ELECTRONIC CIRCUIT AND ELECTRONIC DEVICE

• US 20110163824A1
• Filed: 12/22/2010
• Published: 07/07/2011
• Est. Priority Date: 01/05/2010
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: KAWANO, Yoichi
• Granted Patent: US 8,441,334 B2
• Time in Patent Office: Days
• US Class Current: 333/17.3
• CPC Class Codes: H01F 21/02 continuously variable, e.g. variometers
• CPC Class Codes: H01F 21/12 discontinuously variable, e.g. tapped
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• CPC Class Codes: H03F 2200/378 A variable capacitor being added in the output circuit, e.g. collector, drain, of an amplifier stage
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/391 the output circuit of an amplifying stage comprising an LC-network
• CPC Class Codes: H03F 2200/411 the output amplifying stage of an amplifier comprising two power stages
• CPC Class Codes: H03F 3/193 with field-effect devices H03F3/195 takes precedence
• CPC Class Codes: H03H 2210/012 Centre frequency; Cut-off frequency
• CPC Class Codes: H03H 2210/026 Inductor
• CPC Class Codes: H03H 2210/036 Stepwise
• CPC Class Codes: H03H 7/0153 Electrical filters; Controlling thereof

Abstract

An electronic circuit includes a first inductor, a second inductor that is magnetically coupled with the first inductor, induced current flowing through the second inductor by a magnetic field generated by the first inductor, and a current changing part that is connected to the second inductor and is configured to change the induced current that flows through the second inductor.

Claims

1. An electronic circuit comprising:

a first inductor;

a second inductor that is magnetically coupled with the first inductor, induced current flowing through the second inductor by a magnetic field generated by the first inductor; and

a current changing part that is connected to the second inductor and is configured to change the induced current that flows through the second inductor.

2. The electronic circuit as claimed in claim 1, wherein the current changing part includes a switching part that switches the induced current flowing through the second inductor to zero or a predetermined value other than zero.

3. The electronic circuit as claimed in claim 2, wherein the switching part includes a switch that is connected between ends of the second inductor and opens or closes the second inductor.

4. The electronic circuit as claimed in claim 1, further comprising an adjusting part that continuously changes the induced current flowing through the second inductor within a given range.

5. The electronic circuit as claimed in claim 4, wherein the adjusting part includes an additional impedance that is connected to an end of the second inductor and continuously changes the impedance of the second inductor.

6. The electronic circuit as claimed in claim 5, wherein the additional impedance includes a variable capacitance diode.

7. The electronic circuit as claimed in claim 1, wherein the first inductor and the second inductor include wiring patterns formed on a substrate.

8. The electronic circuit as claimed in claim 7, wherein the second inductor has multiple inductors that are formed inside the first inductor and have different inner diameters.

9. The electronic circuit as claimed in claim 7, wherein the first inductor and the second inductor are formed on an identical layer on the substrate.

10. The electronic circuit as claimed in claim 7, wherein the first inductor and the second inductor are formed on different layers that are stacked so as to include an interposed insulating layer between the different layers.

11. The electronic circuit as claimed in claim 10, wherein the second inductor include portions that overlap each other in a direction in which the different layers are stacked.

12. The electronic circuit as claimed in claim 1, further comprising an amplifier part that amplifiers an input signal, a matching circuit that includes the first inductor and matches an output impedance of the amplifier part, and a control part that controls the current changing part on the basis of the input signal and changes an impedance of the matching circuit.

13. The electronic circuit as claimed in claim 12, wherein the control circuit changes the impedance of the matching circuit so that a power added efficiency increases as the input signal decreases and a saturated power of the electronic circuit increases as the input signal increases.

14. The electronic circuit as claimed in claim 12, wherein the current changing part includes a variable capacitance diode connected to an end of the second inductor, and the control circuit changes the impedance of the matching circuit so that the saturated power of the electronic circuit increases as the input signal increases.

15. The electronic circuit as claimed in claim 1, wherein the first inductor includes a low-pass filter circuit.

16. The electronic circuit as claimed in claim 15, wherein the first inductor is connected in series between an input terminal of the low pass filter circuit and an output terminal thereof.

17. The electronic circuit as claimed in claim 1, further comprising a high-pass filter circuit including the first inductor.

18. An electronic device comprising an electronic circuit configured to include:

a first inductor;

a second inductor that is magnetically coupled with the first inductor, induced current flowing through the second inductor by a magnetic field generated by the first inductor; and

a current changing part that is connected to the second inductor and is configured to change the induced current that flows through the second inductor.