An oscillation circuit with dynamic temperature correction

Abstract

The dynamic temperature-corrected oscillation circuit provided by this invention is applicable to the field of semiconductor technology. It includes an oscillation circuit and a dynamic temperature correction circuit. The oscillation circuit includes a comparator, and the dynamic temperature correction circuit includes a temperature sensor. The temperature sensor reads the current ambient temperature, and the dynamic temperature correction circuit adjusts the temperature characteristics of the comparator's bias current based on the current ambient temperature, thereby adjusting the frequency temperature characteristics of the oscillation circuit. Through this method, the oscillation circuit operating in dynamic temperature environments can be corrected, resulting in more stable operation and wider applicability.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, and particularly relates to an oscillation circuit with dynamic temperature correction. Background Technology

[0002] In large-scale integrated circuits, clock signals are a very important component in many electronic systems. Clock signals are usually generated by oscillators. RC oscillators are the most widely used type of oscillator circuit because they are simple in structure, highly integrable, and low in cost.

[0003] However, RC oscillators are greatly affected by changes in operating voltage and temperature, have poor process correlation, and are relatively inaccurate, with errors generally ranging from 2% to 10%.

[0004] The performance of the oscillator plays a crucial role in the overall system performance. With increasingly stringent requirements for clock frequency accuracy and temperature coefficient, traditional RC oscillators can no longer meet the system's needs. Summary of the Invention

[0005] The purpose of this invention is to provide a dynamic temperature-corrected oscillator circuit, which aims to solve the problem that the existing technology cannot provide a dynamic temperature-corrected oscillator circuit that can correct the clock frequency in a dynamic temperature environment, resulting in a large impact of temperature changes on the clock frequency and a poor user experience.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A dynamic temperature-corrected oscillation circuit is provided, comprising an oscillation circuit and a dynamic temperature correction circuit. The oscillation circuit includes a comparator, and the dynamic temperature correction circuit includes a temperature sensor. The current ambient temperature is read by the temperature sensor, and the dynamic temperature correction circuit adjusts the temperature characteristics of the bias current of the comparator according to the current ambient temperature, thereby adjusting the frequency temperature characteristics of the oscillation circuit.

[0008] In one embodiment of the dynamic temperature correction oscillation circuit of the present invention, when the current ambient temperature is within a threshold window, the dynamic temperature correction circuit determines a reference check code based on the current ambient temperature and the current clock frequency; when the current ambient temperature is outside the threshold window, it determines a current check code based on the current ambient temperature and the current clock frequency; and adjusts the temperature characteristics of the comparator's bias current based on the reference check code and the current check code, thereby adjusting the frequency-temperature characteristics of the oscillation circuit.

[0009] In one embodiment of the dynamic temperature correction oscillation circuit of the present invention, the dynamic temperature correction circuit further includes: a quantizer, which is used to compare a reference check code and a current check code to generate a temperature correction code; and a correction circuit, which is used to adjust the temperature characteristics of the bias current of the comparator according to the temperature correction code, thereby adjusting the frequency temperature characteristics of the oscillation circuit.

[0010] In one embodiment, the dynamic temperature correction oscillation circuit of the present invention further includes: an integrator; a clock control circuit connected to the integrator; and a window detector connected to the quantizer and the clock control circuit. When the window detector detects that the current ambient temperature is within a threshold window, it enables the clock control circuit, which provides the current clock signal of the oscillation circuit to the integrator. The integrator integrates a specified voltage for a preset clock period based on the clock signal to obtain a reference check code. When the window detector detects that the current ambient temperature is outside the threshold window, it enables the quantizer and the clock control circuit. The clock control circuit provides the current clock signal of the oscillation circuit to the integrator, which integrates a specified voltage for a preset clock period based on the clock signal to obtain a current check code.

[0011] In one embodiment of the dynamic temperature correction oscillation circuit of the present invention, when the window detector detects that the current ambient temperature is again within the threshold window, it controls the clock control circuit to disable the integrator and turn off the quantizer.

