Title:
EXTENSION CIRCUIT
Document Type and Number:
Japanese Patent JP3147986
Kind Code:
B2
Abstract:
PURPOSE: To provide output signals having the quadratic characteristics of input signal levels by differentially amplifying analog input signals and outputs respectively amplifying the analog input signals with a gain control circuit for which the amplification factor is changed corresponding to the change of a control signal.
CONSTITUTION: An analog input signal Vin is amplified by an operational amplifier 115 and inputted through a rectifier circuit REC to an average circuit MEAN. The MEAN compares the output of the REC with a reference voltage and corresponding to the compared result, the control signal is supplied to voltage variable resistors RV114 and RV124 of gain control circuits Gc1 and Gc2. On the other hand, a differential amplifier AMP 135 differentially amplifies the Vin and a signal amplifying the Vin with an AMP 25 having the same amplification factor as an AMP 115 and outputs a signal extending the Vin. Thus, the circuit having the square characteristic of the input signal level easily made into an LSI can be provided.
Inventors:
Tokio Sato
Application Number:
JP12500892A
Publication Date:
March 19, 2001
Filing Date:
May 18, 1992
Export Citation:
Assignee:
Oki Electric Industry Co., Ltd.
International Classes:
H03G1/00; G06G7/20; H03G7/00; H04B1/64; (IPC1-7): H03G7/00; H04B1/64
Domestic Patent References:
| JP5417610A | ||||
| JP1269186A | ||||
| JP1318308A | ||||
| JP55104143A | ||||
| JP5545230A | ||||
| JP5549010A | ||||
| JP63107065U |
Attorney, Agent or Firm:
Kenji Ohnishi
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