Ramp wave output circuit, analog/digital conversion circuit, and camera
First Claim
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1. A ramp wave output circuit, comprising:
- a ramp wave generation circuit generating a ramp wave;
a low-pass filter having a variable cutoff frequency, which receives the ramp wave,a replica filter of the low-pass filter; and
a first comparator comparing an output of the replica filter and a predetermined voltage,wherein the low-pass filter operates at a first cutoff frequency for a predetermined time period after the receipt of the ramp wave, and operates at a second cutoff frequency, which is larger than the first cutoff frequency, after the predetermined time period has passed, andthe predetermined time period is determined based on a comparison result by the first comparator.
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Abstract
A ramp wave output circuit includes a ramp wave generation circuit generating a ramp wave, and a low-pass filter having a variable cutoff frequency, which receives the ramp wave. The low-pass filter operates at a first cutoff frequency for a predetermined time period after the receipt of the ramp wave, and at a second cutoff frequency, which is larger than the first cutoff frequency, after the predetermined time period has passed.
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Citations
3 Claims
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1. A ramp wave output circuit, comprising:
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a ramp wave generation circuit generating a ramp wave; a low-pass filter having a variable cutoff frequency, which receives the ramp wave, a replica filter of the low-pass filter; and a first comparator comparing an output of the replica filter and a predetermined voltage, wherein the low-pass filter operates at a first cutoff frequency for a predetermined time period after the receipt of the ramp wave, and operates at a second cutoff frequency, which is larger than the first cutoff frequency, after the predetermined time period has passed, and the predetermined time period is determined based on a comparison result by the first comparator. - View Dependent Claims (2, 3)
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Specification