| Patent application number | Description | Published |
|---|
| 20080204292 | Output Architecture for LCD Panel Column Driver - In one embodiment consistent with the present invention, a digital to analog converter (DAC) circuit operates over an upper range and a lower range. An upper voltage node is designated AVDD; a middle voltage node is designated HVDD; and a lower voltage node designated ground. An upper DAC stage has at least one NMOS transistors that produces an output to an upper range output node when the output is in the upper range. A lower DAC stage has at least one PMOS transistors that produces an output to a lower range output node when the output is in the lower range. A body bias control circuit couples the body of the upper NMOS transistor to a voltage source equal to HVDD−Vbe and connects the body of the lower PMOS transistor to voltage source equal to HVDD+Vbe. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract. | 08-28-2008 |
| 20100157493 | ELECTROSTATIC DISCHARGE PROTECTION CIRCUIT - An integrated circuit includes an electrostatic discharge (ESD) detection circuit which detects an ESD event and generates an event signal. In response to that event signal, a control circuit controls the operation of a buffer circuit to function in an additional mode wherein the normal differential operation of the buffer circuit is disabled and the buffer circuit is instead configured to form a conduction path between supply rails to discharge the ESD event. Preferably, a plurality of buffer circuits are driven in parallel by the control circuit to function in the additional mode to form parallel discharge paths for the ESD event. Multiple ESD detection circuits may be provided, and any one of those detection circuits can trigger the control circuitry to place all of the buffer circuits in the additional mode. | 06-24-2010 |
| 20110242048 | CAPACITIVE SENSING ANALOG FRONT END - A capacitive sensing analog front end for a touchscreen system having an improved signal-to-noise ratio includes a capacitance-to-voltage converter having an input for coupling to an external sampling capacitor, a summer having a first input coupled to an output of the capacitance-to-voltage converter, a low pass filter having an input coupled to an output of the summer and an output for providing an output signal; and a sample-and-hold circuit having an input coupled to the output of the low pass filter and an output coupled to a second input of the summer. The signal-to-noise ratio of the touchscreen system is improved by extracting the DC shift of a touch signal during a monitoring period and then subtracting the DC shift before integrating the touch signal. | 10-06-2011 |
| 20120092201 | System and method for compact cyclic digital to analog converter - A system for implementing a cyclic digital to analog converter (c-DAC) is capable of supporting a large size liquid crystal display. The system includes an upper DAC stage configured to output a first voltage between a lower voltage supply (HVDD) and an upper voltage supply (AVDD). The system also includes a lower DAC stage configured to output a second voltage between the lower voltage supply (HVDD) and a ground. The upper DAC stage includes a single PMOS switch and the lower DAC stage includes a single NMOS switch. | 04-19-2012 |
| 20120112817 | METHOD AND APPARATUS FOR CAPACITANCE SENSING - A capacitance-to-digital converter for an extended range of capacitances includes a reference capacitor and one or more offset capacitors. Electrical charge accumulated in the offset capacitors is used to at least partially cancel the charge accumulated in a sensed capacitance to facilitate matching with a charge accumulated in the reference capacitor. The residual charge is passed to an integrator, the output from which is quantized and used to control switching of the capacitors. Immunity to tonal external noises and improved conversion speed are achieved by controlling the capacitor switching with a spread spectrum clock. The capacitance-to-digital converter may be used, for example, for sensing of the capacitances of capacitive elements in touch and proximity displays or other user interfaces. | 05-10-2012 |
