DN05033/D - 12V, Off-line Power Supply With Primary Side Feedback Design Note
Reference Design using part NCP1251B by onsemi
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For End Products
- Electronic Meter
- Industrial Equipments
- Portable Instrumentation
- White Goods
Description
- DN05033/D, Design Note describes a very simple, low cost, primary side controlled, off-line flyback power supply using NCP1251B current mode controller (TSOP6 package) and an NDD04N60 D-Pak Mosfet. The design dispenses with the conventional TL431/optocoupler feedback scheme and uses primary side voltage sensing on the NCP1251 Vcc rail which is derived from an aux winding on the transformer. This scheme provides tight line regulation and a load regulation of +/- 5% which is more than adequate for most applications. The acceptable load regulation is achieved by tight coupling (bifilar wound) between the main 12V secondary and the 12V aux winding in the transformer. The voltage sensing circuit is comprised of Z2 and Q2. The zener voltage of Z2 plus the VBE drop of Q2 sets the nominal output voltage
Key Features
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Conversion TypeAC to DC
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Input Voltage90 to 267 (AC) V
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Output Voltage12 V
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Output Current2 A
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Output Power20 W
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Efficiency80 %
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TopologyFlyback- DCM
Featured Parts (2)
| Part Number | Manufacturer | Type | Description | |||
|---|---|---|---|---|---|---|
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NCP1251BSN65T1G | onsemi | AC to DC Switching Converters | AC to DC Switching Converter Flyback 9.4V 65kHz T/R 6-Pin TSOP | Buy | |
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NCP1251BSN100T1G | onsemi | AC to DC Switching Converters | AC to DC Switching Converter Flyback 9.4V 100kHz T/R 6-Pin TSOP | Buy | |