KR20010019107A - Radio frequency switch - Google Patents

Abstract

PURPOSE: A radio frequency switch is provided to improve a radio frequency separation between an input unit and an output unit of a switch by constituting a twin of semiconductor diode for a diode. CONSTITUTION: A semiconductor diode(30) is connected between an input unit(26) and an output unit(28) of a switch(20). A digital logic unit(22) consists of the first output unit(Q) for generating the first DC(direct current) voltage(+V), the second output unit(bar Q) for generating a voltage(-V) reverse to the first DC voltage(+V), and a starting input unit. The first output unit(Q) is connected with a cathode of the semiconductor diode(30), and the second output unit(bar Q) is connected with an anode of the semiconductor diode(30). The first voltage(+V) and the reverse voltage(-V) biases the semiconductor diode(30) in reverse direction, when the digital logic unit(22) is in the first state and a control signal received by a starting input unit of the digital logic unit changes. The digital logic unit(22) changes into the second state that the first output unit(Q) generates the reverse voltage(-V) and the second output unit(bar Q) generates the first voltage(+V), biases the semiconductor diode(30) in ordinary direction and connects the input unit(26) of the switch(20) with the output unit(28) of the switch(20).

Description

Radio Frequency Switch {RADIO FREQUENCY SWITCH}

The present invention relates to a radio frequency switch operable to communicate radio frequency signals from an input of a switch to an output of the switch in accordance with a switch signal applied to the control input of the switch.

The switch for radiofrequency signals must be able to isolate the radio frequency signal applied to the input of the switch when the switch is in the 'off' state, while providing an effective conduit of the radio frequency signal when the switch is in the 'off' state. The radio frequency switch should eliminate the problem of the first technique that can effectively isolate the input of the switch from the output when the switch is in the 'off' state. The second technical problem with radio frequency switches is that it is not easy to switch from an 'on' state to an 'off' state in a time fast enough for a predetermined amount of radio frequency energy to be delivered to the output.

A schematic diagram illustrating an embodiment of a conventional radio frequency switch is shown in FIG. 1. The radiofrequency switch 1 in FIG. 1 has a control input formed between the input 2, the output 4, and further terminals 6, 8. The radio frequency switch 1 comprises a semiconductor diode 10 connected between the output section 4 and the input section 2 via decoupling capacitors 12, 14. The control input terminals 6, 8 are connected opposite the cathode and the anode of the diode 10 via respective first and second radio frequency chokes 16, 18. In the operation of the conventional radiofrequency switch shown in FIG. 1, while the diode 10 is in an 'off' state, a signal applied to the input terminal 2 does not reach the output terminal 4. Thus, the 'off' state is obtained by applying a dc voltage between the control input terminals 6, 8 so that the diode 10 is reverse biased. Correspondingly, when the diode 10 is inverted so that it is obtained by applying a suitable DC voltage between the control input terminals 6 and 8 so that the diode 10 is forward biased, the radio frequency signal applied to the input terminal 2 is output. It is passed to terminal 4.

A disadvantage with the conventional form of such a radiofrequency switch is via the terminals 6, 8 to the output 4 of the switch 1, which bypasses the diode 10 when a high frequency signal is applied to the input of the switch. In other words, through the radio frequency choke (16, 18), the radio frequency choke (16, 18) does not effectively block the radio frequency signal from being transmitted from the input terminal (2). Thus, for signals in the range between 1 and 10 GHz, this arrangement is not satisfactory. Alternatively, increased radio frequency separation can be obtained by increasing the inductance of the radio frequency choke 16,18. However, this is an effect of increasing the time taken by the switch 1 to change from the 'off' state to the 'on' state, and has a disadvantage in that the time for the diode 10 to conduct is increased. Thus, this conventional radio frequency switch 1 cannot be used to switch a radio frequency signal of a considerably short duration between the input portion 2 and the output portion 4.

The above-mentioned disadvantages represent the technical problem addressed by the present invention in the separation of high frequency signals between the input and output of the radio frequency switch and in the arrangement of rapidly changing switches from 'off' to 'on' states.

1 is a schematic diagram illustrating an embodiment of a radio frequency switch of the prior art;

2 is a schematic block diagram of a first embodiment of a radio frequency switch;

3 is a schematic block diagram of a second embodiment of a radio frequency switch;

According to the present invention, there is provided a radio frequency switch operative to communicate radio frequency signals from an input of a switch to an output of the switch in accordance with a control signal, wherein the radio frequency switch is a semiconductor diode connecting between the input and the output of the switch, Digital logic means having a first output for generating a first DC voltage (+ V) and a second output for generating a reverse voltage (-V) of the first DC voltage, a start input connected to a control input of a radio frequency switch Wherein the first output of the digital logic means is connected to a cathode of a diode, the second output of the digital logic means is connected to an anode of a diode, and the digital logic means is in a first state When a change occurs in the control signal supplied to the start input of the digital logic means, the first voltage (+ V) and the reverse voltage of the first voltage (- V) has the effect of reverse biasing the diode, and by digitally biasing the semiconductor diode and connecting the input of the switch to the output of the switch, the digital logic means is inverse of the first voltage generated by the first output. Generates a voltage (-V) and changes to a second state where the second output portion generates a first voltage (+ V).

By using digital logic means that forward bias the diode when the switch is in the 'on' state and reverse bias the diode when the switch is in the 'off' state, fast switching times are achieved as a result of the relatively fast operation of the digital logic means. On the other hand, radio frequency separation is possible. The digital logic means comprises a digital logic gate that can be manufactured according to an emitter connected to the logic. The digital logic means can be flip-flop. The flip-flop may be a D-type flip-flop.

