Switch circuit

• US 20090184747A1
• Filed: 12/19/2008
• Published: 07/23/2009
• Est. Priority Date: 01/22/2008
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Honda, Yuri
• Granted Patent: US 7,893,749 B2
• Time in Patent Office: Days
• 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

Abstract

There has been a problem that the distortion characteristic of a switch circuit for a high frequency is deteriorated. A switch circuit in accordance with one aspect of the present invention includes a transistor connected in series between input and output terminals, a control terminal that receives a signal to control the conductive state of the transistor, a first resistor connected between the control electrode of the transistor and the control terminal, and a series circuit of a diode and a second resistor, the series circuit being connected in parallel with the first resistor between the control terminal and the control electrode of the transistor.

Claims

1. A switch circuit comprising:

a transistor connected in series between input and output terminals;

a control terminal that receives a signal to control the conductive state of the transistor;

a first resistor connected between the control electrode of the transistor and the control terminal; and

a series circuit of a diode and a second resistor, the series circuit being connected in parallel with the first resistor between the control terminal and the control electrode of the transistor.

2. The switch circuit according to claim 1, wherein the diode comprises a plurality of serially connected diodes.

3. The switch circuit according to claim 1, wherein the anode of the diode is connected on the control terminal side and the cathode of the diode is connected on the control electrode side.

4. The switch circuit according to claim 2, wherein the anode of the diode is connected on the control terminal side and the cathode of the diode is connected on the control electrode side.

5. The switch circuit according to claim 1, wherein the anode of the diode is connected on the control electrode side and the cathode of the diode is connected on the control terminal side.

6. The switch circuit according to claim 2, wherein the anode of the diode is connected on the control electrode side and the cathode of the diode is connected on the control terminal side.

7. The switch circuit according to claim 1, wherein:

a plurality of the series circuits are connected in parallel;

at least one of the series circuits comprises a diode, the anode of the diode being connected on the control terminal side and the cathode of the diode being connected on the control electrode side; and

at least another one of the series circuits comprises a diode, the anode of the diode being connected on the control electrode side and the cathode of the diode being connected on the control terminal side.

8. The switch circuit according to claim 2, wherein:

a plurality of the series circuits are connected in parallel;

at least one of the series circuits comprises a diode, the anode of the diode being connected on the control terminal side and the cathode of the diode being connected on the control electrode side; and

at least another one of the series circuits comprises a diode, the anode of the diode being connected on the control electrode side and the cathode of the diode being connected on the control terminal side.

9. The switch circuit according to claim 1, wherein a plurality of the transistors are connected in series between the input and output terminals.

10. The switch circuit according to claim 1, further comprising a third resistor, one end of the third resistor being connected to the control electrode of the transistor and the other end of the third resistor being connected to the first resistor and the series circuit.

11. The switch circuit according to claim 10, wherein the other ends of a plurality of the third resistors connected to the control electrodes of a plurality of the transistors are connected in common, and the first resistor and the series circuit are provided in common for the plurality of the transistors.

12. The switch circuit according to Claim, 1, further comprising a bias supply resistor that connects the source and the drain of the transistor.

13. The switch circuit according to claim 1, wherein the second resistor is connected between the diode and the control electrode of the transistor.