STR-A6251 is a PWM-topology off-line secondary-feedback switching regulator IC that builds in a power MOSEFT with avalanche immunity and a current-mode control chip. The auto-burst mode operation (intermittent burst operation) and a control chip with low power consumption improve the overall system efficiency. Since only a few external components are required, this IC simplifies the system design with high performance and low cost.
●DIP-8 package without pin 6 is ideal for low profile small power supply system
●PWM operational frequency jittering The frequency jittering function suppresses EMI noise and
consequently reduces the EMI noise filter cost
The center frequency of PWM operation is set to 50 KHz,
and the frequency jittering provides variation of Δf= 5KHz
(typ), which is adjustable by the external capacitor.
●Over Load Protection (OLP) with a built-in timer (Auto restart)
Built-in delay timer circuit to trip the overload protection
requires no external OLP capacitor, which allows cost
reduction and space-saving.
●Over current protection (OCP) with constant current drooping
Constant output current drooping can be realized by simply
adding two external resistors.
Reduces stress of the built-in power MOSFET
●Auto burst standby operation
Reduces standby input power less than 100mW at no load
Normal operation = PWM mode
Standby operation = Intermittent burst mode
●Less transformer’s audible noise during the bust mode
●Built-in MOSFET guaranteeing avalanche energy
Simplifies the design of surge absorber, and requires no
derating of the breakdown voltage.
Thanks to the proprietary 900V BCD process, the built-in
startup circuit connected to the internal MOSFET drain
reduces both the discrete component count and the power
●Current Mode Feedback Control
●Leading Edge Blanking
Over current protection (OCP) ……… Pulse By Pulse
Over load protection (OLP) ………… Auto Restart
Over voltage protection (OVP) ……… Latch
Thermal shut down (TSD) ……………Latch
●Standby power supply
●Small power S.M.P.S