US 12,224,718 B2
Transimpedance amplifiers
Matthew George Hagman, Gatineau (CA); and Behzad Farzaneh, London (GB)
Assigned to Semtech Corporation, Camarillo, CA (US)
Filed by Semtech Corporation, Camarillo, CA (US)
Filed on Feb. 2, 2022, as Appl. No. 17/591,208.
Prior Publication US 2023/0246603 A1, Aug. 3, 2023
Int. Cl. H03F 3/08 (2006.01); H03G 3/30 (2006.01)
CPC H03F 3/087 (2013.01) [H03G 3/3084 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A transimpedance amplifier circuit comprising:
a transimpedance amplifier configured to generate a first voltage based on a current at an input node for an input signal;
a controlled voltage source for generating a second voltage based on a first control current; and
a controller for collectively controlling the first control current and a second control current based on an indication of an input signal magnitude, wherein the second control current is subtracted from the current at the input node, wherein the controller is configured such that:
for a first range of the input signal magnitude, a first magnitude of the first control current depends on the input signal magnitude and increases with increasing the input signal magnitude whilst a second magnitude of the second control current is substantially constant; and
for a second, higher, range of the input signal magnitude, both the first magnitude of the first control current and the second magnitude of the second control current depend on the input signal magnitude and the second magnitude of the second control current increases with increasing the input signal magnitude while the first magnitude of the first control current reduces.