JP7322004B2 - Temperature stabilizer with accelerated response to power supply fluctuations - Google Patents

Description

The present invention accelerates the transient response of the device to power supply fluctuations, shortening the time required for the temperature of the device to return to its control set point, resulting in undesirable transient changes in key performance parameters of the device. It relates to miniaturized temperature stabilized electronic devices.

A key performance parameter of many electronic devices is often dependent on the ambient temperature. For example, the frequency of the signal generated by an electronic oscillator depends on multiple external parameters such as ambient temperature, supply voltage, and mechanical acceleration, and frequency instability is due to ambient temperature changes being particularly pronounced. are doing.

A number of techniques have been developed to reduce the sensitivity of key performance parameters of electronic devices to variations in ambient temperature. One such technique is device temperature stabilization, where the temperature sensitive portion of an electronic device is placed in a temperature stable environment to reduce the effects of ambient temperature fluctuations.

One example of temperature stabilized electronics is an oven controlled electronic oscillator. In an oven controlled oscillator (OCO), the temperature of the equipment is controlled and maintained at a predetermined level, usually set a few degrees above the maximum operating temperature of the equipment, so that the temperature fluctuations of the oscillator match those of the ambient temperature. As a result, the stability of the output frequency is improved. Examples of oven-controlled oscillator devices include oven-controlled crystal oscillators (OCXO), including oscillator circuits with crystal resonators, oven-controlled MEMS, including oscillator circuits with microelectromechanical system (MEMS) resonators. oscillators (OCMO), oven controlled SAW oscillators (OCSO) including oscillator circuits comprising surface acoustic wave (SAW) resonators, and the like.

Closed-loop temperature control techniques are often implemented to maintain a stable device assembly temperature within the temperature stabilizer. The diagram of FIG. 1 (Prior Art) provides an example of such a control loop. As shown in FIG. 1, the temperature of an equipment assembly 1 is sensed by a temperature sensor 2, the sensed temperature value (“equipment assembly temperature”) is compared to a desired temperature value (“setpoint”), and a temperature error value is calculated as the difference between the set point and the actual device assembly temperature value, the temperature error is then processed in the error processing block 3 and at the output of the error processing block 3 one heater 4 or several heaters 4 to minimize the temperature error value so that the temperature of the device is closer to the set point.

Any of a number of known control algorithms can be used within the error processing block. For example, a proportional control algorithm can be used, in which the output of the error processing block (i.e., the heater control signal) is arranged to be proportional to the temperature error,
_SHC = _KP ^* ΔT (1)
where _SHC is the value of the heater control signal, _KP is the proportional control factor (also known as proportional gain), and ΔT is the temperature error value (i.e., the desired temperature "setpoint" value and the actual temperature value of the device assembly). Depending on the particular circuit topology, the heater control signal can be either voltage signal V _HC or current signal I _HC .

From expression (1) it follows that the proportional control algorithm makes the non-zero temperature error, often called "offset", permanent. In fact, as soon as the temperature error reaches a zero value (i.e., the device assembly temperature equals the desired "setpoint" value), the value of the heater control signal _{S_HC} also goes to zero, which in turn causes the device The assembly temperature drifts away from the desired "setpoint" temperature. Assuming the proportional gain value _KP is set correctly and the control loop is stable, steady state is reached and the _SHC and ΔT values are stable and non-zero, i.e. a permanent temperature "offset". occurs. To eliminate, or at least minimize, unwanted "offsets," the proportional control method can be enhanced by adding a constant term to the control expression,
_SHC = _KP ^* ΔT+ _CHC (2)
where _CHC is an added heater control constant term.

From expression (2), the constant control term _CHC , when set correctly, can actually eliminate the offset error, but the value of the offset error is only for one particular value of ambient temperature. It will be optimal.

To match the additional term to the full operating range of ambient temperature, the additional term can be generated as the time integral of the temperature error ΔT, such a control algorithm can be expressed in the following expression:
_SHC = K _P ^* ΔT + K _I ^* ∫ΔT ^* ∂t (3)
is known as the proportional integral (PI) and function according to where K _P is the proportional gain and
ΔT is the temperature error value,
_KI is the integral gain,
∂t indicates the time integration.

The integration process K _I ^* ∫ΔT ^* ∂t in expression (3) replaces the constant term _CHC in expression (2), and the integration process is automatically adjusted according to the temperature error value ΔT. It represents a term that Due to the integral nature of the integration process, the PI controller's integration process is slow in time, ie, it takes a significant amount of time for the integration process to have maximum effect.

