TOP258PN Power Integrations, TOP258PN Datasheet - Page 9

IC OFFLINE SWIT PROG OVP 8DIP

TOP258PN

Manufacturer Part Number
TOP258PN
Description
IC OFFLINE SWIT PROG OVP 8DIP
Manufacturer
Power Integrations
Series
TOPSwitch®-HXr
Type
Off Line Switcherr
Datasheet

Specifications of TOP258PN

Output Isolation
Isolated
Frequency Range
119 ~ 145kHz
Voltage - Output
700V
Power (watts)
77W
Operating Temperature
-40°C ~ 150°C
Package / Case
8-DIP (0.300", 7.62mm), 7 Leads
Output Voltage
700 V
Input / Supply Voltage (max)
9 V
Input / Supply Voltage (min)
- 0.3 V
Duty Cycle (max)
78 %
Switching Frequency
132 KHz
Operating Temperature Range
- 40 C to + 150 C
Mounting Style
SMD/SMT
Maximum Operating Temperature
+ 150 C
Minimum Operating Temperature
- 40 C
Output Current
6.88 A
Output Power
48 W
For Use With
596-1193 - KIT REF DESIGN TOP HX FOR TOP258
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
596-1189-5
(half frequency), which may be preferable in some cases such
as noise sensitive video applications or a high effi ciency
standby mode. Otherwise, the FREQUENCY pin should be
connected to the SOURCE pin for the default 132 kHz. In the
M, P and G packages and the TOP259-261 Y package option,
the full frequency PWM mode is set at 66 kHz, for higher
effi ciency and increased output power in all applications.
To further reduce the EMI level, the switching frequency in the
full frequency PWM mode is jittered (frequency modulated) by
approximately ±2.5 kHz for 66 kHz operation or ±5 kHz for
132 kHz operation at a 250 Hz (typical) rate as shown in
Figure 10. The jitter is turned off gradually as the system is
entering the variable frequency mode with a fi xed peak drain
current.
Pulse Width Modulator
The pulse width modulator implements multi-mode control by
driving the output MOSFET with a duty cycle inversely
proportional to the current into the CONTROL pin that is in
excess of the internal supply current of the chip (see Figure 9).
The feedback error signal, in the form of the excess current, is
fi ltered by an RC network with a typical corner frequency of
7 kHz to reduce the effect of switching noise in the chip supply
current generated by the MOSFET gate driver.
To optimize power supply effi ciency, four different control
modes are implemented. At maximum load, the modulator
operates in full frequency PWM mode; as load decreases, the
modulator automatically transitions, fi rst to variable frequency
PWM mode, then to low frequency PWM mode. At light load,
the control operation switches from PWM control to multi-cycle-
modulation control, and the modulator operates in multi-cycle-
modulation mode. Although different modes operate differently
to make transitions between modes smooth, the simple
relationship between duty cycle and excess CONTROL pin
current shown in Figure 9 is maintained through all three PWM
modes. Please see the following sections for the details of the
operation of each mode and the transitions between modes.
Full Frequency PWM mode: The PWM modulator enters full
frequency PWM mode when the CONTROL pin current (I
reaches I
kept constant at f
TOP259-261 Y, pin selectable 132 kHz or 66 kHz for Y and E/L
www.powerint.com
Figure 10. Switching Frequency Jitter (Idealized V
Frequency
V
Switching
DRAIN
B
. In this mode, the average switching frequency is
OSC
f
OSC
f
OSC
(66 kHz for P, G and M packages and
-
+
4 ms
DRAIN
Waveforms).
Time
C
)
packages). Duty cycle is reduced from DC
reduction of the on-time when I
operation is identical to the PWM control of all other TOPSwitch
families. TOPSwitch-HX only operates in this mode if the cycle-
by-cycle peak drain current stays above k
where k
externally set via the X or M pin.
Variable Frequency PWM mode: When peak drain current is
lowered to k
reduction, the PWM modulator initiates the transition to variable
frequency PWM mode, and gradually turns off frequency jitter.
In this mode, peak drain current is held constant at k
I
frequency of f
frequency of f
accomplished by extending the off-time.
Low Frequency PWM mode: When switching frequency
reaches f
transition to low frequency mode. In this mode, switching
frequency is held constant at f
similar to the full frequency PWM mode, through the reduction
of the on-time. Peak drain current decreases from the initial
value of k
k
the current limit externally set via the X or M pin.
Multi-Cycle-Modulation mode: When peak drain current is
lowered to k
cycle-modulation mode. In this mode, at each turn-on, the
modulator enables output switching for a period of T
the switching frequency of f
30 kHz) with the peak drain current of k
stays off until the CONTROL pin current falls below I
mode of operation not only keeps peak drain current low but
also minimizes harmonic frequencies between 6 kHz and
30 kHz. By avoiding transformer resonant frequency this way,
all potential transformer audible noises are greatly supressed.
Maximum Duty Cycle
The maximum duty cycle, DC
value of 78% (typical). However, by connecting the VOLTAGE-
MONITOR or MULTI-FUNCTION pin (depending on the
package) to the rectifi ed DC high voltage bus through a resistor
with appropriate value (4 MΩ typical), the maximum duty cycle
can be made to decrease from 78% to 40% (typical) when input
line voltage increases from 88 V to 380 V, with dual gain slopes.
Error Amplifi er
The shunt regulator can also perform the function of an error
amplifi er in primary side feedback applications. The shunt
regulator voltage is accurately derived from a temperature-
compensated bandgap reference. The CONTROL pin dynamic
impedance Z
CONTROL pin clamps external circuit signals to the V
level. The CONTROL pin current in excess of the supply
current is separated by the shunt regulator and becomes the
feedback current I
LIMIT
PS(LOWER)
(set) while switching frequency drops from the initial full
PS(UPPER)
*I
MCM(MIN)
PS(UPPER)
LIMIT
PS(UPPER)
PS(LOWER)
(set), where k
C
MCM(MIN)
OSC
sets the gain of the error amplifi er. The
is 55% (typical) and I
(30 kHz typical), the PWM modulator starts to
* I
(132 kHz or 66 kHz) towards the minimum
LIMIT
fb
* I
*I
for the pulse width modulator.
(30 kHz typical). Duty cycle reduction is
LIMIT
LIMIT
(set) towards the minimum value of
(set), the modulator transitions to multi-
(set) as a result of power supply load
PS(LOWER)
MCM(MIN)
MAX
MCM(MIN)
C
, is set at a default maximum
is increased beyond I
is 25% (typical) and I
TOP252-262
(4 or 5 consecutive pulses at
LIMIT
and duty cycle is reduced,
(set) is the current limit
PS(LOWER)
PS(UPPER)
MAX
through the
*I
LIMIT
*I
LIMIT
(set), and
C(OFF)
MCM(MIN)
PS(UPPER)
(set),
C
B
LIMIT
. This
voltage
. This
Rev. F 01/09
(set) is
*
at
9

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