Xerox Corporation

Harry Jonathan McIntyre

Mostafa R Yazdy

Alan J Werner, Jr

Mehrdad Zomorrodi

Christopher L Chua

David Kirtland Fork

Ping Mei

Guillermo Lao

Francesco Lemmi

Mohamad M Mojaradi

JengPing Lu

Dale Sumida

Son Ngoc Nguyen

This is a PCBA that can be used in any system where one component or package is connected to another component or package. This invention provides a very short connector or signal path that avoids the necessity of a signal trace termination in the PCB. The PCB has on its upper surface a first component or package and on its lower surface a second component or package in vertical physical and signal alignment with the first component or package. The first component or package has a BGA on its bottom surface and the second component has a BGA on its top surface, both of these BGAs are in electrical contact with each other. Because of the short signal trace provided, the PCB provides signal transitions as fast as 200 pS.

Back-to-back package accomplishing short signal path lengths

Aspects of the disclosure provide methods and systems to design a distributed discrete capacitor bank incorporating power plane capacitance to concentrate the suppression of AC coupling to the frequencies caused by clocks and signal transitions. Aspects of the disclosure provide a procedure for designing a distributed capacitor bank from a combination of bulk capacitors, ceramic capacitors and/or plane capacitance that provides the desired impedance Z to suppress noise at all desired frequencies.

Sub-system power noise suppression design procedure

A driving circuit for a light emitting diode may include two transistors and an operational amplifier. The operational amplifier may act to cause the output voltages of the drain terminals of the transistors to be substantially equal, making the light emitting diode forward current substantially equal to the reference current. This current may provide a steady drive current, even when the supply voltage varies over a wide range.

Driving circuit for light emitting diode

A hybrid structure or device is provided wherein carried on a single substrate is at least one micro-spring interconnect having an elastic material that is initially fixed to a surface of the substrate, an anchor portion which is fixed to the substrate surface and a free portion. The spring contact is self-assembling in that as the free portion is released it moves out of the plane of the substrate. Also integrated on the substrate is a sensor having an active layer and contacts. The substrate and sensor may be formed of materials which are somewhat partially transparent to light at certain infrared wavelengths. The integrated sensor/spring contact configuration may be used in an imaging system to sense output from a light source which is used for image formation. The light source may be a laser array, LED array or other appropriate light source. The sensor is appropriately sized to sense all or some part of light from the light source. The sensor may also be sufficiently transparent so that light is not blocked from its emission path, with a contrast ratio such that it only absorbs a small fraction of light passing therethrough. An additional characteristic is that the manufacturing process is compatible with the manufacturing process for the micro-spring interconnects. Data from the sensor is used as light source correction information. This information is provided to a calibration configuration which allows for calibration of high-speed systems.

Amorphous silicon sensor with micro-spring interconnects for achieving high uniformity in integrated light-emitting sources

An operational amplifier circuit connected to a bi-directional cascode current amplifier is disclosed. The operational amplifier uses the bi-directional cascode current amplifier to filter out the common-mode signal resulting in a nearly infinite open loop gain without bandwidth degradation.

Opamp with infinite open loop gain

A light emitting diode driver is arranged to supply a drive current to a light emitting diode. The light emitting diode forms a radiant output and is arranged with a photo detector that forms a monitor signal based on the radiant output. The drive current comprises a first current and a second current. A comparison signal is formed by comparing the monitor signal and a level control signal. A buffered output signal is provided based on the comparison signal. The first current is provided based on the buffered output signal. A difference voltage is formed based on the first current. An amplified signal is provided based on the difference voltage. The second current is provided based on the amplified signal.

Light emitting diode driver and image forming device including the same

A differential amplifier circuit connected to an impedance transport circuit is disclosed. The impedance transport circuit transports an AC input impedance to an output impedance and invert its polarity thereby enabling the common-mode gain of the differential amplifier to be varied. This impedance transport circuit utilizes two MOS transistors and an Op-Amp that causes the drain voltages of the transistors to be equal.

Operational amplifier with common mode gain control using impedance transport

A laser driver uses a switch, a current mirror, a control transistor and two current generators to control the ON and bias currents in a laser diode. In the bias mode the current from one generator is shared by one half of the current mirror and the adjustable control transistor. The other current generator then drives the other half of the mirror circuit and the laser diode in parallel, resulting in the laser diode getting the same amount of current that the control transistor gets. In the ON mode, the switch cuts off the first half of the current mirror, which is mirrored in the other half, so that all of the other generator current is used in the laser diode. The current drivers are adjustable to the ON current and the control transistor current is adjustable to the bias current.

Current switching driver with controlled bias and ON states

An impedance transport circuit, which is capable of transporting both AC and DC impedance, utilizes two PMOS transistors and two n-channel transistors with two operational amplifiers. The two operational amplifies cause the drain voltages of all transistors to be equal and therefore transport both the AC and DC input impedance to the output impedance.

Impedance transport circuit

There is disclosed a shunt voltage regulator which utilizes a reference voltage which generates a floating output voltage with respect to a voltage to be regulated. The shunt voltage regulator of this invention also utilizes the voltage to be regulated as a power supply to its reference voltage generator, the level shifters and the Op-Amp.

Shunt voltage regulator utilizing a floating reference voltage

There is disclosed a converter for converting a floating voltage of a Band Gap Reference voltage generator fabricated in P-substrate CMOS technology to a fixed voltage with respect to ground. The converter of this invention utilizes a subtractor to convert the floating voltage to a fixed reference voltage. In addition, the converter of this invention utilizes two level shifters which are able to level shift the floating voltage down and level shift the shifted down voltage substantially back to the level of the floating voltage in order to allow a buffer to be used prior to the subtractor.

Design technique for converting a floating band-gap reference voltage to

An infrared reflectance densitometer (IRD) sensor which utilizes four blocks each of which generates an element of a given equation and a fifth block which generates an output voltage based on the given equation. The IRD sensor eliminates a problem known as hunting.

Xerographic infrared reflectance densitometer (IRD) sensor

A circuit which can be used to hold either the maximum or minimum voltage applied. A comparator compares the input voltage to the previous high or low and a set of two mirror circuits either charge or discharge a holding copacitor to the new value. A control circuit of transistor switches configures the circuit into either a maximum or minimum holding mode.

Maximum/minimum hold circuit

An electrostatic measurement apparatus for generating a modified electrical signal in proportion to an electrostatic potential present on a surface. The apparatus includes a sensor for producing a signal representative of the electrostatic potential on the surface. The apparatus also includes high-voltage and low-voltage devices combined to produce an amplifier which transforms the sensor signal into a low-voltage signal indicative the surface potential. The electrostatic measurement apparatus is implemented using high-voltage and low-voltage integrated circuit technology.

Electrostatic voltmeter employing high voltage integrated circuit devices

An operational amplifier comprises two amplifiers of like circuit configuration and complementary conductivity type connected in parallel. Each amplifier includes a folded cascode input section for providing a first stage of amplification, a class A, push-pull output section for providing a final stage of amplification, a bias section for providing bias voltages to the other sections, and a common made feedback (CMF) section. Each CMF section adjusts the output voltage of its associated input stage to the desired quiescent voltage to compensate for any process differences in the input section. To minimize quiescent power consumption, each CMF section and its associated input section are designed to set the quiescent output voltage of the input section to a level that biases the output transistors of the output section at their threshold voltages.

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Los Angeles, CA, United States of America

Harry Jonathan McIntyre