In addition to proportional and proportional integral, other known control algorithms can be used to control the temperature stabilizer assembly temperature. The important point is that the heater control signal _SHC in any such algorithm has only one variable - the temperature error:
S _HC =f(ΔT) (4)
is generated as a function of

One implication of expression (4) is that the control algorithm does not directly take into account changes in power supply levels. This is because if the supply voltage of the temperature stabilization device changes, this change causes a change in the amount of power consumed in the heater(s), resulting in a change in device assembly temperature and temperature error values. It means to come into being. It will take a considerable amount of time for the temperature error deviation to be processed by the temperature control loop and the resulting processing to take effect. In the case of PI control, the change in ΔT is finally but only corrected after a certain period of time, during which time (a) the changing ΔT value is corrected by the integrator K _i ^* ∫ΔT ^* ∂t and (b) the time required for the device assembly to acquire the required temperature, where period (b) is the magnitude of the thermal mass presented by the temperature stabilizer assembly. depends on

Another implication of a change in power supply voltage level is that the power dissipated in the circuits and components of the temperature stabilizer other than the heater also changes. This power consumption also contributes to the heating of the device assembly, so that changes in power consumption add to the temperature error. Again, due to the nature of the integral control process and the thermal mass of the device, the temperature control loop of the prior art temperature stabilization device "take care" of this change, albeit finally, but only after a period of time. (process)”.

It is an object of the present invention to reduce the time period required for the temperature of the temperature stabilizer to return to the setpoint after a power supply voltage change to reduce the undesirable effects of temperature disturbances on key performance parameters of the temperature stabilizer. The object is to provide a technique that can be shortened, or at least to provide an alternative if the technique for reducing transient effects caused by power supply voltage changes in the temperature stabilizer is not improved. For example, in an oven controlled oscillator (OCO) system, use of the techniques of the present invention can reduce the amount of time the system experiences transient temperature disturbances as a result of power supply fluctuations, and reduce the absolute value of the transient temperature disturbances. , thereby shortening and reducing the variation in the output frequency produced by the OCO device.

As used in this specification and claims, the term "comprising" means "consisting of at least a portion of." When interpreting each statement in the claims, there may be additional features, or features beyond those that follow this term.Related terms such as "comprise" and "comprises" should be interpreted in the same way.

In a first aspect of the invention, the invention presents a temperature stabilizing device that can be powered by a mains voltage source, the device comprising a heater circuit for heating the device assembly and generating a heater control signal. a temperature control circuit arranged to control the amount of power consumed in the heater circuit, the heater control signal configured to be dependent on the power supply voltage level, the electronic configured to be dynamically adjusted.

In at least some embodiments, the temperature control circuit controls the amount of power consumed in the heater circuit to keep the device assembly temperature within up to ±5% of the device's intended operating ambient temperature range, more preferably It is arranged to be maintained within a maximum of ±1%, more preferably within a maximum of ±0.01%.

In at least some embodiments, the heater control signal is arranged to be electronically adjusted for changes in the power supply voltage level not exceeding ±10%, more preferably ±5%, more preferably ±1%. be done.

In a second aspect of the invention, in the temperature stabilization device described above, the electronic circuit is arranged to reduce the heater control signal before it is applied to the heater circuit or to the heater driver circuit. .

As such, the present invention has two main aspects.

I. In a first aspect of the invention, the additional circuitry of the on-temperature stabilizer has the following functions: (a) to detect the power supply voltage level; and (b) to detect the detected power supply voltage as well as the temperature error value. It is arranged to generate heater control signals that are also value dependent. In other words, for the temperature stabilization device of the present invention, expression (4) above becomes the following expression:
_SHC =f(ΔT, _Vs ) (5)
be replaced by
where _SHC is the value of the heater control signal;
ΔT is the temperature error value,
_VS is the power supply voltage value.

An advantage of generating the heater control signal as a function of both temperature error and power supply voltage is that if the power supply voltage changes, the heater power can be adjusted accordingly by the control algorithm to maintain the required amount of heater power. maintains a stable device assembly temperature over the entire temperature range, and further, because heater control signal adjustments are made electronically, such adjustments occur immediately after a power supply voltage change to allow the temperature control loop to bring the device temperature to the desired set point. much more quickly than over the period that would have been necessary to The heater control signal generated according to expression (5) can be said to be "power supply compensated."

