Patent application number | Description | Published |
20110260753 | Level Shifter with Balanced Duty Cycle - A level shifter and method are provided for balancing a duty cycle of a signal. An input circuit receives a differential logic signal with two complimentary logic levels. A level transition balancing circuit balances the rise and fall times of a level shifted version of each complimentary logic level during a transition from a first to a second of the logic levels and a level shift. A logic element stores and provides outputs of the level shifted versions of the logic levels. The level transition balancing circuit can include a capacitor in parallel with a transfer element for each input. The capacitor destabilizes inputs to the logic element and balances the transition using a capacitance and a level previously stored in the logic element. | 10-27-2011 |
20120015617 | Squelch Detection Circuit and Method - A squelch detection circuit and method involves a first comparator coupled to a complimentary input signal pair and having a first polarity output. A second comparator coupled to the complimentary input signal pair has a second polarity output. An offset associated with complimentary input signal pair establishes a positive squelch threshold and a negative squelch threshold. A calibration unit coupled to the first comparator and the second comparator generates a digital output including threshold settings and calibration settings to the first comparator and to the second comparator. The digital output can be associated with establishing the offset and with calibrating the positive squelch threshold and the negative squelch threshold. | 01-19-2012 |
20120194253 | High Voltage Tolerant Differential Receiver - A high voltage tolerant differential receiver circuit includes a voltage divider ladder that is operative to divide in half differential input signals that are greater than threshold voltages of the voltage divider ladder. A pass gate circuit is operative to receive differential input signals that are below the threshold voltage of the voltage divider ladder. Outputs from the voltage divider ladder and the pass gate circuit are provided to separate comparators. Output from the comparators are combined to generate a signal in the voltage domain of receiver circuitry. | 08-02-2012 |
20120194254 | High Voltage Tolerant Receiver - A high voltage tolerant single ended receiver circuit includes a voltage divider that is operative to divide in half single ended input signals that are greater than the threshold voltages of the voltage divider. A pass gate circuit is operative to receive single ended signals that are below the threshold voltages of the voltage divider. Output from the voltage divider is coupled to a first input of a modified Schmitt trigger circuit to control a high threshold level of the Schmitt trigger circuit. Output from the pass gate circuit is coupled to a second input of the modified Schmitt trigger circuit to control a low threshold level of the Schmitt trigger circuit. | 08-02-2012 |
20120212265 | DELAY CELL FOR CLOCK SIGNALS - An integrated circuit for delaying a clock signal using a delay cell is described. The integrated circuit includes a current starved inverter. The current starved inverter includes a switched capacitor current source with a first dummy inverter, a first amplifier coupled to the first dummy inverter and a first capacitor coupled to the first amplifier via a first switch. The current starved inverter also includes a first transistor coupled to the current source. The integrated circuit also includes a second capacitor. A delay applied to the clock signal is dependent on a ratio between the first capacitor and the second capacitor. The first capacitor and the second capacitor may be located in proximity such that process, voltage and temperature variations affect the first capacitor and the second capacitor similarly and the delay applied to the clock signal is independent of process, voltage and temperature variations. | 08-23-2012 |
20120235730 | CHARGE PUMP SURGE CURRENT REDUCTION - Techniques for reducing surge current in charge pumps. In an exemplary embodiment, one or more switches coupling a terminal of a flying capacitor to a voltage supply are configured to have variable on-resistance. When the charge pump is configured to switch a gain mode from a lower gain to a higher gain, the one or more variable resistance switches are configured to have a decreasing resistance profile over time. In this manner, surge current drawn from the voltage supply at the outset of the gain switch may be limited, while the on-resistance during steady-state charging and discharging may be kept low. Similar techniques are provided to decrease the surge current from a bypass switch coupling the supply voltage to a positive output voltage of the charge pump. | 09-20-2012 |
20120236444 | CHARGE PUMP ELECTROSTATIC DISCHARGE PROTECTION - Techniques for electrostatic discharge (ESD) protection for amplifiers and other circuitry employing charge pumps. In an exemplary embodiment, a Vneg switch coupling a second flying capacitor node to a negative output voltage node is closed in response to an ESD event being detected between a supply voltage node and the negative output voltage node. A ground switch coupling a ground node to the second flying capacitor node is closed in response to an ESD event being detected between the ground node and the negative output voltage node. The Vneg switch is further closed in response to the ESD event being detected between the ground node and the negative output voltage node. Further techniques are disclosed for providing on-chip snapback clamps at the output of a power amplifier coupled to the charge pump to protect against ESD events as defined by the standard IEC 61000-4-2. | 09-20-2012 |
