EPR-21 datasheet(24/32 Pages) POWERINT

Part #	EPR-21

Description	Engineering Prototype Report (EP-21) - 30 W DC-DC Converter with DPA424

PDF	32 Pages

Scroll/Zoom	100%

Manufacturer	POWERINT [Power Integrations, Inc.]

Direct Link	http://www.powerint.com

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24 / 32 page

EPR-21 – 5 V, 30 W DC-DC Converter

19-Nov-02

12.4 Output Ripple Measurements

12.4.1 Ripple Measurement Technique

For DC output ripple measurements, a modified oscilloscope test probe must be utilized

in order to reduce spurious signals due to pickup. Details of the probe modification are

provided in Figure 29 and Figure 30.

The 5125BA probe adapter is affixed with two capacitors tied in parallel across the probe

tip. The capacitors include one (1) 0.1

µF/50 V ceramic type and one (1) 1.0 µF/50 V

aluminum electrolytic. The aluminum electrolytic type capacitor is polarized, so proper

polarity across DC outputs must be maintained (see below).

Probe Ground

Probe Tip

Figure 29

− Oscilloscope Probe Prepared for Ripple Measurement.

(End Cap and Ground Lead Removed).

Figure 30

− Oscilloscope Probe with Probe Master 5125BA BNC Adapter.

(Modified with wires for probe ground for ripple measurement, and two

parallel decoupling capacitors added).

Page 24 of 32

Power Integrations, Inc.

Tel: +1 408 414 9660 Fax: +1 408 414 9760

EPR-21 Datasheet(PDF) 24 Page - Power Integrations, Inc.