JP2618572B2 - High frequency relay switching circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency relay switching circuit applied to radio equipment and the like, and more particularly to control of a relay for switching a high-frequency signal.

In recent years, wireless devices used for telephone calls and the like have been required to have high reliability, low cost, small size and light weight. In this case, in a high-frequency relay opening / closing circuit for supplying a high frequency generated only at the time of transmission to the antenna, the relay contact deteriorates when a chattering operation occurs while a high-frequency signal is applied.
It is necessary to control the stop timing and the switching timing of the relay sequentially to protect the relay contact.

In order to perform reliable sequence control without deteriorating relay contacts and the like, it is only necessary to use high-cost and large-sized components such as a CPU. Cannot be used, so that reliable sequence control cannot be realized, and eventually the relay contacts and the like are deteriorated. As described above, there is a disadvantage that any one of the plurality of requests has to be sacrificed.

Therefore, a circuit that reliably controls the timing of generating / stopping a high frequency and the timing of opening / closing a relay without using a CPU or the like has become useful.

[0005]

2. Description of the Related Art FIG. 5 is a diagram showing a conventional high frequency relay switching circuit, which controls a high frequency signal switching relay using a press signal output from a transmission button provided on a microphone of a wireless device. is there.

[0006] Reference numeral 51 denotes a transmitter for generating a high frequency, which is connected to an antenna via a relay 52. Relay 52
Indicates that when no current is flowing through the coil,
The antenna is connected to the b side, and an antenna and a wireless receiving circuit are connected to configure a receiving state. When the coil is energized from the relay drive unit 54 and the contact is switched to the 52a side, the transmission unit 51 and the antenna are connected, and the transmission state is configured.

[0007] The relay driving section 54 is a coil of the relay 52.
Transistor Tr that passes current through_ThreeAnd press signal 58
Input and transistor Tr_ThreeTurn on transistor
Tr _FourAnd the bias resistor R_FourConsists of

[0008] From delays the press signal 58, the delay circuit 55 for outputting a power control signal 57 of the high frequency generator (i.e. transmitting unit 51), the resistor R ₂ and capacitor C on the delay effect when you press the send button _1, and a resistor R ₁ in order to discharge the charge stored in the capacitor C ₁ when releasing the send button.

The power switch 53 of the transmitting section 51 includes a transistor Tr ₁ for supplying power to the transmitting section 51, a transistor Tr ₂ for inputting a power control signal 57 and turning on the transistor Tr ₁ , and a bias resistor R _3. Be composed.

FIG. 6 is a time chart for explaining the operation of the conventional high-frequency relay switching circuit of FIG.

[0011] When pressing the send button radio, press signal 58 turns on the transistor Tr _4, the transistor Tr ₄ is to turn on the transistor Tr _3, resulting in a current flows to the coil of the relay 52, relay 52 The contact of (5) causes a chattering operation for a while and is switched from the 52b side to the 52a side. Thereafter, the transmission unit 51 and the antenna are stabilized in a connected state.

Meanwhile, after a time determined by the constant C ₁ R ₂ when the press signal 58 has elapsed, turns on transistor Tr _2, the transistor Tr ₂ is to turn on the transistor Tr _1, the send button as a result After the time determined by the time constant C ₁ R ₂ elapses from the pressing, power is supplied to the transmission unit 51, and the high-frequency signal 56 is transmitted to the transmission unit 51.
Output from

The above sequence will be described with reference to a time chart of FIG. When a transmission signal is pressed by pressing the transmission button of the wireless device as shown in, a relay driving current flows as in, and the relay contact causes chattering as in. On the other hand, the time constant C ₁ R ₂
After the elapse of the time determined by, the transmission unit power supply is turned on as in, a high-frequency signal is output as in, and the high-frequency signal is supplied to the antenna through the previously closed relay contact 52a. You.

As can be seen from the sequence portion triggered by the rise of the press signal in FIG. 6, the time constant C ₁ R
_The transmission unit 51 can be changed after the transmission button is pressed.
Causing the timing t ₂ to which electric power is supplied, it is adjusted so the contacts of the relay 2 is slower than the timing t ₃ when to end the chattering operation, the left chattering operation plus high frequency signal 56 to the contacts of the relay 52 to Can be avoided, and therefore, it is possible to prevent the contacts of the relay 52 from deteriorating. Therefore, the delay circuit 55 effectively functions to prevent the deterioration of the relay contact.

