Temperature detector systems and methods

Claims

We claim:

1. A temperature detector, comprising:

(a) temperature sensing circuitry having an output that varies with a temperature to create a temperature variation;

(b) calibration circuitry electrically coupled to receive said output that varies with said temperature to cream said temperature variation, said calibration circuitry interprets said temperature variation, outputs a value that represents said temperature;

(c) said temperature sensing circuitry including a temperature-to-time first converter, said temperature-to-time first converter outputting a time interval with length depending upon an input temperature;

(d) said calibration circuitry including a time-to-number second converter, said time-to-number second converter with input coupled to said temperature-to-time first converter to receive said time interval, said time-to-number second converter outputs a number version of said input temperature;

(e) said time-to-number second converter including a second oscillator coupled to a time-to-number second counter, with said time-m-number second counter in response to said second oscillator input producing digital number during said time interval; and

(f) said temperature-to-time first converter including a first oscillator with a temperature dependent period coupled to a counter for providing a temperature dependent time interval, said time interval for said counter determined by the number of oscillations counted for a predetermined count.

2. The temperature detector of claim 1, wherein said time-to-number second converter includes a second oscillator coupled to a time-to-number second counter, with said time-to-number second counter counting said number of oscillations produced by said second oscillator for said time interval.

3. The temperature detector of claim 2, further comprising:

(a) power supply regulator circuitry electrically coupled to said temperature sensing circuitry to coordinate power to said temperature sensing circuitry.

4. The temperature detector of claim 3, wherein:

(a) said time-to-number second converter comprises a prescaler between said second oscillator and said time-to-number second counter, said prescaler blocking a fraction of said number of oscillations from said second oscillator from driving said time-to-number second counter.

5. The temperature detector of claim 3, further comprising:

(a) an output temperature register; and

(b) a repetition controller coupled to said temperature-to-time first converter and said time-to-number second converter and said output temperature register;

(c) wherein during said time interval said repetition controller first

(i) loads a base count into said time-to-number second counter and a base temperature into said output temperature register, next

(ii) when said time-to-number second counter has counted down said base count, said repetition controller loads a slope count into said time-to-number second counter, then

(iii) when said time-to-number second counter has counted down said slope count, said repetition controller increments said base temperature in said output temperature register and loads a second slope count into said time-to-number second counter, and

(iv) said repetition controller repeats incrementing said base temperature stored in said output temperature register and loading said slope count into said time-to-number second counter and loading said second slope count into said time-to-number second counter until said time interval expires.

6. The temperature detector of claim 5, wherein:

(a) said time-to-number second converter comprises a slope incrementer coupled to said time-to-number second counter and to said repetition controller.

7. The temperature detector of claim 2, further wherein said time-to-number second converter has at least one output terminal, said at least one output terminal coupled to an electrical device selected from the group consisting of microcontrollers and microprocessors, and/or any combination thereof.

8. The temperature detector of claim 2, wherein said number version outputted by said time-to-number second converter is a binary representation of said temperature detector in standard units of measurement of said temperature.

9. The temperature detector of claim 3, wherein said second oscillator of said time-to-number second converter is not variable.

10. The temperature detector of claim 2, wherein said time-to-number second converter approximates said number version of said input temperature by fitting a preselected mathematical model to said time interval.

11. The temperature detector of claim 10, wherein said preselected mathematical model is quadratic fit.

12. The temperature detector of claim 10, where said preselected mathematical model comprises an iterative, linear model and then a quadratic model.

13. The temperature detector of claim 3, wherein said second oscillator has a temperature dependent period and said time-to-number second converter comprises prescaler circuitry to transform said temperature dependent period into a temperature independent period.

14. The temperature detector of claim 13, wherein said prescaler circuitry transforms said temperature dependent period into said temperature independent period by scaling said time interval by a preselected factor.

15. The temperature detector of claim 14, wherein said preselected factor correspond to a change in said temperature from a preselected maximum temperature.

16. The temperature detector of claim 8, wherein said standard units of measurement of said temperature are selected from the group consisting of Celsius and Fahrenheit degrees.

17. The temperature detector of claim 2 further comprising:

control circuitry coupled to said temperature-to-time first converter and to said time-to-number second converter to activate said temperature-to-time first converter and said time-to-number second converter and to synchronize communication between said temperature-to-time first converter and to said time-to-number second converter.

