Circuit devices and oscillators

Abstract

A circuit arrangement and an oscillator are provided, capable of appropriately controlling the tail current flowing through a differential pair circuit that generates a temperature-compensating current. The circuit arrangement (20) includes: an oscillation circuit (30) that causes an oscillator (10) to oscillate to generate an oscillation signal; a temperature compensation circuit (40) that includes a high-order correction circuit (44) that generates a high-order compensation current based on a temperature detection voltage from a temperature detection circuit (50), a temperature compensation voltage that generates an oscillation frequency of the oscillation signal based on the high-order compensation current; and a tail current control circuit (70). The high-order correction circuit (44) includes a differential pair circuit that controls the tail current via the tail current control circuit, which generates a temperature-compensating current based on the temperature detection voltage. The tail current control circuit controls the tail current in such a way that the current value is at the inflection point temperature of the temperature compensation voltage and increases according to the temperature change from the inflection point temperature.

Description

Technical Field

[0001] This invention relates to circuit devices and oscillators, etc. Background Technology

[0002] In circuit devices that oscillate oscillators such as quartz oscillators, temperature compensation of the oscillation frequency is performed. For example, Patent Document 1 discloses a circuit device for performing such temperature compensation. For example, in the temperature compensation circuit, a temperature compensation current is generated using a differential pair circuit, and this temperature compensation current is used to perform temperature compensation of the oscillation frequency.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2023-90099 Summary of the Invention

[0006] However, no method has been proposed to appropriately control the tail current flowing into the differential pair circuit based on factors such as lowering the power supply voltage and reducing power consumption.

[0007] One aspect of this disclosure relates to a circuit arrangement comprising: an oscillation circuit that causes an oscillator to oscillate to generate an oscillation signal; a temperature compensation circuit comprising a high-order correction circuit that generates a high-order compensation current based on a temperature detection voltage from a temperature detection circuit, and a temperature compensation voltage that generates an oscillation frequency of the oscillation signal based on the high-order compensation current; and a tail current control circuit, the high-order correction circuit comprising a differential pair circuit that controls a tail current via the tail current control circuit, generating a temperature compensation current based on the temperature detection voltage, the tail current control circuit controlling the tail current such that the current value is a minimum current value at the inflection point temperature of the temperature compensation voltage, and increasing the tail current according to temperature changes from the inflection point temperature.

[0008] Furthermore, other aspects of this disclosure relate to an oscillator that includes the circuitry described above and the oscillator. Attached Figure Description

[0009] Figure 1 This is an example of the structure of the circuit device in this embodiment.

[0010] Figure 2 This is a detailed structural example of the circuit device and oscillator in this embodiment.

[0011] Figure 3 This is an example of the structure of a temperature compensation circuit.

[0012] Figure 4 This is an explanatory diagram of temperature compensation processing.

[0013] Figure 5 This is an example of the structure of a compensation circuit for a high-order correction circuit.

[0014] Figure 6 This is an explanatory diagram of the method for generating temperature compensation current.

[0015] Figure 7 This is an example of the structure of a temperature detection circuit.

[0016] Figure 8 These are other structural examples of temperature detection circuits.

[0017] Figure 9 This is an example of the structure of a temperature detection circuit and a temperature compensation circuit.

[0018] Figure 10 This is an example of the temperature characteristics of the temperature detection voltage and the reference voltage.

[0019] Figure 11 This is an example of the structure of a differential pair circuit.

[0020] Figure 12 This is an example of the temperature characteristics of the current flowing to the low-temperature side of a differential pair circuit.

[0021] Figure 13 This is an example of the temperature characteristics of the current flowing to the high-temperature side of a differential pair circuit.

[0022] Figure 14 This is an example of the temperature characteristics of the temperature detection voltage.

[0023] Figure 15 This is an example of the temperature characteristics of the current used for temperature compensation.

[0024] Figure 16 This is an example of the temperature characteristics of the current used for temperature compensation.

[0025] Figure 17 This is an example of the structure of a tail current control circuit.

[0026] Figure 18 This is an example illustrating the temperature characteristics of the tail current control circuit.

[0027] Figure 19 This is an illustration of the effect of giving the tail current temperature characteristics.

[0028] Figure 20 This is an illustration of the effect of giving the tail current temperature characteristics.

[0029] Figure 21 These are other structural examples of tail current control circuits.

[0030] Label Explanation

[0031] 4…Oscillator; 10…Reverberant; 20…Circuit device; 30…Oscillating circuit; 32…Variable capacitor circuit; 40…Temperature compensation circuit; 42…Current generation circuit; 43…First correction circuit; 44…Higher order correction circuit; 46…Current-to-voltage conversion circuit; 47…First compensation circuit; 48…Second compensation circuit; 50…Temperature detection circuit; 52…Temperature sensor; 54…Output circuit; 60…Reference voltage generation circuit; 70…Tail current control circuit; 71…First tail current control circuit; 72…Second tail current control circuit; 74…Differential section; 75…Output section; 80…Output circuit; 90…Power supply circuit; 100…Control circuit; 11 0…Non-volatile memory; DP, DPH, DPH1, DPH2, DPL, DPL1, DPL2…Differential pair circuits; IB, IBH, IBL…Tail current; ICP…Temperature compensation current; ICU…High-order compensation current; IER, ITH, IH, IL, IQ…Current; OPD, OPD1, OPD2, OPD3…Operational amplifiers; VA1, VA2…Voltage; VB, VBH, VBL, VBN…Bias voltage; VCP…Temperature compensation voltage; VR, VR0, VRC…Reference voltage; VSE…Sensor voltage; VT1, VT2…Voltage; VTS…Temperature detection voltage; VTS2…Voltage. Detailed Implementation

[0032] The following describes this embodiment. Furthermore, the embodiments described below are not intended to unduly limit the scope of the claims. Also, not all structures described in this embodiment are necessarily essential components.

[0033] 1. Circuit device

[0034] Figure 1 An example of the structure of the circuit device 20 of this embodiment is shown. The circuit device 20 of this embodiment includes an oscillation circuit 30, a temperature compensation circuit 40, and a tail current control circuit 70. Furthermore, the circuit device 20 may include a temperature detection circuit 50. Additionally, the oscillator 10 is electrically connected to the circuit device 20, and for example, the oscillator 10 and the circuit device 20 constitute an oscillator. Moreover, the circuit device 20 is not limited to... Figure 1 The structure can be transformed in various ways, such as omitting some of its constituent elements, adding other constituent elements, or replacing some of its constituent elements with other constituent elements.

[0035] The oscillator 10 is a component that generates mechanical vibration through an electrical signal. The oscillator 10 can be implemented, for example, using a quartz resonator or similar vibrating plate. For instance, the oscillator 10 can be implemented using a quartz resonator that undergoes thickness shear vibration with an AT cut or SC cut, a tuning fork type quartz resonator, or a double tuning fork type quartz resonator. For example, the oscillator 10 can be an oscillator built into a temperature-compensated quartz oscillator (TCXO) without a thermostatic bath, or an oscillator built into a thermostatic bath type quartz oscillator (OCXO) with a thermostatic bath. Furthermore, the oscillator 10 of this embodiment can also be implemented using various vibrating plates, such as those other than thickness shear vibration type, tuning fork type, or double tuning fork type, or piezoelectric resonators made of materials other than quartz. For example, the oscillator 10 can also be a SAW (Surface Acoustic Wave) resonator or a MEMS (Micro Electro Mechanical Systems) oscillator using a silicon oscillator formed on a silicon substrate.

[0036] Circuit device 20 is an integrated circuit device called an IC (Integrated Circuit). For example, circuit device 20 is an IC manufactured using semiconductor processes, which is a semiconductor chip on a semiconductor substrate with circuit elements formed thereon. Circuit device 20 operates based on a power supply voltage supplied from an external source.

[0037] The oscillation circuit 30 is a circuit that causes the oscillator 10 to oscillate. For example, the oscillation circuit 30 generates an oscillation signal by causing the oscillator 10 to oscillate. The oscillation signal is, for example, an oscillation clock signal. For example, the oscillation circuit 30 can be implemented using passive components such as an oscillation drive circuit, a capacitor, and a resistor that are electrically connected to one end and the other end of the oscillator 10. The drive circuit can be implemented, for example, using a CMOS inverter circuit or a bipolar transistor. The drive circuit is the core circuit of the oscillation circuit 30, and it drives the oscillator 10 with voltage or current, thereby causing the oscillator 10 to oscillate. As the oscillation circuit 30, various types of oscillation circuits, such as inverter type, Pierce type, Colpitts type, or Hartley type, can be used. In addition, the connection in this embodiment is an electrical connection. An electrical connection refers to a connection that can transmit electrical signals, and is a connection that can transmit information based on electrical signals. An electrical connection can also be a connection via passive components, etc.

[0038] The temperature detection circuit 50 is a sensor circuit for detecting temperature. Specifically, the temperature detection circuit 50 outputs a temperature-dependent voltage, VTS, which varies according to the ambient temperature. For example, the temperature detection circuit 50 generates the temperature detection voltage VTS as a temperature detection signal using temperature-dependent circuit elements. Specifically, the temperature detection circuit 50 outputs a temperature detection voltage VTS that varies with temperature, for example, by utilizing the temperature dependence of the forward voltage of a PN junction. Alternatively, a variation of the temperature detection circuit 50 can be implemented using a digital temperature detection circuit. In this case, the temperature detection voltage VTS is generated by performing a D / A conversion on the temperature detection data.

[0039] The temperature compensation circuit 40 performs temperature compensation for the oscillation frequency of the oscillation circuit 30. For example, based on the temperature detection voltage VTS from the temperature detection circuit 50, the temperature compensation circuit 40 outputs a temperature compensation voltage VCP for the oscillation frequency of the oscillation signal to the oscillation circuit 30. Temperature compensation is, for example, a process that suppresses and compensates for fluctuations in the oscillation frequency caused by temperature variations. That is, the temperature compensation circuit 40 performs temperature compensation for the oscillation frequency of the oscillation circuit 30 so that the oscillation frequency remains constant even in the presence of temperature variations. Alternatively, a variation can be implemented where the temperature compensation data obtained by A / D conversion of the temperature compensation voltage VCP is used to digitally adjust the oscillation frequency in the variable capacitor circuit of the oscillation circuit 30.

[0040] Furthermore, the temperature compensation circuit 40 includes a higher-order correction circuit 44, which generates a higher-order compensation current based on the temperature detection voltage VTS from the temperature detection circuit 50. The temperature compensation circuit 40 generates a temperature compensation voltage VCP based on this higher-order compensation current, which is the oscillation frequency of the oscillation signal. For example, when approximating the temperature compensation voltage VCP using a higher-order polynomial, the higher-order correction circuit 44 generates a higher-order compensation current corresponding to the higher-order term of the polynomial. The temperature compensation circuit 40 generates the temperature compensation voltage VCP by performing a current-to-voltage conversion on the temperature compensation current, which is obtained by adding the first-order compensation current corresponding to the first-order term of the polynomial and the higher-order compensation current.

[0041] Furthermore, the higher-order correction circuit 44 includes a differential pair circuit DP. The differential pair circuit DP controls the tail current via the tail current control circuit 70, generating a temperature compensation current based on the temperature detection voltage VTS. The higher-order compensation current is generated based on the temperature compensation current generated by the differential pair circuit DP.

[0042] Thus, the tail current control circuit 70 controls the tail current flowing to the differential pair circuit DP. The tail current is also called the bias current. For example, the differential pair circuit DP has a first transistor and a second transistor constituting the differential pair, and a transistor for a current source to allow current to flow to the first transistor and the second transistor. The base or gate of the first transistor of the differential pair is controlled, for example, by an input temperature detection voltage VTS, and the base or gate of the second transistor of the differential pair is controlled, for example, by an input reference voltage. The tail current control circuit 70 controls the tail current flowing to the transistor of the current source. For example, the tail current is defined as the current obtained by adding the current flowing to the first transistor of the differential pair and the current flowing to the second transistor. For example, the tail current control circuit 70 controls the tail current by outputting a bias voltage VB, used to allow the tail current to flow to the transistor of the current source, to the gate or base of the transistor of the current source.

