Appeal No. 2004-0650 2
Application No. 09/894,265
utilized to detect when an electrical voltage signal has exceeded a
specified voltage.
Claim 1 is illustrative of the invention and reads as follows:
1. A circuit to monitor amplitude of an input signal, comprising:
(a) an active device to provide a current representative of
the amplitude of a repeating voltage input signal
connected to a source/emitter to the active device;
(b) a reference voltage connected to a gate/base of the
active device, the reference voltage independent of and
different from the input signal;
(c) a current source connected to a drain collector of the
active device;
(d) a comparator connected to a node between the
drain/collector of the active device and the current
source;
(e) a capacitor coupled to the node, suitable for filtering
the current representative of the amplitude of the
repeating voltage input signal;
wherein when the repeating voltage input signal is less than
the reference voltage minus a threshold voltage of the active
device, the active device conducts current representative of the
high frequency input signal, and
wherein when the conducting current is greater than the
current output from the current source, the voltage at a node
between the current source and the active device transitions, and
wherein when the voltage at the node transitions past a second
reference voltage input to the comparator, an output of the
comparator will transition.
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Last modified: November 3, 2007