18. The temperature detector of claim 2, wherein said time-to-number second converter is continuously running.

19. The temperature detector of claim 1, wherein said power supply regulator circuitry regulates said power supplied by a power supply so that said power from a primary power source does not vary.

20. The temperature detector of claim 19, wherein said primary power source supplies said power that is approximately equal or greater than 3 volts.

21. The temperature detector of claim 1, comprises

(c1) an input to receive a reference voltage;

(c2) at least one output coupled to said temperature sensing circuitry; and

(c3) first circuitry coupled to said input to provide power supply insensitive voltage output coupled to said output, said power supply insensitive voltage output is consistent with said reference voltage.

22. The temperature detector of claim 21, wherein said first circuitry comprising

a first transistor having a first source, a first drain, and a first gate, said first source coupled to a reference voltage generator;

a second transistor having a second source, a second drain, and a second gate;

a third transistor having a third source, a third drain, and a third gate;

a charge pump having an output coupled to said first drain and said first gate of said first transistor;

said first gate of said first transistor coupled to said second gate of said second transistor and said third gate of said third transistor; and

said second source of said second transistor and said third source of said third transistor coupled to power the first and second oscillators respectively.

23. The temperature detector of claim 1, wherein said value has a resolution and further comprising resolution enhancement circuitry coupled to said calibration circuitry that enhances said resolution of said value.

24. The temperature detector of claim 23, further comprising software means executed by said resolution enhancement circuitry.

25. A temperature detector, comprising:

(a) temperature sensing circuitry having an output that varies with a temperature to create a temperature variation, said temperature sensing circuitry including a temperature-to-time first converter, said temperature-to-time first converter outputting a time interval with length depending upon an input temperature;

(b) calibration circuitry coupled to receive said output that varies with said temperature to create said temperature variation, said calibration circuitry interprets said temperature variation, outputs a value that represents said temperature, said value having a resolution, said calibration circuitry including a time-to-number second converter, said time-to-number second converter with input coupled to said temperature-to-time first converter to receive said time interval, said time-to-number second converter outputs a number version of said input temperature;

(c) said time-to-number second converter including a second oscillator coupled to a time-to-number see, end counter, with said time-to-number second counter in response to said second oscillator input producing a digital number during said time interval;

(d) said temperature-to-time first converter including a first oscillator with a temperature dependent period coupled to a counter for providing a temperature dependent time interval, said time interval for said counter determined by the number of oscillations counted for a predetermined count; and

(e) resolution enhancement circuitry coupled to said calibration circuitry that enhances said resolution of said value.

26. The temperature detector of claim 25, further comprising software means executed by said resolution enhancement circuitry.

27. A temperature detector, comprising:

(a) temperature sensing circuitry having an output that varies with a temperature to create a temperature variation;

(b) calibration circuitry electrically coupled to receive said output that varies with said temperature to create said temperature variation, said calibration circuitry interprets said temperature variation, outputs a value that represents said temperature;

(c) power supply regulator circuitry electrically coupled to said temperature sensing circuitry to coordinate power to said temperature sensing circuitry;

(d) said temperature sensing circuitry comprises a temperature-to-time first converter, said temperature-to-time first converter outputting a time interval with length depending upon an input temperature;

(e) said temperature-to-time first converter including a first oscillator with a temperature dependent period coupled to a counter, said time interval for said counter to count a number of oscillations of said first oscillator; and

(f) said calibration circuitry including a time-to-number second converter, said time-to-number second converter with input coupled to said temperature-to-time first converter to receive said time interval, said time-to-number second converter outputs a number version of said input temperature;

(g) said time-to-number second converter including a second oscillator coupled to a time-to-number second counter, with said time-to-number second counter counting said number of oscillations produced by said second oscillator for said time interval.

28. The temperature detector of claim 27, wherein:

(a) said time-to-number second converter includes a prescaler between said second oscillator and said time-to-number second counter, said prescaler blocking a fraction of said number of oscillations from said second oscillator from driving said time-to-number second counter.

