TOP242R POWERINT [Power Integrations, Inc.], TOP242R Datasheet - Page 12

• Manufacturer Part Number: TOP242R
• Description: TOPSwitch -GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher
• Manufacturer: POWERINT [Power Integrations, Inc.]

Figure 11 for a description of the functions where the horizon-
tal axis (left hand side) represents the EXTERNAL CURRENT
LIMIT pin current. The meaning of the vertical axes varies
with function. For those that control the on/off states of the
output such as remote ON/OFF, the vertical axis represents the
enable/disable states of the output. For external current limit,
the vertical axis represents the magnitude of the I
see graphs in the typical performance characteristics section
for the current limit programming range and the selection of
appropriate resistor value.
MULTI-FUNCTION (M) Pin Operation (P and G Packages)
The LINE-SENSE and EXTERNAL CURRENT LIMIT pin
functions are combined to a single MULTI-FUNCTION pin
for P and G packages. The comparator with a 1 V threshold at
the LINE-SENSE pin is removed in this case as shown in
Figure 2b. All of the other functions are kept intact. However,
since some of the functions require opposite polarity of input
current (MULTI-FUNCTION pin), they are mutually
exclusive. For example, line sensing features cannot be used
simultaneously with external current limit setting. When
current is fed into the MULTI-FUNCTION pin, it works as a
voltage source of approximately 2.6 V up to a maximum
current of +400 µA (typical). At +400 µA, this pin turns into a
constant current sink. When current is drawn out of the MULTI-
FUNCTION pin, it works as a voltage source of
approximately 1.3 V up to a maximum current of –240 µA
(typical). At –240 µA, it turns into a constant current source.
Refer to Figure 12b.
There are a total of five functions available through the use of
the MULTI-FUNCTION pin: OV, UV, line feed forward with
DC
A short circuit between the MULTI-FUNCTION pin and
SOURCE pin disables all five functions and forces
Table 3. Typical MULTI-FUNCTION Pin Configurations.
12
*This table is only a partial list of many MULTI-FUNCTION pin configurations that are possible.
Three Terminal Operation
Under-Voltage
Overvoltage
Line Feed Forward (DC
Overload Power Limiting
External Current Limit
Remote ON/OFF
TOP242-250
MAX
Figure Number
reduction, external current limit and remote ON/OFF.
G
1/02
MAX
)
30
MULTI-FUNCTION PIN TABLE*
31
LIMIT
. Please
32
33
TOPSwitch-GX to operate in a simple three terminal mode like
TOPSwitch-II. The MULTI-FUNCTION pin is typically used
for line sensing by connecting a resistor from this pin to the
rectified DC high voltage bus to implement OV, UV and DC
reduction with line voltage. In this mode, the value of the
resistor determines the line OV/UV thresholds, and the DC
is reduced linearly with rectified DC high voltage starting from
just above the UV threshold. In high efficiency applications
this pin can be used in the external current limit mode instead,
to reduce the current limit externally to a value close to the
operating peak current, by connecting the pin to the SOURCE
pin through a resistor. The same pin can also be used as a
remote on/off and a synchronization input in both modes. Please
refer to Table 3 for possible combinations of the functions with
example circuits shown in Figure 30 through Figure 40. A
description of specific functions in terms of the MULTI-
FUNCTION pin I/V characteristic is shown in Figure 11. The
horizontal axis represents MULTI-FUNCTION pin current with
positive polarity indicating currents flowing into the pin. The
meaning of the vertical axes varies with functions. For those
that control the on/off states of the output such as UV, OV and
remote ON/OFF, the vertical axis represents the enable/
disable states of the output. UV triggers at I
typical) and OV triggers at I
hysteresis). Between the UV and OV thresholds, the output is
enabled. For external current limit and line feed forward with
DC
the I
lowers maximum duty cycle from 78% at I
typical) to 38% at I
available only with negative MULTI-FUNCTION pin current.
Please see graphs in the typical performance characteristics
section for the current limit programming range and the
selection of appropriate resistor value.
MAX
LIMIT
34
reduction, the vertical axis represents the magnitude of
and DC
35
MAX
. Line feed forward with DC
OV
36
(+225 µA). External current limit is
OV
37
(+225 µA typical with 30 µA
38
39
M(DC)
MAX
UV
reduction
(+50 µA
(+60 µA
40
MAX
MAX