A low-temperature drift current-mode relaxation oscillator with feed-forward period control

A low-temperature drift current-mode relaxation oscillator circuit design using a feed-forward cycle control scheme is proposed. This design extracts the delay error from the circuit and compensates it to the charging process of the next cycle circuit. This design effectively solves the problem that the delay error is greatly affected by temperature and thus leads to excessive drift in the oscillation frequency. A relaxation oscillator circuit that can work at supply voltage from 3.2 V to 5 V is designed, The average temperature coefficient is 18.5 ppm/° C when the supply voltage is 3.3 V, and 14.3 ppm/° C when the supply voltage is 4.5 V in the temperature range of -40 °C to 120 °C, and its supply voltage coefficient is 0.27%/V from 3.2 V to 5.0 V. Notably, compared with the current-mode relaxation oscillator using the general design method, the temperature drift of the oscillator designed in this work is reduced by about 26% and 59% at 3.3 V and 4.5 V supply voltage, respectively, and the voltage drift is reduced by 75%.