Switching circuits

• US 7,034,609 B2
• Filed: 11/12/2003
• Issued: 04/25/2006
• Est. Priority Date: 11/12/2003
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Risbo, Lars, Josefsen, Anker
• Primary Examiner(s): Nguyen, Khanh V.
• Application Number:
  US10/712,746
• Publication Number:
  US 20050099226A1
• Time in Patent Office: 895 Days
• Field of Search: 330/10, 330/207.A, 330/251
• US Class Current: 330/10
• CPC Class Codes: H03F 2203/45636 the LC comprising clamping means, e.g. diodes
• CPC Class Codes: H03F 3/217 Class D power amplifiers; Switching amplifiers
• CPC Class Codes: H03F 3/45085 Long tailed pairs H03F3/45112, H03F3/45139 take precedence

Abstract

A technique to implement removal of dead time control circuitry from the back-end of a digital switching amplifier system 100 and add dead time control circuitry on the front-end digital modulator chip. The front-end dead time control circuitry adaptively adjusts timing of the output PWM control signals 124 to optimize performance and power consumption, i.e. operate with minimum dead time for all transitions. The front-end dead time control circuitry controls all propagation delays associated with the digital switching amplifier system 100.

Claims

1. A switching amplifier controller comprising:

a switching output stage comprising an Hbridge having 4 power switches configured to drive a load in a bridge tied configuration;

a shoot through detector operative to detect shoot through generated by the switching output stage and generate a shoot through signal in response thereto;

a shoot through encoder operative to generate a shoot through feedback signal in response to the shoot through signal;

an adaptation controller operative to generate adaptive control signals in response to the shoot through feedback signal;

a timing controller operative to generate a first set of timing control signals in response to a PWM input signal and the adaptive control signals;

a signal combiner operative to generate a second set of timing control signals in response to the first set of timing control signals; and

a plurality of power switch drivers operative to generate power switch turn-on signals and power switch turn-off signals in response to the second set of timing control signals to control power switch turn-on and turn-off switching transitions such that dead time associated with the switching transitions is substantially eliminated and further such that shoot through is negated during switching transitions subsequent to detection of shoot through via the shoot through detector.

2. The switching amplifier controller according to claim 1 wherein the shoot through detector configured to assist the timing controller resolve the turn-on and turn-off switching transitions such that shoot through is negated during the switching transitions.

3. The switching amplifier controller according to claim 1 wherein the timing controller is an adaptive timing controller that operates in response to a shoot through feedback signal generated by the switching output stage such that shoot through is negated during the switching transitions.

4. The switching amplifier controller according to claim 1 wherein the timing controller is further configured to prevent switching output stage shoot through during the switching transitions.

5. A switching amplifier controller comprising:

a switching output stage; and

means for controlling turn-on and turn-off switching transitions associated with the switching output stage in reaponse to a shoot through feedback signal caused by switching output stage shoot through, such that dead time associated with the switching transitions is substantially eliminated and further such that shoot through is negated during the switching transitions subsequent to a switching transition exhibiting shoot through,

wherein the means for controlling turn-on and turn-off switching transitions cormpises;

a shoot through detector operational to detect switching output stage shoot through and generate an output signal in response thereto; and

an encoder operational to generate the shoot through feedback signal in response to the shoot through detector output signal,

wherein the means for controlling turn-on and turn-off switching transitions further comprises;

an adaptation controller operative to generate adaptive control signals in response to the shoot through feedback signal;

a timing controller operative to generate a first set of timing control signals in response to a PWM input signal and the adaptive control signals;

a signal combiner operative to generate a second set of timing control signals in response to the first set of timing control signals; and

a plurality of switch drivers operative to generate switching output stage turn-on signals and switching output stage turn-off signals in response to the second set of timing control signals to control switch turn-on and turn-off switching transitions.