Oscillation circuit
By introducing programmable capacitor arrays and feedback networks into the oscillation circuits, the problems of narrow application range and poor control accuracy of traditional oscillation circuits are solved, and high-precision frequency calibration and widely applicable oscillation circuits are realized.
Patent Information
- Application Number
- CN202422193043.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-06
- Publication Date
- 2025-06-27
- Estimated Expiration
- 2034-09-06
AI Technical Summary
In the prior art, the traditional crystal inverter oscillation circuit has a narrow range of application and poor control accuracy, making it difficult to provide an oscillation circuit with a wide range of application and high accuracy.
An oscillation circuit including a resonator, a programmable capacitor array and a feedback network is designed. Frequency calibration is performed through a programmable capacitor array and feedback negative resistance is adjusted through a feedback network to meet the needs of different resonators.
It realizes high-precision frequency calibration and wide applicability of the oscillation circuit, and can be adapted to traditional quartz crystal oscillation circuits and other types of resonators, such as MEMS, FBAR, BAW, SAW, etc.
Smart Images
Figure CN223039991U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of oscillators, in particular to an oscillation circuit with high-precision frequency calibration and feedback negative resistance adjustment. Background Art
[0002] A resonator is an electronic component that generates a resonant frequency. Commonly used resonators are divided into quartz crystal resonators and ceramic resonators, which have the characteristics of stability and good anti-interference performance and are widely used in various electronic products. The frequency accuracy of a quartz crystal resonator is higher than that of a ceramic resonator, but the cost is also higher than that of a ceramic resonator. Resonators mainly play a role in frequency control, and all electronic products involving frequency transmission and reception require resonators. The types of resonators can be divided into through-hole and surface mount according to their shapes. In the prior art, the applicable range of a traditional crystal inverter oscillation circuit is narrow and the control accuracy is poor. Summary of the Utility Model
[0003] The technical problem to be solved by the utility model is how to provide an oscillation circuit with a wide applicable range and high precision.
[0004] To solve the above technical problem, the technical solution adopted by the utility model is: an oscillation circuit, including a resonator, two signal connection ends of the resonator are respectively connected to node B and node C, a programmable capacitor array is connected between node B and node C and the resonator, one end of a feedback network is connected to node B, the other end of the feedback network is connected to node C, node B is connected to node A through resistor R1, an oscillation amplification circuit is arranged between node A and node C, and a control signal is output after node A passes through amplifier A1 and amplifier A2 in sequence.
[0005] A further technical solution lies in that: the feedback network includes a plurality of PMOS transistors and a plurality of NMOS transistors. The drain of PMOS transistor P<0> is connected to the drain of NMOS transistor N<0> and then connected to node B. The source of PMOS transistor P<0> is connected to the source of NMOS transistor N<0> and then connected to the drain of PMOS transistor P<1> and the drain of NMOS transistor N<1>. The source of PMOS transistor P<1> and the source of NMOS transistor N<1> are connected and then connected to the drain of PMOS transistor P<2> and the drain of NMOS transistor N<2>, and so on. The source of PMOS transistor P <n-2>the source electrode and NMOS transistor N <n-2>After the source electrode is connected, it is connected to PMOS transistor P <n-1>the drain of and NMOS transistor N <n-1>The drain connection of PMOS transistor P <n-1>the source of and NMOS transistor N <n-1>After the source electrode is connected, it is connected to the node C. The gates of the PMOS transistor and the NMOS transistor are control signal input terminals, and n is a natural number greater than or equal to 1.
[0006] A further technical solution lies in that: the programmable capacitor array includes a first programmable capacitor sub-array connected to the node B and a second programmable capacitor sub-array connected to the node C. The structures of the first programmable capacitor sub-array and the second programmable capacitor sub-array are the same. The first programmable capacitor sub-array includes several branches, and each branch includes a field effect transistor A <n-1>and more than one capacitor, field effect transistor A <n-1>The source of which is grounded, field effect transistor A <n-1>The drain is sequentially connected to node B after passing through the capacitor, where n is a natural number greater than or equal to 1.
[0007] A further technical solution is that: the oscillation amplification circuit includes a PMOS transistor P1 and an NMOS transistor N1. The drain of the PMOS transistor P1 is connected to the power supply. The source of the PMOS transistor P1 is connected to the drain of the NMOS transistor N1 and then connected to node A. The source of the NMOS transistor N1 is grounded. The gate of the PMOS transistor P1 is connected to the gate of the NMOS transistor N1 and then connected to node C.
[0008] A further technical solution is that: the oscillation circuit further includes a controller, and the feedback network and the programmable capacitor array are controlled by the controller.
[0009] The beneficial effects produced by adopting the above technical solution are as follows: The oscillation circuit of the present application adds a programmable negative feedback resistance adjustment circuit (feedback network) to the traditional crystal inverter oscillation circuit. This circuit can form different resistance values according to needs. In addition to being adaptable to the traditional quartz crystal oscillation circuit, it can also be adaptable to different resonators such as MEMS, FBAR, BAW, SAW and other resonators, and has a wider range of uses. The addition of the programmable capacitor array can expand the relevant programmable capacitor array according to the requirements of the actual oscillation circuit frequency calibration accuracy index, so as to form a high-precision temperature compensation frequency calibration circuit. Description of the Drawings
[0010] The following further describes the present invention in detail with reference to the drawings and specific embodiments.
