| 摘要 |
A converter, for feeding a load via an inductor, includes a switch to permit or prevent the feeding of current towards inductor, and a current sensor with a resistor coupled to the converter output, adapted to sense the current through said inductor when switch is off. A further switch is provided which is conductive when said switch is turned off; moreover, a drive circuitry is provided which is coupled to current sensor to turn said switch on as a function of the detected current. Drive circuitry is fed by a bootstrap circuit which includes: a bootstrap capacitor to accumulate a feeding charge for drive circuitry and coupled to the converter output and to a bootstrap diode, a coupling capacitor interposed between said further switch and bootstrap diode, as well as a bootstrap resistor interposed between a power supply source and bootstrap diode to charge coupling capacitor therefrom. |
| 主权项 |
1. A converter for feeding a load via an inductor with a current having a controlled intensity between a maximum level and a minimum level, the converter comprising:
a switch switcheable on and off to permit or prevent, respectively, feeding of current towards said inductor, a current sensor including a resistor coupled to the converter output and sensitive to the current flowing through said inductor when said switch is off, a further switch interposed between said switch and said resistor; said further switch being conductive when said switch is turned off, whereby, with said switch turned off, said resistor coupled to the converter output is traversed by current flowing through said inductor, and drive circuitry of said switch coupled to said current sensor to turn said switch on as a function if the current detected by said current sensor, wherein a bootstrap circuit is provided for feeding said drive circuitry, said bootstrap circuit comprising: a bootstrap capacitor to accumulate a feeding charge for said drive circuitry, wherein said bootstrap capacitor is coupled to the converter output and a bootstrap diode, a coupling capacitor interposed between said further switch and said bootstrap diode; a bootstrap resistor interposed between a power supply source and said bootstrap diode to charge said coupling capacitor from said power supply source, whereby, with said switch turned off, said bootstrap diode transfers charge from said coupling capacitor to said bootstrap capacitor and said resistor coupled to the converter output is traversed by the current flowing through said inductor. |
