AS2916

SEMICONDUCTOR AS2916 PWM Controller Description The AS2916 is a dual, full featured, pulse width modulation controller. The second controller is intended to run the auxiliary supply. Both controllers share common oscillator and power up logic. Based on an improved AS3842, the AS2916 provides additional features that reduce component count and improve specifications in a wide range of power supply designs. The added functionality also includes bulk voltage sensing, overvoltage input and soft-start. The PWM function is controlled by the current sense comparator for normal current mode control and a second comparator for voltage mode soft-start. A buffered RAMP signal is available for slope compensation without loading the oscillator. The output stage is a high current totem pole output that sees only 140 ns delay from the PWM comparators. The AS2916 requires less than 25 µA of startup current. The undervoltage lockout (UVLO) thresholds are nominally 13.5 V for turn-on and 7.5 V for turn-off. The oscillator discharge current is trimmed to provide guaranteed duty cycle clamping. The AS2916 has a second low frequency oscillator, which frequency modulates the operating frequency of the PWM by 25%, thus reducing EMI emissions. Features Dual PWM Controller Ultra low start-up current, less than 25µA Main converter soft-start Frequency randomizer for improved EMI performance Bulk detect circuitry Remote ON/OFF control Buffered ramp for slope compensation Optio...