A crystal oscillator oscillating circuit, bare die, chip and electronic device

Abstract

The embodiment of the present invention discloses a crystal oscillator starting circuit, including an oscillator starting module, a detection module and a control module; the crystal oscillator starting circuit includes two crystal oscillator interfaces for connecting a crystal oscillator. The detection module detects the connection mode between the crystal oscillator and the crystal oscillator interface under the drive of an external clock signal, and determines the oscillation mode of the oscillator starting module according to the connection mode; the control module controls the oscillator starting module to oscillate according to the oscillation mode under the drive of the external clock signal. The embodiment of the present invention can solve the technical problem that the current crystal oscillator starting circuit cannot flexibly adjust the oscillation mode.

Description

Technical Field

[0001] The present invention relates to the field of electronic circuits, and in particular to a crystal oscillator starting circuit, a bare die, a chip and an electronic device. Background Art

[0002] An oscillator is a circuit that can automatically convert DC power into an AC signal with a certain amplitude and frequency without the need for an external signal. An oscillator can generate an oscillation waveform with an accurate and stable frequency, which can be used to provide a clock signal for the chip.

[0003] The oscillator includes a frequency selection network and an amplifier. When the power supply turns on the oscillator, the noise interference in the circuit generates a transient current, which contains an extremely wide frequency band. However, under the frequency selection of the frequency selection network, the oscillator only selects the signal of its own resonant frequency. Under the positive feedback of the amplifier, the resonant frequency signal becomes stronger and stronger, thereby generating a sinusoidal oscillation waveform. After shaping the sinusoidal oscillation waveform, a square wave signal can be obtained. This square wave signal can be used as the clock signal of the chip.

[0004] The oscillator may include a crystal oscillator and a crystal oscillator start-up circuit. The crystal oscillator start-up circuit may be disposed inside the chip. The crystal oscillator may be disposed on a printed circuit board (PCB) outside the chip. The crystal oscillator is electrically connected to the crystal oscillator interface of the crystal oscillator start-up circuit through the pins of the chip, thereby forming an oscillator.

[0005] There are two types of crystal oscillator starting circuits. One is a single-ended starting mode crystal oscillator starting circuit, which includes a crystal oscillator interface, which leads to a pin on the chip, one port of the crystal oscillator is electrically connected to the pin on the PCB, and the other port of the crystal oscillator is electrically connected to the ground, thereby forming a single-ended starting mode oscillator. The other is a double-ended starting mode crystal oscillator starting circuit, in which two crystal oscillator interfaces lead to two pins on the chip, and the two ports of the crystal oscillator are electrically connected to the two pins on the PCB, thereby forming a double-ended starting mode oscillator.

[0006] The user's demand for a crystal oscillator starting circuit may be a single-ended starting mode crystal oscillator starting circuit or a double-ended starting mode crystal oscillator starting circuit, but the starting modes of the above two crystal oscillator starting circuits are fixed and cannot be flexibly adjusted according to the user's needs. Therefore, the current crystal oscillator starting circuit has a technical problem that the starting mode cannot be flexibly adjusted. Summary of the invention

[0007] To solve the above technical problems, the main purpose of the embodiments of the present invention is to provide a crystal oscillator starting circuit, a bare die, a chip and an electronic device to solve the technical problem that the current crystal oscillator starting circuit cannot flexibly adjust the starting mode.

[0008] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0009] A crystal oscillator starting circuit comprises an oscillator starting module, a detection module and a control module; the crystal oscillator starting circuit comprises two crystal oscillator interfaces to which a crystal oscillator can be connected; the detection module, driven by an external clock signal, detects the connection mode between the crystal oscillator and the crystal oscillator interface, and determines the oscillation mode of the oscillator starting module according to the connection mode; the control module, driven by the external clock signal, controls the oscillator starting module to oscillate according to the oscillation mode.

[0010] Preferably, the two crystal oscillator interfaces include a first crystal oscillator interface and a second crystal oscillator interface;

[0011] The detection module, driven by the external clock signal, sends a detection signal to the first crystal oscillator interface, and detects a difference between a signal of the first crystal oscillator interface and a signal of the second crystal oscillator interface;

[0012] If the difference is less than a set reference, it is determined that the first crystal oscillator interface and the second crystal oscillator interface are connected to corresponding ports of the crystal oscillator, and it is determined that the oscillation mode of the oscillation module is a double-end oscillation mode, and the control module controls the oscillation module to oscillate according to the double-end oscillation mode under the drive of the external clock signal;

[0013] If the difference is greater than a set benchmark, it is determined that only one of the first crystal oscillator interface and the second crystal oscillator interface is connected to one port of the crystal oscillator, and the oscillation mode of the oscillation module is determined to be a single-ended oscillation mode. The control module, driven by the external clock signal, controls the oscillation module to oscillate according to the single-ended oscillation mode.

[0014] Preferably, the detection module comprises a first multiplexer, a signal transmitter and a signal detector;

[0015] The signal transmitter sends a detection signal to the first crystal oscillator interface, and when the control module selects the first path, the first multiplexer outputs the signal of the first crystal oscillator interface, and the signal detector receives and records the signal of the first crystal oscillator interface;

[0016] The signal transmitter sends a detection signal to the first crystal oscillator interface. When the control module selects the second path, the first multiplexer outputs the signal of the second crystal oscillator interface. The signal detector receives the signal of the second crystal oscillator interface and detects the difference between the signal of the first crystal oscillator interface and the signal of the second crystal oscillator interface.

[0017] Preferably, the detection signal is a square wave signal; the signal detector includes a Schmitt trigger and a level flip detection unit;

[0018] When receiving the signal from the first crystal oscillator interface, the Schmitt trigger sends a first signal to the level flip detection unit, and the level flip detection unit detects the number of first level flips of the first signal within a preset time length;

[0019] When receiving the signal from the second crystal oscillator interface, the Schmitt trigger sends a second signal to the level flip detection unit, and the level flip detection unit detects the number of second level flips of the second signal within a preset time length;

[0020] The level flip detection unit compares the first level flip number with the second level flip number, and if the difference between the two numbers is less than a preset reference, it is determined that the oscillation mode of the oscillation module is a double-ended oscillation mode; if the difference between the two numbers is greater than the preset reference, it is determined that the oscillation mode of the oscillation module is a single-ended oscillation mode.

[0021] Preferably, the crystal oscillator starting circuit also includes a current source; the current source is used to provide current to the starting module in a double-ended starting mode and a single-ended starting mode respectively; when the current source is working, the current output end of the current source has a stable voltage drop relative to the power supply end; the current output end of the current source is electrically connected to the second crystal oscillator interface.

