| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC/DC converter control circuit, together with a DC/DC converter system, by which a power-saving mode with external control signal is realized with a small number of terminals for smaller size, resulting in an improved flexibility for mounting. SOLUTION: A resistor element RT and a switch part 1 are connected in series between a frequency setting terminal (RT) and a ground voltage, with an external control signal CTL inputted in the switch part 1. When the switch part 1 is turned off by the external control signal CTL, the connection to the ground voltage is opened while an oscillation drive part 4 does not operate, thus a power saving mode is kept. When the switch part 1 is turned on, the connection to the ground voltage is closed to trigger the oscillation drive part 4. A bias control part 5 is activated and a bias condition to the resistor element RT is controlled, thus oscillation frequency comes to a set value. The power- saving mode is controlled with no dedicated terminal to the external control signal CTL. COPYRIGHT: (C)2003,JPO
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