Rectifier circuit, semiconductor device using the rectifier circuit, and driving method thereof

• US 20080083969A1
• Filed: 10/03/2007
• Published: 04/10/2008
• Est. Priority Date: 10/06/2006
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Osada, Takeshi
• Granted Patent: US 8,351,226 B2
• Time in Patent Office: Days
• US Class Current: 257/595
• CPC Class Codes: G06K 19/0715 the arrangement including means to regulate power transfer to the integrated circuit
• CPC Class Codes: H02M 7/06 using discharge tubes without control electrode or semiconductor devices without control electrode
• CPC Class Codes: H02M 7/4818 with means for adaptation of resonance frequency, e.g. by modification of capacitance or inductance of resonance circuits
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

An object of the present invention is to provide a rectifier circuit which can suppress loss of power due to parasitic capacitance or parasitic inductance of a semiconductor element. The rectifier circuit matches or mismatches impedance between a circuit of a previous stage and the rectifier circuit in accordance with the amplitude of an input AC voltage. When an AC voltage to be input has a smaller amplitude than a predetermined voltage, impedance is matched and the AC voltage is applied as is to the rectifier circuit. Conversely, when an AC voltage to be input has a larger amplitude than a predetermined voltage, impedance is mismatched, and the amplitude of the AC voltage is decreased by reflection and then the AC voltage is applied to the rectifier circuit.

Claims

1. A rectifier circuit comprising:

a variable capacitor and a plurality of diodes for rectifying an inputted AC voltage, wherein a capacitance value of the variable capacitor is changed in accordance with the amplitude of the AC voltage.

2. A rectifier circuit according to claim 1, further comprising:

wherein the rectifier circuit comprises a first diode, a second diode, a first input terminal, a second input terminal, and an output terminal,

wherein the plurality of diodes comprises a first diode and a second diode,

wherein the variable capacitor and the first diode are sequentially connected in series between the first input terminal and the output terminal; and

wherein the second diode and the first diode are sequentially connected in series between the second input terminal and the output terminal so that forward directions of the diodes are the same.

3. A rectifier circuit according to claim 2, wherein the variable capacitor is a p-channel MOS varactor.

4. The rectifier circuit according to claim 2, further comprising:

a capacitor connected in parallel with the first diode and the second diode.

5. A rectifier circuit according to claim 1, further comprising:

wherein the rectifier circuit comprises a capacitor, a first diode, a second diode, a first input terminal, a second input terminal, and an output terminal,

wherein the plurality of diodes comprises a first diode and a second diode,

wherein the capacitor and the first diode are sequentially connected in series between the first input terminal and the output terminal;

wherein the second diode and the first diode are sequentially connected in series between the second input terminal and the output terminal so that forward directions of the diodes are the same; and

wherein the variable capacitor and the second diode are connected in parallel between the second input terminal and the first diode.

6. A rectifier circuit according to claim 5, wherein the variable capacitor is an n-channel MOS varactor.

7. The rectifier circuit according to claim 5, further comprising:

a resistor connected between the capacitor and the first diode.

8. A rectifier circuit according to claim 1, further comprising:

wherein the rectifier circuit comprises a first diode, a second diode, a third diode, an input terminal, and an output terminal,

wherein the plurality of diodes comprises a first diode, a second diode, and a third diode,

wherein the variable capacitor and the first diode are sequentially connected in series between the input terminal and the output terminal;

wherein the third diode, the second diode, and the first diode are sequentially connected in series between the input terminal and the output terminal so that forward directions of the diodes are the same; and

wherein the variable capacitor, the second diode, and the third diode are connected in parallel between the input terminal and the first diode.

9. A rectifier circuit according to claim 8, wherein the variable capacitor is an n-channel MOS varactor.

10. The rectifier circuit according to claim 8, further comprising:

a capacitor connected in parallel with the first diode and the second diode.

11. A rectifier circuit according to claim 1, further comprising:

wherein the rectifier circuit comprises a first diode, a second diode, a third diode, a first input terminal, a second input terminal, a first output terminal, and a second output terminal,

wherein the plurality of diodes comprises a first diode, a second diode, and a third diode,

wherein the variable capacitor and the first diode are sequentially connected in series between the first input terminal and the first output terminal;

wherein the second diode and the first diode are sequentially connected in series between the second input terminal and the first output terminal so that forward directions of the diodes are the same; and

wherein the third diode, the variable capacitor, and the first diode are sequentially connected in series between the second output terminal and the first output terminal so that forward directions of the first diode and the third diode are the same.

