Texas Instruments UCD8220, UCD8620 User's Manual and Specifications

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UCD8220, UCD8620

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SLUS652B–MARCH 2005–REVISED SEPTEMBER

DIGITALLY MANAGED PUSH-PULL ANALOG PWM CONTROLLERS

FEATURES 10-ns Typical Rise and Fall Times with 2.2-n F

For Digitally Managed Power Supplies Using 25-ns Input-to-Output Propagation Delay

µCs or the TMS320 DSP Family

25-ns Current Sense-to-Output Propagation

Voltage or Peak Current Mode Control with Delay

Cycle-by-Cycle Current Limiting

Programmable Current Limit Threshold

Clock input from Digital Controller to set

Digital Output Current Limit Flag

Operating Frequency and Max Duty Cycle

4.5-V to 15.5-V Supply Voltage Range

Analog PWM Comparator

Rated from -40°C to 105°C•

2-MHz Switching Frequency

110-V Input Startup Circuit and Thermal

APPLICATIONS

Shutdown (UCD8620)

Digitally Managed Switch Mode Power

Internal Programmable Slope Compensation Supplies

3.3-V, 10-m A Linear Regulator Push-Pull, Half-Bridge, or Full-Bridge

Converters•

DSP/µC Compatible Inputs

Battery Chargers•

Dual ±4-A True Drive™ High Current Drivers

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 microcontroller or the TMS320™ DSP family.

UCD8220 and UCD8620 are double-ended PWM controllers configured with push-pull drive logic. The UCD8620

has 110-V high-voltage startup circuit which can directly start up the controller from 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 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 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, True Drive, Power PAD are trademarks of Texas Instruments.

UNLESS OTHERWISE NOTED this document contains PRO- Copyright 2005, Texas Instruments Incorporated

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.