20130043922 | SUPPLY COLLAPSE DETECTION CIRCUIT - A supply collapse detection circuit is described. The supply collapse detection circuit includes threshold detection circuitry coupled to a first power supply and to a second power supply that provides a second voltage. The supply collapse detection circuit also includes supply collapse output circuitry coupled to the threshold detection circuitry to receive a detection signal when the second voltage drops. The supply collapse output circuitry includes an output node to provide an output signal indicating the drop. The supply collapse detection circuit additionally includes feedback circuitry coupled to the first power supply, to the threshold detection circuitry and to the supply collapse output circuitry. The feedback circuitry reduces leakage when the second voltage drops. | 02-21-2013 |
20130223649 | LOAD CURRENT SENSING - Techniques for sensing current delivered to a load by a differential output stage, e.g., in a Class D amplifier. In one aspect, voltages across sense resistors coupled in series with first and second branches of the differential output stage are low-passed filtered and digitized. The sense resistors may be coupled in series with the sources of transistors of the first and second branches, wherein the transistors are selectively switchable on and off by input voltage driving voltages. The input driving voltages may correspond to a ternary voltage waveform such that during a given phase, the two transistors coupled in series with the sense resistors may be turned off. Further aspects provide for the first and second branches having cascoded NMOS and/or PMOS transistors, and the sense resistors being provided between a pair of cascoded transistors. | 08-29-2013 |
20130257398 | SYSTEM AND METHOD FOR SUPPRESSION OF PEAKING IN AN EXTERNAL LC FILTER OF A BUCK REGULATOR - Disclosed are systems and methods for suppressing voltage peaking in a buck regulator. In one aspect, a buck regulator comprises: a pulse-width modulator (PWM) that generates a pulsed signal; a switch operable to selectively connect the regulator to a DC power supply in response to the pulsed signal and output a pulsed output DC signal; a filter for filtering out high frequency noise from the pulsed output DC signal and generating a regulated output signal; an integrator for comparing the pulsed output DC signal with a reference voltage signal and generating an error signal for input to the PWM; a subtractor operable to subtract the reference voltage signal from the filtered output signal to generate an error feedback signal; and an adder operable to add the error feedback signal to the error signal for input to the pulse-width modulator in order to suppress voltage peaks in the filtered output signal. | 10-03-2013 |
20140029611 | SYSTEMS AND METHODS FOR SHARING A SERIAL COMMUNICATION PORT BETWEEN A PLURALITY OF COMMUNICATION CHANNELS - An apparatus for sharing a serial communication port between a plurality of communication channels is described. The apparatus comprises a transceiver that manages communications over the serial communication port. The apparatus also includes a multiplexer coupled to the transceiver, wherein the multiplexer multiplexes the plurality of communication channels. The apparatus also includes identification information circuitry coupled to the multiplexer, wherein the identification information circuitry adds identification information to data from the plurality of communication channels that enables the plurality of communication channels to share the serial communication port. The serial communications port and the multiplexer permit communication between integrated circuits that meet at least one latency metric for the plurality of communication channels when the plurality of communication channels are active. | 01-30-2014 |
20140065773 | ELECTROSTATIC DISCHARGE (ESD) SILICON CONTROLLED RECTIFIER (SCR) STRUCTURE - A structure includes first and second silicon controlled rectifiers (SCRs) formed in a substrate. The first and the second SCRs each include at least one component commonly shared between the first and the second SCRs. | 03-06-2014 |
20140098447 | ELECTROSTATIC DISCHARGE PROTECTION FOR CLASS D POWER AMPLIFIERS - Electrostatic discharge protection for Class D power amplifiers is disclosed. In an exemplary embodiment, an apparatus includes an amplifier having an output transistor coupled to an interface pad, a snapback supply clamp coupled across first and second supplies of the amplifier and configured to provide a clamp voltage across the first and second supplies during ESD event; and a trigger circuit coupled to the output transistor, the trigger circuit configured to detect the clamp voltage and to enable the output transistor to provide a discharge path from the interface pad to the second supply when the clamp voltage is detected. | 04-10-2014 |
20140177850 | SWITCH TECHNIQUES FOR LOAD SENSING - Techniques for sensing the resistance of a load. In an aspect, a sense resistor is provided in series with the load. Each terminal of the sense resistor is alternately coupled via switches to a sense amplifier. A second input of the sense resistor is coupled to a terminal of the load. The voltage drop across the load and the voltage drop across the load plus sense resistor are alternatively measured. These voltage drops may be digitized and used to compute a resistance of the load using, e.g., a digital processor. | 06-26-2014 |
20140204488 | ESD CLAMPING TRANSISTOR WITH SWITCHABLE CLAMPING MODES OF OPERATION - In a particular embodiment, an apparatus includes an electrostatic discharge (ESD) clamping transistor coupled to a ground terminal of a device. The apparatus further includes a switch coupled between a body terminal of the ESD clamping transistor and the around terminal. | 07-24-2014 |
20140254051 | DEVICES AND METHODS FOR CALIBRATING AND OPERATING A SNAPBACK CLAMP CIRCUIT - A device includes a snapback clamp circuit configured to clamp a supply voltage in response to the supply voltage exceeding a trigger voltage level. In at least one embodiment, the snapback clamp circuit includes a clamp transistor and a programmable resistance portion that is responsive to a control signal to calibrate the trigger voltage level. Alternatively or in addition, the snapback clamp circuit may include a programmable bias device configured to calibrate the trigger voltage level by biasing a gate terminal of the clamp transistor. In another particular embodiment, a method of calibrating a snapback clamp circuit is disclosed. In another particular embodiment, a method of operating an integrated circuit is disclosed. | 09-11-2014 |