[0012] In one embodiment, the dynamic temperature correction oscillation circuit of the present invention further includes: an analog-to-digital converter (ADC) connected to an integrator, the ADC being used to convert the voltage value integrated by the integrator into a reference check code or a current check code; a first memory connected to the ADC and a quantizer, the first memory being used to store the reference check code; and a second memory connected to the ADC and a quantizer, the second memory being used to store the current check code.

[0013] In one embodiment of the dynamic temperature correction oscillation circuit of the present invention, the correction circuit includes a microprocessor and multiple field-effect transistors (FETs). The multiple FETs are all connected to the microprocessor, and the microprocessor is connected to a quantizer. The microprocessor is used to select the FETs according to the temperature correction code to adjust the temperature characteristics of the comparator's bias current.

[0014] In one embodiment of the dynamic temperature correction oscillation circuit of the present invention, the oscillation circuit includes an oscillation capacitor circuit, and the lower stage of the capacitor circuit is connected to a compensation circuit for compensating the temperature characteristics of the clock frequency.

[0015] In one embodiment of the dynamic temperature correction oscillation circuit of the present invention, the oscillation circuit further includes a comparator and a voltage regulator circuit. The output terminal of the voltage regulator circuit is connected to a first current mirror circuit, which is also connected to the non-inverting input terminal of the comparator. The non-inverting input terminal of the comparator is also connected to a pull-down resistor. The output terminal of the voltage regulator circuit is connected to a second current mirror circuit, which is also connected to the input terminal of a capacitor circuit. The inverting input terminal of the voltage comparator is also connected to the input terminal of the capacitor circuit. The output terminal of the capacitor circuit is connected to a compensation circuit, and the output terminal of the compensation circuit is grounded.

[0016] In one embodiment of the dynamic temperature correction oscillation circuit of the present invention, the output terminal of the comparator is connected to a logic controller, and the input terminal of the capacitor circuit and the output terminal of the compensation circuit are connected in parallel with a charging and discharging electronic switch, which is controlled by the logic controller. Both the capacitor circuit and the compensation circuit are connected to an external control circuit. The capacitor circuit includes multiple capacitors and multiple electronic switches. By controlling the on and off of the multiple electronic switches, the number of capacitors connected in parallel can be controlled to adjust the capacitance value of the capacitor circuit. The compensation circuit includes multiple field-effect transistors with different resistance values. By selecting field-effect transistors with different resistance values, the temperature characteristics of the clock frequency can be accurately compensated.

[0017] The present invention provides a dynamic temperature-corrected oscillation circuit, comprising an oscillation circuit and a dynamic temperature correction circuit. The oscillation circuit includes a comparator, and the dynamic temperature correction circuit includes a temperature sensor. The temperature sensor reads the current ambient temperature, and the dynamic temperature correction circuit adjusts the temperature characteristics of the comparator's bias current based on the current ambient temperature, thereby adjusting the frequency-temperature characteristics of the oscillation circuit. This method enables correction of the oscillation circuit operating in dynamic temperature environments, resulting in more stable operation and wider applicability. Attached Figure Description

[0018] Figure 1 This is a structural block diagram of the dynamic temperature correction oscillation circuit provided in Embodiment 1 of the present invention;

[0019] Figure 2 This is a schematic diagram of the reference check code storage process of the dynamic temperature correction oscillation circuit provided in Embodiment 2 of the present invention;

[0020] Figure 3 This is a schematic diagram of the dynamic temperature correction process of the oscillation circuit provided in Embodiment 2 of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] The specific implementation of the present invention will be described in detail below with reference to specific embodiments:

[0023] Example 1:

[0024] Figure 1 The structure of the dynamic temperature correction oscillation circuit provided in Embodiment 1 of the present invention is shown. For ease of explanation, only the parts related to the embodiments of the present invention are shown, and are described in detail below:

