45W / 24V Output Isolated Flyback Reference Design for Smart Speakers and Tubular MotorsOctober 30, 2019 by Paul Shepard
DER-815 is an engineering report and reference design from Power Integrations which describes a 45W isolated flyback ac-dc power supply that can deliver Constant Voltage (CV), Constant Current (CC) and Constant Power (CP) output. The power supply is designed to provide a 24V constant voltage output from 0A to 1.88A load current.
Constant current is programmed at 3A by the IS pin resistor providing 45W constant power output from 24 V to 15 V. The DER board is designed to operate at input voltage range from 90- to 265-Vac.
The Innoswitch3-CP device is a quasi-resonant flyback controller that combines the primary and secondary controllers along with the power MOSFET in a single low-profile surface mount off-line flyback switcher IC.
The secondary-side controller incorporates secondary-side synchronous rectifier drive. The device also includes an innovative inductive coupling feedback link (FluxLink™), which safely bridges the isolation barrier and eliminates the need for an optocoupler.
DER-815 offers an accurate CV/CP/CC regulation throughout the input range. The key design goals were high efficiency and compact size design.
Summary of Features
- 45W constant power output at 24V to 15V
- >91% average efficiency at nominal ac input
- <75mW no-load input power
- Low component count, 37 parts
- Integrated protection and reliability features
- Output short-circuit
- Line and output OVP
- Line surge or line overvoltage
- Over temperature shutdown
- Meets IEC 2.5kV ring wave, 2kV differential surge
- Meets EN55015 conducted EMI
The document contains the power supply specification, schematic, bill of materials, transformer documentation, printed circuit layout, design spreadsheet, and performance data.