ST公司的L6726A单相PWM控制器嵌入了大电流驱动器,很容易就能建立起通用的有极好性能的DC/DC降压转换器,成本低.输入电压从5V到12V,输出电压可低至1.5V,可广泛应用于各种子系统的电源如MCH,IOCH和PCI等,存储器和端口电源,CPU和DSP电源以及分布式电源等.本文介绍了L6727和L6726A的主要性能,方框图以及应用电路图. L6726A Single phase PWM controller The L6726A and L6727 are low-cost single-phase PWM controllers, with embedded high-current drivers, enabling the easy creation of general purpose DC-DC step-down converters with excellent performance for a broad range of applications – from desktop PC sub-systems, such as memories and chipsets, to general-purpose power supplies. With their high level of integration, these compact SO-8 devices allow a significant reduction in the cost and size of the power supply. L6726A is a single-phase step-down controller with integrated high-current drivers that provides complete control logic, protections and reference voltage to realize in an easy and simple way general DC-DC converters by using a compact SO-8 package. Device flexibility allows managing conversions with power input VIN as low as 1.5V and device supply voltage ranging from 5V to 12V. L6726A provides simple control loop with transconductance error amplifier. The integrated 0.8V reference allows regulating output voltage with ±1% accuracy over line and temperature variations. Oscillator is internally fixed to 270kHz. L6726A provides programmable over current protection. Current information is monitored across the Low-Side mosfet RdsON saving the use of expensive and space-consuming sense resistors. FB disconnection protection prevents excessive and dangerous output voltages in case of floating FB pin.  主要特性: ■ Flexible power supply from 5V to 12V ■ Power conversion input as low as 1.5V ■ 1% output voltage accuracy ■ High-current integrated drivers ■ Adjustable output voltage ■ 0.8V internal reference ■ Sensorless and programmable OCP across Low-side RdsON ■ Oscillator internally fixed at 270kHz ■ Programmable soft-start ■ LS-LESS start up ■ Disable function ■ FB disconnection protection ■ SO-8 package 应用范围: ■ Subsystem power supply (MCH, IOCH, PCI...) ■ Memory and termination Supply ■ CPU & DSP power supply ■ Distributed power supply ■ General DC / DC converters  图1. L6726A方框图  图2. L6726A应用电路图 |
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