High frequency switch circuit comprising a transistor on the high frequency path

• US 8,159,283 B2
• Filed: 07/26/2006
• Issued: 04/17/2012
• Est. Priority Date: 08/09/2005
• Status: Active Grant

• Current Assignee: Hitachi Metals (Thailand) Ltd.
• Original Assignee: Hitachi Metals (Thailand) Ltd.
• Inventors: Sugiyama, Yuta
• Primary Examiner(s): Wells, Kenneth B.
• Application Number:
  US11/997,258
• Publication Number:
  US 20100090747A1
• Time in Patent Office: 2,092 Days
• Field of Search: 327/430, 327/434, 333101-103
• US Class Current: 327/430
• CPC Class Codes: H03K 17/693 Switching arrangements with several input- or output-terminals, e.g. multiplexers, distributors logic circuits H03K19/00; code converters H03M5/00, H03M7/00
• CPC Class Codes: H03K 2017/0806 against excessive temperature
• CPC Class Codes: H03K 2017/6875 using self-conductive, depletion FETs

Abstract

A high frequency switch circuit according to the present invention includes a control-voltage-generating circuit. The control-voltage-generating circuit includes a depletion type field-effect transistor, an external-control-signal-input terminal, an internal-control-voltage-output terminal, and a power-receiving terminal of the control-voltage-generating circuit. The field-effect transistor has a grounded gate, a source connected to the external-control-signal-input terminal, and a drain connected to the power-receiving terminal. The internal-control-voltage-output terminal is connected to an electrical connection path between the drain of the field-effect transistor and the power-receiving terminal.

Claims

1. A high frequency switch circuit having a switch circuit adapted to switch a connection state and a disconnection state of a high frequency signal path, and a control-voltage-generating circuit adapted to generate an internal control voltage for controlling the switch circuit on the basis of an external control signal,

wherein the control-voltage-generating circuit includes a high-frequency-circuit-connecting terminal, an external-control-signal-input terminal, a depletion type field-effect transistor, first and second resistors, an internal-control-voltage-output terminal, a capacitor, and a diode,

wherein the field-effect transistor has a grounded gate, a source connected to the external-control-signal-input terminal, and a drain connected to the internal-control-voltage-output terminal via a first node,

wherein the first resistor has one terminal connected to the first node and the other terminal connected to a second node,

wherein the second resistor has one terminal connected to the second node and the other terminal connected to the external-control-signal-input terminal,

wherein the capacitor has one terminal connected to the high frequency signal path via the high-frequency-circuit-connecting terminal and the other terminal connected to the second node,

wherein the diode has a cathode connected to the second node and an anode connected to the external-control-signal-input terminal, and

wherein the internal-control-voltage-output terminal is connected to the switch circuit.

2. A single-pole-multiple-throw-type high frequency switch circuit having at least a first high frequency switch circuit and a second high frequency switch circuit,

wherein the first and second high frequency switch circuits are the high frequency switch circuit according to claim 1, and

wherein one end of the high frequency signal path in both the first and second high frequency switch circuits is connected to a common high frequency port, and one terminal of the capacitor provided in the control-voltage-generating circuit is connected to the common high frequency port via the high-frequency-circuit-connecting terminal.

3. The high frequency switch circuit according to claim 1, wherein all active elements used in the high frequency switch circuit are depletion type field-effect transistors having substantially the same pinch-off voltage as the field-effect-transistor.

4. The high frequency switch circuit according to claim 1, wherein the first resistor is an active load.

5. The high frequency switch circuit according to claim 1, wherein the internal-control-voltage-output terminal is connected to the switch circuit via a low pass filter.

6. The high frequency switch circuit according to claim 1, wherein the gate of the field-effect transistor is grounded via a third resistor.

7. A high frequency switch circuit having a switch circuit adapted to switch a connection state and a disconnection state of a high frequency signal path, and a control-voltage-generating circuit adapted to generate an internal control voltage for controlling the switch circuit on the basis of an external control signal,

wherein the control-voltage-generating circuit comprises a high-frequency-circuit-connecting terminal, an external-control-signal-input terminal, a depletion type field-effect transistor, a first resistor, an internal-control-voltage-output terminal, a capacitor, and a diode,

wherein the field-effect transistor has a grounded gate, a source connected to the external-control-signal-input terminal, and a drain connected to a second node,

wherein the diode has a cathode connected to the second node and an anode connected to a first node,

wherein the first resistor has one terminal connected to an electrical connection path between the first node and the internal-control-voltage-output terminal, and the other terminal connected to the external-control-signal-input terminal,

wherein the capacitor has one terminal connected to the high frequency signal path via the high-frequency-circuit-connecting terminal and the other terminal connected to the first node, and

wherein the internal-control-voltage-output terminal is connected to the switch circuit.

8. The high frequency switch circuit according to claim 7, wherein the gate of the field-effect transistor is grounded via a second resistor.

9. A single-pole-multiple-throw-type high frequency switch circuit having at least a first high frequency switch circuit and a second high frequency switch circuit,

wherein the first and second high frequency switch circuits are the high frequency switch circuit according to claim 7, and

wherein one end of the high frequency signal path in both the first and second high frequency switch circuits is connected to a common high frequency port, and one terminal of the capacitor provided in the control-voltage-generating circuit is connected to the common high frequency port via the high-frequency-circuit-connecting terminal.

10. The high frequency switch circuit according to claim 7, wherein all active elements used in the high frequency switch circuit are depletion type field-effect transistors having substantially the same pinch-off voltage as the field-effect-transistor.

11. The high frequency switch circuit according to claim 7, wherein the first resistor is an active load.

12. The high frequency switch circuit according to claim 7, wherein the internal-control-voltage-output terminal is connected to the switch circuit via a low pass filter.