Title:
POSITIVE CHARGING PULSE SENDING CIRCUIT
Document Type and Number:
Japanese Patent JPH01112807
Kind Code:
A
Abstract:
PURPOSE:To reduce charging noise with a simple circuit by using a capacitor and a resistor so as to smooth a charging pulse transmission control signal and using 1st and 2nd transistors(TRs) so as to send a smooth positive charging pulse. CONSTITUTION:With a voltage of a charging pulse sending control signal inputted to an input terminal 28 going to a ground (earth) level, a base voltage of the 1st TR 23 is decreased by a time constant depending on the capacitor 25 and resistors 26, 27. When the base voltage is lower than the base voltage of the 2nd TR 21, the 2nd TR 21 is turned on and the 1st TR 23 is turned off. In selecting the change in the base potential of the TR as nearly 0.6V, the collector current of the 2nd TR 21 changes smoothly both for leading and trailing states. In this case, in selecting resistors 17, 18 of the final stage properly for the constant current circuit, the base current waveform is the collector current waveform of the final stage as it is and the collector current of the waveform is outputted to a charging pulse output terminal 11.
Inventors:
SHIMOMA MASASHI
Application Number:
JP26983887A
Publication Date:
May 01, 1989
Filing Date:
October 26, 1987
Export Citation:
Assignee:
NEC CORP
International Classes:
H04M15/00; H03K4/00; H03K4/94; (IPC1-7): H03K4/00; H03K4/94; H04M15/00
Attorney, Agent or Firm:
Masaki Yamakawa (2 outside)
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