II. In a second aspect of the invention, yet another additional circuit is introduced to further accelerate the transient response of the temperature stabilizer to power supply changes.

In temperature stabilized electronics, power is dissipated not only in the heater(s), but also in every other electronic circuit and component of the device. For example, in OCO devices, power consumption also occurs in constant voltage circuits, oscillator circuits, output buffer circuits, and the like. This internal power consumption causes the device to heat up further, ie the device is heated in addition to being heated by the heater(s). At high ambient temperatures, the temperature dependent heater power will be small and the internal power consumption will match or exceed the heater power.

If the power supply voltage level changes, the heater power can be adjusted without any appreciable delay using the technique described in the first aspect of the invention. However, internal power consumption changes will also occur, and temperature errors caused by such changes are sometimes implemented by the temperature control loop, with delays associated with the thermal mass of the device. It will not be corrected as quickly as it will have to be corrected with a delay associated with the nature of the control algorithm used.

To accelerate the response of the temperature stabilizer to changes in internal power consumption due to changes in power supply voltage, embodiments introduce additional circuitry to subtract a small amount of Subtract the power correction heater control signal. This is further explained with reference to FIGS. 2 and 3. FIG. At steady state, the temperature stabilization device assembly temperature is stable, and the device assembly temperature stability is achieved by heating the device assembly to compensate for the heat lost to the ambient environment. As explained above and shown in FIG. 2, the heating of the temperature stabilizer is provided by a heater consuming power P _H1 and by an internal power consumption P _D .
_PΣ = P _H1 + P _D (6)
where P _Σ is the total power heating the temperature stabilizer,
_PH1 is the power consumed in the heater(s);
_PD is the internal power consumption.

In conventional temperature stabilizers, both the _PH1 and _PD values are dependent on the power supply voltage, and when the power supply voltage changes, both the _PH1 and _PD change and the temperature error is handled by the temperature control loop. will be minimized by the temperature control loop after a period of time due to the thermal mass of the device.

In a temperature stabilization device implemented according to the first aspect of the invention, when the supply voltage changes, the heater power P _H1 is maintained by the additional circuitry described in part I of this specification, i.e. the heater control Signal _SHC is power supply compensated and adjusts on the fly to accommodate power supply voltage changes and heater power is maintained at the level required to maintain the required device temperature. However, another component of the total power heating the temperature stabilizer--the internal power consumption P _D --will also change following supply voltage changes and take time to be corrected by the temperature control loop. A temperature error occurs. To further improve the response time to changes in power supply voltage, the heating arrangement is modified according to the second aspect of the invention and shown in FIG.

In this arrangement, a small amount of power supply correction heater control signal is subtracted before the signal is applied to the heater(s) or to the heater driver circuit, such that the amount of subtraction corresponds to the amount of internal power dissipation _PD . do. This is presented to the heater control loop as if the heater control loop also controls the internal power consumption, thereby instantaneously adjusting the internal power consumption on power supply changes with the technique described in Part I of this invention. can be corrected.

For simplicity of concept description, assuming that the amount of heater control signal subtraction corresponds to the amount of internal power consumption P _D , the total heating power in the device shown in FIG.
P _Σ = (P _H2 - P _D ) + P _D (7)
is represented by
Since the total amount of power required to maintain a stable OCO temperature is the same as in the arrangements shown in FIGS. 2 and 3, the following expressions hold:
P _H1 +P _D =(P _H2 −P _D )+P _D (8)
this is,
P _H2 =P _H1 +P _D (9)
means

As such, the arrangement of FIG. 3, and in accordance with the second aspect of the present invention, provides a small amount of power supply correction heater control signal that is applied to the heater(s) or to the heater driver circuit. By subtracting before , the heater power demanded by the control loop is increased, and since the control loop demand is generated using the technique disclosed as the first aspect of the invention, The total heating power within the temperature stabilizer is electronically compensated for power supply changes and reacts to such changes much more quickly than conventional temperature stabilizers.

A more detailed description of the second aspect of the invention is presented below as applied to an oven controlled oscillator (OCO) device.

Many modern OCO devices comprise a voltage regulator circuit that produces a power supply voltage that is characterized by a higher stability than an externally supplied power supply voltage that is not regulated to a constant voltage.

