Abstract: A circuit for readout from for readout from a focal plane array having a number of pixels, includes, for each one pixel, an adaptive photodetector load circuit coupled to a detector for the one pixel, a trans-impedance amplifier, the detector being AC coupled to the trans-impedance amplifier, a comparator component, receiving an AC coupled output of the trans-impedance amplifier and comparing the AC coupled output to a predetermined threshold, a sample and hold ring comprising a number charge storage components connected in parallel, each one charge storage component comprising a capacitor in series with an enabling three point switching component and a pulse detection logic circuit receiving an output of the comparator component.

Abstract: A circuit for readout from for readout from a focal plane array having a number of pixels, includes, for each one pixel, an adaptive photodetector load circuit coupled to a detector for the one pixel, a trans-impedance amplifier, the detector being AC coupled to the trans-impedance amplifier, a comparator component, receiving an AC coupled output of the trans-impedance amplifier and comparing the AC coupled output to a predetermined threshold, a sample and hold ring comprising a number charge storage components connected in parallel, each one charge storage component comprising a capacitor in series with an enabling three point switching component and a pulse detection logic circuit receiving an output of the comparator component.

Abstract: Methods and apparatus to provide, from data from a single sensor, high-resolution imagery at a first frame rate, such as typical video frame rate, and lower-resolution imagery at a second frame rate, which is higher than the first rate. In one embodiment, the first frame rate data can be viewed by a user and the second frame rate data can be processed to identify an event of interest, such as pulsed light.

Abstract: A method for sensing using a multi-band photovoltaic detector, the method including biasing the photovoltaic detector using a bias voltage at a mid-point of a detector substrate bias voltage range, selecting a first band of the multi-band photovoltaic detector, sensing a first current from a first diode of the multi-band photovoltaic detector, the first diode being associated with the first band, selecting a second band of the multi-band photovoltaic detector; and sensing a second current from a second diode of the multi-band photovoltaic detector, the second diode being associated with the second band.

Abstract: A radiation detector having a pair of adjacent mesas disposed on a common layer. The common layer comprises a first semiconductor layer having a first conductivity type and an energy bandgap responsive to radiation in a first spectral region. Each of the mesas comprises: a second semiconductor; and a third semiconductor layer disposed on the second semiconductor layer having the first conductivity type and an energy bandgap responsive to radiation in a second spectral region. The second semiconductor layer may have a conductivity type opposite the first conductivity type or the three layers may provide an nBn or pBp structure. The third semiconductor layer of the second mesa produces minority carriers, in response to the radiation in the second spectral region, flowing as unwanted carriers into the common layer towards the first mesa. A barrier region is disposed in the common layer to prevent the unwanted carriers from passing from the second mesa to the first mesa.

Abstract: A method for sensing using a multi-band photovoltaic detector, the method including biasing the photovoltaic detector using a bias voltage at a mid-point of a detector substrate bias voltage range, selecting a first band of the multi-band photovoltaic detector, sensing a first current from a first diode of the multi-band photovoltaic detector, the first diode being associated with the first band, selecting a second band of the multi-band photovoltaic detector; and sensing a second current from a second diode of the multi-band photovoltaic detector, the second diode being associated with the second band.

Abstract: Methods and apparatus to provide, from data from a single sensor, high-resolution imagery at a first frame rate, such as typical video frame rate, and lower-resolution imagery at a second frame rate, which is higher than the first rate. In one embodiment, the first frame rate data can be viewed by a user and the second frame rate data can be processed to identify an event of interest, such as pulsed light.

Abstract: A unit cell (10) of a readout integrated circuit is constructed and operated so as to temporally align an image obtained in a first spectral band with a an image obtained in a second spectral band. A method operates, during a frame period, to sub-frame average a first signal detected in the first spectral band by a multi-spectral detector (12), to sub-frame average a first signal detected in the second spectral band by the multi-spectral detector, and to sub-frame average a second signal detected in the first spectral band by the multi-spectral detector. The method then reads out the sub-frame averaged signals for each spectral band. The sub-frame averaged may be read out simultaneously from the unit cell.

Abstract: A focal plane array (FPA) of infrared (IR) radiation detectors (20), such as an array of microbolometers, includes an active area (20A) containing a plurality of IR radiation detectors, a readout integrated circuit (ROIC) (12) that is mechanically and electrically coupled to the active area and, disposed on the ROIC, a plurality of heater elements (30A) that are located and operated so as to provide a substantially uniform thermal distribution across at least the active area. The FPA further includes a plurality of temperature sensors (30B), individual ones of which are spatially associated with one of the heater elements for sensing the temperature in the vicinity of the associated heater element for providing closed loop operation of the associated heater element.

Abstract: An electronic circuit device for driving a load comprises a load terminal, a control terminal and a power terminal for connection to a source of electric power. The load terminal may be in an emitter or a source circuit of the circuit device, and connects to a power supply return terminal by means of three electric elements connected in parallel, namely, the capacitance of a load, a bias current supply, and a current bypass. A voltage sensor is connected between the control terminal and the load terminal for sensing a voltage drop developed between the control terminal and the load terminal. The voltage sensor it is operative to activate the bypass to conduct current in parallel with current flow of the current source in the situation wherein the voltage drop exceeds a threshold. Thereby, the circuit device drives the load in one direction, and the current source and the bypass drive the load in the opposite correction.

