Stmicroelectronics Asia Pacific Pte Limited

Stmicroelectronics S.r.l.

Stmicroelectronics Asia Pacific Pte Ltd (sg)

Dianbo Guo

Kien Beng Tan

Yannick Guedon

Chee Weng Cheong

Leonard Liviu Dinu

Sze-Kwang Tan

Chaochao Zhang

Ernesto Lasalandra

Paolo Angelini

Praveesh Chandran

Tommaso Ungaretti

Giovanni Carlo Tripoli

Giuseppe Noviello

Baranidharan Karuppusamy

Kusuma Adi Ningrat

Eng Jye Ng

EngJye Ng

CheeWeng Cheong

Lokesh Kumar Korapati

Abhishek Singh

Chao Chao Zhang

Leonard Dinu

KienBeng Tan

Anthony Junior Casillan

A capacitive discharge circuit includes a line having a capacitance, a switched capacitor circuit including a capacitor, a switched circuit coupled to the line, and a voltage regulator coupled between the switched capacitor circuit and the switched circuit. A controller operates the switched capacitor circuit and switched circuit to in a first phase, charge the capacitor by coupling the capacitor between a common mode and a power supply, and in a second phase, discharge the capacitor by coupling the voltage regulator in series with the capacitor between the power supply node a ground. The controller is also configured to in a third phase, charge the capacitor by coupling the capacitor between the common mode and the power supply, and in a fourth phase, share charge between the line and the capacitor by coupling the voltage regulator and the capacitor in series between the line and the ground.

Capacitive discharge circuit for touch sensitive screen

A system and method for synchronizing two devices in communication with each other. When communication between the two devices is to be established, a synchronization process may be invoked. In an embodiment, a first device may initiate sending synchronization signals having rising edge and falling edge pairs. The second device may include a controller configured to receive the synchronization signals. However, noise may inhibit the ability of the controller to correctly receive and/or interpret the synchronization signals. Noise may cause detection components to falsely detect noise as a synchronization signal or may cause detection components to miss detection of an actual synchronization signal. A window generator may be used to generate comparison windows for the controller to detect synchronization signals. Further, the detection window duration and start times may be adjusted based on previously detected (or undetected) synchronization signals in order to compensate for noise overshadowing synchronization signals.

System and method for improved synchronization between devices

A readout device for a capacitive sense matrix includes a computer readable storage medium configured to store capacitance data. The capacitance data represents capacitance values of the capacitive sense matrix. The readout device also includes a readout circuit configured to receive a signal from the capacitive sense matrix, the readout circuit being configured based upon the capacitance data. Also described are a readout method and a method of compensating for variations in capacitance.

Compensation for variations in a capacitive sense matrix

An active stylus is capacitively coupled to a capacitive touch panel for communication. The active stylus operates in a wait mode to receive initial communications from the panel. In response to such receipt, the active stylus synchronizes to a repeating communications frame implementing time division multiplexing. Communications from the active stylus to the panel include: information communications; synchronization communications and communications specific for columns and/or rows of the panel. Communications from the panel to the active stylus may be addressed uniquely to the stylus or commonly to a group of styluses.

System and method of communication between a capacitive touch screen and an active stylus

A charge sensing circuit generates a voltage in a sensing period that is indicative of sensed charge. The generated voltages are accumulated by an accumulator circuit over a number of sensing periods. A noise detection circuit senses when the voltage generated by the charge sensing circuit is outside of a boundary and generates a detection signal in response thereto. A control circuit, in response to the detection signal, controls the accumulator circuit to block accumulation of the voltages generated by the charge sensing circuit during at least the sensing period in which the detection signal is generated. An analog-to-digital converter circuit then converts an accumulated output voltage from the accumulator circuit to a digital value at the end of an accumulation time period that includes the sensing periods. The end of the accumulation time period is delayed by at least one sensing period in response to the detection signal.

Method and apparatus for blocking accumulation of electrical fast transient (EFT) noise

A master-slave circuit is disclosed that maintains synchronization between two integrated circuit chips, using minimal chip resources. In one embodiment, a single, bidirectional communication path is shared by the two chips. Meanwhile, only one I/O port on each chip is used to send and receive signals via the bidirectional communication path. The first chip to detect a signal event is designated the master and controls the bidirectional communication path. The master can communicate the status to the other chip by controlling the logic state of the I/O ports. When the second chip detects that the I/O port is controlled by the first chip, the second chip will logically deduce that it is now the slave. If both chips detect the signal event at substantially the same time, one of the two chips is pre-programmed to assume control of the I/O port as the master.

Chip synchronization by a master-slave circuit

A microelectronic short circuit detection module is disclosed that locates and distinguishes among different types of short circuits in touch screen panels. Individual short circuit detection circuits are coupled to force and sense lines throughout a wire matrix within the touch screen. If the line is shorted to a neighboring line or any other line carrying an opposite logic state, its logic state will be corrupted by the short and will be held at a value opposite that of the intended input signal. Comparing the input and the output therefore provides an indicator of a short circuit to another force or sense line in the wire matrix. A pair of pull up/down stages is engaged to detect whether the short is coupled to power or ground. A threshold resistor can be varied to adjust detection sensitivity. By conducting a serial test, matrix coordinates of the short circuit can be identified.

Short circuit detection module

A touch screen device having a touch screen panel and a method for operating a touch screen device are provided. The method includes monitoring, during a noise monitoring phase, channel signals of a first set of channels and a second set of channel of the touch screen panel, detecting a stylus signal in response to a channel signal greater than a stylus threshold and less than a palm threshold, selecting the first set of channels when the stylus signal is detected on at least one channel of the first set of channels and is not detected on the second set of channels, and selecting the second set of channels when the stylus signal is detected on at least one channel of the second set of channels and is not detected on the first set of channels.

Touch screen with palm rejection in the presence of charger noise

Growing community of inventors

Singapore, Singapore

Dianbo Guo