Codex Corporation

Motorola Corporation

Other

Benjamin C Peterson

Ahmad H Atriss

Lanny L Parker

Dean W Mueller

Yoseph L Linde

Yigal Brandman

A digital controlled oscillator (14) generates an oscillator clock that is phase locked to a reference clock. A control circuit (12) generates a reset signal from the reference clock that sets the edges of the oscillator signal in line with an edge of the reference clock. The reset signal must have correct timing and duration. A course tune detector (16, 18) monitors the oscillator clock and generates course tune control signals (CT) that adjust the reset signal pulse width and the oscillator signal frequency by adding and removing capacitors from the inverters in the control circuit and digital controlled oscillator. A phase comparator (22) compares the reference clock and the oscillator clock. A fine tune detector (20) monitors the phase comparison and generates fine tune control signals (FT) that make fine adjustments to the pulse width of the reset signal and the frequency of the oscillator signal.

Digital controlled oscillator and method thereof

A bias voltage for a VCO is generated by monitoring UP and DOWN control signals from a charge pump and generating first and second output signals upon detecting a predetermined number of consecutive UP pulses or DOWN pulses. The first output signal causes a shift register pre-loaded with a data pattern having one odd logic state to shift one bit location to left, while the second output signal moves the odd logic state one bit location to the right. The bias voltage to the VCO is selected based on the odd logic state bit location. Any variation in VCO output frequency due to intermittent ground bounce is eliminated by requiring a consecutive number of UP pulses or DOWN pulses before moving the VCO bias point.

VCO bias generator in a phase lock loop

A digital clock circuit generates a high-speed clock and window pulses substantially centered about transitions of the high-speed clock in one quadrant of an integrated circuit (IC) and routes the high-speed clock and window pulses to other quadrants of the IC where a low-speed clock generator develops a low-speed clock signal from the window pulses. A control circuit checks alignment between the high-speed and low-speed clock signals and adjusts first and second shift registers to control the delay in generating the low-speed clock as necessary to maintain alignment. The first shift register controls the falling edge of the low-speed clock signal and the second shift register controls the rising edge of the low-speed clock signal.

Circuit and method of synchronizing clock signals

A voltage controlled oscillator runs at full speed to generate an output frequency dependent on temperature and process variation. First and second clock signals are generated from the oscillator signal, while third and fourth clock signals are developed in response to an input clock signal. The number of clock signals occurring during a first state of the third clock signal are counted for providing a plurality of output signals also indicative of the temperature and process variation. The plurality of output signals compensate an input signal for the temperature and process variation for providing an output signal.

Circuit and method of sensing process and temperature variation in an

A phase lock loop monitors a first digital signal and generates a second digital signal operating substantially at frequency and in-phase with the first digital signal. A programmable divider latches a program integer for providing a latch integer, compares the latch integer to a constant integer, and generates a flag signal having a first state when the latch integer mismatches the constant integer and a second state when the latch integer matches the constant integer. The latch integer is decremented when the flag signal has the first state. The flag signal is delayed in response to first and second clock signals for providing the second digital signal having a frequency determined by the program integer. The first and second digital signals are applied to a lock detection circuit for providing a lock detection signal.

Programmable frequency divider in a phase lock loop

A phase lock loop operates independent of temperature and process variation by digitally loading a VCO until reaching the desired operating frequency. The VCO reaches a high output frequency even under worst case processing by controlling multiple current mirrors to increase inverter switching current without slowing the response of the VCO to changes in loop node voltage. An Initialize-to-VDD circuit sets the loop node voltage to V.sub.DD so that the load control circuit need only increase loading to slow down the VCO to the desired operating frequency. A frequency range detector monitors the output frequency of the VCO and passes control signals to a load control circuit to activate digital loads and slow down the VCO to the desired operating frequency.

Voltage controlled oscillator operating with digital controlled loads in

A charge pump in a phase lock loop equalizes the charge and discharge currents flowing into the filter capacitor independent of the loop node voltage for providing a linear VCO output frequency. The potential at the output of the charge pump determines whether the charging/discharging current is decreased or increased. An active up control signal to increase VCO output frequency and a low level potential at the output of the charge pump limits the charging current to the loop filter while increasing the discharge current. An active down control signal to decrease the VCO output frequency and a high potential at the output of the charge pump limits the discharging current while increasing the charge current. The voltage change at the output of the charge pump in response to the up control signal is made equal to the voltage change during the down control signal for providing equal charge and discharge currents to the loop filter independent of the loop voltage.

Phase lock loop charge pump with symmetrical charge and discharge

High frequency voltage controlled oscillator

A phase lock loop monitors a first digital signal and generates a second digital signal operating substantially at frequency and in-phase with the first digital signal. The first and second digital signal are applied to a lock detection circuit for generating a first digital output signal having a first logic state from a mutually exclusive combination of the first and second digital signals. The first logic state of the first digital output signal is compared with a time slot window formed by a control signal for generating a true lock detection signal when the first logic state of the first digital output signal occurs within the time slot window and a false lock detection signal when the first logic state of the first digital output signal occurs outside the time slot window.

Lock detection for a phase lock loop

Frequency range detector

A power on reset circuit uses a first inverter with hysteresis operating in response to a first power supply potential to develop a first reset signal when the first power supply potential is greater than a first predetermined threshold. A second inverter with hysteresis also operates in response to the first power supply potential for developing a second reset signal when the first power supply potential is greater than a second predetermined threshold. The first reset signal disables the second inverter until the first power supply potential reaches the first predetermined threshold. A delay circuit delays the second reset signal to ensure the first power supply potential is fully operational before indicating a ready condition.

Power on reset circuit having hysteresis inverters

A voltage controlled oscillator (VCO) generates a 50% duty cycle clock. The 50% duty cycle clock is derived directly from the operating frequency of the VCO thereby abating the need for the VCO to operate at twice the desired clock frequency. This allows the VCO to be utilized in high frequency phase-locked loop systems.

Voltage controlled oscillator having 50% duty cycle clock

A voltage controlled oscillator (VCO) includes a voltage controlled load. The voltage controlled load supplies additional capacitive loading to the VCO, via a transmission gate, at low frequencies to decrease the frequency-gain factor of the VCO. Moreover, at high frequencies, the effect of the voltage controlled load is minimized by turning off the transmission gate thereby allowing the VCO to operate at maximum frequency for worst case speed conditions.

Voltage controlled oscillator with controlled load

A logic array which is small in size and low in power dissipation uses only one clock signal. The array is fully precharged by precharging a first portion and a second portion and then applying ground to the first portion while delayably applying the ground to the second portion. The address is read into the first portion during the precharging to speed up operation of the array.

High speed fully precharged programmable logic array

Disclosed is a latching type sense amplifier to be used with a static IFGET random access memory which provides an improved memory circuit. The sense amplifier employs a pair of depletion mode devices which serve both as load devices for the latch and as means for coupling a pair of bit lines to the sense amplifier. Prior to sensing, both the bit lines and the switching nodes of the latch are precharged and balanced. The selection of a memory cell induces a small differential voltage across the bit lines, causing one of the depletion mode load devices to be more conductive than the other. When the latch is enabled, regenerative amplification causes the latch to seek one of two stable states as determined by the relative conductivities of the two depletion mode load devices, thereby latching the state of the data stored in the selected memory cell.

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Tempe, AZ, United States of America

Benjamin C Peterson