| US 7,511,971 B2 | ||
| Constant voltage circuit for power adapter | ||
| Won Chun Lim, Kyungki-do (Korea, Republic of) | ||
| Assigned to Samsung Electro-Mechanics Co., Ltd., Suwon, Kyungki-Do (Korea, Republic of) | ||
| Filed on Aug. 10, 2006, as Appl. No. 11/463,737. | ||
| Claims priority of application No. 10-2005-0074450 (KR), filed on Aug. 12, 2005. | ||
| Prior Publication US 2007/0076456 A1, Apr. 05, 2007 | ||
| Int. Cl. H02M 3/335 (2006.01) | ||
| U.S. Cl. 363—16 [363/95] | 6 Claims |
| 1. A constant voltage circuit for a power adapter comprising:
a transformer having a primary coil and a secondary coil, the transformer transforming a primary voltage based on a pulse
width modulation (PWM) control into a secondary voltage according to a turn ratio of the primary and secondary coils;
a voltage detector for detecting an output voltage from the transformer;
a current detector for detecting output current which is supplied from the transformer to a load;
a current/voltage converter for converting the output current detected by the current detector into a current detection voltage
and outputting the converted current detection voltage to a detected voltage terminal of the voltage detector; and
a comparator for comparing a voltage of the output voltage detected by the voltage detector plus the current detection voltage
from the current/voltage converter with a predetermined reference voltage to output a difference voltage therebetween necessary
for the PWM control of the transformer.
|