深圳市广辉电子有限公司

电源芯片STRW6765N、STR-W6765N、STRW6765、STR-W6765

Quasi-Resonant Topology
Primary Switching Regulators

准谐振软开关技术的拓扑结构
主要切换调整

Features and Benefits
▪ Quasi-resonant topology IC ⇒ Low EMI noise and soft
switching
▪ Bottom-skip operation ⇒ Improved system efficiency
over the entire output load by avoiding increase of
switching frequency
▪ Standby burst mode operation ⇒ Lowers input power at
very light output load condition
▪ Avalanche-guaranteed MOSFET ⇒ Improves systemlevel
reliability and does not require VDSS derating
▪ 800 V / 1.8 Ω, 52 to 110 W (Universal/230 Vac input)

Description
The STR-W6765 is a quasi-resonant topology IC designed for
SMPS applications. It shows lower EMI noise characteristics
than conventional PWM solutions, especially at greater than
2 MHz. It also provides a soft-switching operation to turn on the
internal MOSFET at close to zero voltage (VDS bottom point)
by use of the resonant characteristic of primary inductance
and a resonant capacitor.
The package is a fully molded TO-220, which contains the
controller chip (MIC) and MOSFET, enabling output power up
to 52 W with universal input or 110 W with a 230 Vac input.
The bottom-skip function skips the first bottom of VDS and turns
on the MOSFET at the second bottom point, to minimize an
increase of operational frequency at light output load, improving
system-level efficiency over the entire load range.
There are two standby functions available to reduce the input
power under very light load conditions. The first is an auto-burst
mode operation that is internally triggered by periodic sensing,
and the other is a manual standby mode, which is executed
by clamping the secondary output. In general applications,
the manual standby mode reduces the input power further
compared to the auto-burst mode.
The soft-start function minimizes surge voltage and reduces
power stress to the MOSFET and to the secondary rectifying