Signetics

Other

Precision Monolithics, Inc.

Werner H Hoeft

An analog to digital flash converter provides a multiple bit, parallel output arranged in more significant to less significant bits. The converter includes a voltage to current converter for providing an analog signal as an input current to a plurality of parallel converter stages. A reference signal input is independent of the analog signal input. Each of the converter stages receives the analog input current. Each stage has a comparator for comparing the analog input current with a dependent signal derived from the reference signal. The comparators are connected so that the dependent signal for each comparator is derived from the reference signal on the basis of outputs from each comparator of more significant bit stages. The dependent signal for each stage is derived by means of a switch in each stage connected to receive the output of the comparator in the next adjacent more significant bit converter stage, to control operation of the switch. The switch of each more significant stage is connected to supply the dependent signal of any next adjacent stage to the comparator of its stage and each less significant bit stage. The converter stages convert the analog input signal to digital output bits corresponding to the number of the stages from the converter simultaneously.

Analog to digital flash converter

A digital control amplifier is provided as a unitary monolithic device to control the transfer function of an analog signal in response to a digital control, such as from a digital computer. A current transfer cell is employed which uses an amplifier circuit having transistors of like polarity, and is capable of both attenuation and greater than unity amplification of an input analog signal. A digital-two-analog converter is integrated into the system and employs a series of current dividers which enables a common reference current to be used for each bit of the converter. A current reference circuit for the converter employs a band gap voltage regulator with a temperature compensation design that varies the control signal applied to the current transfer cell to compensate for temperature-induced variations in the output of the cell.

Digital controlled amplifier

A variable impedance circuit in which nonlinearities caused by the application of a signal are substantially reduced by the use of a feedback circuit for cancelling out the added input current due to the application of the input signal. By using a feedback circuit to obtain the desired improvement in linearity, the gain of the feedback loop can be tailored to obtain the necessary impedance range and output swing in a circuit capable of operating at relatively low power supply voltages.

Electrically variable impedance circuit with feedback compensation

A Class 'B' amplifier circuit in which Class 'B' conversion takes place in a converter portion of the circuit in combination with a differential amplifier input circuit, rather than in the output stage. The converter modulates the DC bias current supplied to the differential amplifier input circuit as a function of the input signal, in order to achieve Class 'B' operation. The output amplifier portion of the circuit includes a pair of complementary, series-connected transistors, each of which is connected in a common-emitter configuration. The disclosed circuit provides a high input impedance and excellent dynamic range.

Class 'B' type amplifier

A constant current source circuit includes a single differential amplifier having both voltage and temperature stabilization circuits. The voltage and temperature stabilization circuits operate on a feedback principle, each receiving an input from the differential amplifier, and each in turn providing a signal back to the differential amplifier to provide the desired stabilization. The resulting circuit is particularly adapted for use in battery-powered equipment, where substantial variations in both temperature and operating voltage are likely to occur.

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Saratoga, CA, United States of America

Werner H Hoeft