ViewSonic VA502mb-1 Service Manual page 19

LD7552BPN (IC901): The LD7552B are low cost, low startup current, current
mode PWM controllers with green-mode power- saving operation. The integrated functions
include the leading-edge blanking of the current sensing, internal slope
compensation. They provide the users a superior AC/DC power application of higher efficiency,
low external component counts, and lower cost solution. Furthermore, LD7552B feature more
protections like OLP (Over Load Protection) and OVP (Over Voltage Protection) to eliminate the
external protection circuits. It is designed for the switching adaptor with 30W~60W output,
offered in both SOP-8 and DIP-8 package.
The function of each pin and the inside circuit diagram are as follows:
PIN Descriptions:
16
ViewSonic Corporation Confidential - Do Not Copy
VA502mb-1