The total power _PΣ dissipated in the OCO assembly is the sum of the power P _H1 dissipated in the heater(s) of the OCO and the power P _D dissipated in all other circuits internal to the OCO. .
P _Σ = P _H1 + P _D

The internal power consumption P _D is defined as the power consumed by circuits powered by the internal constant voltage regulated power supply and drawing the constant voltage regulated power supply current _Ir , and the constant power supply drawing the _{current Iur} of the power supply not regulated to a constant voltage It can be divided into the power consumed by circuits powered by a power supply that is not regulated to voltage. The current I _r is independent of the external supply voltage V, as it is drawn by a circuit operating on an internal constant voltage supply, whereas the (usually much smaller) current I _ur is a constant Since it is drawn by a circuit directly connected to an external power supply that is not voltage regulated, it varies with the supply voltage V--thus, the current I _ur is shown to be a function of V in the expression below.
P _D = _Ir ^* V+ _Iur (V) ^* V

Similarly, heater power can be expressed in terms of heater current _IHC and voltage,
_PH1 = _IHC ^* V
where _IHC is generated according to the first aspect of the present invention to be inversely proportional to the power supply voltage V, for example, and can be described by the following expression.

In the above expression, ΔT is the temperature error signal, _TG is the temperature sensor gain of the error processing stage, and _IH /V is the power supply correction heater control signal generated according to Part I of this specification. and _CG is the current gain of the heater driver circuit.

According to a second aspect of the invention, a small amount of the heater control signal is subtracted before it is applied to the heater driver circuit.

This surplus current _Ic is absorbed in the total power capacity, so the constant current regulated current _Ir is increased by _Ic to _Ir1 :
I _r1 =I _r +I _C

装置内のヒータ以外で消費される電力Ｐ_Ｄ１の新規値は、以下のとおりである。

The new heater power _PH2 is expressed as:

The new value for the power P _D1 consumed by the non-heater in the device is:

The new total power P _Σ is thus the sum of P _H2 and P _D1 .

From the expression below, it can be seen that if _Ic is made equal to a certain value, the terms in brackets { } tend to be zero and the total power _PΣ is highly dependent on the supply voltage, as shown below. and does not rely on them to a greater degree than applying the Part I techniques alone. Therefore, the assembly responds to power supply voltage fluctuations more quickly than if the thermal control loop were able to compensate for such fluctuations. The optimum values of _IC required for this technique are:

For the best use of this technique, the current I _ur should be much smaller than I _r , which is usually the case for well-designed OCO devices. Also, in order to keep the total power consumption as low as possible, the current gain _CG of the heater drive circuit should be large, eg greater than 30.

The invention will be further described with reference to the accompanying drawings.

1 shows the temperature control loop of a conventional (according to the prior art) temperature stabilization device; 4 shows the heating power supply of the temperature stabilizer. Figure 3 shows a heating power supply for a temperature stabilization device incorporating the second aspect of the invention; 1 shows an example embodiment of a temperature stabilization device incorporating the first aspect of the invention; 4 illustrates an example implementation of a power supply detection circuit. Fig. 10 shows a graph of temperature control slope plotted as a function of adjustable circuit resistance; 4 illustrates an example circuit configuration for generating a power supply dependent heater control signal. 1 shows an embodiment of a temperature stabilization device incorporating both the first and second aspects of the invention; 4 shows how to perform a current subtraction function. 4 shows an example heater driver and heater circuit. 3 shows an example of a heater driver and a heater circuit to which a heater control signal subtraction circuit is added. Fig. 3 shows an embodiment of a current sink module; The performance benefits obtained by utilizing the techniques of the present invention are illustrated. The performance benefits obtained by utilizing the techniques of the present invention are illustrated. The performance benefits obtained by utilizing the techniques of the present invention are illustrated. The performance benefits obtained by utilizing the techniques of the present invention are illustrated.

FIG. 4 shows an embodiment of a temperature stabilization device incorporating the first aspect of the invention. The device assembly temperature is sensed using temperature sensor 1 and compared to the desired device assembly temperature (“setpoint”) to calculate a temperature error value that is input to error processing block 2 . This block generates heater control signals according to the selected control algorithm, as previously described herein. Whereas in a conventional temperature stabilization device the heater control signal is connected to the driver circuit of the heater(s), in the device of the present invention an additional circuit--the power supply correction circuit 3--is introduced to provide the heater control signal , and the heater control signal is dependent on the level of the power supply voltage as it is adjusted for changes in the level of the power supply voltage. The latter -V _SUPPLY - is therefore the second input required to the power supply correction block 3, as shown in FIG. As such, the resulting power supply corrected heater control signal at point 4 is a function of both the current value of the temperature error and the current value of the power supply voltage.