12. A rectifier circuit according to claim 11, wherein the variable capacitor is an n-channel MOS varactor.

13. The rectifier circuit according to claim 11, further comprising:

a capacitor connected in parallel with the first diode and the second diode.

14. The rectifier circuit according to claim 11, further comprising:

a capacitor connected between the second diode and the second output terminal.

15. A rectifier circuit according to claim 1, further comprise:

wherein the rectifier circuit comprises a second variable capacitor, a first diode, a second diode, a third diode, a fourth diode, a first input terminal, a second input terminal, and an output terminal,

wherein the plurality of diodes comprises a first diode, a second diode, a third diode, and a fourth diode,

wherein the variable capacitor, the second variable capacitor, and the first diode are sequentially connected in series between the first input terminal and the output terminal;

wherein the variable capacitor, the third diode, the second diode, and the first diode are sequentially connected in series between the first input terminal and the output terminal;

wherein the fourth diode, the third diode, the second diode, and the first diode are sequentially connected in series between the second input terminal and the output terminal so that forward directions of the diodes are the same; and

wherein the second variable capacitor, the third diode, and the second diode are connected in parallel between the variable capacitor and the first diode.

16. A rectifier circuit according to claim 15, wherein the variable capacitor and the second variable capacitor are p-channel MOS varactors.

17. The rectifier circuit according to claim 15, further comprising:

a capacitor connected in parallel with the first diode and the second diode.

18. The rectifier circuit according to claim 15, further comprising:

a capacitor connected in parallel with the third diode and the fourth diode.

19. A rectifier circuit according to claim 1, further comprising:

wherein the rectifier circuit comprises

a second variable capacitor, a first diode, a second diode, a third diode, a fourth diode, a first input terminal, a second input terminal, a first output terminal, and a second output terminal,

wherein the plurality of diodes comprises a first diode, a second diode, a third diode, and a fourth diode,

wherein the second variable capacitor and the first diode are sequentially connected in series between the first input terminal and the first output terminal;

wherein the fourth diode, the third diode, the second diode, and the first diode are sequentially connected in series between the second output terminal and the first output terminal so that forward directions of the diodes are the same;

wherein the variable capacitor and the second variable capacitor which are sequentially connected in series are connected in parallel with the third diode and the second diode; and

wherein the second diode and the first diode are sequentially connected in series between the second input terminal and the first output terminal.

20. A rectifier circuit according to claim 19, wherein the variable capacitor and the second variable capacitor are p-channel MOS varactors.

21. The rectifier circuit according to claim 19, further comprising:

a capacitor connected in parallel with the first diode and the second diode.

22. The rectifier circuit according to claim 19, further comprising:

a capacitor connected in parallel with the third diode and the fourth diode.

23. A semiconductor device comprising:

a rectifier circuit for rectifying an AC voltage fed from an antenna, wherein the rectifier circuit includes a variable capacitor; and

a capacitance value of the variable capacitor is changed in accordance with an amplitude of the AC voltage.

24. A semiconductor device comprising:

an antenna and a rectifier circuit for rectifying an AC voltage fed from the antenna, wherein the rectifier circuit includes comprises a variable capacitor; and

a capacitance value of the variable capacitor is changed in accordance with an amplitude of the AC voltage.

25. A semiconductor device according to claim 24, wherein the rectifier circuit further comprises:

a first diode, a second diode, a first input terminal, a second input terminal, and an output terminal,

wherein the variable capacitor and the first diode are sequentially connected in series between the first input terminal and the output terminal; and

wherein the second diode and the first diode are sequentially connected in series between the second input terminal and the output terminal so that forward directions of the diodes are the same.

26. A semiconductor device according to claim 25, wherein the variable capacitor is a p-channel MOS varactor.

27. The semiconductor device according to claim 25, wherein the rectifier circuit further comprises:

a capacitor connected in parallel with the first diode and the second diode.

28. A semiconductor device according to claim 24, wherein the rectifier circuit further comprises:

a capacitor, a first diode, a second diode, a first input terminal, a second input terminal, and an output terminal,

wherein the capacitor and the first diode are sequentially connected in series between the first input terminal and the output terminal;

wherein the second diode and the first diode are sequentially connected in series between the second input terminal and the output terminal so that forward directions of the diodes are the same; and

wherein the variable capacitor and the second diode are connected in parallel between the second input terminal and the first diode.