[0022] Preferably, the oscillation module comprises a first voltage amplifier, a second voltage amplifier, a first capacitor array and a second capacitor array;

[0023] The first electrode of the second capacitor array is electrically connected to the first crystal oscillator interface, the second electrode of the second capacitor array is electrically connected to the output end of the second multiplexer, and the two input ends of the second multiplexer are electrically connected to the ground end and the second crystal oscillator interface respectively; the number of the second multiplexer is at least one;

[0024] When the oscillation mode is a double-ended oscillation mode, the control module controls the second multiplexer to electrically connect the second capacitor array to the ground through the second multiplexer, so that the first voltage amplifier, the first capacitor array, the second capacitor array and the crystal oscillator form a double-ended mode oscillation circuit;

[0025] When the starting mode is a single-ended starting mode, the control module controls the second multiplexer to electrically connect the second capacitor array to the second crystal oscillator interface through the second multiplexer, so that the second voltage amplifier, the first capacitor array, the second capacitor array and the crystal oscillator form a single-ended mode starting oscillation circuit.

[0026] Preferably, the first capacitor array includes at least one first capacitor unit; each of the first capacitor units is connected in series with a first switch tube and in parallel with a second switch;

[0027] When the first capacitor unit needs to be used, the control module, driven by the external clock signal, turns on the first switch tube and turns off the second switch;

[0028] When the first capacitor unit is not needed, the control module, driven by the external clock signal, turns off the first switch tube and turns on the second switch.

[0029] Preferably, the second capacitor array includes at least one second capacitor unit; each of the second capacitor units is connected to one of the second multiplexers; each of the second capacitor units is connected in parallel to one of the third switch tubes;

[0030] When the oscillation mode of the oscillation module is a double-end oscillation mode and the second capacitor unit needs to be used, the control module, under the drive of the external clock signal, controls the second multiplexer to make the second capacitor unit electrically connected to the ground terminal through the second multiplexer, and disconnects the third switch tube;

[0031] When the oscillation mode of the oscillation module is a single-ended oscillation mode and the second capacitor unit needs to be used, the control module, under the drive of the external clock signal, controls the second multiplexer to make the second capacitor unit electrically connected to the second crystal oscillator interface through the second multiplexer, and disconnects the third switch tube;

[0032] When the second capacitor unit is not needed, the control module, driven by the external clock signal, controls the second multiplexer so that the second capacitor unit is not electrically connected to the second crystal oscillator interface and the ground terminal through the second multiplexer, and turns on the third switch tube.

[0033] Preferably, the crystal oscillator starting circuit further includes a current source; the current source provides a static bias current for the first voltage amplifier and the second voltage amplifier;

[0034] The current source receives a feedback signal from the first crystal oscillator interface, and adjusts the magnitude of the output current of the current source according to the feedback signal, so as to adjust the gain magnitude of the first voltage amplifier or the gain magnitude of the second voltage amplifier;

[0035] The feedback signal is used to characterize the amplitude of the oscillation waveform output by the crystal oscillator starting circuit.

[0036] Preferably, the current source comprises a first field effect transistor, and a gate of the first field effect transistor is used to receive the feedback signal;

[0037] When the amplitude of the feedback signal is greater than the first preset value, the first field effect transistor is in a non-fully conductive state in the negative half cycle of the feedback signal; the larger the amplitude of the feedback signal is, the smaller the current flowing through the first field effect transistor is in the negative half cycle of the feedback signal, the smaller the output current of the current source is, and the smaller the gain of the first voltage amplifier or the gain of the second voltage amplifier is;

[0038] When the amplitude of the feedback signal is less than the first preset value, in the negative half cycle of the feedback signal, the first field effect transistor is in a fully on state, the current flowing through the first field effect transistor is constant, the output current of the current source is also constant, and the gain of the first voltage amplifier or the gain of the second voltage amplifier is also constant.

[0039] Preferably, the current source further comprises a second field effect transistor, and the first field effect transistor and the second field effect transistor form a current mirror;

[0040] When the current flowing through the first field effect transistor is smaller, the current flowing through the second field effect transistor is also smaller, and the output current of the current source is also smaller.

[0041] A bare chip comprises any one of the above-mentioned crystal oscillator starting circuits.

[0042] A chip comprises any of the above-mentioned bare chips.

[0043] An electronic device comprises any one of the aforementioned chips.

[0044] In the embodiment of the present invention, the detection module can automatically detect the connection mode between the crystal oscillator and the crystal oscillator interface under the drive of the external clock signal, and determine the oscillation mode of the oscillator module according to the connection mode. Then, the control module can control the oscillator module to oscillate according to the above oscillation mode under the drive of the external clock signal. Therefore, the crystal oscillator oscillation circuit in the embodiment of the present invention can flexibly adjust the oscillation mode.

[0045] Other beneficial effects of the present invention will be explained in the specific implementation manner through the introduction of specific technical features and technical solutions. Through the introduction of these technical features and technical solutions, those skilled in the art should be able to understand the beneficial technical effects brought about by the technical features and technical solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[0047] Figure 1A schematic diagram of the structure of a crystal oscillator starting circuit according to a preferred embodiment of the present invention;

[0048] Figure 2 It is a structural schematic diagram of a crystal oscillator starting circuit in a dual-mode starting mode according to a preferred embodiment of the present invention;

[0049] Figure 3 It is a structural schematic diagram of a crystal oscillator starting circuit in a single-mode starting mode according to a preferred embodiment of the present invention;

[0050] Figure 4 A schematic diagram of the structure of a detection module according to a preferred embodiment of the present invention;

[0051] Figure 5 A schematic diagram of the structure of a signal detector according to a preferred embodiment of the present invention;

[0052] Figure 6 It is a structural schematic diagram of a crystal oscillator starting circuit according to another preferred embodiment of the present invention;

[0053] Figure 7 A schematic structural diagram of an oscillating module according to a preferred embodiment of the present invention;

[0054] Figure 8 It is a structural schematic diagram of a double-end starting mode oscillator circuit according to a preferred embodiment of the present invention;

[0055] Fig. 9 A schematic diagram of the structure of a single-ended oscillation mode oscillator circuit according to a preferred embodiment of the present invention;

[0056] Fig.10 is a schematic structural diagram of a first capacitor array according to a preferred embodiment of the present invention;

[0057] Fig.11 is a structural schematic diagram of a second capacitor array according to a preferred embodiment of the present invention;

[0058] Fig.12 It is a structural schematic diagram of a crystal oscillator starting circuit according to another preferred embodiment of the present invention;

[0059] Fig.13 Schematic diagram of the structure of a current source according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0060] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail. In order to avoid confusing the essence of the present invention, known methods, processes, procedures, and components are not described in detail.

[0061] In addition, persons of ordinary skill in the art will appreciate that the drawings provided herein are for illustration purposes and are not necessarily drawn to scale.

[0062] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include", "comprising" and similar words should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to".

