Adaptive duty-cycle limiting for overload protection of integrated circuits
First Claim
1. A method of adapting the current flow duty-cycle of an output driver to protect the output driver, comprising the steps of:
- sensing an overcurrent condition in the current flow of the output driver;
setting the duty-cycle of the output driver to flow the current at a given on-off duty-cycle upon sensing the overcurrent condition;
while flowing the current at the given duty-cycle, monitoring the junction temperature of the output driver; and
controlling the output driver to flow the current at a lower on-off duty-cycle, less than the given on-off duty-cycle, if the junction temperature rises above a thermal sense trip point during continuation of the sensed overcurrent condition.
1 Assignment
0 Petitions
Accused Products
Abstract
A technique for which integrated circuit duty-cycle control or pulse width current limiting adaptively responds to the load, allowing a brief inrush current event upon startup of the load, while restricting long-term power dissipation to a lower value. Upon sensing an overcurrent condition, a duty cycle control circuit causes the output to be placed into a high duty-cycle mode of operation to provide sufficient power to the load. A thermal sense circuit provides additional control because if the overcurrent condition continues and the junction temperature rises to the thermal sense trip point, the duty cycle control circuit places the output in a lower duty-cycle mode.
-
Citations
14 Claims
-
1. A method of adapting the current flow duty-cycle of an output driver to protect the output driver, comprising the steps of:
-
sensing an overcurrent condition in the current flow of the output driver;
setting the duty-cycle of the output driver to flow the current at a given on-off duty-cycle upon sensing the overcurrent condition;while flowing the current at the given duty-cycle, monitoring the junction temperature of the output driver; and controlling the output driver to flow the current at a lower on-off duty-cycle, less than the given on-off duty-cycle, if the junction temperature rises above a thermal sense trip point during continuation of the sensed overcurrent condition. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A circuit for adapting the current flow of an output driver to protect the output driver, comprising:
-
a current sense circuit connected to sense an overcurrent condition in the current flow of the output driver; a control circuit connected to the current sense circuit and connected to control the output driver to flow the current of the output driver at a given on-off duty-cycle upon sensing the overcurrent condition; and a thermal sense circuit connected to the control circuit, positioned to sense a rise in junction temperature of the output driver, and connected to cause the control circuit to flow the current of the output driver at a lower on-off duty cycle, less than the given on-off duty cycle, if the junction temperature rises above a trip of the thermal sense circuit during continuation of the sensed overcurrent condition. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
Specification