ZHCSKB9Q December 1999 – October 2019 UCC1895 , UCC2895 , UCC3895
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 Diagrams
- 7.3
Feature Description
- 7.3.1 ADS (Adaptive Delay Set)
- 7.3.2 CS (Current Sense)
- 7.3.3 CT (Oscillator Timing Capacitor)
- 7.3.4 DELAB and DELCD (Delay Programming Between Complementary Outputs)
- 7.3.5 EAOUT, EAP, and EAN (Error Amplifier)
- 7.3.6 OUTA, OUTB, OUTC, and OUTD (Output MOSFET Drivers)
- 7.3.7 PGND (Power Ground)
- 7.3.8 RAMP (Inverting Input of the PWM Comparator)
- 7.3.9 REF (Voltage Reference)
- 7.3.10 RT (Oscillator Timing Resistor)
- 7.3.11 GND (Analog Ground)
- 7.3.12 SS/DISB (Soft Start/Disable)
- 7.3.13 SYNC (Oscillator Synchronization)
- 7.3.14 VDD (Chip Supply)
- 7.4 Device Functional Modes
- 7.5 Programming
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Power Loss Budget
- 8.2.2.2 Preliminary Transformer Calculations (T1)
- 8.2.2.3 QA, QB, QC, QD FET Selection
- 8.2.2.4 Selecting LS
- 8.2.2.5 Selecting Diodes DB and DC
- 8.2.2.6 Output Inductor Selection (LOUT)
- 8.2.2.7 Output Capacitance (COUT)
- 8.2.2.8 Select Rectifier Diodes
- 8.2.2.9 Input Capacitance (CIN)
- 8.2.2.10 Current Sense Network (CT, RCS, RR, DA)
- 8.2.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文檔支持
- 12機(jī)械、封裝和可訂購信息
封裝選項(xiàng)
機(jī)械數(shù)據(jù) (封裝 | 引腳)
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
訂購信息
8.2.2.3 QA, QB, QC, QD FET Selection
In this design to meet efficiency and voltage requirements 20 A, 650 V, CoolMOS FETs from Infineon are chosen for QA..QD.
FET drain to source on resistance:
Equation 37. 
FET Specified COSS:
Equation 38. 
Voltage across drain-to-source (VdsQA) where COSS was measured, data sheet parameter:
Equation 39. 
Calculate average Coss [2]:
Equation 40. 
QA FET gate charge:
Equation 41. 
Voltage applied to FET gate to activate FET:
Equation 42. 
Calculate QA losses (PQA) based on Rds(on)QA and gate charge (QAg):
Equation 43. 
Recalculate power budget:
Equation 44. 