient TTL signal switch control circuit according to claim 1, characterized in that: The channel-on control level and the channel-off control level are both transient TTL signals.

8. The operating method of the transient TTL signal switch control circuit according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: S1. When the transient TTL signal channel-on control level OC_ON acts on the circuit, the CE pole of the first photosensitive transistor in the photocoupler N1 is driven to turn on by light, and the 12V power supply of the power supply VCC drives the CE pole of the NPN transistor V7 to turn on through the resistor R8, so that the OC controlled end is short-connected to the ground; at the same time, the CE pole of the NPN transistor V6 and the EC pole of the PNP transistor V5 are turned on, so that the CE pole of the transistor V7 always remains in the open state after the channel-on control level OC_ON signal completes the control, and the OC controlled end remains in the low level state after the OC_ON signal completes the control; S2. When the channel closing control level OC_OFF signal acts on the circuit, the CE pole of the second phototransistor in the photocoupler N2 is driven to turn on by light, and the base voltages of the NPN transistor V5 and the transistor V7 are simultaneously pulled down to the ground, so that the CE poles of the transistors V5 and V7 are closed, and the OC controlled end is flipped to a high level; at the same time, since the CE pole of the transistor V6 is closed, the EC pole of the PNP transistor V7 becomes closed. After the OC_OFF signal completes the control, since there are no other control signals, the OC controlled end maintains a high level state.

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