Semiconductor integrated circuit and system guaranteeing proper operation under low-temperature condition

Abstract

A semiconductor integrated circuit includes a measurement circuit configured to detect a measuring quantity dependent on temperature, and a heating circuit configured to generate heat in response to a detection, by the measurement circuit, of the measuring quantity indicating that the temperature is lower than a predetermined level.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:

FIG. 1 is a drawing showing the circuit configuration of a first embodiment of a circuit system according to the present invention;

FIG. 2 is a drawing showing an example of the configuration of a frequency comparing circuit and a temperature-measurement-purpose ring oscillator;

FIG. 3 is a flowchart showing the procedure of the heating process performed in the system; and

FIG. 4 is a drawing showing the circuit configuration of a second embodiment of a circuit system according to the present invention.

Claims

1. A semiconductor integrated circuit, comprising: a measurement circuit configured to detect a measuring quantity dependent on temperature; anda heating circuit configured to generate heat in response to a detection, by the measurement circuit, of the measuring quantity indicating that the temperature is lower than a predetermined level.

2. The semiconductor integrated circuit as claimed in claim 1, wherein the measurement circuit includes: a ring oscillator; anda frequency comparing circuit configured to compare a frequency of a clock signal supplied from an exterior with a frequency of an oscillating signal of the ring oscillator,wherein the heating circuit is configured to generate heat in response to a detection by the frequency comparing circuit that the frequency of the oscillating signal is higher than the frequency of the clock signal.

3. The semiconductor integrated circuit as claimed in claim 1, wherein the heating circuit is configured to generate heat by consuming an electric current through operations that cause a signal level to alternate between HIGH and LOW.

4. The semiconductor integrated circuit as claimed in claim 1, further comprising a memory controller configured to repeatedly transmits commands to be executed by a memory in response to a detection, by the measurement circuit, of the measuring quantity indicating that the temperature is lower than a predetermined level.

5. The semiconductor integrated circuit as claimed in claim 1, wherein the heating circuit is configured to suspend the generation of heat in response to a detection, by the measurement circuit, of the measuring quantity indicating that the temperature is higher than a predetermined level.

6. The semiconductor integrated circuit as claimed in claim 1, further comprising a core circuit configured to start operating in response to a detection, by the measurement circuit, of the measuring quantity indicating that the temperature is higher than a predetermined level.

7. A circuit system, comprising: a first semiconductor integrated circuit including a first measurement circuit configured to detect a measuring quantity dependent on first temperature and a first heating circuit configured to generate heat in response to a detection, by the first measurement circuit, of the measuring quantity indicating that the first temperature is lower than a predetermined level; anda second semiconductor integrated circuit including a second measurement circuit configured to detect a measuring quantity dependent on second temperature and a second heating circuit configured to generate heat in response to a detection, by the second measurement circuit, of the measuring quantity indicating that the second temperature is lower than the predetermined level,wherein a core circuit of the first semiconductor integrated circuit and a core circuit of the second semiconductor integrated circuit are configured to start operating in response to simultaneous detections, by the first measurement circuit and the second measurement circuit, of measuring quantities indicating that the first temperature is higher than the predetermined level and that the second temperature is higher than the predetermined level.

8. A circuit system, comprising: a first semiconductor integrated circuit;a second semiconductor integrated circuit;a first measurement circuit configured to measure a temperature of the first semiconductor integrated circuit;a second measurement circuit configured to measure a temperature of the second semiconductor integrated circuit;a heating device configured to heat the first semiconductor integrated circuit in response to a detection by the first measurement circuit that the temperature of the first semiconductor integrated circuit is lower than a predetermined level; anda heating device configured to heat the second semiconductor integrated circuit in response to a detection by the second measurement circuit that the temperature of the second semiconductor integrated circuit is lower than the predetermined level,wherein the first semiconductor integrated circuit and the second semiconductor integrated circuit are configured to start operating in response to simultaneous detections by the first measurement circuit and the second measurement circuit that the temperature of the first semiconductor integrated circuit is higher than the predetermined level and that the temperature of the second semiconductor integrated circuit is higher than the predetermined level.

9. The circuit system as claimed in claim 8, wherein the heating device is a Peltier device.

10. A method of driving a semiconductor integrated circuit, comprising: detecting a measuring quantity dependent on a temperature of a semiconductor integrated circuit;heating the semiconductor integrated circuit in response to a detection of the measuring quantity indicating that the temperature is lower than a predetermined level;stopping heating the semiconductor integrated circuit in response to a detection of the measuring quantity indicating that the temperature is higher than the predetermined level; andcausing the semiconductor integrated circuit to start operating in response to a detection of the measuring quantity indicating that the temperature is higher than the predetermined level.