CN-122001300-A - Linear wide tuning voltage range LC oscillator with temperature compensation

CN122001300ACN 122001300 ACN122001300 ACN 122001300ACN-122001300-A

Abstract

The invention discloses a linear LC oscillator with temperature compensation and wide tuning voltage range, which belongs to the field of integrated circuits and comprises PMOS (P-channel metal oxide semiconductor) transistors Q1 and Q2, an array capacitor unit, a variable capacitor unit, inductors L1 and L2 and an array resistor unit, wherein the design of the linear LC oscillator with temperature compensation variable capacitor can be realized by controlling voltage V CTRL from 0V to 2.5V. The invention adopts BICMOS process to design the flow sheet, the power supply voltage is 3.3V, the frequency adjustment range is 2.5GHz-3.3GHz, the phase noise is-139 dBc/Hz at 2.7GHz, the variable capacitance adopts linear voltage interpolation temperature compensation technology, the capacitance value of the variable capacitance unit within the control voltage V CTRL 0-2.5V is linearly changed, and the frequency offset is smaller than 0.5M within the temperature change range of-55 ℃ to 125 ℃.

Inventors

WANG BAIKANG
QIN ZHANMING
YANG JUNHAO
ZHANG LIYI
SUN WENJUN
FAN HAIYU
ZHANG BIN

Assignees

中国电子科技集团公司第五十八研究所

Dates

Publication Date: 20260508
Application Date: 20260108

Claims (5)

1. An LC oscillator with temperature compensated linear wide tuning voltage range, comprising: the PMOS tubes Q1 and Q2 provide negative resistance for the LC oscillator through a cross-coupling connection mode of the PMOS tubes Q1 and Q2, and provide energy consumed by the core oscillator; The array capacitor unit selects different capacitors according to 7-bit switch control signals S witch <6:0>, changes the capacitance value of the LC oscillator during oscillation, and realizes large-range rough adjustment of oscillation frequency; The variable capacitance unit adopts a voltage linear interpolation temperature compensation technology to realize that the capacitance value of the variable capacitance unit is linearly changed within a wide control voltage V CTRL adjusting range, an LC oscillator works within a relatively wide tuning range after frequency locking is realized, a terminal voltage temperature curve of the variable capacitance is controlled, the capacitance value of the variable capacitance is reduced along with temperature rise, the influence of the fixed capacitance on the rise of the capacitance value along with the temperature rise is compensated, the change of the oscillation frequency within the whole temperature range is smaller, and continuous locking of the system within the whole temperature range is realized; Inductors L1 and L2 provide the inductance L value of the LC oscillator and act together with the total capacitance in the circuit to realize circuit oscillation; The array resistor unit selects different LOAD resistors according to 6-bit switch signals LOAD <5:0>, controls the total current of the circuit when the LC oscillator works, controls the output swing amplitude of the LC oscillator, and selects the optimal current and voltage to realize the optimization of the phase noise of the oscillator circuit.
2. The LC oscillator with temperature compensated linear wide tuning voltage range of claim 1, wherein the source of the PMOS transistor Q1 and the source of the PMOS transistor Q2 are connected to a power supply VDD, the gate of the PMOS transistor Q1 and the drain of the PMOS transistor Q2 are commonly connected to the B terminal, and the drain of the PMOS transistor Q1 and the gate of the PMOS transistor Q2 are commonly connected to the a terminal; The two ends of the array capacitor unit are connected to the end A and the end B, the two ends of the variable capacitor unit are connected to the end A and the end B, the two ends of the inductor L1 are connected to the end A and the end C, the two ends of the inductor L2 are connected to the end B and the end C, and the two ends of the array resistor unit are connected to the end C and the GND.
3. The LC oscillator with temperature compensated linear wide tuning voltage range of claim 1, wherein the variable capacitance unit comprises fixed capacitances C1 to C8, variable capacitances C9 to C16, resistors R1 to R11, PMOS tube Q3; The source stage and the gate stage of the PMOS tube Q3 are connected and connected to the VDD, and the drain stage of the PMOS tube Q3 is grounded GND through a resistor R9, a resistor R10 and a resistor R11 in sequence; The first end of the capacitor C1 is connected with the end A, the second end of the capacitor C1 is connected with the first end of the capacitor C2 sequentially through a resistor R1 and a resistor R2, the second end of the capacitor C2 is connected with the end B, one end of the variable capacitor C9 is connected with a connecting point of the capacitor C1 and the resistor R1, one end of the variable capacitor C10 is connected with a connecting point of the resistor R2 and the capacitor C2, and the other end of the variable capacitor C9 and the other end of the variable capacitor C10 are commonly connected to VDD; The first end of the capacitor C3 is connected with the end A, the second end of the capacitor C3 is connected with the first end of the capacitor C4 sequentially through a resistor R3 and a resistor R4, the second end of the capacitor C4 is connected with the end B, one end of the variable capacitor C11 is connected with a connection point of the capacitor C3 and the resistor R3, one end of the variable capacitor C12 is connected with a connection point of the resistor R4 and the capacitor C4, and the other end of the variable capacitor C11 and the other end of the variable capacitor C12 are commonly connected to a connection point of a drain stage of the PMOS tube Q3 and the resistor R9; the first end of the capacitor C5 is connected with the end A, the second end of the capacitor C5 is connected with the first end of the capacitor C6 sequentially through a resistor R5 and a resistor R6, the second end of the capacitor C6 is connected with the end B, one end of the variable capacitor C13 is connected with a connecting point of the capacitor C5 and the resistor R5, one end of the variable capacitor C14 is connected with a connecting point of the resistor R6 and the capacitor C6, and the other end of the variable capacitor C13 and the other end of the variable capacitor C14 are commonly connected to a connecting point of the resistor R9 and the resistor R10; The first end of the capacitor C7 is connected with the end A, the second end of the capacitor C7 is connected with the first end of the capacitor C8 sequentially through a resistor R7 and a resistor R8, the second end of the capacitor C8 is connected with the end B, one end of the variable capacitor C15 is connected with a connecting point of the capacitor C7 and the resistor R7, one end of the variable capacitor C16 is connected with a connecting point of the resistor R8 and the capacitor C8, and the other end of the variable capacitor C15 and the other end of the variable capacitor C16 are commonly connected to a connecting point of the resistor R10 and the resistor R11; The control voltage V CTRL is connected to the connection point of the resistor R1 and the resistor R2, the connection point of the resistor R3 and the resistor R4, the connection point of the resistor R5 and the resistor R6, and the connection point of the resistor R7 and the resistor R8.
4. The LC oscillator with temperature compensated linear wide tuning voltage range of claim 3, wherein the control voltage V CTRL is changed in magnitude to change the voltage across the variable capacitance, change the capacitance of the variable capacitance unit, change the capacitance of the LC oscillator during oscillation, and achieve small-range fine tuning of the oscillation frequency.
5. The LC oscillator with temperature compensated linear wide tuning voltage range of claim 1, wherein the LC oscillator with temperature compensated linear wide tuning voltage range is implemented as a BICMOS process design flow sheet.

