ZHCSHF4J May 2004 – January 2018 TPS51116
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 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 VDDQ SMPS, Light Load Condition
- 7.3.2 Low-Side Driver
- 7.3.3 High-Side Driver
- 7.3.4 Current Sensing Scheme
- 7.3.5 PWM Frequency and Adaptive On-Time Control
- 7.3.6 VDDQ Output Voltage Selection
- 7.3.7 VTT Linear Regulator and VTTREF
- 7.3.8 Controling Outputs Using the S3 and S5 Pins
- 7.3.9 Soft-Start Function and Powergood Status
- 7.3.10 VDDQ and VTT Discharge Control
- 7.3.11 Current Protection for VDDQ
- 7.3.12 Current Protection for VTT
- 7.3.13 Overvoltage and Undervoltage Protection for VDDQ
- 7.3.14 Undervoltage Lockout (UVLO) Protection, V5IN (PWP), V5FILT (RGE)
- 7.3.15 Input Capacitor, V5IN (PWP), V5FILT (RGE)
- 7.3.16 Thermal Shutdown
- 7.4 Device Functional Modes
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文檔支持
- 12機械、封裝和可訂購信息
封裝選項
請參考 PDF 數據表獲取器件具體的封裝圖。
機械數據 (封裝 | 引腳)
- RGE|24
- PWP|20
散熱焊盤機械數據 (封裝 | 引腳)
訂購信息
7.3.1 VDDQ SMPS, Light Load Condition
TPS51116 automatically reduces switching frequency at light load condition to maintain high efficiency. This reduction of frequency is achieved smoothly and without increase of VOUTripple or load regulation. Detail operation is described as follows. As the output current decreases from heavy load condition, the inductor current is also reduced and eventually comes to the point that its valley touches zero current, which is the boundary between continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when this zero inductor current is detected. As the load current further decreased, the converter runs in discontinuous conduction mode and it takes longer and longer to discharge the output capacitor to the level that requires next ON cycle. The ON-time is kept the same as that in the heavy load condition. In reverse, when the output current increase from light load to heavy load, switching frequency increases to the constant 400 kHz as the inductor current reaches to the continuous conduction. The transition load point to the light load operation IOUT(LL) (i.e. the threshold between continuous and discontinuous conduction mode) can be calculated in Equation 1:
where
- f is the PWM switching frequency (400 kHz)
Switching frequency versus output current in the light load condition is a function of L, f, VIN and VOUT, but it decreases almost proportional to the output current from the IOUT(LL) given above. For example, it is 40 kHz at IOUT(LL)/10 and 4 kHz at IOUT(LL)/100.