摘要:
According to an image sensor disclosed, a pixel circuit includes a photo-diode 14 for generating a photo-electric conversion voltage which corresponds to an input optical level, a transistor 11 which is activated in response to a Reset signal RST, to initialize the photo-diode 14 from a power supply VDD, a transistor 12 which, when connected between the power supply VDD and a bit line BL, amplifies a photo-electric conversion voltage and outputs it onto the bit line BL, and a transistor 13 which is activated by a word-line readout control signal WL, to interconnect the transistor 12 and the bit line BL, in which the transistor 11 is of a depletion type.
摘要:
The image sensor of the present invention performs two exposures of differing exposure times, holds the signal charge that is generated in photodiode 1 in the first exposure period in pixel interior capacitance 4 that is provided inside pixels and integrates the signal charge that is generated in photodiode 1 in the second exposure period with the first signal charge inside the pixels and executes readout, whereby the white (overexposed) portions that occur in the first exposure period are compensated by information of the second exposure period, and black (underexposed) portions that occur in the second exposure period are compensated by information of the first exposure period, and an image is obtained having wide dynamic range with respect to the amount of light in which underexposure and overexposure are mitigated.
摘要:
An N well is disposed in the upper surface of a P type substrate, a gate insulating film and a gate electrode are disposed thereon, and the gate electrode is connected to a gate terminal. Two p+ diffusion regions are placed in two areas in the surface of the N well sandwiching the gate electrode, and the p+ diffusion regions are connected to a ground potential wiring. Further, an n+ diffusion region is disposed in the surface of the N well, and is connected to a well terminal. Accordingly, capacitance is generated between the gate electrode and the N well of a varactor element. When the potential of the gate terminal is decreased, the two p+ diffusion regions absorb positive holes serving as minority carriers from a channel region.
摘要:
Deterioration in frequency stability with time in a conventional piezoelectric oscillator using an accumulation type MOS capacitance element is improved. A P-channel transistor type or an N-channel transistor type is used as a MOS capacitance element in a variable capacitance circuit used in a piezoelectric oscillator. A bias voltage is applied between P-type or N-type extraction electrodes formed in source and drain regions and an N-type extraction electrode provided in an N-well region or a P-type extraction electrode provided in a P-well region. Instability in the MOS capacitance element with time is thus eliminated.
摘要:
Deterioration in frequency stability with time in a conventional piezoelectric oscillator using an accumulation type MOS capacitance element is improved. A P-channel transistor type or an N-channel transistor type is used as a MOS capacitance element in a variable capacitance circuit used in a piezoelectric oscillator. A bias voltage is applied between P-type or N-type extraction electrodes formed in source and drain regions and an N-type extraction electrode provided in an N-well region or a P-type extraction electrode provided in a P-well region. Instability in the MOS capacitance element with time is thus eliminated.
摘要:
There is disclosed a black-level signal generation circuit for use with a CMOS-based active pixel image sensor. This black-level signal generation circuit delivers a black-level signal of a constant level at all times. The black-level signal generation circuit is equivalent in circuit configuration to any one of pixels forming an effective pixel array and any one of readout portions for reading out signals from the pixels. A photodiode is maintained in a reset state. MOS transistors whose corresponding MOS transistors are turned ‘ON/OFF’ in any one of the pixels and any one of the readout portions are all kept in ‘ON’ state. Thus, the black-level signal generation circuit can constantly produce a black-level signal equivalent in level to the pixel signal delivered when no light is incident on the effective pixels.
摘要:
There is disclosed an image sensor wherein the dispersion in threshold voltages of a transistor constituting a source follower for outputting a signal is compensated. The disclosed image sensor is provided with a coupling capacitor to which an output voltage of a pixel is applied through a transistor and with a transistor of a source follower to read out a voltage at the node S/Hn of the coupling capacitor. The image sensor is so configured that a drain of a transistor is used as a power supply voltage and the transistor is turned on, causing a node S/Hn pre-charged to the power supply voltage, and then the transistor is turned on, causing the voltage of the node S/Hn to be clamped on a sum of a definite voltage and a threshold voltage of the transistor, and further the transistor is turned on, causing an output voltage generated when a pixel is exposed to light to be added to the capacitor, and by restoring the transistor to a power supply voltage of the drain and by again turning the transistor on, an output voltage generated when a pixel is unexposed to light is applied to the capacitor.
摘要:
A P type substrate is provided on a surface thereof with varactor elements. The varactor element has an N well formed on the surface of the P type substrate, and a gate insulating film is formed on the N well, with a polysilicon layer formed further thereon. On the other hand, the varactor element has an N well formed on the surface of the P type substrate, and a gate insulating film, greater than the gate insulating film in thickness, is formed on the N well. The polysilicon layer is then formed on the gate insulating film. Furthermore, the polysilicon layer is connected to a gate terminal, while the N well is connected to an S/D terminal via N+ diffusion layers.
摘要:
In a semiconductor integrated circuit, a control transistor 4 and a potential clamp circuit 9 are arranged between a power supply line 2 and a virtual power supply line 3. Even in a sleeve mode where the control transistor 4 is turned off, the potential clamp circuit 9-1 clamps the virtual power supply line 3 at a certain potential to hold a potential state (high level or low level) of each node of a logical circuit. At this time, each FET forming the logical circuit is applied with a back bias so that a threshold voltage Vt becomes higher than that in an active mode. Therefore, a leakage current can be decreased. In the semiconductor integrated circuit, the threshold voltage Vt of the control transistor 4 can be selected to be equal to that of one FET of the complementary FET forming the logical circuit. Therefore, the layout area and the number of manufacturing steps can be reduced.
摘要:
A driver circuit comprising (i) a pair of complementary MOS (CMOS) transistors connected in series and receiving an identical input signal, and (ii) a pair of control transistors changing a threshold voltage state of each of the pair of CMOS transistors by applying a plurality of voltages to a body terminal of each of the pair of CMOS transistors depending upon the ON/OFF state of each of the pair of CMOS transistors. Such a driver circuit is capable of reconciling a high-speed operation with a low power consumption under low power supply voltage conditions.