LD7550-B

LD7550-B 12/22/2006 Green-Mode PWM Controller REV: 01a General Description The LD7550-B is a low cost, low startup current, current mode PWM controller with green-mode power-saving operation. The integrated functions such as the Features z z z z z z z z z z z High-Voltage CMOS Process with Excellent ESD protection Very Low Startup Current (<20µA) Under Voltage Lockout (UVLO) Current Mode Control with Cycle-by-Cycle Peak Current Limiting Leading-Edge Blanking on CS Pin Programmable Switching Frequency Internal Slope Compensation Proprietary Green-Mode Control for Power Saving Non-audible-noise Green Mode Control 300mA Driving Capability OVP (Over Voltage Protection) on Vcc Pin leading-edge blanking of the current sensing, internal slope compensation and the small SOT-26 package provide the users a high efficiency, low external component counts, and low cost solution for AC/DC power applications. Compared with LD7550, LD7550-B has different parameters or functions on the following characteristics --z Enlarger the hysteresis range of UVLO by lower down the UVLO(off) from 11.4V to 10V. z Add OVP (Over Voltage Protection) function on Vcc Pin. Applications z z z z Shorten the OCP delay time to 100nS to reduce the difference of OCP trip level under high line & low line. Switching AC/DC Adaptor and Battery Charger Open Frame Switching Power Supply 384X Replacement Typical Application AC input EMI Filter VCC UVLO 16.0V/ 10.0V OUT RT COMP LD7550-B OSC Control Logic ...