[0011] Figure 1 is the schematic diagram of the oscillation circuit according to the embodiment of the present invention;
[0012] Figure 2 is the schematic diagram of the feedback network in the oscillation circuit according to the embodiment of the present invention;
[0013] Figure 3 is the equivalent diagram of the feedback network in the embodiment of the present invention;
[0014] Figure 4 is the schematic diagram of the first programmable capacitor sub-array in the embodiment of the present invention;
[0015] Figure 5 is the schematic diagram of the second programmable capacitor sub-array in the embodiment of the present invention. Detailed Embodiments
[0016] Combined with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.
[0017] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.
[0018] As Figure 1 shown, an oscillation circuit is disclosed in an embodiment of the present invention, which is characterized in that: it includes a resonator, and the resonator may include a crystal resonator, an FBAR resonator, a SAW resonator, a BAW resonator, or a MEMS resonator and other resonators. Two signal connection ends of the resonator are respectively connected to node B and node C, and a programmable capacitor array is connected between node B and node C and the resonator. One end of the feedback network is connected to node B, and the other end of the feedback network is connected to node C. Node B is connected to node A through resistor R1, and an oscillation amplification circuit is provided between node A and node C. Node A outputs a control signal after passing through amplifier A1 and amplifier A2 in sequence. The oscillation circuit further includes a controller, and the feedback network and the programmable capacitor array are controlled by the controller.
[0019] Furthermore, as Figure 1 and Figure 2 shown, the feedback network includes a plurality of PMOS transistors and a plurality of NMOS transistors. The drain of PMOS transistor P<0> is connected to the drain of NMOS transistor N<0> and then connected to node B. The source of PMOS transistor P<0> is connected to the source of NMOS transistor N<0> and then connected to the drain of PMOS transistor P<1> and the drain of NMOS transistor N<1>. The source of PMOS transistor P<1> and the source of NMOS transistor N<1> are connected and then connected to the drain of PMOS transistor P<2> and the drain of NMOS transistor N<2>, and so on. The source of PMOS transistor P <n-2>The source electrode of and NMOS transistor N <n-2>After the source electrode is connected, it is connected to PMOS transistor P <n-1>the drain of and NMOS transistor N <n-1>The drain connection of PMOS transistor P <n-1>The source of and NMOS transistor N <n-1>After the source electrode is connected, it is connected to the node C. The gates of the PMOS transistor and the NMOS transistor are control signal input terminals, and n is a natural number greater than or equal to 1.
[0020] As Figure 1 As shown, the oscillation amplification circuit includes a PMOS transistor P1 and an NMOS transistor N1. The drain of the PMOS transistor P1 is connected to the power supply. After the source of the PMOS transistor P1 is connected to the drain of the NMOS transistor N1, it is connected to the node A. The source of the NMOS transistor N1 is grounded. After the gates of the PMOS transistor P1 and the NMOS transistor N1 are connected, they are connected to the node C.
[0021] The resistor R1 between the node A and the node B is a resonator current-limiting resistor, which prevents excessive current during oscillation from affecting the reliability of the resonant device; the feedback network between the node B and the node C is used to adjust the feedback resistance of the amplification circuit. Furthermore, the feedback network and the oscillation amplification circuit form positive feedback. At the same time, different series combinations of PMOS transistors and NMOS transistors form programmable resistors to adjust the feedback negative resistance of the entire oscillation circuit to meet the requirements of different oscillators for negative resistance generation, and a negative resistance generation circuit is formed between the B and C nodes within a certain frequency range.
[0022] The programmable capacitor array is used for frequency calibration of the oscillation circuit. The overall resonator circuit seen from the B and C nodes towards the resonator presents an inductive characteristic, and together with the circuit that presents a capacitive characteristic when seen from the B and C nodes towards the oscillation amplification circuit as a whole, it forms an LC resonance characteristic. For the CMOS process, capacitor programming has the characteristics of high Q value, small chip area occupation, insensitivity to high and low temperatures, and good production consistency.
[0023] Feedback network working principle:
[0024] Figure 3 As shown, when the PMOS transistor or the NMOS transistor is turned on, the drain-source resistance is Rds. By different width-to-length ratios W / L of different PMOS transistors and different width-to-length ratios W / L of different NMOS transistors, different resistance values can be formed, thereby forming a programmable resistor array. Example: When the gate input of the PMOS transistor P<0> is at a low level, the PMOS transistor P<0> is turned on to form a resistor Rp<0>. When the gate input of the NMOS transistor N<0> is at a low level, the NMOS transistor N<0> is turned off to form an open circuit; when the gate of the PMOS transistor P<1> is at a high level, the PMOS transistor P<1> is turned off to form an open circuit. When the gate of the NMOS transistor N<1> is at a high level, the NMOS transistor N<1> is turned on to form a resistor Rn<1>; when the PMOS transistor P <n-2>When the gate of the PMOS transistor is at a low level, <n-2>Conduction forms a resistance Rp<0>, when NMOS transistor N <n-2>When it is at a high level, NMOS transistor N <n-2>When the transistor is turned on, a resistance Rn<n-2> is formed, and so on.
