JP2005092793A - Electronic appliance circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an electronic appliance circuit where LSI design is easy even in a fast circuit and which is small and operates stably by reducing variation of signal propagation delay time inside of LSI with respect to temperature variation. <P>SOLUTION: The temperature of an LSI package case is detected by a thermister Rth1 of a temperature negative characteristic and thermister Rth2 of a temperature positive characteristic, and intermediate voltage Vk obtained by dividing LSI driving voltage is compared with reference voltage by an error amplifier 2. The intermediate voltage is varied by the variation of the resistance value of a thermister with the temperature of the package case of the LSI. The variation of the intermediate voltage is compared with the voltage of a reference signal source by an error amplifier to control LSI driving voltage. By controlling the LSI driving voltage to be high when the temperature of the package case is high and to be low when the temperature of the package case is low, variation of the signal propagation delay time inside of the LSI with respect to temperature (delay coefficient) is reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic device circuit in which fluctuations in signal propagation delay time of a semiconductor circuit in an LSI due to temperature fluctuations are suppressed.

  The signal propagation delay time of an internal semiconductor circuit of an LSI (Large Scale Integrated circuit) depends on the semiconductor chip temperature (junction temperature) and the LSI drive voltage. In particular, in an environment without thermal convection such as in space, the junction temperature and the LSI package case temperature are in a proportional relationship. That is, as shown in FIG. 8, the signal propagation delay time increases as the LSI package case temperature increases, and the signal propagation delay time decreases as the LSI package case temperature decreases. As shown in FIG. 9, the signal propagation delay time decreases as the LSI drive voltage increases, and the signal propagation delay time increases as the LSI drive voltage decreases.

  In LSI design, the signal propagation delay time is taken into consideration so that each temperature and voltage can operate normally even under worst conditions. However, in applications where temperature control is difficult due to large temperature fluctuations in space, etc., and air cooling fans cannot be used because there is no thermal convection, and design of circuits with strict timing such as high-speed circuits, signal propagation delay The circuit design is complicated because it requires a circuit that absorbs time fluctuations and the timing design margin needs to be verified.

  FIG. 6 shows an example of a conventional electronic device circuit that takes measures against fluctuations in the output voltage of the LSI drive power supply circuit (not a known invention in the literature). In this electronic device circuit, an intermediate voltage Vk obtained by dividing the LSI drive voltage Vout output from the series bus transistor 4 of the power supply circuit 1 by the fixed resistors R1 and R2 is led to the negative input terminal of the error amplifier 2. The positive input terminal of the error amplifier 2 is supplied with the reference voltage Vref from the reference signal source 3, and the output of the error amplifier 2 is supplied to the base terminal of the series bus transistor 4. An input voltage is supplied to the collector terminal of the series bus transistor 4, and the voltage appearing at the emitter terminal is used as the LSI drive voltage Vout.

  Now, if the LSI drive voltage Vout increases due to fluctuations in the input voltage, the difference between the intermediate voltage Vk and the reference voltage Vref decreases, so the collector current of the series bus transistor 4 decreases and the LSI drive voltage Vout drops. Act on. On the contrary, if the LSI drive voltage Vout decreases, the difference between the intermediate voltage Vk and the reference voltage Vref increases, so that the collector current of the series bus transistor 4 increases and the LSI drive voltage Vout is increased. In this way, fluctuations in the signal propagation delay time are suppressed by controlling the output voltage of the LSI drive power supply circuit to be always constant due to fluctuations in the input voltage.

  FIG. 7 shows an example of a conventional electronic device circuit that takes measures against temperature fluctuations (see, for example, Patent Document 1). The electronic device circuit uses the property shown in FIG. 8 that the operation speed becomes slower when the temperature rises and the property shown in FIG. 9 that the operation speed becomes faster when the power supply voltage rises. Is maintained at a constant value.

  If the delay value of the delay element 13 deviates from a predetermined value, the temperature measuring device 14 outputs temperature information corresponding to the temperature change to the power supply voltage control circuit 15. The power supply voltage control circuit 15 cancels the deviation corresponding to the temperature information and keeps the delay value constant.