The power supply correction heater control signal at point 4 is connected as an input to the heater(s) driver circuit 5, which drives the heater(s) 6 to control the stable temperature of the device assembly 7. and maintain.

The heater control signal 4 is continuously adjusted with respect to any change in power supply level (where constant voltage adjustments are made at very short intervals, e.g. every 30 ms), such changes: The temperature stabilizer of the present invention responds much more quickly than in conventional temperature stabilizers.

One method of implementing the power supply correction circuit is to implement the power supply correction circuit as a multiplier circuit that produces a product of the signal at the output of the error processing block and a signal that decreases linearly with the power supply voltage. make sure to In other words, in one embodiment, the output of the power detection circuit is multiplied by the heat demand signal and the resulting signal is used to drive the heating device.

One embodiment of the power detection circuit is shown in FIG. The circuit consists of bipolar transistors Qref, Q0 and Q1, NMOS transistors M0 and M1 with size ratio M, a current source Iref and emitter resistors R0 and _R1 through which currents _l0 and l1 flow. V _REG , V _UREG , and V _REF are the regulated, unregulated, and reference voltages used by the circuit, while IOUT is the voltage generated by the circuit. is a power supply detection signal. Qref, Q0 and Q1 are configured so that the same voltage as the reference voltage appears at the emitters of Q0 and Q1, making the voltage at these points approximately constant. As the non-regulated supply voltage changes, the current I0 also changes. Current I0 increases when the non-regulated power supply voltage increases, and current I0 decreases when the non-regulated power supply voltage decreases. A current mirror (including M0 and M1) with a current gain of M subtracts M times I0 from the current I1. This difference is the output current signal (IOUT) representing the power supply voltage dependent signal.

Heating power can be expressed as:
Power=V _vureg ×I _out

In this circuit,
V _reg =V _ref ×2
I _out =I ₁ -M×I ₀

Here, the heating power can be expressed as follows.

がなり立つ場合に実現される。
したがって、

となる。 The minimum sensitivity of heating power to supply voltage fluctuations is given by:

is realized when
therefore,

becomes.

The optimum value of M given the values of R0 and R1 is:

For this reason, by changing the value of the resistor _R0 , the heater power supply sensitivity can be minimized when the power supply voltage is given arbitrarily, as shown in FIG. /V) is plotted as a function of resistance, with the optimum resistance near the plot across the horizontal axis (ie, where the sensitivity to power supply variations is near zero). Alternatively, the value of M can be changed to obtain the optimum source sensitivity given the values of R0 and R1. In embodiments of the present invention, the value of M and the value of R0/R1 ratio can be selected simultaneously.

An embodiment incorporating all circuitry for generating power dependent heater control signals is shown in FIG. This circuit is an addition that produces the product of the power sense circuit shown in FIG. 5 and the power sense signal IOUT generated by the previously described temperature error processing circuit and the HEATER DEMAND signal (used together with the HEATER REFERENCE signal). and a circuit. Additional circuitry consists of NPN transistors Q2, Q3, Q10-Q17, resistors R6 and R7, and current sources I3 and I4. In this circuit, HEATER REFERENCE and HEATER DEMAND are fed into differential pair Q2, Q3, the current is set by current sources I3, I4, and the operating state is set by R7, Q17 and Q18. A differential signal is then provided from Q2 and Q3 to Q11 and Q10, which divide the current IOUT from the power detection circuit according to the differential signal. Q12 and Q13 function as a current mirror, and the difference between the currents of Q10 and Q11 is supplied to the subsequent current mirrors Q14 and Q15 to generate the final output current, thereby generating power supply correction heater signals and heater control signals. to control the power consumed by the device's heater.

FIG. 8 shows an embodiment of a temperature stabilization device incorporating both the first and second aspects of the invention. Compared to and in addition to the device structure shown in FIG. 4, an additional circuit 8 "heater control signal subtraction" is introduced to subtract a small portion of the power supply corrected heater control signal. As previously described herein, this is presented to the heater control loop as if the heater control loop were also controlling internal power consumption, thereby providing the first Aspect power supply correction techniques can provide instantaneous or near-instantaneous correction of internal power consumption for power supply changes.

One way to implement the current subtraction function is to add a simple programmable current source that draws a settable amount of current from the power compensation heater, as shown in FIG.

An example of mounting a heater driver and heater circuit is shown in FIG. 10, where the heater control current Iheat is multiplied by 68 with a current mirror formed by two NMOS transistors with a size ratio of 68 to 1 and a larger transistor. is used as the heater for the device assembly.

