US 12,413,045 B2
Laser driver incorporating clamping circuit with freewheeling diode
Marco Zamprogno, Cesano Maderno (IT); and Alireza Tajfar, Milan (IT)
Assigned to STMicroelectronics S.r.l., Agrate Brianza (IT); and POLITECNICO DI MILANO, Milan (IT)
Filed by STMicroelectronics S.r.l., Agrate Brianza (IT); and POLITECNICO DI MILANO, Milan (IT)
Filed on Jun. 28, 2022, as Appl. No. 17/852,100.
Application 17/852,100 is a continuation of application No. 17/026,495, filed on Sep. 21, 2020, granted, now 11,418,007.
Application 17/026,495 is a continuation of application No. 16/454,717, filed on Jun. 27, 2019, granted, now 10,826,268, issued on Nov. 3, 2020.
Prior Publication US 2022/0329042 A1, Oct. 13, 2022
Int. Cl. H01S 3/00 (2006.01); H01S 5/042 (2006.01); H01S 5/062 (2006.01); H01S 5/068 (2006.01)
CPC H01S 5/0428 (2013.01) [H01S 5/042 (2013.01); H01S 5/0427 (2013.01); H01S 5/06216 (2013.01); H01S 5/06825 (2013.01); H01S 5/06226 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A circuit, comprising:
an input node configured to be coupled to a cathode of a laser diode having its anode coupled to a high voltage supply node;
a cascoded current mirror having an input branch and an output branch, wherein the input branch is coupled between the high voltage supply node and a sense resistor coupled to the input node, and wherein the output branch is coupled between the high voltage supply node and an output node;
a sense circuit coupled between the output node and ground, wherein the sense circuit comprises a diode coupled transistor coupled to the output node and a resistor coupled between the diode coupled transistor and a ground node;
wherein the input branch is configured to generate a current proportional to a voltage drop across the laser diode;
wherein the output branch is configured to generate a mirrored current proportional to the current proportional to the voltage drop across the laser diode;
wherein a voltage proportional to the voltage drop across the laser diode is generated as a result of the mirrored current flowing through the sense resistor; and
a comparison circuit configured to compare the voltage proportional to the voltage drop across the laser diode to a threshold voltage.