Passive peaking circuit comprising a step-down impedance transformer
View Patent ↗A passive peaking circuit is formed in part from a passive step-down impedance transformer that interconnects the light source driver to the light source. The step-down impedance transformer has impedance that decreases in a continuous or discrete manner in the direction from the light source driver circuit to the light source. The passive peaking circuit peaks the electrical drive signal being delivered from the light source driver circuit to the light source, thereby widening the eye opening.
1. A passive peaking circuit comprising:
a light source circuit comprising at least a first light source disposed on one of a printed circuit board or a flex circuit;
a light source driver circuit comprising at least a first light source driver that produces a first electrical drive signal for driving the first light source disposed on a remaining one of the printed circuit board or the flex circuit; and
a step-down impedance transformer having a first portion and a second portion and electrically interconnecting the light source driver circuit and the light source circuit, the first portion disposed with the light source driver circuit on the remaining one of the printed circuit board or the flex circuit, the step-down impedance transformer passively peaking the first electrical drive signal.
2. The passive peaking circuit of claim 1 , wherein the step-down impedance transformer comprises at least a first electrically-conductive trace having a first end electrically connected to the light source driver circuit and a second end electrically connected to the light source circuit, wherein at least a first portion of the first trace that includes the second end of the first trace has a width that increases in a direction from the first end of the trace to the second end of the trace, and wherein the increase in width results in a decrease in impedance along said first portion of the first trace in the direction from the light source driver circuit to the light source circuit.
3. The passive peaking circuit of claim 2 , wherein the first electrically-conductive trace comprises N electrically-conductive trace segments, where N is an integer having a value that is equal to or greater than two, wherein the trace segments are connected end to end to form the first electrically-conductive trace, and wherein the trace segments comprising said first portion of the first trace increase in width in the direction from the light source driver circuit to the light source circuit.
4. The passive peaking circuit of claim 3 , wherein each trace segment has a constant width, and wherein the widths of the trace segments comprising said first portion of the first trace increase in a discrete manner in the direction from the light source driver circuit to the light source circuit such that the width of said first portion of the first trace increases in discrete steps in the direction from the light source driver circuit to the light source circuit.
5. The passive peaking circuit of claim 4 , wherein the increases in width are equal.
6. The passive peaking circuit of claim 4 , wherein at least some of the increases in width are unequal.
7. The passive peaking circuit of claim 3 , wherein each trace segment of said portion of the first trace has a variable width.
8. The passive peaking circuit of claim 7 , wherein the width of each trace segment of said first portion of the first trace increases in a linear manner such that the width of said first portion of the first trace increases in a nonlinear manner in the direction from the light source driver circuit to the light source circuit.
9. The passive peaking circuit of claim 8 , wherein the width of each trace segment of said first portion of the first trace increases in a nonlinear manner such that the width of said first portion of the first trace increases in a nonlinear manner in the direction from the light source driver circuit to the light source circuit.
10. The passive peaking circuit of claim 2 , wherein said first portion of the first trace is disposed on the printed circuit board.
11. The passive peaking circuit of claim 2 , wherein said first portion of the first trace is disposed on the flex circuit.
12. The passive peaking circuit of claim 11 , wherein the second portion of the first trace is disposed on the printed circuit board.
13. The passive peaking circuit of claim 12 , wherein the light source driver circuit is disposed on the printed circuit board and the light source circuit is disposed on the flex circuit, and wherein said second portion of the first trace is electrically connected to the light source driver circuit.
14. The passive peaking circuit of claim 1 , wherein the step-down impedance transformer passively peaks the first electrical drive signal by increasing a maximum magnitude of the electrical drive signal along a rising edge of the electrical drive signal.
15. The passive peaking circuit of claim 14 , wherein the step-down impedance transformer passively peaks the first electrical drive signal by decreasing a minimum magnitude of the electrical drive signal along a falling edge of the electrical drive signal.
