Dear Sir/Madam,
we are designing a PFC input stage for a power converter. High efficiency, low power loss, and low EMI (low dv/dt, low di/dt) are all important requirements. We have identified a suitable power topology for this stage: Zero-Voltage-Transition (ZVT) boost, operating in CCM for most of the AC cycle for mid to high load power.
This topology requires the following components:
1. Two (2) controlled power switches: the main boost switch, and an auxiliary switch to control the current in the auxiliary path that sets up ZVT/ZCT for the main power switch (and the main power diode).
2. Passive and non-controlled components for the auxiliary current path: inductors, capacitors, diodes.
3. A control IC that can provide all the control and protection functions, and the gate drive to both the main switch, and the auxiliary switch.
The UC2855A (and UC2855B) from Unitrode (now TI) seems to be a good candidate for item 3.
So, my question is: Does ST have any alternative products that provide the same functionality as the UC2855A or UC2855B, in particular:
(1) The ability to shape the line current of a CCM PFC stage, and
(2) Implement ZVT?
