Title:
TRANSMISSION INPUT CIRCUIT
Document Type and Number:
WIPO Patent Application WO/2010/038480
Kind Code:
A1
Abstract:
Provided is a transmission input circuit including: a current detection resistor which inputs a line current flowing in a transmission line so as to generate a line current detection voltage; a constant current circuit for generating a predetermined reference current; a first switch which performs a switching operation at an empty timing when no transmission current is flowing from a child device and supplies the reference current and a load current from the constant current circuit to the current detection resistor so as to generate a reference voltage by adding a threshold voltage corresponding to the reference current to the load current detection voltage; a capacitor for sample hold of the reference voltage in synchronization with the first switch; and a comparator having one input terminal to which the line current detection voltage generated by the current detection resistor is inputted and the other input terminal to which the reference voltage is inputted, so as to output as a transmission current detection signal, a voltage component of the line current detection voltage exceeding the reference voltage.
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Inventors:
KURIMOTO MITSUHIRO (JP)
Application Number:
PCT/JP2009/005116
Publication Date:
April 08, 2010
Filing Date:
October 02, 2009
Export Citation:
Assignee:
HOCHIKI CO (JP)
KURIMOTO MITSUHIRO (JP)
KURIMOTO MITSUHIRO (JP)
International Classes:
G08B17/00; G08B25/00; G08B29/06; H04Q9/00
Foreign References:
| JP2004102888A | 2004-04-02 | |||
| JPS62276694A | 1987-12-01 |
Other References:
See also references of EP 2352134A4
Attorney, Agent or Firm:
SHIGA, Masatake et al. (JP)
Masatake Shiga (JP)
Masatake Shiga (JP)
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