US 11,722,161 B2
Generating a digital modulation signal and an analog modulation signal according to an input signal of the frequency modulation circuit
Xunyu Zhu, Hangzhou (CN); and Yan Ye, Hangzhou (CN)
Assigned to Silergy Semiconductor Technology (Hangzhou) LTD, Hangzhou (CN)
Filed by Silergy Semiconductor Technology (Hangzhou) LTD, Hangzhou (CN)
Filed on Aug. 24, 2022, as Appl. No. 17/894,349.
Application 17/894,349 is a continuation of application No. 17/237,236, filed on Apr. 22, 2021, granted, now 11,438,018.
Claims priority of application No. 202010361701.3 (CN), filed on Apr. 30, 2020.
Prior Publication US 2022/0407545 A1, Dec. 22, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H04B 1/04 (2006.01); H04B 1/00 (2006.01); H04B 1/66 (2006.01)
CPC H04B 1/04 (2013.01) [H04B 1/0014 (2013.01); H04B 1/667 (2013.01); H04B 2001/0491 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A frequency modulation circuit, comprising:
a) a modulation circuit configured to generate a digital modulation signal and an analog modulation signal according to an input signal of the frequency modulation circuit;
b) a phase-locked loop having a voltage-controlled oscillator configured to receive a reference frequency, and to adjust capacitor arrays of the voltage-controlled oscillator according to the analog modulation signal and the digital modulation signal, in order to modulate a frequency of an output signal of the voltage- controlled oscillator; and
c) wherein the capacitor arrays comprises a switched capacitor array and a variable capacitor array, wherein the variable capacitor array comprises variable capacitors, and wherein the capacitance value of the variable capacitor array is adjusted according to low-digit codes of the input signal and an error information between the output signal and the reference frequency.