Frugal startup for PWM controller

A highly integrated voltage-mode PWM controller features an ultralow maximum startup current of 50uA, making it ideal for building high-voltage bias, offline or isolated DC/DC power supplies.

A highly integrated voltage-mode PWM controller features an ultralow maximum startup current of 50uA, making it ideal for building high-voltage bias, offline or isolated DC/DC power supplies.

The SC4911 can substantially ease design effort by being configured for flyback as well as forward and boost topologies.

It features a programmable switching frequency up to 500kHz and has the ability to dispense with optocouplers by using the auxiliary winding to give output feedback The SC4911 also features cycle by cycle current limiting, line and VCC undervoltage-lockout protection and preset maximum duty cycle of 65%.

A tiny space-saving MSOP 8 package and a wide operating temperature range of -40 to +125C when combined with the device's low cost and minimal external component count make the SC4911 a versatile and wise choice for high-volume power supplies in telecommunications, datacommunications and instrumentation equipment as well as battery chargers for cellular handsets and other portable equipment.

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