Title:
PWM CONTROL CIRCUIT AND MEDICAL IMAGE DIAGNOSTIC APPARATUS
Document Type and Number:
Japanese Patent JP2021052229
Kind Code:
A
Abstract:
To make it possible to generate a high resolution PWM signal while using a realistic clock.SOLUTION: A PWM control circuit according to an embodiment includes an oscillator, a counter, a first comparator circuit, a saw-tooth waveform generation circuit, a sample and hold circuit, a D/A converter, and a second comparator circuit. The counter counts signals of the oscillator. The first comparator circuit compares a count value of the counter with a set count value. The saw-tooth waveform generation circuit operates in synchronization with the counter by receiving a coincidence signal output from the first comparator circuit to generate a saw-tooth waveform as an analog signal. The sample and hold circuit holds a peak value of the saw-tooth waveform. The D/A converter uses output of the sample and hold circuit as a reference. The second comparator circuit outputs a PWM signal on the basis of comparison between the saw-tooth waveform and output of the D/A converter.SELECTED DRAWING: Figure 7
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Inventors:
ISHIYAMA FUMIO
FUKUHARA MANABU
FUKUHARA MANABU
Application Number:
JP2019172137A
Publication Date:
April 01, 2021
Filing Date:
September 20, 2019
Export Citation:
Assignee:
CANON MEDICAL SYSTEMS CORP
International Classes:
H03K7/08; A61B5/055; H02M3/155; H05G1/10
Attorney, Agent or Firm:
Sakai International Patent Office