Tool/software:
Dears
Customer design Dual-Phase buck, there have some question for circuit design
1. How to connect FB pin of secondary, Is it connected to the PFM/SYNC pin of primary?
2. How to chose value for CCOMP RCOMP CHF of EXTCOMP pin.
3. Why Dual-Phase topology FB connects Vout, but single-phase connection VDDA.
4. How to design PG/SYNCOUT pin circuit of secondary.
Hello
1.Yes, it is. Please refer the datasheet section 9.2.4 Design 4 – Dual-Phase 400-kHz 20-A Synchronous Buck Regulator
2.Use the Quick Start Calculator. Since the tool is designed for single-phase configuration, please make it sure to enter equivalent component values in the calculator
| Output Capacitor | Enter 2 x single-phase output capacitance |
| Inductor | Enter 0.5 x single-phase buck inductance |
| Current Sense Resistor | Enter 0.5 x single-phase current sense resistor value |
| Load Current | Enter 2 x single phase load current |
3. I think there is no special reason. It is just an example using external feedback.
4. Connect the PG pin (on the secondary side) to the system VDD (or MCU VDD) through 100kOhm pull up resistor.
-EL