Abstract: An IR-FPA (10) having a plurality of radiation detectors (2a) and a multipurpose ROIC (2) is disclosed. The radiation detectors (2a) are organized as a two dimensional array. The multipurpose ROIC (2) includes a plurality of readout circuit unit cells, individual ones of which are coupled to individual radiation detectors (2a) for receiving electrical signals therefrom. Each of the readout circuit unit cells operates in one of a first mode to provide a corrected m frame averaged output signal (Vout.sub.THPF) or, a second mode to provide a subframed averaged output signal (Vout.sub.2). In the first operating mode, a high pass filtering circuit subtracts a low frequency charge pedestal from the electrical signal to form the corrected m frame averaged output (Vout.sub.THPF).

Abstract: An imaging device (10) has a plurality of unit cells that contribute to forming an image of a scene. The imaging device includes a layer of semiconductor material (16), for example silicon, that has low noise photogate charge-mode readout circuitry (20, 21, 26, 28) (e.g., CCD or CMOS readout circuitry and structures) that is disposed upon a first surface (18) of the layer. A second, opposing surface of the layer is a radiation admitting surface of the layer. The layer has a bandgap selected for absorbing electromagnetic radiation having wavelengths shorter than about one micrometer and for generating charge carriers from the absorbed radiation. The generated charge carriers are collected by the photogate charge-mode readout circuitry. A thermal sensing element (22) is disposed above and is thermally isolated from the first surface of the layer. The thermal sensing element may be, by example, one of a bolometer element, a pyroelectric element, or a thermopile element.

Abstract: An integrated two-color staring focal plane array is comprised of rows and columns of photodetector unit cells (10), each being capable of simultaneously integrating photocurrents resulting from the detection of two spectral bands. A readout circuit (20) in accordance with this invention performs a subtraction function, and includes a differential charge-sensing amplifier (22) in a one-per-column arrangement. The amplifier works in cooperation with circuitry (M5) located in each unit cell. The subtraction function is employed to create a separate Band1 signal from a Band2 and (Band1+Band2) signals generated by each simultaneous two-color detector (1). One significant advantage of the disclosed circuit embodiment is that it offers low spectral crosstalk between the two spectral bands.

Abstract: A high charge capacity readout cell in a hybrid focal plane detector array on a complementary metal oxide semiconductor integrated circuit chip. An input transistor that provides a buffer for the detectors of the array, couples to a source of bias voltage, which controls the operation of the transistor. An integrating capacitor uses a variable source of terminating voltage to increase the amount of charge it integrates. A read signal causes an output transistor to read the charge from the capacitor to a readout line and to initialize the capacitor. The termination voltage of the integrating capacitor is changed during the time that the detector current is integrated, thus increasing the change in total voltage across the capacitor. This allows a greater amount of charge to be integrated with the capacitor which improves the signal-to-noise ratio of the focal plane array.

Abstract: A Source-Follower-per-Detector (SFD) unit cell [12'], a two dimensional array [30] of same and a method of operating the two dimensional array. Each unit cell is constructed with but three transistors [14, 16, 22] and is coupled to an associated radiation detector [10] for receiving an output signal therefrom. A method includes a first step of (a) reading out a first row (N) of unit cells by asserting a first row enable signal for causing each of the unit cells of the row (N) to impress an electrical signal onto an associated output signal line. The electrical signal has a magnitude that is a function of the associated detector output signal. The method includes an additional step of (b) simultaneously resetting another row of unit cells each of which has a reset input coupled to and responsive to the assertion of the first row enable signal line.

Abstract: A readout circuit for use with a focal plane array that employs a single transistor in each unit cell and a single capacitive feedback transimpedance amplifier to process the outputs of each column of detector elements of the array. The capacitive feedback transimpedance amplifiers extract the signals associated with the pixels along a particular row of the array. The present invention permits high performance readouts to be constructed with very little circuitry in the unit cells. Only a single minimum sized transistor switch is required in each unit cell to perform readout and reset functions for the array. In the disclosed embodiment, the readout circuit comprises an array of unit cells, each cell comprising a detector input circuit, a single transistor and a single charge storage capacitor. Row address circuits are coupled to the cells in each row of the array. A plurality of capacitive feedback transimpedance amplifiers are coupled to the cells in each column of the array.

Abstract: A Source-Follower-per-Detector (SFC) unit cell [12], a two dimensional array [30] of same and a method of operating the two dimensional array. Each unit cell is constructed with but three transistors [14, 16, 22] and is coupled to an associated radiation detector [10] for receiving an output signal therefrom. A method includes a first step of (a) reading out a first row (N) of unit cells by asserting a first row enable signal for causing each of the unit cells of the row (N) to impress an electrical signal onto an associated output signal line. The electrical signal has a magnitude that is a function of the associated detector output signal. The method includes an additional step of (b) simultaneously resetting another row of unit cells each of which has a reset input coupled to and responsive to the assertion of the first row enable signal line.