A Buck Converter with Adaptive Slope Compensation

Abstract

A buck converter with adaptive slope compensation, the first transconductance amplifier calculates the difference between the feedback voltage and the reference voltage to obtain the original control current; the second transconductance amplifier calculates the difference between the feedback voltage and the reference voltage, and the difference current The current superimposed with the second current source is sent to the second capacitor, and the signal output by the Q output terminal of the D flip-flop controls the second switch to form a slope voltage with a variable slope, and then generates a variable slope through the fourth transconductance amplifier The ramp current; the third transconductance amplifier forms a current containing output voltage information according to the voltage difference between the first voltage source and ground; the current multiplier multiplies the original control current by the ramp current with variable slope and divides it by the output voltage information current to obtain an adaptive ramp current with control information, and then use the first resistor to convert the adaptive ramp current into an adaptive ramp voltage signal and connect it to the positive input terminal of the first comparator, and compare the signal to control the drive module.

Description

technical field [0001] The invention belongs to the technical field of analog integrated circuits, and in particular relates to an adaptive slope compensation Buck converter. Background technique [0002] In the traditional constant on-time (COT, Constant On-Time) controlled Buck converter with fixed slope compensation, such as figure 1 As shown, the inductor current and the voltage generated by the sense resistor V L , EA output control voltage V C and the fixed ramp RAMP are compared whenever the inductor current produces a voltage V L When it is lower than the sum of Vc and RAMP, the output of comparator COMP1 is high, producing a constant on-time T on , so that the inductor current increases; when T on After the end, the inductor current decreases and returns to the valley value again, entering the next T on cycle, thereby controlling the Buck converter. [0003] The traditional fixed-slope compensation constant on-time controlled Buck variator has a good signal-to...

AI Technical Summary

Problems solved by technology

However, the traditional fixed-slope compensation constant on-time control buck converter has the following problems: (1) Compared with the traditional constant on-time control buck converter, due to the introduction of the slope, it leads to more introduction in the frequency domain a pole, causing the system to slow down in transient response

(2) In addition, when the inductor current ripple is large, because the slope of the inductor current and the voltage generated by the sampling resistor is large enough, there is no need for excessive slope compensation. Excessive compensation will reduce the unity gain bandwidth and affect responding speed

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