[0043] Furthermore, in this embodiment, the tail current control circuit 70 controls the tail current to be at its minimum value at the inflection point temperature of the temperature compensation voltage VCP, and to increase the tail current according to temperature changes from the inflection point temperature. The inflection point temperature is, for example, a typical temperature, such as 25°C. For example, the temperature compensation voltage VCP is set to become, for example, the reference voltage VRC described later at the inflection point temperature. Additionally, the higher-order compensation current is set to a minimum current value, such as zero, at the inflection point temperature. Furthermore, the temperature compensation voltage VCP varies with respect to temperature changes relative to the reference voltage VRC, for example, changing towards the positive side or towards the negative side relative to the reference voltage VRC depending on the temperature change.

[0044] The tail current control circuit 70 controls the tail current of the differential pair circuit DP, such that the tail current becomes the minimum current value at the inflection point temperature. The minimum current value is, for example, zero, but it can also be a current value greater than zero. Furthermore, even if the tail current control circuit 70 is set to a minimum current value, such as zero, at the inflection point temperature, a current greater than the minimum current value can still flow to the transistor of the current source in the differential pair circuit through the leakage current of the transistor.

[0045] Furthermore, the tail current control circuit 70 controls the tail current in such a way that the current value increases according to the temperature change from the inflection point temperature. For example, the tail current control circuit 70 controls the tail current of the differential pair circuit DP in such a way that the tail current increases from the minimum current value as the temperature decreases from the inflection point temperature. Alternatively, the tail current control circuit 70 controls the tail current of the differential pair circuit DP in such a way that the tail current increases from the minimum current value as the temperature increases from the inflection point temperature.

[0046] Thus, in this embodiment, the tail current of the differential pair circuit DP flowing to the higher-order correction circuit 44 is controlled to be at its minimum value at the inflection point temperature. Therefore, the higher-order compensation current generated by the current in the differential pair circuit DP can be set to a minimum value, such as zero, at the inflection point temperature, making inflection point adjustment easier. Furthermore, the tail current of the differential pair circuit DP flowing to the higher-order correction circuit 44 is controlled so that its value increases according to temperature changes. Therefore, for example, even if the gain of the temperature characteristic of the temperature detection voltage VTS of the temperature detection circuit 50 decreases due to factors such as a lower power supply voltage of the circuit device 20, the higher-order correction circuit 44 can appropriately generate a higher-order compensation current by giving the tail current a temperature characteristic. Moreover, by controlling the tail current so that its value is at its minimum at the inflection point temperature and increases according to temperature changes, useless current flowing to the differential pair circuit DP can be reduced, enabling low power consumption of the circuit device 20.

[0047] Figure 2 A detailed structural example of the circuit device 20 and oscillator 4 in this embodiment is shown. Figure 2 In the circuit 20, in addition to the oscillation circuit 30, temperature compensation circuit 40, and tail current control circuit 70, it also includes a temperature detection circuit 50, a reference voltage generation circuit 60, an output circuit 80, a power supply circuit 90, a control circuit 100, and a non-volatile memory 110. Furthermore, the oscillator 4 includes a vibrator 10 and the circuit 20, with the vibrator 10 electrically connected to the circuit 20. For example, the vibrator 10 and the circuit 20 are electrically connected using internal wiring, bonding wires, or metal bumps in a package that houses the vibrator 10 and the circuit 20. Additionally, the circuit 20 and the oscillator 4 are not limited to... Figure 2 The structure can be transformed in various ways, such as omitting some of its constituent elements, adding other constituent elements, or replacing some of its constituent elements with other constituent elements.

[0048] Furthermore, the circuit device 20 includes pads PVDD, PGND, PX1, PX2, and PCK. The pads are terminals of the circuit device 20, which serves as a semiconductor chip. For example, in the pad region, a metal layer is exposed from a passivation film that serves as an insulating layer, and this exposed metal layer constitutes the pads serving as terminals of the circuit device 20. Pads PVDD and PGND are power pads and ground pads, respectively. The power supply voltage VDD from an external power supply device is supplied to pad PVDD. Pad PGND is a pad supplied as ground voltage GND. Ground voltage is, for example, ground potential. In this embodiment, GND is appropriately referred to as VSS. For example, VDD corresponds to the high-potential side power supply, and VSS as GND corresponds to the low-potential side power supply. Pads PX1 and PX2 are pads for connecting the oscillator 10. Pad PCK is a pad for outputting the clock signal CK. Pads PVDD, PGND, and PCK are electrically connected to terminals TVDD, TGND, and TCK, which are external terminals for external connection to the oscillator 4. For example, these pads and terminals are electrically connected using internal wiring, bonding wires, or metal bumps within the package. Alternatively, terminals and pads can be provided to receive an external control voltage, which allows an external system to control the oscillation frequency.

[0049] The oscillation circuit 30 is electrically connected to the oscillator 10 via pads PX1 and PX2. Pads PX1 and PX2 are pads for connecting the oscillator. The oscillation drive circuit of the oscillation circuit 30 is disposed between pads PX1 and PX2. The oscillation circuit 30 includes a variable capacitor circuit 32. The variable capacitor circuit 32 is, for example, a circuit that changes the capacitance of at least one of the ends of the oscillator 10, and the oscillation frequency of the oscillation circuit 30 can be adjusted by adjusting the capacitance of the variable capacitor circuit 32. That is, by electrically connecting the variable capacitor circuit 32 to at least one of pads PX1 and PX2, the load capacitance of the oscillation circuit 30 can be variably adjusted. The variable capacitor circuit 32 can be implemented, for example, by a variable capacitor element such as a varactor diode. For example, the variable capacitor circuit 32 is composed of at least one variable capacitor element.

[0050] The temperature compensation circuit 40 performs analog temperature compensation, for example, based on polynomial approximation. For instance, when the temperature compensation voltage VCP is approximated using a polynomial to compensate for the frequency-temperature characteristics of the oscillator 10, the temperature compensation circuit 40 performs analog temperature compensation based on the coefficient information of the polynomial. Analog temperature compensation is achieved, for example, through addition processing of analog signals such as current and voltage signals. For example, when the temperature compensation voltage VCP is approximated using a high-order polynomial, the 0th-order coefficient, 1st-order coefficient, and high-order coefficients of the polynomial are stored as 0th-order correction data, 1st-order correction data, and high-order correction data, respectively, in a storage unit implemented, for example, a non-volatile memory 110. High-order coefficients are, for example, coefficients of orders greater than 1st, and high-order correction data are correction data corresponding to the high-order coefficients. For example, when the temperature compensation voltage VCP is approximated using a 3rd-order polynomial, the 0th-order coefficient, 1st-order coefficient, 2nd-order coefficient, and 3rd-order coefficients of the polynomial are stored as 0th-order correction data, 1st-order correction data, 2nd-order correction data, and 3rd-order correction data, respectively, in the storage unit. Furthermore, the temperature compensation circuit 40 performs temperature compensation based on correction data from the 0th to the 3rd order. In this case, the 2nd order correction data can also be omitted, and temperature compensation based on the 2nd order correction data can be performed. Additionally, for example, when approximating the temperature compensation voltage VCP using a 5th order polynomial, the 0th, 1st, 2nd, 3rd, 4th, and 5th order coefficients of the polynomial are stored in the storage unit as 0th order correction data, 1st order correction data, 2nd order correction data, 3rd order correction data, 4th order correction data, and 5th order correction data, respectively. The temperature compensation circuit 40 performs temperature compensation based on the 0th to the 5th order correction data. In this case, the 2nd or 4th order correction data can also be omitted, and temperature compensation based on the 2nd or 4th order correction data can be performed. Furthermore, the degree of the polynomial approximation is arbitrary; for example, a polynomial approximation with a degree greater than 5 can be performed.

[0051] A reference voltage generation circuit 60 for temperature compensation generates a reference voltage for temperature compensation and outputs it to a temperature compensation circuit 40. The reference voltage generated by the reference voltage generation circuit 60 is the reference voltage VRC (described later) or the reference voltage input to one of the first and second transistors of the differential pair circuit. In this case, a temperature detection voltage VTS is input to the other transistor. For example, the reference voltage generation circuit 60 has a reference circuit that generates a voltage VRF, such as the BGR voltage. BGR is an abbreviation for bandgap reference. Furthermore, the reference voltage generation circuit 60 generates the reference voltage based on the voltage VRF generated by the reference circuit. In this case, the reference voltage generation circuit 60 may have a regulator that generates the reference voltage based on the voltage generated by the regulator based on the voltage VRF. For example, the regulator adjusts the power supply voltage VDD based on the voltage VRF, and the reference voltage generation circuit 60 generates the reference voltage based on the voltage generated by the regulator. For example, the reference voltage generation circuit 60 uses the voltage VRF generated by the reference circuit or the voltage generated by the regulator based on the voltage VRF as a reference power supply voltage to generate the reference voltage. For example, the reference voltage generation circuit 60 generates a reference voltage by dividing the reference power supply voltage using a voltage generation circuit composed of resistor circuits, etc. In this case, multiple reference voltages can be generated by making the resistor division ratios in the voltage generation circuit different, and supplied to the temperature compensation circuit 40.

[0052] The power supply circuit 90 is supplied with, for example, an external power supply voltage VDD and a ground voltage GND, to supply various power supply voltages for the internal circuits of the circuit device 20. For example, the power supply circuit 90 is supplied with a power supply voltage VDD from the pad PVDD and a ground voltage VSS from the pad PGND as GND, to supply various power supply voltages for the internal circuits of the circuit device 20. For example, the power supply circuit 90 supplies various circuits of the circuit device 20, such as the power supply voltage isotropic oscillation circuit 30, the temperature compensation circuit 40, the temperature detection circuit 50, the reference voltage generation circuit 60, and the tail current control circuit 70, which are obtained by regulating the power supply voltage.

[0053] The control circuit 100 is a circuit that performs various control processes, such as those implemented by logic circuits. For example, the control circuit 100 controls the circuit device 20 as a whole, or controls the sequence of actions of the circuit device 20. Furthermore, the control circuit 100 performs various processes for controlling the oscillation circuit 30, or controls the temperature compensation circuit 40, temperature detection circuit 50, reference voltage generation circuit 60, tail current control circuit 70, output circuit 80, or power supply circuit 90, or controls the reading and writing of information from the non-volatile memory 110. The control circuit 100 can be implemented, for example, using an ASIC (Application Specific Integrated Circuit) circuit based on automatic configuration routing such as a gate array.

[0054] The non-volatile memory 110 is a memory that retains information even when no power is supplied. For example, the non-volatile memory 110 is a memory that can retain information and rewrite information even when no power is supplied. The non-volatile memory 110 stores various information required for the operation of the circuit device 20. The non-volatile memory 110 can be implemented using an EEPROM (Electrically Erasable Programmable Read-Only Memory) implemented using a FAMOS (Floating Gate Avalanche Injection MOS) memory or a MONOS (Metal-Oxide-Nitride-Oxide-Silicon) memory. Furthermore, the non-volatile memory 110 stores correction data such as primary correction data and higher-order correction data used for temperature compensation in the temperature compensation circuit 40.

[0055] The output circuit 80 outputs a clock signal CK based on the oscillation signal from the oscillation circuit 30. For example, the output circuit 80 buffers the oscillation signal, which is the oscillation clock signal from the oscillation circuit 30, and outputs it as the clock signal CK to the pad PCK. Furthermore, this clock signal CK is output externally via the clock output terminal TCK of the oscillator 4. For example, the output circuit 80 outputs the clock signal CK in the form of a single-ended CMOS signal. Alternatively, the output circuit 80 may output the clock signal CK in a signal form other than CMOS. Alternatively, a clock signal generation circuit, such as a PLL circuit, may be provided after the oscillation circuit 30. This clock signal generation circuit generates a clock signal CK with a frequency obtained by multiplying the frequency of the oscillation signal, and the output circuit 80 buffers the clock signal CK generated by this clock signal generation circuit before outputting it.

[0056] Furthermore, in Figure 2In the circuit, the higher-order correction circuit 44 includes a first compensation circuit 47 and a second compensation circuit 48. Additionally, the tail current control circuit 70 includes a first tail current control circuit 71 and a second tail current control circuit 72. The first compensation circuit 47 performs temperature compensation on the low-temperature side, and the second compensation circuit 48 performs temperature compensation on the high-temperature side. The low-temperature side is, for example, a first temperature range, and the high-temperature side is, for example, a second temperature range. Specifically, the first compensation circuit 47 has a differential pair circuit DPL for the low-temperature side as a differential pair circuit DP, and generates a current for temperature compensation on the low-temperature side (first temperature range) through the differential pair circuit DPL. The second compensation circuit 48 has a differential pair circuit DPH for the high-temperature side as a differential pair circuit DP, and generates a current for temperature compensation on the high-temperature side (second temperature range) through the differential pair circuit DPH. The differential pair circuit DPL is the first differential pair circuit, and the differential pair circuit DPH is the second differential pair circuit. Furthermore, the first compensation circuit 47 can include multiple differential pair circuits DPL, and the second compensation circuit 48 can include multiple differential pair circuits DPH.

