TPS54339EDDA

TPS54339E是一款自适应接通时间D-CAP2™模式同步降压转换器。可帮助系统设计人员通过一个低成本、低组件数、低待机电流解决方案来完成各种终端设备的电源总线调节器集。主控制环路采用D-CAP2™模式控制，无需外部补偿组件便可实现极快的瞬态响应。自适应接通时间控制支持较高负载状态下的脉宽调制(PWM)模式与轻负载下的Eco-mode™工作模式之间的无缝转换。Eco-mode™使TPS54339E能够在较轻负载状况下保持高效率。专有电路还有助于该器件适应诸如POSCAP或SP-CAP等低等效串联电阻(ESR)输出电容器以及超低ESR陶瓷电容器。工作输入电压介于4.5V至18V之间，输出电压可在0.76V与7V之间进行设定，特有一个可调软启动时间，采用8引脚DDA封装，并针对 -40°C到85°C的工作温度范围内的运行而设计。

The TPS54339E is a 3-A synchronous step-down (buck) converter with two integrated N-channel MOSFETs. It operates using D-CAP2™ mode control. The fast transient response of D-CAP2™ control reduces the output capacitance required to meet a specific level of performance. Proprietary internal circuitry allows the use of low ESR output capacitors including ceramic and special polymer types.

The main control loop of the TPS54339E is an adaptive on-time pulse width modulation (PWM) controller that supports a proprietary D-CAP2™ mode control. D-CAP2™ mode control combines constant on-time control with an internal compensation circuit for pseudo-fixed frequency and low external component count configuration with both low ESR and ceramic output capacitors. It is stable even with virtually no ripple at the output.

TPS54339E uses an adaptive on-time control scheme and does not have a dedicated on board oscillator. The TPS54339E runs with a pseudo-constant frequency of 600 kHz by using the input voltage and output voltage to set the on-time one-shot timer. The on-time is inversely proportional to the input voltage and proportional to the output voltage; therefore, when the duty ratio is VOUT/VIN, the frequency is constant.

The TPS54339E is designed with Auto-Skip Eco-mode™ to increase light load efficiency. As the output current decreases from heavy load condition, the inductor current is also reduced and eventually comes to point that its rippled valley touches zero level, which is the boundary between continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when its zero inductor current is detected. As the load current further decreases the converter run into discontinuous conduction mode. The on-time is kept almost the same as is was in the continuous conduction mode so that it takes longer time to discharge the output capacitor with smaller load current to the level of the reference voltage.

The soft start function is adjustable. When the EN pin becomes high, 6 μA current begins charging the capacitor which is connected from the SS pin to GND. Smooth control of the output voltage is maintained during start up.

• D-CAP2™模式支持快速瞬态响应
• 低输出纹波，支持陶瓷输出电容器
• 宽泛的输入电压范围：4.5V至23V
• 输出电压范围：0.76V至7.0V
• 高效率集成型场效应晶体管(FET)
• 针对更低占空比应用进行了优化
• -140mΩ（高侧）与70mΩ（低侧）
• 高效率，关断时流耗少于10μA
• 高初始带隙基准精度
• 可调软启动
• 预偏置软启动
• 600kHz开关频率(fSW)
• 逐周周期限流
• 自动跳跃Eco-mode™为了在轻负载下实现高效率

• 低电压系统的广泛应用
• 数字电视电源
• 高清Blu-ray Disc播放器
• 网络家庭终端设备
• 数字机顶盒(STB)