Abstract: A comparator having first and second stages can provide component offset compensation and improved dynamic range. The first stage can receive first and second input signals and produce first and second output signals. The second stage can be coupled to the first stage to receive the first and second output signals at first and second input terminals of the second stage. The second stage can provide a voltage to the first and second terminals that differs from the supply voltage by less than a voltage of a diode drop. The comparator is operable to receive input voltages that reach the supply voltage.

Abstract: A short circuit detection module for a touch panel includes first and second short circuit detection circuits. The first short circuit detection circuit is coupled to a first conductive line of the touch panel. The first short circuit detection circuit is configured to drive the first conductive line with a first signal having a first logic level. The second short circuit detection circuit is coupled to second, adjacent, conductive line of the touch panel. The second short circuit detection circuit is configured to drive the second conductive line with a second signal having a second logic level that is complementary to the first logic level.

Abstract: An analog switch includes a transistor whose source connected to a signal input and whose drain is connected to a signal output. An output of a gate control circuit is connected to the transistor gate. A first input of the gate control circuit is connected to the source of the transistor. The gate control circuit responds to a logic transition of an enable signal received at a second input by pre-charging a substantially constant gate-to-source voltage across the transistor. This voltage is stored by a gate-to-source connected capacitor. In one steady-state logic condition of the enable signal, the gate control circuit operates to turn off the transistor. In another steady-state logic condition of the enable signal, the gate control circuit permits the signal received at the signal input to drive the gate of the transistor with a voltage offset by the substantially constant gate-to-source voltage stored on the capacitor.

Abstract: 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.

Abstract: In one embodiment, a semiconductor circuit for coupling a first node to a second node includes a first transistor having a first terminal coupled to the first node, a second terminal coupled to the second node, and a control terminal coupled to a control node. The circuit also includes a level shifting circuit having a series diode for coupling a bulk terminal of the first transistor to the control node, and a supply coupling circuit coupled between a first power supply node and the control node.

Abstract: An analog switch configuration includes a gate control circuit coupled between an input of a switch and a gate of the switch. The gate control circuit passes voltage changes on the input of the switch to the gate of the switch to decrease the influence the inherent gate to input capacitance has on the bandwidth of the switch. By reducing the change in voltage across the inherent capacitance, the current through the capacitance in decreased as well as its influence on the bandwidth of the configuration.

Abstract: In one embodiment, a semiconductor circuit for coupling a first node to a second node includes a first transistor having a first terminal coupled to the first node, a second terminal coupled to the second node, and a control terminal coupled to a control node. The circuit also includes a level shifting circuit having a series diode for coupling a bulk terminal of the first transistor to the control node, and a supply coupling circuit coupled between a first power supply node and the control node.

Abstract: An analog switch includes a transistor whose source connected to a signal input and whose drain is connected to a signal output. An output of a gate control circuit is connected to the transistor gate. A first input of the gate control circuit is connected to the source of the transistor. The gate control circuit responds to a logic transition of an enable signal received at a second input by pre-charging a substantially constant gate-to-source voltage across the transistor. This voltage is stored by a gate-to-source connected capacitor. In one steady-state logic condition of the enable signal, the gate control circuit operates to turn off the transistor. In another steady-state logic condition of the enable signal, the gate control circuit permits the signal received at the signal input to drive the gate of the transistor with a voltage offset by the substantially constant gate-to-source voltage stored on the capacitor.

Abstract: A transmission gate includes first and second MOS transistors of opposite conductivity type coupled in parallel with each other. Each transistor includes a body connection that is separately biased by corresponding first and second biasing circuits. The first biasing circuit generates a first bias voltage having a voltage level that is generated as a function of the signal at the first node and a first (for example, positive) reference voltage. The second biasing circuit generates a second bias voltage having a voltage level that is generated as a function of the signal at the first node and a second (for examples ground) reference voltage.

Abstract: An analog switch includes a transistor having a current path between an input and an output, a gate coupled to a control terminal, and a bulk terminal, and a switched bulk control circuit coupled to the control terminal, the bulk terminal, and ground to reduce an equivalent capacitance seen from a source terminal or drain terminal of the transistor towards the bulk terminal of the transistor. The bulk control circuit includes an all-NMOS bulk control circuit if an NMOS transistor switch is used.

Abstract: A transmission gate includes first and second MOS transistors of opposite conductivity type coupled in parallel with each other. Each transistor includes a body connection that is separately biased by corresponding first and second biasing circuits. The first biasing circuit generates a first bias voltage having a voltage level that is generated as a function of the signal at the first node and a first (for example, positive) reference voltage. The second biasing circuit generates a second bias voltage having a voltage level that is generated as a function of the signal at the first node and a second (for examples ground) reference voltage.