[0057] The first tail current control circuit 71 outputs a bias voltage VBL, used to control the tail current of the differential pair circuit DPL on the low-temperature side, to the differential pair circuit DPL. The second tail current control circuit 72 outputs a bias voltage VBH, used to control the tail current of the differential pair circuit DPH on the high-temperature side, to the differential pair circuit DPH. The differential pair circuit DPL is input with a temperature detection voltage VTS from the temperature detection circuit 50 and a reference voltage from the reference voltage generation circuit 60. The tail current is controlled by the bias voltage VBL to generate the high-order compensation current on the low-temperature side. The differential pair circuit DPH is input with a temperature detection voltage VTS from the temperature detection circuit 50 and a reference voltage from the reference voltage generation circuit 60. The tail current is controlled by the bias voltage VBH to generate the high-order compensation current on the high-temperature side. The polarities of the temperature characteristics of the temperature detection voltage VTS input to the differential pair circuit DPL and the temperature detection voltage VTS input to the differential pair circuit DPH can be different.

[0058] Specifically, the first tail current control circuit 71 on the low-temperature side controls the first tail current, which is the tail current of the differential pair circuit DPL, in a manner that makes the current value minimum at the inflection point temperature of the temperature compensation voltage VCP and increases as the temperature decreases from the inflection point temperature. For example, the first tail current is controlled in a manner that makes the current value monotonically increase as the temperature decreases from the inflection point temperature. In this case, the first tail current control circuit 71 controls the first tail current in a manner that makes the current value minimum when the temperature is higher than the inflection point temperature. That is, the first tail current is controlled in a manner that makes the current value increase when the temperature is lower than the inflection point temperature and minimum when the temperature is higher than the inflection point temperature.

[0059] Furthermore, the second tail current control circuit 72 on the high-temperature side controls the second tail current, which is the tail current of the differential pair circuit DPH, in a manner that makes the current value minimum at the inflection point temperature of the temperature compensation voltage VCP and increases as the temperature increases from the inflection point temperature. For example, the second tail current is controlled in a manner that makes the current value monotonically increase as the temperature rises from the inflection point temperature. In this case, the second tail current control circuit 72 controls the second tail current in a manner that makes the current value minimum when the temperature is lower than the inflection point temperature. That is, the second tail current is controlled in a manner that makes the current value increase when the temperature is higher than the inflection point temperature and minimum when the temperature is lower than the inflection point temperature.

[0060] In this case, the current value of the first tail current of the differential pair circuit DPL, controlled by the first tail current control circuit 71, increases with a linear characteristic as the temperature decreases from the inflection point temperature. That is, the current value of the first tail current monotonically increases with a linear characteristic from the inflection point temperature on the low-temperature side. Furthermore, the current value of the second tail current of the differential pair circuit DPH, controlled by the second tail current control circuit 72, increases with a linear characteristic as the temperature increases from the inflection point temperature. That is, the current value of the second tail current monotonically increases with a linear characteristic from the inflection point temperature on the high-temperature side.

[0061] Figure 3 An example of the structure of the temperature compensation circuit 40 is shown. However, the temperature compensation circuit 40 is not limited to... Figure 3 The structure can be transformed in various ways, such as omitting some of its constituent elements, adding other constituent elements, or replacing some of its constituent elements with other constituent elements.

[0062] The temperature compensation circuit 40 is a circuit that outputs a temperature compensation voltage VCP by using a polynomial approximation with temperature as the variable. This temperature compensation circuit 40 includes a current generation circuit 42 and a current-to-voltage conversion circuit 46. The current generation circuit 42 generates a temperature compensation current ICP based on the temperature detection result from the temperature detection circuit 50. For example, the current generation circuit 42 generates a temperature compensation current ICP for temperature compensation of the frequency-temperature characteristics of the oscillator 10 based on the temperature detection voltage VTS, which is the temperature detection result. The temperature compensation current ICP is also referred to as a function current. Furthermore, the current-to-voltage conversion circuit 46 converts the temperature compensation current ICP from the current generation circuit 42 into a voltage and outputs the temperature compensation voltage VCP. Specifically, the current-to-voltage conversion circuit 46 outputs the temperature compensation voltage VCP through the operational amplifier OPD1.

[0063] The current generation circuit 42 includes a primary correction circuit 43 and a higher-order correction circuit 44. The primary correction circuit 43 and the higher-order correction circuit 44 are also referred to as primary compensation circuit and higher-order compensation circuit, respectively. The primary correction circuit 43 outputs a primary compensation current, which is an approximate first-order function, based on the temperature detection voltage VTS. For example, the primary correction circuit 43 outputs a primary compensation current based on the first-order correction data corresponding to the first-order coefficients of the polynomial in the polynomial approximation. The higher-order correction circuit 44 outputs a higher-order compensation current ICU, which is an approximate higher-order function, to the current-to-voltage conversion circuit 46 based on the temperature detection voltage VTS. For example, the higher-order correction circuit 44 outputs a higher-order compensation current ICU based on the higher-order correction data corresponding to the higher-order coefficients of the polynomial in the polynomial approximation. The current obtained by adding the higher-order compensation current ICU to the primary compensation current of the primary correction circuit 43 is used as the temperature compensation current ICP and input to the current-to-voltage conversion circuit 46.

[0064] like Figure 3 As shown, the primary calibration circuit 43 includes operational amplifier OPD2 and resistors RD1 and RD2. Additionally, the primary calibration circuit 43 may include a resistor RD3 with a variable resistance value. The reference voltage VRC is input to the non-inverting input terminal of operational amplifier OPD2. Resistor RD1 is positioned between node ND1 of the input temperature sensing voltage VTS and node ND2 of the inverting input terminal of operational amplifier OPD2. Resistor RD2 is positioned between node ND2 and node ND3 of the output terminal of operational amplifier OPD2. Resistor RD3 is positioned between node ND3 and node ND4 of the output terminal of current generation circuit 42.

[0065] The current-to-voltage conversion circuit 46 outputs a temperature-compensated voltage VCP by performing current-to-voltage conversion on the temperature-compensated current ICP, which is the sum of the primary compensation current and the higher-order compensation current ICU. This generates a temperature-compensated voltage VCP that approximates a polynomial function. Specifically, the current-to-voltage conversion circuit 46 includes an operational amplifier OPD1 and a feedback resistor RD. The reference voltage VRC is input to the non-inverting input terminal of the operational amplifier OPD1, and the output node ND4 of the current generation circuit 42 is connected to the inverting input terminal of the operational amplifier OPD1. The resistor RD is positioned between the output terminal and the inverting input terminal of the operational amplifier OPD1. Furthermore, in Figure 3 In this configuration, the phase compensation capacitor CD is placed between the output terminal and the inverting input terminal of the operational amplifier OPD1, but it can also be configured without the capacitor CD.

[0066] so, Figure 3The temperature compensation circuit 40 includes a primary correction circuit 43 and a higher-order correction circuit 44 that receive an input temperature detection voltage VTS. It also includes a current generation circuit 42 that generates a temperature compensation current ICP via the primary correction circuit 43 and the higher-order correction circuit 44, and a current-to-voltage conversion circuit 46 that converts the temperature compensation current ICP into a voltage and outputs a temperature compensation voltage VCP. According to this configuration, the temperature compensation current ICP, generated by the current generation circuit 42 based on the temperature detection voltage VTS, can be converted into a voltage via the current-to-voltage conversion circuit 46 and output as the temperature compensation voltage VCP.

[0067] Figure 4 This is an explanatory diagram regarding temperature compensation. The 0th, 1st, 2nd, 3rd, 4th, and 5th order components represent the characteristics of these components as 0th, 1st, 2nd, 3rd, 4th, and 5th order functions relative to temperature, respectively. Then, through... Figure 3 The primary correction circuit 43 performs temperature compensation for the first-order component, and the higher-order correction circuit 44 performs temperature compensation for the second-order, third-order, fourth-order, and fifth-order components. Alternatively, the corrections for the second-order and fourth-order components can be omitted. Based on... Figure 4 The temperature compensation voltage VCP generated by such temperature compensation causes a change in the capacitance of the variable capacitor circuit 32, thereby eliminating temperature-based variations in the oscillation frequency of the oscillator 10 and making the oscillation frequency constant relative to temperature changes. In this case, the temperature characteristics of the oscillation frequency of the oscillator 10 result in process deviations. Therefore, during product manufacturing, the clock frequency of the oscillator 4 is monitored, and appropriate correction data based on the monitoring results is written into the non-volatile memory 110 of the circuit device 20 for temperature compensation based on this correction data.

[0068] Figure 5 This is an example of the structure of the first compensation circuit 47 and the second compensation circuit 48 disposed in the high-order correction circuit 44. The first compensation circuit 47 performs temperature compensation within a first temperature range, which is the temperature range on the low-temperature side, and the second compensation circuit 48 performs temperature compensation within a second temperature range, which is the temperature range on the high-temperature side. The first compensation circuit 47 includes multiple differential pair circuits DPL1 and DPL2 on the low-temperature side. The second compensation circuit 48 includes multiple differential pair circuits DPH1 and DPH2 on the high-temperature side.

[0069] Furthermore, the first tail current control circuit 71 of the tail current control circuit 70 outputs a bias voltage VBL to the differential pair circuits DPL1 and DPL2 on the low-temperature side, thereby causing the tail current IBL to flow to the differential pair circuits DPL1 and DPL2. Additionally, the second tail current control circuit 72 of the tail current control circuit 70 outputs a bias voltage VBH to the differential pair circuits DPH1 and DPH2 on the high-temperature side, thereby causing the tail current IBH to flow to the differential pair circuits DPH1 and DPH2.

[0070] Furthermore, each differential pair circuit of DPL1, DPL2, DPH1, and DPH2 includes a first bipolar transistor and a second bipolar transistor forming a differential pair. A temperature detection voltage VTS is input to the base of the first bipolar transistor, and any one of VL1, VL2, VH1, and VH2, serving as a reference voltage, is input to the base of the second bipolar transistor. These reference voltages are determined by… Figure 2 The reference voltage generation circuit 60 generates the voltage. In addition, each differential pair circuit includes a third bipolar transistor that serves as a current source, and the base of the third bipolar transistor is supplied with a bias voltage VBL from the first tail current control circuit 71 or a bias voltage VBH from the second tail current control circuit 72.

[0071] Furthermore, the first compensation circuit 47 generates a temperature compensation current IL = IL1 + IL2 within the low-temperature side temperature range. Additionally, the second compensation circuit 48 generates a temperature compensation current IH = IH1 + IH2 within the high-temperature side temperature range. Moreover, tail currents IBL = IL1 + IE1 and IBL = IL2 + IE2 flow in the differential pair circuits DPL1 and DPL2 of the first compensation circuit 47. Furthermore, tail currents IBH = IH1 + IE3 and IBH = IH2 + IE4 flow in the differential pair circuits DPH1 and DPH2 of the second compensation circuit 48.

[0072] Furthermore, within the low-temperature range, the current IL = IL1 + IL2 increases, while the current IH = IH1 + IH2 decreases, for example, becoming 0. Conversely, within the high-temperature range, the current IH = IH1 + IH2 increases, while the current IL = IL1 + IL2 decreases, for example, becoming 0. By using the high-order correction circuit 44 constructed in this way, such as... Figure 6 As shown, it can generate high-order compensation currents such as 2nd, 3rd, 4th, and 5th orders. For example, the current IL flowing to the first compensation circuit 47 within the temperature range of the low-temperature side is set to... Figure 6 The characteristic shown in K1 is used to set the current IH flowing to the second compensation circuit 48 within the high-temperature side to the characteristic shown in K2. This allows the generation of a secondary, higher-order compensation current as shown in K3. Furthermore, the current IL flowing to the first compensation circuit 47 within the low-temperature side is set to... Figure 6 The characteristic shown in K4 sets the current IH flowing to the second compensation circuit 48 within the temperature range of the high-temperature side to the characteristic shown in K5. Thus, a third-order compensation current as shown in K6 can be generated. Fourth-order and fifth-order compensation currents can also be generated using the same method.

