High-precision oscillator circuit with jitter frequency and slope compensation applied to switching power supply

Abstract

The invention belongs to the technical field of power management chips, and particularly relates to a high-precision oscillator circuit with jitter frequency and slope compensation applied to a switching power supply. A zero temperature coefficient current source generated by a reference current source is adopted to charge and discharge a capacitor, and a three-bit digital frequency modulation technology is utilized to change the frequency of an output oscillator by changing a charging mirror current; the total capacitance is changed by using the jitter frequency capacitance to improve EMI; and the slope compensation module is formed by adopting source negative feedback and can adjust the slope. On the basis of the high-precision output frequency of a traditional oscillator, the output frequency can be linearly switched within a wide range, slope-adjustable slope compensation current triangular wave signals are provided for a modulation circuit, the output of the oscillator can be trimmed within a certain range, and the output frequency of the oscillator can be adjusted within a certain range. And the requirements on the stability and high precision of the clock signal in a power management chip circuit are met.

Description

technical field [0001] The invention belongs to the technical field of power supply management chips, and in particular relates to a high-precision oscillator circuit with frequency shaking and slope compensation applied to switching power supplies. Background technique [0002] The development of science and technology is changing with each passing day. There have been huge changes in both hardware and functions, and are gradually developing in the direction of intelligence, large screen, and thinner. The problem of insufficient capacity. In this context, switching power converters have been widely used and are playing an increasingly important role in society, especially when the input voltage varies in a wide range, and the wide range of input voltage must be converted by step-up and step-down converters. The voltage is converted into a stable and suitable output voltage occasion. Power management chips are key devices in electronic equipment, widely used in various ele...

AI Technical Summary

Problems solved by technology

In an ideal state, the turn-on time of the switch tube can reach the full duty cycle, but due to various parasitic parameters in the actual circuit, the switch tube has a settling time and a turn-off time

At the same time, for the purpose of protecting the application circuit, the break-through phenomenon of the converter should be avoided, and a certain dead time is required, which makes it impossible for the conduction duty cycle of the switch tube of the converter to reach the full duty cycle.

For both boost and buck converters, the discontinuous duty cycle necessarily produces large dynamic disturbances on the output voltage

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