[0063] In the description of the present invention, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0064] To facilitate understanding of the technical solutions of the embodiments of the present invention, the terms involved in the embodiments of the present invention are first explained below.

[0065] The Schmitt trigger has two stable states, but unlike general triggers, the Schmitt trigger uses a potential triggering method, and its state is maintained by the input signal potential. For input signals with two different change directions, negative decreasing and positive increasing, the Schmitt trigger has different threshold voltages. When the input voltage is higher than the positive threshold voltage, the Schmitt trigger outputs a high level; when the input voltage is lower than the negative threshold voltage, the Schmitt trigger outputs a low level. When the input voltage is between the positive and negative threshold voltages, the Schmitt trigger output level does not change.

[0066] Next, the crystal oscillator starting circuit provided by the embodiment of the present invention is introduced.

[0067] Figure 1 FIG. 2 shows a schematic diagram of the structure of a crystal oscillator starting circuit provided by an embodiment of the present invention. Figure 1 As shown, the crystal oscillator oscillator circuit 1 includes an oscillator module 11, a detection module 12 and a control module 13. The crystal oscillator oscillator circuit 1 may include two crystal oscillator interfaces for connecting a crystal oscillator, and specifically, the two crystal oscillator interfaces may be provided on the oscillator module 11. Exemplarily, the two crystal oscillator interfaces may be a first crystal oscillator interface 111 and a second crystal oscillator interface 112, respectively.

[0068] like Figure 1As shown, the crystal oscillator oscillator circuit 1 can be located in a bare die, and after the bare die is packaged with a packaging material, it becomes a chip. After packaging, the relevant interfaces of the crystal oscillator oscillator circuit 1 are the relevant interfaces of the chip, which usually exist in the form of pins.

[0069] The oscillation mode of the oscillator module 11 can be divided into a single-ended oscillation mode and a double-ended oscillation mode. In the single-ended oscillation mode, one port of the crystal oscillator 2 can be electrically connected to one of the two crystal oscillator interfaces, and the other port of the crystal oscillator 2 can be electrically connected to the ground terminal, such as Figure 2 As shown. At this time, crystal oscillator 2 only needs to occupy one pin of the chip.

[0070] In the double-end oscillator mode, the two ports of crystal oscillator 2 are electrically connected to the two crystal oscillator interfaces mentioned above. At this time, crystal oscillator 2 needs to occupy two pins of the chip, such as Figure 3 shown.

[0071] Compared with the single-ended oscillator consisting of the oscillator module 11 and the crystal oscillator 2 in the single-ended oscillator mode, the double-ended oscillator consisting of the oscillator module 11 and the crystal oscillator 2 in the double-ended oscillator mode has better performance in terms of output oscillation waveform frequency, temperature drift, output clock jitter, etc.

[0072] In an actual application scenario, before packaging the bare chip, the user can select the corresponding starting mode according to his actual needs. For example, user A has low requirements on the performance of the oscillator, and the pin resources of the chip are relatively tight, so the single-ended starting mode can be selected. In this way, the chip manufacturer can package the bare chip according to the specific needs of user A to form chip A0. The specific packaging method can be to lead out the first crystal oscillator interface 111 as pin A00, and retain the first crystal oscillator interface 112 in the form of a solder joint, and not lead out as a pin. When using chip A0, user A can solder chip A0 and crystal oscillator 2 on the PCB. And the pin A00 of chip A0 is connected to one end of the crystal oscillator 2 by welding, and the other end of the crystal oscillator 2 can be electrically connected to the ground.

[0073] Similarly, user B has higher requirements for the performance of the oscillator, and the chip has more abundant pin resources, so the double-ended oscillation mode can be selected. In this way, the chip manufacturer can package the bare chip according to the specific needs of user B to form chip B0. The specific packaging method can be to lead out the first crystal oscillator interface 111 as pin A00, and lead out the first crystal oscillator interface 112 as pin A01. When using chip B0, user B can solder chip B0 and crystal oscillator 2 on the PCB. And pin A00 and pin A01 of chip B0 are respectively connected to the two ports of crystal oscillator 2 by welding.

[0074] In this way, chip manufacturers can only manufacture one die instead of two, which can meet the different needs of different users, and the cost of designing and taping one die is much lower than the cost of designing and taping two die.

[0075] Figure 1 The dotted line connected to the second crystal oscillator interface 112 in FIG. 1 indicates that the second crystal oscillator interface 112 may be led out as a pin or may not be led out as a pin.

[0076] The detection module 12 can enter a working state under the drive of an external clock signal and detect the connection mode between the crystal oscillator 2 and the two crystal oscillator interfaces.

[0077] It should be noted that the external clock signal is generated by an external clock signal generator located outside the crystal oscillator oscillating circuit 1. The external clock signal generator is different from the oscillator formed by the crystal oscillator oscillating circuit 1 and the crystal oscillator 2 in the embodiment of the present invention. After being powered on, the external clock signal generator can enter the working state and generate an external clock signal, which enters the crystal oscillator oscillating circuit 1 through the relevant clock interface for use by the control module 13 and the detection module 12. In addition, the external clock signal generator can also be located in the bare chip.

[0078] In these two oscillation modes, the connection modes of the crystal oscillator 2 and the two crystal oscillator interfaces are different. Therefore, the detection module 12 can determine whether the oscillation mode of the oscillation module 11 is the single-end oscillation mode or the double-end oscillation mode by detecting the connection mode between the crystal oscillator 2 and the crystal oscillator interface.

[0079] Specifically, if the detection module 12 detects that the crystal oscillator 2 is electrically connected to the first crystal oscillator interface 111 and the second crystal oscillator interface 112 at the same time, it can be determined that the oscillation mode of the oscillator module 11 is a double-end oscillation mode. Therefore, the oscillator module 11 can be driven by an external clock signal to control the oscillator module 11 to oscillate in a double-end oscillation mode to form a double-end oscillator mode oscillator. The double-end oscillator mode oscillator can generate a sinusoidal oscillation waveform for generating a clock signal. Therefore, for user B, the crystal oscillator oscillation circuit 1 provided in the embodiment of the present invention can enable the oscillator module 11 to oscillate in a double-end oscillation mode.

[0080] Similarly, if the detection module 12 detects that only one of the first crystal oscillator interface 111 and the second crystal oscillator interface 112 is electrically connected to a port of the crystal oscillator 2, it can be determined that the oscillation mode of the oscillation module 11 is a single-ended oscillation mode. Therefore, the oscillation module 11 can be driven by an external clock signal to control the oscillation module 11 to oscillate in the single-ended oscillation mode to form a single-ended oscillation mode oscillator. The single-ended oscillation mode oscillator can generate a sinusoidal oscillation waveform for generating a clock signal. Therefore, for user A, the crystal oscillator oscillation circuit 1 provided in the embodiment of the present invention can enable the oscillation module 11 to oscillate in a single-ended oscillation mode.

