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研究了一款单片CMOS LC压控振荡器(VCO)。除可变电容和开关电容阵列外,设计中还应用了二叉树的原理。多频段VCO自适应选择最优工作频段,将压控电压置于预先设定的范围内,谐振频率放在该频段的中心附近,提高了VCO的工作稳定性。设计难点在于如何控制压控电压位于合适的范围。将该VCO应用在锁相环(PLL)中,对锁相环芯片测试的结果表明,当压控电压为1~2 V时,锁相环能够快速锁定,频率输出范围为600~1 300 MHz。电荷泵的NMOS和PMOS匹配最佳,相位噪声最好。自适应频段选择技术还提高了锁相环的工作可靠性,强制控制电压进入设定区间,保证了锁相环可靠入锁,在高、低温下也不会发生失锁。
Studied a monolithic CMOS LC voltage controlled oscillator (VCO). In addition to variable capacitors and switched capacitor arrays, the design also applies the principle of binary trees. Multi-band VCO adaptive selection of the optimal operating frequency band, the voltage-controlled voltage is placed within the pre-set range, the resonant frequency on the center of the band around to improve the VCO’s work stability. The design difficulty lies in how to control the voltage-controlled voltage in the proper range. The application of the VCO in a phase-locked loop (PLL), the PLL chip test results show that when the voltage-controlled voltage of 1 ~ 2 V, the PLL can quickly lock the frequency output range of 600 ~ 1 300 MHz . The charge pump NMOS and PMOS match the best phase noise best. The adaptive frequency band selection technique also improves the reliability of the phase-locked loop, forces the control voltage into the set interval, ensures the reliable locking of the phase-locked loop, and prevents loss of lock at high and low temperatures.