[0073] In addition, Figure 5 The diagram shows a case where each compensation circuit in the first compensation circuit 47 and the second compensation circuit 48 includes two differential pair circuits, but the number of differential pair circuits included in each compensation circuit is not limited to this; the number of differential pair circuits can also be three or more. Furthermore, in Figure 5 In the case of the structure, the polarity of the temperature characteristic of the temperature detection voltage VTS used in the first compensation circuit 47 on the low-temperature side is different from the polarity of the temperature characteristic of the temperature detection voltage VTS used in the second compensation circuit 48 on the high-temperature side. For example, when a temperature detection voltage VTS with a negative temperature characteristic is used in the first compensation circuit 47 on the low-temperature side, a temperature detection voltage VTS with a positive temperature characteristic can be used in the second compensation circuit 48 on the high-temperature side.

[0074] Figure 7 An example of the structure of a temperature detection circuit 50 is shown. The temperature detection circuit 50 includes a temperature sensor 52 and an output circuit 54. The temperature sensor 52 includes a constant current source IS1, a bipolar transistor BPE1, and a resistor RE1. The constant current source IS1, resistor RE1, and bipolar transistor BPE1 are connected in series between the power supply node on the high-potential side and the power supply node on the low-potential side. Specifically, the connection node between the constant current source IS1 and one end of the resistor RE1 is connected to the base of the bipolar transistor BPE1, and the other end of the resistor RE1 is connected to the collector of the bipolar transistor BPE1. Furthermore, the emitter of the bipolar transistor BPE1 is connected to the power supply node on the low-potential side. The output circuit 54 outputs a temperature detection voltage VTS based on the sensor voltage VSE from the temperature sensor 52.

[0075] exist Figure 7 In this diagram, the current flowing from the constant current source IS1 is denoted as IE, the resistance value of resistor RE1 is represented by the same sign RE1, and the base-emitter voltage of bipolar transistor BPE1 is denoted as VBE1. Thus, the sensor voltage is expressed as VSE = VBE1 - IE × RE1. The base-emitter voltage VBE1 of bipolar transistor BPE1 has a negative temperature characteristic; therefore, the temperature detection voltage VTS generated based on the sensor voltage VSE also has a negative temperature characteristic.

[0076] Figure 8 Other structural examples of the temperature detection circuit 50 are shown. Figure 8The temperature sensor 52 in the temperature detection circuit 50 includes constant current sources IS1 and IS2, bipolar transistors BPE1 and BPE2, and resistors RE1 and RE3. The connection structure of the constant current source IS1, bipolar transistor BPE1, and resistor RE1 is similar to... Figure 7 The structure is the same as the example. Furthermore, the constant current source IS2, resistor RE3, and bipolar transistor BPE2 are connected in series between the power supply node on the high-potential side and the collector node of bipolar transistor BPE1. Specifically, the connection node between the constant current source IS2 and one end of resistor RE3 is connected to the base of bipolar transistor BPE2, and the other end of resistor RE3 is connected to the collector of bipolar transistor BPE2. Additionally, the emitter of bipolar transistor BPE2 is connected to the collector of bipolar transistor BPE1.

[0077] exist Figure 8 In this design, the collector voltages of bipolar transistors BPE1 and BPE2 are set as VGA and VSE, respectively; the current flowing through constant current sources IS1 and IS2 is set as IE; and the resistance values ​​of resistors RE1 and RE3 are represented by the same designation RE1 and RE2. Furthermore, the base-emitter voltages of bipolar transistors BPE1 and BPE2 are set as VBE1 and VBE2, respectively. Thus, the sensor voltage is expressed as VSE = VBE2 - IE × RE3 + VGA = VBE1 + VBE2 - IE × (RE1 + RE3). Since the base-emitter voltages VBE1 and VBE2 of bipolar transistors BPE1 and BPE2 have negative temperature characteristics, the temperature detection voltage VTS generated based on the sensor voltage VSE also has negative temperature characteristics.

[0078] exist Figure 8 In the structural example, two bipolar transistors BPE1 and BPE2 are provided. Therefore, the two base-emitter voltages VBE1 and VBE2 are added together. Thus, with... Figure 7 Compared to the previous structure, this structure can increase the slope of the temperature detection voltage VTS relative to the temperature, and can generate a temperature detection voltage VTS with high temperature sensitivity.

[0079] Figure 9 This shows a specific structural example of the temperature detection circuit 50 and the temperature compensation circuit 40. The structure of the temperature compensation circuit 40 is similar to... Figure 3 The same applies, therefore detailed explanations are omitted. Furthermore, in Figure 9 The diagram shows an example of the structure of the output circuit 54 disposed in the temperature detection circuit 50. The output circuit 54 includes an operational amplifier OPD3 and resistors RD4 and RD5.

[0080] The non-inverting input terminal of operational amplifier OPD3 receives the sensor voltage VSE from temperature sensor 52. Resistor RD4 is positioned between the input node of the reference voltage VR0 used for bias adjustment (0th correction) and node ND0 of the inverting input terminal of operational amplifier OPD3. Resistor RD5 is positioned between node ND0 and node ND1 of the output terminal of operational amplifier OPD3. Furthermore, in this embodiment, the same symbols are used to represent the resistors and their resistance values. For example, the resistance values ​​of resistors RD, RD1, RD2, RD3, RD4, and RD5 are also represented as RD, RD1, RD2, RD3, RD4, and RD5. Thus, the temperature detection voltage VTS is as shown in equation (1).

[0081] [Mathematical Expression 1]

[0082] Furthermore, the voltage VTS2 output by the operational amplifier OPD2 of the primary correction circuit 43 is shown in equation (2) below. This voltage VTS2 has, for example, a positive temperature characteristic, and therefore can be called the temperature detection voltage.

[0083] [Mathematical Expression 2]

[0084] Furthermore, when the high-order compensation current from the high-order correction circuit 44 is set to ICU, the temperature compensation voltage VCP is expressed as shown in equation (3).

[0085] [Mathematical Expression 3]

[0086] Figure 10 The temperature characteristics of the sensor voltage VSE, temperature detection voltage VTS, voltage VTS2, and reference voltage VRC are shown. Figure 10 As shown, the temperature detection voltage VTS and the sensor voltage VSE have negative temperature characteristics, while voltage VTS2 has a positive temperature characteristic. Furthermore, the temperature detection voltage VTS, voltage VTS2, and reference voltage VRC intersect at the inflection point T0.

[0087] 2. Differential control of the tail current of the circuit

[0088] Figure 11 This illustrates a structural example of a differential pair circuit DP. This differential pair circuit DP corresponds to... Figure 2 , Figure 5The differential pair circuits are DPL, DPH, DPL1, DPL2, DPH1, and DPH2. Furthermore, in this embodiment, for the sake of simplicity, the differential pair circuits DPL, DPL1, and DPL2 on the low-temperature side and DPH, DPH1, and DPH2 on the high-temperature side are appropriately referred to as differential pair circuit DP.

[0089] like Figure 11 As shown, the differential pair circuit DP includes a bipolar transistor TR1 and a resistor R1 connected in series between nodes N1 and VDL. Furthermore, the differential pair circuit DP includes a bipolar transistor TR2 and a resistor R2 connected in parallel with these TR1 and R1, connected in series between nodes N1 and VDL. These npn bipolar transistors TR1 and TR2 are the transistors constituting the differential pair. Additionally, the differential pair circuit DP includes a bipolar transistor TR3 and a resistor R3 connected in series between nodes N1 and VSS.

[0090] A voltage VT1 is input to the base of bipolar transistor TR1 in the differential pair, and a voltage VT2 is input to the base of bipolar transistor TR2 in the differential pair. As a result, current IER flows to bipolar transistor TR1, and current ITH flows to bipolar transistor TR2. In this case, in the differential pair circuit DP (DPL, DPL1, DPL2) on the low-temperature side, a reference voltage VR is input to the base of bipolar transistor TR1, and a temperature detection voltage VTS is input to the base of bipolar transistor TR2. On the other hand, in the differential pair circuit DP (DPH, DPH1, DPH2) on the high-temperature side, a temperature detection voltage VTS is input to the base of bipolar transistor TR1, and a reference voltage VR is input to the base of bipolar transistor TR2. In this case, for example, the polarity of the temperature characteristic of the temperature detection voltage VTS used in the differential pair circuit DP on the low-temperature side is made different from the polarity of the temperature detection voltage VTS used in the differential pair circuit DP on the high-temperature side.

[0091] Additionally, a bias voltage VB is input to the base of the bipolar transistor TR3, which acts as a current source, thereby causing the tail current IB to flow into the bipolar transistor TR3. For example, as Figure 5 As shown, the bipolar transistor TR3 of the differential pair circuits DPL1 and DPL2, which is biased by the bias voltage VBL from the first tail current control circuit 71, directs the tail current IBL to the low-temperature side. Additionally, the bipolar transistor TR3 of the differential pair circuits DPH1 and DPH2, which is biased by the bias voltage VBH from the second tail current control circuit 72, directs the tail current IBH to the high-temperature side.

[0092] exist Figure 11 In the bipolar transistor TR3, the tail current IB flowing to the bipolar transistor TR1 and TR2 and the currents IER and ITH flowing to the bipolar transistors TR1 and TR2 satisfy the following relationship (4).

[0093] [Mathematical Expression 4]

[0094] Furthermore, when the base-emitter voltage of the bipolar transistor is set to VBE and the saturation current is set to IS, the collector current IC of the bipolar transistor is expressed as shown in equation (5).

[0095] [Mathematical Expression 5]

[0096] In equation (5) above, VT = kT / q, where k is the Boltzmann constant, T is the temperature, and q is the charge of the electron. Furthermore, when the voltage at node N1 is set to VX, the base-emitter voltage of bipolar transistor TR1 becomes VBE = VT1 - VX, and the base-emitter voltage of bipolar transistor TR2 becomes VBE = VT2 - VX. Therefore, the currents ITH and IER flowing to bipolar transistors TR2 and TR1 are shown in equations (6) and (7) below.

[0097] [Mathematical Expression 6]

[0098] According to equations (6) and (7) above, IER / ITH is shown in equation (8) below.

[0099] [Mathematical Expression 7]

[0100] Therefore, according to equations (4) and (8) above, the current ITH flowing to the bipolar transistor TR2 for temperature compensation is expressed as shown in equation (9).

[0101] [Mathematical Expression 8]

[0102] Figure 12 This is an example of the temperature characteristic of the current ITH used for temperature compensation in the differential pair circuit DP on the low-temperature side. In the differential pair circuit DP on the low-temperature side, VT1=VR and VT2=VTS are input to the bases of bipolar transistors TR1 and TR2, respectively. The current ITH corresponds to... Figure 5 The current IL, and the reference voltage VR correspond to voltages VL1 and VL2. The voltage VT1 = VR is set to... Figure 12The temperature characteristics are shown in A1, A2, A3, A4, A5, and A6. For example, A1, A2, A3, A4, A5, and A6 represent the temperature characteristics when VT1=VR=0.95V, 0.90V, 0.85V, 0.80V, 0.75V, and 0.70V, respectively. For instance, as VT1=VR decreases, the temperature characteristics change as shown in A1, A2, A3, A4, A5, and A6. Thus, by setting the reference voltage VR, various temperature characteristics can be achieved, and by combining these temperature characteristics, the desired temperature characteristics can be achieved.

[0103] Figure 13 This is an example of the temperature characteristic of the current ITH used for temperature compensation in the differential pair circuit DP flowing to the high-temperature side. In the differential pair circuit DP on the high-temperature side, VT1=VTS and VT2=VR are input to the bases of bipolar transistors TR1 and TR2, respectively. That is, they become voltage inputs opposite to those on the low-temperature side. The current ITH corresponds to... Figure 5 The current IH is given, and the reference voltage VR corresponds to voltages VH1 and VH2. The voltage VT2 = VR is set to... Figure 13 The temperature characteristics are as shown in A11, A12, A13, A14, A15, and A16. For example, as VT2=VR increases, the temperature characteristics change as shown in A11, A12, A13, A14, A15, and A16. Thus, various temperature characteristics can be achieved on the high-temperature side by setting the reference voltage VR, and the desired temperature characteristics can be achieved by combining these temperature characteristics. Therefore, by using the temperature compensation current ITH=IH on the low-temperature side and the temperature compensation current ITH=IL on the high-temperature side, a higher-order compensation current with the desired temperature characteristics can be generated.

