Switching regulator and slope correcting circuit
View Patent ↗A switching regulator has an input terminal for receiving an input voltage, an output terminal for outputting an output voltage, a coil connected between the input terminal and the output terminal, and a slope correcting circuit for outputting a signal adapted to carry out slope correction for preventing current oscillation. An error amplifier compares one of the output voltage and a voltage division value of the output voltage with a reference voltage to output a signal, and a switch controls the output voltage with a signal generated using results obtained by arithmetically operating the output signal of the slope correcting circuit and the output signal of the error amplifier. The slope correcting circuit outputs a signal obtained by adjusting the signal adapted to carry out the slope correction in correspondence to the output voltage.
1. A switching regulator, comprising:
an input terminal through which an input voltage is inputted;
an output terminal through which an output voltage is outputted;
a coil connected between the input terminal and the output terminal;
a slope correcting circuit for outputting a signal adapted to carry out slope correction for preventing current oscillation;
an error amplifier for comparing one of the output voltage and a voltage division value of the output voltage with a reference voltage to output a signal; and
a switch for controlling the output voltage with a signal generated using results obtained by arithmetically operating the output signal of the slope correcting circuit and the output signal of the error amplifier,
wherein the slope correcting circuit outputs a signal obtained by adjusting the signal adapted to carry out the slope correction in correspondence to the output voltage.
2. A switching regulator according to claim 1 , wherein the slope correcting circuit outputs a signal which is adjusted such that an increasing rate or a decreasing rate of the signal adapted to carry out the slope correction is proportional to a decreasing rate of a current caused to flow through the coil.
3. A switching regulator according to claim 1 , wherein the slope correcting circuit outputs a signal which is adjusted such that an increasing rate or a decreasing rate of the signal adapted to carry out the slope correction is proportional to the reference voltage.
4. A slope correcting circuit for outputting a signal adapted to carry out slope correction for preventing current oscillation of a switching regulator, the slope correcting circuit comprising:
an operational amplifier for comparing a voltage division value of a power supply voltage with a reference voltage to output a signal;
a switch for receiving as its input the signal from the operational amplifier;
a mirror circuit connected in series with the switch between a power supply and a ground electric potential; and
a capacitor connected between the mirror circuit and the ground electric potential,
wherein the slope correcting circuit outputs a voltage developed across the capacitor and the mirror circuit as the signal adapted to carry out the slope correction.