Abstract: A remote keyless entry (RKE) transponder has a programmable selective wake-up filter for determining whether the RKE transponder should wake-up to process a received signal. The wake-up filter correlates the timing of an input signal's carrier amplitude on and off time periods to a predefined programmable time period profile for a desired signal which has a certain carrier on time (time period on) and a certain carrier off time (time period off) arranged into a coded “header.” When a received signal matches the predefined time period profile, then the RKE transponder will wake-up to process the incoming signal data. The predefined time period profile may be programmable and may be stored in a header configuration register. Each RKE transponder has unique predefined time period on and time period off profiles.

Abstract: Calibration of gain and/or offset of an instrumentation amplifier (INA) is accomplished by coupling an appropriate number of current sources, and/or current sinks, respectively, to first and/or second transconductance stage(s) of the INA. Gain and/or offset calibration of the INA may occur when requested by a user and/or the occurrence of an event(s). A voltage reference may be used in combination with a successive approximation register analog-to-digital converter in determining which ones of the current sources and sinks are coupled to the first and/or second transconductance stage(s) of the INA for gain and/or offset calibration thereof. After the gain and/or offset calibration of the INA is completed, the selection of the constant current sources and sinks used therefore may be stored in volatile or nonvolatile memory. Parity checking of the memory may be incorporated and if a parity error is detected, an auto-calibration of the INA may be initiated.

Abstract: Calibration of gain and/or offset of an instrumentation amplifier (INA) is accomplished by coupling an appropriate number of current sources, and/or current sinks, respectively, to first and/or second transconductance stage(s) of the INA. Gain and/or offset calibration of the INA may occur when requested by a user and/or the occurrence of an event(s). A voltage reference may be used in combination with a successive approximation register analog-to-digital converter in determining which ones of the current sources and sinks are coupled to the first and/or second transconductance stage(s) of the INA for gain and/or offset calibration thereof. After the gain and/or offset calibration of the INA is completed, the selection of the constant current sources and sinks used therefore may be stored in volatile or nonvolatile memory. Parity checking of the memory may be incorporated and if a parity error is detected, an auto-calibration of the INA may be initiated.

Abstract: Auto-calibration of the analog circuits occurs when requested by a user and/or the occurrence of an event(s). The user may invoke an auto-calibration on demand through an auto-calibration (ACAL) input to the mixed-signal integrated circuit. An external voltage calibration (VCAL) input may be used for auto-calibration of the mixed-signal integrated circuit to a user-supplied common-mode voltage reference. Auto-calibration of the mixed-signal integrated circuit may also be initiated upon the occurrence of any one or more of the following events: 1) detection of auto-calibration data corruption, e.g., parity checking of auto-calibration data values digitally stored in the mixed-signal integrated circuit; 2) an internal timer that causes a calibration request after a programmable timeout period, 3) change in the internal integrated circuit die temperature as determined by a temperature sensor, and 4) a change in the power supply and/or internal supply voltage(s).

Abstract: Auto-calibration of the analog circuits occurs when requested by a user and/or the occurrence of an event(s). The user may invoke an auto-calibration on demand through an auto-calibration (ACAL) input to the mixed-signal integrated circuit. An external voltage calibration (VCAL) input may be used for auto-calibration of the mixed-signal integrated circuit to a user-supplied common-mode voltage reference. Auto-calibration of the mixed-signal integrated circuit may also be initiated upon the occurrence of any one or more of the following events: 1) detection of auto-calibration data corruption, e.g., parity checking of auto-calibration data values digitally stored in the mixed-signal integrated circuit; 2) an internal timer that causes a calibration request after a programmable timeout period, 3) change in the internal integrated circuit die temperature as determined by a temperature sensor, and 4) a change in the power supply and/or internal supply voltage(s).

