| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power device which suppresses output voltage ripples and intermittent sounds, in a circuit for performing a changeover of a burst mode and continuous oscillation, and has improved high efficiency when the device is at standby. SOLUTION: When a standby signal is inputted to a standby changeover signal outputting means 111, while the power device operates in a first operation mode (normal operation mode), it is changed over to a second operation mode (standby mode). The output of an on-width controlling comparator 120 is prevented from being outputted to an RS flip-flop 102 for on/off operation, a standby mode current limiting comparator 106 outputs a signal to an RS flip-flop 118 for on/off operation, and a changeover is performed to determine off-timing. Besides, the flip-flop 118 for the on/off operation is kept in a reset state and oscillation is stopped, when the voltage of (d) terminal becomes the voltage of a constant voltage source 116 or lower. Reset of the flip-flop 118 for on/off operation is released and oscillation is started, when it becomes the voltage of a constant voltage source 114 or higher. Burst mode operation is performed by repeating these operations.
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