Description

Linear wide tuning voltage range LC oscillator with temperature compensation Technical Field The invention relates to the technical field of integrated circuits, in particular to an LC oscillator with temperature compensation and a linear wide tuning voltage range. Background With the rapid development of the technical fields of wireless communication, medical treatment, electronic countermeasure, radar and the like, a frequency source is used as a core module in the technical fields, a stable, accurate and frequency-adjustable system clock is provided, and the stable and efficient operation of the system is ensured. In a low-cost and high-integration CMOS process, how to design an on-chip integrated frequency source with high integration, low noise and low temperature drift has become a popular research direction in the industry. The frequency source designed based on the LC oscillator has the advantages of high oscillation frequency, good noise performance, good frequency stability and the like, and is widely applied to various systems. LC oscillators are mainly used in Phase Locked Loops (PLLs) in communication systems, which must remain locked during operation over a whole temperature range and cannot be re-locked after locking due to temperature drift, in which process frequency drift of the LC oscillator oscillation frequency with temperature change forms a critical problem. In order to solve the problem, a high-gain VCO can be designed, the high-gain VCO is realized by designing a curve of the variable capacitance value changing rapidly with the control voltage V CTRL, and a wide tuning range is realized by the high-gain VCO when the temperature of the system changes, so that the system can be kept locked in the whole temperature range. But the high gain VCO will degrade the PLL phase noise by up-converting the low frequency noise of the control voltage VCTRL to the carrier frequency. To optimize the phase noise and achieve that the PLL remains locked throughout the temperature range, a low VCO gain is chosen, but the gain is low, once the control voltage V CTRL exceeds the tuning range of the frequency band, the PLL will lose lock due to the temperature shift of the oscillation frequency. Disclosure of Invention The invention aims to provide an LC oscillator with temperature compensation and a linear wide tuning voltage range, so as to solve the problems in the background technology. To solve the above technical problem, the present invention provides an LC oscillator with temperature compensation and a linear wide tuning voltage range, comprising: the PMOS tubes Q1 and Q2 provide negative resistance for the LC oscillator through a cross-coupling connection mode of the PMOS tubes Q1 and Q2, and provide energy consumed by the core oscillator; The array capacitor unit selects different capacitors according to 7-bit switch control signals S witch <6:0>, changes the capacitance value of the LC oscillator during oscillation, and realizes large-range rough adjustment of oscillation frequency; The variable capacitance unit adopts a voltage linear interpolation temperature compensation technology to realize that the capacitance value of the variable capacitance unit is linearly changed within a wide control voltage V CTRL adjusting range, an LC oscillator works within a relatively wide tuning range after frequency locking is realized, a terminal voltage temperature curve of the variable capacitance is controlled, the capacitance value of the variable capacitance is reduced along with temperature rise, the influence of the fixed capacitance on the rise of the capacitance value along with the temperature rise is compensated, the change of the oscillation frequency within the whole temperature range is smaller, and continuous locking of the system within the whole temperature range is realized; Inductors L1 and L2 provide the inductance L value of the LC oscillator and act together with the total capacitance in the circuit to realize circuit oscillation; The array resistor unit selects different LOAD resistors according to 6-bit switch signals LOAD <5:0>, controls the total current of the circuit when the LC oscillator works, controls the output swing amplitude of the LC oscillator, and selects the optimal current and voltage to realize the optimization of the phase noise of the oscillator circuit. In one embodiment, the source of the PMOS transistor Q1 and the source of the PMOS transistor Q2 are connected to the power supply VDD, the gate of the PMOS transistor Q1 and the drain of the PMOS transistor Q2 are connected to the B terminal together, and the drain of the PMOS transistor Q1 and the gate of the PMOS transistor Q2 are connected to the a terminal together; The two ends of the array capacitor unit are connected to the end A and the end B, the two ends of the variable capacitor unit are connected to the end A and the end B, the two ends of the inductor L1 are connected to the end A and the end C, the tw