[0025] In this embodiment of the invention, the dynamic temperature-corrected oscillation circuit includes an oscillation circuit and a dynamic temperature correction circuit. The oscillation circuit includes a capacitor circuit K that generates an oscillation current. The lower stage of the capacitor circuit K is connected to a compensation circuit M that compensates for the temperature characteristics of the clock frequency. The dynamic temperature correction circuit includes a temperature sensor (TempSensor). The current ambient temperature is read by the temperature sensor (TempSensor), and the temperature characteristics of the clock frequency are corrected accordingly. The dynamic temperature-corrected oscillation circuit provided by this invention includes an oscillation circuit and a dynamic temperature correction circuit. The oscillation circuit includes a capacitor circuit K. The lower stage of the capacitor circuit K is connected to the compensation circuit M that compensates for the temperature characteristics of the clock frequency. The compensation circuit M causes the charging range of the capacitor circuit K to change with temperature changes, thereby affecting the charging time. This is to compensate for the logic gate delay problem caused by temperature changes by utilizing the change in charging time caused by the capacitor circuit. Furthermore, the current ambient temperature is read by the temperature sensor (TempSensor) in the dynamic temperature correction circuit, and the temperature characteristics of the clock frequency are corrected according to the current ambient temperature, improving the stability of the clock frequency with temperature changes. This achieves correction of the oscillation circuit operating in a dynamic temperature environment, making the oscillation circuit more stable and more widely applicable.

[0026] like Figure 1 As shown, the oscillation circuit also includes a comparator COMP and a voltage regulator LDO. The output of the voltage regulator LDO is connected to a first current mirror circuit (not shown in the figure), which is also connected to the non-inverting input of the comparator COMP. The non-inverting input of the comparator COMP is also connected to a pull-down resistor R. The output of the voltage regulator LDO is connected to a second current mirror circuit (not shown in the figure), which is also connected to the input of the capacitor circuit K. The inverting input of the voltage comparator COMP is also connected to the input of the capacitor circuit K. The output of the capacitor circuit K is connected to a compensation circuit M, and the output of the compensation circuit M is grounded, further improving the accuracy of the clock frequency.

[0027] like Figure 1As shown, the output of comparator COMP is connected to a logic controller LogicControl. The input of capacitor circuit K and the output of compensation circuit M are connected in parallel to a charging / discharging electronic switch S, which is controlled by the logic controller LogicControl. Both capacitor circuit K and compensation circuit M are connected to an external control circuit. Capacitor circuit K includes multiple capacitors (not shown in the figure) and multiple electronic switches (not shown in the figure). By controlling the on / off state of multiple electronic switches, the number of capacitors connected in parallel can be controlled, thereby adjusting the capacitance value of the capacitor circuit. Compensation circuit M includes multiple field-effect transistors (not shown in the figure) with different resistance values. By selecting field-effect transistors with different resistance values, precise compensation of the temperature characteristics of the clock frequency can be achieved.

[0028] like Figure 1 As shown, the dynamic temperature correction circuit also includes a temperature threshold window detector (TempWindowDetect) connected to the temperature sensor (TempSensor). The temperature threshold window detector (TempWindowDetect) is connected to a clock control circuit (ClockControl) and a quantizer. The logic controller (LogicControl) is also connected to the clock control circuit (ClockControl). The clock control circuit (ClockControl) is also connected to an integrator (Integrator). The integrator is connected to an analog-to-digital converter (ADC). The ADC is connected to a first memory (Memory1) and a second memory (Memory2). Both the first memory (Memory1) and the second memory (Memory2) are connected to the quantizer. The quantizer is also connected to a correction circuit (N) for correcting the temperature characteristics of the bias current of the comparator (COMP).

[0029] like Figure 1 As shown, the correction circuit N includes a microprocessor (not shown in the figure) and multiple field-effect transistors (not shown in the figure). The multiple field-effect transistors are all connected to the microprocessor, and the microprocessor is connected to the quantizer.

[0030] Example 2:

[0031] Figure 1 The structure of the dynamic temperature correction oscillation circuit provided in Embodiment 2 of the present invention is shown. For ease of explanation, only the parts related to the embodiments of the present invention are shown, and are described in detail below:

[0032] In this embodiment of the invention, the oscillation circuit includes a voltage regulator circuit LDO, which regulates the power supply voltage VDD and outputs VLDO to provide a stable operating voltage for the core components of the oscillation circuit, eliminating the influence of the power supply voltage on the clock frequency. Current I1 generates a reference voltage VREF across the pull-down resistor R, which is connected to the positive input of the comparator COMP. The reference voltage VREF = I1 * R. Current I2 provides charging / discharging current to the capacitor circuit K, which is connected to the negative input of the comparator COMP and compared with the reference voltage VREF. Based on the output of the comparator COMP, the logic controller LogicControl controls the on / off state of the charging / discharging electronic switch S of the capacitor circuit K to generate a clock signal.

