US Patent No. 10,560,990

LIGHT EMITTING DIODE CIRCUIT WITH ACCURATE CURRENT MONITORING OF TWO OR MORE DIFFERENT LED STRINGS


Patent No. 10,560,990
Issue Date February 11, 2020
Title Light Emitting Diode Circuit With Accurate Current Monitoring Of Two Or More Different Led Strings
Inventorship Fabio Fragiacomo, Montegrotto Terme (IT)
Paolo Milanesi, Padua (IT)
Assignee Infineon Technologies AG, Neubiberg (DE)

Claim of US Patent No. 10,560,990

1. A circuit configured to monitor current through two or more strings of light emitting diodes, the circuit comprising:a power converter;
a first current sensing resistor, wherein the first current sensing resistor is positioned between a first node and a second node of the circuit;
a second current sensing resistor connected in series with the first current sensing resistor, wherein the second current sensing resistor is positioned between the second node and a third node of the circuit; and
a first electrical contact element at the first node and a second electrical contact element at the third node, wherein the first electrical contact element and the second electrical contact element are coupled to the power converter,
wherein current from the power converter flows through a first LED string and a second LED string in a complimentary fashion such that when current flows through the first LED string approximately zero current flows through the second LED string, and when current flows through the second LED string approximately zero current flows through the first LED string,
wherein a voltage drop between the first electrical contact element and the second electrical contact element is defined by the first current sensing resistor when current flows through the first LED string, and
wherein the voltage drop between the first electrical contact element and the second electrical contact element is defined by the first current sensing resistor and the second current sensing resistor when current flows through the second LED string.