Independently controlled electronic oscillator with variable capabilities

Abstract

Embodiments of the present disclosure relate to independently controlled electronic oscillators with variable capabilities. The present description relates to an electronic oscillator comprising: a resonator coupled in parallel to at least one active circuit, the resonator comprising two electrodes coupled to separate variable capacitance elements, the separate variable capacitance elements forming a charge capacitance element of the electronic oscillator; and a control device configured to independently control a value of the variable capacitance element.

Description

[0001] This application claims priority to French Patent Application No. 23 / 12758, entitled "Electronic oscillator with independent controls of variable capacities", filed on November 20, 2023, which is hereby incorporated by reference in its entirety to the fullest extent permitted by law. Technical Field

[0002] The present disclosure generally relates to the field of electronic oscillators. Background Art

[0003] Electronic oscillators using quartz resonators are widely used in SoCs (systems on a chip), microcontrollers, radio devices, etc., especially in the RF (radio frequency) field. The high quality factor and low intrinsic resistance of quartz resonators enable them to maintain stable oscillations with low power consumption. The architecture commonly used for such oscillators corresponds to that of a Pierce oscillator.

[0004] For example, in some systems, such as in UWB (ultra-wideband) systems that allow precise tracking of objects, etc., it is sometimes necessary to finely adjust the oscillation frequency of such an oscillator. This adjustment of the oscillation frequency is performed by changing the value of a charge capacitance element coupled to the resonator of the oscillator. This charge capacitance element can be formed by a plurality of capacitors distributed into one or more capacitor banks. The said capacitor bank or banks can be integrated with the oscillator on a chip.

[0005] With existing oscillators, the greater the accuracy required to adjust the value of the charge capacitance element, the greater the number of capacitors in the bank. For example, when the resonator used is of the piezoelectric MEMS type, the value required for the charge capacitance element is generally lower than that of a quartz resonator. Now, the lower the value of the charge capacitance element, the greater the change in the oscillation frequency of the oscillator for a given change in the charge capacitance. This results in the adjustment accuracy of the value of the charge capacitance element having to be higher. Summary of the Invention

[0006] There is a need for an electronic oscillator that is compatible with existing quartz and MEMS technologies and in which accurate adjustment of the oscillation frequency can be easily achieved.

[0007] One embodiment overcomes all or part of the drawbacks of known solutions and provides an electronic oscillator comprising: a resonator, the resonator being coupled in parallel with at least one active circuit, the resonator comprising two electrodes, the two electrodes being coupled to different variable capacitance elements, the different variable capacitance elements forming the charge capacitance element of the electronic oscillator; and a control device, the control device being configured to independently control the values of the variable capacitance elements.

[0008] According to a specific embodiment, the control device includes a digital circuit.

[0009] According to a specific embodiment, each variable capacitance element among the variable capacitance elements includes a group of capacitors having different values.

[0010] According to a specific embodiment, each capacitor group is configured such that the value of the corresponding variable capacitance element is at least equal to the value of the first capacitor of the capacitor group.

[0011] According to a specific embodiment, each capacitor group further includes at least one second capacitor, and the at least one second capacitor is coupled to a switch, and the switch can be controlled by the control device to couple the second capacitor in parallel or not in parallel with the first capacitor of the capacitor group.

[0012] According to a specific embodiment, the group of capacitors includes capacitors having the same value from one group of capacitors to another group of capacitors.

[0013] According to a specific embodiment, the control device includes an adder configured to add the least significant bit of a control signal encoded in multiple bits to a binary number formed by bits of the control signal other than the least significant bit of the control signal, and the control device is configured to apply the output signal of the adder to at least one control input of a first capacitor group and apply the binary number to at least one control input of a second capacitor group.

[0014] According to a specific embodiment, the control device includes a look-up table (LUT), or a synthesized combinational logic circuit, or a microcontroller.

[0015] According to a specific embodiment, the resonator corresponds to a quartz resonator or a microelectromechanical system (MEMS) resonator.

[0016] According to a specific embodiment, at least one active circuit includes an inverter amplifier.

[0017] According to a specific embodiment, the inverter amplifier includes at least one metal-oxide-semiconductor (MOS) transistor.

[0018] According to a specific embodiment, the inverter amplifier further includes a feedback impedance coupled to the MOS transistor.

[0019] According to a specific embodiment, each variable capacitance element is configured such that the corresponding value is variable in a range from 2 pF to 20 pF.

[0020] There is also provided an RF transmission device including at least one electronic oscillator according to a specific embodiment.

