DER-120
22 W Triple Output Flyback – DPA424R
October 26, 2005
List Of Figures
Figure 1 – Populated Circuit Board (Top-side)..............................................................................4
Figure 2 – Schematic....................................................................................................................6
Figure 3 – Printed Circuit Layout...................................................................................................8
Figure 4 – Transformer Diagram.................................................................................................10
Figure 5 – Transformer Cross-Section........................................................................................11
Figure 6 – Line Regulation, Full Load .........................................................................................14
Figure 7 – Load Regulation, 28 V and 60 VDC Input..................................................................15
Figure 8 – 48 VDC, No Load.......................................................................................................16
Figure 9 – 48 VDC Input, Full Load.............................................................................................16
Figure 10 – 48 VDC, Minimum Load...........................................................................................16
Figure 11 – 60 VDC Input, Full Load...........................................................................................16
Figure 12 – Start-up Profile, 48 VDC No Load T: 10msec/div.....................................................17
Figure 13 – Start-up Profile, 48 VDC Full Load T: 10msec/div ...................................................17
Figure 14 – Transient Response Top: Load Current; 1 A/div. Bottom: +3.3 V Output 100 mV,
1ms/div. ...............................................................................................................................18
Figure 15 – Oscilloscope Probe Prepared for Ripple Measurement. (End Cap and Ground Lead
Removed) ............................................................................................................................19
Figure 16 – Oscilloscope Probe with Probe Master 5125BA BNC Adapter. (Modified with wires
for probe ground for ripple measurement, and two parallel decoupling capacitors added)..19
Figure 17 – +3.3 V Ripple, Full Load, 20mV/div; T: 2usec/div ....................................................20
Figure 18 – +9 V Ripple, Full Load, 50mV/div; T: 2usec/div .......................................................20
Figure 19 – +24 V Ripple, Full Load, 50mV/div; T: 2usec/div .....................................................20
Figure 20 – Gain-Phase Plot, 28VDC Input Maximum Steady State Load Vertical Scale: Gain =
8 dB/div, Phase = 40 °/div. Crossover Frequency = 4.55 kHz Phase Margin = 49.4°..........21
Figure 21 – Gain-Phase Plot, 48VDC Input Maximum Steady State Load Vertical Scale: Gain =
8 dB/div, Phase = 40 °/div. Crossover Frequency = 2.23 kHz Phase Margin = 63.7°..........21
Figure 22 – Gain-Phase Plot, 60 VDC Input Maximum Steady State Load Vertical Scale: Gain =
8 dB/div, Phase = 40 °/div. Crossover Frequency = 2.27 kHz Phase Margin = 76.7°..........22
Figure 23 – Gain-Phase Plot, 28 VDC Input Minimum Load Vertical Scale: Gain = 8 dB/div,
Phase = 40 °/div. Crossover Frequency = 4.97 kHz Phase Margin = 74.8°.........................22
Figure 24 – Gain-Phase Plot, 48 VDC Input Minimum Load Vertical Scale: Gain = 8 dB/div,
Phase = 40 °/div. Crossover Frequency = 1.28 kHz Phase Margin = 76.1°.........................23
Figure 25 – Gain-Phase Plot, 60 VDC Input Minimum Load Vertical Scale: Gain = 8 dB/div,
Phase = 40 °/div. Crossover Frequency = 896Hz Phase Margin = 53.98° ..........................23
Important Note:
This board is designed to be non-isolated. However the outputs are high voltage so please take
the necessary safety precautions.
Design Reports contain a power supply design specification, schematic, bill of materials, and
transformer documentation. Performance data and typical operation characteristics are
included. Typically only a single prototype has been built.
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