US 12,034,405 B2
Circuit device and oscillator
Takehiro Yamamoto, Matsumoto (JP)
Assigned to SEIKO EPSON CORPORATION, (JP)
Filed by Seiko Epson Corporation, Tokyo (JP)
Filed on Dec. 27, 2021, as Appl. No. 17/562,065.
Claims priority of application No. 2020-218552 (JP), filed on Dec. 28, 2020.
Prior Publication US 2022/0209716 A1, Jun. 30, 2022
Int. Cl. H03B 28/00 (2006.01); G06F 1/02 (2006.01); H03H 9/19 (2006.01)
CPC H03B 28/00 (2013.01) [G06F 1/022 (2013.01); H03H 9/19 (2013.01); H03B 2200/0034 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A circuit device comprising:
an oscillation circuit which is electrically coupled to a first node to electrically be coupled to one end of a resonator and a second node to electrically be coupled to another end of the resonator, the oscillation circuit being configured to oscillate the resonator to generate an oscillation signal, the oscillation circuit including:
an oscillation capacitor having one end coupled to the first node;
an oscillation resistor having:
one end coupled to another end of the oscillation capacitor; and
another end coupled to the second node;
a stationary capacitance capacitor having one end coupled to the first node, a capacitance value of the stationary capacitance capacitor being fixed; and
a variable capacitance element having one end coupled to another end of the stationary capacitance capacitor, a capacitance value of the variable capacitance element being variable;
a waveform shaping circuit which is coupled to the first node, to which the oscillation signal is input from the first node, and which is configured to output a clock signal obtained by performing waveform shaping on the oscillation signal; and
a duty adjustment circuit configured to:
supply the first node with a bias voltage which is variably adjusted based on adjustment data to thereby adjust a duty ratio of the clock signal; and
supply a reference voltage to the other end of the variable capacitance element.