Abstract: A circuit that automatically, seamlessly connects the higher (or the lower) of two power supplies to an output is described. The circuit does not incur a one diode drop when the two power supplies are at about the same voltage levels, and the unused power supply draws no stand-by current. Cross coupled transistor and cross coupled inverters are employed.

Abstract: A circuit that automatically, seamlessly connects the higher (or the lower) of two power supplies to an output is described. The circuit does not incur a one diode drop when the two power supplies are at about the same voltage levels, and the unused power supply draws no stand-by current. Cross coupled transistor and cross coupled inverters are employed.

Abstract: A MOSFET switch is disclosed that is driven on by a circuit that provides a constant gate to source voltage, Vgs, that is independent of the input voltage, the power supply and any logic signals. The constant Vgs is derived from a reference voltage and biases the MOSFET switch such that Ron is constant, or Rflatness is minimized. A minimized Rflatness provides a higher fidelity transfer of audio signals compared to prior art switches where Rflatness is greater.

Abstract: A circuit is described that when the power supply to circuits that control a pass transistor is at zero volts, the pass transistor configured as a voltage level translator remains off regardless of the voltages and changes in voltages at the ports connected to the pass transistor. Cross coupled transistors provide a mechanism where the higher of the port voltages is available to power circuitry that maintains the control input of the pass transistor in the off condition. The voltages at the ports may rise and fall relative to each other, but the control input of the pass transistor will keep the pass transistor off.

Abstract: A MOSFET switch is disclosed that is driven on by a circuit that provides a constant gate to source voltage, Vgs, that is independent of the input voltage, the power supply and any logic signals. The constant Vgs is derived from a reference voltage and biases the MOSFET switch such that Ron is constant, or Rflatness is minimized. A minimized Rflatness provides a higher fidelity transfer of audio signals compared to prior art switches where Rflatness is greater.

Abstract: A circuit is described that when the power supply to circuits that control a pass transistor is at zero volts, the pass transistor configured as a voltage level translator remains off regardless of the voltages and changes in voltages at the ports connected to the pass transistor. Cross coupled transistors provide a mechanism where the higher of the port voltages is available to power circuitry that maintains the control input of the pass transistor in the off condition. The voltages at the ports may rise and fall relative to each other, but the control input of the pass transistor will keep the pass transistor off.

Abstract: A serializing/deserializing interface is discussed for reducing the number of connections and signals being carried over a flex cable as would be found in a hand held mobile device. In particular the interface interleaves data, multiplexes data and multiplexes control for a number of I/O devices. For example those I/O devices might include an LCD display, a camera, a keypad and a GPIO (general purpose I/O) device.

Abstract: A serializer is described that incorporates a register and a delay circuit for each serial bit. The serializer provides a timing signal that is generated and output simultaneously with the output of the data bit that ensures close timing alignment of the data bit and the timing signal. No clock is used. This allows the deserialzer/receiver to reliably receive the data bit. Each illustrative delay circuit is configured to trigger the next register/delay circuit to output the next sequential bit and its timing signal.

Abstract: An enveloping curves generator is disclosed that guarantees that one curve will envelop or overlap another when both are traversing from one logic level to another, and where the other overlaps the first when both traversing the other direction. In one case, a steering FET controlled by an input signal drives a first output high via a circuit. That first output going high, after a delay, drives a second output high. When the input goes low, a second steering FET controlled by the input signal drives the second output low. That second output going low, after a delay, drives the first output low. No latching is provided in the present invention.

Abstract: In a circuit and method for adjusting rise-and-fall-time changes in an output driver signal due to changes in temperature, process or voltage, the driver output voltage is monitored and current flow through a constant load resistor adjusted as the voltage changes. The current may be adjusted by controlling the gate-source voltage on a transistor. The gate voltage on the transistor may also be used to adjust the power supply to pre-drivers of the output driver.

Abstract: An output buffer circuit includes a pull-up output transistor formed in a well, the well isolated from the power supply only when a voltage exceeding the power supply voltage appears on the buffer output node. Isolation of the well is accomplished by linking the well to the power supply through an isolation transistor, such that the control node of the isolation transistor receives the output of a switching inverter utilizing the buffer output voltage as its high power rail. During normal operation, the output voltage is less than the power supply voltage and thus the output of the switching inverter is low. As a result, the isolation transistor is activated, and the well is pulled up to the power supply voltage. Appearance of a voltage greater than the circuit power supply on the buffer output node activates the switching inverter, raising the control voltage and deactivating the isolation transistor. In this manner, the well is isolated from the power supply rail.