阅读说明：本技术 一种用于射频收发系统的抑制温漂的无晶振压控振荡器 (Crystal-free voltage-controlled oscillator for restraining temperature drift of radio frequency transceiving system ) 是由 邓金鸣 邸庆祥 于 2019-10-10 设计创作，主要内容包括：本发明公开了一种用于射频收发系统的抑制温漂的无晶振压控振荡器,涉及集成电路领域,所述无晶振压控振荡器被设置于差分LC震荡电路中,所述差分LC震荡电路中包括VDD端和GND端,在所述VDD端与所述GND端之间还设有VCO和电容阵列。本发明提供的无晶振压控振荡器不需要外部晶振,且内部只需要DAC+VCO就可以实现发射频率的调制,结构简单,功耗低。另外,本发明采用温度补偿电容阵列,解决了电容容值随温度变化的问题。(The invention discloses a crystal-free voltage-controlled oscillator for inhibiting temperature drift of a radio frequency transceiving system, and relates to the field of integrated circuits. The crystal-free voltage-controlled oscillator provided by the invention does not need an external crystal oscillator, can realize the modulation of the transmitting frequency only by DAC + VCO, and has simple structure and low power consumption. In addition, the invention adopts the temperature compensation capacitor array, thus solving the problem that the capacitance value of the capacitor changes along with the temperature.)

1. The crystal-free voltage-controlled oscillator is characterized in that the crystal-free voltage-controlled oscillator is arranged in a differential LC oscillating circuit, the differential LC oscillating circuit comprises a VDD end and a GND end, and a VCO and a capacitor array are further arranged between the VDD end and the GND end.

2. The crystal-less voltage-controlled oscillator for suppressing temperature drift of a radio frequency transceiver system as claimed in claim 1, wherein the oscillation frequency of the differential LC oscillator circuit is:

3. the crystal-less VCO capable of suppressing temperature drift for RF transceiver system as claimed in claim 2, wherein said capacitor array employs a variable capacitor, and the capacitance of said variable capacitor increases with temperature, and without temperature compensation, the oscillation frequency becomes lower.

4. The crystal-less voltage-controlled oscillator with temperature drift suppression for radio frequency transceiving system of claim 3, wherein said capacitor array comprises a frequency adjusting capacitor array, a temperature drift suppression capacitor array and a modulation capacitor array.

5. The crystal-less voltage-controlled oscillator with temperature drift suppression for radio frequency transceiving system of claim 4, wherein the frequency adjusting capacitor array comprises one or more units, each of the units comprising OSCN, OSCP and digital signal D, 0 indicating the capacitor path is closed, 1 indicating the capacitor path is closed; the frequency adjustment capacitor array is composed of capacitors with large capacitance values.

6. The crystal-less VCO for RF transceiver system as in claim 4, wherein said array of temperature drift suppression capacitors has a capacitor voltage from VDD via a diode V_BEAnd (4) generating.

7. The crystal-less VCO for RF transceiver systems as in claim 6, wherein said diode V is comprised of a diode having a diode voltage level_BEAnd temperature as follows:

8. the crystal-less voltage-controlled oscillator with temperature drift suppression for radio frequency transceiving system according to claim 4, wherein said modulating capacitor array is composed of capacitors with smaller capacitance values.

9. The crystal-less voltage-controlled oscillator for suppressing temperature drift of radio frequency transceiver system as claimed in claim 8, wherein the analog voltage outputted from the DAC is directly applied to the capacitor, and different DAC inputs correspond to small changes in frequency to realize modulation of baseband signals on the carrier signal.

10. The crystal-less voltage-controlled oscillator for suppressing the temperature drift of radio frequency transceiver system as claimed in claim 9, wherein the number of the access capacitors is adjusted from K <0> to K <2>, thereby adjusting the frequency variation speed.

Technical Field

The invention relates to the field of integrated circuits, in particular to a voltage-controlled oscillator circuit which can be applied to a crystal-oscillator-free radio frequency transceiving system, and particularly relates to a crystal-oscillator-free voltage-controlled oscillator for inhibiting temperature drift of the radio frequency transceiving system.

Background

The existing wireless transceiving system usually adopts a phase-locked loop system with a crystal oscillator, but needs an external crystal oscillator, has high cost, needs a phase frequency detector, a charge pump, a decimal frequency division and the like to form a closed-loop feedback system, and has a complex structure and larger power consumption.

In the single VCO system, as the temperature of the chip gradually increases with the lapse of time, the capacitance value of the capacitor shifts in frequency with the change in temperature, and thus the single VCO circuit cannot be used in the radio frequency transceiver system due to temperature drift, unstable frequency, and the like.

Accordingly, those skilled in the art have been made to develop a new voltage controlled oscillator circuit that overcomes the above-mentioned problems of the prior art.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, the technical problem to be solved by the present invention is how to realize modulation of the transmission frequency without an external crystal oscillator and solve the problem of capacitance variation with temperature.

