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Phantom Voltage Source

IP.com Disclosure Number: IPCOM000122836D
Original Publication Date: 1998-Jan-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Barn, B: AUTHOR

Abstract

This invention shows a circuit used to generate a low power voltage source typically required for powering high quality microphones. The circuit is devised such that the low frequency audible noise performance of the voltage source is superior even in the presence of digital noise. The circuit is shown in the schematic diagram.

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Phantom Voltage Source

      This invention shows a circuit used to generate a low
power voltage source typically required for powering high quality
microphones.  The circuit is devised such that the low frequency
audible noise performance of the voltage source is superior even in
the presence of digital noise.  The circuit is shown in the schematic
diagram.

      The output voltage-phantom voltage source - is the input
voltage multiplied by the duty cycle of the signal driving the
Transistor.  Components L1, D1, C2, and the transistor make up a
conventional voltage boost circuit.

      This circuit is part of a larger System from which a signal is
derived to operate the Transistor in synchronism.  Operating the
Transistor synchronously with the rest of the system eliminates the
beat frequency and its harmonics from appearing at the output.  This
scheme results in clean voltage source in the audible frequency
range.  Of course, the switching frequency noise appears at the
output but this is out of the audible range and thus not of any
concern.

      The duty of the Synchronous clock is not exactly as required to
attain the desired output voltage but it is close.  To accommodate
the inaccuracy of the duty cycle R1 functions as a dissipative
element to reduce the voltage at C1 the input to the boost regulator.
The combination of R1 and C1 also function as an input filter.
Furthermore, R1 functions as limiting component to guard against
shorts at the...