Datasheet

DCV01 Series

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SBVS014A –AUGUST 2000–REVISED DECEMBER 2013

FUNCTIONAL DESCRIPTION

OVERVIEW

The DCV01 offers up to 1 W of unregulated output power with a typical efficiency of up to 85%. This is achieved

through highly integrated packaging technology and the implementation of a custom power stage and control IC.

The circuit design uses an advanced BiCMOS/DMOS process. Separate primary and secondary transformer

windings give good isolation and low barrier capacitance.

POWER STAGE

This uses a push-pull, center-tapped topology switching at 400 kHz (divide-by-2 from 800-kHz oscillator).

OSCILLATOR AND WATCHDOG

The onboard 800-kHz oscillator generates the switching frequency via a divide-by-2 circuit. The oscillator can be

synchronized to other DCV01 circuits or an external source, and is used to minimize system noise. A watchdog

circuit checks the operation of the oscillator circuit. The oscillator can be stopped by pulling the SYNC

pin low.

The output pins will be tri-stated. This will occur in 2 μs.

THERMAL SHUTDOWN

The DCV01 is protected by a thermal-shutdown circuit. If the on-chip temperature exceeds 150°C, the device will

shut down. Once the temperature falls below 150°C, normal operation will resume.

SYNCHRONIZATION

In the event that more than one dc-dc converter is needed onboard, beat frequencies and other electrical

interference can be generated. This is due to the small variations in switching frequencies between the dc-dc

converters.

The DCV01 overcomes this by allowing devices to be synchronized to one another. Up to eight devices can be

synchronized by connecting the SYNC

pins together, taking care to minimize the capacitance of tracking. Stray

capacitance (> 3 pF) will have the effect of reducing the switching frequency, or even stopping the oscillator

circuit.

It should be noted that if synchronized devices are used at start up, all devices will draw maximum current

simultaneously. This can cause the input voltage to dip, and if it dips below the minimum input voltage (4.5 V),

the devices may not start up. A 2.2-μF capacitor should be connected close to the input pins. If more than eight

devices are to be synchronized, it is recommended that the SYNC

pins are driven by an external device.

Details are contained in Application Report SBAA035, External Synchronization of the DCP01/02 Series of

DC/DC Converters, available for download from www.ti.com.

CONSTRUCTION

The basic construction of the DCV01 is the same as standard ICs. There is no substrate within the molded

package. The DCV01 is constructed using an IC, rectifier diodes, and a wound magnetic toroid on a leadframe.

Since there is no solder within the package, the DCV01 does not require any special printed circuit board (PCB)

assembly processing. This results in an isolated dc-dc converter with inherently high reliability.