STMICROELECTRONICS STEVAL-L6983IV1 Evaluation Board, L6983I, Synchronous Iso-Buck Converter

STEVAL-L6983IV1 is a synchronous iso-buck converter evaluation board based on L6983I designed for isolated applications. The primary output voltage can be accurately adjusted, whereas isolated secondary output is derived by using a given transformer ratio. No optocoupler is required. The primary sink capability up to -4.5A (even during soft-start) allows a proper energy transfer to secondary side as well as enables a tracked soft-start of secondary output. The control loop is based on a peak current mode architecture and the device operates in forced PWM. The 390ns blanking time filters oscillations, generated by the transformer leakage inductance, making the solution more robust. The switching frequency can be programmed in 200kHz - 1MHz range with optional spread spectrum for improved EMC. The EN pin provides enable/disable functionality. The typ shutdown current is 2µA when disabled. As soon as EN pin is pulled-up device is enabled, internal 1.3ms soft start takes place.

• Designed for iso-buck topology
• Input voltage range 4 to 38V and up to 10W deliverable power (depending on application conditions)
• Isolated output voltage unregulated
• Optional post regulation (not mounted, layout foreseen at the bottom)
• Embeds the transformer
• Regulation at the primary side, no optocoupler required
• 200kHz to 1MHz programmable switching frequency
• Suitable for external synchronization
• Power-good signal available and input EMI filter embedded
• Selectable spread spectrum function for improved EMC performance