[0021] There is also provided a control method for an electronic oscillator. The control method includes: coupling a resonator in parallel with at least one active circuit, the resonator including two electrodes that are coupled to different variable capacitance elements, and the different variable capacitance elements form a charge capacitance element of the electronic oscillator; and independently controlling the values of the variable capacitance elements by a control device.

[0022] According to a specific embodiment, the control device includes a digital circuit, each of the variable capacitance elements includes a group of capacitors having different values, the control device includes an adder configured to add the least significant bit of a control signal encoded in multiple bits to a binary number including the other bits of the control signal, and the control method includes: receiving the control signal at an input of the adder, then adding, by the adder, the least significant bit of the control signal to the binary number including the bits of the control signal other than the least significant bit of the control signal, and then applying, by the control device, the output signal of the adder to at least one control input of a first capacitor of the capacitor group and applying the binary number to at least one control input of a second capacitor of the capacitor group.

[0023] According to a specific embodiment, at least one control input of the first capacitor group and at least one control input of the second capacitor group are control inputs of controllable switches.

[0024] According to a specific embodiment, when the least significant bit of the control signal has a value of "0", the output signal of the adder is equal to the binary number including the bits of the control signal other than the least significant bit of the control signal; and when the least significant bit of the control signal has a value of "1", the output signal of the adder is equal to the sum of the "1" bit and the binary number including the bits of the control signal other than the least significant bit of the control signal.

[0025] According to a specific embodiment, when the least significant bit of the control signal has a value of "0", the values of the variable capacitance elements are the same as each other; and when the least significant bit of the control signal has a value of "1", the values of the variable capacitance elements are different from each other. Description of the Drawings

[0026] The above features and advantages, as well as other features and advantages, will be described in detail in the remainder of the specific embodiments given by way of illustration and not limitation with reference to the accompanying drawings, in which:

[0027] Figure 1 An electronic oscillator according to a specific embodiment is shown;

[0028] Figure 2 A part of the elements of an electronic oscillator according to a specific embodiment is shown;

[0029] Figure 3 and Figure 4 shows an equivalent circuit diagram of a resonator used in an electronic oscillator according to a specific embodiment;

[0030] Figure 5 shows an equivalent circuit diagram of an electronic oscillator according to a specific embodiment;

[0031] Figure 6 shows an example of the value of a charge capacitance element obtained using an electronic oscillator according to a specific embodiment; and

[0032] Figure 7 shows an RF transmission device including an electronic oscillator according to a specific embodiment. DETAILED DESCRIPTION

[0033] The same features have been designated by the same reference numerals in the various figures. Specifically, common structural and / or functional features in the various embodiments may have the same reference numerals and may be provided with the same structure, dimensions, and material properties.

[0034] For clarity, only those steps and elements that contribute to an understanding of the described embodiments are shown and described in detail. Specifically, the implementation manners of different elements and circuits (e.g., resonators, adders, controllable switches, etc.) are not described in detail. Those skilled in the art will be able to implement the different elements and different functions of the described electronic oscillator in detail based on the functional descriptions given below.

[0035] Unless otherwise specified, when referring to two elements connected together, this represents a direct connection without any intermediate elements other than conductors, and when referring to two elements coupled together, this means that the two elements can be connected, or they can be coupled via one or more other elements. In addition, in all documents, the term "coupled" must be understood to mean "electrically coupled".

[0036] In the following description, in cases where absolute position qualifiers such as "front", "rear", "top", "bottom", "left", "right", etc., or relative position qualifiers such as "top", "bottom", "upper", "lower", etc., or orientation qualifiers such as "horizontal", "vertical", etc., are referred to, unless otherwise specified, the orientation of the accompanying drawings is referred to.

[0037] Unless otherwise specified, the expressions "about", "approximate", "substantially", and "approximately" mean plus or minus 10%, preferably plus or minus 5%.

[0038] The electronic oscillator 100 according to a specific embodiment is described below in conjunction with Figure 1 is described.

[0039] The electronic oscillator 100 includes a resonator 102. The resonator 102 is, for example, a quartz resonator or a piezoelectric MEMS resonator. Such a piezoelectric MEMS resonator includes, for example, a layer of doped silicon covered with a layer of piezoelectric material (such as AlN).

