Safe Operating Area Energy Limit System and Method In Power Application

Patent metadata

Field	Value
Publication number	US-2017033552-A1
Application number	US-201615225462-A
Country	US
Kind code	A1
Filing date	Aug 1, 2016
Priority date	Jul 31, 2015
Publication date	Feb 2, 2017
Grant date	—

Abstract

A circuit protective system with an input for sensing a reference current and an input for sensing a reference voltage. The system also has circuitry for determining an estimated energy in response to the reference current and the reference voltage and circuitry for generating a control signal responsive to the estimated energy exceeding a threshold.

First claim

1 . A circuit protective system, comprising:
an input for sensing a reference current; an input for sensing a reference voltage; circuitry for determining an estimated energy in response to the reference current and the reference voltage; and circuitry for generating a control signal responsive to the estimated energy exceeding a threshold.

2 . The system of claim 1 in which the circuitry for determining includes circuitry for producing a signal having a frequency, wherein the frequency is responsive to the reference current and the reference voltage.

3 . The system of claim 1 in which the circuitry for determining includes circuitry for producing a signal having a frequency, in which the frequency is responsive to a product of the reference current and the reference voltage.

4 . The system of claim 2 in which the circuitry for determining further includes a counter for counting cycles of the signal over a first period of time.

5 . The system of claim 4 in which the circuitry for determining further includes at least one time window circuit for summing a plurality of successive counts from the counter over a second period of time greater than the first period of time.

6 . The system of claim 5 in which the circuitry for generating a control signal is for generating the control signal in response to the at least one time window circuit summing a plurality of successive counts to exceed a threshold.

7 . The system of claim 4 :
in which the circuitry for determining further includes a plurality of time window circuits, in which each time window circuit is for summing a plurality of successive counts from the counter over a respective different period of time; and in which the circuitry for generating a control signal is for generating the control signal in response to any one of the plurality of time window circuits summing a plurality of successive counts to exceed a threshold corresponding to the one of the of the plurality of time window circuits.

8 . The system of claim 7 :
in which the counter is for counting during an iteration and then resetting to count for each successive next iteration; and in which the plurality of time window circuits include:
a first time window circuit coupled to receive a count from the counter over a first number of counter iterations;
a second time window circuit coupled to receive a count from the first time window circuit over a second number of counter iterations greater than the first number of counter iterations; and
a third time window circuit coupled to receive a count from the second time window circuit over a third number of counter iterations greater than the first number of counter iterations.

9 . The system of claim 8 and further including:
an accumulator for receiving and summing successive counts from the third time window circuit; and
circuitry for periodically decrementing the accumulator.

10 . The system of claim 9 wherein the circuitry for generating a control signal is for generating the control signal in response to a sum in the accumulator exceeding the threshold.

11 . The system of claim 10 and further including circuitry for disabling flow of the reference current in response to the control signal when the estimated energy exceeds the threshold.

12 . The system of claim 11 in which the threshold includes a first threshold, and further including circuitry for re-enabling flow of the reference current, after disabling flow of the reference current, in response to the control signal and when the estimated energy falls below a second threshold.

13 . The system of claim 10 and further including circuitry for disabling flow of the reference current in response to the control signal when the estimated energy exceeds the threshold and for a duration until the accumulator is decremented to a count of zero.

14 . The system of claim 4 wherein the counter includes a Gray code counter.

15 . The system of claim 1 and further including circuitry for disabling flow of the reference current in response to the control signal when the estimated energy exceeds the threshold.

16 . The system of claim 1 and further including a transistor having a gate coupled to be selectively enabled and disabled in response to the control signal and for conducting the reference current when enabled.

17 . The system of claim 16 and further including a load coupled to the transistor and for receiving a current when the transistor is enabled.

18 . The system of claim 17 wherein the load includes an incandescent bulb.

19 . A circuit protective system, comprising:
a first terminal to connect to a first node; a second terminal to connect to a second node; current determining circuitry determining a reference current between the first node and the second node; a third terminal to connect to a third node; voltage determining circuitry determining a reference voltage between the third node and another node; energy determining circuitry estimating energy in response to the reference current and the reference voltage; and control signal circuitry generating a control signal responsive to the estimated energy exceeding a threshold.

20 . The system of claim 19 in which the energy determining circuitry includes waveform circuitry producing a signal having a frequency, in which the frequency is responsive to a product of the reference current and the reference voltage.

Assignees

• Texas Instruments Inc

Inventors

• Aras Sualp
• Quirk Adam
• Rahman Md Abidur

Classifications

• H02H3/06

  with automatic reconnection · CPC title

• H02H3/006

  Calibration or setting of parameters · CPC title

• H02H3/38 Primary

  responsive to both voltage and current; responsive to phase angle between voltage and current · CPC title

• H02H3/42 Primary

  responsive to product of voltage and current · CPC title

• H02H3/027

  with automatic disconnection after a predetermined time (H02H3/033, H02H3/06 take precedence {; timing in overcurrent protection circuits H02H3/093; in undervoltage protection circuits H02H3/247; staggered disconnection H02H7/30}) · CPC title