Question

Your group has been asked to design a portion of a power supply which reduces the variation due to

ripple from the rectifier stage. The completed power supply is intended to provide 300W of 48V DC

power to an RF transmitter. The transformer stage transforms a 3-phase AC power source at 60 Hz from

120 V RMS to 50V RMS, which is rectified before being applied to your circuit. You are designing the

regulator, not the rectifier.

The input to your circuit is guaranteed not to fall below 60V DC, but may vary as high has 65V DC. You

can perform this design with Zener diodes and ordinary diodes. The critical design parameters will be

selecting resistors and diodes which are rated for the currents/powers that will be present in the

system, and simulating the load regulation. I’m leaving the load regulation requirement unspecified, to

give you some room to play with different components. By that I mean, simulate the circuit to verify

there is at least some reduction of the ripple at the output, but your primary concern is that 300Ws at a

minimum of 48V can still make it to the load and none of your components exceed their limits.

Answer 1