Japanese Patent Laid-Open No. 3-85814 (2nd page, FIG. 1)

  However, the prior art shown in FIG. 6 does not deal with temperature fluctuations, and the prior art shown in FIG. 7 does not deal with voltage fluctuations.

  Therefore, even if both technologies are used together, the internal signal propagation delay time is large in an environment where temperature control is difficult due to large temperature fluctuations and no thermal convection, such as onboard electronic equipment for space use. Since it is necessary to verify and ensure the operation margin against fluctuations, the LSI drive voltage must be widely controlled, so that the LSI design taking into account fluctuations in the signal propagation delay time inside the LSI due to temperature fluctuations becomes complicated. There is a problem.

  Further, if a countermeasure circuit or a delay element has to be added in order to ensure an operation margin against a large propagation delay time fluctuation of the internal signal, there is a second problem that the degree of circuit integration is suppressed. This is a serious problem in space-mounted electronic devices that require small size and light weight.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a propagation delay time of an LSI internal signal with respect to temperature fluctuations in an electronic device having a large operating temperature range such as a space-mounted electronic device with a simple configuration without increasing volume, weight and power consumption. It is an object of the present invention to provide an electronic device circuit that can reduce LSI fluctuations, facilitate LSI design even in a high-speed circuit, and obtain stable operation.

  According to a first aspect of the present invention, an electronic device circuit including a power supply circuit that suppresses fluctuations in LSI drive voltage includes a first thermistor that is fixed in close contact with a package case of the LSI and has negative temperature characteristics. Is provided with a first resistor connected to the LSI drive voltage, a first resistor at one end, and a second resistor consisting of a fixed resistor connected at the other end to the ground. The first resistor and the second resistor An intermediate voltage obtained by dividing the LSI drive voltage is negatively fed back to the power supply circuit.

  According to a second aspect of the present invention, there is provided an electronic device circuit including a power supply circuit that suppresses fluctuations in LSI drive voltage, a first resistor including a fixed resistor having one end connected to the LSI drive voltage, and a package case of the LSI Including a thermistor fixed in close contact with the temperature positive characteristic, one end having a first resistor and the other end having a second resistor connected to the ground. The first resistor and the second resistor provide LSI. An intermediate voltage obtained by dividing the drive voltage is negatively fed back to the power supply circuit.

  According to a third aspect of the present invention, there is provided an electronic device circuit including a power supply circuit (1 in FIG. 1) that suppresses fluctuations in LSI drive voltage, and is fixed in close contact with the package case of the LSI and has a negative temperature characteristic. Including a first thermistor (Rth1 in FIG. 1), one end of which is connected to the LSI drive voltage, and a second thermistor (Rth2 in FIG. 1) that is fixed in close contact with the package case of the LSI. ) Including a first resistor at one end and a second resistor connected at the other end to the ground, and an intermediate voltage obtained by dividing the LSI drive voltage by the first resistor and the second resistor is supplied to the power supply circuit. It is characterized by negative feedback.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the power supply circuit (1 in FIG. 1) includes an intermediate voltage obtained by dividing the LSI drive voltage by the first resistor and the second resistor, and a reference voltage. An error amplifier (2 in FIG. 1) for detecting an error from (Vref in FIG. 1), an output of the error amplifier is supplied to a base terminal, a collector terminal is connected to an input power source, and an LSI drive voltage is supplied from an emitter terminal. A series bus transistor (4 in FIG. 1) is provided, and the LSI drive voltage compensates for the signal propagation delay time in the LSI at two predetermined temperatures to be the same. The ratio of the resistance values of the two resistors is set.

  The first effect of the present invention is that the temperature variation of the LSI package is detected by a temperature resistance change element such as a thermistor as a temperature sensor, and the LSI drive voltage is controlled by that signal. Compensation is integrated, so additional circuits for suppressing fluctuations in signal propagation delay time inside the LSI can be reduced, and other ICs can be eliminated by increasing circuit integration, thus improving device performance and reducing size and price Is that you can. As a result, not only on-board electronic equipment for space use, but also on industrial electronic equipment that is exposed to the same usage environment, it exhibits outstanding utility.

