Datasheet

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Auto-Track™ Function

How Auto-Track™ Works

PTH08000W

SLTS248B – JUNE 2005 – REVISED FEBRUARY 2008

Figure 13. Power-Up Response From Inhibit Control

The Auto-Track function is unique to the PTH/PTV family, and is available with all POLA products. Auto-Track

was designed to simplify the amount of circuitry required to make the output voltage from each module power up

and power down in sequence. The sequencing of two or more supply voltages during power up is a common

requirement for complex mixed-signal applications that use dual-voltage VLSI ICs such as the TMS320™ DSP

family, microprocessors, and ASICs.

Auto-Track works by forcing the module output voltage to follow a voltage presented at the Track control pin

(1)

This control range is limited to between 0 V and the module set-point voltage. Once the track-pin voltage is

raised above the set-point voltage, the module output remains at its set-point

(2)

. As an example, if the Track pin

of a 2.5-V regulator is at 1 V, the regulated output is 1 V. If the voltage at the Track pin rises to 3 V, the regulated

output does not go higher than 2.5 V.

When under Auto-Track control, the regulated output from the module follows the voltage at its Track pin on a

volt-for-volt basis. By connecting the Track pin of a number of these modules together, the output voltages follow

a common signal during power up and power down. The control signal can be an externally generated master

ramp waveform, or the output voltage from another power supply circuit

(3)

. For convenience, the Track input

incorporates an internal RC-charge circuit. This operates off the module input voltage to produce a suitable rising

waveform at power up.

Product Folder Link(s) :PTH08000W