FAULT PROTECTOR FOR OPTO-ELECTRONIC DEVICES AND ASSOCIATED METHODS

• US 20110110005A1
• Filed: 07/09/2009
• Published: 05/12/2011
• Est. Priority Date: 07/11/2008
• Status: Active Grant

• Current Assignee: William R. Benner Jr
• Original Assignee: William R. Benner Jr
• Inventors: Benner, William R. Jr.
• Granted Patent: US 8,902,557 B2
• Time in Patent Office: Days
• US Class Current: 361/56
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01S 5/06825 Protecting the laser, e.g. during switch-on/off, detection of malfunctioning or degradation
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A fault protector for an opto-electronic device includes a MOSFET having an integral body-diode. A capacitor is connected between a drain and a gate of the MOSFET, and a resistor is connected between the gate and a source of the MOSFET. The drain of the MOSFET is connectable to a first terminal of an opto-electronic device, and the source of the MOSFET is connectable to a second terminal of the opto-electronic device. The device overcomes problems of previously known techniques by preventing a reverse-bias voltage from exceeding an absolute maximum specified by a manufacturer, and also prevents ESD or other power-related faults from exceeding the maximum forward-bias voltage of the laser diode, while not adding significant resistance or capacitance to the laser diode, thereby not complicating the task of driving the laser diode.

Claims

1. An electronic circuit comprising:

an enhancement-mode MOSFET having a gate controlling current between a source and a drain, the MOSFET including a body-diode operable therewith;

capacitor means connected between the drain and the gate of the MOSFET;

resistor means connected between the source and the gate of the MOSFET,

wherein the drain is connectable to a first terminal of an opto-electronic device and the source is connectable to a second terminal of the opto-electronic device, the second terminal distinct from the first terminal.

2. The circuit according to claim 1, further comprising an opto-electronic device, the opto-electronic device at least one of a laser diode and a light emitting diode.

3. The circuit according to claim 1, wherein the circuit forms a fault protector implemented as one of discrete components and as an integral part of the opto-electronic device.

4. The circuit according to claim 1, wherein the MOSFET is one of an N-channel MOSFET and a P-channel MOSFET.

5. The circuit according to claim 1, wherein the body-diode is a fast recovery body diode.

6. The circuit according to claim 1, wherein a gate to source threshold voltage applied to the MOSFET is below 0.5 volts.

7. The circuit according to claim 1, wherein the resistor means comprises first resistor means, and wherein the circuit further comprises second resistor means connected between the drain and the gate, the first and second resistor means each providing a partial biasing for maintaining the gate at a desired voltage.

8. The circuit according to claim 7, wherein the second resistor means forms a parallel connection with the capacitive means.

9. The circuit according to claim 1, wherein the body-diode is integrally formed within a body of the MOSFET.

10. An electronic circuit useful as a fault protector for opto-electronic devices, the circuit comprising:

an enhancement-mode MOSFET having a gate controlling current between a source and a drain, the MOSFET including a body-diode;

capacitor means connected between the drain and the gate of the MOSFET;

resistor means having a first terminal connected to the gate of the MOSFET and a second terminal for connecting to an external terminal,

wherein the drain of the MOSFET is connectable to a first terminal of an opto-electronic device and the source of the MOSFET is connectable to a second terminal of the opto-electronic device, the second terminal distinct from the first terminal.

11. The circuit according to claim 10, further comprising second resistor means connected between the drain and the gate of the MOSFET.

12. The circuit according to claim 10, further comprising an opto-electronic device, the opto-electronic device at least one of a laser diode and a light emitting diode.

13. The circuit according to claim 10, wherein the circuit forms a fault protector implemented as one of discrete components and as an integral part of the opto-electronic device.

14. The circuit according to claim 10, wherein the MOSFET is one of an N-channel MOSFET and a P-channel MOSFET.

15. The circuit according to claim 10, wherein the body-diode is a fast recovery body-diode.

16. The circuit according to claim 10, wherein a gate to source threshold voltage applied to the MOSFET is below 0.5 volts.

17. The circuit according to claim 10, further comprising a power fault detector, the power fault detector having the external terminal for connection to the resistor means.