29. A semiconductor device according to claim 28, wherein the variable capacitor is an n-channel MOS varactor.

30. The semiconductor device according to claim 28, wherein the rectifier circuit further comprises:

a resistor connected between the capacitor and the first diode.

31. A semiconductor device according to claim 24, wherein the rectifier circuit further comprises:

a first diode, a second diode, a third diode, an input terminal, and an output terminal,

wherein the variable capacitor and the first diode are sequentially connected in series between the input terminal and the output terminal;

wherein the third diode, the second diode, and the first diode are sequentially connected in series between the input terminal and the output terminal so that forward directions of the diodes are the same; and

wherein the variable capacitor, the second diode, and the third diode are connected in parallel between the input terminal and the first diode.

32. A semiconductor device according to claim 31, wherein the variable capacitor is an n-channel MOS varactor.

33. The semiconductor device according to claim 31, wherein the rectifier circuit further comprises:

a capacitor connected in parallel with the first diode and the second diode.

34. A semiconductor device according to claim 24, wherein the rectifier circuit further comprises:

a first diode, a second diode, a third diode, a first input terminal, a second input terminal, a first output terminal, and a second output terminal,

wherein the variable capacitor and the first diode are sequentially connected in series between the first input terminal and the first output terminal;

wherein the second diode and the first diode are sequentially connected in series between the second input terminal and the first output terminal so that forward directions of the diodes are the same; and

wherein the third diode, the variable capacitor, and the first diode are sequentially connected in series between the second output terminal and the first output terminal so that forward directions of the first diode and the third diode are the same.

35. A semiconductor device according to claim 34, wherein the variable capacitor is an n-channel MOS varactor.

36. The semiconductor device according to claim 34, wherein the rectifier circuit further comprises:

a capacitor connected in parallel with the first diode and the second diode.

37. The semiconductor device according to claim 34, wherein the rectifier circuit further comprises:

a capacitor connected between the second diode and the second output terminal.

38. A semiconductor device according to claim 24, wherein the rectifier circuit further comprises:

a second variable capacitor, a first diode, a second diode, a third diode, a fourth diode, a first input terminal, a second input terminal, and an output terminal,

wherein the variable capacitor, the second variable capacitor, and the first diode are sequentially connected in series between the first input terminal and the output terminal;

wherein the variable capacitor, the third diode, the second diode, and the first diode are sequentially connected in series between the first input terminal and the output terminal;

wherein the fourth diode, the third diode, the second diode, and the first diode are sequentially connected in series between the second input terminal and the output terminal so that forward directions of the diodes are the same; and

wherein the second variable capacitor, the third diode, and the second diode are connected in parallel between the variable capacitor and the first diode.

39. A semiconductor device according to claim 38, wherein the variable capacitor and the second variable capacitor are p-channel MOS varactors.

40. The semiconductor device according to claim 38, wherein the rectifier circuit further comprises:

a capacitor connected in parallel with the first diode and the second diode.

41. The semiconductor device according to claim 38, wherein the rectifier circuit further comprises:

a capacitor connected in parallel with the third diode and the fourth diode.

42. A semiconductor device according to claim 24, wherein the rectifier circuit further comprises:

a second variable capacitor, a first diode, a second diode, a third diode, a fourth diode, a first input terminal, a second input terminal, a first output terminal, and a second output terminal,

wherein the second variable capacitor and the first diode are sequentially connected in series between the first input terminal and the first output terminal;

wherein the fourth diode, the third diode, the second diode, and the first diode are sequentially connected in series between the second output terminal and the first output terminal so that forward directions of the diodes are the same;

wherein the variable capacitor and the second variable capacitor which are sequentially connected in series are connected in parallel with the third diode and the second diode; and

wherein the second diode and the first diode are sequentially connected in series between the second input terminal and the first output terminal.

43. A semiconductor device according to claim 42, wherein the variable capacitor and the second variable capacitor are p-channel MOS varactors.

44. The semiconductor device according to claim 42, wherein the rectifier circuit further comprises:

a capacitor connected in parallel with the first diode and the second diode.

45. The semiconductor device according to claim 42, wherein the rectifier circuit further comprises:

a capacitor connected in parallel with the third diode and the fourth diode.

46. A method for driving a semiconductor device comprising:

feeding an AC voltage from an antenna;

rectifying the AC voltage by a rectifier circuit including a variable capacitor; and

changing a capacitance value of the variable capacitor in accordance with an amplitude of the AC voltage.