This application note presents a low-cost high-voltage 100 mA non-isolated power supply using NCP1052 by buck and buck-boost topology. The NCP1052 is one of the latest low-cost switching controllers with integrated 700 V/ 300 mA power switch from ON Semiconductor. It is primarily designed for isolated 10 W-range flyback converter. If isolation is not needed, the IC can also be used as stepping-down buck and buck-boost converter for further cost saving by removing optocoupler and replacing the transformer by an inductor. The output current capability is 100 mA. The possible operating range is from input range between 20 Vdc and 700 Vdc to output range of 5.0 V or above with 100 mA. Typical efficiency around 65% is obtained in the 12 V buck demo board. Advantages of the proposed circuits include: • Comparing to flyback, buck and buck-boost eliminates optocoupler and replaces transformer by an inductor for cost saving. • Buck and buck-boost offers smaller voltage stress in switches comparing to flyback. It minimizes the switching loss and increases efficiency. • NCP105x can power up itself from the high input voltage with wide range between 20 Vdc and 700 Vdc. It needs no extra supply circuit. • NCP105x operates at 44, 100, or 136 kHz and accommodates various input voltages and currents.
This document presents application circuits for low-cost, high-voltage (20 Vdc to 700 Vdc) non-isolated power supplies using the NCP1052 switching controller. The NCP1052 is an integrated 700 V/300 mA power switch designed primarily for isolated flyback converters but can be used for buck and buck-boost topologies to eliminate the need for optocouplers and transformers. The circuits support an output current of 100 mA with an output voltage of 5.0 V or above, achieving typical efficiencies around 65%.
| Input Voltage Range | 20 Vdc to 700 Vdc |
|---|---|
| Output Voltage Range | 5.0 V or above |
| Output Current Capability | 100 mA |
| Integrated Switch Voltage | 700 V |
| Integrated Switch Current | 300 mA |
| Typical Efficiency | 65% |
| Switching Frequency | 44, 100, or 136 kHz |
It is primarily designed for isolated 10 W-range flyback converter applications.
Yes, it can be used as a stepping-down buck and buck-boost converter to save cost by removing the optocoupler and transformer.
The output current capability is 100 mA.
No, it can power up itself from the high input voltage with no extra supply circuit needed.