1. A light source comprising:
at least one light emitting diode (LED); and
at least one thermally conductive translucent element positioned in thermal contact with said at least one LED, to perform its principal function of thermal spreading the heat generated by said at least one LED;
wherein more than half of the heat generated within the light source is dissipated by said at least one thermally conductive translucent element and wherein the light generated within the light source also is emitted through said at least one thermally conductive translucent element.
2. The light source of claim 1 further comprising
at least one reflector positioned to redirect light emitted by said at least one LED back through said at least one thermally conductive translucent element.
3. The light source of claim 2 further comprising
a wavelength conversion layer between said at least one LED and said at least one reflector.
4. The light source of claim 3 further comprising
a flex connector.
5. The light source of claim 4 further comprising
said at least one thermally conductive translucent element formed from at least one of the following materials, Al2O3, AlON, YAG, SiC, spinel, and MgO.
6. A light source comprising
at least one LED and
at least one thermally conductive translucent element
and a luminescent material bonded to said at least one thermally conductive translucent element
wherein the light emitted by said at least one LED is waveguided through said at least one thermally conductive translucent element before impinging on said luminescent material and wherein the heat generated by said at least one LED is spread out through said at least one thermally conductive translucent element.
7. The light source of claim 6 wherein said luminescent material is on the light emission face of said at least one translucent thermally conductive element.
8. The light source of claim 6 wherein said luminescent material is on the inside face of said at least one translucent thermally conductive element such the light emitted from said at least one LED is spread out via said at least one translucent thermally conductive element and is reflected back from said luminescent material and then passes back through said at least one translucent thermally conductive element before being emitted.
9. The light source of claim 6 wherein the light output face of said at least one translucent thermally conductive element dissipates over 50% of the heat generated by said at least one LED in the light source.
10. A light source comprising
at least one LED and
at least one thermally conductive translucent element
wherein said at least one LED is bonded to a electrical interconnect on said at least one thermally conductive translucent element and the heat generated by said at least one LED is spread out and dissipated through said at least one thermally conductive translucent element.
11. The light source of claim 10 wherein said at least one thermally conductive translucent face opposite of said at least one LED is exposed to ambient air and dissipates more than 50% of the heat generated by said at least one LED.
12. The light source of claim 11 further comprising
a translucent luminescent matrix coated over said at least one LED and
a reflector positioned so as to reflect light converted by said luminescent element back through said luminescent element and through said at least one thermally conductive translucent element.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method, comprising:
switching on an MOS transistor by precharging an input capacitance of the MOS transistor with a substantially constant amount of charge in a precharging phase, and charging the input capacitance with a controlled charging current after the precharging phase.
2. The method of claim 1, wherein the controlled charging current is substantially constant.
3. The method of claim 1, wherein the precharging phase has a substantially fixed duration.
4. The method of claim 3, wherein precharging the input capacitance in the precharging phase comprises:
controlling a precharging current to have a predefined current profile.
5. The method of claim 4, wherein the predefined current profile is selected from one of:
a rectangular current profile;
a trapezoidal current profile;
a current profile corresponding to a half wave of a sine signal; and
a current profile corresponding to a half wave of a sine-square signal.
6. The method of claim 1, wherein a maximum current level of the charging current is lower than a mean current level of a precharging current in the precharging phase.
7. The method of claim 6, wherein a maximum current level of the charging current is at most 60% of a mean level of a precharging current in the precharging phase.
8. The method of claim 1, wherein the MOS transistor is one of a MOSFET, and an IGBT.
9. A drive circuit configured to switch on an MOS transistor by precharging an input capacitance of the MOS transistor with a substantially constant amount of charge in a precharging phase, and charging the input capacitance with a controlled charging current after the precharging phase.
10. The drive circuit of claim 9, comprising:
a controlled current source configured to provide a current in accordance with a current source control signal; and
a current source controller configured to generate the current source control signal such that the controlled current source, in the precharging phase, provides the substantially constant amount of charge, and, after the precharging phase, provides the controlled charging current.
11. The drive circuit of claim 10, wherein the current source controller is configured to generate the current source control signal with a first signal level for a predefined time period, and to generate the current source control signal with a second signal level different from the first signal level after the predefined time period.
12. The drive circuit of claim 11, wherein the current source controller comprises a voltage divider, and wherein the first signal level is dependent on an output signal of the voltage divider.
13. The drive circuit of claim 12, wherein the drive circuit comprises an integrated circuit package, and wherein the voltage divider is located outside the integrated circuit package.
14. An electronic circuit comprising:
an MOS transistor; and
a drive circuit configured to switch on an MOS transistor by precharging an input capacitance of the MOS transistor with a substantially constant amount of charge in a precharging phase, and charging the input capacitance with a controlled charging current after the precharging phase.
15. The electronic circuit of claim 14, wherein the MOS transistor is one of an IGBT and a MOSFET.