[0040] The electronic oscillator 100 further includes an active circuit 104, that is, an electronic circuit or component that provides gain, and the active circuit 104 is coupled in parallel with the resonator 102. According to one embodiment, the active circuit 104 corresponds to an inverter amplifier, and the inverter amplifier includes, for example, at least one MOS transistor 106 of the N type, and at least one MOS transistor 106 is coupled to a current source 108. In Figure 1 the example, the active circuit 104 is coupled to the two electrodes 110, 112 of the resonator 102. In Figure 1 the example, the gate of the transistor 106 is coupled to the electrode 110 of the resonator 102, and the drain of the transistor 106 is coupled to the electrode 112 of the resonator 102. According to one embodiment, the transistor 106 can be a GO2 type transistor (that is, including a thick gate oxide), which exhibits good robustness against electrostatic discharge. As a variant, the transistor 106 can be of the GO1 type. As a variant, the active circuit 104 can include other types of transistors.

[0041] In the described example, the electronic oscillator 100 further includes a feedback impedance 114 coupled in parallel with the resonator 102. In Figure 1 the example, the feedback impedance 114 corresponds to a resistor.

[0042] The electronic oscillator 100 described in this example corresponds to a Pierce oscillator. As a variant, the electronic oscillator 100 can be different from a Pierce oscillator.

[0043] The electrodes 110, 112 of the resonator 102 are coupled to different variable capacitance elements 116, 118, and the different variable capacitance elements 116, 118 form the charge capacitance elements of the electronic oscillator 100. According to a specific embodiment, each of the variable capacitance elements 116, 118 includes a group of capacitors, and the group of capacitors can have values different from each other or can not have values different from each other.

[0044] In Figure 1In the example, each capacitor bank of variable capacitance elements 116 and 118 includes first capacitors 120 and 122, which have values corresponding to the minimum values of each of the variable capacitance elements in variable capacitance elements 116 and 118. In the illustrated example, the first capacitors 120 and 122 of each of the variable capacitance elements in variable capacitance elements 116 and 118 are always coupled to resonator 102. In other words, during the operation of electronic oscillator 100, the coupling between the first capacitors 120 and 122 of each of the variable capacitance elements in variable capacitance elements 116 and 118 and resonator 102 is not interrupted. In this embodiment, the value of each of the first capacitors 120 and 122 is referred to as "Cfixed".

[0045] In Figure 1 the example, one of the two electrodes of each of the first capacitors 120 and 122 is coupled to one of the electrodes 110 and 112 of resonator 102, and the other of the two electrodes of each of the first capacitors 120 and 122 is coupled to the reference potential of electronic oscillator 100, for example, the ground of electronic oscillator 100.

[0046] In the example of the described embodiment, each capacitor bank of variable capacitance elements 116 and 118 further includes at least one second capacitor coupled to a controllable switch, and the controllable switch itself is coupled to one of the electrodes 110 and 112 of resonator 102. In the example of the embodiment described herein, each capacitor bank of variable capacitance elements 116 and 118 includes a plurality of other capacitors, each of which is coupled to a switch that can be controlled independently of the other capacitors and is coupled to one of the electrodes 110 and 112 of resonator 102. In Figure 1 the example, each capacitor bank of variable capacitance elements 116 and 118 includes a second capacitor, a third capacitor, and a fourth capacitor, which are designated by reference numerals 124, 128, and 132 for variable capacitance element 116, respectively, and by reference numerals 126, 130, and 134 for variable capacitance element 118, respectively. In Figure 1In the example, each of the capacitors 124 to 134 includes a first electrode coupled to a reference potential and a second electrode coupled to a controllable switch, and the controllable switches are designated by reference numerals 136, 138, 140, 142, 144, and 146 respectively. Thus, in each capacitor bank of the capacitor banks of the capacitive elements 116, 118, each of the capacitors 124 to 134 can be coupled in parallel with the first capacitors 120, 122 according to the off or on state of the controllable switches 136 to 146 coupled to each of these capacitors 124 to 134.

[0047] In the example of the illustrated embodiment, the capacitors of the groups of the variable capacitive elements 116, 118 have the same value from one group to another. In Figure 1 the example, the values of the second, third, and fourth capacitors 124 to 134 are equal to C, C / 2, and C / 4 respectively. Thus, in this example, each of the variable capacitive elements 116, 118 can take one of the following values according to the states of the controllable switches 136 to 146: Cfixed, Cfixed + C / 4, Cfixed + C / 2, Cfixed + 3C / 4, Cfixed + C, Cfixed + 5C / 4, Cfixed + 3C / 2, Cfixed + 7C / 4.

