Other Parts Discussed in Thread: UC2855A, UC2855B,
Tool/software:
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 semiconductor 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.
From the analog product range, the UC2855A (and UC2855B) seems to be a good candidate for item 3. However, it has been around a long time (pre-2000), and its pricing would suggest that it is nearing end of life.
From the digital product range, the UCD3138 would seem to be capable of providing a solution, however, its capabilities seem far in excess of the requirements - we'd like a package with far fewer than 40 pins.
So, my question is: Are there any alternative products to the UCD3138 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?
Please note: this question is a continuation of a previous question:
