Switching regulator
Provided is a switching regulator configured to suppress noise coupling, which may occur when a comparator is switched between a normal current operation and a low current consumption operation, to thereby operate stably. The switching regulator has a configuration in which switches are connected to input terminals of the comparator, and a feedback resistor having a large resistance value is disconnected from the input terminal of the comparator when switching is performed between the normal current operation and the low current consumption operation.
1. A switching regulator, comprising:
a feedback resistor divider for outputting a feedback voltage representative of a voltage at an output terminal of the switching regulator;
a reference voltage circuit configured to generate a reference voltage;
a comparator, which includes a first input terminal connected to an output terminal of the feedback resistor divider, and a second input terminal connected to an output terminal of the reference voltage circuit, and which is configured to compare the feedback voltage and the reference voltage to each other;
a light load mode detecting circuit configured to detect a light load mode;
a first switch directly connected between the output terminal of the feedback resistor divider and the first input terminal of the comparator; and
a second switch directly connected between the first input terminal of the comparator and the second input terminal of the comparator,
the switching regulator being configured to control, based on a signal output from the comparator, a power FET connected between a voltage input terminal and the output terminal of the switching regulator, to thereby output a desired output voltage,
the first switch being turned off and the second switch being turned on when the comparator switches an operation current based on a detection signal from the light load mode detecting circuit indicating the light load mode.
2. The switching regulator according to claim 1 , wherein the light load mode detecting is configured to detect the light load mode based on a voltage at a coil connected to the output terminal of the switching regulator.
3. The switching regulator according to claim 1 , wherein the light load mode detecting circuit is configured to detect the light load mode based on a signal from an output terminal of the comparator.