RDK-252 Power Integrations, RDK-252 Datasheet - Page 20

• Manufacturer Part Number: RDK-252
• Description: KIT REF DESIGN DG CAPZERO
• Manufacturer: Power Integrations
• Series: CAPZero™r
• Type: Other Power Managementr

Specifications of RDK-252

• Main Purpose: Automatic X Capacitor Discharge
• Embedded: No
• Utilized Ic / Part: CAP014DG, CAP002DG, CAP012DG
• Primary Attributes: Low No-Load Input Power (
• Secondary Attributes: Surge Testing to EN6100-4-5 Class 4
• Input Voltage: 85 V to 264 V
• Board Size: 38.1 mm x 25.4 mm
• Product: Power Management Modules
• Dimensions: 38.1 mm x 25.4 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: CAP014DG
• Other names: 596-1313

Figure 25. Correct Power Meter Configurations for Accurate Measurement of Low Power / No-load and Higher Power Designs.
Rev. A 030910
No-load Input Power Settling Time
When measuring input power under no-load or standby conditions
ensure an adequate measurement time to allow the input power
to stabilize. Figure 27 shows the typical settling time for a
no-load input power measurement of a TOPSwitch-JX design at
230 VAC input. Input power measurements were taken using a
Yokogawa WT210 power meter every 100 ms for 5.5 minutes
(330 s). Note that a delay of >90 s is needed to obtain a power
measurement within 3 mW (5%) of the final value (55.4 mW).
No-load Input Power Repeatability
TOPSwitch-JX has minimal no-load input power and light load
efficiency variability which reduces the design margin needed to
meet a given specification. Figure 26 shows an example of
typical performance. Here the no-load of a single power supply
was measured with 48 TOP266EG parts at a device
temperature of both 25 °C and 100 °C. The total spread at a
single temperature was <5 mW and <7 mW including data from
both temperatures.
Figure 26. Example of Device to Device and Temperature Variation on No-load Input Power Measured in a Single Power Supply.
20
Application Note
V
(a) Low Power (<100 W) and No-load Power Input
Configuration (a) is Recommended for TOPSwitch-JX Power Levels.
IN
Power Measurements
V
Power Meter
2 MΩ
A
16 mΩ
PSU
Improving Light Load Efficiency and No-load Input Power
During light load and no-load conditions the consumption of the
feedback network, line sensing resistors and clamp are
significant and without optimization can double the no-load
input power of a design or significantly reduce available output
power under standby conditions.
The following approaches can be followed to minimize these
losses
•
•
•
•
•
•
•
However before trying these techniques first verify that the
power meter used to make input power measurements is
correctly configured (Figure 25).
Minimize output pre-loads
Connect line sense resistor to V pin
Clamp choice and optimization
Minimize bias winding voltage
Increase value of line sense resistance
Configure optocoupler transistor as part of Darlington pair
Use of TLV431 vs. TL431 secondary reference IC
V
IN
(b) High Power (>100 W)
A
16 mΩ
Power Meter
2 MΩ
V
www.powerint.com
PI-5848-030910
PSU
AN-47