Converter device

Abstract

A converter for feeding a load via an inductor with a current having a controlled intensity between a maximum level and a minimum level may include: a switch switchable on and off to permit or prevent, respectively, feeding of current towards said inductor; first and second current sensors sensitive to the current flowing through said switch when said switch is on or off, respectively; comparator circuitry to identify if the current intensity detected by said first current sensor and said second current sensor reaches said maximum level and said minimum level, respectively, by generating respective logical signals; and drive circuitry for said switch sensitive to said logical signals and configured to turn off said switch when the current intensity detected by said first sensor reaches said maximum level and turning on said switch when the current intensity detected by said second current sensor reaches said minimum level.

What is claimed is: 
     
       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 switchable on and off to permit or prevent, respectively, feeding of current towards said inductor, 
 a first current sensor sensitive to the current flowing through said switch when said switch is on, 
 a second current sensor sensitive to the current flowing through said inductor when said switch is off, 
 comparator circuitry to identify if the current intensity detected by said first current sensor and said second current sensor reaches said maximum level and said minimum level, respectively, by generating respective logical signals, and 
 drive circuitry for said switch sensitive to said logical signals and configured to turn off said switch when the current intensity detected by said first sensor reaches said maximum level and turning on said switch when the current intensity detected by said second current sensor reaches said minimum level. 
 
     
     
       2. The converter of  claim 1 , wherein said switch is an electronic switch. 
     
     
       3. The converter of  claim 2 , wherein said electronic switch is a mosfet. 
     
     
       4. The converter of  claim 3 , wherein said mosfet is an N type mosfet. 
     
     
       5. The converter of  claim 1 , wherein said first sensor comprises a resistor traversed by the current flowing through said switch. 
     
     
       6. The converter of  claim 1 , wherein said second sensor includes a resistor coupled to the converter output, and a further switch is interposed between said switch and said resistor coupled to the converter output, said further switch conductive when said switch is turned off, whereby, with said switch turned off, said resistor coupled to the converter output is traversed by the current flowing through said inductor. 
     
     
       7. The converter of  claim 1 , further comprising a high level comparator coupled to said first current sensor and having an input coupled with a level shifter, to shift the level of an input signal to the converter representative of said maximum current level. 
     
     
       8. The converter of  claim 7 , wherein the level shifter is configured in the form of a voltage/current converter. 
     
     
       9. The converter of  claim 1 , further comprising a low level comparator coupled to said second current sensor having its output coupled with a pulse former, to generate as an output said respective logic level to feed to said drive circuitry. 
     
     
       10. The converter of  claim 9 , wherein the pulse former is configured in the form of a derivative network. 
     
     
       11. The converter of  claim 1 , further comprising:
 a logical circuit sensitive to said respective logical signals to generate at least one resulting logical output signal, 
 a drive circuit to generate, starting from said at least one resulting logical output signal, a drive signal for said switch. 
 
     
     
       12. The converter of  claim 11 , wherein said drive circuit includes:
 a pair of current generators alternatively activated by said at least one resulting logical output signal, to turn said switch on and off, respectively, and 
 a current amplifier or buffer driven by said current generators and in turn driving said switch. 
 
     
     
       13. The converter of  claim 12 , wherein said current generators drive said current amplifier or buffer via an intermediate amplifier which amplifies the current of one of said current generators. 
     
     
       14. Use of a converter to drive a load in the form of a light source, wherein the converter comprises:
 a switch switchable on and off to permit or prevent, respectively, feeding of current towards said inductor, 
 a first current sensor sensitive to the current flowing through said switch when said switch is on, 
 a second current sensor sensitive to the current flowing through said inductor when said switch is off, 
 comparator circuitry to identify if the current intensity detected by said first current sensor and said second current sensor reaches said maximum level and said minimum level, respectively, by generating respective logical signals, and 
 drive circuitry for said switch sensitive to said logical signals and configured to turn off said switch when the current intensity detected by said first sensor reaches said maximum level and turning on said switch when the current intensity detected by said second current sensor reaches said minimum level. 
 
     
     
       15. Use of a converter as claimed in  claim 14 , wherein the light source is a LED light source.