[0033] According to formula (1): Obtain the clock frequency, where C total Let f be the capacitance output of capacitor circuit K, and f be the clock frequency. Clock frequency is often easily affected by process variations. This invention uses an external control circuit to control the on / off state of multiple electronic switches in capacitor circuit K, thereby precisely controlling the number of capacitors connected in parallel to control the total output capacitance, which is the C in formula (1). total Adjustments are made by calibrating the clock frequency at the chip manufacturing stage to ensure the accuracy of the clock frequency and eliminate the impact of process variations on the clock frequency.

[0034] A compensation circuit 2 is connected below capacitor circuit 1 to perform the first compensation for the temperature characteristics of the clock frequency. The channel resistance of the field-effect transistor in compensation circuit 2 changes with temperature. This changing channel resistance alters the capacitor charging range, causing a change in charging time. This change in charging time is used to compensate for the logic gate delay caused by temperature variations. An external control circuit selects a field-effect transistor with a suitable channel resistance from compensation circuit M and connects it to the oscillation circuit for temperature compensation. This scheme performs the first adjustment of the clock frequency's temperature characteristics, achieving an error range of ±2%. Compared to traditional oscillators, this largely eliminates the impact of temperature changes on the clock frequency.

[0035] Based on the initial correction of the clock frequency temperature characteristics, this invention further incorporates dynamic temperature correction technology for a second adjustment. Its complete structure includes: a temperature sensor (TempSensor) detects the current ambient temperature and sends the detected temperature value to a temperature threshold window detector (TempWindowDetect). When the temperature threshold window detector detects that the corresponding temperature value falls within the threshold window, the clock control circuit (ClockControl) activates the integrator and the quantizer. The integrator begins integrating a specified voltage signal. The integrated output voltage of the integrator is converted by an analog-to-digital converter (ADC). The ADC outputs a current ambient temperature check code and a reference check code, which are compared by the quantizer to generate a set of temperature correction codes to adjust the temperature characteristics of the oscillation circuit frequency.

[0036] The aforementioned oscillation circuit was tested at room temperature (T) before leaving the factory. R Clock frequency correction will be performed at ℃, and this clock frequency f will be used. R Defined as the room temperature reference correction frequency.

[0037] The basic principle of dynamic temperature correction technology is to detect the current ambient temperature using a temperature sensor (TempSensor) and send this temperature value to a temperature threshold window detector (TempWindowDetect). When the temperature threshold window detector (TempWindowDetect) detects that the corresponding temperature value falls within the room temperature (TR±ΔT) threshold window, it initiates reference check code storage. Reference check code storage is activated by a clock control circuit (ClockControl) to integrate a specified voltage within a defined clock count length. The integration result is converted into a corresponding digital code by an analog-to-digital converter (ADC) and stored in the system memory (first memory Memory1) as the reference check code (D). ref .

[0038] As the ambient temperature changes and drifts, when the temperature threshold window detector (TempWindowDetect) detects that the ambient temperature value falls within the threshold window TN±ΔT of other non-room temperature environments (the entire temperature range is divided into TN=TR+2K*ΔT, K=0, ±1, ±2……), the corresponding oscillation frequency temperature correction is initiated. This oscillation frequency temperature correction also activates the integrator via the clock control circuit (ClockControl), integrating the same specified voltage within the same specified clock count length. The integration result is converted into a corresponding digital code by the analog-to-digital converter (ADC) and recorded in the system memory (secondary memory Memory2), as D. ENV D ENV This corresponds to the checksum of the current ambient temperature. (D) ENV And the previous benchmark check code D ref A set of temperature correction codes (i.e., the second temperature correction code Tt2) is generated by comparing the results using a quantizer. <n-1:0>To adjust the frequency-temperature characteristics of the oscillator circuit. Because the clock counting length is related to the frequency of the oscillator circuit, when the frequency f of the oscillator circuit... N Compared to the room temperature reference correction frequency f R If the value is too large or too small, the corresponding clock counting length will shorten or lengthen, and the integrator's output voltage will decrease or increase accordingly. This feedback will then adjust the temperature correction code to change negatively or positively, ultimately affecting the frequency f of the oscillation circuit. N Stabilized at the reference room temperature correction frequency f R Nearby, reducing the temperature offset of the oscillation circuit further eliminates the influence of temperature changes on the clock frequency.

