Output driver having improved switching delay and associated methods
AssigneeAllegro MicroSystems, LLC
InventorsDevon Fernandez, Mathew Drouin
Life of this patent
Estimating the term…
Abstract
A switching device for driving a load is provided. The switching device comprises a control terminal and has a conduction threshold which, when crossed by a control signal coupled to the control terminal, causes the switching device to conduct. A control circuit for generating the control signal is also provided. The control circuit is configured to generate a control signal having a first slew rate prior to the control signal crossing the conduction threshold and a second slew rate after the control signal has crossed the conduction threshold. The first slew rate may be faster than the second slew rate.
Claims22
An apparatus comprising:
- a switching device for driving a load, the switching device having a control terminal and a conduction threshold which, when crossed by a control signal coupled to the control terminal, causes the switching device to conduct;
- a control circuit for generating the control signal, the control signal having a first slew rate prior to the control signal crossing the conduction threshold and a second slew rate after the control signal has crossed the conduction threshold, wherein the first slew rate is faster than the second slew rate;
- an energy storage device selectively coupled to the control terminal of the switching device;
- and
- a conduction threshold reference circuit selectively coupled to the energy storage device to charge the energy storage device to a level associated with the conduction threshold.
(canceled)
A driver circuit for an output transistor having a control terminal responsive to a control signal, comprising:
- a bias circuit including an energy storage device selectively coupled to the control terminal to increase the control signal to a level associated with a conduction level of the output transistor at a first rate when the bias circuit is coupled to the control terminal, and a conduction reference threshold circuit selectively coupled to the energy storage device to charge the energy storage device to a level associated with the conduction level;
- and
- a charging circuit for increasing the control signal beyond the conduction level at a second, slower rate when the bias circuit is decoupled from the control terminal.
A method comprising:
- providing a switching device for driving a load, the switching device having a control terminal and having a conduction threshold which, when crossed by a control signal coupled to the control terminal, causes the switching device to conduct;
- charging an energy storage device by coupling the energy storage device to a conduction reference threshold circuit that charges the energy storage device to a level associated with the conduction threshold;
- ramping the level of the control signal from a first level to a level associated with the conduction threshold at a first slew rate by coupling the energy storage device to the control terminal;
- and
- ramping the level of the control signal from the conduction threshold to a second level at a second slew rate, wherein the first slew rate is faster than the second slew rate.
(canceled)
(canceled)
Dependencies are inferred from the claim text.