However, when the transmission button of the radio is released, first, the transistor Tr ₄ is turned off, and as a result, the transistor Tr ₃ is turned off. Causes a chattering operation for a while and switches from the 52a side to the 52b side. Thereafter, the receiving circuit and the antenna stabilize in the connected state.

On the other hand, the capacitor C₁Is charged to
Resistance R₁Through the time constant C₁R₁Determined by
Transistor Tr_TwoTurn off,
As a result, the transistor Tr₁To turn off the
Time constant C after the tongue is released ₁R₁Time determined by
After elapse, power is not supplied to the transmission unit 51.
The high-frequency signal 56 is supplied with electric power to the transmitting unit 51.
After the data is no longer stored in the transmission unit 51
After the time when the residual power is
It becomes.

The above sequence will be described with reference to a time chart shown in FIG. When the button is released and the press signal falls, the relay drive current stops flowing, and the relay contact causes a chattering operation, and finally stabilizes. After the time determined by the time constant C ₁ R ₁ elapses from the time when the transmission button of the wireless device is released, the power supply of the transmission unit is turned off as shown in FIG. Change.

As described above, when the transmission button is released and the transmission is switched from transmission to reception, the timing t ₄ for starting the chattering operation before the relay 52 switches to the reception side, and the time constant C ₁ R The timing t until the residual power accumulated in the transmission unit 51 is further consumed after the time determined in ₁ and the output of the high-frequency signal is stopped.
₅ has a relationship of t ₄ <t ₅ , so that the chattering operation occurs while the high-frequency signal 56 is applied to the contact of the relay 52.

In the conventional circuit, the delay circuit 5
5 works in the direction of delaying t ₅ , and generally t ₄ <
a t _5. Therefore, the chattering operation occurs to deteriorate the contact of the relay 22. Therefore, in this case, the delay circuit 55 promotes the deterioration of the relay contact.

[0020]

As described above, in the configuration as shown in FIG. 5, there is no problem when the transmission button is pressed, but when the radio is switched from transmission to reception by releasing the button, the transmission unit 51 is not activated. While the high frequency is being output, the relay 52
The chattering operation described above causes problems such as deterioration of the contact point of the relay and sometimes shortening of the life of the element of the final output stage of the transmission unit 51.

However, the delay circuit 55 promotes the above problem, but is indispensable because it effectively functions to prevent the deterioration of the relay contact when the transmission button is pressed. Even if the chattering time of the relay 52 is short, the frequency of switching between transmission and reception in the wireless device is high, so that the accumulated deterioration of the relay contacts cannot be ignored.

Press signal input port and power switch 5
If the control output port 3 and the control output port of the relay drive unit 54 are connected to the CPU, sequence control without deteriorating the contacts of the relay 52 is possible, but it is difficult to reduce the size and weight and increase the cost is inevitable.

A technical object of the present invention is to avoid such a problem and to prevent chattering operation and deterioration of a relay contact while a high-frequency signal is applied without using a CPU or the like. .

[0024]

FIG. 1 is a block diagram for explaining the basic principle of a high-frequency relay switching circuit according to the present invention. The high-frequency relay switching circuit of the present invention also generates a high-frequency signal by delaying the high-frequency output control signal (8) indicating a transmission output instruction by a delay time corresponding to the time from the chattering of the relay (2) to the stabilization. A delay circuit (5) for outputting a power control signal (7) of the unit (1), and a high frequency generator (1) for receiving a power control signal (7) and controlling power supplied to the high frequency generator (1). A power switch (3),
The high-frequency output control signal (8) and the high-frequency signal (6)
A high-frequency output state signal (12) indicating the output state of the relay input signal, and when a transmission output is detected based on the high-frequency output control signal (8), a relay drive control signal (10) for driving the relay (2) And detecting the absence of high-frequency signal output based on the high-frequency output state signal (12),
Control means (9) for stopping the output of the relay drive control signal (10); and a relay for receiving the relay drive control signal (10) and opening and closing the high frequency signal (6) output from the high frequency generator (1). And (2) a relay drive section (4) for supplying a current to the coil.