[0081] It can be seen that when the crystal oscillator oscillator circuit 1 in the embodiment of the present invention is powered on, the detection module 12 can automatically detect the connection mode between the crystal oscillator 2 and the two crystal oscillator interfaces, and determine the oscillation mode of the oscillator module 11 according to the connection mode. Then, the control module 13 can control the oscillator module 11 to oscillate according to the oscillation mode determined above. Therefore, the crystal oscillator oscillator circuit 1 in the embodiment of the present invention can automatically and flexibly adjust the oscillation mode according to the connection mode between the crystal oscillator 2 and the two crystal oscillator interfaces.

[0082] In some embodiments of the present invention, Figure 1 As shown, the two crystal oscillator interfaces can be the first crystal oscillator interface 111 and the second crystal oscillator interface 112. Driven by the external clock signal, the detection module 12 can send a detection signal to the first crystal oscillator interface 111 and detect the difference between the signal of the first crystal oscillator interface 111 and the signal of the second crystal oscillator interface 112.

[0083] If the difference between the two is less than the set reference, it indicates that the detection signal can be transmitted from the first crystal oscillator interface 111 to the second crystal oscillator interface 112 through the crystal oscillator 2. Therefore, the detection module 12 can determine that the crystal oscillator is connected between the first crystal oscillator interface 111 and the second crystal oscillator interface 112. Figure 3 As shown. It can be determined that the oscillation mode of the oscillation module 11 is the double-ended oscillation mode. Then, the control module 13, driven by the external clock signal, can control the oscillation module 11 to oscillate in the double-ended oscillation mode to form a double-ended oscillator.

[0084] Similarly, if the difference between the two is greater than the set reference, it indicates that the detection signal cannot be transmitted from the first crystal oscillator interface 111 to the second crystal oscillator interface 112 through the crystal oscillator 2. Figure 2 Therefore, the detection module 12 can determine that the crystal oscillator is not connected between the first crystal oscillator interface 111 and the second crystal oscillator interface 112, and further determine that the oscillation mode of the oscillation module 11 is the single-ended oscillation mode. Then, the control module 13, driven by the external clock signal, controls the oscillation module 11 to oscillate in the single-ended oscillation mode to form a single-ended oscillator.

[0085] In some embodiments of the present invention, Figure 4 As shown, the detection module 12 may include a first multiplexer 121, a signal transmitter 122, and a signal detector 123. The first multiplexer 121 may be provided with a first input terminal 1211 and a second input terminal 1212. The first input terminal 1211 may be electrically connected to the output terminal of the signal transmitter 122 and the first crystal oscillator interface 111, respectively, and the second input terminal 1212 may be electrically connected to the second crystal oscillator interface 112. The first multiplexer 121 may also be provided with a first output terminal 1213.

[0086] The first multiplexer 121 may be provided with a gate terminal 1214 which may be electrically connected to the control module 13. The control module 13 sends a corresponding gate control signal to the gate terminal to connect the first input terminal 1211 or the second input terminal 1212 with the first output terminal 1213.

[0087] The signal transmitter 122 can send a detection signal to the first crystal oscillator interface 111. The control module 13 sends a first selection signal (e.g., a high-level signal) to the selection terminal, so that the first input terminal 1211 is connected to the first output terminal 1213. Therefore, the first output terminal 1213 can output the signal of the first crystal oscillator interface 111 (that is, the aforementioned detection signal), and the input terminal of the signal detector 123 can receive and record the signal of the first crystal oscillator interface 111.

[0088] Similarly, when the signal transmitter 122 sends a detection signal to the first crystal oscillator interface 111, the control module 13 sends a second selection signal (such as a low level signal) to the selection terminal, so that the second input terminal 1212 is connected to the first output terminal 1213. Therefore, the first output terminal 1213 can output the signal of the second crystal oscillator interface 112.

[0089] Next, the signal detector 123 may receive the signal of the second crystal oscillator interface 112 and detect the difference between the signal of the first crystal oscillator interface 111 and the signal of the second crystal oscillator interface 112 .

[0090] In some embodiments of the present invention, the detection signal sent by the signal transmitter 122 may be a square wave signal. Figure 5 As shown, the signal detector 123 may include a Schmitt trigger 1232 and a level flip detection unit 1233. The Schmitt trigger 1232 may be electrically connected to the input terminal 1231.

[0091] When the Schmitt trigger 1232 receives the signal from the first crystal oscillator interface 111, since the detection signal is a square wave signal, at the rising edge of the square wave signal, the voltage value of the signal from the first crystal oscillator interface 111 will pass through the positive threshold voltage of the Schmitt trigger 1232 during the increase process, so that the Schmitt trigger 1232 outputs a high level. At the falling edge of the square wave signal, the voltage value of the signal from the first crystal oscillator interface 111 will pass through the negative threshold voltage of the Schmitt trigger 1232 during the decrease process, so that the Schmitt trigger 1232 outputs a low level. In this way, the level of the signal (recorded as the first signal) output by the Schmitt trigger 1232 is in a state of continuous flipping. The level flip detection unit 1233 receives the first signal, and then detects the number of level flips of the first signal within a preset time length (for example, 1s) (recorded as the first level flip number).

[0092] In the single-ended oscillator mode, the crystal oscillator 2 is only electrically connected to the first crystal oscillator interface 111, but not to the second crystal oscillator interface 112. Therefore, the detection signal cannot be transmitted to the second crystal oscillator interface 112 through the crystal oscillator 2, and the signal of the second crystal oscillator interface 112 cannot trigger the level flip of the second signal output by the Schmitt trigger 1232.

[0093] Similarly, in the dual-end oscillation mode, the crystal oscillator 2 is connected between the first crystal oscillator interface 111 and the second crystal oscillator interface 112. Therefore, the detection signal can be transmitted to the second crystal oscillator interface 112 through the crystal oscillator 2. The signal of the second crystal oscillator interface 112 can trigger the level flip of the second signal output by the Schmitt trigger 1232, which is different from the single-end oscillation mode.

[0094] By using the above characteristics, the Schmitt trigger 1232 can output the second signal when receiving the signal from the second crystal oscillator interface 112. The level flip detection unit 1233 receives the second signal and then detects the number of level flips of the second signal within a preset time (e.g., 1s) (recorded as the second level flip number).

[0095] If the difference between the second level flip number and the first level flip number is greater than a preset benchmark, it indicates that the signal of the second crystal oscillator interface 112 cannot trigger the level flip of the second signal output by the Schmitt trigger 1232, and the crystal oscillator 2 is not electrically connected to the first crystal oscillator interface 111 and the second crystal oscillator interface 112 at the same time. Therefore, it can be determined that the oscillation mode of the oscillation module 11 is a single-ended oscillation mode.

