TOP245F datasheet(10/52 Pages) POWERINT

Teilenummer	TOP245F

Bauteilbeschribung	TOPSwitch -GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher

PDF	52 Pages

Scroll/Zoom	100%

Hersteller	POWERINT [Power Integrations, Inc.]

Direct Link	http://www.powerint.com

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10 / 52 page

TOP242-250

1/02

is also used to generate a temperature-compensated current

reference which is trimmed to accurately set the switching

frequency, MOSFET gate drive current, current limit, and the

line OV/UV thresholds. TOPSwitch-GX has improved circuitry

to maintain all of the above critical parameters within very tight

absolute and temperature tolerances.

High-Voltage Bias Current Source

This current source biases TOPSwitch-GX from the DRAIN

pin and charges the CONTROL pin external capacitance

during start-up or hysteretic operation. Hysteretic operation

occurs during auto-restart, remote off and over-temperature

shutdown. In this mode of operation, the current source is

switched on and off with an effective duty cycle of approxi-

mately 35%. This duty cycle is determined by the ratio of

CONTROL pin charge (I

C) and discharge currents (ICD1 and

CD2).

This current source is turned off during normal

operation when the output MOSFET is switching. The effect

of the current source switching will be seen on the DRAIN

voltage waveform as small disturbances and is normal.

TOP245F Datenblatt(PDF) 10 Page - Power Integrations, Inc.