Methods and systems of driving arrays of diodes

1 . A diode driver for driving an array of laser diodes, comprising:

a power supply terminal;

a ground terminal;

a first and second inductor terminals;

a plurality of driver terminals;

a substrate of semiconductor material;

a plurality of row switches defined on the substrate, the plurality of row switches defining a respective plurality of control inputs, each of the plurality of row switches coupled to the second inductor terminal, and the plurality of row switches coupled one each to the plurality of driver terminals;

a high-side switch defined on the substrate, the high-side switch defines a first lead coupled to the power supply terminal, a second lead coupled to the first inductor terminal, and a control input;

a low-side switch defined on the substrate, the low-side switch defines a first lead coupled to the first inductor terminal, a second lead coupled to the ground terminal, and a control input;

a shorting switch defined on the substrate, the shorting switch defines a first lead coupled to the second inductor terminal, a second lead coupled to the ground terminal, and a control input;

a controller defined on the substrate and coupled to the plurality of control inputs, and coupled to the control inputs of the high-side switch, low-side switch, and the shorting switch, the controller configured to:

close the high-side switch, close the shorting switch, and open the low-side switch to increase an inductor current through an inductor coupled across the first and second inductor terminals, close a first row switch of the plurality of row switches,

open the high-side switch, close the low-side switch, and open the shorting switch to drive the inductor current to a first driver terminal of the plurality of driver terminals, and then

close the shorting switch to recirculate the inductor current; and

a pulse request terminal,

wherein when the controller increases the inductor current, the controller is further configured to increase the inductor current responsive to assertion of the pulse request terminal.

2 . The diode driver of claim 1 , wherein the controller is further configured to close the first row switch before or after closing the shorting switch.

3 . The diode driver of claim 1 , wherein the controller is further configured to, after recirculation of the inductor current:

open the low-side switch, close the high-side switch, and close the shorting switch to increase the inductor current through the inductor,

open the high-side switch, close the low-side switch, open the shorting switch, and close a second row switch of the plurality of row switches to drive the inductor current to a second driver terminal of the plurality of driver terminals, and then

close the shorting switch to recirculate the inductor current.

4 . The diode driver of claim 1 , further comprising a pulse-end terminal, wherein the controller is further configured to assert the pulse-end terminal simultaneously with the recirculation of the inductor current.

5 . A LIDAR system, comprising:

an array of laser diodes defining a plurality of rows, the laser diodes of each row configured to be driven simultaneously;

a power supply terminal;

a ground terminal;

an inductor defining a first lead and a second lead;

a plurality of driver terminals;

a substrate of semiconductor material;

a plurality of row switches defined on the substrate, the plurality of row switches defining a respective plurality of control inputs, each of the plurality of row switches coupled to the second lead of the inductor, and the plurality of row switches coupled one each to the plurality of rows of the array of laser diodes;

a high-side switch defined on the substrate, the high-side switch defining a first lead coupled to a power supply, a second lead coupled to the first lead of the inductor, and a control input;

a low-side switch defined on the substrate, the low-side switch defining a first lead coupled to the first lead of the inductor, a second lead coupled to a ground, and a control input;

a shorting switch defined on the substrate, the shorting switch defining a first lead coupled to the second lead of the inductor, a second lead coupled to the ground, and a control input;

a controller defined on the substrate and coupled to the plurality of control inputs, and coupled to the control inputs of the high-side switch, low-side switch, and the shorting switch, the controller configured to:

increase an inductor current through the inductor by commanding to close the high-side switch, close the shorting switch, and open the low-side switch,

couple a first row of the plurality of rows to the second lead of the inductor by commanding to close a first row switch of the plurality of row switches,

drive the inductor current to the first row by command to open the high-side switch, close the low-side switch, and open the shorting switch, and then

recirculate the inductor current by command to close the shorting switch; and

a pulse request terminal,

wherein when the controller increases the inductor current, the controller is configured to increase the inductor current responsive to assertion of the pulse request terminal.

6 . The LIDAR system of claim 5 , wherein the controller is further configured command the first row switch to close before or after commanding the shorting switch to close.

7 . The LIDAR system of claim 5 , further comprising a pulse-end terminal, wherein the controller is further configured to assert the pulse-end terminal simultaneously with the recirculation of the inductor current.

8 . The LIDAR system of claim 5 , wherein the controller is further configured to, after recirculation of the inductor current:

increase the inductor current through the inductor by commanding to close the high-side switch, close the shorting switch, and open the low-side switch,

drive the inductor current to a second row of the plurality of rows of the array of laser diodes by commend to open the high-side switch, close the low-side switch, open the shorting switch, and close a second row switch of the plurality of row switches, and then

recirculate the inductor current by commanding to close the shorting switch.