[0096] If the difference between the second level flip number and the first level flip number is less than a preset benchmark, it indicates that the signal of the second crystal oscillator interface 112 can trigger the level flip of the second signal output by the Schmitt trigger 1232, and the crystal oscillator 2 is electrically connected to the first crystal oscillator interface 111 and the second crystal oscillator interface 112 at the same time, so it can be determined that the oscillation mode of the oscillation module 11 is a double-ended oscillation mode.

[0097] In some embodiments of the present invention, Figure 6 As shown, the crystal oscillator start-up circuit 1 also includes a current source 14. The current source 14 is used to provide a static bias current to the start-up module 11 in the double-end start-up mode and the single-end start-up mode, respectively, so that it can work normally. When the current source 14 is working, the current output terminal 141 has a stable voltage drop relative to the power supply terminal. Therefore, the voltage of the current output terminal 141 is equal to the power supply terminal voltage minus the stable voltage drop, so the voltage of the current output terminal 141 is a constant value. Since the current output terminal 141 is electrically connected to the second crystal oscillator interface 112, the voltage of the second crystal oscillator interface 112 is also a constant value.

[0098] On this basis, when the oscillation mode is the single-ended oscillation mode, the detection signal cannot be transmitted to the second crystal oscillator interface 112 through the crystal oscillator 2. Therefore, the voltage of the second crystal oscillator interface 112 remains constant, and the voltage of the second crystal oscillator interface 112 does not cause the level of the second signal output by the Schmitt trigger 1232 to flip.

[0099] Similarly, when the oscillation mode is the double-ended oscillation mode, the detection signal can be transmitted to the second crystal oscillator interface 112 through the crystal oscillator 2. Therefore, the voltage of the second crystal oscillator interface 112 is equal to the sum of the voltage of the current output terminal 141 of the current source 14 and the voltage of the detection signal, so the level of the second signal output by the Schmitt trigger 1232 is flipped.

[0100] In some embodiments of the present invention, Figure 7 As shown, the oscillator module 11 may include a first voltage amplifier 113, a second voltage amplifier 114, a first capacitor array 115, and a second capacitor array 116. The first capacitor array 115 may be connected between the second crystal oscillator interface 112 and the ground terminal.

[0101] The first pole 1161 of the second capacitor array 116 can be electrically connected to the first crystal oscillator interface 111, and the second pole 1162 of the second capacitor array 116 can be electrically connected to the output terminal 1171 of the second multiplexer 117. The second multiplexer 117 is provided with two input terminals, namely, a third input terminal 1172 and a fourth input terminal 1173. The third input terminal 1172 is electrically connected to the ground terminal, and the fourth input terminal 1173 is electrically connected to the second crystal oscillator interface 112. Exemplarily, the first pole can be a positive pole, and the second pole can be a negative pole. The number of capacitor units in the second capacitor array 116 is at least one, and accordingly, the number of the second multiplexer 117 is also at least one.

[0102] When the oscillation mode is the double-ended oscillation mode, the control module 13 can control the second multiplexer 117 to connect the output terminal 1171 with the third input terminal 1172, so that the second capacitor array 116 is electrically connected to the ground terminal through the second multiplexer 117. In this way, the first voltage amplifier, the first capacitor array 115, the second capacitor array 116 and the crystal oscillator can form a double-ended mode oscillation circuit.

[0103] In a specific implementation, the double-ended mode oscillation circuit is as follows: Figure 8 As shown. The second voltage amplifier includes a field effect transistor Mn10, resistors R4 and R5. The second capacitor array 116 is substantially electrically connected to the ground terminal through a second multiplexer 117. It should be noted that in order to make the circuit diagram look more concise, Figure 8 The second multiplexer 117 is not shown.

[0104] When the oscillation start-up mode is the single-ended oscillation start-up mode, the control module 13 controls the second multiplexer 117 so that the output terminal 1171 is connected to the fourth input terminal 1173, and the second capacitor array 116 is electrically connected to the second crystal oscillator interface 112 through the second multiplexer 117. In this way, the second voltage amplifier, the first capacitor array 115, the second capacitor array 116 and the crystal oscillator 2 form a single-ended mode oscillation start-up circuit.

[0105] In a specific implementation, the single-ended mode oscillation circuit is as follows: Fig. 9 As shown. The first voltage amplifier 113 includes a field effect transistor Mp5 and a resistor R6. The second capacitor array 116 is substantially electrically connected to the second crystal oscillator port through a second multiplexer 117. It should be noted that in order to make the circuit look more concise, Fig. 9 The second multiplexer 117 is not shown.

[0106] In some embodiments of the present invention, Fig.10 As shown, the first capacitor array 115 includes at least one first capacitor unit 1151. Each first capacitor unit 1151 can be connected in series with a first switch tube 1152 and in parallel with a second switch 1153.

[0107] When the first capacitor unit 1151 needs to be used, the control module 13 can turn on the first switch tube 1152 and turn off the second switch 1153 under the drive of the external clock signal, so that the first capacitor unit 1151 can be electrically connected to the ground end, and the first capacitor unit 1151 is in a working state, that is, the capacitance of the first capacitor array 115 includes the capacitance of the first capacitor unit 1151. When the number of first capacitor units 1151 to be used is multiple, the above method can be used to operate each first capacitor unit 1151.

[0108] It should be noted that the control module 13 can change the capacitance of the first capacitor array 115 by controlling the number of first capacitor units 1151 electrically connected to the ground, thereby changing the amplitude of the sinusoidal oscillation waveform output by the oscillator and the time required for the crystal oscillator oscillation circuit 1 to oscillate.

[0109] In a specific implementation, the first switch tube 1152 may be an N-type field effect tube, and the control module 13 may control the gate level of the N-type field effect tube to realize on-off control of the first switch tube 1152. A transmission gate may be used to realize parallel connection with the first capacitor unit 1151. In one case, the second switch 1153 may be a transmission gate switch.

[0110] When the first capacitor unit 1151 is not needed, the control module 13 can control the first switch tube 1152 to a non-conducting state under the drive of an external clock signal, so that the first capacitor unit 1151 is not electrically connected to the ground and is in an idle state. In this way, the capacitance of the first capacitor array 115 does not include the capacitance of the first capacitor unit 1151.

[0111] At this time, the first switch tube 1152 is in a high impedance state, and the second pole 11512 is electrically connected to the ground through the first switch tube 1152 in a non-conducting state. The first pole 11511 is electrically connected to the second crystal oscillator interface 112, and the voltage of the second crystal oscillator interface 112 includes both a DC component and an AC component, wherein the AC component is a voltage of a sine waveform.

