| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC-DC converter for preventing through-current in the output transistor that constitutes an ideal diode, and malfunctions of the ideal diode. SOLUTION: A comparator 1 detects a current flowing in a choke coil L1 due to a voltage difference across both terminals of a second transistor T2, and outputs a detection signal Sa for turning off the second transistor T2, in response to the detected result. The second transistor T2 and the comparator 1 constitute the ideal diode ID. A through-current preventing pulse generating circuit 3 is provided, and generates a pulse signal, based on a signal Sb. The pulse signal Sd is generated so as to turn off the second transistor T2 for a duration, before and after timing for turning on a first transistor T1. A malfunction preventing circuit 4 maintains the off-state of the second transistor T2, until the signal Sb for turning on the first transistor T1 is inputted, after the comparator 1 detects a current, flowing from a load to the ground. COPYRIGHT: (C)2008,JPO&INPIT |
