| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching regulator, along with its operation control method, capable of allowing the maximum switching frequency in VFM control mode to be equal to the switching frequency in PWM control mode with a simple circuit configuration, suppressing a ripple of output voltage and improving efficiency in VFM control mode. SOLUTION: There is provided an oscillation control circuit 13. When an error voltage opout becomes a second reference voltage Vr2 or higher and a second comparison signal CMPOUT becomes high level, the control circuit causes an enable signal OSCEN to be set at high level without delay. If the second comparison signal CMPOUT is at low level at the time when the clock signal CLK comes to low level from high level, the control circuit causes the enable signal OSCEN to be set at low level but if the second comparison signal CMPOUT is at high level, it keeps the enable signal OSCEN at high level continuously. COPYRIGHT: (C)2011,JPO&INPIT |
