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Patent Searching and Data


Title:
STEP ATTENUATOR
Document Type and Number:
Japanese Patent JPH0758563
Kind Code:
A
Abstract:

PURPOSE: To make a chip area small, to reduce cost and to improve yield by using a plural switches so as to switch over plural voltage levels and inputting the voltage level to a voltage amplifier of a high input impedance and receiving a signal passing through the switch at a high input impedance.

CONSTITUTION: The attenuator is made of a fixed attenuation generating section 4 formed by connecting resistors 4-1-4-n in series, a fixed attenuation selection section 5 comprising n-set of FET switches 5-1-5-n, an amplifier section 6 connecting to an output of the fixed attenuation selection section 5 in which the FET switches are connected in common and amplifying the voltage output and a control signal generating section 3 connecting to control terminals of the n-set of FET switches of the fixed attenuation selection section 5 and applying a control signal to close only one of the FET switches. Then plural voltage levels obtained by dividing a voltage converted from input power are switched by the plural switches 4-1 to 4-n and the selected voltage is received by a voltage amplifier 6 with a high input impedance.


Inventors:
SHIMIZU TOSHIHIKO
HIGUCHI MASAHIRO
Application Number:
JP20388993A
Publication Date:
March 03, 1995
Filing Date:
August 18, 1993
Export Citation:
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Assignee:
HITACHI LTD
International Classes:
H03G3/02; H03H7/25; H03H11/24; (IPC1-7): H03G3/02; H03H11/24
Attorney, Agent or Firm:
Ogawa Katsuo