ZHCSIH1A July 2018 – September 2019 TPS56637
PRODUCTION DATA.
- 1 特性
- 2 应用
- 3 说明
- 4 修订历史记录
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 The Adaptive On-Time Control and PWM Operation
- 7.3.2 Mode Selection
- 7.3.3 Soft Start and Pre-Biased Soft Start
- 7.3.4 Enable and Adjusting Undervoltage Lockout
- 7.3.5 Output Overcurrent Limit and Undervoltage Protection
- 7.3.6 Overvoltage Protection
- 7.3.7 UVLO Protection
- 7.3.8 Thermal Shutdown
- 7.3.9 Output Voltage Discharge
- 7.3.10 Power Good
- 7.4 Device Functional Modes
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文档支持
- 12机械、封装和可订购信息
7.3.2.1 Eco-mode™ Control Scheme
When MODE pin is short to GND(≤10kΩ), the TPS56637 is set to Eco-mode™ control scheme to maintain high light load efficiency. As the output current decreases from heavy load condition, the inductor current is also reduced and eventually comes to a 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 the zero inductor current is detected. As the load current further decreases the converter runs into discontinuous conduction mode. The on-time is kept almost the same as it was in the continuous conduction mode so that longer time is needed to discharge the output capacitor with smaller load current to the level of the reference voltage. This process makes the switching frequency lower, proportional to the load current, and keeps the light load efficiency high. The transition point to the light load operation IOUT(LL) current can be calculated by Equation 1.