29. The temperature detector of claim 27, further comprising:

(a) an output temperature register; and

(b) a repetition controller coupled to said temperature-to-time first converter and said time-to-number second converter and said output temperature register;

(c) wherein during said time interval said repetition controller first

(i) loads a base count into said time-to-number second counter and a base temperature into said output temperature register, next

(ii) when said time-to-number second counter has counted down said base count, said repetition controller loads a slope count into said time-to-number second counter, then

(iii) when said time-to-number second counter has counted down said slope count, said repetition controller increments said base temperature in said output temperature register and loads a second slope count into said time-to-number second counter, and

(iv) said repetition controller repeats incrementing said base temperature stored in said output temperature register and loading said slope count into said time-to-number second counter and loading said second slope count into said time-to-number second counter until said time interval expires.

30. The temperature detector of claim 29, wherein:

(a) said time-to-number second converter comprises a slope incrementer coupled to said time-to-number second counter and to said repetition controller.

31. The temperature detector of claim 27, wherein said second oscillator of said time-to-number second converter is not variable.

32. The temperature detector of claim 27, wherein said second oscillator has a temperature dependent period and said time-to-number second converter comprises prescaler circuitry to transform said temperature dependent period into a temperature independent period.

33. The temperature detector of claim 32, wherein said prescaler circuitry transforms said temperature dependent period into said temperature independent period by scaling said time interval by a preselected factor.

34. The temperature detector of claim 33, wherein said preselected factor corresponds to a change in said temperature from a preselected maximum temperature.

35. The temperature detector of claim 27, wherein said temperature-to-time first converter and said time-to-number second converter are combined into an integrated circuit.

36. The temperature detector of claim 27, wherein said temperature sensing circuitry, said calibration circuitry, and said power supply regulator circuitry are combined into a single integrated circuit.

37. The temperature detector of claim 27, further wherein said time-to-number second converter has at least one output terminal, said at least one output terminal coupled to an electrical device selected from the group consisting of microcontrollers and microprocessors, and/or any combination thereof.

38. The temperature detector of claim 27, wherein said number version outputted by said time-to-number second converter is a binary representation of said temperature detector in standard units of measurement of said temperature.

39. The temperature detector of claim 38, wherein said standard units of measurement of said temperature are selected from the group consisting of Celsius and Fahrenheit degrees.

40. The temperature detector of claim 27 further comprising:

control circuitry coupled to said temperature-to-time first converter and to said time-to-number second converter to activate said temperature-to-time first converter and said time-to-number second converter and to synchronize communication between said temperature-to-time first converter and to said time-to-number second converter.

41. The temperature detector of claim 27, wherein said time-to-number second converter is continuously running.

42. The temperature detector of claim 27, wherein said power supply regulator circuitry regulates said power supplied by a power supply so that said power form a primary power source does not vary.

43. The temperature detector of claim 42, wherein said primary power source supplies said power that is approximately equal or greater than 3 volts.

44. The temperature detector of claim 27, further comprising:

an input to receive a reference voltage;

at least one output coupled to said temperature sensing circuitry; and

first circuitry coupled to said input to provide power supply insensitive voltage output coupled to said output, said power supply insensitive voltage output is consistent with said reference voltage.

45. The temperature detector of claim 27, wherein said value has a resolution and further comprising resolution enhancement circuity coupled to said calibration circuitry that enhances said resolution of said value.

46. The temperature detector of claim 45, further comprising:

software means executed by said resolution enhancement circuitry.

47. The temperature detector of claim 27, wherein said time-to-number second converter approximates said number version of said input temperature by fitting a preselected mathematical model to said time interval.

48. A temperature detector, comprising:

(a) temperature sensing circuitry having an output that varies with a temperature to create a temperature variation;

(b) calibration circuitry electrically coupled to receive said output that varies with said temperature to create said temperature variation, said calibration circuitry interprets said temperature variation, outputs a value that represents said temperature;

(c) power supply regulator circuitry electrically coupled to said temperature sensing circuitry to coordinate power to said temperature sensing circuitry;

(d) said temperature sensing circuitry including a temperature-to-time first converter, said temperature-to-time first converter outputting a time interval with length depending upon an input temperature;

(e) said calibration circuitry including a time-to-number second converter, said time-to-number second converter with input coupled to said temperature-to-time first converter to receive said time interval, said time-to-number second converter outputs a number version of said input temperature;

(f) said time-to-number second converter approximates said number version of said input temperature by fitting a preselected mathematical model to said time interval; and

(g) said preselected mathematical model is quadratic fit.

