Abstract: A combined touch sensor and light-emitting-diode (LED) driver comprises a touch sensor circuit configured to detect a touch, where the touch sensor circuit is coupled to a common node and configured to operate with a first operating voltage, an LED driver circuit configured to drive an LED if the LED is coupled to the common node, where the LED driver circuit is also coupled to the common node and configured to operate with a second operating voltage is higher than the first operating voltage, and an n-type field effect transistor (FET) connected in series between the common node and the touch sensor. The n-type FET prevents the higher operating voltage of the LED driver from affecting the operation of the touch sensor, when a port of the combined touch sensor and LED driver IC is used to drive an LED. The touch sensor may be a capacitance-to-digital converter.

Abstract: The scanned channel and the non-scanned channels of a capacitive touch sensor are driven by a scan signal and a shield signal, respectively, with the shield signal having a substantially same amplitude and a substantially same phase as the amplitude and the phase, respectively, of the scan signal. Thus, the potentials at both the routing line of the scanned channel and the routing line of the non-scanned channels follow each other and are maintained substantially same regardless of which channel is the scanned one. As a result, the parasitic capacitance arising between the two routing lines is reduced significantly, and the accuracy and the sensitivity of the touch sensor are significantly enhanced.

Abstract: A key is determined to be the user-selected key of a touch sensitive input device if the touch on the key is determined to be valid continuously for longer than a first predetermined period of time. Another key may be determined to the user-selected key, replacing the previously determined user-selected key, if the touch on another key is valid continuously for a second predetermined period of time that may be longer than the first predetermined period of time.

Abstract: A combined touch sensor and light-emitting-diode (LED) driver comprises a touch sensor circuit configured to detect a touch, where the touch sensor circuit is coupled to a common node and configured to operate with a first operating voltage, an LED driver circuit configured to drive an LED if the LED is coupled to the common node, where the LED driver circuit is also coupled to the common node and configured to operate with a second operating voltage is higher than the first operating voltage, and an n-type field effect transistor (FET) connected in series between the common node and the touch sensor. The n-type FET prevents the higher operating voltage of the LED driver from affecting the operation of the touch sensor, when a port of the combined touch sensor and LED driver IC is used to drive an LED. The touch sensor may be a capacitance-to-digital converter.

Abstract: A scheme to reduce output variations in a column driver for a flat-panel display by sharing the characteristics of analog circuit is disclosed. An input multiplexer is provided between two neighboring digital inputs, and an output multiplexer is provided between two neighboring analog outputs so that the characteristics of neighboring analog circuits can be shared by multiplexing. The averaging effect by sharing reduces variations in the output. The multiplexing may be done either in time division or on a frame-by-frame basis.

Abstract: A scheme to reduce output variations in a column driver for a flat-panel display by sharing the characteristics of analog circuit is disclosed. An input multiplexer is provided between two neighboring digital inputs, and an output multiplexer is provided between two neighboring analog outputs so that the characteristics of neighboring analog circuits can be shared by multiplexing. The averaging effect by sharing reduces variations in the output. The multiplexing may be done either in time division or on a frame-by-frame basis.