PFS7323-7329
120
110
120
110
230 VAC
135 VAC
180 VAC
Expected Frequency
V
IN = 115 VAC
100% Peak Load
75% Peak Load
Range at Peak
Rated Load
90 VAC
100
90
100
90
115 VAC
80
80
70
70
50% Peak Load
25% Peak Load
60
50
60
50
40
30
20
10
40
30
20
10
Peak Load
0
45
90
135
180
0
45
90
135
180
Line Conduction Angle (°)
Line Conduction Angle (°)
Figure 9. (a) Frequency Variation Over Line Half-Cycle as a Function of Input Voltage (b) Frequency Variation Over Line Half-Cycle as a Function of Load.
~5 V
~5 V
VIN < ~140 VAC
~1.25 V
VIN > ~170 VAC
~1.25 V
~0.8 V
~5 V
~140 VAC
~170 VAC
(Full Power)
VE
VIN
PI-6864-050313
Figure 10. VOFF vs. VE and VOFF vs. Input Voltage.
and FEEDBACK pins are satisfied and the sensed VOLTAGE
MONITOR pin current is above IUV+ ,the IC applies a ~6 mA
current sink through the VOLTAGE MONITOR pin and checks
that the status of the REFERENCE pin voltage is still in a valid
range. This checks to ensure that the FEEDBACK and
REFERENCE pins are not shorted together. In the event that
these pin voltage are shorted or the REFERENCE pin current is
no longer in the valid range, VOLTAGE MONITOR pin holds the
6 mA current sink indefinitely until the REFERENCE pin is in the
valid range. Figure 8 illustrates this sequence.
Figure 9a shows the typical half-line frequency profile of the
device switching frequency as a function of input voltage at
peak load conditions. Figure 9b shows for a given line
condition the effect of EcoSmart™ to the switching frequency
as a function of load. The switching frequency is not a function
of boost choke inductance in CCM (continuous conduction
mode) operation.
EcoSmart
The HiperPFS-2 includes an EcoSmart mode wherein the
internal error signal (VE) is used to detect the converter output
power. Since the internal error-signal is proportional to the
output power, this signal level is used to set the average
switching frequency as a function of output power. The off-time
integrator control reference (VOFF) is controlled with respect to
the internal error-voltage level (output power) to allow the
converter to maintain output voltage regulation and relatively flat
conversion efficiency between 20% to 100% of rated load
Timing Supervisor and Operating Frequency Range
Since the controller is expected to operate with a variable
switching frequency over the line frequency half-cycle, typically
spanning a range of 24 – 110 kHz, the controller also features a
timing supervisor function which monitors and limits the
maximum switch on-time and off-time as well as ensures a
minimum cycle off-time.
7
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Rev. B 06/13
POWERINT [ Power Integrations ]
