BSZ040N04LSG
Infineon
For this application a 40V, 40A, MOSFET BSZ040N04LSG from Infineon is selected as a secondary MOSFET.
Reference DesignAnalog
MAXREFDES1187: 7.5W 5V Offline Flyback Converter Using MAX17595
A 7.5W offline DCM flyback reference design providing a 5V/1.5A output from 176V-284V AC input using the MAX17595 controller and MAX17606 synchronous rectifier driver.
Overview
The MAXREFDES1187 is a detailed reference design for a 7.5W offline discontinuous conduction mode (DCM) flyback converter. The design uses the MAX17595 peak-current-mode controller to convert a 176V AC to 284V AC input into a regulated 5V DC output at up to 1.5A. It features a secondary-side MAX17606 synchronous rectifier driver and a specialized 750317622 transformer from Wurth Elektronik. Key technical features include a 125kHz switching frequency, programmable frequency dithering for EMI reduction, soft-start, and integrated protection such as hiccup-mode overcurrent and thermal shutdown. The document includes comprehensive design calculations for transformer magnetizing inductance, turns ratios, and peak/RMS current values.
Use Cases
- Universal input AC-DC power supplies
- Telecom power supplies (36V to 72V)
- Isolated industrial power modules
- EMI-sensitive power conversion
Topics
MAX17595
MAX17606
MAXREFDES1187
Flyback Converter
Offline Power Supply
DCM
Synchronous Rectification
750317622
AC-DC Converter
IPD80R2K4P7
Referenced Parts
IPD80R2K4P7
Infineon
For this application, the 800V 2.5A n-channel MOSFET IPD80R2K4P7 from Infineon® is selected as the primary MOSFET.
S1KL
Taiwan Semiconductor
An 800V, 1A diode S1KL from Taiwan Semiconductor is selected as the snubber diode for this design.
MAX17595
Analog Devices
The MAX17595 is a peak-current-mode controller for designing wide input-voltage flyback regulators.
MAX17606
Analog Devices
Here we are using synchronous rectification using the MAX17606 MOSFET driver at the secondary side.
TLV431BFTA
Diodes Incorporated
U3 is a low-voltage adjustable shunt regulator with a 1.24V reference voltage. In this design a 1.24V, 0.5% shunt regulator TLV431BFTA from Diodes Inc. is selected.
750317622
Wurth Elektronik
A customized transformer 750317622 from Würth Elektronik® is used in this design.
| BSZ040N04LSG | Infineon | For this application a 40V, 40A, MOSFET BSZ040N04LSG from Infineon is selected as a secondary MOSFET. |
| IPD80R2K4P7 | Infineon | For this application, the 800V 2.5A n-channel MOSFET IPD80R2K4P7 from Infineon® is selected as the primary MOSFET. |
| S1KL | Taiwan Semiconductor | An 800V, 1A diode S1KL from Taiwan Semiconductor is selected as the snubber diode for this design. |
| MAX17595 | Analog Devices | The MAX17595 is a peak-current-mode controller for designing wide input-voltage flyback regulators. |
| MAX17606 | Analog Devices | Here we are using synchronous rectification using the MAX17606 MOSFET driver at the secondary side. |
| TLV431BFTA | Diodes Incorporated | U3 is a low-voltage adjustable shunt regulator with a 1.24V reference voltage. In this design a 1.24V, 0.5% shunt regulator TLV431BFTA from Diodes Inc. is selected. |
| 750317622 | Wurth Elektronik | A customized transformer 750317622 from Würth Elektronik® is used in this design. |