Abstract: A method includes configuring a transmitter to provide at least three output levels used to form an output signal. The method further includes adjusting a duration of at least one of the output levels to control an average value of the output signal independently of an amplitude of a first harmonic of the output signal.

Abstract: An illustrative controller embodiment includes: a transmitter that causes reverberation of a piezoelectric transducer; and a linear damping module that measures characteristics of the reverberation and tunes at least one of a shunt resistance and a shunt reactance for the piezoelectric transducer based on said characteristics. An illustrative sensor embodiment includes: a piezoelectric transducer; and a transducer controller coupled to the piezoelectric transducer to transmit pulses and receive echoes for measuring distances. The controller includes a linear damping module with: a shunt resistance; a shunt inductance; and an optional switch that couples the shunt resistance and shunt inductance in parallel to the piezoelectric transducer to damp reverberation of the piezoelectric transducer after said transmit pulses. The controller measures at least one characteristic of said reverberation and responsively tunes the shunt resistance or the shunt inductance.

Abstract: A system for open circuit detection for inductive sensors includes coils coupled in a star configuration on a first side of each coil. The system further includes driving pins coupled to the coils on a second side of each coil and voltage sources coupled to the driving pins. The system further includes one or more comparators coupled to the driving pins that monitor the voltages of the driving pins to detect open circuits.

Abstract: A system for open circuit detection for inductive sensors includes coils coupled in a star configuration on a first side of each coil. The system further includes driving pins coupled to the coils on a second side of each coil and voltage sources coupled to the driving pins. The system further includes one or more comparators coupled to the driving pins that monitor the voltages of the driving pins to detect open circuits.

Abstract: In an embodiment, an LED controller is configured to form a charge transfer sequence to selectively enable LED transistors of a plurality of LED transistors that are configured for coupling in parallel with a plurality of LEDs. An embodiment may include that the LED controller is configured to sequentially couple a charge capacitor to a gate-to-source capacitor of each LED transistor of the plurality of LED transistors to one of charge or to refresh the gate-to-source capacitor of a respective LED transistor and to one of enable or re-enable the respective LED transistor wherein the gate-to-source capacitor is a parasitic gate-to-source capacitor of the LED transistor wherein the charge capacitor is sequentially coupled to the gate-to-source capacitor of each LED transistor.

Abstract: In an embodiment, an LED controller is configured to form a charge transfer sequence to selectively enable LED transistors of a plurality of LED transistors that are configured for coupling in parallel with a plurality of LEDs. An embodiment may include that the LED controller is configured to sequentially couple a charge capacitor to a gate-to-source capacitor of each LED transistor of the plurality of LED transistors to one of charge or to refresh the gate-to-source capacitor of a respective LED transistor and to one of enable or re-enable the respective LED transistor wherein the gate-to-source capacitor is a parasitic gate-to-source capacitor of the LED transistor wherein the charge capacitor is sequentially coupled to the gate-to-source capacitor of each LED transistor.

Abstract: In one embodiment, an LED current controller is formed to determine which of a plurality of LED branches has the largest voltage drop and to select the current through that branch to use in controlling the value of current that flows through other LED branches.

Abstract: In an embodiment a semiconductor device correlates a received signal with a known pattern. A correlation output is used as a basis for forming a confidence reference level. The confidence reference level and the correlation output are compared to identify a peak in the received signal indicating that a present signal state of the received signal contains the known pattern.

Abstract: In one embodiment, an LED current controller is formed to determine which of a plurality of LED branches has the largest voltage drop and to select the current through that branch to use in controlling the value of current that flows through other LED branches.

Abstract: In one embodiment, an acoustic distance measurement system can dynamically adjust its measurement frequency to a frequency that is within a preselected bandwidth of the resonant frequency of an acoustic transducer used in making acoustic distance measurements.

Abstract: In an embodiment a circuit provides an active resistance that is adjusted with temperature, the active resistance has a magnitude and temperature coefficient that is selected by the values of external resistors. The active resistance is controlled by an active resistance controller that uses a temperature dependent source and a temperature stable source to control adjustment of a first adjustable resistance to maintain correspondence between a temperature dependent parameter and a temperature stable parameter, and adjusts a second adjustable resistance that is part of the active resistance in correspondence with adjustment of the first adjustable resistance.

Abstract: In an embodiment a circuit provides an active resistance that is adjusted with temperature, the active resistance has a magnitude and temperature coefficient that is selected by the values of external resistors. The active resistance is controlled by an active resistance controller that uses a temperature dependent source and a temperature stable source to control adjustment of a first adjustable resistance to maintain correspondence between a temperature dependent parameter and a temperature stable parameter, and adjusts a second adjustable resistance that is part of the active resistance in correspondence with adjustment of the first adjustable resistance.

Abstract: In one embodiment, an acoustic distance measurement system can use a modulation pattern to modulate a carrier wave. The modulated carrier wave may be transmitted to an acoustic transducer. An echo of the transmitted signal can be detected by correlating the received signal with the modulation pattern. Subsequent to detecting sufficient correlation between the received signal and modulation pattern, a distance determination can be made to determine the distance to the object that produced the received echo.

Abstract: In an embodiment a semiconductor device correlates a received signal with a known pattern. A correlation output is used as a basis for forming a confidence reference level. The confidence reference level and the correlation output are compared to identify a peak in the received signal indicating that a present signal state of the received signal contains the known pattern.

Abstract: In one embodiment, a closed loop control system is caused to operate in an open loop configuration. At some time while operating in the open loop configuration the system detected the presence or absence of a.c. signals in an output signal of the system in order to detect the presence or absence of a failure of a control loop element, such as an output capacitor.

Abstract: A protection circuit for protecting an electronic circuit against EMC disturbances and/or negative transient overvoltage pulses comprises a switch in series between a power supply and the electronic circuit to be protected; a comparator for comparing a first operating parameter with a second operating parameter and producing a comparison signal, the comparison signal being used as a control signal for controlling opening and closing of the switch; and a delay circuit adapted for delaying closing of the switch. A corresponding method is also provided.

Abstract: An output driver circuit has an input, an output node, and first and second transistors coupled in series between the output node and a first source of operating potential. Parasitic diodes of the first and second transistors are anti-serially coupled. The output driver circuit has first and second control circuits coupled to control the first and second transistors respectively. The first transistor is controlled as a controlled current source depending on a signal at the input during normal conditions when the current that flows through the output is in a first direction, and the second control circuit controls the second transistor to prevent unwanted DC current at the output from flowing through the output in a second direction. The first and second transistors are also controlled to limit unwanted transient currents during an EMC disturbance substantially symmetrically.

Abstract: In one embodiment, an acoustic distance measurement system can use a modulation pattern to modulate a carrier wave. The modulated carrier wave may be transmitted to an acoustic transducer. An echo of the transmitted signal can be detected by correlating the received signal with the modulation pattern. Subsequent to detecting sufficient correlation between the received signal and modulation pattern, a distance determination can be made to determine the distance to the object that produced the received echo.

Abstract: In one embodiment, an acoustic distance measurement system can dynamically adjust its measurement frequency to a frequency that is within a preselected bandwidth of the resonant frequency of an acoustic transducer used in making acoustic distance measurements.

Abstract: In one embodiment, a closed loop control system is caused to operate in an open loop configuration. At some time while operating in the open loop configuration the system detected the presence or absence of a.c. signals in an output signal of the system in order to detect the presence or absence of a failure of a control loop element, such as an output capacitor.