| 摘要 |
PURPOSE: A switching regulator control circuit is provided to improve regulating efficiency both at big loads and small loads. CONSTITUTION: A switching regulator control circuit includes a switching element electrically connected between a power supply and an output terminal, a reference voltage source(18) generating a reference voltage, an oscillating circuit(20), an error amplifier for outputting a difference between a voltage derived from dividing an output voltage of the output terminal and the reference voltage, a PWM(Pulse Width Modulation) control circuit(22), a PFM(Pulse Frequency Modulation) control circuit(21), and a switch driving circuit(123,124). The PWM control circuit includes an output of the error amplifier with an output of the oscillating circuit, modulates a pulse width, and outputs a control signal. The PFM control circuit compares an output of the error amplifier with an output of the oscillating circuit, modulates a pulse frequency and outputs a control signal. The switch driving circuit controls the switching element upon receiving the outputs of the PWM control circuit and the PFM control circuit. When switching element is controlled according to the output of the PWM control circuit, an on-resistance of the switching element is reduced.
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