[0025] The programmable capacitor array includes a first programmable capacitor sub-array connected to node B and a second programmable capacitor sub-array connected to node C. The structures of the first programmable capacitor sub-array and the second programmable capacitor sub-array are the same. As Figure 4 shown, the first programmable capacitor sub-array includes several branches, and each branch includes a field effect transistor A <n-1>and more than one capacitor, field effect transistor A <n-1>The source of which is grounded, field effect transistor A <n-1>The drain electrodes are sequentially connected to node B after passing through the capacitors, where n is a natural number greater than or equal to 1. Figure 5 It is the circuit schematic diagram of the first programmable capacitor sub-array.
[0026] Programmable capacitor array: When fine-tuning the frequency, a metal MIM capacitor with small high and low temperature variations is required for frequency calibration. However, the minimum accuracy of the MIM capacitor is restricted by the CMOS process. Generally, the minimum size of the MIM capacitor in the CMOS process is 5um * 5um. According to the circuit principle, when capacitors are connected in series, their equivalent capacitance value is equal to the capacitance value divided by the number of series capacitors. In this way, a higher-precision capacitance value can be obtained. In the design of a high-precision temperature-compensated oscillator, this programmable capacitor array is directly connected to the AD / DA simply to form a high-precision frequency calibration circuit.
[0027] In summary, the oscillation circuit described in this application adds a feedback network to the traditional crystal inverter oscillation circuit. This circuit can form different resistor values according to needs. In addition to being adaptable to the traditional quartz crystal oscillation circuit, it can also be adaptable to different resonators, and has a wider range of uses. The addition of the programmable capacitor array can expand the relevant programmable capacitor array according to the requirements of the actual oscillation circuit frequency calibration accuracy index, so as to form a high-precision temperature-compensated frequency calibration circuit.
Claims
1. An oscillator circuit, characterized in that: The invention comprises a resonator, wherein two signal connection ends of the resonator are respectively connected to a node B and a node C, a programmable capacitor array is connected between the node B and the node C and the resonator, one end of a feedback network is connected to the node B, the other end of the feedback network is connected to the node C, the node B is connected to the node A via a resistor R1, an oscillation amplifier circuit is arranged between the node A and the node C, and the node A outputs a control signal after passing through amplifiers A1 and A2 in sequence.
2. The oscillator circuit according to claim 1, wherein: The resonator includes a crystal resonator, a FBAR resonator, a SAW resonator, a BAW resonator or a MEMS resonator.
3. The oscillator circuit according to claim 1, wherein: The feedback network includes a plurality of PMOS tubes and a plurality of NMOS tubes. <0> The drain of NMOS tube N <0> The drain of the PMOS tube is connected to the node B, and the PMOS tube P <0> The source of NMOS tube N <0> The source of the PMOS tube P <1> The drain of NMOS tube N <1> The drain connection of the PMOS tube P <1> The source of NMOS tube N <1> The source of the PMOS tube P <2> The drain of NMOS tube N <2> The drain connection of the PMOS tube P <n-2>The source of NMOS tube N <n-2>The source of the PMOS tube P <n-1>The drain of NMOS tube N <n-1>The drain connection of the PMOS tube P <n-1>The source of NMOS tube N <n-1> The source of the PMOS tube is connected to the node C, the gate of the PMOS tube and the gate of the NMOS tube are control signal input terminals, and n is a natural number greater than or equal to 1.< / n-1> 4. The oscillator circuit according to claim 1, wherein: The programmable capacitor array includes a first programmable capacitor subarray connected to node B and a second programmable capacitor subarray connected to node C. The first programmable capacitor subarray has the same structure as the second programmable capacitor subarray. The first programmable capacitor subarray includes a plurality of paths, each of which includes a field effect transistor A. <n-1>and one or more capacitors, FET A <n-1>The source of the field effect transistor A is grounded. <n-1> The drain of is connected to the node B through the capacitor in turn, and n is a natural number greater than or equal to 1.< / n-1> 5. The oscillator circuit according to claim 1, wherein: The oscillation amplifier circuit includes a PMOS tube P1 and an NMOS tube N1, the drain of the PMOS tube P1 is connected to a power supply, the source of the PMOS tube P1 is connected to the drain of the NMOS tube N1 and then connected to a node A, the source of the NMOS tube N1 is grounded, and the gate of the PMOS tube P1 is connected to the gate of the NMOS tube N1 and then connected to the node C.
6. The oscillator circuit according to claim 1, wherein: The oscillation circuit further includes a controller, and the feedback network and the programmable capacitor array are controlled by the controller.