Structure and method for a switched circuit device

1. A semiconductor circuit for receiving a source voltage and producing an output voltage, the circuit comprising:

a switch controller;

a switched device communicatively coupled to the switch controller and having a source and drain, the switch controller controlling a duty cycle of the switched device;

a diode coupled between the source and the drain of the switched device; and

an inductor coupled to at least one of the source of the switched device or the drain of the switched device;

wherein the inductor is directly electrically coupled to a body of the switched device;

wherein the switched device is characterized by a drain-to-source breakdown voltage greater than or substantially equal to a greater of the source voltage and the output voltage; and

wherein the switched device is further characterized by a hot-carrier injection rating less than a greater of the source voltage and the output voltage.

2. The semiconductor circuit of claim 1 , wherein the hot-carrier injection rating is a nominal operating area rating.

3. The semiconductor circuit of claim 1 , wherein the hot-carrier injection rating is a DC 0.2-year safe operating area rating.

4. The semiconductor circuit of claim 1 ,

wherein the switched device is a first switched device;

wherein the semiconductor circuit further comprises a second switched device communicatively coupled to the switch controller, the switch controller further controlling a duty cycle of the second switched device;

wherein the first and second switched devices are part of a complementary pair;

wherein the second switched device is characterized by a drain-to-source breakdown voltage greater than or substantially equal to a greater of the source voltage and the output voltage; and

wherein the second switched device is further characterized by a hot-carrier injection rating less than a greater of the source voltage and the output voltage.

5. The semiconductor circuit of claim 1 configured as a buck converter, wherein the output voltage is less than the source voltage, and wherein the inductor is arranged to provide the output voltage.

6. The semiconductor circuit of claim 1 configured as a boost converter, wherein the output voltage is greater than the source voltage, and wherein the inductor is arranged to receive the source voltage.

7. The semiconductor circuit of claim 1 ,

wherein the switched device is a laterally diffused metal-oxide-semiconductor (LDMOS) device; and

wherein a drift region length of the switched device determines the breakdown voltage and the hot-carrier injection rating.

8. The semiconductor circuit of claim 1 ,

wherein the switched device is a field-effect transistor (FET) device; and

wherein a channel region length of the switched device determines the breakdown voltage and the hot-carrier injection rating.

9. A circuit device receiving an input voltage and producing an output voltage, the circuit device comprising:

a switch controller;

a switched device communicatively coupled to the switch controller and having a drain and a source, the switch controller controlling a duty cycle of the switched device to produce the output voltage;

a diode coupled to the source and the drain of the switched device;

an inductor directly electrically coupled to a body of the switched device and at least one of the drain of the switched device and the source of the switched device;

wherein the switched device is configured to receive a peak drain-to-source operating voltage;

wherein the switched device is characterized by a drain-to-source breakdown voltage greater than or substantially equal to the peak operating voltage; and

wherein the switched device is further characterized by a hot-carrier injection rating less than the peak operating voltage.

10. The circuit device of claim 9 , wherein the hot-carrier injection rating is a nominal operating area rating.

11. The circuit device of claim 9 , wherein the hot-carrier injection rating is a DC 0.2-year safe operating area rating.

12. The circuit device of claim 9 further comprising a switched voltage converter, the switched voltage converter including the switched device and the switch controller.

13. The circuit device of claim 9 ,

wherein the switched device is a laterally diffused metal-oxide-semiconductor (LDMOS) device; and

wherein a drift region length of the switched device determines the breakdown voltage and the hot-carrier injection rating.

14. The circuit device of claim 13 , wherein the drift region length of the switched device is less than a drift region length of a comparable switched device, the comparable switched device characterized by:

a drain-to-source breakdown voltage substantially equal to the breakdown voltage of the switched device, and

a hot-carrier injection rating greater than the peak operating voltage.

15. The circuit device of claim 9 ,

wherein the switched device is a field-effect transistor (FET) device; and

wherein a channel region length of the switched device determines the breakdown voltage and the hot-carrier injection rating.

16. The circuit device of claim 15 , wherein the channel region length of the switched device is less than a channel region length of a comparable switched device, the comparable switched device characterized by:

a drain-to-source breakdown voltage substantially equal to the breakdown voltage of the switched device, and

a hot-carrier injection rating greater than the peak operating voltage.

17. A method of designing a voltage converter, the method comprising:

determining an input voltage to be received by the voltage converter;

determining an output voltage to be produced by the voltage converter by adjusting a duty cycle of a switched device of the voltage converter;

determining a peak voltage experienced by the switched device during the duty cycle;

characterizing a typical load of the voltage converter; and

selecting a size for a drift region of the switched device for use in the voltage converter such that a drain-to-source breakdown voltage of the switched device is greater than or substantially equal to the peak voltage and a hot-carrier injection rating of the switched device is less than the peak voltage, wherein the drift region is defined by a dielectric feature and a well region of the switched device.

18. The method of claim 17 ,

wherein the switched device is a first switched device;

the method further comprising selecting a second switched device having a drain-to-source breakdown voltage greater than or substantially equal to a greater of the input voltage and the output voltage and a hot-carrier injection rating less than a greater of the input voltage and the output voltage;

wherein the first and second switched devices are part of a complimentary pair.

19. The method of claim 17 , wherein the hot-carrier injection rating is a DC 0.2-year safe operating area rating.

20. The method of claim 17 , wherein the dielectric feature is disposed between a source region of the switched device and a drain region of the switched device.