Centre Electronique Horloger S. A.

Other

Logitech, Inc.

Eric A Vittoz

Henri J Oguey

Marc A Bidiville

Jean Fellrath

Javier Arreguit

Jean Felix Perotto

Marc Degrauwe

Electronic function module for generating a current which any rational power of another current

A pointing device including a ball engaging one or more shaft encoders, each shaft encoder having an encoding wheel, including a monolithic photosensitive array for detecting light pulses representative of rotary movement of the ball. The photosensitive array provides a plurality of resolutions and permits accurate tracking of rotary movement of the ball without need for a mask. Comparator and latch means operate on the output of the array and provides digital hysteresis.

Pointing device with differential optomechanical sensing

The present invention relates to a reference voltage source in CMOS technology. The reference voltage source is based on the use of two compatible bipolar transistors (T1) and (T2) working at different current densities. A transresistance amplifier (1) connected as a negative feedback between the collectors and bases of (T1) and (T2) delivers the reference voltage (V.sub.ref). A conductor block (4) allows sufficient current to be drawn through the resistors (2) and (3) to render neglible the base current of (T1).

Reference voltage source

The invention concerns an amplifier comprising means for compensating for the input drift voltage. During a preparation phase, the input signal of the amplifier (10) is nullified by short-circuiting the inputs (12) and (13) by means of the change-over switch (30) and the output (15) is connected to a capacitor (40) and to a secondary input (14) of the amplifier. The secondary input has a substantially lower gain than the gain relative to the main input (13), which makes it possible substantially to reduce the effect of charge injection caused by opening of the switch (60). In the amplification phase, the input (13) receives an input signal (V1) and the input drift voltage (.alpha.V) is compensated by means of the value stored in the capacitor (40).

Amplifier with input drift voltage compensation

There is disclosed a differential amplifier which comprises bipolar transistors which may be produced using MOS technology and wherein the amplifier is particularly useful when the transistors have a poorly defined current gain. The amplifier includes a first pair of transistors having emitters connected in common and having bases forming the inputs to the differential amplifier. A second pair of transistors identical to the first pair are coupled such that the emitters and bases of said second pair are connected respectively to the emitters and bases of the first pair. The collectors of the second pair of transistors are connected to a current generator and to the input of a transconductance amplifier such that the transconductance amplifier causes the sum of the emitter currents of the first and second pairs of transistors to be controlled by the current supplied by the current generator.

Differential amplifier with bipolar transistors which is compatible with

A dynamic amplifier comprises two complementary MOS transistors T1 and T2 which are connected in series, the gates G1 and G2 of which are connected to each other and to an input node by way of capacitors C1 and C2. The gate of T1 is connected to its drain by a switch means S1. The input node is connected to an input terminal and a reference voltage terminal by switch means S4 and S3 respectively and an output node between T1 and T2 is connected to an output terminal by switch means S5. The gate of T2 is connected by way of a switch means S2 to a bias voltage source. The switch means S1 to S5 are actuated in such a way that in a first, preparation phase of the amplifier, switches S1, S2 and S3 are closed with the input node being at a reference voltage Vref and the currents I1 and I2 through T1 and T2 being equal to a value fixed by the voltage source and, in an amplification phase, switches S4 and S5 are closed so that the output current Is increases in absolute value with the voltage Ve applied to the input node.

CMOS Dynamic amplifier

An integrated control device for controlling a device such as a LED display or a miniature stepping motor for an electronic watch comprises at least one insulated-gate field effect transistor for controlling the supply of current to the element. The gate of the F.E.T. is connected to a control circuit including a voltage multiplier comprising a series-connected chain of rectifiers and a plurality of capacitors connected between the respective junctions between rectifiers and alternate inputs. High frequency signals of opposite phase are supplied to the inputs under control of an input control signal. Circuit means are provided for starting the action of the voltage multiplier at the beginning of an input control signal and for short-circuiting the output of the control circuit at the end of an input control signal.

Integrated insulated-gate field-effect transistor control device

The invention relates to logic CMOS transistor circuits formed by at least one gate circuit, each gate circuit comprising a pair of CMOS transistor groups connected in series between the terminals of a power supply. The conductive state of both groups of transistors defines the potential of a common connection point or output node. A power dissipating means of relatively high resistance is coupled in parallel with at least a part of at least one of the said transistor groups, at least during a time interval in which both groups are in a non conductive state. This results in a quasi static behavior of the circuits according to the invention although the basic structure of the same is that of dynamic circuits.

Logic CMOS transistor circuits

A binary frequency divider circuit with insulated gate field effect transistors (MOST) powered by a constant voltage source is derived from a known static circuit by eliminating transistors that do not take part in switching, which allows nodes of the circuit to float. Certain transistors, which are eliminated in known dynamic circuits, are retained so that the nodes float for only one value of an input variable, but not for the other.

Binary frequency divider

A multifunctional wrist watch combining the functions of time-indication with other functions, for example a calculator. The watch has a glass in which pick-ups are provided for detecting the passage of a finger of a user over the surface of the glass and recognition circuits for converting the trace detected into a logic signal for processing by a calculator circuit provided in the watch case. The output of the calculator is then displayed by the electro-optical display on the watch. The detection and recognition facility may also be utilized for correction of the date and time settings of the watch.

Multi-functional electronic watch

An autonomous electric watch comprises a receiver for picking up a magnetic or acoustic coded regulation signal delivered by a telephone set, and a control circuit automatically controlling memory circuits of the watch to regulate the frequency and/or set the time displayed in response to reception of such a signal. The regulation signal is provided by a signal generator connected to an automatic telephone reply apparatus that can be called from any subscriber telephone set, and may be combined with a pre-recorded spoken message giving instructions to the caller.

Automatic regulation of an electronic watch

CMOS oscillator in which the oscillator circuit comprises a first MOS transistor connected by its source to a first terminal of a voltage supply and biased by the current provided by a second MOS transistor of opposed type which is a part of the same integrated circuit. At least a third MOS transistor (T.sub.6, T.sub.8, T.sub.12) of the same type as the second and which is a part of the same integrated circuit is provided, the sources and gates of the second and third transistors being respectively connected together and respectively to the second terminal of the voltage supply and to a point (P) at a potential such that the mean drain current of the first transistor will be maintained at a value just higher than the value at which oscillation starts.

CMOS oscillator with first and second MOS transistors of opposed type

A device for providing an electro-optical display of time comprises an electronic timekeeper fed by a voltage source and including a time base and a frequency divider. An electro-optical display is formed of groups of electro-chromic cells each able to take two different visual aspects. The cells are controlled by a code converter supplying state variables corresponding to the desired aspects of the cells to provide a display of time. One aspect of the cells corresponds to a stable state, the other aspect to a quasi-stable state which in order to be maintained, requires very low or zero power. Transition of a cell from one state to another requires precisely determined amounts of energy. A change detector supplies to a selector, data to actuate the operations of inscription and erasure of the display cells. The selector dispenses the required amounts of energy supplied to the display to ensure correspondence between the state variables delivered by the code converter and the aspect of the corresponding display cells, in a manner ensuring transition from one state to another with a minimum supply of energy.

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Cernier, Switzerland

Eric A Vittoz