Linear LTC3610 12A/24V电源应用方案

Linear公司的LTC3610 单片同步降压DC/DC转换器能从4V-24V(最大28V)输入电压中提供高达12A的输出电流,可以广泛应用在点负载稳压和分布式电源系统.本文介绍了它的主要性能,功能方框图以及不同输入电压,不同输出电压和不同开关频率的应用电路图.

LTC3610 12A, 24V Monolithic Synchronous Step-Down DC/DC Converter
The LTC 3610 is a high efficiency, monolithic synchronous step-down DC/DC converter that can deliver up to 12A output current from a 4V to 24V (28V maximum) input supply. It uses a valley current control architecture to deliver very low duty cycle operation at high frequency with excellent transient response. The operating frequency is selected by an external resistor and is compensated for variations in VIN and VOUT.

The LTC3610 can be configured for discontinuous or forced continuous operation at light load. Forced continuous operation reduces noise and RF interference while discontinuous mode provides high efficiency by reducing switching losses at light loads.

Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and an optional short-circuit shutdown timer. Soft-start capability for supply
sequencing is accomplished using an external timing capacitor. The regulator current limit is user programmable.

A power good output voltage monitor indicates when the output is in regulation. The LTC3610 is available in a compact 9mm × 9mm QFN package.

主要特性:
■ 12A Output Current
■ Wide VIN Range = 4V to 24V
■ Internal N-Channel MOSFETs
■ True Current Mode Control
■ Optimized for High Step-Down Ratios
■ tON(MIN) ≤100ns
■ Extremely Fast Transient Response
■ Stable with Ceramic COUT
■ ±1% 0.6V Voltage Reference
■ Power Good Output Voltage Monitor
■ Adjustable On-Time/Switching Frequency
■ Adjustable Current Limit
■ Programmable Soft-Start
■ Output Overvoltage Protection
■ Optional Short-Circuit Shutdown Timer
■ Low Shutdown IQ: 15μA
■ Available in a 9mm × 9mm 64-Pin QFN Package

应用:
■ Point of Load Regulation
■ Distributed Power Systems



图1. LTC3610功能方框图



图2.5V-24V输入输出2.5V/12A(550kHz)设计案例

以下是典型应用电路图:



图3. 3.3V输入,输出1.5V/12A(750kHz)电路图



图4. 5V-24V输入,输出1.2V/12A(550kHz)电路图



图5. 5V-24V输入,输出1.8V/12A(1000kHz)电路图



图6. 14V-24V输入,输出12V/12A(550kHz)电路图