摘要:
A calibrated sensing system is provided in accordance with the teachings of this invention for sensing charge in a storage medium, such as a storage capacitor, coupled to an access or bit/sense line which compensates for most sources of variability in the storage medium and in the access line. In the system, the unknown charge stored in the storage medium is transferred to a first capacitor or potential well via the access line. A high charge state of the storage medium is written into the storage medium and known fractional packets of charge are prepared therefrom, transferred selectively to a second capacitor or potential well and compared with the unknown charge in the first potential to determine the relative level of the unknown charge that was stored in the storage medium. By selectively using two or more fractional packets of charge multilevel sensing is performed.
摘要:
A bucket brigade circuit is described for generating a sequence of packets of charge carriers of the form Q.sub.R /2, Q.sub.R /4, Q.sub.R /8....Q.sub.R /2.sup.N where N is an integer. The charge packets thus generated can be employed in combinations in either digital-to-analog or analog-to-digital converters. The charge generation circuit requires two equal capacitors which are used for charge redistribution. To obtain accurate quantities of charge in the generated charge packets the capacitors employed should be large, however the use of large capacitors results in low operating speed because of the large charge transfer time constants involved. The described circuit provides a scheme to reduce charge transfer time constants and therefore obtain greater speed while still permitting the use of large capacitors for high accuracy. The circuit includes a small coupling capacitor connected in series with one of the charge redistribution capacitors to produce a total capacitance which is equal to or smaller than the coupling capacitance. The sequence of charge carriers produced by the circuit can be injected into either a bucket brigade circuit or a charge-coupled-device circuit for use, for example, in digital-to-analog and analog-to-digital converters.
摘要:
A methodology is provided for reducing an arbitrary Boolean logic expression to static CMOS circuits by the use of a general matrix of P channel devices and N channel devices which are interconnected in accordance with the terms of Boolean logic expressions derived from a truth table. More specifically, from a Boolean expression a sum-of-products expression giving the 1 binary data outputs of a truth table having a 0 input is found. This is accomplished by complementing, or barring, the literals which are a binary 1 when the output is 1 and leaving true or unbarred the literals that are a binary 0. Then each input of a given product term is applied to the control gate of a P channel device, which devices are connected in series with one end tied to a source of potential and the other end of the series circuit connected to an output terminal. Each product term is arranged in parallel with other P channel device series circuits to form one half of a complete logic matrix. Similarly, for the other half of the matrix, a sum-of-products expression giving the binary 0 outputs of a truth table having a binary 1 for an input is found. Each input of a given product term is applied to the control gate of an N channel device, which devices are connected in series with one end tied to a potential reference point, such as ground, and the other end of the series circuit is connected to the output terminal. Each product term is arranged in parallel with other N channel device series circuits.
摘要:
An SPS CCD memory system is provided wherein a single tap, preferably a storage node, on an input serial or shift register is connected to the input of a plurality of parallel shift registers through a fan out circuit and the output of the plurality of parallel shift registers is connected to a single tap, preferably a storage node, on an output serial or shift register through a fan in circuit.
摘要:
A novel precharge circuit is provided for dynamic CMOS logic circuits which are immune to leakage currents and reduce overall power consumption. The circuit comprises a precharge transistor for precharging a node to a high voltage level indicting a first logic state during a standby mode. Thereafter, during an active mode, the node may or may not be discharged by connected logic circuitry. If the node is discharged, then an additional transistor is provided to inhibit the precharging of the already charged node during a subsequent standby mode. Similarly, if the node is not discharged, a small keeper transistor is provided to keep the node at a fully precharged level.
摘要:
A logic system including a first logic block for providing first differential outputs; a second logic block, identical to the first logic block, for providing second differential outputs; a fault detecting device, coupled to the first logic block, for detecting a fault in the first differential outputs; and a selecting device, coupled to the first and second logic blocks and to the fault detecting device, for selecting an output of one of the first and second logic blocks depending on whether the fault detecting device detects a fault.
摘要:
A system for testing a differential logic network is provided which includes a differential exclusive OR circuit having a plurality of inputs for receiving complementary signals from the differential logic network and first and second output terminals and means, e.g., a conventional exclusive OR circuit, for determining the voltage difference between the first and second output terminals to indicate the presence or absence of a fault or error in the differential logic network under test.
摘要:
Storage systems are provided with memory cells made of devices having different voltage thresholds for storing information permanently or semipermanently. The devices are arranged adjacent to each other and communicating with a diffusion region in a semiconductor substrate. Information is sensed by detecting the charge transferred from a selected cell to the diffusion region. In an embodiment of the invention, a P-type substrate has an N+ diffusion region formed therein with a plurality of adjacent and parallelly arranged word lines insulated from the substrate and disposed adjacent to the N+ diffusion region. A P+ region, preferably implanted into the substrate, is disposed under selected segments of the word lines to provide devices having a first or high threshold voltage magnitude. The remaining devices which are not associated with a P-30 region have a second or low threshold voltage magnitude. By applying a voltage of the same magnitude to each of the word lines, potential wells are formed which are filled by charge or carriers from the diffusion region. Since the potential wells associated with the high threshold devices hold less charge than do the low threshold devices, a charge or voltage sensing circuit connected to the N+ diffusion region is used to detect the amount of charge flowing between the wells and the diffusion region to thus identify the high and low threshold devices when the voltage on the selected word line is decreased. By eliminating the P+ regions and storing charge, e.g., electrons, at selected locations under the word lines in dual insulating layers, the cells may be electrically programmable.
摘要:
A self biased differential amplifier has a switching point accurately set according to a reference voltage. DC hysteresis is provided, by a circuit internal to the differential amplifier. The amplifier has an input circuit having first and second series connected transistors, wherein the beta ratio of these first and second transistors is changed by enabling an additional transistor of a hysteresis circuit according to an output state of the differential amplifier. When the output state is "high", the switching point is decreased in order that temporary small drops (due to noise or glitches) in the input signal are ignored. Conversely, when the output state is "low", the switching point is increased in order that temporary small increases in the input signal are ignored.
摘要:
A differential logic system is provided for a complete logic family which has a first switching circuit that produces a given output signal at a first output node and a second switching circuit that produces a second output signal which is the complement of that of the given output signal at a second output node. First and second clocked devices are connected from the first and second output nodes, respectively, to a voltage source, and first and second inverters are connected to the first and second output nodes, respectively. Additionally, a regenerative circuit may be connected between the first and second output nodes and the voltage source.