The semiconductor diode may comprise a pair of first and second semiconductor diodes each connected in series with the first pair and in parallel with the second pair, wherein the input of the radio frequency switch comprises a pair of first It is formed in the connection part between one diode, and the output part of a radio frequency switch is formed in the connection part between a pair of 2nd diode.

The pair of first and second semiconductor diodes can be formed separately from the semiconductor module to substantially improve radio frequency separation between the output and the input of the switch.

Embodiments of the present invention will be described by the following appended drawings.

2 is a schematic block diagram of a first embodiment of a radio frequency switch.

3 is a schematic block diagram of a second embodiment of a radio frequency switch.

In Fig. 2, the output part Q generates a DC voltage of + V when the control input part D 24 is at a low DC voltage in an active transition of the clock signal CLK applied to the clock input part 38. And an output for generating a DC voltage of -V An RF switch 20 is shown including a D-type flip-flop 22 with

The diode 30 is connected between the input portion 26 of the switch 20 and the output portion 28 of the switch 20, and the input portion 26 and the output portion 28 via the capacitors 32, 34. AC connected to. Q and Q from the flip-flop 22 connected to the cathode and the anode of the diode 30. The circuit is completed by biasing the resistor R for arranging the output of the circuit. The bias of the resistor R causes the diode 30 to remain in the reverse bias mode, while the flip-flop 22 causes the output Q to produce a positive DC voltage (+ V) and ) Is placed in a first mode that produces a negative DC voltage (-V). A feature of the switch 20 is that the flip-flop 22 includes an emitter that connects a logic gate providing a flip-flop with a switching time of about 50 psec. However, it can also be used in other semiconductor active devices and logic designs. When the switching pulse 36 is applied and received at the input 24 of the flip-flop 22, the output Q is the negative voltage (-V), while the output ( The flip-flop switches at or above the active voltage of the clock signal CLK applied to the clock input 38 so that) is a positive voltage (+ V). This has the effect of forward biasing the diode 30, causing the diode 30 to be conductive, that is to say the effect of the input 26 being connected to the output 28 and thus the output at the input 26. While a signal is transmitted to 28, the control input 24 is made high. With this switch arrangement, a switching time on the order of 50 psec is possible, and as a result, the radio frequency switch 20 has a time on the order of 500 ps and a distortion time by the switching time by only about 10% of this time. It can work to deliver.

A more preferred embodiment of the present invention is shown in FIG. 3, and the parts shown in FIG. 2 use the same numeral symbols. Except for replacing diode 30 with two pairs of diodes 40, 42, 44, 46, the radiofrequency switch shown in FIG. 3 is identical to the radiofrequency switch shown in FIG. Furthermore, the input and output of the radio frequency switch are connected to two pairs of diodes. Diode 30 is replaced by two pairs of series-connected diodes 40, 42, 44 and 46, each pair connected in parallel with the other pair and having Q and Q of flip-flop 22 It is connected between the outputs of. The input section 26 of the radio frequency switch 20 is connected between the junctions between the pairs 40 and 42 of the first diodes connected in series via the capacitor 32 and the output section 28 of the radio frequency switch. Is connected to the junction between the pair 44, 46 of second diodes connected in series via the capacitor 34. A pair 40, 42 of the first diode is formed in the first semiconductor package 50 and a pair 44, 46 of the second diode is formed in the second semiconductor package 48.

The effect of replacing the first and second semiconductor diode pairs instead of the diode 30 is that the radio frequency separation between the output 28 and the input 26 of the switch is improved. On the other hand, the operation of the radio frequency switch shown in FIG. 3 substantially coincides with that described in FIG. 2 and is therefore not mentioned here. Further advances in isolation are made by disposing first and second semiconductor diode pairs made of perforated semiconductor packages 48 and 50.

As will be appreciated by those skilled in the art, various modifications of the above-mentioned embodiments can be made and are also within the scope of the present invention.

Claims (6)

A radio frequency switch operable to communicate radio frequency signals from an input of a switch to an output of a switch in accordance with a control signal applied to a control input of the switch, A semiconductor diode connected between the output of the switch and the input of the switch; And Digital logic having a first output for generating a first DC voltage (+ V), a second output for generating a reverse voltage (-V) of the first DC voltage, and a start input coupled to the control input of the radio frequency switch Way; Including; The first output of the digital logic means is connected to the cathode of the diode, the second output of the digital logic means is connected to the anode of the diode, and the first voltage (+ V) and the reverse voltage of the first voltage (- V) has the effect of biasing the diode in the reverse direction when the digital logic means is in a first state and as a result there is a change in the control signal supplied to the start input of the digital logic means, the digital logic means Is switched to a second state in which the first output portion generates a reverse voltage (-V) of the first voltage and the second output portion generates a first voltage (+ V), thereby biasing the semiconductor diode in the forward direction and switching A radio frequency switch comprising connecting the input of the switch to an output of the switch. The semiconductor device of claim 1, wherein the semiconductor device comprises a first and a second semiconductor diode pair connected in series with each other, the first semiconductor diode pair is connected in parallel with the second semiconductor diode pair, and an input portion of the radio frequency switch And an output of the radio frequency switch is connected to the junction between the second diode pair. 3. A radio according to claim 1 or 2, wherein the first and second semiconductor diode pairs are fabricated in a perforated semiconductor package to substantially improve radio frequency separation between the output of the switch and the input of the switch. Frequency switch. 4. A radio frequency switch according to any one of the preceding claims, wherein said digital logic means comprises a digital logic gate fabricated according to an emitter coupled to the logic. 5. A radio frequency switch according to any one of the preceding claims, wherein said digital logic means is a flip-flop, which can be a D-type flip-flop. The above-described radio frequency switch is a radio frequency switch, characterized in that described with reference to the accompanying drawings.