[0112] If the second switch 1153 is not connected in parallel with the first capacitor unit 1151, the AC component of the voltage of the second crystal oscillator interface 112 will be transmitted to the second pole 11512 through the first capacitor unit 1151, while the DC component cannot be transmitted, because the first capacitor unit 1151 has the characteristics of passing AC and blocking DC. In the negative half cycle of the AC component, the voltage value of the second pole 11512 is negative, so noise will be injected into the substrate corresponding to the first switch tube 1152, so that the output oscillation waveform will include more jitter and noise.

[0113] The embodiment of the present invention adopts the second switch 1153 connected in parallel with the first capacitor unit 1151. When the first capacitor unit 1151 is not needed, the control module 13 can turn on the second switch 1153 to make the potentials of the first pole 11511 and the second pole 11512 almost equal, so that the voltage of the second pole 11512 includes both the aforementioned AC component and the aforementioned DC component. In this way, due to the presence of the DC component, even in the negative half cycle of the AC component, the voltage value of the second pole 11512 always remains positive, so that noise will not be injected into the substrate corresponding to the first switch tube 1152, thereby reducing the jitter and noise included in the output oscillation waveform and improving the quality of the output oscillation waveform.

[0114] The embodiment of the present invention connects the second switch 1153 in parallel with the first capacitor unit 1151, and turns on the second switch 1153 when the first capacitor unit 1151 is not used, thereby reducing jitter and noise included in the output oscillation waveform and improving the quality of the output oscillation waveform.

[0115] In some embodiments of the present invention, Fig.11 As shown, the second capacitor array 116 includes at least one second capacitor unit 1161. Each second capacitor unit 1161 is connected to a second multiplexer 117, and each second capacitor unit 1161 is connected to a third switch tube 1162 in parallel.

[0116] When the oscillation mode of the oscillation module 11 is a double-end oscillation mode, and the second capacitor unit 1161 needs to be used, the control module 13 can control the second multiplexer 117 under the drive of the external clock signal, so that the second capacitor unit 1161 is electrically connected to the ground terminal through the second multiplexer 117, and the third switch tube 1162 is disconnected. When the number of second capacitor units 1161 to be used is multiple, the above method is used to operate each second capacitor unit 1161. In this way, the oscillation mode of the oscillation module 11 can be made into a double-end oscillation mode. Among them, the capacitance of the second capacitor array 116 is equal to the sum of the capacitances of all the second capacitor units 1161 that need to be used.

[0117] When the oscillation mode of the oscillation module 11 is a single-ended oscillation mode, and the second capacitor unit 1161 needs to be used, the control module 13, under the drive of the external clock signal, can control the second multiplexer 117 so that the second capacitor unit 1161 is electrically connected to the second crystal oscillator interface 112 through the second multiplexer 117, and the third switch tube 1162 is disconnected. When the number of second capacitor units 1161 to be used is multiple, the above method is used to operate each second capacitor unit 1161. In this way, the oscillation mode of the oscillation module 11 can be made into a single-ended oscillation mode. Among them, the capacitance of the second capacitor array 116 is equal to the sum of the capacitances of all the second capacitor units 1161 that need to be used.

[0118] When the second capacitor unit 1161 is not needed, the control module 13 can control the second multiplexer 117 under the drive of the external clock signal, so that the second capacitor unit 1161 is not electrically connected to the second crystal oscillator interface 112 and the ground terminal through the second multiplexer 117, and is in an idle state, so that the capacitance of the second capacitor array 116 does not include the capacitance of the second capacitor unit 1161. At this time, the second electrode 11612 of the second capacitor unit 1161 and the ground terminal are in a high impedance state. The control module 13 can also turn on the third switch tube 1162, so that the potentials of the first electrode 11611 and the second electrode 11612 of the second capacitor unit 1161 are almost equal.

[0119] Similar to the previous description, the embodiment of the present invention connects the third switch tube 1162 in parallel with the second capacitor unit 1161, and turns on the third switch tube 1162 without using the second capacitor unit 1161, so that the voltage of the second pole 11612 can always remain positive, thereby reducing the jitter and noise included in the output oscillation waveform and improving the quality of the output oscillation waveform.

[0120] In some embodiments of the present invention, Fig.12 As shown, the crystal oscillator starting circuit 1 may further include a current source 14. The current source 14 may be provided with a current output terminal 141 and a feedback receiving terminal 142. The current source 14 may provide a static bias current for the first voltage amplifier 113 and the second voltage amplifier 114 through the current output terminal 141, so that the first voltage amplifier 113 and the second voltage amplifier 114 can work normally.

[0121] The current source 14 can receive a feedback signal from the first crystal oscillator interface 111 through the feedback receiving terminal 142. The feedback signal is a sine waveform, which represents the amplitude of the oscillation waveform output by the crystal oscillator starting circuit 1. The current source 14 can adjust the output current of the current source 14 according to the feedback signal, so that the gain of the first voltage amplifier 113 can be adjusted when the starting mode is a double-ended starting mode, or the gain of the second voltage amplifier 114 can be adjusted when the starting mode is a single-ended starting mode, so as to achieve the purpose of adjusting the amplitude of the oscillation waveform output by the crystal oscillator starting circuit 1.

[0122] Specifically, when the amplitude of the feedback signal is large, the current source 14 can reduce the output current of the current source 14, thereby reducing the gain of the first voltage amplifier 113 or the gain of the second voltage amplifier 114, thereby reducing the amplitude of the oscillation waveform. When the amplitude of the feedback signal is small, the current source 14 can increase the output current of the current source 14, thereby increasing the gain of the first voltage amplifier 113 or the gain of the second voltage amplifier 114, thereby increasing the amplitude of the oscillation waveform. In this way, the automatic control of the amplitude of the oscillation waveform can be achieved, so that the amplitude of the oscillation waveform is stabilized within a preset range.

[0123] In some embodiments of the present invention, the current source 14 includes a first field effect transistor, the gate of the first field effect transistor can be used to receive a feedback signal, and the gate voltage of the first field effect transistor is equal to the voltage of the feedback signal plus a DC bias voltage. In the positive half cycle of the feedback signal, the gate voltage of the first field effect transistor is higher, and the first field effect transistor is always in a fully turned-on state.

[0124] Since the larger the amplitude of the feedback signal, the lower the voltage value of the feedback signal in the negative half cycle. Therefore, when the amplitude of the feedback signal is greater than the first preset value, the first field effect tube will be in a non-fully conductive state in the negative half cycle of the feedback signal. The larger the amplitude of the feedback signal, the smaller the gate voltage of the first field effect tube, the larger the equivalent impedance between the source and drain of the first field effect tube, the smaller the current flowing through the first field effect tube, and the smaller the output current of the current source 14, which makes the gain of the first voltage amplifier 113 or the gain of the second voltage amplifier 114 smaller, thereby reducing the amplitude of the oscillation waveform.

