ZHCSH21A October 2017 – February 2018 UCC28780
PRODUCTION DATA.
- 1 特性
- 2 應(yīng)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
Detailed Pin Description
- 7.3.1 BUR Pin (Programmable Burst Mode)
- 7.3.2 FB Pin (Feedback Pin)
- 7.3.3 VDD Pin (Device Bias Supply)
- 7.3.4 REF Pin (Internal 5-V Bias)
- 7.3.5 HVG and SWS Pins
- 7.3.6 RTZ Pin (Sets Delay for Transition Time to Zero)
- 7.3.7 RDM Pin (Sets Synthesized Demagnetization Time for ZVS Tuning)
- 7.3.8 RUN Pin (Driver Enable Pin)
- 7.3.9 SET Pin
- 7.4
Device Functional Modes
- 7.4.1 Adaptive ZVS Control with Auto-Tuning
- 7.4.2 Dead-Time Optimization
- 7.4.3 Control Law across Entire Load Range
- 7.4.4 Adaptive Amplitude Modulation (AAM)
- 7.4.5 Adaptive Burst Mode (ABM)
- 7.4.6 Low Power Mode (LPM)
- 7.4.7 Standby Power Mode (SBP)
- 7.4.8 Startup Sequence
- 7.4.9 Survival Mode of VDD
- 7.4.10 System Fault Protections
- 7.4.11 Pin Open/Short Protections
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application Circuit
- 8.2.1 Design Requirements
- 8.2.2 Detailed Design Procedure
- 8.2.3 Application Curves
- 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(shù)據(jù)表獲取器件具體的封裝圖。
機械數(shù)據(jù) (封裝 | 引腳)
- D|16
- RTE|16
散熱焊盤機械數(shù)據(jù) (封裝 | 引腳)
- RTE|16
訂購信息
8.2.2.2.1 Primary-to-Secondary Turns Ratio (NPS)
NPS influences the design tradeoffs on the voltage rating between primary and secondary switches, and the balance between the magnetic core and winding loss of the transformer, which are explained in detail as follows:
- Maximum NPS (NPS(MAX)) is limited by the maximum derated drain-to-source voltage of QL (VDS_QL(MAX)). In the expression below, ?VCLAMP is the voltage above the reflected output voltage. It can be either the ripple voltage of CCLAMP in AAM mode, or the voltage over-charge of CCLAMP by the leakage energy as QH is disabled in LPM mode. VO is the output voltage, and VF is the forward voltage drop of the secondary rectifier.
- Minimum NPS (NPS(MIN)) is limited by the maximum derated drain-to-source voltage of the secondary rectifier (VDS_SR(MAX)). In the expression for NPS(MIN), ?VSPIKE should account for any additional voltage spike higher than VBULK(MAX)/NPS that occurs when QH is active and turns-off at non-zero current in AAM mode.
- Since the high-frequency transformer is usually a core-loss limited design instead of a saturation-limited design, the minimum duty cycle (DMIN) at VBULK(MAX) is more important. Lower DMIN increases core loss at VBULK(MAX), so this constraint creates another limitation on NPS(MIN).
- The winding loss distribution between the primary and secondary side of the transformer is the final consideration. As NPS increases, primary RMS current reduces, while secondary RMS current increases.
Equation 19. 
Equation 20. 
Equation 21. 