Title:
可変時定数回路及びこれを用いたフィルタ回路
Document Type and Number:
Japanese Patent JP4098701
Kind Code:
B2
Abstract:
A variable time constant circuit includes an inverting amplifier which has an amplifier input terminal and an amplifier output terminal connected to a signal output terminal and inverts a signal inputted to the amplifier input terminal, a first and a second resistor which are connected in series between the signal input terminal and the amplifier input terminal, a capacitor connected between the amplifier input terminal and the amplifier output terminal, a field effect transistor including a gate terminal connected to a junction point of the first and second resistors, a source terminal kept at a constant potential, and a drain terminal connected to the amplifier input terminal, the transistor flowing a current through the drain terminal according to a voltage between the gate terminal and the source terminal, and a control circuit which controls a voltage-current conversion ratio of the transistor according to a time constant control signal.
Inventors:
Daisuke Kurose
Tetsuro Itakura
Kind of Ito
Tetsuro Itakura
Kind of Ito
Application Number:
JP2003372442A
Publication Date:
June 11, 2008
Filing Date:
October 31, 2003
Export Citation:
Assignee:
Toshiba Corporation
International Classes:
H03F3/45; H03H11/04; G06G7/18; H03F1/00; H03F3/345; H03H11/12; H03H11/24; H03H11/32; H04B1/10
Domestic Patent References:
| JP63136708A | ||||
| JP63136707A | ||||
| JP2145009A | ||||
| JP2000508868A |
Foreign References:
| US5880634 | ||||
| US4780690 |
Attorney, Agent or Firm:
Takehiko Suzue
Satoshi Kono
Makoto Nakamura
Kurata Masatoshi
Sadao Muramatsu
Ryo Hashimoto
Satoshi Kono
Makoto Nakamura
Kurata Masatoshi
Sadao Muramatsu
Ryo Hashimoto