Semiconductor device
View Patent ↗An infrared radiation image pickup apparatus, the image pickup elements of which are each formed by a bolometer, is disclosed. The resistance value of the bolometer outside a preset range in a given readout circuit associated with a given image pickup element does not affect other readout circuits performing parallel operations with the readout circuit. The readout circuit includes an OP amplifier 5 , a non-inverting input terminal of which is connected to an output of a D/A converter 7 , a MOS transistor 4 , and a switch 6 . The MOS transistor 4 has a gate connected to an output terminal of the OP amplifier 5 and has a source connected to an inverting input terminal of the OP amplifier 5 and connected via a horizontal switch 3 to a bolometer 1 . The switch 6 is connected between the gate and the source of the MOS transistor 4 . The D/A converter 7 receives data for applying a bias voltage to the bolometer 1 , and outputs the bias voltage. In case at least the output voltage of the D/A converter 7 is outside a preset range, that is, in case input data to the D/A converter 7 is preset data, the input data is decoded by a decoder 8 , and the horizontal switch 3 is opened by an output of a NOR circuit 9 a , while the switch 6 is short-circuited.
1. A semiconductor apparatus comprising:
a plurality of resistance measurement elements, each converting a physical quantity into a resistance value;
a first switch device connected to one of said resistance measurement elements to permit electrical current to pass through said resistance measurement element;
a bias circuit that applies a bias voltage to one of said resistance measurement elements; and
an integrating circuit that integrates a current flowing through one of said resistance measurement elements to store the integrated current;
said semiconductor apparatus detecting changes in a resistance value of one of said resistance measurement elements, based on the current stored in said integrating circuit, thereby indirectly measuring said physical quantity; wherein
said bias circuit includes;
an OP amplifier, having a non-inverting input terminal connected to a bias voltage supplying terminal;
a MOS transistor, having a gate connected to an output terminal of said OP amplifier and having a source connected to an inverting input terminal of said OP amplifier and connected via said first switch device to one of said resistance measurement elements; and
a second switch device connected between the gate and the source of said MOS transistor; and wherein
there is provided a switch control circuit that performs control so that, when a resistance measurement element, the resistance value of which is outside a preset range, is selected, said first switch device is opened and said second switch device is short-circuited.
2. The semiconductor apparatus according to claim 1 further comprising:
a digital-to-analog converter that outputs a voltage transmitted to said bias voltage supply terminal, based on data of resistance values of said resistance measurement elements measured in advance and saved;
said switch control circuit performing control so that, when said data is preset data, said first switch device is opened and said second switch device is short-circuited.
3. The semiconductor apparatus according to claim 2 wherein said switch control circuit performs control for opening said first switch device during a period said integrating circuit is not performing an integrating operation.
4. The semiconductor apparatus according to claim 2 further comprising:
a third switch device provided in a bias current path from said bias circuit to said resistance measurement element;
said switch control circuit performing control for opening said third switch device during a period said integrating circuit is not performing an integrating operation.
5. The semiconductor apparatus according to claim 4 wherein said switch control circuit performs control for short-circuiting said second switch device during the period said integrating circuit is not performing an integrating operation.
6. The semiconductor apparatus according to claim 1 wherein said switch control circuit performs control for opening said first switch device during a period said integrating circuit is not performing an integrating operation.
7. The semiconductor apparatus according to claim 6 wherein said switch control circuit performs control for short-circuiting said second switch device during the period said integrating circuit is not performing an integrating operation.
8. The semiconductor apparatus according to claim 1 further comprising:
a third switch device provided in a bias current path from said bias circuit to said resistance measurement element;
said switch control circuit performing control for opening said third switch device during a period said integrating circuit is not performing an integrating operation.
9. The semiconductor apparatus according to claim 8 wherein said switch control circuit performs control for short-circuiting said second switch device during the period said integrating circuit is not performing an integrating operation.
10. The semiconductor apparatus according to claim 1 wherein said resistance measurement element is a thermo-electric transducing element which receives to sense infrared radiations.
11. A measurement apparatus comprising:
a plurality of objects to be biased, each converting a physical quantity into a resistance value;
a first switch device connected to one of said objects to be biased to permit electrical current to pass through said object to be biased;
a bias circuit that applies a bias voltage to one of said objects to be biased; and
an integrating circuit that integrates a current flowing through one of said objects to be biased to store the integrated current;
said measurement apparatus detecting changes in a resistance value of one of said objects to be biased, based on the current stored in said integrating circuit, to indirectly measure said physical quantity; wherein
said bias circuit includes;
an OP amplifier, having a non-inverting input terminal connected to a bias voltage supplying terminal;
a MOS transistor, having a gate connected to an output terminal of said OP amplifier and having a source connected to an inverting input terminal of said OP amplifier and connected via said first switch device to one of said objects to be biased; and
a second switch device connected between the gate and the source of said MOS transistor; and wherein
there is provided a switch control circuit that performs control so that, when the object to be biased, a resistance value of which is outside a preset range, is selected, said first switch device is opened and said second switch device is short-circuited.
12. The measurement apparatus according to claim 11 further comprising:
a digital-to-analog converter that outputs a voltage supplied to said bias voltage supply terminal, based on data of resistance value of at least one of said objects to be biased measured in advance and saved;
said switch control circuit performing control so that, when said data is preset data, said first switch device is opened and said second switch device is short-circuited.
13. The measurement apparatus according to claim 12 wherein said switch control circuit performs control for opening said first switch device during a period said integrating circuit is not performing an integrating operation.
14. The measurement apparatus according to claim 13 wherein said switch control circuit performs control for short-circuiting said second switch device during the period said integrating circuit is not performing an integrating operation.
15. The measurement apparatus according to claim 11 wherein said switch control circuit performs control for opening said first switch device during a period said integrating circuit is not performing an integrating operation.
16. The measurement apparatus according to claim 15 wherein said switch control circuit performs control for short-circuiting said second switch device during the period said integrating circuit is not performing an integrating operation.
17. The measurement apparatus according to claim 11 wherein said object to be biased is a thermo-electric transducing element which receives to sense infrared radiations.