Title:
FILTER CIRCUIT
Document Type and Number:
Japanese Patent JP3175995
Kind Code:
B2
Abstract:
PURPOSE: To realize the filter circuit having no externally mounted component in the case of circuit integration.
CONSTITUTION: Compression and expansion is applied to an output i1 of an amplifier gm1 by active resistors rD1, rD2 and an amplifier gm2 to obtain a current iout proportional to the current i1 thereby controlling charging/ discharging of a capacitor C1. Thus, the current iout for controlling the C1 is reduced depending on the setting of a current ratio iout/i1 (=I1/I2) to make the size of the capacitor C1 small. Moreover, an amplifier gm3 receives an output voltage vout as a differential input and converts it into a current i3 and it is compressed/expanded by the active resistors rD1, rD2 and the amplifier gm2 and the resistive impedance is made small depending on a current ratio iout/i1 (=I3/I2).
Inventors:
Suzuki Osamu
Application Number:
JP11736493A
Publication Date:
June 11, 2001
Filing Date:
May 19, 1993
Export Citation:
Assignee:
Toshiba Corporation
International Classes:
H03H11/04; (IPC1-7): H03H11/04
Domestic Patent References:
| JP2159112A | ||||
| JP514074A |
Attorney, Agent or Firm:
Kazuo Sato (3 others)