| CPC H02M 3/158 (2013.01) [H02M 1/0009 (2021.05)] | 15 Claims |
|
1. An open-loop inductor current emulating circuit, which is applicable to a power converter, wherein the power converter includes a driver circuit, a high-side switch, a low-side switch, an inductor and an output capacitor, an output terminal of the driver circuit is connected to a control terminal of the high-side switch and a control terminal of the low-side switch, a first terminal of the high-side switch is coupled to an input voltage, a second terminal of the high-side switch is connected to a first terminal of the low-side switch, a second terminal of the low-side switch is grounded, a node between the second terminal of the high-side switch and the first terminal of the low-side switch is connected to a first terminal of the inductor, a second terminal of the inductor is connected to a first terminal of the output capacitor, and a second terminal of the output capacitor is grounded, the open-loop inductor current emulating circuit comprising:
a current sensor circuit connected to the first terminal of the low-side switch and configured to sense a current flowing through the first terminal of the low-side switch to output a current sensed signal, wherein a plurality of waveform segments of a plurality of waveforms of the current sensed signal includes a plurality of rising waveform segments and a plurality of falling waveform segments;
an emulation controller circuit connected to the current sensor circuit, wherein the emulation controller circuit is configured to output a plurality of charging current signals respectively according to a plurality of currents on the plurality of rising waveform segments of the current sensed signal, and the emulation controller circuit is configured to output a plurality of discharging current signals respectively according to a plurality of currents of the plurality of falling waveform segments of the current sensed signal;
a charging and discharging circuit connected to the emulation controller circuit and a first terminal of a capacitor, wherein a second terminal of the capacitor is grounded, the charging and discharging circuit is configured to generate a plurality of charging currents respectively according to the plurality of charging current signals, the charging and discharging circuit is configured to generate a plurality of discharging currents respectively according to the plurality of discharging current signals, the charging and discharging circuit is configured to alternatively output the plurality of charging current signals and the plurality of discharging currents to the capacitor to charge and discharge the capacitor multiple times, and a current signal of the capacitor that is charged and discharged multiple times is an emulated voltage signal of an inductor current of the inductor; and
an initial control circuit connected to the emulation controller circuit and the first terminal of the capacitor, wherein the emulation controller circuit generates an initial signal according to a valley current of the current sensed signal, and the initial control circuit transits the initial signal from the emulation controller circuit to the capacitor to pull down a voltage of a voltage signal of the capacitor to a valley voltage.
|