A Tunable Frequency Relaxation Oscillator for DC-DC Switching Power Supply Applications

DC-DC switching power supply driver chips applied to the power supply systems of various electronic products require high-performance oscillators. Based on this requirement, this paper designs a tension oscillator with wide frequency modulation range and high accuracy. The oscillator is based on the 0.18μmBCD process library, using Cadence software in the chip system under the typical application environment simulation, the typical oscillation frequency of 991kHz, through the setting of peripheral resistors can be adjusted to the frequency range of 300kHz ∼ 2.5MHz; in the temperature range of -5O °C to 120 °C, the rate of change of frequency is 1.7%; in the 3.5V to 6V The frequency variation rate is 0.8% in the supply voltage range of 3.5V to 6V. Simulation results show that the oscillator performs well and is suitable for DC-DC switching power supplies.