[0048] The values C and Cfixed can be selected here according to the required values of the charge capacitive elements of the electronic oscillator 100. According to the example of the embodiment, the values C and Cfixed can be selected such that the values of the variable capacitive elements 116, 118 can vary in the range of 2 pF to 20 pF, which enables the charge capacitance of the oscillator 100 to be changed using values in the range from 1 pF to 10 pF.

[0049] The electronic oscillator 100 further includes a control device 148 configured to independently control the values of the variable capacitive elements 116, 118, that is, such that the values of the variable capacitive elements 116, 118 can be similar or different from each other. In the example of the described embodiment, the control device 148 is configured to send control signals to the controllable switches 136 to 146 of each of the variable capacitors of the variable capacitive elements 116, 118.

[0050] In the example of the described embodiment, the control device 148 includes or corresponds to a digital circuit. In Figure 1In the example, the control device 148 is configured to transmit a first control signal encoded on multiple bits to control switches 136, 140, 144 of the capacitor bank of the first variable capacitance element 116, and transmit a second control signal encoded on multiple bits to control switches 138, 142, 146 of the capacitor bank of the second variable capacitance element 118.

[0051] Since the variable capacitance elements 116, 118 are controlled independently of each other, when the values of the variable capacitance elements 116, 118 are intended to be similar, the values of the first control signal and the second control signal transmitted by the control device 148 can be similar, or when the values of the variable capacitance elements 116, 118 are intended to be different from each other, the values of the first control signal and the second control signal transmitted by the control device 148 can be different.

[0052] Another example of an embodiment of the variable capacitance elements 116, 118 and the control device 148 is shown in Figure 2 is shown.

[0053] In this another example, each of the variable capacitance elements 116, 118 includes a group of capacitors, the group of capacitors includes first capacitors 120, 122 with a value of "Cfixed", and second, third, fourth capacitors 124 to 134 and fifth capacitors 133, 135 having values equal to C, 2C, 4C, and 8C respectively in this another example. In Figure 2 In the example, each of the capacitors 124 to 135 includes a first electrode electrically coupled to the electrical reference potential of the electronic oscillator 100 and a second electrode coupled to the controllable switches 136 to 147 (the fifth capacitors 133, 135 are coupled to the controllable switches 145, 147). Thus, in this example, according to the states of the controllable switches 136 to 147, each variable capacitance in the variable capacitances 116, 118 can take a value in the range from Cfixed to Cfixed + 15C, where the intermediate values are equal to Cfixed + a*C, and a is an integer in the range from 1 to 14. The values C and Cfixed are selected, for example, such that the values of the variable capacitance elements 116, 118 can vary in the range from 2 pf to 20 pF.

[0054] In this another example, the control device 148 includes an adder 150, and the adder 150 is configured to receive an initial control signal encoded on multiple bits as an input (one input for each bit of the initial control signal). In the example of the described embodiment, the number of bits of the initial control signal is equal to the number of capacitors in each capacitor bank of the variable capacitance elements 116, 118 (i.e., Figure 25) in the example. In this example, the adder 150 is configured to add the least significant bit of the initial control signal to the binary number formed by the other bits of the initial control signal. Additionally, in the described example, the control device 148 is configured to apply the output signal of the adder 150 to at least one control input of the first variable capacitor 116 (in the described example, one control input for each bit) to control the controllable switch of the first variable capacitance element 116. In this example, the binary number formed by the bits of the initial control signal other than the least significant bit is applied to at least one control input of the second variable capacitance element 118 (in the described example, one control input for each bit) to control the controllable switch of the second variable capacitance element 118. In the described example, the number of bits of the signal sent to the inputs of the variable capacitance elements 116, 118 is equal to the number of controllable switches of each capacitor bank in the capacitor banks of the variable capacitance elements 116, 118.

[0055] Thus, in Figure 2 the example, the adder 150 is configured to perform the addition C = A + B, where B corresponds to the least significant bit of the initial control signal, A corresponds to the binary number formed by the bits at the input of the adder 150 (which also corresponds to the control signal sent to the second variable capacitance element 118), and C corresponds to the binary number obtained at the output of the adder 150 (which forms the control signal sent to the first variable capacitance element 116). In Figure 2 the example, the least significant bit of the initial control signal is applied to the input "B0" of the adder 150, the other bits of the initial control signal are applied to the inputs "A0", "A1", "A2", and "A3" of the adder 150, and the output signal of the adder 150 is passed to the outputs "C0", "C1", "C2", and "C3" of the adder 150.