An example of adding a heater control signal (current) subtraction circuit to the circuit shown in FIG. 10 is shown in FIG. terminal Iselect carries a binary signal to select and subtract the correct amount of heater control signal (current), the current after subtraction being sent to the circuit's reference ground through the Ia terminal. flow into.

An example embodiment of a Current Sink Module is shown in FIG. In this circuit, the reference current Iref is mirrored from transistor N1 to transistors N2, N3 and N4 at a rate of 1, 2 and 4 times. Switches S1, S2, and S3 are controlled by signals on the Iselect bus to source a binary weighted value reference current 0-7 times through terminal Ia.

Figures 13-16 illustrate the performance benefits obtained by utilizing the techniques of the present invention. 13 and 14 show the measured transient response of a conventional OCXO to power supply voltage changes. FIG. 13 shows the transient output frequency change following a 5% supply voltage rise, the frequency destabilizing as a result of the supply voltage change and the transient disturbances settling as shown in FIG. takes more than 30 seconds, and a peak-to-peak frequency shift of 12 ppb occurs during the transient response. A 5% drop in the power supply voltage causes a transient output frequency change of similar magnitude and duration, as shown in FIG.

An OCXO device that includes one embodiment of the present invention exhibits significantly accelerated response to step changes in power supply voltage. As shown in FIG. 15, the transient output frequency response to an increase in supply voltage in the OCXO of the present invention occurs over less than one second without any significant frequency shift compared to that of the conventional OCXO. The OCXO device of the present invention exhibits similarly short transient response with no significant frequency shift for a 5% supply voltage drop, as shown in FIG.

Claims (14)

A temperature stabilization device that can be powered by a mains voltage source, said device comprising a heater circuit for heating an assembly of said device and a heater control signal for generating a heater control signal to control the amount of power consumed in said heater circuit. and a circuit configured to control the heater control signal, wherein the heater control signal is generated as a multiplied product of a heating request signal and a power supply voltage detection signal. 2. The temperature stabilization device of claim 1, wherein additional electronic circuitry is configured to reduce the absolute value of the heater control signal before the heater control signal is applied to the heater circuit or heater driver circuit. . A temperature stabilization device according to any of claims 1 or 2, wherein the temperature stabilization device is an Oven-Controlled Oscillator device. 4. The oven-controlled oscillator device of claim 3, wherein the oven-controlled oscillator device is an Oven-Controlled Crystal Oscillator device. 4. The oven-controlled oscillator device according to claim 3, wherein the oven-controlled oscillator device is an oven-controlled SAW oscillator device. 4. The oven-controlled oscillator device of claim 3, wherein the oven-controlled oscillator device is an Oven-Controlled MEMS Oscillator device. The circuit configured to generate a heater control signal to control the amount of power consumed in the heater circuit controls the assembly temperature of the device up to ±5% of a desired operating ambient temperature range of the device. A temperature stabilizing device according to any one of the preceding claims, configured to maintain within. The circuit configured to generate a heater control signal to control the amount of power consumed in the heater circuit adjusts the assembly temperature of the device up to ±1% of the desired operating ambient temperature range of the device. A temperature stabilizing device according to any one of the preceding claims, configured to maintain within. The circuit, configured to generate a heater control signal to control the amount of power consumed in the heater circuit, adjusts the assembly temperature of the device to within a desired operating ambient temperature range of the device up to ±0. A temperature stabilization device according to any preceding claim, configured to maintain within 01%. 10. The temperature stabilization device of any of claims 1-9, wherein the heater control signal is configured to be electronically adjusted such that variations in the power supply voltage level do not exceed ±10%. 10. A temperature stabilization device as claimed in any preceding claim, wherein the heater control signal is configured to be electronically adjusted such that variations in the power supply voltage level do not exceed ±5%. A temperature stabilizer as claimed in any one of claims 1 to 9, wherein the heater control signal is configured to be electronically adjusted such that the power supply voltage level does not vary by more than ±1%. An oven controlled oscillator device that can be powered by a mains voltage source, said device comprising: an oscillator circuit; a heater circuit for heating an assembly of said device; and wherein the heater control signal is generated as a product of a heat request signal multiplied by a power supply voltage sense signal. 14. The oven controlled oscillator of claim 13, wherein additional circuitry is configured to reduce the absolute value of the heater control signal before the heater control signal is applied to the heater circuit or to the heater driver circuit. Device.

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