US 12,439,491 B2
Method and apparatus for noise rejection in drivers for diodes
Junjie Lu, Irvine, CA (US); Jing Guo, Irvine, CA (US); Naga Radha Krishna Damaraju, Irvine, CA (US); and Xicheng Jiang, Irvine, CA (US)
Assigned to Avago Technologies International Sales Pte. Limited, Singapore (SG)
Filed by Avago Technologies International Sales Pte. Limited, Singapore (SG)
Filed on Mar. 27, 2023, as Appl. No. 18/126,927.
Prior Publication US 2024/0334567 A1, Oct. 3, 2024
Int. Cl. H05B 45/30 (2020.01); H05B 45/345 (2020.01); H05B 45/36 (2020.01)
CPC H05B 45/36 (2020.01) [H05B 45/345 (2020.01)] 20 Claims
OG exemplary drawing
 
1. A device, comprising:
a first circuit;
a ground node;
a reference voltage source configured to provide a reference voltage;
a first transistor that comprises a first drain node, a first source node, and a first gate node, wherein the first circuit is coupled between the first source node and the ground node;
a second transistor that comprises a second source node and a second gate node, wherein the second transistor is configured to be biased as a source follower with the second source node being set at the reference voltage, wherein:
the first gate node is coupled to the second gate node,
the first source node has equal voltage as the second source node,
the first circuit is configured to drive a constant current from the first source node,
a voltage of the first source node is independent of a voltage of the first drain node of first transistor, and
the first transistor is biased in a saturation region to reduce a parasitic capacitance;
a group of one or more switches to: (i) connect the first gate node of the first transistor to the ground node or the second gate node and (ii) the second gate node to the ground node or a third gate node; and
a controller configured to determine an amount of current and based at least on the amount of current turns on or off each of the one or more switches of the group.