Floating dc current source for a subscriber loop circuit

Details Floating dc current source for a subscriber loop circuit Floating dc current source for a subscriber loop circuit

1982-11-01

1985-04-16

Rubinson, Gene Z.

Electric power conversion systems

Phase conversion without intermediate conversion to d.c.

By dynamoelectric machine converter

179 16F, 179 70, 363 21, H04M 1900

Patent

active

045117632

ABSTRACT:
Under an off-hook condition a pulse width control circuit is periodically turned on by narrow pulses from a clock source. This initiates current flow from a primary dc source via the single primary winding of a transformer, and through power transistors connected in a Darlington configuration. A ramp voltage is developed across an emitter resistor of one of said power transistors and this voltage is feedback to said pulse width control circuit. When the ramp voltage reaches a predetermined value, the pulse width control circuit turns off the power transistors and the energy stored in the transformer is transferred by the collapsing magnetic field into alternating current in the secondary winding. This alternating current is rectified and filtered to provide loop current to the telephone subscriber loop. The voltage reflected from the secondary to the primary is stored in a peak detector circuit which operates to control the length of time during which the ramp voltage builds to its predetermined amplitude. The magnitude of this reflected voltage is a function of the loop resistance. Thus, a controlled loop current is provided which is dependent upon the loop resistance. When the loop resistance reaches a predetermined value, a breakdown diode in the output of the peak detector allows current to flow in an "idle power shutdown circuit" which interrupts the clock pulse input to the pulse width control circuit. This permits a reduction in power during the on-hook state.

REFERENCES:
patent: 4402039 (1983-08-01), Jirka
patent: 4429186 (1984-01-01), Gartner

Affiliated with

Also associated with

Rating

Floating dc current source for a subscriber loop circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Floating dc current source for a subscriber loop circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Floating dc current source for a subscriber loop circuit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1457907