Power supply converter and error amplifier

Abstract

The invention discloses a power supply converter which comprises an output circuit with a power switch, a voltage feedback circuit, an error amplifier and a pulse width modulating comparator, wherein the output circuit is used for modulating an input voltage into an output voltage under the on-off control of the power switch; the voltage feedback circuit is used for sampling the output voltage toobtain a feedback voltage; the error amplifier clamps an output error amplifying signal and is used for carrying out error amplification on a reference voltage and the feedback voltage to obtain an error amplifying voltage; the pulse width modulating comparator is used for comparing the error amplifying voltage with a triangular wave signal to generate a pulse width modulating signal; and the pulse width modulating signal is used for controlling the on-off of the power switch. The power supply converter effectively improves the load response by introduction of the error amplifier which can clamp the output error amplifying signal.

Description

【Technical field】 [0001] The invention relates to the field of circuits, in particular to a power converter and an error amplifier. 【Background technique】 [0002] Power converters are widely used in various portable electronic devices, and a boost DC / DC converter (boostDC / DC converter) is one of them. [0003] figure 1 It is a schematic circuit diagram of a step-up DC / DC converter. Please refer to figure 1 As shown, the boost DC / DC converter 100 includes a boost output circuit 110 , a voltage feedback circuit 120 , an error amplifier 130 , a pulse width modulation comparator 140 and a logic control circuit 150 . [0004] The boost output circuit 110 includes an inductor L, a diode D, an NMOS transistor MN1 and a capacitor Cout. One end of the inductor L is connected to the input voltage Vin, the other end is connected to the anode of the diode D, and the cathode of the diode D is connected to one end of the capacitor Cout. The intermediate node voltage of the diode D an...

AI Technical Summary

Problems solved by technology

However, the above two methods have their limitations: firstly, simply increasing the response speed and bandwidth of the loop will bring difficulties to the frequency compensation of the feedback loop, making the feedback loop unstable; secondly, increasing the output capacitance will also affect the frequency compensation of the feedback loop. Compensation of the feedback loop, and a capacitor with a large value will have a larger volume and higher cost

[0010] It should be noted that here we only take the step-up DC / DC conversion circuit as an example to introduce the common load response problems in power conversion circuits. Other power conversion circuits including pulse width modulation comparators and error amplifiers also have the same problems. Such a load response problem

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