16. A passive peaking circuit comprising:
a laser diode circuit comprising at least a first laser diode on one of a printed circuit board or a flex circuit;
a laser diode driver circuit comprising at least a first laser diode driver that produces a first electrical drive signal for driving the first laser diode on a remaining one of the printed circuit board or the flex circuit; and
a step-down impedance transformer having a first portion and a second portion and directly electrically interconnecting the laser diode driver circuit and the laser diode circuit, the first portion proximal to the laser diode driver circuit on the remaining one of the printed circuit board or the flex circuit, the second portion adjacent to the laser diode circuit, the step-down impedance transformer passively peaking the first electrical drive signal, wherein the step-down impedance transformer comprises at least a first electrically-conductive trace having a first end electrically connected to the laser diode driver circuit and a second end electrically connected to the laser diode circuit, wherein at least the first portion of the first trace that includes the second end of the first trace has a width that increases in a direction from the first end of the trace to the second end of the trace, and wherein the increase in width results in a decrease in impedance along said first portion of the first trace in the direction from the laser diode driver circuit to the laser diode circuit.
17. The passive peaking circuit of claim 16 , wherein the first electrically-conductive trace comprises N electrically-conductive trace segments, where N is an integer having a value that is equal to or greater than two, wherein the trace segments are connected end to end to form the first electrically-conductive trace, and wherein the trace segments comprising said first portion of the first trace increase in width in the direction from the laser diode driver circuit to the laser diode circuit.
18. The passive peaking circuit of claim 17 , wherein each trace segment has a constant width, and wherein the widths of the trace segments comprising said first portion of the first trace increase in a discrete manner in the direction from the laser diode driver circuit to the laser diode circuit such that the width of said first portion of the first trace increases in discrete steps in the direction from the laser diode driver circuit to the laser diode circuit.
19. The passive peaking circuit of claim 17 , wherein each trace segment of said portion of the first trace has a variable width, wherein the width of each trace segment of said first portion of the first trace increases in a linear manner such that the width of said first portion of the first trace increases in a nonlinear manner in the direction from the laser diode driver circuit to the laser diode circuit.
20. The passive peaking circuit of claim 17 , wherein each trace segment of said portion of the first trace has a variable width, wherein the width of each trace segment of said first portion of the first trace increases in a nonlinear manner such that the width of said first portion of the first trace increases in a nonlinear manner in the direction from the laser diode driver circuit to the laser diode circuit.
21. A passive peaking circuit comprising:
a light-emitting diode circuit on one of a printed circuit board or a flex circuit;
a driver circuit on a remaining one of the printed circuit board or the flex circuit that produces a first electrical drive signal for driving the light-emitting diode circuit; and
a step-down impedance transformer having a first portion and a second portion and directly electrically interconnecting the driver circuit and the light-emitting diode circuit, the first portion proximal to the driver circuit on the remaining one of the printed circuit board or the flex circuit, the step-down impedance transformer passively peaking the first electrical drive signal, wherein the step-down impedance transformer comprises at least a first electrically-conductive trace having a first end electrically connected to the driver circuit and a second end electrically connected to the light-emitting diode circuit, wherein at least a first portion of the first trace that includes the second end of the first trace has a width that increases in a direction from the first end of the trace to the second end of the trace, and wherein the increase in width results in a decrease in impedance along said first portion of the first trace in the direction from the driver circuit to the light-emitting diode circuit.
22. The passive peaking circuit of claim 21 , wherein the first electrically-conductive trace comprises N electrically-conductive trace segments, where N is an integer having a value that is equal to or greater than two, wherein the trace segments are connected end to end to form the first electrically-conductive trace, and wherein the trace segments comprising said first portion of the first trace increase in width in the direction from the driver circuit to the light-emitting diode circuit.
23. The passive peaking circuit of claim 22 , wherein each trace segment has a constant width, and wherein the widths of the trace segments comprising said first portion of the first trace increase in a discrete manner in the direction from the driver circuit to the light-emitting diode circuit such that the width of said first portion of the first trace increases in discrete steps in the direction from the driver circuit to the light-emitting diode circuit.
24. The passive peaking circuit of claim 22 , wherein each trace segment of said portion of the first trace has a variable width, wherein the width of each trace segment of said first portion of the first trace increases in a linear manner such that the width of said first portion of the first trace increases in a nonlinear manner in the direction from the driver circuit to the light-emitting diode circuit.
25. The passive peaking circuit of claim 22 , wherein each trace segment of said portion of the first trace has a variable width, wherein the width of each trace segment of said first portion of the first trace increases in a nonlinear manner such that the width of said first portion of the first trace increases in a nonlinear manner in the direction from the driver circuit to the light-emitting diode circuit.