49. A temperature detector, comprising:

(a) temperature sensing circuitry having an output that varies with a temperature to create a temperature variation;

(b) calibration circuitry electrically coupled to receive said output that varies with said temperature to create said temperature variation, said calibration circuitry interprets said temperature variation, outputs a value that represents said temperature;

(c) power supply regulator circuitry electrically coupled to said temperature sensing circuitry to coordinate power to said temperature sensing circuitry;

(d) said temperature sensing circuitry including a temperature-to-time first converter, said temperature-to-time first converter outputting a time interval with length depending upon an input temperature;

(e) said calibration circuitry including a time-to-number second converter, said time-to-number second converter with input coupled to said temperature-to-time first converter to receive said time interval, said time-to-number second converter outputs a number version of said input temperature;

(f) said time-to-number second converter approximates said number version of said input temperature by fitting a preselected mathematical model to said time interval; and

(g) said preselected mathematical model comprises an iterative, liner model and then a quadratic model.

50. A temperature detector, comprising:

(a) temperature sensing circuitry having an output that varies with a temperature to create a temperature variation;

(b) calibration circuitry electrically coupled to receive said output that varies with said temperature to create said temperature variation, said calibration circuitry interprets said temperature variation, outputs a value that represents said temperature;

(c) power supply regulator circuitry electrically coupled to said temperature sensing circuitry to coordinate power to said temperature sensing circuitry;

(d) an input to receive a reference voltage;

(e) at least one output coupled to said temperature sensing circuitry;

(f) first circuitry coupled to said input to provide power supply insensitive voltage output coupled to said output, said power supply insensitive voltage output is consistent with said reference voltage; and

(g) said first circuitry including

(i) a first transistor having a first source, a first drain, and a first gate, said first source coupled to a reference voltage generator;

(ii) a second transistor having a second source, a second drain, and a second gate;

(iii) a third transistor having a third source, a third drain, and a third gate;

(iv) a charge pump having an output coupled to said first drain and said first gate of said first transistor;

(v) said first gate of said first transistor coupled to said second gate of said second transistor and said third gate of said third transistor; and

(vi) said second source of said second transistor and said third source of said third transistor coupled to power the first and second oscillators respectively.

(C) Copyright, Dallas Semiconductor Corporation 1994. All of the material in this patent application is subject to copyright protection under the copyright laws of the United States and of other countries. As of the first effective filing date of the present application, this material is protected as unpublished material.

Portions of the material in the specification and drawings of this patent application are also subject to protection under the maskwork registration laws of the United States and of other countries.

However, permission to copy this material is hereby granted to the extent that the owner of the copyright and maskwork rights has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure, as it appears in the United States Patent and Trademark Office patent file or records, but otherwise reserves all copyright and maskwork rights whatsoever.

FIELD OF THE INVENTION

The present invention relates to electronic devices, and, more particularly, to integrated circuit temperature detection systems and methods.

BACKGROUND

Accurate and timely temperature information is needed in a host of applications in modern industrial society. For instance, temperature monitoring is required in controlling processes, maintaining controlled environments (e.g., temp-cycle test equipment, air conditioning), monitoring equipment, and monitoring exposure. Moreover, automatic (electronic) systems (e.g., process control systems) typically require all electronic temperature measurement systems and the data provided by electronic temperature measurement system to be in a digital format, so that microcontrollers and microprocessors often used in those applications can readily accept and process the temperature information.

Existing temperature measurement devices often combine circuitry with discrete temperature sensitive items (e.g., thermistors), which are inherently analog devices and provide an analog output. An analog-to-digital converter is then needed to convert the analog output to a digital format. Alternative existing temperature measurement devices do not provide an accurate, reliable reading (if any) over a large temperature range. All of these characteristics associated with existing temperature measurement devices may adversely affect the overall efficiency and accuracy of the system as well as the degree and ease with which the resulting system can be combined into a small, miniaturized circuit (e.g., integrated).