  In addition, the second effect is that, as a ripple effect of the first effect, it is possible to facilitate the verification of the timing margin due to temperature fluctuations in the LSI design, so that the LSI design can be simplified and the design period can be shortened. That is.

  In the present invention, the LSI package case temperature is detected by a temperature sensor having positive, negative, or positive / negative characteristics, and the LSI drive voltage is controlled by comparing the intermediate voltage from the temperature sensor with a reference voltage using an error amplifier. To do. The intermediate voltage input to the error amplifier is obtained by dividing the voltage with a thermistor that is a temperature-resistance change element.

  The resistance value of the thermistor changes depending on the LSI package case temperature, and the intermediate voltage changes. The change in the intermediate voltage and the reference voltage are compared by an error amplifier to control the LSI drive voltage. By controlling the LSI drive voltage to be high when the package case temperature is high and to lower the LSI drive voltage when the package case temperature is low, the fluctuation (delay coefficient) of the signal propagation delay time in the LSI with respect to the temperature is reduced. If the intermediate voltage is the voltage between the positive and negative thermistors connected in series and the voltage between GND, the sensitivity of fluctuation of the LSI drive voltage is improved and the control range can be increased.

  Next, embodiments of the electronic device circuit of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 1, in this electronic device circuit, an intermediate voltage Vk obtained by dividing the LSI drive voltage Vout supplied from the series bus transistor 4 of the power supply circuit 1 to the LSI 5 by the thermistor Rth1 and the thermistor Rth2 is negatively fed back to the power supply circuit 1. Thus, the signal propagation delay time of the LSI 5 with respect to the power supply fluctuation and temperature fluctuation of the LSI 5 is controlled.

  That is, the collector terminal is connected to the input voltage, and the output of the error amplifier 2 is supplied to the base terminal of the series bus transistor 4 that outputs the LSI drive voltage Vout from the emitter terminal. The reference voltage Vref from the reference signal source 3 is supplied to the plus input terminal of the error amplifier 2, and an intermediate voltage is led to the minus input terminal of the error amplifier 2.

Assuming that the open loop gain of the error amplifier 2 is A, the following equation is established.
Vout = (A / β (1 + A)) Vref
Here, β = Rth1 / (Rth1 + Rth2). For convenience, Rth1 represents the resistance value of the thermistor Rth1, and Rth2 represents the resistance value of the thermistor Rth2.

When the open loop gain A of the error amplifier is sufficiently larger than 1, the above equation is as follows.
Vout≈Vref / β = Vref (Rth1 + Rth2) / Rth1 = Vref (1+ (Rth2 / Rth1))
Therefore, the LSI drive voltage Vout is determined by the resistance value ratio of the thermistor resistance value Rth1 and the thermistor resistance value Rth2, and the LSI drive voltage can be changed by changing the resistance value. The use of a thermistor as a temperature sensor has a sufficient track record as a space component, and does not increase power consumption because it is not an active element.

  The thermistor Rth1 has a negative temperature characteristic as shown in FIG. 2, that is, a characteristic that the resistance value decreases as the temperature rises, and the thermistor Rth2 has a positive temperature characteristic as shown in FIG. 3, that is, a resistance as the temperature rises. It has the property that the value increases.

  As shown in FIG. 4, the thermistor Rth1 and the thermistor Rth2 are brought into close contact with the front or back surface of the LSI package case 6 of the LSI 5 and fixed with the heat conductive adhesive 7. Thereby, the thermistor Rth1 and the thermistor Rth2 can accurately measure the temperature of the LSI package case 6, and hence the junction temperature of the LSI 5, in the shortest time. The wire 8 in FIG. 4 is for connecting the terminals of the thermistor Rth1 and the thermistor Rth2 to the power supply circuit 1 or the ground.

