| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a technique for detecting a failure in a feedback circuit while a switching power source is operating in a mode where an output is less than its adjusted value. <P>SOLUTION: A power source supplies a maximum electric power at a certain switching frequency, if there is no feedback signal while an output is less than its adjusted value. If no feedback signal is generated during period of failure time, an average output power is substantially reduced by a failure protective circuit. If no feedback signal is generated, a power source increases a maximum output power by raising a switching frequency and increasing an output to the adjusted value, before a failure time ends. If a feedback signal is generated when the output reaches the adjusted value, original switching frequency is recovered, the output returns to a non-adjusted value. If a feedback signal is generated when the failure time ends, the failure protective circuit performs substantial reduction of output power. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
