Crown BCA Supplementary Manual
Text of the manual
] Balanced Current Amplifier
Reinventing the Power Amplifier - BCA
THE BALANCED CURRENT AMPLIFIER - A NEW
PARADIGM FOR THE 21ST CENTURY
In 1931 Loy Barton, a research worker employed by
David Sarnoff , unearthed the paradigm that has domi-
nated all electronic power amplifiers used for audio re-
production and industrial power to this present day. Many
incre
] Balanced Current Amplifier
is decreased by the same amount. Both pulses remain
centered on each other or balanced in time. The result
is that the difference ripple current has a minimum fre-
quency which is twice the operating frequency of the
individual switches.
The frequency doubling character of the output is re-
markable and further allows advancement
] Balanced Current Amplifier
The simplest combining method is to join the output sig-
nals at a single circuit node. This is the method used in
all power stages that are referred to in the jargon as a
totem-pole, half-bridge or single-ended push-pull de-
sign. While combining at a node is the simplest method,
it was not the method first used to produce push-
] Balanced Current Amplifier
cycle). When the Sp and Sn switches are both closed
during interval Tp (or Tn) the main output inductor cur-
rent magnitudes increase at a rate of Vcc/L where
L=Lp=Ln. When the switches are both off during the in-
terval following Tp (equal to Tp=Ts-Tp), the inductor volt-
age is reversed and the output currents ramp down at
the
] Balanced Current Amplifier
When the amplifier is at quiescent state with no output
voltage, the equivalent switch will always be at the ground
position as the switches are operating in unison, either
being on or off with a 50% duty cycle. In other words
Tp=Tn=Ts/2 where Ts is the inverse of the switching fre-
quency, the switching period. If Tp is the peri
