Miscellaneous active electrical nonlinear devices – circuits – and – External effect – Temperature
Patent
1997-09-02
1999-03-23
Wells, Kenneth B.
Miscellaneous active electrical nonlinear devices, circuits, and
External effect
Temperature
327262, 327378, 374183, 3241581, H03K 342
Patent
active
058865640
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a temperature compensation circuit to be used in a semiconductor IC, and more particularly, a temperature compensating circuit of a variable delay circuit in a digital integrated circuit (IC) which can compensate a signal transmission delay time by temperature.
BACKGROUND OF THE INVENTION
In an IC test apparatus having a plurality of test signal supply paths (hereinafter "channel") which provide test pattern signals to a plurality of pins of the IC to be tested, delay times among the channels should be matched. Thus, each delay time per each channel has to be adjusted to be same delay time and such adjusted delay time should be maintained for a long period of time. However, if IC circuits are employed to form each channel to decrease the size of the test apparatus, there arises a problem in that, in such IC circuits, delay times for propagation of signals vary depending on temperature changes.
Particularly, if the ICs with CMOS (complementary metal-oxide semiconductor) structure are used, such a change in the delay time conspicuous since the heat generation is completely different whether it is in rest or in operation. Namely, in the CMOS circuit, in a non-operational state (when no signals are generated therefrom), the amount of a current consumed therein is very small. In contrast, if the CMOS ICs are in an operational state (when a logic of the signal is inverted), they consume the current several thousand times as much as they do in the non-operational state. Thus, in the ICs with the CMOS structure, the amounts of the currents consumed therein are largely different between the operational and non-operational states. Accordingly, self-heating values in each state are different. If the operational and non-operational states are irregularly happen, the temperature of the IC chips increases only when they are in the operational state, which is impossible to control. As a result, mismatches of the delay times are caused between the channels.
In order to solve the above problem, the conventional device has employed ICs having temperature compensatory function for a circuit aiming to maintain the delay times in a certain period.
FIG. 9 shows a structure of the conventional IC having a temperature compensatory function therein. In FIG. 9, reference numeral 10 is a chip forming an IC. The chip 10 consists of a target circuit 11 to form a channel of the IC test apparatus and its delay time is to be maintained in a certain period, a temperature sensor 12 formed in a vicinity of the target circuit 11, a plurality of heater elements H dispersed in a vicinity of the target circuit 11, and a plurality of switch elements 13 for turning on/off a current applied to the heater elements H. In the conventional device, detecting signals from the temperature sensor 12 are given to a heater control device 20, control output signals from the heater control device 20 are given to the switch elements 13 wherein the current applied to the heater H is turned on/off so as to consistently maintain the temperature inside the chip 10.
Namely, when the target circuit 11 is in the non-operational state, the heater elements H is heated by a current (which is the same current as consumed in the target circuit 11) applied thereto. Then, an operation of the target circuit 11 begins so as to turn off the current applied to the heater elements H when a surrounding temperature of the target circuit 11 increases.
When a signal is given to the target circuit 11 and its operation begins, the temperature of the circuit increases. Then, the temperature sensor 12 detects the temperature change and shuts off the current applying to the heater elements H, causing the time delay. However, this conventional structure has a disadvantage in that: since the detection of the temperature change is subject to the temporary increase of the temperature inside the chip 10, it causes a fluctuation in the delay times.
Further, because of the delay in the detection, the currents are applied to both of the
REFERENCES:
patent: 4196361 (1980-04-01), Nakata
patent: 4980586 (1990-12-01), Sullivan et al.
patent: 5300968 (1994-04-01), Hawkins
patent: 5336939 (1994-08-01), Eitrheim et al.
Masuda Noriyuki
Sato Masatoshi
Advantest Corp.
Wells Kenneth B.
LandOfFree
Temperature compensation circuit for IC chip does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Temperature compensation circuit for IC chip, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Temperature compensation circuit for IC chip will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2130197