Title:
SIGNAL CHANGE-OVER DEVICE
Document Type and Number:
Japanese Patent JPH03178216
Kind Code:
A
Abstract:
PURPOSE: To protect over-voltage to transition by providing high attenuation at an off state by providing a first and a second switches with a signal switching device, responding to a closed state of the second switch by a bias circuit network and biasing a breakdown device to a bias voltage level previously decided. CONSTITUTION: First and the second switches 14, 30 are continuously connected between a signal input terminal 10 and a signal output terminal 12. The first switch 14 consists of an L-shaped attenuator provided with serial shunts 16, 18, containing an impedance and a parallel shunt containing a breakdown device 22. The bias circuit network connected to the attenuator controls the bias of the breakdown device 22 to be operated at a prescribed current conducting level, when a second switch 30 is open and to be operated at a prescribed bias voltage level when the second switch 30 is closed. Consequently, the attenuation at the off-state is increased, over-voltage and past current are protected to the transition state of the input, and an output direct current level is supplied when the second switch is closed.
Inventors:
JIIN KAARU SENDORUUETSUKU
Application Number:
JP32135590A
Publication Date:
August 02, 1991
Filing Date:
November 27, 1990
Export Citation:
Assignee:
THOMSON CONSUMER ELECTRONICS
International Classes:
H03F3/72; H03K17/00; H03K17/567; H03K17/693; H03K17/74; H03K17/76; (IPC1-7): H03K17/56; H03K17/693; H03K17/74
Domestic Patent References:
| JP44014852A |
Attorney, Agent or Firm:
Katsunori Watanabe