In such a circuit, the present invention provides a high-frequency output detecting section 11 for detecting a high-frequency output of the high-frequency generating section 1 and outputting a high-frequency output state signal 12 to the control means 9 (for example, an OR circuit). Control means 9 is provided for outputting a relay drive control signal 10 to relay drive unit 4 when at least one of control signal 8 and high frequency output state signal 12 is input.

[0026]

FIG. 2 is a time chart for explaining the operation of the basic principle of the present invention shown in FIG.

As shown in FIG. 2, the rising edge of the high-frequency output control signal 8 triggers the control means 9 to control the relay driving section 4, and the relay driving section 4 starts driving the relay 2 as shown in FIG. The relay 2 performs a chattering operation for a while as shown in FIG.

On the other hand, after a lapse of the delay time from the trigger, the delay circuit 5 controls the power switch 3 of the high-frequency generator 1 as described above, and the power switch 3 supplies power to the high-frequency generator 1. As a result, as shown in FIG.
Outputs a high-frequency signal 6. Thus, the timing t ₂ from the trigger to the output of the high frequency signal 6 by the high frequency generator 1 can be delayed by adjusting the delay time of the delay circuit 5. Therefore, in the case of the present invention,
If the timing t ₂ that can be varied by the delay circuit 5 is adjusted to be later than the timing t _{3 at} which the contact point of the relay 2 ends the chattering operation, the high-frequency signal 6 is output after chattering has passed, as shown in FIG. And does not deteriorate the relay contact.

When power is supplied to the high-frequency generator 1 and the high-frequency signal 6 is output, the high-frequency output detector 11 inputs the high-frequency signal 6 to the control means 9. The relay control does not change.

On the other hand, the control means 9 stops the control of the relay driving section 4 with the falling of the high-frequency output control signal of FIG. 2 as a trigger, but the high-frequency generating section 1 outputs the high-frequency signal 6 during the period. , The high-frequency output detection unit 11
Keep controlling. As a result, even if the high-frequency output control signal falls as shown in FIG.
Is output, the relay drive unit 4 keeps driving the relay 2.

Therefore, the timing t _{4 at} which the relay 2 starts the chattering operation by the trigger and the timing t ₅ until the high-frequency generator 1 stops outputting the high-frequency signal.
In the conventional example, the relationship was generally t ₄ <t ₅ , whereas the above operation of the control means 9 changed to the relationship t ₄ > t _{5, and} the high-frequency signal 6 was applied to the contact of the relay 2. It is possible to prevent chattering operation from occurring and deterioration.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, how the high-frequency relay switching circuit according to the present invention is actually embodied will be described with reference to embodiments. FIG. 3 is a circuit diagram showing an embodiment of the present invention.

Reference numeral 31 denotes a transmitting unit for generating a high frequency, which is connected to an antenna via a relay 32. Relay 32
In the state where the contact is connected to the 32b side, the antenna and the receiving circuit of the wireless device are connected to be in a receiving state. In a state where the contact point of the relay 32 is connected to the side 32a, the transmission unit 31 is connected to the antenna and the transmission state is established.

The coil of the relay 32 has a transistor Tr
₃ is connected and transistor Tr ₄ is connected to transistor Tr ₃
By connecting via a bias resistor R ₄ to constitute a relay drive unit 34. Current flows to the base of the transistor Tr _4, the transistor Tr ₄ is that the turned on, the transistor Tr ₃ is turned on, resulting in a current flows through the coil of the relay 32.

On the other hand, the power switch 33 of the transmission unit 31 is configured by connecting the transistor Tr ₂ to the transistor Tr ₁ connected to the transmission unit 31 via the resistor R ₃ . Current flows to the base of the transistor Tr _2, by the transistor Tr ₂ is turned on, the transistor Tr
₁ is turned on, and as a result, power is supplied to the transmission unit 31.

