Abstract: Systems and methods of a temperature compensated real-time clock are disclosed. The systems and methods can include measuring a temperature with a temperature sensor, detecting a temperature dependent frequency from an oscillator, inputting the temperature and determining a temperature estimate for the oscillator with an infinite impulse response filter, and determining a compensation factor, for the oscillator.

Abstract: Various embodiments of the invention relate generally to real-time clock circuit, and more particularly to systems, devices and methods of integrating two oscillators in one real-time clock circuit to generate accurate time of day over an industrial temperature range. A primary oscillator is employed to generate a first high precision clock while having a higher frequency and consuming more power; a secondary oscillator is employed to generate a second clock that has a low frequency and consumes less power, but may not meet the time accuracy requirement. When the real-time clock is provided with sufficient power (MSN mode), time of day is constantly tracked by the primary oscillator, but when the real-time clock is powered by a battery (SLEEP mode), time of day is tracked by the secondary oscillator while the primary oscillator is switched on at an update frequency to compensate errors in the time of day.

Abstract: A temperature compensated real-time clock systems and methods can include: measuring a temperature with a temperature sensor; detecting a temperature dependent frequency from an oscillator; inputting the temperature and determining a temperature estimate for the oscillator with an infinite impulse response filter; and determining a compensation factor, for the oscillator.

Abstract: Various embodiments of the invention relate generally to real-time clock circuit, and more particularly to systems, devices and methods of integrating two oscillators in one real-time clock circuit to generate accurate time of day over an industrial temperature range. A primary oscillator is employed to generate a first high precision clock while having a higher frequency and consuming more power; a secondary oscillator is employed to generate a second clock that has a low frequency and consumes less power, but may not meet the time accuracy requirement. When the real-time clock is provided with sufficient power (MSN mode), time of day is constantly tracked by the primary oscillator, but when the real-time clock is powered by a battery (SLEEP mode), time of day is tracked by the secondary oscillator while the primary oscillator is switched on at an update frequency to compensate errors in the time of day.