Problems encountered with addressing these shortcomings are numerous. In particular, modern temperature measurement devices do not address or accommodate for the sensitivities of many electrical/electronic components and subcomponents (e.g., oscillators, power supplies, etc.) to temperature and/or changes in temperature. In addition, modern temperature measurement devices do not provide high degrees of resolution and/or adjustable degrees of resolution. Similarly, modern temperature measurement devices that produce a digital output do not provide temperatures having increased accuracy, resolution, etc. over a wide range of temperatures.

SUMMARY OF THE INVENTIONS

Preferred system embodiments of the disclosed temperature detector generally comprise temperature sensing circuitry, calibration circuitry, and power supply regulator circuitry. The temperature sensing circuitry has an output that varies with temperature. The calibration circuitry receives the output that varies with temperature, interprets the temperature variation, and outputs a value that represents the temperature. The power supply regulator coordinates power input to the temperature sensing circuitry and to the calibration circuitry. The temperature sensing circuitry, calibration circuitry, and power supply regulator are preferably combined into an integrated circuit. Note that while numerous modifications exist, the resolution can be increased by reading the actual values contained in the registers and/or not rounding the values contained therein. In addition, note that the modifications to enhance resolution are independent of the power regulation circuitry, so that the power regulation circuitry is not necessarily needed for some applications.

More specifically, while numerous temperature sensing circuitry can be used, the temperature sensing circuitry in preferred embodiments comprises delay circuitry to produce a signal delayed by a length of time correlating with the temperature and timing circuitry coupled to receive the signal and to convert the signal into the output correlating to the temperature output. The temperature output is in a digital format. In addition, the temperature sensing circuitry further comprises control circuitry coupled to the timing circuitry and to the delay circuitry to activate the delay circuitry and the timing circuitry and synchronize all communication between the timing circuitry and the delay circuitry. Preferably, the timing circuitry continuously runs and has a reset to turn on and off the timing circuitry. The timing circuitry is intermittently active to limit power consumption. The timing circuitry and the delay circuitry may be powered by a battery. The temperature output varies approximately linearly upon temperature. The digital output varies approximately linearly upon temperature.

Moreover, the delay circuitry comprises a first oscillator to generate oscillations at a first oscillation rate. The first oscillation rate preferably has a first sensitivity to temperature (e.g., sensitive to changes in temperature) and a first counter coupled to the first oscillator and to count the oscillations generated by the first oscillator. The timing circuitry comprises a second oscillator to generate oscillations at a second oscillation rate. The second oscillation rate preferably has a second sensitivity to temperature (e.g., insensitive to changes in temperature). A second counter coupled to the first counter of the delay line circuitry to count the oscillations generated by the second oscillator. The second counter preferably wraps around, so that said second counter counts continuously.

Regarding the sensitivities to temperature, the first oscillator may comprise RC oscillator circuitry having at least one set of a first resistor and a first capacitor coupled together and the second oscillator comprises RC oscillator circuitry having at least one set of a second resistor and a second capacitor coupled together, where the first resistor(s) has a first sensitivity to temperature and the second resistor(s) has a second sensitivity to temperature. As stated above, the first sensitivity is different from the second sensitivity. Both the first resistor(s) and the second resistor(s) are selected from the group consisting of standard polysilicon resistors and n-well diffused resistors. The first oscillator and said second oscillator oscillate at approximately 200 KHz. The temperature ranges between a first temperature (e.g., -55 degrees Celsius) and a second temperature (e.g., +125 degrees Celsius). As stated above, the first sensitivity in alternate preferred embodiments is greater than the second sensitivity, so that the first oscillation rate is more sensitive to temperature than the second oscillation rate. The second sensitivity is very low and the first sensitivity is comparatively quite high, so that the first oscillation rate is not very sensitive to temperature and the second sensitivity is not very sensitive to temperature.

The calibration circuitry interprets the temperature variation by fitting a preselected mathematical model to the time interval, which in some preferred embodiments is a quadratic fit. The "fitting" comprises an iterative, linear fit and then a quadratic fit. In other words, temperature sensing circuitry provides an integrated circuit temperature detector which runs an oscillator with a large temperature dependency up to a fixed count to thereby generate a time interval indicating temperature. The time interval may be used to gate an oscillator with a small temperature dependence to generate an output count (number of oscillations) varying approximately linearly with temperature. This provides for simple calibration due to the linearity and yields a direct digital expression of temperature. Alternative temperature detectors could use other temperature sensitive time interval generators such as an integrator of a temperature sensitive current. Digital temperature measurement permits use of the measurement as a direct input to a microcontroller or, more simply, as an address for a Read Only Memory ("ROM") to read out desired process control parameters.

