Multiphase resonant pulse generators

• US 7,202,712 B2
• Filed: 05/30/2006
• Issued: 04/10/2007
• Est. Priority Date: 08/10/2000
• Status: Expired due to Fees

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Athas, William C.
• Primary Examiner(s): Callahan; Timothy P.
• Assistant Examiner(s): Nguyen; Hiep
• Application Number:
  US11/420,950
• Publication Number:
  US 20070057706A1
• Time in Patent Office: 315 Days
• Field of Search: None
• US Class Current: 327/129
• CPC Class Codes: H03B 27/00 Generation of oscillations providing a plurality of outputs of the same frequency but differing in phase, other than merely two anti-phase outputs
• CPC Class Codes: H03B 5/1215 the current source or degeneration circuit being in common to both transistors of the pair, e.g. a cross-coupled long-tailed pair
• CPC Class Codes: H03B 5/1228 the amplifier comprising one or more field effect transistors
• CPC Class Codes: H03K 3/03 Astable circuits
• CPC Class Codes: H03K 3/354 Astable circuits

Abstract

A multiphase resonant pulse generator (74) has N groups of N−1 switches (44,46,48) which, when activated, form N paths from a power supply (Vdc) to ground or a reference voltage. Here N is a positive integer greater than 2. Each of the paths includes an inductance (38,40,42) and N−1 switches. The signal outputs (X1,X2,X3) from each of the N paths are cross coupled to switches belonging to the other N−1 paths to active or deactivate the groups of switches.

Claims

1. A pulse generating circuit comprising:

a tank circuit configured to resonate; and

a control circuit coupled to the tank circuit and configured to cause the tank circuit to produce a stream of substantially sinusoidal shaped resonant periodic pulses that substantially conform to a graph comprising a unit circle and two tangents to the circle that intersect the circle at points A and B, respectively, and that intersect each other at a point C,

wherein the longer arc on the circle between the point A and the point B represents the interval between the pulses,

wherein the distance from the point A to the point C plus the distance from the point B to the point C represents the off interval between the pulses,

wherein tan

$\mathrm{\theta <br><br>}=\frac{r}{\left(\frac{\mathrm{\pi <br><br>}}{2}+\mathrm{\theta <br><br>}\right)},$

and

wherein θ

is one-half of the angle BCA and wherein r is the length of the longer arc and is not equal to unity.

2. The circuit of claim 1, wherein the control circuit includes a switch configured to clamp a voltage generated by the pulse generating circuit to a substantially constant value thereby producing the off interval.

3. The circuit of claim 2, wherein the tank circuit includes an inductance and wherein the control circuit is configured to cause the switch to only activate when the current flow through the inductance is of the opposite polarity of the forward current through an input voltage source, the inductance, and a reference voltage.

4. The circuit of claim 3, wherein the control circuit is configured to deactivate the switch when the current and voltage of the tank circuit have a phase difference of approximately 90 degrees relative to each other.

5. The circuit of claim 2, wherein the control circuit is configured to cause the switch to prevent the stream of pulses which it clamps from reversing in polarity.

6. The circuit of claim 1, wherein the pulse generating circuit generates an input reference voltage of approximately zero.

7. The circuit of claim 6, wherein the pulse generating circuit generates an input direct current voltage less than the reference voltage.

8. The circuit of claim 6, wherein the pulse generating circuit generates an input direct current voltage greater than the input reference voltage.

9. The circuit of claim 1, wherein the control circuit includes a MOSFET.

10. A method of generating pulses comprising:

alternately activating and deactivating a switch electrically connected to an input voltage source, a reference voltage source and a load so as to generate a stream of substantially sinusoidal shaped resonant periodic pulses that substantially conform to a graph comprising a unit circle and two tangents to the circle that interest the circle at points A and B, respectively, and that interest each other at a point C,

wherein the longer arc on the circle between the point A and the point B represents the interval between the pulses,

wherein the distance from the point A to the point C plus the distance from the point B to the point C represents the off interval between the pulses,

wherein

$r=\frac{\mathrm{arc}<br><br><br><br>\mathrm{lenght}<br><br><br><br>A<br><br><br><br>B}{\mathrm{segment}<br><br><br><br>B<br><br><br><br>C+\mathrm{segment}<br><br><br><br>A<br><br><br><br>C},$

and

wherein r is not equal to unity.

11. The method for generating pulses of claim 10, further comprising clamping a voltage to a substantially constant value to produce the off interval.

12. The method for generating pulses of claim 11, wherein the voltage is first clamped when a current flow through an inductance is of the opposite polarity of the forward current through a path formed by an input voltage source, the inductance, and a reference voltage source.

13. The method for generating pulses of claim 12 further comprising removing the clamping when the current and voltage of a tank circuit containing the inductance resonate and have a phase difference of approximately 90 degrees relative to each other.

14. The method for generating pulses of claim 11, wherein the clamping prevents the stream of pulses from reversing in polarity.

15. A pulse generating circuit comprising:

a means for producing a stream of substantially sinusoidal shaped resonant periodic pulses that substantially conform to a graph comprising a unit circle and two tangents to the circle that intersect at points A and B, respectively, and that intersect each other at a point C,

wherein the longer arc on the circle between the point A and the point B represents the interval between the pulses,

wherein the distance from the point A to the point C plus the distance from the point B to the point C represents the off interval between the pulses;

wherein

$r=\frac{\mathrm{arc}<br><br><br><br>\mathrm{lenght}<br><br><br><br>A<br><br><br><br>B}{\mathrm{segment}<br><br><br><br>B<br><br><br><br>C+\mathrm{segment}<br><br><br><br>A<br><br><br><br>C},$

and

wherein r is not equal to unity.