| 摘要 |
PROBLEM TO BE SOLVED: To reduce current consumption of a switching regulator. SOLUTION: A first comparator 10 compares a feedback voltage Vfb corresponding to the output voltage Vout of a switching regulator 200 with a threshold voltage Vth having hysteresis, and outputs a voltage comparison signal Vcmp which is asserted when the feedback voltage Vfb is lower than the threshold voltage Vth. A second comparator 12 generates a current comparison signal Icmp which is asserted when the current IL flowing through a switching transistor M1 reaches a reference current Ic. If the current comparison signal Icmp is asserted during a period when the voltage comparison signal Vcmp is asserted, a logic unit 20 sets a control signal Spfm to a second level at which the switching transistor M1 is turned off, and sets the control signal Spfm to a first level at which the switching transistor M1 is turned on after the lapse of a predetermined off time Toff. COPYRIGHT: (C)2010,JPO&INPIT
|