[0104] In recent years, there has been a demand for lower power supply voltage VDD. By lowering the power supply voltage VDD, it is possible to achieve lower power consumption in circuit device 20, oscillator 4, and other components.

[0105] However, as the power supply voltage VDD decreases, the gain of the temperature characteristic of the temperature sensing voltage VTS input to the differential pair circuit DP decreases, resulting in the problem that the transistors of the differential pair through the differential pair circuit DP alone cannot generate appropriate high-order compensation current.

[0106] For example, Figure 14 B1 is Figure 8 The temperature detection voltage VTS of the temperature detection circuit 50 has a temperature characteristic, and B2 is... Figure 7 The temperature sensing circuit 50 shows the temperature sensing voltage VTS's temperature characteristics. Additionally, B3 indicates the lower limit of the power supply voltage that is being lowered. According to... Figure 8 Such a structure with two bipolar transistors, such as Figure 14As shown in B1, the gain of the temperature characteristic can be increased. Here, the gain of the temperature characteristic corresponds to the slope of the first-order temperature characteristic. However, it is difficult to use when the power supply voltage is lowered as shown in B3. Figure 8 A temperature sensing circuit 50 with such a two-stage bipolar transistor structure. Furthermore, when dealing with low power supply voltages... Figure 7 When the temperature detection circuit 50 uses a single-stage bipolar transistor structure, as shown in B2, the slope of the primary characteristic of the gain of the temperature characteristic of the temperature detection voltage VTS becomes smaller.

[0107] Furthermore, conventionally, a constant tail current IB flows through the differential pair circuit DP. However, when the gain of the temperature characteristic of the temperature detection voltage VTS decreases as described above, there is a problem that it is difficult to generate an appropriate high-order compensation current in the constant tail current IB.

[0108] Furthermore, the temperature compensation current ITH generated by the differential pair circuit DP is expressed as in equation (9) above. Moreover, when ΔVT=VT1-VT2 in equation (9) becomes smaller due to factors such as the reduction of the power supply voltage, it is difficult to reduce the temperature compensation current ITH near the inflection point temperature (e.g., 25°C to 35°C).

[0109] For example, Figure 15 C1, C2, C3, and C4 are examples of the temperature characteristics of the ITH current used for temperature compensation. Figure 16 It is Figure 15 The temperature characteristics are magnified along the longitudinal axis, which represents the current axis. C1, C2, C3, and C4 represent the temperature characteristics when ΔVT = VT1 - VT2 is 0.25V, 0.2V, 0.15V, and 0.1V, respectively. Figure 16 As shown in C2, C3, and C4, when ΔVT = VT1 - VT2 is as small as 0.2V, 0.15V, and 0.1V, it is difficult to make the current ITH zero near the inflection point temperature.

[0110] For example, suppose to Figure 3 The reference voltage VRC input to the non-inverting input terminals of the operational amplifiers OPD1 and OPD2 in the temperature compensation circuit 40 is 0.7V at the inflection point temperature. Therefore, as... Figure 10 As shown, at the inflection point temperature T0, the temperature sensing voltage VTS is equal to the reference voltage VRC. Figure 11 VT2 = VTS becomes 0.7V. Furthermore, based on a power supply voltage with a lower limit of, for example, 1.0V to 1.1V, Figure 2 The reference voltage generation circuit 60 generates a reference voltage VR, for example, through a bandgap reference circuit. Therefore, Figure 11VT1 = VR has a maximum value of approximately 0.9V. Therefore, ΔVT = VT1 - VT2 has a maximum value of approximately 0.2V, and the temperature characteristic of the current ITH becomes... Figure 16 The temperature characteristics shown by C2, C3, and C4. Therefore, a problem arises where the current ITH cannot be zero at the inflection point temperature. For example, at ΔVT = 0.2V... Figure 16 In the case of C2, the temperature is 30℃ and a current of about 5nA flows.

[0111] For example, if ΔVT = VT1 - VT2 is large enough, then the temperature characteristic of the current ITH becomes Figure 15 , Figure 16 The temperature characteristics shown in C1 allow for the setting of the current ITH to be close to zero even in structures using a constant tail current IB as in the past. However, when ΔVT = VT1 - VT2 is small, the current ITH cannot be zero near the inflection point temperature. Furthermore, the higher-order compensation current becomes the sum of the currents ITH of multiple differential pair circuits DP, thus increasing the value of the higher-order compensation current at the inflection point temperature and hindering low power consumption.

[0112] Furthermore, when the ITH current cannot be reduced at the inflection point temperature, matching the characteristics of the higher-order compensation current and adjusting the inflection point become difficult. For example, the higher-order compensation current at low temperatures is achieved by... Figure 12 It is generated by adding the currents ITH with various temperature characteristics shown in A1~A6, and on the high-temperature side it is generated by... Figure 13 The current ITH with various temperature characteristics shown in A11~A16 is added together to generate it. However, in cases such as Figure 15 The current ITH with a relatively small temperature characteristic (ΔVT=VT1-VT2) shown in C2~C4 generates problems such as increased current consumption. Therefore, only current ITH with a larger temperature characteristic (ΔVT=VT1-VT2) can be used, making it difficult to match the characteristics of higher-order compensation currents, and also making it difficult to adjust the inflection point.

[0113] In addition, when in Figure 5 When the current IL of the first compensation circuit 47 flows through the current IH of the second compensation circuit 48 within the temperature range of the low-temperature side, or when the current IH of the second compensation circuit 48 flows through the current IL of the first compensation circuit 47, it becomes useless power consumption. Furthermore, when the current ITH cannot be zero at the inflection point temperature, and a non-zero current ITH flows in the differential pair circuit DP on the high-temperature side within the temperature range of the low-temperature side, or when a non-zero current ITH flows in the differential pair circuit DP on the low-temperature side within the temperature range of the high-temperature side, such useless power consumption occurs.

[0114] Therefore, in this embodiment, the following method is adopted: the tail current of the differential pair circuit DP of the higher-order correction circuit 44 is made to have temperature characteristics, and a higher-order compensation current is generated by such a differential pair circuit DP. That is, previously the tail current of the differential pair circuit DP was a constant current and did not have temperature characteristics, but this disclosure makes the tail current have strong temperature characteristics by making the current value change according to temperature changes. That is, the tail current control circuit 70 controls the tail current of the differential pair circuit DP in a way that the current value is the minimum current value at the inflection point temperature of the temperature compensation voltage VCP and increases according to the temperature change from the inflection point temperature.

[0115] Figure 17 This illustrates a structural example of a tail current control circuit 70 that performs such tail current control. Furthermore, Figure 17 In reality, the structures of the first tail current control circuit 71 and the second tail current control circuit 72 are examples, but for the sake of simplicity, the structure of the tail current control circuit 70 will be described using them as representatives. Furthermore, the tail current control circuit 70 is not limited to... Figure 17 The structure can be modified in various ways, such as omitting some of its constituent elements, adding other constituent elements, or replacing some of its constituent elements with other constituent elements.

[0116] Figure 17 The tail current control circuit 70 is a transconductance amplifier that converts voltage difference into current. Specifically, the tail current control circuit 70 converts the voltage difference (VA1-VA2) between voltage VA1 and voltage VA2 (which has different temperature characteristics) into current, generating a current IQ to control the tail current of the differential pair circuit DP. Voltage VA1 is the first voltage, and voltage VA2 is the second voltage. Based on the current IQ generated by the tail current control circuit 70, a bias voltage VB (VBL, VBH) is generated, and the tail current of the differential pair circuit DP is controlled based on this bias voltage VB.

[0117] Specifically, the tail current control circuit 70 includes a differential section 74 and an output section 75. The differential section 74 of the tail current control circuit 70 includes transistors TA1, TA2 that form a current mirror circuit, bipolar transistors TA3, TA4 that are transistors of a differential pair, and a transistor TA5 that is a current source. The P-type transistors TA1, TA2 are provided between the node of VDL and nodes NA1, NA2, and their gates are connected to node NA1. The npn bipolar transistor TA3 is provided between node NA1 and node NA3, and its base is connected to node NA4 of the output section 75. The npn bipolar transistor TA4 is provided between node NA2 and node NA3, and a voltage VA1 is input to its base. Additionally, a modification can be implemented by using N-type transistors of MOS instead of the npn bipolar transistors TA3, TA4. The N-type transistor TA5 is provided between node NA3 and the node of VSS, and a bias voltage VBN is input to its gate.

[0118] The output section 75 of the tail current control circuit 70 includes a transistor TA6 and a resistor RA that are serially provided between the node of VDL and the node of VSS. In addition, the output section 75 includes a transistor TA7 and a bipolar transistor TA8 that are serially provided between the node of VDL and the node of VSS. The P-type transistor TA6 is provided between the node of VDL and node NA-4, and the output voltage VAQ of the output section 75 is input to its gate. The resistor RA is provided between node NA4 and the input node of voltage VA2. The P-type transistor TA7 is provided between the node of VDL and node NA5. The bipolar transistor TA8 is provided between node NA5 and the node of VSS, and its base and collector are connected to node NA5 of the bias voltage VB.

[0119] In Figure 17 the tail current control circuit 70, through the virtual ground of the differential section 74, the voltage of node NA4 to which the base of the bipolar transistor TA3 that forms a differential pair is connected is equal to the voltage VA1 input to the base of the bipolar transistor TA4 that forms a differential pair. That is, the voltage of node NA4 becomes VA1. Moreover, since the output voltage VAQ of the differential section 74 is commonly input to the gates of the transistors TA6, TA7 of the output section 75, a current IQ having the same current value as the current flowing through the transistor TA6 flows through the transistor TA7. Therefore, when the resistance value of the resistor RA is set to RA with the same sign, when VA1 > VA2, a current IQ as shown in the following equation (ten) is generated. On the other hand, when VA1 < VA2, the voltage of node NA2 of the differential section 74 rises, and the transistors TA6, TA7 are cut off. Therefore, the current value of the current IQ becomes zero as shown in the following equation (eleven).

[0120] [Mathematical formula 9]

[0121] Thus, when VA1 > VA2, Figure 17 the tail current control circuit 70 of Figure 17 operates as a transconductance amplifier that converts the voltage difference between voltage VA1 and voltage VA2, i.e., (VA1 - VA2), into a current IQ = (VA1 - VA2) / RA, and the tail current corresponding to the current IQ flows to the differential pair circuit DP.

[0122] Moreover, in the present embodiment, voltages VA1 and VA2 such as VA1 = VTS and VA2 = VTS2 are input to the tail current control circuit 70 (the first tail current control circuit 71) on the low temperature side. Therefore, when VA1 > VA2, a current IQ as shown in the following equation (12) is generated in the tail current control circuit 70 on the low temperature side. On the other hand, when VA1 < VA2, the current value of the current IQ becomes zero as shown in the following equation (13).

[0123] [Mathematical formula 10]

[0124] Thereby, a tail current corresponding to the current IQ in the above equations (12) and (13) flows through the differential pair circuit DP on the low temperature side.

[0125] On the other hand, voltages VA1 and VA2 such as VA1 = VTS2 and VA2 = VTS are input to the tail current control circuit 70 (the second tail current control circuit 72) on the high temperature side. Therefore, when VA1 > VA2, a current IQ as shown in the following equation (14) is generated in the tail current control circuit 70 on the high temperature side. On the other hand, when VA1 < VA2, the current value of the current IQ becomes zero as shown in the following equation (15).

[0126] [Mathematical formula 11][[ID=二十一]] [[ID=二十二]] [[ID=二十三]]<者 [[ID=二十四]]

[0127] [[ID=二十五]] [[ID=二十六]]

[0128] [[ID=二十七]] Figure 18 [[ID=二十八]] Figure 18 [[ID=二十九]] Figure 9 [[ID=三十]] Figure 1 [[ID=三十一]] Figure 2 [[ID=三十二]] [[ID=三十三]]

[0129] [[ID=三十四]] Figure 18 [[ID=三十五]] Figure 18 [[ID=三十六]] [[ID=三十七]]

[0130] [[ID=三十八]] Figure 18 [[ID=三十九]] [[ID=四十]]

[0131] [[ID=四十一]] Figure 5 [[ID=四十二]] Figure 18 [[ID=四十三]] Figure 18 [[ID=四十四]] [[ID=四十五]]

[0132] [[ID=四十六]] Figure 18 [[ID=四十七]] [[ID=四十八]]

[0133] [[ID=四十九]] Figure 18 [[ID=五十]] [[ID=五十一]]

[0134] [[ID=五十二]] Figure 5 [[ID=五十三]] Figure 18 [[ID=五十四]] Figure 18 [[ID=五十五]] [[ID=五十六]]<0000照409> [[ID=五十七]] Figure 18 [[ID=五十八]] Figure 18 [[ID=五十九]] [[ID=六十]]

[0136] [[ID=六十一]] Figure 19 [[ID=六十二]] Figure 20 [[ID=六十三]]<000041出6> [[ID=六十四]] Figure 19 [[ID=六十五]]] Figure 19 [[ID=六十六]] Figure 19 [[ID=六十七]] [[ID=六十八]]

[0137] [[ID=六十九]] Figure 19 [[ID=七十]]<0照000423> [[ID=七十一]] [[ID=七十二]]

[0138] [[ID=七十三]] Figure 11 [[ID=七十四]] Figure 19 [[ID=七十五]] 照]] [[ID=七十六]]

[0139] [[ID=七十七]] Figure 1 [[ID=七十八]] Figure 2 [[ID=七十九]] Figure 18 [[ID=八十]] Figure 18 [[ID=八十一]] [[ID=八十二]]

[0140] [[ID=八十三]] [[ID=八十四]]

[0141] [[ID=八十五]] Figure 2 [[ID=八十六]] Figure 5 [[ID=八十七]] [[ID=八十八]]

[0142] [[ID=八十九]] [[ID=九十]]

[0143] [[ID=九十一]] Figure 2 [[ID=九十二]] Figure 5 [[ID=九十三]] Figure 18 [[ID=九十四]] Figure 18 [[ID=九十五]] [[ID=九十六]]

[0144] [[ID=九十七]] [[ID=九十八]]

[0145] [[ID=九十九]] [[ID=一百]]

[0146] [[ID=一百零一]] [[ID=一百零二]]

[0147] [[ID=一百零三]] Figure 18 [[ID=一百零四]] [[ID=一百零五]]

[0148] [[ID=一百零六]] [[ID=一百零七]]

[0149] [[ID=一百零八]] [[ID=一百零九]]

[0150] [[ID=一百一十]] [[ID=一百一十一]]

[0151] [[ID=一百一十二]] Figure 11 [[ID=一百一十三]] [[ID=一百一十四]]

[0152] [[ID=一百一十五]] Figure 18 [[ID=一百一十六]] [[ID=一百一十七]]

[0153] [[ID=一百一十八]] Figure 18 [[ID=一百一十九]] [[ID=一百二十]]

[0154] [[ID=一百二十一]] [[ID=一百二十二]]

[0155] [[ID=一百二十三]] Figure 3 [[ID=一百二十四]] Figure 9 [[ID=一百二十五]] Figure 18 照]] [[ID=一百二十六]] Figure 18 [[ID=一百二十七]] [[ID=一百二十八]]

[0156] [[ID=一百二十九]] [[ID=一百三十]]

[0157] [[ID=一百三十一]] Figure 18 [[ID=一百三十二]] [[ID=一百三十三]]

[0158] [[ID=一百三十四]] Figure 18 [[ID=一百三十五]] [[ID=一百三十六]]

[0159] 照]] [[ID=一百三十七]] Figure 17 [[ID=一百三十八]] [[ID=一百三十九]]

[0160] [[ID=一百四十]] [[ID=一百四十一]]

[0161] [[ID=一百四十二]] [[ID=一百四十三]]

[0162] [[ID=一百四十四]] [[ID=一百四十五]]

[0163] [[ID=一百四十六]] Figure 5 [[ID=一百四十七]] Figure 18 [[ID=一百四十八]] [[ID=一百四十九]]

[0164] [[ID=一百五十]] Figure 11 [[ID=一百五十一]] [[ID=一百五十二]]

[0165] [[ID=一百五十三]] Figure 17 [[ID=一百五十四]] [[ID=一百五十五]]

[0166] [[ID=一百五十六]] Figure 17 [[ID=一百五十七]] Figure 21 [[ID=一百五十八]] Figure 21 [[ID=一百五十九]] Figure 17 [[ID=一百六十]] [[ID=一百六十一]]

[0167] [[ID=一百六十二]] Figure 21 [[ID=一百六十三]] Figure 17 [[ID=一百六十四]] Figure 21 [[ID=一百六十五]] [[ID=一百六十六]]

[0168] [[ID=一百六十七]] [[ID=一百六十八]]

[0169] [[ID=一百六十九]] [[ID=一百七十]]

[0170] [[ID=一百七十一]] [[ID=一百七十二]]

[0171] [[ID=一百七十三]] [[ID=一百七十四]]

[0172] [[ID=一百七十五]] [[ID=一百七十六]]

[0173] [[ID=一百七十七]] [[ID=一百七十八]]

[0174] [[ID=一百七十九]] [[ID=一百八十]]

[0175] [[ID=一百八十一]] [[ID=一百八十二]]

[0176] [[ID=一百八十三]] [[ID=一百八十四]]

[0177] [[ID=一百八十五]] [[ID=一百八十六]]<000053照9> [[ID=一百八十七]] [[ID=一百八十八]]

[0179] [[ID=一百八十九]] [[ID=一百九十]]

[0180] [[ID=一百九十一]] [[ID=一百九十二]]

[0181] [[ID=一百九十三]] [[ID=一百九十四]]

[0182] [[ID=一百九十五]] [[ID=一百九十六]]

[0183] [[ID=一百九十七]] [[ID=一百九十八]]

[0184] [[ID=一百九十九]] [[ID=二百]]

[0185] [[ID=-百零一]]<000055When the reference voltage generation circuit 60 generates a reference voltage VRC through a bandgap reference circuit, when the power supply voltage VDD decreases to about 1.1V, for example, due to the low voltage of the power supply voltage VDD, the reference voltage VRC generated by the bandgap reference circuit has a negative temperature characteristic.

[0129] As shown in the above formula (12), when VTS > VTS2, the low-temperature side tail current control circuit 70 generates a current IQ by converting the voltage difference between VA1 = VTS as the first voltage and VA2 = VTS2 as the second voltage into a current. The temperature characteristic of the second voltage is different from that of the first voltage. That is, Figure 18 the voltage difference VA1 - VA2 = VTS - VTS2 shown by D1 and D2 is converted into a current IQ. Thus, a current IQ shown by D5 in the low-temperature side temperature range is generated, and the tail current corresponding to this current IQ flows to the low-temperature side differential pair circuit DP. Figure 18

[0130] Therefore, as shown by D5 in Figure 18

[0131] Figure 5 Figure 18 Figure 18

[0132] Figure 18

[0133] Figure 18

[0134] Figure 5 Figure 18 Figure 18

[0135] Figure 18 Figure 18

[0136] Figure 19 Figure 20 Figure 20 Figure 19 Figure 19 Figure 19

[0137] Figure 19 Figure 20

[0138] Figure 11 Figure 19

[0139] Figure 1 Figure 2 Figure 18 Figure 18

[0140]

[0141] Figure 2 Figure 5

[0142]

[0143] Figure 2 Figure 5 Figure 18 Figure 18

[0144]

[0145]

[0146]

[0147] Figure 18

[0148]

[0149]

[0150]

[0151] Figure 11 [[ID=In addition, as shown in the above formula (14), when VTS2 > VTS, the tail current control circuit 70 on the high-temperature side generates a current IQ by converting the voltage difference between VA1 = VTS2 as the first voltage and VA2 = VTS as the second voltage into a current. The temperature characteristic of the second voltage is different from that of the first voltage. That is, VA1 - VA2 = VTS2 - VTS, which is the voltage difference shown by D3 and D4 as Figure 18 is converted into the current IQ. Thus, the current IQ shown by D6 is generated within the temperature range on the high-temperature side, and the tail current corresponding to this current IQ flows to the differential pair circuit DP on the high-temperature side.

[0133] Therefore, as Figure 18 shown by D6, a tail current whose current value becomes the minimum current value, such as zero, at the inflection point temperature T0 of the temperature compensation voltage and increases as the temperature rises from the inflection point temperature T0 flows to the differential pair circuit DP on the high-temperature side. At this time, as shown in the above formula (13), within the temperature range on the high-temperature side where VTS < VTS2, the current IQ in the tail current control circuit 70 on the low-temperature side becomes zero. Therefore, within the temperature range on the high-temperature side, the tail current of the differential pair circuit DP on the low-temperature side does not flow, and it is possible to prevent current from flowing uselessly in the differential pair circuit DP on the low-temperature side.

[0134] Taking Figure 5 as an example, within the temperature range on the high-temperature side, the second tail current control circuit 72 generates a current IQ corresponding to the voltage difference between VA1 = VTS2 and VA2 = VTS. That is, a current IQ as shown by D6 corresponding to the voltage difference between D3 and D4 of Figure 18 is generated. Thus, a tail current IBH corresponding to the current IQ of D6 of Figure 18 flows through the differential pair circuits DPH1 and DPH2 on the high-temperature side. That is, the tail current IBH whose current value increases as the temperature rises from the inflection point temperature T0 flows to the differential pair circuits DPH1 and DPH2 on the high-temperature side. At this time, the current IQ in the first tail current control circuit 71 becomes zero as the minimum current value as shown in the above formula (13), so no tail current IBL flows through the differential pair circuits DPL1 and DPL2 on the low-temperature side. Therefore, within the temperature range on the high-temperature side, it is possible to prevent current from flowing uselessly in the differential pair circuits DPL1 and DPL2 on the low-temperature side.

[0135] In addition, in the above, as the voltages VA1 and VA2 of the tail current control circuit 70, the case where VA1 = VTS and VA2 = VTS2 on the low-temperature side and VA1 = VTS2 and VA2 = VTS on the high-temperature side has been described as an example, but this embodiment is not limited thereto. For example, in Figure 18In the case of a low-temperature voltage, VA1 can be set to VTS, VA2 to VRC, or VA1 to VRC, VA2 to VTS2. Similarly, in the case of a high-temperature voltage, VA1 can be set to VTS2, VA2 to VRC, or VA1 to VRC, VA2 to VTS. In this case, the temperature characteristics of the reference voltage VRC are not limited to... Figure 18 Such a negative temperature characteristic can also be a flat temperature characteristic or a positive temperature characteristic.

[0136] Figure 19 , Figure 20 This is an explanatory diagram about the effect of giving the tail current temperature characteristics. Figure 20 It is Figure 19 The enlarged portion shown in E4. Figure 19 E1 represents the temperature characteristic of the tail current when it lacks strong temperature characteristics, while E3 represents the temperature characteristic of the differential pair circuit DP current ITH when the tail current flows through E1. Additionally, Figure 19 E2 is the temperature characteristic of the tail current when it has strong temperature characteristics, and E4 is the temperature characteristic of the differential pair circuit DP current ITH when the tail current of E2 flows through it.

[0137] like Figure 19 As shown, by making the tail current have a stronger temperature characteristic than E1, as in E2, the current ITH of the differential pair circuit DP can have a steeper temperature characteristic than E3, as in E4. Furthermore, in E1 where the tail current does not have a strong temperature characteristic and in E2 where the tail current has a strong temperature characteristic, near the inflection point temperature T0 at room temperature, such as... Figure 20 As shown in E3 and E4, the current ITH in the differential pair circuit DP flows in different ways.

[0138] For example, as in Figure 11 As explained, the relationship IB = ITH + IER holds true between the currents ITH and IER and the tail current IB. Furthermore, the current IER does not contribute to temperature compensation and is therefore a useless current. Figure 19 E1 and E2 are the tail currents IB, and E3 and E4 are the currents ITH. Therefore, the difference in current between E1 and E3 corresponds to the current IER when the tail current does not have a strong temperature characteristic, while the difference in current between E2 and E4 corresponds to the current IER when the tail current has a strong temperature characteristic. Therefore, as shown in E2, by making the tail current have a strong temperature characteristic, the useless current IER flowing in the differential pair circuit DP can be reduced, thus achieving low power consumption.

[0139] As explained above, Figure 1 , Figure 2As shown, the circuit device 20 of this embodiment includes an oscillation circuit 30, a temperature compensation circuit 40, and a tail current control circuit 70. The oscillation circuit 30 oscillates the oscillator 10 to generate an oscillation signal. The temperature compensation circuit 40 includes a high-order correction circuit 44 that generates a high-order compensation current based on a temperature detection voltage VTS from a temperature detection circuit 50, and a temperature compensation voltage VCP that generates the oscillation frequency of the oscillation signal based on the high-order compensation current. Furthermore, the high-order correction circuit 44 includes a differential pair circuit DP, which controls the tail current via the tail current control circuit 70, generating a temperature compensation current based on the temperature detection voltage VTS. The tail current control circuit 70 controls the tail current of the differential pair circuit DP in a manner that minimizes the current value at the inflection point temperature of the temperature compensation voltage and increases according to temperature changes from the inflection point temperature. That is, as... Figure 18 As shown in D5, D6, and equations (12), (13), (14), and (15), the tail current of the differential pair circuit DP is controlled in such a way that the current value becomes the minimum current value, for example, zero, at the inflection point temperature (T0) and increases according to the temperature change from the inflection point temperature. For example, as Figure 18 As shown in D5, the tail current is controlled in such a way that the current value increases as the temperature decreases from the inflection point temperature (T0), or as shown in D6, the tail current is controlled in such a way that the current value increases as the temperature increases from the inflection point temperature.

[0140] Thus, according to this embodiment, in the differential pair circuit DP that generates the high-order compensation current in the high-order correction circuit 44 and generates the temperature compensation current, the tail current is controlled in such a way that the tail current is at its minimum value at the inflection point temperature. This significantly reduces the high-order compensation current flowing at the inflection point temperature, making it easier to match the characteristics of the high-order compensation current and adjust the inflection point. Furthermore, by controlling the tail current of the differential pair circuit DP to increase according to the temperature change from the inflection point temperature, the temperature characteristics of the temperature compensation current generated by the differential pair circuit DP can be made to be steeper. Therefore, for example, when the power supply voltage is lowered, a more appropriate high-order compensation current can be generated, and the power consumption of the circuit device 20 can be reduced.

[0141] In addition, such as Figure 2 , Figure 5As shown, the higher-order correction circuit 44 includes a first compensation circuit 47 and a second compensation circuit 48. Furthermore, the first compensation circuit 47 has a differential pair circuit DPL (DPL1, DPL2) for the low-temperature side as a differential pair circuit, through which a temperature compensation current (IL) for the low-temperature side is generated. Additionally, the second compensation circuit 48 has a differential pair circuit DPH (DPH1, DPH2) for the high-temperature side as a differential pair circuit, through which a temperature compensation current (IH) for the high-temperature side is generated.

[0142] Thus, within the low-temperature side temperature range, a higher-order compensation current can be generated through the temperature compensation current generated by the differential pair circuit DPL of the first compensation circuit 47. Within the high-temperature side temperature range, a higher-order compensation current can be generated through the temperature compensation current generated by the differential pair circuit DPH of the second compensation circuit 48. Therefore, within each temperature range on both the low-temperature and high-temperature sides, using the tail current whose current value becomes the minimum at the inflection point temperature and increases according to temperature changes, currents for generating higher-order compensation currents can be generated through each differential pair circuit on both the low-temperature and high-temperature sides.

[0143] In addition, such as Figure 2 , Figure 5 As shown, the tail current control circuit 70 includes a first tail current control circuit 71 and a second tail current control circuit 72. Furthermore, as... Figure 18 As shown in D5, equations (12) and (13) above, the first tail current control circuit 71 controls the first tail current (IBL) of the differential pair circuit DPL in such a way that the current value is the minimum current value at the inflection point temperature (T0) and increases as the temperature decreases from the inflection point temperature. Furthermore, as... Figure 18 As shown in D6, equations (14) and (15) above, the second tail current control circuit 72 controls the second tail current (IBH) of the differential pair circuit DPH in such a way that the current value is the minimum current value at the inflection point temperature (T0) and increases as the temperature rises from the inflection point temperature.

[0144] Thus, within the low-temperature side temperature range, the differential pair circuit DPL, which has a first tail current flowing to the low-temperature side, such that its current value is minimum at the inflection point temperature and increases as the temperature decreases from the inflection point temperature, can generate a current for generating a higher-order compensation current on the low-temperature side. This enables appropriate temperature compensation within the low-temperature side temperature range. Furthermore, within the high-temperature side temperature range, the differential pair circuit DPH, which has a second tail current flowing to the high-temperature side, such that its current value is minimum at the inflection point temperature and increases as the temperature increases from the inflection point temperature, can generate a current for generating a higher-order compensation current on the high-temperature side. This also enables appropriate temperature compensation within the high-temperature side temperature range.

[0145] Furthermore, the first tail current control circuit 71 controls the first tail current in such a way that the current value becomes the minimum current value when the temperature is higher than the inflection point temperature. The second tail current control circuit 72 controls the second tail current in such a way that the current value becomes the minimum current value when the temperature is lower than the inflection point temperature. That is, a first tail current with a low-temperature side, as shown in D5, is generated when the temperature is lower than the inflection point temperature (T0), but the first tail current on the low-temperature side becomes the minimum current value when the temperature is higher than the inflection point temperature. Similarly, a second tail current with a high-temperature side, as shown in D6, is generated when the temperature is higher than the inflection point temperature, but the second tail current on the high-temperature side becomes the minimum current value when the temperature is lower than the inflection point temperature.

[0146] Thus, when the temperature is higher than the inflection point, the first tail current in the differential pair circuit DPL on the low-temperature side becomes the minimum current value. Therefore, during temperature compensation on the high-temperature side, it is possible to suppress the flow of unwanted current in the differential pair circuit DPL on the low-temperature side. Furthermore, when the temperature is lower than the inflection point, the second tail current in the differential pair circuit DPH on the high-temperature side becomes the minimum current value. Therefore, during temperature compensation on the low-temperature side, it is possible to suppress the flow of unwanted current in the differential pair circuit DPH on the high-temperature side. This enables the circuit device 20 to achieve low power consumption.

[0147] Furthermore, in this embodiment, the value of the first tail current increases linearly as the temperature decreases from the inflection point temperature, and the value of the second tail current increases linearly as the temperature increases from the inflection point temperature. For example, as... Figure 18 As shown in D5, the value of the first tail current (IBL) on the low-temperature side increases with a primary characteristic as the temperature decreases from the inflection point temperature. Furthermore, as shown in D6, the value of the second tail current (IBH) on the high-temperature side increases with a primary characteristic as the temperature increases from the inflection point temperature.

[0148] Thus, the value of the first tail current on the low-temperature side increases monotonically with the slope of the primary characteristic as the temperature decreases from the inflection point temperature, while the value of the second tail current on the high-temperature side increases monotonically with the slope of the primary characteristic as the temperature increases from the inflection point temperature. Therefore, based on the first and second tail currents with primary temperature characteristics, the differential pair circuit DPL on the low-temperature side and the differential pair circuit DPH on the high-temperature side can generate temperature compensation currents with steeper temperature characteristics.

[0149] In addition, the minimum current value of the tail current is, for example, zero. That is, the tail current control circuit 70 controls the tail current in such a way that the current value becomes zero at the inflection point temperature, and the current value increases according to the temperature change from the inflection point temperature.

[0150] In this way, by making the tail current value in the differential pair circuit DP zero at the inflection point temperature, it is easy to match the characteristics of the high-order compensation current and adjust the inflection point. In addition, it is possible to suppress unwanted tail current flowing through the differential pair circuit DP, thus achieving low power consumption of the circuit device 20.

[0151] In addition, such as Figure 11 As explained above, the tail current control circuit 70 generates a current IQ to control the tail current by converting the voltage difference between voltage VA1 (a first voltage) and voltage VA2 (a second voltage) into a current. The temperature characteristics of the second voltage are different from those of voltage VA1. That is, as shown in equations (10), (12), and (14) above, the tail current control circuit 70 generates a current IQ that converts the voltage difference between voltage VA1 and voltage VA2, i.e., VA1-VA2, into a current.

[0152] Thus, as Figure 18 As shown in D1, D2, D3, and D4, the tail current generated by the temperature change from the inflection point temperature increases with the voltage difference between voltages VA1 and VA2, i.e., VA1-VA2. Furthermore, the differential pair circuit DP generates a temperature compensation current through this tail current with strong temperature characteristics, thus enabling the generation of an appropriate high-order compensation current even when the power supply voltage is low.

[0153] Furthermore, the voltage difference between voltage VA1 (the first voltage) and voltage VA2 (the second voltage) becomes zero at the inflection point temperature. For example, Figure 18 As shown, when VA1 = VTS and VA2 = VTS2 on the low-temperature side, VA1 - VA2 = VTS - VTS2 becomes zero at the inflection point temperature. Conversely, when VA1 = VTS2 and VA2 = VTS on the high-temperature side, VA1 - VA2 = VTS2 - VTS becomes zero at the inflection point temperature.

[0154] Thus, at the inflection point temperature, the voltage difference between voltages VA1 and VA2, i.e., VA1-VA2, becomes zero. Consequently, the current IQ generated by converting this voltage difference into current also becomes zero. Therefore, the tail current flowing to the differential pair circuit DP can also be set to zero at the inflection point temperature, enabling the matching of high-order compensation current characteristics, facilitating inflection point adjustment, and reducing power consumption.

[0155] In addition, such as Figure 3 , Figure 9 As shown, the temperature compensation circuit 40 includes a primary correction circuit 43 that performs one temperature compensation. Furthermore, as... Figure 18As explained in equations (12) to (15) above, the voltage VA1, which is the first voltage, is one of the following: the temperature detection voltage VTS, the voltage VTS2 output by the operational amplifier OPD2 of the primary correction circuit 43, or the reference voltage VRC used for temperature compensation. Furthermore, the voltage VA2, which is the second voltage, is a voltage different from one of the above voltages: the temperature detection voltage VTS, the voltage VTS2, or the reference voltage VRC. For example, in equations (12) and (13) above, VA1 = VTS, VA2 = VTS2; in equations (14) and (15) above, VA1 = VTS2, VA2 = VTS. In this case, either voltage VA1 or VA2 could also be... Figure 18 The reference voltage VRC used for temperature compensation is shown.

[0156] In this way, by converting the voltage difference between the temperature detection voltage VTS, the voltage VTS2 output from the operational amplifier OPD2 of the primary correction circuit 43, and the reference voltage VRC used for temperature compensation into current, a current IQ can be generated to control the tail current of the differential pair circuit DP. Therefore, the tail current of the differential pair circuit DP can be effectively controlled using the temperature detection voltage VTS, voltage VTS2, and reference voltage VRC.

[0157] Furthermore, voltage VA1, which is the first voltage, and voltage VA2, which is the second voltage, have primary temperature characteristics. For example, when... Figure 18 When the temperature sensing voltage VTS, voltage VTS2, and reference voltage VRC are used as voltages VA1 and VA2, the temperature sensing voltage VTS, voltage VTS2, and reference voltage VRC may have primary temperature characteristics, such as negative or positive primary temperature characteristics.

[0158] Thus, when current IQ is generated by converting the voltage difference (VA1-VA2) between voltages VA1 and VA2 into current, as follows: Figure 18 As shown in D5 and D6, a current IQ that varies linearly with temperature can be generated. Moreover, by using such a current IQ, the tail current that varies linearly with temperature can be directed to the differential pair circuit DP.

[0159] In addition, such as Figure 17As shown, the tail current control circuit 70 includes a differential section 74 and an output section 75. The differential section 74 includes a bipolar transistor TA4 controlled by voltage VA1 and a bipolar transistor TA3 controlled by the output of the output section 75 as a differential pair. Bipolar transistor TA4 is the first transistor, and bipolar transistor TA3 is the second transistor. The output of the output section 75 is node NA4. Furthermore, the output section 75 is located between node VDL (which is a power supply node) and node NA4, and includes a transistor TA6 controlled by the output of the differential section 74, and a resistor RA located between node NA4 and the input node of voltage VA2. Node NA4 is the first node. The output of the differential section 74 is node NA2, for example, the output voltage VAQ. Additionally, the output section 75 may include: a transistor TA7 located between node VDL and node NA5, controlled by the output of the differential section 74; and a bipolar transistor TA8 located between node NA5 and node VSS, with its base and collector connected to node NA5.

[0160] According to the tail current control circuit 70 with this structure, the voltage of node NA4, which is the first node, is set to voltage VA1 through the virtual grounding of the differential section 74. Therefore, the current corresponding to the voltage difference between voltage VA1 and voltage VA2, i.e., (VA1-VA2), can flow to the resistor RA. Furthermore, the tail current of the differential pair circuit DP can be controlled by the current IQ corresponding to the current flowing to the resistor RA.

[0161] 3. Variations

[0162] As described above, the circuit device 20 and the oscillator 4 of this embodiment have been explained, but this embodiment is not limited thereto and various modifications can be implemented.