In order to achieve the above object, the present invention provides a crystal-less voltage-controlled oscillator for suppressing temperature drift in a radio frequency transceiver system, wherein the crystal-less voltage-controlled oscillator is disposed in a differential LC oscillator circuit, the differential LC oscillator circuit includes a VDD terminal and a GND terminal, and a VCO and a capacitor array are further disposed between the VDD terminal and the GND terminal.

Further, the oscillation frequency of the differential LC oscillating circuit is:

further, the capacitor used by the capacitor array is a variable capacitor, the capacitance value of the variable capacitor increases with the increase of temperature, and the oscillation frequency becomes lower without temperature compensation.

Further, the capacitor array comprises a frequency adjusting capacitor array, a temperature drift suppression capacitor array and a modulation capacitor array.

Further, the frequency adjustment capacitor array comprises one or more units, each unit comprises an OSCN, an OSCP and a digital signal D, 0 represents that the capacitor path is closed, and 1 represents that the capacitor path is closed; the frequency adjustment capacitor array is composed of capacitors with large capacitance values.

Further, the voltage of the capacitor in the temperature drift suppression capacitor array is from the VDD end through a diode V_BEAnd (4) generating.

Further, the diode V_BEAnd temperature as follows:

further, the modulation capacitor array is composed of capacitors with smaller capacitance values.

Furthermore, analog voltage output by the DAC is directly applied to the capacitor, and different DAC inputs correspond to tiny changes of frequency, so that modulation of the baseband signal on the carrier signal is achieved.

Further, the number of the access capacitors is adjusted from K <0> to K <2>, so that the speed of frequency change is adjusted.

The crystal-free voltage-controlled oscillator for restraining the temperature drift of the radio frequency transceiving system does not need an external crystal oscillator, can realize the modulation of the transmitting frequency only by using DAC + VCO inside, and has simple structure and low power consumption.

In addition, the invention adopts the temperature compensation capacitor array, thus solving the problem that the capacitance value of the capacitor changes along with the temperature.

The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.

Drawings

Fig. 1 is a circuit configuration of a VCO according to a preferred embodiment of the present invention;

FIG. 2 is a frequency tuning capacitor array in accordance with a preferred embodiment of the present invention;

FIG. 3 is a schematic diagram of a temperature drift suppression capacitor array according to a preferred embodiment of the present invention;

FIG. 4 is a modulated capacitor array according to a preferred embodiment of the present invention.

Detailed Description

The technical contents of the preferred embodiments of the present invention will be more clearly and easily understood by referring to the drawings attached to the specification. The present invention may be embodied in many different forms of embodiments and the scope of the invention is not limited to the embodiments set forth herein.

In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views. The size and thickness of each component shown in the drawings are arbitrarily illustrated, and the present invention is not limited to the size and thickness of each component. The thickness of the components may be exaggerated where appropriate in the figures to improve clarity.

Fig. 1 is a schematic diagram of a VCO circuit.

In fig. 1, the crystal-less voltage-controlled oscillator is disposed in a differential LC oscillator circuit, which includes a VDD terminal and a GND terminal, and a VCO and a capacitor array are disposed between the VDD terminal and the GND terminal.

Wherein, the oscillation frequency of the differential LC oscillating circuit is:

the capacitance of the capacitor array is a variable capacitor, the capacitance value of the variable capacitor increases with the temperature, and if temperature compensation is not performed, the oscillation frequency becomes low.

The capacitor array comprises a frequency adjusting capacitor array, a temperature drift suppression capacitor array and a modulation capacitor array.

Wherein the frequency tuning capacitor array (as shown in fig. 2) comprises one or more units, each unit comprises an OSCN, an OSCP and a digital signal D, 0 indicates that the capacitor path is closed, and 1 indicates that the capacitor path is closed; the frequency adjusting capacitor array is composed of capacitors with large capacitance values. The frequency adjusting capacitor array performs coarse adjustment on the frequency, and the frequency is controlled within an approximate range.

Wherein, the voltage of the capacitor in the temperature drift suppression capacitor array (as shown in FIG. 3) is from the VDD terminal via a diode V_BEAnd (4) generating.

Wherein, the diode V_BEAnd temperature as follows:

when V is_BE＝750mV，m＝-1.5，The value of the above expression is-1.5 mV/K, which is a negative temperature coefficient. With the increase of the temperature, Vctrl is increased, the voltage between two ends of the capacitor is reduced, the capacitance value of the capacitor is reduced, and the negative effect brought by the temperature is compensated.

Wherein, the modulation capacitor array (as shown in fig. 4) is composed of capacitors with smaller capacitance values.

Analog voltage output by the DAC is directly applied to the capacitor, and different DAC inputs correspond to small frequency changes, so that modulation of baseband signals on carrier signals is achieved.

The number of the access capacitors is adjusted from K <0> to K <2>, so that the speed of frequency change is adjusted.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.