TOP244YN View Datasheet(PDF) - Power Integrations, Inc

Part Name

Description

Manufacturer

TOP244YN

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

Power Integrations, Inc 

TOP242-250

Function

TOPSwitch-FX

Light Load Operation Cycle skipping

Line Sensing/Exter-

nally Set Current

Limit (Y, R and F

Packages)

Line sensing and

externally set current

limit mutually

exclusive (M pin)

Current Limit

100% to 40%

Programming Range

P/G Package Current Identical to Y

Limits

package

Y/R/F Package

Current Limits

100% (R and F

package N/A*)

Thermal Shutdown

Maximum Duty Cycle

Reduction Threshold

125 °C min.

70 °C hysteresis

90 µA

Line Under-Voltage

Negative (turn-off)

Threshold

Soft-Start

N/A*

10 ms (duty cycle)

TOPSwitch-GX

TOPSwitch-GX

Advantages

Frequency and duty • Improves light load efficiency

cycle reduction

• Reduces no-load consumption

Line sensing and

• Additional design flexibility allows all

externally set current features to be used simultaneously

limit possible simul-

taneously (functions

split onto L and X pins

100% to 30%

• Minimizes transformer core size in highly

continuous designs

TOP243-246 P and

G packages internal

current limits reduced

• Matches device current limit to package

dissipation capability

• Allows more continuous design to lower

device dissipation (lower RMS currents)

90% (for equivalent

RDS(ON))

• Minimizes transformer core size

• Optomizes efficiency for most

applications

130 °C min.

75 °C hysteresis

• Allows higher output powers in high

ambient temperature applications

60 µA

• Reduces output line frequency ripple at

low line

• DCMAX reduction optimized for forward

design

40% of positive

(turn-on) threshold

• Provides a well defined turn-off threshold

as the line voltage falls

10 ms (duty cycle +

current limit)

• Gradually increasing current limit in

addition to duty cycle during soft-start

further reduces peak current and voltage

• Further reduces component stresses

during start up

Table 5. Comparison Between TOPSwitch-FX and TOPSwitch-GX. *Not available

TOPSwitch-FX vs. TOPSwitch-GX

Table 5 compares the features and performance differences

between TOPSwitch-GX and TOPSwitch-FX. Many of the new

features eliminate the need for additional discrete components.

Other features increase the robustness of design, allowing cost

savings in the transformer and other power components.

TOPSwitch-GX Design Considerations

Power Table

Data sheet power table (Table 1) represents the maximum

practical continuous output power based on the following

conditions: TOP242 to TOP246: 12 V output, Schottky output

diode, 150 V reflected voltage (VOR) and efficiency estimates

from curves contained in application note AN-29. TOP247

28 M

12/04

to TOP250: Higher output voltages, with a maximum output

current of 6 A.

For all devices, a 100 VDC minimum for 85-265 VAC and

250 VDC minimum for 230 VAC are assumed and sufficient

heat sinking to keep device temperature ≤100 °C. Power

levels shown in the power table for the R package device

assume 6.45 cm2 of 610 g/m2 copper heat sink area in an

enclosed adapter, or 19.4 cm2 in an open frame.

TOPSwitch-GX Selection

Selecting the optimum TOPSwitch-GX depends upon required

maximum output power, efficiency, heat sinking constraints

and cost goals. With the option to externally reduce current

limit, a larger TOPSwitch-GX may be used for lower power

applications where higher efficiency is needed or minimal heat

sinking is available.

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