Abstract: A remote keyless entry (RKE) transponder has a programmable selective wake-up filter for determining whether the RKE transponder should wake-up to process a received signal. The wake-up filter correlates the timing of an input signal's carrier amplitude on and off time periods to a predefined programmable time period profile for a desired signal which has a certain carrier on time (time period on) and a certain carrier off time (time period off) arranged into a coded “header.” When a received signal matches the predefined time period profile, then the RKE transponder will wake-up to process the incoming signal data. The predefined time period profile may be programmable and may be stored in a header configuration register. Each RKE transponder has unique predefined time period on and time period off profiles.

Abstract: A multi-channel remote keyless entry (RKE) transponder having dynamically re-configurable input channel selection, channel disable, settable sensitivity for each channel, wake-up filter timing parameters, automatic gain control hold, internal tuning capacitor selection for each channel's antenna, minimum modulation depth requirement for input signal and bi-directional talk-back. Programmable minimum modulation depth requirement reduces false wake-up of the RKE transponder. An antenna for each channel of the RKE transponder may be tuned with internal tuning capacitors for improved range and receiver sensitivity. The internal tuning capacitor parameters may be stored in a configuration register. Gain of the channel may be fixed while the antenna is tuned. The antennas may be de-queued for talk-back to a base station for low frequency bi-directional communications. An external control device may dynamically read from and write to the configuration registers via a serial communications interface.

Abstract: An amplifier having programmable operational characteristics and a serial communications interface is fabricated on an integrated circuit (IC). The serial communications interface controls the operational characteristics, e.g., gain, frequency response, etc., of the amplifier. A multiplexer (MUX) may also be included on the IC and may be controlled by the serial communications interface. Status of the amplifier may also be obtained through the serial communications interface. The pin count of the IC package may be kept to a minimum by using the serial communications interface.

Abstract: Two nulling amplifiers are used with an auto-zeroed differential amplifier. While one nulling amplifier is compensating the main amplifier, the other nulling amplifier is being zeroed for both differential mode (DM) and common mode (CM) offsets. By using two nulling amplifiers, one always connected to the main amplifier, a relatively constant open-loop gain is maintained for the main amplifier. A further improvement is make-before-break timing overlap of the switch operations between the two nulling amplifiers and the main amplifier. This ensures that the main amplifier is continuously driven by one or both null amplifiers, thereby maintaining a low impedance at the main amplifier auxiliary port. Both DM and CM offset sampling and precharging of each of the two nulling amplifiers is performed so as to substantially reduce switching glitches in the output of the main amplifier.

Abstract: Two nulling amplifiers are used with an auto-zeroed differential amplifier. While one nulling amplifier is compensating the main amplifier, the other nulling amplifier is being zeroed for both differential mode (DM) and common mode (CM) offsets. By using two nulling amplifiers, one always connected to the main amplifier, a relatively constant open-loop gain is maintained for the main amplifier. A further improvement is make-before-break timing overlap of the switch operations between the two nulling amplifiers and the main amplifier. This ensures that the main amplifier is continuously driven by one or both null amplifiers, thereby maintaining a low impedance at the main amplifier auxiliary port. Both DM and CM offset sampling and precharging of each of the two nulling amplifiers is performed so as to substantially reduce switching glitches in the output of the main amplifier.

Abstract: A remote keyless entry (RKE) transponder has a noise alarm timer having a time interval used for determining whether a received signal meets a predefined condition within a time interval. If the received signal meets the predefined condition within the time interval, the noise alarm timer is disabled and the RKE transponder circuits are enabled so that normal operation in processing the desired signal commences. If the received signal does not meet the predefined condition within the time interval the noise alarm timer issues an alert signal, whereby appropriate action may be taken such as adjusting the channel input sensitivity, disabling a channel, or placing the RKE transponder into a sleep mode in order to reduce the power consumption caused by undesired input signals. A smart wake-up filter determines whether or not the input signal meets the predefined condition within the time interval.

