Freescale Semiconductor,inc.

Qadeer Ahmad Khan

Kulbhushan Misri

Sanjay Kumar Wadhwa

Divya Tripathi

Siddhartha Gk

Hidetaka Fukazawa

Jaideep Banerjee

Tushar S Nandurkar

Deeya Muhury

Sanjay Gupta

A compensation circuit and a method that compensates for process, voltage and temperature (PVT) variations in an integrated circuit that includes functional modules. The compensation circuit includes a signal generator, a first code generator, a second code generator, and a mapping module. The signal generator generates a first signal and a second signal depending on aligned process corner, voltage and temperature variations and skewed process corner variations respectively. The first code generator receives the first signal, and generates a first calibration code. The second code generator receives the second signal, and generates a second calibration code. The mapping module provides the first and second calibration codes for compensating for the aligned process corner, voltage and temperature variations and the skewed process corner variations associated with the functional modules respectively.

PVT variation detection and compensation circuit

A compensation circuit and a method for detecting and compensating for process, voltage, and temperature (PVT) variations in an integrated circuit. The integrated circuit includes plural logic modules that include PMOS transistors and NMOS transistors. The compensation circuit includes first and second functional modules, which generate first and second calibration signals. The first and the second calibration signals are used to compensate for the PVT variations in PMOS and NMOS transistors.

A power-on reset ('POR') methodology and circuit for an electronic circuit using multiple supply voltage domains asserts a reset signal upon ramp up of the first supply voltage signal, maintains the reset signal until all of the supply voltage signals have ramped up, and de-asserts the reset signal after all of the supply voltage signals have ramped up. Practical embodiments of the POR circuit include a control circuit that reduces static and/or dynamic current leakage associated with the operation of the POR circuit.

Sequence-independent power-on reset for multi-voltage circuits

A differential receiver circuit receives a differential input signal including first and second input signals (DP, DM) and generates a single-ended output signal. The receiver circuit includes first and second comparators that receive the differential input signal and generate respective first and second differential output signals. A current summer is connected to the first and second comparators and receives the first and second differential output signals and generates a third differential output signal. A differential to single-ended converter is connected to the current summer and receives the third differential output signal and generates the single-ended output signal. The differential input signal varies from a ground voltage level to an external reference voltage level (VUSB), while the first and second comparators are made with devices that operate at an internal reference voltage level that is lower than the external reference voltage level.

Differential receiver circuit

A buffer includes a source follower module and a pull-up/pull-down module that is connected to the source follower module. An output signal at the output terminal of the source follower module follows an input signal at the input terminal with a predetermined delay, independent of the Miller capacitance. The pull-up/pull-down module pulls the output of source follower to supply/ground rail.

Miller capacitance tolerant buffer element

A charge pump circuit for a high side drive circuit and a driver driving voltage circuit that stably output a voltage when input voltage is low. The charge pump circuit includes first and second transistors, first and second capacitors, and first to third diodes. The first capacitor has a high voltage side, connected to a load driving power supply voltage via the first diode, and a low voltage side, connected to the load driving power supply voltage via the first transistor or grounded via the second transistor driven in synchronization with the first transistor. The high voltage side is supplied, via the third diode, with a low side drive voltage that is as an output voltage of a low side charge pump, and functions to output high side drive voltage to a high side pre-driver circuit via the second diode.

Charge pump circuit for high side drive circuit and driver driving voltage circuit

A compensation circuit and a method for compensating for process, voltage and temperature (PVT) variations in an integrated circuit (IC). The IC includes several functional modules, each of which includes a set of functional units, and generates an output signal in response to an input signal. The compensation circuit includes a code generator and a logic module. The code generator generates a digital code for each functional unit. The digital codes are based on phase differences between the input signal and the output signal. The logic module generates calibration codes based on the digital codes. The calibration codes compensate for the PVT variations in the corresponding functional units.