The power regulator preferably regulates the power supply over a wide range of global power supply voltages in order to insure a fixed power supply. In addition, the power regulator enables the power supply to provide a fairly large amount of current (e.g., >1 mA). The charge pump permits the power supply to remain regulated, even when power supplied to it is extremely low. However, when V.sub.DD goes to about 3 volts, regulation is killed, so the lower limit of V.sub.DD is limited to around 3.5 volts. Preferred circuit embodiments of the power regulator comprise a charge pump input having an output coupled to the drain and gate of a first transistor. The source of the first transistor is coupled to the output of a reference voltage generator to provide V.sub.REF. The gate of the first transistor is preferably coupled to the gates of a second transistor and a third transistor. The sources of the second transistor and the third transistor are coupled to power the first and second oscillators respectively.

The advantages are as follows. Preferred system and process embodiments measure temperature using monolithic silicon implementations without an external sensor. In contrast to other temperature measuring circuits, which typically attempt to measure a change in V.sub.be for a bipolar transistor, this sensor compares periods of two oscillators having different temperature coefficients (hereafter "tempcos"). Preferred system embodiments are approximately accurate within .+-.0.5.degree. Celsius (hereafter "C.") in the range from -55.degree. C. to 125.degree. C. Disclosed circuitry operates with supply voltages of 3.5 V to 5.5 V and consumes no more than 55 .mu.A when operating and leakage only when in a standby condition.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages will become apparent from the following and more particular description of the various embodiments of the invention, as illustrated in the accompanying drawings, wherein:

FIG. 1A is a functional/structural block circuit diagram of a preferred embodiment of temperature detector 200;

FIG. 1B is a functional/structural block circuit diagram showing the improved power supply regulator combined with the functional/structural block circuit diagram of the preferred embodiment temperature detector 200 shown in FIG. 1A;

FIG. 1C is a functional/structural block circuit diagram of an alternate preferred embodiment temperature detector 200 shown in FIG. 1A comprising a look-up table to do the time-to-output conversion;

FIG. 2A is a more detailed block diagram of the temperature detector 200, shown in FIG. 1A;

FIG. 2B is an alternate, even more-detailed preferred block diagram than that shown in FIG. 2A of the temperature detector 200;

FIG. 2C is a more detailed preferred block diagram of the temperature detector 200, shown in FIG. 1B showing the improved power supply regulator 211 combined with the functional/structural block circuit diagram of the preferred embodiment temperature detector 200 shown in FIG. 1A;

FIG. 2D is a more detailed preferred block diagram of preferred embodiment of temperature detector 200 in FIG. 1A that is generally denoted by reference numeral 600;

FIG. 2E-2F illustrate iteration in the second preferred embodiment;

FIG. 3A is an illustration of an oscillator used in the temperature detector 200 of FIGS. 2A and 2B;

FIG. 3B is an illustration of an alternate embodiment of the oscillator used in FIGS. 2A and 2B;

FIG. 3C is an illustration of an alternate embodiment of the oscillator used in FIGS. 2A and 2B;

FIG. 4 is a flow chart illustrating operation of the temperature detector 200 of FIG. 5;

FIG. 5 is a graph showing the low TC period variance of "0" TC oscillator 310 (in FIG. 2A) or 210 (in FIG. 2B);

FIG. 6 is a graph showing that when an RC time constant is being used to generate the timing for an oscillator (shown in FIG. 3B), the capacity charges to a trip voltage (ref);

FIG. 7 is a graph illustrating the resistor nonlinear variance with temperature;

FIG. 8 is a graph showing the resulting quadratic over the time of the delay;

FIG. 9 is a graph illustrating the curvature in the temperature characteristic of the ((High ("hi") Temperature Coefficient ("TC") Oscillator ("OSC")) hi TC Oscillator 310 (e.g., or temperature-independent oscillator 310 (in FIG. 2A) or temperature insensitive oscillator 310) (in FIG. 3A) and TC Oscillator 320 (e.g., or temperature-dependent oscillator 320 (in FIG. 3A) or temperature sensitive oscillator 320) (in FIG. 3B);

