Power MOSFETs with improved efficiency for multi-channel class D audio amplifiers and packaging therefor
View Patent ↗A stereo class-D audio system includes a first die including four monolithically integrated NMOS high-side devices and a second a second die including four monolithically integrated PMOS low-side devices. The audio system also includes a set of electrical contacts for connecting the high and low-side devices to components within the a stereo class-D audio system, the set of electrical contacts including at least one supply contact for connecting the drains of the high-side devices to a supply voltage (Vcc) and at least one ground contact for connecting the drains of the low-side devices to ground, the electrical contacts also including respective contacts for each source of the high and low-side devices allowing the source of each high-side device to be connected to the source of a respective low-side device to form two H-bridge circuits.
1. A stereo class-D audio system comprising:
four NMOS high-side devices;
four NMOS low-side devices; a source of each high-side device being connected to a drain of a respective low-side device to form four half-bridge circuits with the four half-bridge circuits grouped as two half-bridge pairs, each half-bridge circuit haying an output node at the sourced of its high-side device and the drain of its low-side device;
a package containing the two half-bridge pairs; and
a set of electrical contacts for connecting the class-D audio system to an external circuit, the set of electrical contacts including at least one supply contact and at least one ground contact for each of the two half-bridge pairs, the supply contact of each half-bridge pair connected to the drains of the NMOS high-side devices within that half-bridge pair and the ground contact of each half-bridge pair connected to the sources of the NMOS low-side devices within that half-bridge pair, the electrical contacts also including at least one output contact for each output node of each half-bridge circuit.
2. The stereo Class D audio system of claim 1 further comprising four break-before-make buffers connected to the four half-bridge circuits, respectively.
3. The stereo Class D audio system of claim 2 wherein each of the four break-before-make buffers is connected to a gate of an NMOS high-side device and a gate of an NMOS low-side device within one of the four half-bridge circuits.
4. The stereo Class D audio system of claim 2 further comprising a stereo Class D audio system connected to each of the four break-before-make buffers.
5. The stereo Class D audio system of claim 1 wherein each of the four NMOS high-side devices and each of the four NMOS low-side devices is a vertical DMOS device.
6. The stereo Class D audio system of claim 5 wherein each of the NMOS low-side devices is a discrete device.
7. The stereo Class D audio system of claim 6 wherein all of the NMOS high-side devices share a single silicon chip.
8. The stereo Class D audio system of claim 6 wherein two of the NMOS high-side devices in a first half-bridge pair share a first silicon chip and two of the NMOS high-side devices in a second half-bridge pair share a second silicon chip.
9. The stereo Class D audio system of claim 5 wherein the drains of the four NMOS high-side devices are mounted to a single die pad.
10. The stereo Class D audio system of claim 9 wherein the drains of the four NMOS low-side devices are mounted to four separate die pads, respectively.
11. The stereo Class D audio system of claim 10 wherein the source of each of the four NMOS high-side devices is electrically connected by a bonding wire to one of the output contacts.
12. The stereo Class D audio system of claim 11 wherein each of the four separate die pads is electrically connected to one of the output contacts.
13. The stereo Class D audio system of claim 12 wherein the single die pad is electrically connected to the at least one supply contact.
14. The stereo Class D audio system of claim 13 wherein the source of each of the four NMOS low-side devices is electrically connected by a bonding wire to the at least one ground contact.
15. The stereo Class D audio system of claim 10 wherein the four separate die pads are mounted in a single row in the package.
16. The stereo Class D audio system of claim 10 wherein two of the separate die pads are mounted in the package on an opposite side of the single die pad from a remaining two of the separate die pads.
17. The stereo Class D audio system of claim 16 wherein the single die pad is H-shaped.
18. The stereo Class D audio system of claim 17 wherein the source of each of the four NMOS high-side devices is electrically connected by a bonding wire to one of the four separate die pads.
19. The stereo Class D audio system of claim 18 wherein each of the four separate die pads comprises one of the output contacts.
20. The stereo Class D audio system of claim 19 wherein the single die pad is electrically connected to the at least one supply contact.
21. The stereo Class D audio system of claim 20 wherein the source of each of the four NMOS low-side devices is electrically connected by a bonding wire to the at least one ground contact.