Intended for power supplies with universal inputs (85 V to 265 V rms), the STR83145 latched, universal input-voltage switch incorporates timing, control, and drive circuitry with a high-current triac (bidirectional triode thyristor) switch. The device senses the applied ac line potential and automatically switches the rectifier and associated capacitors between a voltage-doubler configuration (for line voltages to 141 V) and a full-bridge configuration (for line voltages greater than 149 V). This eliminates the possibility of user error with adjustable jumpers or switches. Also, the related switch-mode power stage need operate only over a reduced range of dc input voltages when compared with "wide input" power supplies using a bridge rectifier only. The reduction in dc input voltage range permits the use of lower-voltage capacitors and leads to a reduction in power stage stresses and power dissipation.

FEATURES
■ Low Duty Cycle Triac Drive for Minimum Dissipation
■ For Universal Input Operation Between 85 V rms and 265 V rms to 10 A
■ Internal Latch Prevents False Mode Switching
■ Internal Sensitive-Gate Power Triac
■ Adjustable Start-Up Delay
■ Accurate 145 V rms Switch-Point Voltage
■ Low External Parts Count
■ Low Power Dissipation
■ Low-Power External Parts