Current driver for diode laser system
View Patent ↗An architecture for current driver circuitry for diode laser systems is contemplated whereby the circuitry is both modular and minimally complex with respect to the number of components and connections.
1. A current driver for a diode system, comprising
a current regulator that is configured to receive from a power supply a bias voltage, wherein the bias voltage shifts a compliance voltage range of the current regulator to include a knee voltage of a diode load, and wherein the bias voltage has a value that corresponds to a lower bound of the shifted compliance voltage range; and
a switch element that is coupled to the current regulator and to the diode load, the switch element configured to detect a voltage level that is output by the current regulator to supply drive current to the diode load, wherein the switch element has (a) a high impedance when the voltage level that is output by the current regulator to supply drive current to the diode load is less than the value of the bias voltage and (b) a low impedance when the voltage level that is output by the current regulator to supply drive current to the diode load is greater than a sum of a threshold voltage value and the value of the bias voltage.
2. The current driver of claim 1 , wherein the compliance voltage range is 60V or less in magnitude.
3. The current driver of claim 1 , wherein the switch element is a PMOS transistor, and a source node of the PMOS transistor is coupled to the current regulator, a gate node of the PMOS transistor is biased by the bias voltage, and a drain node of the PMOS transistor provides for drive current a path to the diode load.
4. The current driver of claim 1 , wherein the switch element is an NMOS transistor, and a source node of the NMOS transistor is coupled to the current regulator, a gate node of the NMOS transistor is biased by the bias voltage, and a drain node of the NMOS transistor provides for drive current a path to the diode load.
5. The current driver of claim 1 , wherein the current regulator is powered by a difference between a supply voltage that is twice the bias voltage in magnitude and the bias voltage.
6. The current driver of claim 1 , wherein the current regulator is powered by a difference between a supply voltage that is less than twice the bias voltage in magnitude and the bias voltage.
7. The current driver of claim 1 , further comprising a damping resistor that is coupled in series with a capacitor that is coupled to an output node of the current regulator, wherein the damping resistor has an electrical resistance selected from between 15 milliohms to 1000 milliohms inclusive.
8. The current driver of claim 1 , wherein the current regulator is a synchronous buck converter.
9. The current driver of claim 1 , wherein a modulation frequency of the current regulator is about 100 kHz or less.
10. A diode system, comprising:
a diode load;
a power supply that is configured to output a bias voltage;
a current regulator that is coupled to the power supply and that is configured to receive from the power supply the bias voltage, wherein the bias voltage shifts a compliance voltage range of the current regulator to include a knee voltage of the diode load, and wherein the bias voltage has a value that corresponds to a lower bound of the shifted compliance voltage range; and
a switch element that is coupled to the current regulator and to the diode load, the switch element configured to detect a voltage level that is output by the current regulator to supply drive current to the diode load, wherein the switch element has (a) a high impedance when the voltage level that is output by the current regulator to supply drive current to the diode load is less than the value of the bias voltage and (b) a low impedance when the voltage level that is output by the current regulator to supply drive current to the diode load is greater than a sum of a threshold voltage value and the value of the bias voltage.
11. The diode system of claim 10 , wherein the compliance voltage range is 60V or less in magnitude.
12. The diode system of claim 10 , wherein the switch element is a PMOS transistor, and a source node of the PMOS transistor is coupled to the current regulator, a gate node of the PMOS transistor is biased by the bias voltage, and a drain node of the PMOS transistor provides for drive current a path to the diode load.
13. The diode system of claim 10 , wherein the switch element is an NMOS transistor, and a source node of the NMOS transistor is coupled to the current regulator, a gate node of the NMOS transistor is biased by the bias voltage, and a drain node of the NMOS transistor provides for drive current a path to the diode load.
14. The diode system of claim 10 , wherein the current regulator is powered by a difference between a supply voltage that is less than or equal to twice the bias voltage in magnitude and the bias voltage.
15. The diode system of claim 10 , wherein the diode load includes a plurality of series-connected diodes.
16. The diode system of claim 10 , further comprising a damping resistor that is coupled in series with a capacitor that is coupled to an output node of the current regulator, wherein the damping resistor has an electrical resistance selected from between 15 milliohms to 1000 milliohms inclusive.
17. The diode system of claim 10 , wherein the current regulator is a synchronous buck converter.
18. The diode system of claim 10 , wherein a modulation frequency of the current regulator is about 100 kHz or less.
19. The diode system of claim 10 , wherein the power supply includes a pair of series-connected voltage sources, and wherein a first voltage source of the pair is configured to output the bias voltage and a second voltage source of the pair is configured to output a supply voltage that has a magnitude equal to or different than a magnitude of the bias voltage.
20. A current driver for a diode laser system, comprising
a current regulator that is configured to receive from a power supply a bias voltage, wherein the bias voltage shifts a compliance voltage range of the current regulator to include a knee voltage of a laser diode load, and wherein the bias voltage has a value that corresponds to a lower bound of the shifted compliance voltage range; and
a transistor that is coupled to the current regulator and that is configured to detect a voltage level that is output by the current regulator to supply drive current to the laser diode load, wherein the transistor has (a) a high impedance when the voltage level that is output by the current regulator to supply drive current to the laser diode load is less than the value of the bias voltage and (b) a low impedance when the voltage level that is output by the current regulator to supply drive current to the laser diode load is greater than a sum of a threshold voltage value and the value of the bias voltage;
wherein a source node of the transistor is coupled to the current regulator, a gate node of the transistor is biased by the bias voltage, and a drain node of the transistor provides for drive current a path to the laser diode load.