[0125] When the amplitude of the feedback signal is less than the first preset value, in the negative half cycle of the feedback signal, the first field effect tube is in a fully on state, and the equivalent impedance between the source and the drain of the first field effect tube is small and remains unchanged. Therefore, the current flowing through the first field effect tube is constant, the output current of the current source 14 is also constant, and the gain of the first voltage amplifier 113 or the gain of the second voltage amplifier 114 is also constant and large, thereby increasing the amplitude of the oscillation waveform.

[0126] In some embodiments of the present invention, the current source 14 further includes a second field effect transistor, and the first field effect transistor and the second field effect transistor form a current mirror. When the current flowing through the first field effect transistor is smaller, the current flowing through the second field effect transistor is also smaller, and the output current of the current source 14 is also smaller, thereby reducing the amplitude of the oscillation waveform.

[0127] In a specific implementation, the circuit schematic diagram of the current source 14 is as follows: Fig.13 The current source 14 may include an ideal current source I1 and an ideal current source I2, and also include resistors R1-R3, capacitors C1 and C2, N-type field effect transistors Mn1-Mn8, and P-type field effect transistors Mp1-Mp4.

[0128] Among them, the ideal current source I1 is connected to one end of the resistor R1, and the gates of the field effect transistors Mn1 and Mn2. The other end of the resistor R1 is connected to the drain of the field effect transistor Mn1, and the gates of the field effect transistors Mn3 and Mn4. The source of the field effect transistor Mn1 is connected to the drain of the field effect transistor Mn3, the source of the field effect transistors Mn3 and Mn4 is grounded, the drain of the field effect transistor Mn2 is connected to the field effect transistor Mp1, and the source is connected to the drain of the field effect transistor Mn4. The current mirror of the cascode structure composed of the field effect transistors Mn1~Mn4 and the field effect transistor Mn6 copies the current of the ideal current source I1.

[0129] The voltage drop of the current output terminal 141 relative to the power supply voltage VDD is the voltage between the source and drain of the field effect transistor Mp3 plus the voltage between the source and drain of the field effect transistor Mp4, so the voltage of the current output terminal 141 is a constant value.

[0130] The feedback receiving terminal 142 receives the feedback signal from the first crystal oscillator interface 111. The feedback signal is coupled to Mn8 through the capacitor C1 and the resistors R3, R2 and the capacitor C2 to form a low-pass filter, which filters out the AC signal in the feedback signal and only retains the DC part, thereby providing a DC bias voltage for the field effect transistor Mn7. The current mirror composed of Mn7 and Mn8 replicates the current of the ideal current source I2. The field effect transistor Mn5 merges the N-type replicated currents of the two sets of current mirrors, converts the N-type current into a P-type current through the field effect transistor Mp2, and then outputs it through the current output terminal 141 after being replicated by the field effect transistors Mp3 and Mp4.

[0131] The first field effect transistor may specifically be a field effect transistor Mn8. Fig.13The feedback receiving terminal 142 in the circuit is electrically connected to the first crystal oscillator interface 111, and receives the feedback signal from the first crystal oscillator interface 111. When the amplitude of the feedback signal is greater than the first preset value, in the negative half cycle of the feedback signal, the field effect tube Mn8 is in a non-fully conductive state. The larger the amplitude of the feedback signal, the smaller the gate voltage of the field effect tube Mn8 in the negative half cycle of the feedback signal, the larger the equivalent impedance between the source and the drain of the field effect tube Mn8, the larger the current flowing through the resistor R2 and the resistor R3, and the current output by the constant current source I2 is a constant value, so the current flowing through the field effect tube Mn8 is smaller. Since the field effect tube Mn7 and the field effect tube Mn8 form a current mirror, the current flowing through the field effect tube Mn7 is also smaller. At the same time, since the current flowing through the field effect tube Mn6 is unchanged, the current flowing through the field effect tube Mn5 is also smaller, so the current flowing through the field effect tube Mp2 is also smaller, and the current output by the current output terminal 141 is also smaller. This makes the gain of the first voltage amplifier 113 or the gain of the second voltage amplifier 114 smaller, thereby reducing the amplitude of the oscillation waveform.

[0132] Similarly, when the amplitude of the feedback signal is less than the first preset value, in the negative half cycle of the feedback signal, the field effect transistor Mn8 is in a fully on state, the current flowing through the field effect transistor Mn8 is constant, the current flowing through the field effect transistor Mn7 is also constant, resulting in the current flowing through the field effect transistor Mn5 being constant, the current output by the current output terminal 141 is also constant, and the gain of the first voltage amplifier 113 or the gain of the second voltage amplifier 114 is also constant and large, thereby increasing the amplitude of the oscillation waveform.

[0133] It is understandable that the structure of the crystal oscillator starting circuit 1 illustrated in the embodiment of the present invention does not constitute a specific limitation on the crystal oscillator starting circuit 1. In other embodiments of the present invention, the crystal oscillator starting circuit 1 may include more or fewer components than shown in the figure, or combine some components, or split some components, or arrange the components differently.

[0134] The above is an introduction to the crystal oscillator start-up circuit 1 provided in the embodiment of the present invention. Next, based on the above content, the embodiment of the present invention further provides a bare chip. The bare chip may include any of the crystal oscillator start-up circuits 1 described in the above embodiments, and the relevant introduction of the bare chip can refer to the above description.

[0135] The embodiment of the present invention further provides a chip. The chip may include any of the above-mentioned bare chips, and after the bare chip is packaged, it becomes a chip. The relevant introduction of the chip can refer to the above description.

[0136] An embodiment of the present invention further provides an electronic device, which may include any of the aforementioned chips.

[0137] Those skilled in the art will appreciate that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0138] It should be understood that the above-mentioned embodiments are merely illustrative and not restrictive. Without departing from the basic principles of the present invention, various obvious or equivalent modifications or substitutions that can be made by those skilled in the art to the above-mentioned details will all be included in the scope of the claims of the present invention.

Claims

1. A crystal oscillator starting circuit, comprising an oscillator starting module, characterized in that: It also includes a detection module and a control module; the crystal oscillator starting circuit includes two crystal oscillator interfaces for connecting the crystal oscillator; The detection module detects the connection mode between the crystal oscillator and the crystal oscillator interface under the drive of the external clock signal, and determines the oscillation mode of the oscillator module according to the connection mode; the control module controls the oscillator module to oscillate according to the oscillation mode under the drive of the external clock signal; The two crystal oscillator interfaces include a first crystal oscillator interface and a second crystal oscillator interface; The detection module, driven by the external clock signal, sends a detection signal to the first crystal oscillator interface, and detects a difference between a signal of the first crystal oscillator interface and a signal of the second crystal oscillator interface; If the difference is less than a set reference, it is determined that the first crystal oscillator interface and the second crystal oscillator interface are connected to corresponding ports of the crystal oscillator, and it is determined that the oscillation mode of the oscillation module is a double-end oscillation mode, and the control module controls the oscillation module to oscillate according to the double-end oscillation mode under the drive of the external clock signal; If the difference is greater than a set benchmark, it is determined that only one of the first crystal oscillator interface and the second crystal oscillator interface is connected to one port of the crystal oscillator, and the oscillation mode of the oscillation module is determined to be a single-ended oscillation mode. The control module, driven by the external clock signal, controls the oscillation module to oscillate according to the single-ended oscillation mode.

