High switching rate transconductance amplifier for active power factor corrector

Abstract

The invention discloses a high switching rate transconductance amplifier applied to an active power factor corrector, and mainly solves the problem that the conventional transconductance amplifier cannot timely process abnormal conditions in the active power factor corrector. The circuit comprises a bias current source, three current mirrors, a transconductance input stage and a switching rate enhancing circuit, wherein the transconductance input stage is a source cross-coupled pair; the bias current source has two paths which are respectively connected with the source cross-coupled pair, andis used for providing equal bias current is1 and is2; the switching rate enhancing circuit is connected between the three current mirrors and the source cross-coupled pair to form positive feedback in the circuit; the three current mirrors amplify current I1 and I2 output by the source cross-coupled pair and output current difference IO after comparison. The high switching rate transconductance amplifier can enlarge the maximum linear range of the output current and greatly improve the transient response speed, and can be applied to the active power factor corrector.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits and relates to an analog integrated circuit, in particular to a transconductance amplifier with a high conversion rate, which can be applied to an active power factor corrector in the design of a switching power supply. Background technique [0002] In the field of switching power supplies, the power factor corrector PFC is one of the effective methods to improve the power factor of electronic products and reduce harmonic interference. The transconductance amplifier can be widely used as an error amplifier in the active power factor corrector APFC, and it is an important part of the whole APFC converter to achieve a stable output voltage. It compares and amplifies the difference between the feedback signal INV and the reference voltage VREF of the output voltage of the active power factor corrector APFC divided by the resistor, and realizes the stability of the output voltage through t...

AI Technical Summary

Problems solved by technology

[0005] It can be seen that when driving a large capacitive load C L When ≥150pF, the slew rate of the above-mentioned existing transconductance amplifier is too small, the transient response speed is too slow, and the maximum linear range of the output current is small, which cannot deal with abnormal situations in the APFC system in time, and cannot meet the needs of high-speed electronic systems. work performance

If you want to improve its transient response speed, you can only increase i s Or B, and increasing any of these factors to meet the transient response speed can only lead to a substantial increase in power consumption of the system, which is difficult to meet the development requirements of low power consumption of integrated circuits

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