FIG. 10 is a block diagram of the second order curve fit described in the text for preferred temperature detector 200;

FIG. 11 is a graph showing the piecewise linear fit of count curve of the preferred temperature detector 200;

FIG. 12 is a graph showing the actual count (solid line), fitted count (dotted line) and quantized fitted count (dashed line) (which are practically on top of one another) vs. temperature;

FIG. 13 is a graph showing the Error in Degrees C. of actual count from fitted count vs. temperature;

FIG. 14 is a graph showing the adjustments for ((Low ("lo") Temperature Coefficient ("TC") Oscillator ("OSC")) lo TC Oscillator Adjustment vs. temperature;

FIG. 15 is a graph showing the actual and fit values for the period for hi TC oscillator 320;

FIG. 16 is a graph showing the actual data (solid line), second order fit (dotted line), and linear fit (dashed line) of the lo TC Oscillator 310;

FIG. 17 is a graph of the actual count and count fit based on a constant period of lo TC oscillator 310;

FIG. 18 is a graph showing the oscillator adjustment error;

FIGS. 19A-19C are graphs of temperature sensor error vs. iteration for each iteration compared to second order fit of count approach;

FIG. 19D is a graph of temperature conversion times vs. temperature vs. number of iterations;

FIG. 20 is a functional/structural block diagram of a preferred embodiment temperature detector 200 that provides higher resolution;

FIG. 21 is a more detailed circuit implementation of the functional/structural block diagram of slope accumulator 631, which comprises tempco register 660 (e.g., or intercept and slope register 660) and accumulator 662 in FIG. 2D, and compare block 671 in FIG. 20, which is used to provide higher resolution;

FIG. 22 is a preferred circuit diagram of compare block 671;

FIG. 23 is a preferred circuit diagram of temp.sub.-- dcomp block 679 of FIG. 22, showing preferred circuitry;

FIG. 24 is a preferred circuit diagram of power supply regulator 211 along with temperature-dependent oscillator 320 and temperature-independent oscillator 310 shown in FIG. 1B and 2C;

FIG. 25 is a the preferred circuitry of power supply regulator 211 along with temperature-dependent oscillator 320 ((High ("hi") Temperature Coefficient ("TC") Oscillator ("OSC") 320 in FIG. 2A) and temperature-independent oscillator 310 ((Low ("lo") Temperature Coefficient ("TC") Oscillator ("OSC")) shown in FIGS. 1B, 2C, and 24;

FIG. 26 is the schematic of preferred circuitry for "regpump" block 221 of FIG. 25, which is used to regulate the charge pump;

FIG. 27 is the schematic of preferred circuitry for "pumposc" block 223 of FIG. 26, which is used to regulate the charge pump;

FIG. 28 is the schematic of preferred circuitry for "smallpump" block 227 of FIG. 26, which is used to regulate the charge pump; and

FIG. 29 is a schematic showing the prescaler circuitry 680 in FIG. 2D.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1A is a functional/structural block circuit diagram of one preferred embodiment of the temperature detector or temperature sensing circuitry, generally denoted by reference numeral 200, which comprises time-to-output converter 210 (e.g., or timing circuit 210), temperature-to-time converter 220 (e.g., or delay circuitry 220), and control block 230, which controls the operation of temperature-to-time convertor 220 and time-to-output converter 210 and also houses circuitry to calibrate the outputs of these modules that reflect temperature. Time-to-output converter 210 has a much smaller temperature dependence than temperature-to-time converter 220. Basically, temperature-to-time converter 220 provides a time interval dependent upon temperature, and this time interval controls (such as the interval from turning on until turning off) time-to-output converter 210. That is, temperature detector 200 provides a temperature-to-time converter 220. Timing circuit 210 produces an output indicative of the duration of its activity which thus correlates With temperature and may have any desired format.

For example, timing circuit 210 could provide a digital output and thus would essentially be a time-to-count converter. Various implementations of blocks 210 and 220 appear in the following embodiments and include both the use of a continuously running timing circuit 210 with a reset as the "turning on and turning off" and the use of an only-intermittently active timing circuit 210 to limit power consum