  Now, if the LSI drive voltage Vout increases due to fluctuations in the input voltage, the difference from the reference voltage Vref decreases, so that the collector current of the series bus transistor 4 decreases and the LSI drive voltage Vout is lowered. Conversely, if the LSI drive voltage Vout decreases, the difference from the reference voltage Vref increases, so that the collector current of the series bus transistor 4 increases and the LSI drive voltage Vout is increased. As described above, first, the fluctuation of the signal propagation delay time of the LSI 5 is suppressed by controlling the output voltage of the power supply circuit 1 to be always constant by the fluctuation of the input voltage by the negative feedback.

  In the present embodiment, the sensitivity of adjusting the LSI drive voltage Vout with respect to temperature fluctuations is greatly improved by the positive and negative characteristics of the thermistor. In the thermistor positive characteristic, the thermistor resistance value increases as the temperature rises, and in the negative characteristic, the resistance value decreases as the temperature rises. Therefore, a thermistor having a negative characteristic is adopted as the thermistor Rth1, and a thermistor having a positive characteristic is adopted as the thermistor Rth2.

  When the temperature of the LSI package case 6 rises, the signal propagation delay time of the LSI 5 tends to increase. At this time, the resistance value of the thermistor Rth1 decreases and the resistance value of the thermistor Rth2 increases. For this reason, as is apparent from the above equation, the LSI drive voltage Vout increases and the signal propagation delay time of the LSI 5 tends to decrease.

  Conversely, when the temperature of the LSI package case 6 decreases, the signal propagation delay time of the LSI 5 tends to decrease. At this time, the resistance value of the thermistor Rth1 increases and the resistance value of the thermistor Rth2 decreases. For this reason, as is apparent from the above equation, the LSI drive voltage Vout decreases, leading to a tendency to increase the signal propagation delay time of the LSI 5.

  In this case, by adopting a thermistor with negative characteristics for the thermistor Rth1 and a thermistor with positive characteristics for the thermistor Rth2, the change in the value of (Rth2 / Rth1) with respect to temperature fluctuations becomes large. As described above, since the change in the LSI drive voltage Vout becomes large, the sensitivity of the power supply voltage adjustment can be increased and a wide range of control can be performed.

  Thus, by appropriately combining the temperature characteristics of the thermistor and the signal propagation delay time fluctuation in the LSI 5 due to the fluctuation of the LSI drive voltage Vout, it is possible to compensate for the fluctuation in the signal propagation delay time in the LSI 5 due to the temperature fluctuation. It is.

  For example, it is assumed that the ratio of the signal propagation delay time variation in the LSI 5 due to temperature variation is proportional to 0.8, when the signal propagation delay time at 25 ° C. is 1, and when + 40 ° C. is 1.2. In addition, the ratio of the signal propagation delay time fluctuation in the LSI 5 due to the fluctuation of the LSI drive voltage Vout is 1.5, the signal propagation delay time at 25 ° C. and +5.0 V is 1, 1.5 at +4.75 V, 0.7 at +5.25 V Suppose there is an inversely proportional relationship.

  In order to make the signal propagation delay time at -40 ° C the same as the signal propagation delay time at 25 ° C, the ratio of the LSI internal signal delay time variation due to the variation in LSI drive voltage Vout is 1.25, that is, the LSI drive voltage Vout is (Rth2 / Rth1) should be determined to be 4.91V at -40 ℃. This is because 0.8 × 1.25 = 1.

  Further, in order to make the signal propagation delay time at + 80 ° C. the same as the signal propagation delay time at 25 ° C., the ratio of the signal propagation delay time variation in the LSI 5 due to the variation of the LSI drive voltage Vout is 0.83, that is, the LSI (Rth2 / Rth1) may be determined so that the driving voltage Vout is 5.17 V when the driving voltage Vout is + 80 ° C. This is because 1.25 × 0.83 ≒ 1.