[0056] Thus, in Figure 2In the configuration shown, when the least significant bit of the initial control signal applied to adder 150 has a value of "0", the binary number propagated at the output of adder 150 is equal to the binary number formed by the other bits of the initial control signal applied to the input of adder 150. In this case, the control signals applied to the controllable switches of the capacitor banks of variable capacitor elements 116, 118 are the same, which results in variable capacitor elements 116, 118 having the same value. When the bit of the initial control signal applied to input B of adder 150 has a value of "1", the binary number propagated at bit C is equal to the sum of bit "1" and the binary number formed by the other bits of the initial control signal received by adder 150. In this case, the control signals applied to the controllable switches of the capacitor banks of variable capacitor elements 116, 118 are different and variable capacitor elements 116, 118 have different values such that C116 = C118 + C, where C116 and C118 correspond to the values of variable capacitor elements 116 and 118 respectively. To avoid problems in the case of exceeding the capacitance of adder 150 (the "overflow" situation that occurs when all bits applied at the input are set to "1"), the control device 148 can include an OR gate at the output of adder 150 to set the output of control device 148 to state "1" in such a case.

[0057] The operation of electronic oscillator 100 will be described in further detail hereinafter.

[0058] Figure 3 An equivalent circuit diagram of resonator 102 is shown, which is applicable to quartz or piezoelectric MEMS resonator 102. Resonator 102 can be electrically modeled by resistor 152, which corresponds to the equivalent series resistance of resonator 102. Resistor 152 is serially electrically coupled between the first electrode 110 of resonator 102 and inductor 154, which in turn is electrically coupled to the first electrode of first capacitor element 156. Resistor 152 represents the mechanical losses of resonator 102, and its value is proportional to the quality factor of resonator 102 (lower in the case of piezoelectric MEMS type resonators than quartz resonators). Inductor 154 represents the elasticity of resonator 102, and first capacitor element 156 represents the mechanical inertia of resonator 102. The second electrode of first capacitor element 156 is coupled to the second electrode 112 of resonator 102. Second capacitor 158 is parallely electrically coupled to the assembly formed by resistor 152, inductor 154 and first capacitor element 156. Second capacitor element 158 represents the parasitic capacitance of resonator 102 (in the case of piezoelectric MEMS type resonator 102, it is associated with the thickness of the piezoelectric film and its dielectric constant).

[0059] Figure 4shows an equivalent circuit diagram of resonator 102 when it receives opposite signals or signals with opposite phases on its electrodes 110, 112. In this case, the second capacitance element 158 previously described in conjunction with Figure 3 can be regarded as forming two different capacitance elements, which are represented by reference numerals 160 and 162. Each capacitance element includes an electrode coupled to a reference potential (e.g., the ground or virtual ground corresponding to resonator 102). The value of each of the two capacitance elements 160, 162 is equal to twice the value of capacitance element 158.

[0060] Figure 5 shows an equivalent circuit diagram of electronic oscillator 100. In this circuit diagram, in addition to the elements of resonator 102 previously described in conjunction with Figure 4 the active circuit 104 can be electrically modeled by a negative resistor 164. For example, the negative resistor 164 has a value equal to -Gm / ((2C0 + C116)·(2C0 + C118)·2π·f)², where Gm corresponds to the transconductance of transistor 106 (having a value proportional to the consumed bias current), and f corresponds to the oscillation frequency of resonator 102. The oscillation frequency f of electronic oscillator 100 osc is equal to:

[0061] Mathematical formula 1

[0062]

[0063] where Lm is equal to the value of inductor 154, and Ceq is equal to the value of the equivalent capacitance element formed by various capacitance elements in the Figure 5 circuit diagram, and it satisfies:

[0064] Mathematical formula 2

[0065]

[0066] where Cm corresponds to the value of the first capacitance element 156, and C0 corresponds to the value of the second capacitance element 158.

[0067] When the sum of the value of resistor 152 and the value of 164 is zero, electronic oscillator 100 is in a stable oscillation state. Since the values of Lm, Cm, and CO cannot be modified, the oscillation frequency f of electronic oscillator 100 osc is set by setting the values of the variable capacitance elements 116, 118, which is equivalent to modifying the value of Ceq, and thus modifying f oscValue. Considering the equivalent circuit diagram of the electronic oscillator 100, the larger the value of the equivalent series resistor 152, the larger the value of the negative resistor 164 must be to compensate for the resistor 152, which results in a higher transconductance Gm (and thus more current provided by the transistor 106) or a lower ratio (2C0 + C116) / (2C0 + C118) obtained by adjusting the values of C116 and C118 (the value of C0 is not adjustable because it depends on the physical characteristics of the resonator 102).