[0163] For example in Figure 5 , Figure 18 The following description focuses on the case where the tail current control method of this embodiment increases the current value according to the temperature change from the inflection point temperature within both the low-temperature and high-temperature temperature ranges. However, the tail current control method of this embodiment described above can also be implemented within only one temperature range, or within three or more temperature ranges.

[0164] Furthermore, the structure of the differential pair circuit DP is not limited to Figure 11 The structure described herein can be modified in various ways. For example, as a differential pair transistor, a pnp bipolar transistor can be used instead of an npn bipolar transistor. Alternatively, an N-type MOS transistor or a P-type MOS transistor can be used instead of a bipolar transistor. Furthermore, as a current source transistor, a MOS transistor can be used instead of a bipolar transistor.

[0165] Furthermore, the structure of the tail current control circuit 70 is not limited to Figure 17 The structure described herein can be modified in various ways. For example, the transistor serving as the differential pair in the differential section 74 can be a pnp bipolar transistor instead of an npn bipolar transistor. Alternatively, an N-type MOS transistor or a P-type MOS transistor can be used instead of a bipolar transistor. Furthermore, the transistor serving as the current source can also be a bipolar transistor instead of a MOS transistor.

[0166] Furthermore, the structure of the output section 75 of the tail current control circuit 70 is not limited to... Figure 17 The structure shown. For example, Figure 21 Other structural examples of the tail current control circuit 70 are shown. Figure 21 Transistors TA9, TA10, and TA11 are used to replace... Figure 17 Transistors TA6 and TA7 are connected in series. Transistors TA10 and TA9 are connected in series between node NA4, which is one end of resistor RA. Furthermore, transistor TA11 and bipolar transistor TA8 are connected in series between node VDL and node VSS. The gate of transistor TA9 is connected to node NA2, which serves as the output of differential unit 74. The gates of transistors TA10 and TA11 are connected to node NA6, which is between transistors TA10 and TA9. The drain of transistor TA11 is connected to node NA5, which connects the collector and base of bipolar transistor TA8.

[0167] exist Figure 21 In the middle section, the output section 75 is changed to a cascaded structure, operating as a two-stage amplifier, thus enabling it to achieve a higher efficiency than... Figure 17 High gain. Additionally, in Figure 21 In the structure, in order to ensure the gate-source voltage VGS of the cascade stage that serves as the output section 75, it is necessary to increase the voltage range of voltage VA1 and the voltage difference between the power supply voltage VDL.

[0168] As explained above, the circuit arrangement of this embodiment includes: an oscillation circuit that oscillates an oscillator to generate an oscillation signal; a temperature compensation circuit that includes a high-order correction circuit that generates a high-order compensation current based on a temperature detection voltage from a temperature detection circuit, and a temperature compensation voltage that generates the oscillation frequency of the oscillation signal based on the high-order compensation current; and a tail current control circuit. The high-order correction circuit includes a differential pair circuit that controls the tail current via the tail current control circuit, generating a temperature compensation current based on the temperature detection voltage. Furthermore, the tail current control circuit controls the tail current in such a way that the current value is at the inflection point temperature of the temperature compensation voltage and increases according to temperature changes from the inflection point temperature.

[0169] According to this embodiment, the tail current is controlled such that the current value is minimized at the inflection point temperature, thus reducing the high-order compensation current flowing at the inflection point temperature. Furthermore, by controlling the tail current such that the current value increases according to the temperature change from the inflection point temperature, the temperature characteristic of the temperature compensation current generated by the differential pair circuit becomes a steeper temperature characteristic.

[0170] Furthermore, in this embodiment, the high-order correction circuit may include: a first compensation circuit having a first differential pair circuit for the low-temperature side as a differential pair circuit, generating a current for temperature compensation on the low-temperature side through the first differential pair circuit; and a second compensation circuit having a second differential pair circuit for the high-temperature side as a differential pair circuit, generating a current for temperature compensation on the high-temperature side through the second differential pair circuit.

[0171] In this way, within the temperature range of the low-temperature side, a higher-order compensation current can be generated by the temperature compensation current generated by the differential pair circuit of the first compensation circuit, and within the temperature range of the high-temperature side, a higher-order compensation current can be generated by the temperature compensation current generated by the differential pair circuit of the second compensation circuit.

[0172] Furthermore, in this embodiment, the tail current control circuit may include a first tail current control circuit that controls the first tail current of the first differential pair circuit in such a way that the current value is at the inflection point temperature of the temperature compensation voltage and increases as the temperature decreases from the inflection point temperature. Additionally, the tail current control circuit may also include a second tail current control circuit that controls the second tail current of the second differential pair circuit in such a way that the current value is at the inflection point temperature of the temperature compensation voltage and increases as the temperature increases from the inflection point temperature.

[0173] This allows for appropriate temperature compensation within the low-temperature range and appropriate temperature compensation within the high-temperature range.

[0174] Alternatively, in this embodiment, the first tail current control circuit can control the first tail current in such a way that the current value becomes the minimum current value when the temperature is higher than the inflection point temperature, and the second tail current control circuit can control the second tail current in such a way that the current value becomes the minimum current value when the temperature is lower than the inflection point temperature.

[0175] In this way, when performing temperature compensation on the high-temperature side, it is possible to suppress the flow of useless current in the differential pair circuit on the low-temperature side, and when performing temperature compensation on the low-temperature side, it is possible to suppress the flow of useless current in the differential pair circuit on the high-temperature side.

[0176] Alternatively, in this embodiment, the current value of the first tail current may increase with a linear characteristic as the temperature decreases from the inflection point temperature, and the current value of the second tail current may increase with a linear characteristic as the temperature increases from the inflection point temperature.

[0177] In this way, based on the first tail current and the second tail current, which have primary temperature characteristics, the differential pair circuit on the low temperature side and the differential pair circuit on the high temperature side can generate a temperature compensation current with a steeper temperature characteristic.

[0178] In addition, in this embodiment, the minimum current value can be zero.

[0179] This makes it easy to match the characteristics of high-order compensation current and adjust the inflection point, or to achieve low power consumption in circuit devices.

[0180] In addition, in this embodiment, the tail current control circuit may generate a current to control the tail current by converting the voltage difference between the first voltage and a second voltage with temperature characteristics different from the first voltage into a current.

[0181] In this way, by changing the temperature from the inflection point temperature, a tail current can be generated whose current value increases as the voltage difference between the first voltage and the second voltage increases.

[0182] In addition, in this embodiment, the voltage difference between the first voltage and the second voltage can also become zero at the inflection point temperature.

[0183] Thus, at the inflection point temperature, the voltage difference between the first voltage and the second voltage becomes zero, and consequently, the current value generated by converting this voltage difference into current can also become zero.

[0184] Furthermore, in this embodiment, the temperature compensation circuit may include a primary correction circuit for performing one temperature compensation, where the first voltage is one of the temperature detection voltage, the voltage output by the operational amplifier of the primary correction circuit, and the reference voltage for temperature compensation. Additionally, the second voltage may be a voltage different from the first voltage among the temperature detection voltage, the voltage output by the operational amplifier of the primary correction circuit, and the reference voltage for temperature compensation.

[0185] In this way, the tail current of the differential pair circuit can be effectively controlled by utilizing the temperature detection voltage, the voltage output of the operational amplifier in the primary correction circuit, and the reference voltage used for temperature compensation.

[0186] In addition, in this embodiment, the first voltage and the second voltage may also have a primary temperature characteristic.

[0187] In this way, the tail current, which changes linearly with respect to temperature, can flow to the differential pair circuit.

[0188] In addition, in this embodiment, the tail current control circuit may include a differential section and an output section. The differential section includes a first transistor controlled by a first voltage and a second transistor controlled by the output of the output section as a differential pair. Furthermore, the output section may include: a transistor disposed between the power supply node and the first node, controlled by the output of the differential section; and a resistor disposed between the first node and the input node of the second voltage.

[0189] According to the tail current control circuit with this structure, the voltage of the first node is set to the first voltage by the virtual grounding of the differential part. Therefore, the current corresponding to the voltage difference between the first voltage and the second voltage flows to the resistor, and the tail current of the differential pair circuit can be controlled by the current corresponding to the current flowing to the resistor.

[0190] Furthermore, the oscillator of this embodiment includes the circuit arrangement and oscillator described above.

[0191] Furthermore, while this embodiment has been described in detail above, those skilled in the art will readily understand that various modifications can be made without substantially departing from the new aspects and effects of this disclosure. Therefore, all such modifications are included within the scope of this disclosure. For example, a term that is described at least once in the specification or drawings along with a different, broader, or synonymous term can be replaced with that different term anywhere in the specification or drawings. Moreover, all combinations of this embodiment and its modifications are also included within the scope of this disclosure. Furthermore, the structure, operation, etc., of the circuit device, oscillator, etc., are not limited to those described in this embodiment, and various modifications can be implemented.

Claims

1. A circuit device, characterized in that, The circuit device includes: An oscillating circuit, which causes an oscillator to oscillate and generates an oscillating signal; A temperature compensation circuit includes a high-order correction circuit that generates a high-order compensation current based on a temperature detection voltage from a temperature detection circuit, and a temperature compensation voltage that generates the oscillation frequency of the oscillation signal based on the high-order compensation current; and Tail current control circuit, The higher-order correction circuit includes a differential pair circuit, which controls the tail current through the tail current control circuit to generate a temperature compensation current based on the temperature detection voltage. The tail current control circuit controls the tail current in such a way that the current value is at the inflection point temperature of the temperature compensation voltage to be the minimum current value and increases according to the temperature change from the inflection point temperature.

2. The circuit device according to claim 1, characterized in that, The higher-order correction circuit includes: The first compensation circuit has a first differential pair circuit for the low-temperature side as the differential pair circuit, and generates the temperature compensation current for the low-temperature side through the first differential pair circuit. as well as The second compensation circuit has a second differential pair circuit for the high-temperature side as the differential pair circuit, and generates the temperature compensation current for the high-temperature side through the second differential pair circuit.

3. The circuit device according to claim 2, characterized in that, The tail current control circuit includes: A first tail current control circuit controls the first tail current of the first differential pair circuit in such a way that the current value becomes the minimum current value at the inflection temperature of the temperature compensation voltage and increases as the temperature decreases from the inflection temperature. as well as The second tail current control circuit controls the second tail current of the second differential pair circuit in such a way that the current value becomes the minimum current value at the inflection point temperature of the temperature compensation voltage and increases as the temperature rises from the inflection point temperature.

4. The circuit device according to claim 3, characterized in that, The first tail current control circuit controls the first tail current in such a way that the first tail current becomes the minimum current value when the temperature is higher than the inflection point temperature. The second tail current control circuit controls the second tail current in such a way that the second tail current becomes the minimum current value when the temperature is lower than the inflection point temperature.

5. The circuit device according to claim 3, characterized in that, The value of the first tail current increases linearly as the temperature decreases from the inflection point temperature. The value of the second tail current increases with increasing temperature from the inflection point temperature in a linear manner.

6. The circuit device according to claim 1, characterized in that, The minimum current value is zero.

7. The circuit device according to claim 1, characterized in that, The tail current control circuit generates a current to control the tail current by converting the voltage difference between the first voltage and the second voltage into a current. The temperature characteristics of the second voltage are different from those of the first voltage.

8. The circuit device according to claim 7, characterized in that, The voltage difference between the first voltage and the second voltage becomes zero at the inflection point temperature.

9. The circuit device according to claim 7, characterized in that, The temperature compensation circuit includes a primary correction circuit that performs one temperature compensation. The first voltage is one of the following: the temperature detection voltage, the voltage output by the operational amplifier of the primary correction circuit, and the reference voltage used for temperature compensation. The second voltage is a voltage that is different from the first voltage among the temperature detection voltage, the voltage output by the operational amplifier of the primary correction circuit, and the reference voltage used for temperature compensation.

10. The circuit device according to claim 7, characterized in that, The first voltage and the second voltage have primary temperature characteristics.

11. The circuit device according to claim 7, characterized in that, The tail current control circuit includes a differential section and an output section. The differential section includes a first transistor controlled by the first voltage and a second transistor controlled by the output of the output section as a differential pair. The output section includes: A transistor, disposed between a power supply node and a first node, is controlled by the output of the differential unit; and A resistor is disposed between the first node and the input node of the second voltage.

12. An oscillator, characterized in that, The oscillator comprises the circuit arrangement as described in any one of claims 1 to 11 and the oscillator.

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