Semiconductor integrated circuit, sensor reader, and sensor readout method
AssigneeMitsubishi Electric Corporation
InventorsTomokazu OGOMI, Takayuki NAKAI
Life of this patent
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Abstract
In a sensor reader, an IC chip has a function for amplifying and outputting a sensor signal from each sensor element included in a sensor array, and includes a plurality of channel amplifiers connected each of the sensor elements. When an output switch is closed and the IC chip is in the outputting state, channel switches operate sequentially, and sensor amplification signals are output sequentially from the channel amplifiers. When the output switch is open and the IC chip is in the non-outputting state, a bias current of an operational amplifier of the channel amplifier is decreased, the IC chip is set to a low power consumption state, and gain of the operational amplifier is decreased.
Claims16
A semiconductor integrated circuit comprising:
- a plurality of first amplifiers, each first amplifier of the plurality of first amplifiers amplifying a sensor signal input from a corresponding sensor element of a plurality of sensor elements;
- a plurality of first switches, each first switch of the plurality of first switches connecting to an output of the first amplifier to perform switching between conducting and blocking of the output;
- a second switch to perform switching of a sensor amplification signal output via the first switch from the first amplifier, the switching of the second switch being between closing to conduct to, and opening to block, an external output terminal;
- and
- a control circuit to cause:
- when the second switch is closed, operating of the first switches so that the sensor amplification signals output from the plurality of first amplifiers are output sequentially one at a time;
- and
- when the second switch is open, setting a bias current and a gain of at least one first amplifier of the plurality of first amplifiers to second setting values that are lower than first setting values, the first setting values being the bias current and the gain when the second switch is closed.
A sensor readout method, comprising:
- an amplifying step of amplifying, by a plurality of amplifiers, sensor signals input from a plurality of sensor elements;
- a signal switching step of, for each of a plurality of first switches connected to a corresponding amplifier of the plurality of amplifier, opening the first switch to block connection, and closing the first switch to make connection, for sequential output of sensor amplification signals amplified in the amplifying step;
- an output switching step of opening a second switch to block transmission, and closing the second switch to allow transmission, of the sensor amplification signals output via the first switch to an external output terminal;
- and
- an amplifier setting change step of, when transmission is blocked in the output switching step, setting a bias current and a gain of at least one of the amplifiers to second setting values that are lower than first setting values, the first setting values being used when transmission is allowed to the external output terminal.
Dependencies are inferred from the claim text.