UCD8220 Datasheet, PDF (1/32 Pages) Texas Instruments – DIGITALLY MANAGED PUSH-PULL ANALOG PWM CONTROLLERS

UCD8220, UCD8620
www.ti.com
SLUS652B – MARCH 2005 – REVISED SEPTEMBER 2005
DIGITALLY MANAGED PUSH-PULL ANALOG PWM CONTROLLERS
FEATURES
• For Digitally Managed Power Supplies Using
µCs or the TMS320 ™ DSP Family
• Voltage or Peak Current Mode Control with
Cycle-by-Cycle Current Limiting
• Clock input from Digital Controller to set
Operating Frequency and Max Duty Cycle
• Analog PWM Comparator
• 2-MHz Switching Frequency
• 110-V Input Startup Circuit and Thermal
Shutdown (UCD8620)
• Internal Programmable Slope Compensation
• 3.3-V, 10-mA Linear Regulator
• DSP/µC Compatible Inputs
• Dual ±4-A TrueDrive™ High Current Drivers
• 10-ns Typical Rise and Fall Times with 2.2-nF
• 25-ns Input-to-Output Propagation Delay
• 25-ns Current Sense-to-Output Propagation
Delay
• Programmable Current Limit Threshold
• Digital Output Current Limit Flag
• 4.5-V to 15.5-V Supply Voltage Range
• Rated from -40°C to 105°C
APPLICATIONS
• Digitally Managed Switch Mode Power
Supplies
• Push-Pull, Half-Bridge, or Full-Bridge
Converters
• Battery Chargers
DESCRIPTION
The UCD8220 and UCD8620 are members of the UCD8K family of analog pulse-width modulator devices to be
used in digitally managed power supplies using a microcontroller or the TMS320™ DSP family.
UCD8220 and UCD8620 are double-ended PWM controllers configured with push-pull drive logic. The UCD8620
has a 110-V high-voltage startup circuit which can directly start up the controller from a 48-V telecom input line.
Systems using UCD8K devices close the PWM feedback loop with traditional analog methods, but the UCD8K
controllers include circuitry to interpret a time-domain digital pulse train. The pulse train contains the operating
frequency and maximum duty cycle limit which are used to control the power supply operation. This eases
implementation of a converter with high level control features without the added complexity or possible PWM
resolution limitations of closing the control loop in the discrete time domain.
Figure 1. UCD8220 Typical Simplified Push-Pull Converter Application Schematic
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
TMS320, TrueDrive, PowerPAD are trademarks of Texas Instruments.
UNLESS OTHERWISE NOTED this document contains PRO-
DUCTION DATA information current as of publication date. Prod-
ucts conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily
include testing of all parameters.
Copyright © 2005, Texas Instruments Incorporated