Texas Instruments UCC3809EVM
The UCC3809EVM evaluation module is an isolated 10-W, 3.3-V converter designed for telecom input voltages, nominally -48 Vdc, but ranging from -32 Vdc to -75 Vdc. The UCC3809 economy primary-side controller is used as the pulse-width modulator (PWM), combined with a TLV431 low-voltage adjustable-precision shunt regulator on the secondary side. The nominal switching frequency for this converter is approximately 400 kHz. The UCC3809 is configured with a 50% duty-cycle clamp.