ZHCSIQ7B August 2018 – October 2024 UCC28950 , UCC28951
PRODUCTION DATA
- 1
- 1 特性
- 2 应用
- 3 说明
- 4 Pin Configuration and Functions
- 5 Specifications
-
6 Detailed Description
- 6.1 Overview
- 6.2 Functional Block Diagram
- 6.3
Feature Description
- 6.3.1 Start-Up Protection Logic
- 6.3.2 Voltage Reference (VREF)
- 6.3.3 Error Amplifier (EA+, EA–, COMP)
- 6.3.4 Soft-Start and Enable (SS/EN)
- 6.3.5 Light-Load Power Saving Features
- 6.3.6 Adaptive Delay, (Delay Between OUTA and OUTB, OUTC and OUTD (DELAB, DELCD, ADEL))
- 6.3.7 Adaptive Delay (Delay Between OUTA and OUTF, OUTB and OUTE (DELEF, ADELEF)
- 6.3.8 Minimum Pulse (TMIN)
- 6.3.9 Burst Mode
- 6.3.10 Switching Frequency Setting
- 6.3.11 Slope Compensation (RSUM)
- 6.3.12 Dynamic SR ON/OFF Control (DCM Mode)
- 6.3.13 Current Sensing (CS)
- 6.3.14 Cycle-by-Cycle Current Limit Current Protection and Hiccup Mode
- 6.3.15 Synchronization (SYNC)
- 6.3.16 Outputs (OUTA, OUTB, OUTC, OUTD, OUTE, OUTF)
- 6.3.17 Supply Voltage (VDD)
- 6.3.18 Ground (GND)
- 6.4 Device Functional Modes
-
7 Application and Implementation
- 7.1 Application Information
- 7.2
Typical Application
- 7.2.1 Design Requirements
- 7.2.2
Detailed Design Procedure
- 7.2.2.1 Power Loss Budget
- 7.2.2.2 Preliminary Transformer Calculations (T1)
- 7.2.2.3 QA, QB, QC, QD FET Selection
- 7.2.2.4 Selecting LS
- 7.2.2.5 Selecting Diodes DB and DC
- 7.2.2.6 Output Inductor Selection (LOUT)
- 7.2.2.7 Output Capacitance (COUT)
- 7.2.2.8 Select FETs QE and QF
- 7.2.2.9 Input Capacitance (CIN)
- 7.2.2.10 Current Sense Network (CT, RCS, R7, DA)
- 7.2.3 Application Curves
- 7.3 Power Supply Recommendations
- 7.4 Layout
- 8 Device and Documentation Support
- 9 Revision History
- 10Mechanical, Packaging, and Orderable Information
7.2.2.6 Output Inductor Selection (LOUT)
Inductor LOUT is designed for 20% inductor ripple current (∆ILOUT) calculated in Equation 60 and Equation 61:
Calculate output inductor RMS current (ILOUT_RMS) using Equation 62:
A 2µH inductor from Vitec Electronics Corporation, part number 75PR8108, is suitable for this design. The inductor has the following specifications:
The output inductor DC resistance is:
Estimate output inductor losses (PLOUT) using Equation 65 and recalculate the power budget using Equation 66. Note PLOUT is an estimate of inductor losses that is twice the copper loss. Note this may vary based on magnetic manufactures. It is advisable to double check the magnetic loss with the magnetic manufacture.
