Zero-power standby PSR flyback controller for automotive

The UCC28730-Q1 isolated-flyback power

supply controller provides constant-voltage (CV) and constant-current (CC) output

regulation without the use of an optical coupler. A minimum switching frequency of

30 Hz achieves less than 5 mW of no-load power.

This device processes information from

the primary power switch and an auxiliary flyback winding for precise control of

output voltage and current.

An internal 700-V start-up switch,

dynamically- controlled operating states and a tailored modulation profile support

ultra-low stand-by power without sacrificing start-up time or output transient

response. Control algorithms in the UCC28730-Q1 allow operating efficiencies to meet

or exceed applicable standards. Discontinuous conduction mode (DCM) operation with

valley-switching reduces switching losses. Modulation of the switching frequency and

primary current peak amplitude (FM and AM) keeps the conversion efficiency high

across the entire load and line ranges.