[0068] Therefore, in order to adjust the oscillation frequency of the electronic oscillator 100 to compensate for possible variations (usually + / - 10 ppm) of the resonator 102, the values of the variable capacitance elements 116, 118 are selected by applying a desired control signal at the inputs of these capacitance elements, and the obtained value of the charge capacitance element CL is such that CL = (C116 + C118) / 2. Thus, considering that the value of each variable capacitance element in the variable capacitance elements 116, 118 can be adjusted with a spacing equal to 1 pF, the independent control of the values of the variable capacitance elements enables the value of CL to be adjusted with a spacing equal to 0.25 pF.

[0069] Figure 6 Shows the value of the charge capacitance element CL obtained using variable charge capacitance elements 116, 118 such as those previously described Figure 2 described, where Cfixed = 4 pF and C = 1 pF. The x-axis represents the value of the binary word applied at the input of the adder 150 and applied to the control input of the second variable charge capacitance element 118. The obtained values of the charge capacitance element CL form a monotonic straight line that is very suitable for the fine control of the oscillation frequency of the electronic oscillator 100. In Figure 6 the example of, using a 4-bit control signal, 31 different values of the charge capacitance element CL are possible.

[0070] When the resonator 102 is of the MEMS type, all components of the oscillator 100 can be formed within the same chip of, for example, the SoC type.

[0071] The electronic oscillator 100 provides a solution that enables the adjustment resolution of increasing the oscillation frequency of the oscillator to be adjusted via an adjustment independent of the value of each variable capacitance element forming the charge capacitance element of the electronic oscillator.

[0072] The advantage of the electronic oscillator 100 described above is that the resonator 102 and / or the active circuit 104 and / or the variable capacitors 116, 118 can correspond to existing elements to which the control device 148 is added. For example, the advantage of using the digital control device 148 is that its addition is simpler than modifying or adding analog elements (such as adding capacitors to the capacitor banks of the variable capacitance elements 116, 118).

[0073] In a specific configuration, the electronic oscillator 100 can have the advantages provided by using a Pierce-type oscillator structure, namely, specifically, low current consumption, low noise, possible high-frequency operation, and good robustness against electrostatic discharge.

[0074] The electronic oscillator 100 enables the monotonic characteristic of the value of the charge capacitance element to be obtained without complicating its layout or design, and at the same time, compared with existing solutions, uses a smaller number of capacitors or does not increase the number of capacitors used.

[0075] The electronic oscillator 100 can be applied to the RF field, and particularly to the RF SoC field, or the field of transceivers and / or the field of UWB / NB (narrowband) Internet of Things (IoT) devices. Figure 7 An example of an RF transmission device 1000 is shown. The RF transmission device 1000 corresponds to a UWB transceiver in this example, and the UWB transceiver includes an electronic oscillator 100 such as previously described.

[0076] In the above example, the electronic oscillator 100 is of the Pierce type. As a variant, the oscillator 100 can correspond to another type of oscillator. In addition, the active circuit 104 can be different from the previously described circuit.

[0077] The number of capacitors forming the variable capacitance element and thus the number of bits used to control the value of the variable capacitance element can be different from the number in the previously described example.

[0078] A control device 148 different from the previously described control device (i.e., including one or more electronic components or circuits other than an adder) can be used to implement the same function as the function implemented by the previously described example of the control device 148. For example, the control device can include a LUT (look-up table), or a synthesized combinational logic circuit, or a microcontroller.

[0079] Various embodiments and variants have been described. Those skilled in the art will understand that certain features of these various embodiments and variants can be combined, and those skilled in the art will think of other variants.

[0080] Finally, the actual implementation of the described embodiments and variants is within the capabilities of those skilled in the art based on the functional indications given above.

[0081] An electronic oscillator (100) can be generally described as including: a resonator (102) coupled in parallel with at least one active circuit (104), the resonator (102) including two electrodes (110, 112), the two electrodes (110, 112) being coupled to different variable capacitance elements (116, 118), the different variable capacitance elements (116, 118) forming the charge capacitance elements of the electronic oscillator (100); and a control device (148), the control device (148) being configured to independently control the values of the variable capacitance elements (116, 118).

[0082] The control device (148) can include a digital circuit.

[0083] Each of the variable capacitance elements (116, 118) can include a set of capacitors (120 - 135) having different values.

