SGLS384B
May 2008 – October 2024
UC2843A-Q1
PRODUCTION DATA
1
1
Features
2
Applications
3
Description
4
Pin Configuration and Functions
Pin Functions
5
Specifications
5.1
Absolute Maximum Ratings
5.2
ESD Ratings
5.3
Recommended Operating Conditions
5.4
Thermal Information
5.5
Electrical Characteristics
5.6
Typical Characteristics
6
Detailed Description
6.1
Overview
6.2
Functional Block Diagram
6.3
Feature Description
6.3.1
Pulse-by-Pulse Current Limiting
6.3.2
Current Sense Circuit
6.3.3
Error Amplifier Configuration
6.3.4
Undervoltage Lockout
6.3.5
Oscillator
6.4
Device Functional Modes
6.4.1
Normal Operation
6.4.2
Undervoltage Lockout (UVLO) Start-Up
6.4.3
UVLO Turnoff Mode
7
Application and Implementation
7.1
Application Information
7.2
Typical Application
8
Power Supply Recommendations
9
Layout
9.1
Layout Guidelines
10
Device and Documentation Support
10.1
Device Support
10.1.1
Development Support
10.1.1.1
Custom Design With WEBENCH® Tools
10.1.2
Device Nomenclature
10.2
Documentation Support
10.2.1
Related Documentation
10.3
Related Links
10.4
Receiving Notification of Documentation Updates
10.5
Support Resources
10.6
Trademarks
10.7
Electrostatic Discharge Caution
10.8
Glossary
11
Revision History
12
Mechanical, Packaging, and Orderable Information
10.1.2
Device Nomenclature
C
IN
Input bulk capacitance
C
OUT
Output capacitance
D
Duty cycle
ESR
Equivalent series resistance
G
BC
(f)
An estimate of the transfer function from the output of the opto-isolator to the PWM control voltage.
G
O
The DC gain of the control to output transfer function.
G
OPTO
(f)
The approximate transfer function across the opto-isolator in the design.
I
LPM
Transformer primary average current
I
LpPK
Peak transformer primary current
L
PM
Transformer primary magnetizing inductance
L
SM
Transformer secondary magnetizing inductance
N
PS
Primary to secondary transformer turns ratio
N
AS
Auxiliary to secondary transformer turns ratio
T
V
(f)
is the feedback control loop transfer function.
V
INripple
Input ripple voltage