[0039] like Figure 2 The schematic diagram of the reference check code storage process provided by the present invention shows that, initially, the integrator is in a reset state. After each integration conversion, the integrator is reset again via the RST signal. The temperature sensor TempSensor detects the current ambient temperature and sends the temperature value to the temperature threshold window detector TempWindowDetect. When the temperature threshold window detector TempWindowDetect detects that the corresponding temperature value falls within the room temperature TR±ΔT threshold window, the reference check code storage is started. The reference check code storage activates the integrator by controlling the clock signal in the oscillation circuit through the clock control circuit ClockControl. The clock control circuit ClockControl provides a clock signal to the integrator, which begins to integrate the Vin signal. After integrating the Vin signal for N clock cycles, the integrator obtains the voltage Vo1. The voltage Vo1 is converted by the analog-to-digital converter ADC to obtain the reference check code D. ref The verification code D ref After the conversion is completed and the data is saved to the first memory (Memory1), the integrator is reset. At this point, the second temperature correction code (Tt2) is generated. <n-1:0>Keep the default value.

[0040] like Figure 3 The schematic diagram of the dynamic temperature correction process provided by this invention shows that as the ambient temperature changes and drifts, when the temperature threshold window detector TempWindowDetect detects that the ambient temperature value still falls within the room temperature temperature TR±ΔT threshold window, the temperature threshold window detector TempWindowDetect controls the clock control circuit ClockControl to make the integrator stop working and simultaneously turn off the quantizer. At this time, the second temperature correction code Tt2 is generated. <n-1:0>The default values ​​are maintained. When the temperature threshold window detector (TempWindowDetect) detects that the ambient temperature value falls within the threshold window TN±ΔT of other non-room temperature environments, the corresponding oscillation frequency temperature correction is initiated. This oscillation frequency temperature correction also activates the integrator via the clock control circuit (ClockControl). The integrator then restarts integration on the same Vin signal, integrating it for N clock cycles. The integrated voltage Vo2 is then converted by the analog-to-digital converter (ADC) to obtain the checksum D. ENV D ENV Save it to the second memory Memory2, and then save the reference check code D from the first memory Memory1. ref Read out the verification code D. ENV and reference check code D ref The comparison is performed using a quantizer to generate a set of temperature correction codes (i.e., the second temperature correction code Tt2). <n-1:0>To control the correction circuit N, a suitable field-effect transistor is selected to adjust the temperature characteristic of the bias current I of the comparator COMP, so that the frequency f of the oscillation circuit is adjusted. N Stabilized at room temperature reference correction frequency f R nearby.

[0041] Using the same correction method as described above, and through the second temperature correction code Tt2 <n-1:0>The temperature characteristics of the comparator COMP bias current I are dynamically adjusted so that the frequency f of the oscillation circuit can be maintained over a wide temperature range. N All are stable at the room temperature reference correction frequency f R Nearby. The temperature curve after clock frequency compensation is dynamically fitted to a new temperature curve, realizing dynamic correction of the temperature characteristics of the clock frequency, and improving the stability of the clock frequency with temperature change to within ±0.5% error range.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dynamic temperature correction oscillator circuit comprising an oscillator circuit and a dynamic temperature correction circuit, characterized in that, The oscillation circuit includes a comparator, and the dynamic temperature correction circuit includes a temperature sensor, a quantizer, and a correction circuit. The current ambient temperature is read through the temperature sensor, and the dynamic temperature correction circuit adjusts the temperature characteristics of the bias current of the comparator according to the current ambient temperature, thereby adjusting the frequency temperature characteristics of the oscillation circuit. When the current ambient temperature is within the threshold window, the dynamic temperature correction circuit determines the reference check code based on the current ambient temperature and the current clock frequency; when the current ambient temperature is outside the threshold window, it determines the current check code based on the current ambient temperature and the current clock frequency. The quantizer is used to compare the reference check code and the current check code to generate a temperature correction code; The correction circuit is used to adjust the temperature characteristics of the comparator's bias current according to the temperature correction code, thereby adjusting the frequency temperature characteristics of the oscillation circuit.