[0084] Each capacitor set (120 - 135) can be configured such that the value of the corresponding variable capacitance element (116, 118) is at least equal to the value of the first capacitor (120, 122) of the capacitor set (120 - 135).

[0085] Each capacitor set (120 - 135) can further include at least one second capacitor (124 - 135), the at least one second capacitor (124 - 135) being coupled to a controllable switch (136 - 147) by the control device (148) to couple the second capacitor (124 - 135) in parallel with or not in parallel with the first capacitor (120, 122) of the capacitor set (120 - 135).

[0086] The sets of capacitors (120 - 135) of the variable capacitance elements (116, 118) can include capacitors (120 - 135) having the same value from one set of the capacitors (120 - 135) to another set of the capacitors (120 - 135).

[0087] Each variable capacitance element in the variable capacitance elements (116, 118) may include a group of capacitors (120 - 135) having different values, and the control device (148) may include an adder (150) configured to add the least significant bit of a control signal encoded on a plurality of bits to a binary number formed by bits of the control signal other than the least significant bit of the control signal, and the control device (148) may be configured to apply the output signal of the adder (150) to at least one control input of a first capacitor group among the groups of capacitors (120, 124, 128, 132, 133), and apply the binary number to at least one control input of a second capacitor group among the groups of capacitors (120, 124, 128, 132, 133).

[0088] The control device (148) may include a look-up table (LUT), or a synthesized combinational logic circuit, or a microcontroller.

[0089] The resonator (102) may correspond to a quartz resonator or a microelectromechanical system (MEMS) resonator.

[0090] At least one active circuit (104) may include an inverter amplifier.

[0091] The inverter amplifier may include at least one metal oxide semiconductor (MOS) transistor (106).

[0092] The inverter amplifier may further include a feedback impedance (114) coupled to the MOS transistor (106).

[0093] The variable capacitance elements (116, 118) may each be configured such that the corresponding value is variable in the range of 2 pF to 20 pF.

[0094] A radio frequency (RF) transmission device (1000) may be generally described as including at least one electronic oscillator (100), the at least one electronic oscillator (100) including: a resonator coupled in parallel with at least one active circuit, the resonator including two electrodes coupled to different variable capacitance elements, the different variable capacitance elements forming a charge capacitance element of the electronic oscillator; and a control device configured to independently control the values of the variable capacitance elements.

[0095] A control method for an electronic oscillator (100) can be generally summarized as including: coupling a resonator (102) in parallel with at least one active circuit (104), the resonator (102) including two electrodes (110, 112), the two electrodes (110, 112) being coupled to different variable capacitance elements (116, 118), the different variable capacitance elements (116, 118) forming charge capacitance elements of the electronic oscillator (100); and independently controlling the values of the variable capacitance elements (116, 118) by a control device (148).

[0096] The control device (148) can include a digital circuit, and each of the variable capacitance elements (116, 118) can include a set (120 - 135) of capacitors having different values, and the control device (148) can include an adder (150), the adder (150) being configured to add the least significant bit of a control signal encoded on multiple bits to a binary number, the binary number including bits of the control signal other than the least significant bit of the control signal, and the control method can include: receiving the control signal at an input of the adder (150), then adding, by the adder (150), the least significant bit of the control signal to the binary number including bits of the control signal other than the least significant bit of the control signal, and then applying, by the control device (148), the output signal of the adder (150) to at least one control input of a first set (120, 124, 128, 132, 133) of capacitors and applying the binary number to at least one control input of a second set (122, 126, 130, 134, 135) of capacitors.

[0097] At least one control input of the first set (120, 124, 128, 132, 133) of capacitors and at least one control input of the second set of capacitors can be control inputs of controllable switches (136 - 147).

[0098] When the least significant bit of the control signal has a "0" value, the output signal of the adder (150) can be equal to the binary number including bits of the control signal other than the least significant bit of the control signal; and when the least significant bit of the control signal has a "1" value, the output signal of the adder (150) can be equal to the sum of the "1" bit and the binary number including bits of the control signal other than the least significant bit of the control signal.

[0099] When the least significant bit of the control signal has a "0" value, the values of the variable capacitance elements (116, 118) can be the same as each other; and when the least significant bit of the control signal has a "1" value, the values of the variable capacitance elements (116, 118) can be different from each other.

[0100] The various embodiments described above can be combined to provide additional embodiments. All U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications, and non-patent publications mentioned in this specification and / or listed in the application data sheet are hereby incorporated by reference in their entirety. Aspects of the embodiments can be modified as needed to incorporate the concepts of various patents, applications, and publications to provide additional embodiments.

