JPH0922632A - High-frequency semiconductor switch module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switch module of low power consumption and high isolation by connecting a FET which has a normally off characteristic between a single electrode of an SIT connected to a transfer circuit and having a normally off characteristic and ground. SOLUTION: An SIT is connected in series between terminals 1, 2, and a FET is connected between the terminal 1 and ground. The SIT and the FET must be a normally on element and a normally off element, respectively. This circuit constitution eliminates the need to apply signals to both control terminals 3, 4, in a waiting state, for example, with almost no power consumed. In this case the terminal 1 is connected to a receiver RX and the terminal 2 to an antenna ANT.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency semiconductor switch module for mobile communication equipment using SIT which is characterized by low power consumption.

[0002]

2. Description of the Related Art In recent years, the use of high frequency semiconductor switches has been expanding, and in particular, low power consumption switches are required to prolong battery life.

In addition, a high isolation function is also necessary so that telephone calls do not leak. This high isolation function can be achieved by reducing the leak current of the device.

FIG. 3 shows an SPST using a conventional FET.
It is an example of a (Single Pole Single-Throw) switch.
This circuit uses two elements of the same type. For example, in the case of a normally-off element, FET1 is OFF and FE in the conductive state between the terminal (1) 31 and the terminal (2) 32.
T2 must be ON. In the case of the reverse type element, FET1 is ON and FET2 is OFF. In any case, since the control voltage must be applied to one of the FETs, power consumption cannot be avoided.

[0005]

In the conventional changeover switch, for example, a plurality of normally-off (or normally-on) type elements are used in the same circuit, so that the control voltage is supplied in both the switch-on state and the off-state. Must be applied continuously. Therefore, the semiconductor element consumes electric power, which causes the battery life to be shortened. The present invention
In order to improve the above drawbacks, it is an object to provide a high frequency semiconductor switch module with low power consumption and high isolation.

[0006]

A high-frequency semiconductor switch used in a mobile communication device, which has high withstand voltage characteristics, low power consumption (low loss) and isoelectric characteristics in place of a conventional PIN diode switch or GaAs-FET switch. Use SIT with excellent ration characteristics. That is, a SIT having a normally-on characteristic is connected in series with the transmission line, and the SI
FE having a normal-off characteristic between one electrode of T and the ground
T (eg, heterojunction FET) is connected. That is,
The normal on element and the normal off element are used in the same circuit.

Conventional GaAs BJT (or FET), etc.
The changeover switch that is combined only with the transistor of the normal on (or normal off) function must be energized even in the call waiting state, and the transistor always consumes energy. On the other hand, if the changeover switch is configured by combining the SIT having the normal-on characteristic and the FET having the normal-off characteristic, the power of the switch circuit may be turned off in the call waiting state, and there is a long call waiting time. However, there is no power consumption and the battery lasts a long time.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples.

FIG. 1 shows one embodiment of the present invention. Connect SIT in series between terminal (1) 1-terminal (2) 2,
An FET is connected between the terminal (1) and ground. FE of FIG.
The T2 is replaced by SIT. Further, it is an essential condition that the SIT is a normal on element and the FET is a normal off element.

With the circuit configuration as described above, for example,
In a call waiting state, SIT is a normally-on element, FET
Is a normally-off element, so control (1) 1, (2)
In both cases, it is possible to add no signal and consume almost no power. In this case, the terminal (1) 1 is connected to the receiver (Rx) and the terminal (2) 2 is connected to the antenna.

In general, the mobile communication device consumes most of the power consumption during transmission and the power consumption during the call waiting time. The present invention makes it possible to reduce power consumption during a call waiting time to a minimum.

At the time of transmission, as shown in FIG. 2, it is necessary that SIT be 0FF and FET be ON. In this case, a control signal is required for both elements.

[0013]

The SIT having a normal-on characteristic is connected in series to the transmission circuit, and the FET having a normal-off characteristic is connected between the one side electrode of the SIT and the ground, thereby reducing the power consumption and the high isolation high frequency. A semiconductor switch module was obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit configuration of an SPST switch (reception side) using an SIT according to the present invention.

FIG. 2 is a diagram showing a circuit configuration of an SPST switch (transmission side) using the SIT according to the present invention.

FIG. 3 is a diagram showing a circuit configuration of a SPST switch using a conventional GaAs FET.

[Explanation of symbols]

 1 terminal (1) (Rx) 2 terminal (2) (ANT) 3,23,33 control (1) 4,24,34 control (2) 21 terminal (1) (Tx) 22 terminal (2) (ANT) 31 terminals (1) 32 terminals (2)

Claims (2)

[Claims] 1. A high frequency wave characterized in that at least one SIT having a normal-on characteristic is connected to a transmission line, and at least one FET having a normal-off characteristic is connected between one electrode of the SIT and ground. Semiconductor switch module. 2. A high-frequency semiconductor switch module comprising a SIT having a normal-on characteristic connected in series with a transmission line, and a FET having a normal-off characteristic connected between one electrode of the SIT and ground.