Semiconductor integrated switching circuit

• US 6,407,614 B1
• Filed: 03/29/2001
• Issued: 06/18/2002
• Est. Priority Date: 12/07/2000
• Status: Expired due to Fees

• Current Assignee: New Japan Radio Company Limited (Nisshinbo Holdings Incorporated)
• Original Assignee: New Japan Radio Company Limited (Nisshinbo Holdings Incorporated)
• Inventors: Takahashi, Masaru
• Primary Examiner(s): ZWEIZIG, JEFFERY SHAWN
• Application Number:
  US09/819,761
• Publication Number:
  US 20020075059A1
• Time in Patent Office: 446 Days
• Field of Search: 327/407, 327/408, 327/415, 327/416
• US Class Current: 327/415
• CPC Class Codes: H03K 17/162 without feedback from the output circuit to the control circuit
• 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: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes

Abstract

The semiconductor integrated switching circuit S1 employed in a dual-band mobile phone comprises the first through fourth field effect transistor 1, 2, 3, 4 by which electrical connection between either of the first through fourth input/output terminal 22 through 25 and the common input-output terminal 21 are controlled, the fifth field effect transistor 5 which becomes conducting with the second field effect transistor 2, and the series resonance circuit 51 having a resonance frequency equals to a frequency of higher harmonic of the signal passing through the second field effect transistor 2. The fifth field effect transistor 5 and the series resonance circuit 51 are connected in series and attached between the common input-output terminal 21 and the ground so as to divert the higher harmonic of the signal without giving passing loss to the signal.

Claims

1. A semiconductor integrated switching circuit for connecting a common input-output terminal selectively to any one of input/output terminals comprising,

switching elements for selectively connecting terminals, each of which interposed between the common input-output terminal and respective one of the input/output terminals, and controlled by a control voltage applied externally;

a ground terminal for grounding;

a series resonance circuit having a resonance frequency set to be a higher harmonic of the fundamental frequency that passes trough one of the switching elements;

and a switching element for the series resonance circuit,

wherein the series resonance circuit and the switching element for the series resonance circuit are connected in series and interposed between the common input-output terminal and the ground terminal,

and the control voltage applied to said one of the switching elements is commonly applied to the switching element for the series resonance circuit.

2. The semiconductor integrated switching circuit of claim 1, wherein plurality of series resonance circuits each of which is connected to respective switching element for series resonance circuit in series and interposed between the common input-output terminal and the ground terminal.

3. The semiconductor integrated switching circuit of claim 1, wherein series resonance circuits having different resonance frequencies are connected in parallel each other and interposed between the switching element for series resonance circuit and the ground terminal.

4. The semiconductor integrated switching circuit of claim 1, wherein each of said switching elements for selectively connecting terminals is field effect transistor, either a drain or source thereof is connected to said common input-output terminal and the other is connected to respective one of said input/output terminals, and said control voltage is applied to its gate via a gate resistor,

and said switching element for series resonance circuit is a field effect transistor, either a drain or source thereof is connected to said common input-output terminal and the other is connected to said ground terminal, and said control voltage is applied to its gate via a gate resistor.

5. The semiconductor integrated switching circuit of claim 1,

wherein the series resonance circuit comprises a capacitor and an inductor which are connected in series,

the capacitor is attached between the switching element for series resonance circuit and the ground terminal, and the inductor is attached externally between the ground terminal and the ground so that the ground terminal is grounded through the inductor.