  FIG. 5 shows another embodiment of the electronic device circuit of the present invention. In this example, in order to divide the LSI drive voltage Vout, the combined resistance of the thermistor 9, the fixed resistor 10 and the fixed resistor 11 is adopted instead of the thermistor Rth1 in FIG. 1, and the fixed resistor 12 is substituted for the thermistor Rth2 in FIG. It is said. With such a configuration, the sensitivity of the power supply voltage adjustment is less than that of the configuration of FIG. 1, but the fluctuation of the LSI drive voltage Vout can be reduced and fine adjustment can be performed in compensating for the fluctuation of the signal propagation delay time. become.

  Not limited to FIG. 5, the fixed resistor 12 may be used instead of the thermistor Rth1 in FIG. 1, and a combined resistor of the thermistor 9, fixed resistor 10 and fixed resistor 11 may be used instead of the thermistor Rth2 in FIG. Furthermore, the combined resistance of the thermistor and the fixed resistor may not be adopted, and only one of the thermistor Rth1 or thermistor Rth2 in FIG.

  Furthermore, although the thermistor is employ | adopted as a temperature resistance change element in the above Example, this invention is not limited to this, You may use a platinum element etc. instead of a thermistor.

The block diagram which shows one Example of the electronic device circuit of this invention Diagram showing the negative characteristics of the thermistor Diagram showing the positive characteristics of the thermistor Diagram showing the mounting method of the thermistor to the LSI package case The block diagram which shows the other Example of the electronic device circuit of this invention Block diagram showing an example of the prior art Block diagram showing another example of the prior art Relationship between LSI package case temperature and internal signal propagation delay time Relationship diagram between LSI drive voltage and internal signal propagation delay time

Explanation of symbols

1 power supply circuit 2 error amplifier 3 reference signal source 4 series bus transistor 5 LSI
6 LSI package case 7 Thermal conductive adhesive 8 Wire material 9 Thermistor
10-12 Fixed resistance Rth1 thermistor Rth2 thermistor

Claims (4)

In electronic equipment circuits with power supply circuits that suppress fluctuations in LSI drive voltage,
A first resistor having a first thermistor fixed in close contact with the package case of the LSI and having a negative temperature characteristic, one end of which is connected to the LSI drive voltage;
One end is provided with the first resistor, the other end is connected to the ground, and a second resistor comprising a fixed resistor is provided,
An electronic device circuit, wherein an intermediate voltage obtained by dividing the LSI drive voltage by the first resistor and the second resistor is negatively fed back to the power supply circuit. In electronic equipment circuits with power supply circuits that suppress fluctuations in LSI drive voltage,
A first resistor comprising a fixed resistor having one end connected to the LSI drive voltage;
Including a thermistor fixed in close contact with the package case of the LSI and having a temperature positive characteristic, one end is provided with the first resistor, and the other end is provided with a second resistor connected to the ground.
An electronic device circuit, wherein an intermediate voltage obtained by dividing the LSI drive voltage by the first resistor and the second resistor is negatively fed back to the power supply circuit. In an electronic equipment circuit equipped with a power supply circuit that suppresses fluctuations in LSI drive voltage,
A first resistor including a first thermistor fixed in close contact with the package case of the LSI and having a negative temperature characteristic, one end of which is connected to the LSI drive voltage;
Including a second thermistor fixed in close contact with the package case of the LSI and having a positive temperature characteristic, the first resistor being provided at one end and the second resistor having the other end connected to the ground;
An electronic device circuit, wherein an intermediate voltage obtained by dividing the LSI drive voltage by the first resistor and the second resistor is negatively fed back to the power supply circuit. The power supply circuit includes an error amplifier that detects an error between an intermediate voltage obtained by dividing the LSI drive voltage by the first resistor and the second resistor and a reference voltage, and an output of the error amplifier is supplied to a base terminal The collector terminal is connected to the input power supply, and includes a series bus transistor that outputs the LSI drive voltage from the emitter terminal,
The ratio of the resistance value of the second resistor to the resistance value of the first resistor is set so that the LSI driving voltage is the same by compensating for the signal propagation delay time in the LSI at two predetermined temperatures. The electronic device circuit according to claim 1, wherein:

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