Title:
DIFFERENTIAL AMPLIFIER
Document Type and Number:
Japanese Patent JP3308596
Kind Code:
B2
Abstract:
PURPOSE: To execute the active filter of low noise with a little current consumption by using both of the attenuation processing of a current gain due to a current mirror circuit and the linear range extension processing of an emitter coupled pair
CONSTITUTION: When the ratio of the input current to the output current of a current mirror circuit 102 is set to n:1, a transconductance Gm is attenuated to 1/n. Then, a cut-off frequency f0 is turned to Gm/2π.n.C as a ratio between Gm/n and a capacity value C and turned to 1/n in comparison with Gm/2π.C. Therefore, currents i11, i12) and i13 to flow to emitter coupled pairs Q11Q12, Q13Q14 and Q15Q16 are made n-fold, and the equivalent input converting noise voltage is reduced to 1/n1/2. Therefore, noise from the filter can be reduced to 1/n1/2 while keeping the capacity value C as it is. Further, the active filter of low noise can be executed with a little current consumption by using both of the attenuation processing of the current gain due to the circuit 102 and the linear range extension processing of the emitter coupled pair.
Inventors:
Mikio Koyama
Application Number:
JP22427892A
Publication Date:
July 29, 2002
Filing Date:
August 24, 1992
Export Citation:
Assignee:
Toshiba Corporation
International Classes:
H03F1/26; H03F3/343; H03F3/347; H03F3/45; H03H11/04; (IPC1-7): H03F3/343; H03F1/26; H03F3/45; H03H11/04
Domestic Patent References:
| JP470204A | ||||
| JP6427707U |
Attorney, Agent or Firm:
Kazuo Sato (3 others)