ZHCSB86E November 2011 – October 2021 TPS62150 , TPS62150A , TPS62151 , TPS62152 , TPS62153
PRODUCTION DATA
- 1 特性
- 2 應用
- 3 說明
- 4 Revision History
- 5 Device Comparison Table
- 6 Pin Configuration and Functions
- 7 Specifications
- 8 Detailed Description
- 9 Application and Implementation
- 10Power Supply Recommendations
- 11Layout
- 12Device and Documentation Support
- 13Mechanical, Packaging, and Orderable Information
8.4.3 100% Duty-Cycle Operation
The duty cycle of the buck converter is given by D = VOUT / VIN and increases as the input voltage comes close to the output voltage. In this case, the device starts 100% duty cycle operation turning on the high-side switch 100% of the time. The high-side switch stays turned on as long as the output voltage is below the internal set point. This allows the conversion of small input-to-output voltage differences, for example, for longest operation time of battery-powered applications. In 100% duty cycle mode, the low-side FET is switched off.
The minimum input voltage to maintain output voltage regulation, depending on the load current and the output voltage level, is calculated as:
where
- IOUT is the output current
- RDS(on) is the on-state resistance of the high-side FET
- RL is the dc resistance of the inductor