[0101] These and other changes may be made to the embodiments in light of the above detailed description. In general, in the following claims, the terms used should not be construed as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments and the full scope of equivalents to such claims. Thus, the claims are not limited by the present disclosure.

Claims

1. An electronic oscillator, comprising: a resonator coupled in parallel with at least one active circuit, the resonator comprising two electrodes coupled to different variable capacitance elements, different variable capacitance elements forming charge capacitance elements of the electronic oscillator; as well as A control device is configured to independently control the value of the variable capacitance element.

2. An electronic oscillator according to claim 1, wherein the control device comprises a digital circuit.

3. The electronic oscillator of claim 1, wherein each of the variable capacitance elements comprises a group of capacitors, the groups of capacitors having different values.

4. An electronic oscillator according to claim 3, wherein each capacitor bank is configured such that a value of a corresponding variable capacitance element is at least equal to a value of a first capacitor of the capacitor bank.

5. The electronic oscillator according to claim 4, wherein each capacitor group further comprises at least one second capacitor, and the at least one second capacitor is coupled to a controllable switch by the control device to couple the second capacitor in parallel or not in parallel with the first capacitor of the capacitor group.

6. The electronic oscillator of claim 3, wherein the groups of capacitors include capacitors having the same value from one group of capacitors to another group of capacitors.

7. An electronic oscillator according to claim 2, wherein each of the variable capacitive elements comprises a group of capacitors, the groups of capacitors having different values, and wherein the control device comprises an adder, the adder being configured to add the least significant bit of the control signal encoded on a plurality of bits to a binary number formed by the bits of the control signal other than the least significant bit of the control signal, and wherein the control device is configured to apply the output signal of the adder to at least one control input of a first group of capacitors and to apply the binary number to at least one control input of a second group of capacitors.

8. The electronic oscillator according to claim 1, wherein the control device comprises a lookup table (LUT), or a synthesized combinational logic circuit, or a microcontroller.

9. The electronic oscillator according to claim 1, wherein the resonator corresponds to a quartz resonator or a micro-electromechanical system (MEMS) resonator.

10. The electronic oscillator of claim 1, wherein the at least one active circuit comprises an inverter amplifier.

11. The electronic oscillator of claim 10, wherein the inverter amplifier comprises at least one metal oxide semiconductor (MOS) transistor.

12. The electronic oscillator of claim 11, wherein the inverter amplifier further comprises a feedback impedance coupled to the MOS transistor. 13 . The electronic oscillator according to claim 1 , wherein the variable capacitance elements are each configured so that a corresponding value can be varied within a range from 2 pF to 20 pF.

14. A radio frequency (RF) transmission device comprising at least one electronic oscillator according to claim 1.

15. A method for controlling an electronic oscillator, comprising: coupling a resonator in parallel with at least one active circuit, the resonator comprising two electrodes coupled to different variable capacitance elements, different variable capacitance elements forming charge capacitance elements of the electronic oscillator, and The values ​​of the variable capacitance elements are independently controlled by a control device.

16. The control method according to claim 15, wherein: The control device comprises a digital circuit, Each of the variable capacitive elements comprises a group of capacitors, the groups of capacitors having different values, and The control device includes an adder configured to add a least significant bit of a control signal encoded on a plurality of bits to a binary number including bits of the control signal other than the least significant bit of the control signal, and The control method comprises: The control signal is received at the input of the adder, and then The adder adds the least significant bit of the control signal to the binary number including the bits of the control signal excluding the least significant bit of the control signal, and then applying the output signal of the adder to at least one control input of a first group of capacitors via the control device, and The binary number is applied to at least one control input of a second set of capacitors.

17. The control method of claim 16, wherein the at least one control input of the first group of capacitors and the at least one control input of the second group of capacitors are control inputs of controllable switches.

18. The control method according to claim 16, wherein: When the least significant bit of the control signal has a value of "0", the output signal of the adder is equal to the binary number including the bits of the control signal except the least significant bit of the control signal; and When the least significant bit of the control signal has a “1” value, the output signal of the adder is equal to the sum of the “1” bit and the binary number including the bits of the control signal excluding the least significant bit of the control signal.

19. The control method according to claim 18, wherein: When the least significant bit of the control signal has the value of "0", the values ​​of the variable capacitance elements are identical to each other; and When the least significant bit of the control signal has the “1” value, the values ​​of the variable capacitance elements are different from each other.

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