ME2109ME2139ME2149优秀升压IC设计方案.doc

ME2109 ME2139 ME2149移动电源优秀升压 IC 外置 MOSFET MEM2306 实际效率高，在 1.5A-3A 最佳低成本升压方案，IC 与外围器件温度可保证在常温 ME2139 系列是采用 CMOS 升压型开关稳压器，其主要包括一个参考电压源，一个振荡电路，一个误差放 大器，一个相位补偿电路，通过 PWM / PFM 切换控制电路。随着外部低通态电阻 N 沟道功率 MOS，本产 品适用于需要高效率和高输出电流的应用。 ME2139 系列交换机操作 PFM 控制电路的占空比为 15％的 PWM/ PFM 切换控制电路在轻负载，并防止 IC 工作电流效率下降。 特点： ●低电压工作：启动保证从 0.9 V（IOUT = 1 mA） ●占空比：内置 PWM/ PFM 切换控制电路 15?78％。 ●振荡频率：1.0MHz 的 ●外部部件：线圈，二极管，电容器和晶体管 ●输出电压范围：1.5V?6.5 V ●输出电压精度：±2％ ●软启动功能：2 毫秒。 ●包装：SOT23-5 应用范围： ●MP3 播放器，数字音频播放器 ●数码相机，GPS，无线收发器 ●便携式设备  ME2139 ULTRA-SMALL PACKAGE PWM/PFM SWITCHING CONTROL  Description STEP-UP SWITCHING REGULATOR Feature The ME2139 series is a CMOS step-up switching regulator which mainly consists of a reference voltage source, an oscillation circuit, an error amplifier, a phase compensation circuit, a PWM/PFM switching control circuit. With an external low-ON-resistance Nch Power MOS, this product is applicable to applications requiring high efficiency and high output current. The ME2139 series switches its operation to the PFM control circuit whose duty ratio is 15 % with to the PWM/PFM switching control circuit under a light load and to prevent decline in the efficiency by IC operation current. Selection Guide  ? Low voltage operation: Start-up is guaranteed from 0.9 V(IOUT =1 mA ) ? Duty ratio: Built-in PWM/PFM switching control circuit 15 to 78 % . ? oscillator frequency：1.0MHz ? External parts: coil, diode, capacitor, and transistor ? Output voltage range: 1.5V ~6.5 V ? Output voltage accuracy：±2% ? Soft start function: 2 mS. ? PACKAGE：SOT23-5 Typical Application ? MP3 players, digital audio players ? Digital cameras, GPS, wireless transceiver ? Portable devices  Pin Configuration TYPE POSFIX PACKAGESWICHING TRANSISTORCE FUNCTIONVDD FUNCTIONFB FUNCTION FEATURE ME2139F M5 SOT23-5External Transistor Yes Yes Yes Ext+FB   Pin information SOT-23-5  ME2139F Pin Number Pin Name Function SOT23-51