Peak hold circuit with improved linearity
First Claim
1. Apparatus for detecting peak values in an input signal, said apparatus comprising:
- operational amplifier means having a first amplifier input for receiving said input signal, a second amplifier input for receiving a feedback signal, and an amplifier output for providing an amplified signal;
first transistor means for receiving said amplified signal and having a first transistor output for providing said feedback signal;
current sink means coupled to said first transistor output for drawing a current from said first transistor means so that said feedback signal is continually provided from said first transistor means to said second amplifier input;
peak hold capacitor means for storing a charge representing a peak amplitude of said input signal;
second transistor means for receiving said amplified signal and for coupling said amplified signal to said peak hold capacitor means; and
discharge means for discharging said peak hold capacitor means.
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Accused Products
Abstract
A peak hold circuit includes an operational amplifier in a continually closed feedback loop and a peak hold capacitor with a discharge path. An input signal is received at a first input of the amplifier, and the output of the amplifier is fed to a first transistor then fed back therefrom to a second input of the amplifier. A current sink is coupled to the first transistor for drawing a current therefrom so that the feedback signal is continually provided to the second amplifier input, ensuring that the amplifier is in a continually closed feedback loop. The output of the amplifier is supplied to the peak hold capacitor through a second transistor.
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Citations
10 Claims
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1. Apparatus for detecting peak values in an input signal, said apparatus comprising:
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operational amplifier means having a first amplifier input for receiving said input signal, a second amplifier input for receiving a feedback signal, and an amplifier output for providing an amplified signal; first transistor means for receiving said amplified signal and having a first transistor output for providing said feedback signal; current sink means coupled to said first transistor output for drawing a current from said first transistor means so that said feedback signal is continually provided from said first transistor means to said second amplifier input; peak hold capacitor means for storing a charge representing a peak amplitude of said input signal; second transistor means for receiving said amplified signal and for coupling said amplified signal to said peak hold capacitor means; and discharge means for discharging said peak hold capacitor means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification