| 摘要 |
PROBLEM TO BE SOLVED: To obtain a constant current control type switching regulator for converting an input voltage into a desired output voltage and outputting the converted voltage, which can eliminate the necessity of a resistor for current detection, reduce the number of parts, and reduce loss caused by a current applied to the resistor. SOLUTION: In the regulator, a current sensing circuit 2 detects a current applied during a switching transistor M1 is on and converts the detected current into a voltage to generate a current sensing voltage VSNS, an averaging circuit 3 averages the current sensing voltage VSNS to generate an output voltage VINT, and the operations of the switching transistor M1 and a synchronous rectifying transistor M2 in PWM control are each controlled based on a clock signal CLK from an oscillation circuit 6 used as a reference of a frame in PWM control and a signal CPOUT as a signal indicating a result of comparison in voltages between the output voltage VINT of the averaging circuit 3 and a first reference voltage VREF1. COPYRIGHT: (C)2009,JPO&INPIT
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