Abstract: A programmable gain amplifier (PGA) controlled through a serial communications interface are fabricated on an integrated circuit (IC). A multiplexer (MUX) may also be included on the IC. The serial communications interface controls the gain of the PGA, MUX channel selection, and other functions of the PGA. Status of the PGA may also be obtained through the serial communications interface. By using a serial communications interface, the pin count of the PGA IC package may be kept to a minimum.

Abstract: A programmable gain amplifier (PGA) controlled through a serial communications interface are fabricated on an integrated circuit (IC). A multiplexer (MUX) may also be included on the IC. The serial communications interface controls the gain of the PGA, MUX channel selection, and other functions of the PGA. Status of the PGA may also be obtained through the serial communications interface. By using a serial communications interface, the pin count of the PGA IC package may be kept to a minimum.

Abstract: An output buffer, a slew-rate control circuit, a break-before-make circuit, and a current limited input amplifier are connected as a digital output driver. This provides a simple apparatus and method of switching current control and slew-rate control that limits power consumption of the digital output driver. To further minimize switching current, capacitors may be added to the break-before-make circuit. A comparator input circuit may be connected to the current limited input amplifier to form a comparator having a low-power-consuming digital output.

Abstract: An output buffer, a slew-rate control circuit, a break-before-make circuit, and a current limited input amplifier are connected as a digital output driver. This provides a simple apparatus and method of switching current control and slew-rate control that limits power consumption of the digital output driver. To further minimize switching current, capacitors may be added to the break-before-make circuit. A comparator input circuit may be connected to the current limited input amplifier to form a comparator having a low-power-consuming digital output.

Abstract: An operational amplifier is trimmed electrically using non-volatile fuses. The non-volatile fuses may be programmed electrically without destroying any passivation layers or other devices on the electronic component. In the case of an integrated circuit analog component, the trimming may be performed either at the wafer level or at the packaging level. The trimming may be performed specifically to adjust the quiescent current or offset voltage of the operational amplifier.

Abstract: Several calibration techniques for a precision relaxation oscillator with temperature compensation produces a stable clock frequency over wide variations of ambient temperature. The calibration techniques provide for different methods of determining CTAT current, PTAT current or the ratio of PTAT current to CTAT current. The calibration techniques provide different methods for determining CTAT and PTAT calibration values and for setting CTAT and PTAT calibration select switches.

Abstract: An analog electronic component, includes input and output pins, analog devices and non-volatile fuses. The analog devices are operative to perform analog signal processing on signals received via at least one input pin and to output processed signals on at least one output pin. The analog devices include adjustable elements. The non-volatile fuses are coupled to the adjustable processing elements and are electrically programmable via at least some of the input pins. Programming the non-volatile fuses adjusts the adjustable elements to alter characteristics of the analog signal processing.

Abstract: A precision temperature sensor produces a clock frequency which varies predictably over wide variations of ambient temperature. The invention has a oscillation generator, two independent current generators, a reference oscillator and a frequency counter. The outputs of the two independent current generators are combined to provide an approximately linear capacitor charging current which is directly proportional to changes in temperature. The capacitor charging current is used to drive the oscillation generator which outputs a clock frequency that is approximately linearly dependent on temperature with determinable slope and intercept. The frequency counter compares the output of the oscillation generator with the independent reference oscillator to compute a digital value for temperature. The precision temperature sensor is implemented on a single, monolithic integrated circuit.

Abstract: A fast start-up circuit for use in integrated circuits where there are internal nodes of reference circuits that need to be charged to a predetermined voltage level at a quicker rate than that delivered by the typical ramping up of supply power. The circuit a current driven approach, which is unique from the voltage driven approaches found in the prior art. The circuit is comprised of a high gain reference circuit and a current generator. The reference circuit is comprised of a bias generator and a high gain amplifier. The invention is characterized by a current generator which is capable of rapidly injecting relatively high levels of current into the reference circuit or sinking relatively high levels of current from the reference circuit or both. The invention is further characterized by a current driven feedback loop which deactivates the current generator once start-up is achieved and the high gain reference circuit approaches the quiescent point.