在系統晶片化的時代，時序電路儼然就是數位電路的中樞，振盪器更在其中扮演一個關鍵性的元件。目前3C產品的蓬勃發展中，皆以輕、薄、省電與節省成本為最大訴求，在應用上，因此在節省面積與降低功率消耗的同時，加入了各種頻率調整的功能，而使系統依然保持著穩定的操作便是此研究目的。 系統晶片會隨著製程與溫度偏異而產生飄移，電路上會產生非理想的偏異，會造成系統上的不穩定，進而造成晶片的不正常工作，更嚴重而導致晶片的損壞，如何設計出一個不隨製程與溫度變異的可調式振盪器便是研究中一個重要的議題，在電路的設計上使用CMOS大幅降低功率的損耗，因此，此論文目標為設計出一個具製程及溫度補償之頻率可調式電流控制振盪器電路。 整體電路可分為兩大部分，第一部分為設計偏壓參考電流源，其中包含了正溫度係數電流與負溫度係數電流來完成溫度補償。接著利用輸出電流調整電路來調整頻率與補償因為製程所產生的變異。第二部份為五級單端延遲單位所組成的環型振盪器。在正常供應電壓1.8V操作環境下，前模擬的溫度變化在-25~75℃時四種頻率其溫度變異係數皆小於88ppm/℃。最後我們所提出之具製程及溫度補償之頻率可調式電流控制振盪器電路，後模擬的溫度變化在-25~75℃時四種頻率溫度變異係數皆小於96 ppm/℃。功率消耗在各種頻率、製程及溫度變異下，皆小於92.9 uW，加入output buffer時，在各種頻率、製程及溫度變異下，功率消耗皆小於520.9 uW。 This thesis presents two oscillators with detecting process and temperature (PT) drift working in 1.8V supply voltage for 10、20、30、40-MHz clock oscillator. The oscillator circuits are composed of current reference circuit and ring oscillator. This paper describes a circuit, which generates a low temperature-dependent bias currents. The current reference circuit is composed of complementary-to-absolute -temperature (CTAT) and a proportional-to-absolute-temperature (PTAT) to compensated temperature variation. And output current adjustment circuit is used to overcome process variation. In this paper, low temperature coefficient reference is presented. The circuit is firstly employed to generate a current reference with temperature compensation, then, supply current to the current controlled ring oscillator (CCO). There are four different oscillation frequency with temperature and process compensation has been completed, they are 10MHz, 20MHz, 30MHz and 40MHz respectively. The proposed circuit has been design by a 0.18um CMOS technology process and using computer simulation to evaluate the thermal drift of the reference current. In post-simulation, the temperature coefficient of the proposed CCO is less than 68 ppm/℃ in the variety of process variation and temperature range between -25 and 75℃ at 10MHz. In the 20MHz, 30MHz and 40MHz oscillation frequency, the temperature coefficients are 83 ppm/℃, 96 ppm/℃ and 96 ppm/℃ respectively. Power consumption is less than 92.9 uW without output buffer and less than 520.9 uW with output buffer.