Pressing the send button has a delay effect
The resistance R_TwoAnd capacitor C₁, And release button
The capacitor C₁To discharge the charge
Resistance R₁Constitutes the delay circuit 35. Submit
The resistance R from when the button is pressed _TwoAnd capacitor C₁Directly
The column circuit starts charging and the capacitor C₁No electricity
Is the transistor Tr_TwoEnough to pass the base current of
The transistor Tr_TwoTurns on. Obedience
Thus, power is supplied to the transmission unit 31.

When the transmission button is released, the capacitor C ₁ starts discharging through the resistor R ₁ , and when the potential of the capacitor C ₁ drops to a point where the base current of the transistor Tr ₂ cannot flow through the discharging, the transistor Tr ₂ Turns off. Therefore, power is not supplied to the transmission unit 31.

On the other hand, the OR circuit 39 is formed by connecting the resistors R ₅ and R ₆ in parallel to the base of the transistor Tr ₄ . A current flows through the at least one of the resistor R ₅ resistors R _6, transistor Tr ₄ is turned on, the result transistor Tr ₃ is turned on, a current flows through the coil of the relay 32.

Normally, a signal already used inside the transmission section 31 in APC (automatic transmission power control) or transmission power detection can be used as the high-frequency output state signal 12, so that the high-frequency output detection section 11 in FIG. Is unnecessary.
FIG. 4 shows the high-frequency output detector 11 when there is no corresponding signal.
FIG. 3 is a circuit diagram showing an example of the embodiment. High frequency output detector 11
It is to obtain a capacitor C ₂ and a diode D _1, and the detected voltage from the transmission power taken out by the directional coupler constituting a directional coupler for taking out rectifies the transmission power output from the transmitter 31 composed of a capacitor C _3.

In FIG. 4, a capacitor C ₂ operates as a high-pass filter for extracting a high-frequency component at a power detection point of the transmission unit 31. High-frequency component extracted by the capacitor C ₂ is half-wave rectified by the diode D _1, the capacitor C _3, the charge is charged by the rectified current, a voltage is generated.

[0041]

As described above, the contact point of the relay 2 has been deteriorated by the chattering operation during the output of the high-frequency signal in the transitional period at the time of the falling edge of the transmission, in which the transmission is stopped. It is possible to prevent the contact of the relay 2 from deteriorating due to the chattering operation at both the rising and falling of the high frequency output.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the basic principle of a high-frequency relay switching circuit according to the present invention.

FIG. 2 is a time chart showing the operation of the circuit of the present invention.

FIG. 3 is a circuit diagram showing an embodiment of the present invention.

FIG. 4 is a circuit diagram illustrating an embodiment of a high-frequency output detection unit.

FIG. 5 is a circuit diagram showing a conventional high-frequency relay switching circuit.

FIG. 6 is a time chart showing the operation of a conventional high-frequency relay switching circuit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 high-frequency generator (transmitter) 2 relay 2 a relay contact 2 b relay contact 3 high-frequency generator power switch 4 relay driver 5 delay circuit 6 high-frequency signal 7 high-frequency generator power control signal 8 high-frequency output control signal (press signal) 9 control Means 10 Relay drive control signal 11 High frequency output detection unit 12 High frequency output state signal

Claims (1)

(57) [Claims] 1. An apparatus having a relay (2) for opening and closing a high-frequency signal (6) transmitted and output by a high-frequency generator (1), wherein the relay operates in response to a high-frequency output control signal (8) indicating a transmission output instruction. A delay circuit (5) that outputs a power control signal (7) of the high frequency generator (1) with a delay corresponding to the time from (2) chattering to stabilization.
A power switch (3) of a high-frequency generator (1) for inputting a power control signal (7) and controlling power supplied to the high-frequency generator (1); the high-frequency output control signal (8) and the high-frequency signal (6)
A high-frequency output state signal (12) indicating the output state of the relay input signal, and when a transmission output is detected based on the high-frequency output control signal (8), a relay drive control signal (10) for driving the relay (2) And detecting the absence of high-frequency signal output based on the high-frequency output state signal (12),
Control means (9) for stopping the output of the relay drive control signal (10); and a relay for receiving the relay drive control signal (10) and opening and closing the high frequency signal (6) output from the high frequency generator (1). (2) A high-frequency relay opening / closing circuit, comprising: a relay driving section (4) for supplying a current to the coil.