DPA423GN Power Integrations, DPA423GN Datasheet - Page 7

• Manufacturer Part Number: DPA423GN
• Description: IC CONV DC-DC DPA SWITCH 8SMD
• Manufacturer: Power Integrations
• Series: DPA-Switch®r

Specifications of DPA423GN

• Applications: Converter, Power Over Ethernet and Telecom Applications
• Voltage - Input: 16 ~ 75 V
• Number Of Outputs: 1
• Voltage - Output: 220V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SMD Gull Wing
• Output Voltage: 9 V
• Output Current: 1.75 A
• Input Voltage: - 0.3 V to + 220 V
• Switching Frequency: 282 KHz to 425 KHz
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• Duty Cycle (max): 79 %
• For Use With: 596-1195 - KIT REF DES DPA 6.6W DC-DC CONV596-1009 - KIT DESIGN ACCELERATOR DC-DC596-1007 - KIT DESIGN ACCELERATOR POE CONV
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 6. Synchronization Timing Diagram.
UV upper threshold has been reached again. Then, a soft-start
will be initiated the next time CONTROL pin voltage reaches
5.8.V. If the power supply loses regulation before reaching the
UV lower threshold, the device will enter auto-restart. At the end
of each auto-restart cycle (S7), the UV comparator is enabled. If
the UV upper threshold is not exceeded, the MOSFET will be
disabled during the next cycle (see Figure 5). The UV feature
can be disabled independent of OV feature.
Line Overvoltage Shutdown (OV)
The same resistor used for UV also sets an overvoltage
threshold which, once exceeded, will force the DPA-Switch
output into the off-state within one switching cycle. The ratio
of OV and UV thresholds is preset at 2.7 as can be seen in
Figure 7. When the MOSFET is off, the input voltage surge
capability is increased to the voltage rating of the MOSFET
(220 V), due to the absence of the reflected voltage and leakage
spikes on the drain. A small amount of hysteresis is provided on
the OV threshold to prevent noise triggering. The OV feature
can be disabled independent of the UV feature as shown in
Figure 13.
Line Feed-Forward with DC
The same resistor used for UV and OV also implements line
voltage feed-forward that minimizes output line ripple and
reduces power supply output sensitivity to line transients.
This feed-forward operation is illustrated in Figure 4 by the
different values of I
current, higher line voltage results in smaller operating duty
cycle. As an added feature, the maximum duty cycle DC
is also reduced from 75% (typical) at a voltage slightly higher
than the UV threshold to 33% (typical) at the OV threshold
(see Figures 4, 7). Limiting DC
helps prevent transformer saturation due to large load transients
in forward converter applications. DC
Oscillator
(SAW)
D
MAX
V
L
L
. Note that for the same CONTROL pin
2 V
0 V
MAX
MAX
Reduction
at higher line voltages
MAX
ON
of 33% at the OV
f
SYNC
≥ 128 kHz; t
MAX
OFF
OFF
≤ 7.7 µs; 120 ns ≤ t
threshold was chosen to ensure that the power capability of
the DPA-Switch is not restricted by this feature under normal
operation.
Remote ON/OFF
Remote ON/OFF control describes operation where the IC is
turned on or off for long periods as opposed to the cycle-by-
cycle on/off control, which is described in the Synchronization
section below.
DPA-Switch can be turned on or off by controlling the current into
the LINE-SENSE pin or out from the EXTERNAL CURRENT
LIMIT pin (see Figure 7). This allows easy implementation of
remote ON/OFF control of DPA-Switch in several different
ways. A transistor or an optocoupler output connected between
the EXTERNAL CURRENT LIMIT pin and the SOURCE pin
implements this function with “active-on” (Figures 17, 19 and 21)
while a transistor or an optocoupler output connected between
the LINE-SENSE pin and the CONTROL pin implements the
function with “active-off” (Figures 18, 20 and 22).
When a signal is received at the LINE-SENSE pin or the
EXTERNAL CURRENT LIMIT pin to disable the output
through any of the pin functions such as OV, UV and remote
ON/OFF, DPA-Switch always completes its current switching
cycle before the output is forced off. The internal oscillator is
stopped at the end of the current cycle and stays there as long
as the disable signal exists. When the signal at the above pins
changes state from disable to enable, the internal oscillator
starts the next switching cycle.
The remote ON/OFF feature can be used as a standby or power
switch to turn off the DPA-Switch and keep it in a very low
power consumption state for indefinitely long periods. If the
DPA-Switch is held in remote-off state for longer than 10 µs
t
ON
t
OFF
ON
≤ 2250 ns for f
≤ 3080 ns for f
SYNC
OSC
OSC
= 400 kHz
= 300 kHz
DPA423-426
Time
PI-2762-070501
7/05
P
7