Title:
OPERATIONAL AMPLIFIER
Document Type and Number:
Japanese Patent JP3662758
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To satisfactorily maintain both distortion characteristic and through- rate characteristic over a wide power supply voltage range as an operational amplifier.
SOLUTION: An operating current Idiff of a differential circuit 10 is controlled by a first current source circuit 50 and on the other hand an operating current Ils of a level shift circuit 20 is controlled by a second current source circuit 60. The first current source circuit 50 is constituted so as to keep the operating current Idiff almost constant even in the case of changing a power supply voltage, such that the through-rate characteristic of the operational amplifier can be satisfactorily maintained over a prescribed power supply voltage range. The second current source circuit 60 controls the operating current Ils, so as to keep the difference between the power supply voltage and a level shift voltage V1 almost constant, even in the case of changing the power supply voltage so that the distortion characteristics of the operational amplifier cannot be degraded over a prescribed power supply voltage ranges. Therefore, both the distortion characteristics and through rate characteristics of the operational amplifier are satisfactorily maintained over the wide power supply voltage ranges.
Inventors:
Takeyuki Takayama
Application Number:
JP1801899A
Publication Date:
June 22, 2005
Filing Date:
January 27, 1999
Export Citation:
Assignee:
Matsushita Electric Industrial Co., Ltd
International Classes:
H03F3/45; H03F1/30; H03F1/32; (IPC1-7): H03F3/45; H03F1/30; H03F1/32
Domestic Patent References:
| JP4185005A | ||||
| JP2146807A | ||||
| JP1137808A | ||||
| JP59196613A | ||||
| JP6350355A | ||||
| JP10065460A |
Attorney, Agent or Firm:
Hiroshi Maeda
Hiroshi Koyama
Hiroshi Koyama