2. The dynamic temperature-corrected oscillation circuit as described in claim 1, characterized in that, The dynamic temperature correction circuit also includes: Integrator; A clock control circuit, which is connected to the integrator; A window detector, which is connected to the quantizer and the clock control circuit; Specifically, when the window detector detects that the current ambient temperature is within a threshold window, it enables the clock control circuit. The clock control circuit provides the current clock signal of the oscillation circuit to the integrator. The integrator integrates a specified voltage for a preset clock period based on the clock signal to obtain the reference check code. When the window detector detects that the current ambient temperature is outside the threshold window, it enables the quantizer and the clock control circuit. The clock control circuit provides the current clock signal of the oscillation circuit to the integrator. The integrator integrates a specified voltage for a preset clock period based on the clock signal to obtain the current check code.

3. The dynamic temperature-corrected oscillation circuit as described in claim 2, characterized in that, When the window detector detects that the current ambient temperature is again within the threshold window, it controls the clock control circuit to disable the integrator and turn off the quantizer.

4. The dynamic temperature-corrected oscillation circuit as described in claim 2, characterized in that, The dynamic temperature correction circuit also includes: An analog-to-digital converter, connected to the integrator, is used to convert the voltage value obtained by the integrator into the reference check code or the current check code; A first memory, connected to the analog-to-digital converter and the quantizer, is used to store the reference check code; A second memory, connected to the analog-to-digital converter and the quantizer, is used to store the current checksum.

5. The dynamic temperature-corrected oscillation circuit as described in claim 1, characterized in that, The correction circuit includes a microprocessor and multiple field-effect transistors (FETs). The FETs are all connected to the microprocessor, which is connected to the quantizer. The microprocessor is used to select the FETs according to the temperature correction code to adjust the temperature characteristics of the comparator's bias current.

6. The dynamic temperature-corrected oscillation circuit as described in claim 1, characterized in that, The oscillation circuit includes a capacitor circuit for starting oscillation, and the lower stage of the capacitor circuit is connected to a compensation circuit that compensates for the temperature characteristics of the clock frequency.

7. The dynamic temperature-corrected oscillation circuit as described in claim 6, characterized in that, The oscillation circuit further includes a comparator and a voltage regulator circuit. The output terminal of the voltage regulator circuit is connected to a first current mirror circuit, which is also connected to the non-inverting input terminal of the comparator. The non-inverting input terminal of the comparator is also connected to a pull-down resistor. The output terminal of the voltage regulator circuit is connected to a second current mirror circuit, which is also connected to the input terminal of the capacitor circuit. The inverting input terminal of the comparator is also connected to the input terminal of the capacitor circuit. The output terminal of the capacitor circuit is connected to the compensation circuit, and the output terminal of the compensation circuit is grounded.

8. The oscillation circuit with dynamic temperature correction as described in claim 7, characterized in that, The output of the comparator is connected to a logic controller. A charge / discharge electronic switch is connected in parallel to the input of the capacitor circuit and the output of the compensation circuit. The charge / discharge electronic switch is controlled by the logic controller. Both the capacitor circuit and the compensation circuit are connected to an external control circuit. The capacitor circuit includes multiple capacitors and multiple electronic switches. By controlling the on / off state of the multiple electronic switches, the number of capacitors connected in parallel is controlled, thereby adjusting the capacitance value of the capacitor circuit. The compensation circuit includes multiple field-effect transistors with different resistance values. By selecting field-effect transistors with different resistance values, precise compensation for the temperature characteristics of the clock frequency is achieved.

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