2. The crystal oscillator starting circuit according to claim 1, characterized in that: The detection module includes a first multiplexer, a signal transmitter and a signal detector; The signal transmitter sends a detection signal to the first crystal oscillator interface, and when the control module selects the first path, the first multiplexer outputs the signal of the first crystal oscillator interface, and the signal detector receives and records the signal of the first crystal oscillator interface; The signal transmitter sends a detection signal to the first crystal oscillator interface. When the control module selects the second path, the first multiplexer outputs the signal of the second crystal oscillator interface. The signal detector receives the signal of the second crystal oscillator interface and detects the difference between the signal of the first crystal oscillator interface and the signal of the second crystal oscillator interface.

3. The crystal oscillator starting circuit according to claim 2, characterized in that: The detection signal is a square wave signal; the signal detector includes a Schmitt trigger and a level flip detection unit; When receiving the signal from the first crystal oscillator interface, the Schmitt trigger sends a first signal to the level flip detection unit, and the level flip detection unit detects the number of first level flips of the first signal within a preset time length; When receiving the signal from the second crystal oscillator interface, the Schmitt trigger sends a second signal to the level flip detection unit, and the level flip detection unit detects the number of second level flips of the second signal within a preset time length; The level flip detection unit compares the first level flip number with the second level flip number, and if the difference between the two numbers is less than a preset reference, it is determined that the oscillation mode of the oscillation module is a double-ended oscillation mode; if the difference between the two numbers is greater than the preset reference, it is determined that the oscillation mode of the oscillation module is a single-ended oscillation mode.

4. The crystal oscillator starting circuit according to claim 1, characterized in that: It also includes a current source; the current source is used to provide current to the oscillation module in a double-ended oscillation mode and a single-ended oscillation mode respectively; when the current source is working, the current output end of the current source has a stable voltage drop relative to the power supply end; the current output end of the current source is electrically connected to the second crystal oscillator interface.

5. The crystal oscillator starting circuit according to claim 1, characterized in that: The oscillation module includes a first voltage amplifier, a second voltage amplifier, a first capacitor array and a second capacitor array; The first electrode of the second capacitor array is electrically connected to the first crystal oscillator interface, the second electrode of the second capacitor array is electrically connected to the output end of the second multiplexer, and the two input ends of the second multiplexer are electrically connected to the ground end and the second crystal oscillator interface respectively; the number of the second multiplexer is at least one; When the oscillation mode is a double-ended oscillation mode, the control module controls the second multiplexer to electrically connect the second capacitor array to the ground through the second multiplexer, so that the first voltage amplifier, the first capacitor array, the second capacitor array and the crystal oscillator form a double-ended mode oscillation circuit; When the starting mode is a single-ended starting mode, the control module controls the second multiplexer to electrically connect the second capacitor array to the second crystal oscillator interface through the second multiplexer, so that the second voltage amplifier, the first capacitor array, the second capacitor array and the crystal oscillator form a single-ended mode starting oscillation circuit.

6. The crystal oscillator starting circuit according to claim 5, characterized in that: The first capacitor array includes at least one first capacitor unit; each of the first capacitor units is connected in series with a first switch tube and in parallel with a second switch; When the first capacitor unit needs to be used, the control module, driven by the external clock signal, turns on the first switch tube and turns off the second switch; When the first capacitor unit is not needed, the control module, driven by the external clock signal, turns off the first switch tube and turns on the second switch.

7. The crystal oscillator starting circuit according to claim 5, characterized in that: The second capacitor array includes at least one second capacitor unit; each of the second capacitor units is connected to a second multiplexer; each of the second capacitor units is connected in parallel to a third switch tube; When the oscillation mode of the oscillation module is a double-end oscillation mode and the second capacitor unit needs to be used, the control module, under the drive of the external clock signal, controls the second multiplexer to make the second capacitor unit electrically connected to the ground terminal through the second multiplexer, and disconnects the third switch tube; When the oscillation mode of the oscillation module is a single-ended oscillation mode and the second capacitor unit needs to be used, the control module, under the drive of the external clock signal, controls the second multiplexer to make the second capacitor unit electrically connected to the second crystal oscillator interface through the second multiplexer, and disconnects the third switch tube; When the second capacitor unit is not needed, the control module, driven by the external clock signal, controls the second multiplexer so that the second capacitor unit is not electrically connected to the second crystal oscillator interface and the ground terminal through the second multiplexer, and turns on the third switch tube.

8. The crystal oscillator starting circuit according to claim 5, characterized in that: Also includes a current source; the current source provides a static bias current for the first voltage amplifier and the second voltage amplifier; The current source receives a feedback signal from the first crystal oscillator interface, and adjusts the magnitude of the output current of the current source according to the feedback signal, so as to adjust the gain magnitude of the first voltage amplifier or the gain magnitude of the second voltage amplifier; The feedback signal is used to characterize the amplitude of the oscillation waveform output by the crystal oscillator starting circuit.

9. The crystal oscillator starting circuit according to claim 8, characterized in that: The current source comprises a first field effect transistor, and a gate of the first field effect transistor is used to receive the feedback signal; When the amplitude of the feedback signal is greater than the first preset value, the first field effect transistor is in a non-fully conductive state in the negative half cycle of the feedback signal; the larger the amplitude of the feedback signal is, the smaller the current flowing through the first field effect transistor is in the negative half cycle of the feedback signal, the smaller the output current of the current source is, and the smaller the gain of the first voltage amplifier or the gain of the second voltage amplifier is; When the amplitude of the feedback signal is less than the first preset value, in the negative half cycle of the feedback signal, the first field effect transistor is in a fully on state, the current flowing through the first field effect transistor is constant, the output current of the current source is also constant, and the gain of the first voltage amplifier or the gain of the second voltage amplifier is also constant.

10. The crystal oscillator starting circuit according to claim 9, characterized in that: The current source further includes a second field effect transistor, and the first field effect transistor and the second field effect transistor form a current mirror; When the current flowing through the first field effect transistor is smaller, the current flowing through the second field effect transistor is also smaller, and the output current of the current source is also smaller.

11. A bare chip, characterized in that: The invention comprises the crystal oscillator starting circuit according to any one of claims 1 to 10.

12. A chip, characterized in that: Comprising the bare chip of claim 11.

13. An electronic device, characterized in that: Comprising the chip as claimed in claim 12.

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