Patent ID: 8049523
Filing Date: 2011-11-01
Classification: G01S,H02J,H02M,H02S,Y02E

Abstract:
1. A circuit for sensing current flowing through an inductor, the circuit comprising: a cathode of a first diode connected to a first side of the inductor; a cathode of a second diode connected to a second side of the inductor; a first node connecting the anode of the first diode with the anode of the second diode; a first voltage divider with a first and second resistor connected between the first node and a power supply, wherein the connection between the first and second resistor forms a second node; a third resistor connected in series with a fourth resistor to form a second voltage divider; wherein the second voltage divider is connected between the power supply and the anode of a third diode; wherein the cathode of the third diode is connected to a ground; wherein the connection between the third and fourth resistor forms a third node; a capacitor connected between the ground and the third node; an operational amplifier with a non-inverting input connected to the third node and an inverting input connected to the second node; and a fifth resistor connected between the output of the amplifier and the second node; wherein power is supplied to the operational amplifier and substantially zero current is drawn from the inductor.