| 摘要 |
<P>PROBLEM TO BE SOLVED: To perform a stable, high speed and high efficiency constant voltage operation without requiring a complicated, large scale and high cost phase compensation circuit under a wide range of operating conditions. Ž<P>SOLUTION: The step-up/-down switching regulator is constituted of: a pair of step-down transistors M<SB>1</SB>, M<SB>2</SB>; a pair of step-up transistors M<SB>3</SB>, M<SB>4</SB>; an inductance coil 10; an output capacitor C<SB>o</SB>; and a control circuit 12. The control circuit 12 has the following parts for performing the PWM control of constant voltage for the step-down transistors M<SB>1</SB>, M<SB>2</SB>and the step-up transistors M<SB>3</SB>, M<SB>4</SB>: an output voltage feedback circuit 20, an inductor current sense circuit 22, a variable triangular wave generation circuit 24, switching control circuits 26, 28, a step-down driver circuit 16 and a step-up driver circuit 18. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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