A transmission line driver circuit that operates at a first voltage level is fabricated using devices that operate at a second, lower voltage level. The driver circuit includes a ramp generator that receives a speed signal and a data signal and generates a charge ramp signal and a discharge ramp signal. A pair of series connected source follower transistors have their gates connected to respective charge and discharge signal outputs of the ramp generator. The driver circuit output signal is generated at an output node between the sources of the NMOS and PMOS source follower transistors. A charge_ls generator circuit provides a charge_ls signal and a discharge_ls generator circuit provides a discharge_ls signal. A pair of protection transistors includes a first NMOS protection transistor and a first PMOS protection transistor, which are connected in series with respective ones of the source follower transistors, and their gates are connected to respective ones of the charge and discharge signals. The pair of protection transistors prevents the voltage across the NMOS and PMOS source follower transistors from exceeding their breakdown voltages.

Transmission line driver circuit

A transmission line driver with slew rate control includes high and low side ramp generators for generating charge and discharge ramp signals, respectively, which are input to respective comparators and a pair of source follower transistors. A pair of additional transistors is connected to the pair of source follower transistors and a pair of staggered drivers is connected to the pair of additional transistors.

Transmission line driver

A digital clock frequency doubler for increasing an input frequency of an input clock signal includes an input block, and a generator block. The input block receives the input clock signal, and generates a pulse signal having an ON period equal to the input clock signal period. The generator block is coupled to the input block. The generator block receives the pulse signal and divides a period of the pulse signal by a period of a high frequency digital signal and then generates an output clock signal with an output frequency that is about two times the input frequency.

Digital clock frequency doubler

A circuit for converting an input signal at a first voltage level to an output signal at a second voltage level uses only thin oxide transistors. The circuit includes a first unit operating at a first power supply voltage and receiving the input signal, a second unit operating at a second power supply voltage, and a third unit coupling the first unit to the second unit. The third unit enables generation of the output signal. Use of an extra fabrication mask for thick oxide transistors is avoided by using only thin oxide transistors.

High voltage level converter using low voltage devices

A band-gap reference circuit for generation of voltages and currents independent of process, voltage, and temperature includes three inversely proportional to absolute temperature (IPTAT) current generators. The IPTAT current generators generate three currents that are added to generate a current independent of the absolute temperature. The generated current is passed through a switched capacitor resistor to generate the band-gap reference voltage across the switched capacitor resistor.

Band-gap reference circuit

A bi-directional level shifter for shifting a digital signal from a low power supply voltage level to a high power supply voltage level and vice versa includes first and second I/O terminals, a first circuit operating at a low power supply voltage, and a second circuit operating at a high power supply voltage. The first circuit and the second circuit are connected to both of the I/O terminals. When a low voltage digital signal is applied at the first I/O terminal, a high voltage digital signal is generated at the second I/O terminal. Similarly, if a high voltage digital signal is applied at the second I/O terminal, a low voltage digital signal is generated at the first I/O terminal.

Bidirectional level shifter

A level shifter that shifts a low supply voltage input signal to a higher supply voltage output signal includes a first unit and a second unit. The first unit is connected to a high power supply voltage source and receives the input signal. The first unit acts as a startup circuit such that when the level shifter is switched on, the first unit discharges an output node if the input signal is a logic low, and when the input signal is a logic high, the first unit charges a control node to the voltage of the input signal. The second unit is connected to the first unit and the high power supply voltage source, and also receives the input signal. The second unit shifts the input signal to the higher supply voltage output signal. The level shifter operates only at the high power supply voltage.

Single supply level shifter

A switched capacitor current reference circuit generates an almost constant reference current across the parameters of process, voltage and temperature. A reference voltage is generated within the circuit, which eliminates the need for an external reference voltage. The reference current is generated by applying the reference voltage across a resistor emulated with a pair of switched capacitor circuits.

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New Delhi, India

Qadeer Ahmad Khan