SYNC

ENABLE

ERROR

LDO

Regulator

Oscillator

800 kHz

Divide-by-2

Reset

Watchdog

Startup

PSU Thermal

Shutdown

Power

Stage

Input

Controller

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11

DCR010503, DCR012405, DCR010505

DCR011203, DCR011205, DCR012403

www.ti.com

SBVS013D – OCTOBER 2001 – REVISED JUNE 2016

Product Folder Links: DCR010503 DCR012405 DCR010505 DCR011203 DCR011205 DCR012403

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Copyright © 2001–2016, Texas Instruments Incorporated

8 Detailed Description

8.1 Overview

The DCR01 series of power modules offer isolation from a regulated power supply operating from a choice of

input voltages. The DCR01s provide a regulated 3.3-V or 5-V output voltage at a nominal output power of 1 W or

above. The DCR01 devices include a low dropout linear regulator internal to the device to achieve a well-

regulated output voltage. The DCR01 devices are specified for operational isolation only. The circuit design uses

an advanced BiCMOS/DMOS process.

8.2 Functional Block Diagram

8.3 Feature Description

8.3.1 Isolation

Underwriters Laboratories, UL™, defines several classes of isolation that are used in modern power supplies.

Safety extra low voltage (SELV) is defined by UL (UL1950 E199929) as a secondary circuit which is so

designated and protected that under normal and single fault conditions the voltage between any two accessible

parts, or between an accessible part and the equipment earthing terminal for operational isolation does not

8.3.1.1 Operation or Functional Isolation

The type of isolation used in the DCR01 products is referred to as operational or functional isolation. Insulated

wire used in the construction of the transformer acts as the primary isolation barrier. A high-potential (hipot), one-

second duration test (dielectric voltage, withstand test) is a production test used to verify that the isolation barrier

is functioning. Products with operational isolation must never be used as an element in a safety-isolation system.

8.3.1.2 Basic or Enhanced Isolation

Basic or enhanced isolation is defined by specified creepage and clearance limits between the primary and

secondary circuits of the power supply. Basic isolation is the use of an isolation barrier in addition to the insulated

wire in the construction of the transformer. Input and output circuits must also be physically separated by

specified distances.