Automatic detection of a CMOS device in latch-up and cycling of power thereto
A monitoring and protection circuit associated with a voltage regulator supplying power to a CMOS device can sense over current levels precisely enough for determining if a fault has occurred in a circuit of the CMOS device, e.g., latch-up, failed or shorted transistor, etc., then this monitoring and protection circuit may automatically generate a fault alert signal and/or cycle power to the CMOS device when an unexpected over current may occur, e.g., CMOS circuit latch-up. The monitoring and protection circuit may be integrated with a voltage regulator, e.g., low drop-out (LDO) voltage regulator on a single integrated circuit substrate. The monitoring and protection circuit and voltage regulator may be fabricated with a CMOS device, e.g., digital processor on a single integrated circuit substrate.
1. A system for monitoring and protection of a complementary metal oxide semiconductor (CMOS) device, said system comprising:
a complementary metal oxide semiconductor (CMOS) device;
a current measurement circuit for measuring current therethrough and adapted for coupling to a power source, the current measurement circuit having a measured current output;
a power switching circuit coupled to the current measurement circuit and having an output for supplying power to the CMOS device;
a regulator control circuit coupled to the power switching circuit, the regulator control circuit controlling a voltage at the output of the power switching circuit;
a comparator having a first input coupled to the measured current output of the current measurement circuit;
a current trip set point circuit having an input coupled to the CMOS device and a first output coupled to a second input of the comparator, wherein the CMOS device sends device configuration information to the current trip set point circuit for determining a high current trip set point;
the comparator having an output coupled to the power switching circuit that causes the power switching circuit to operate normally as a voltage regulator with the regulator control circuit when the comparator output is at a first logic level, and to shut down the power switching circuit when the comparator output is at a second logic level, thereby cycling power on and off to the CMOS device,
wherein the comparator output is at the first logic level when the measured current from the current measurement circuit is less than the high current trip set point, and is at the second logic level when the measured current is greater than or equal to the high current trip set point; and
a watchdog timer coupled to the power switching circuit and to the CMOS device, wherein the watchdog timer will shut down the power switching circuit if an expected signal from the CMOS device is not received within a certain time period, otherwise the watchdog timer allows the power switching circuit to operate normally as the voltage regulator with the regulator control circuit.
2. The system of claim 1 , further comprising the current trip set point circuit having a second output coupled to a third input of the comparator, wherein the current trip set point circuit further determines a low current trip set point, whereby the comparator output is at the first logic level when the measured current from the current measurement circuit is greater than the low current trip set point, and is at the second logic level when the measured current is less than or equal to the low current trip set point.
3. The system of claim 2 , further comprising the CMOS device sending application configuration information to the current trip set point circuit for determining the low current trip set point.
4. The system of claim 2 , wherein the low current trip set point is programmable by the CMOS device.
5. The system of claim 2 , wherein the power switching circuit and current trip set point circuit comprise an under current protection circuit.
6. The system of claim 1 , further comprising the CMOS device sending application configuration information to the current trip set point circuit for determining the high current trip set point.
7. The system of claim 6 , wherein the current measurement circuit, the power switching circuit, the regulator control circuit, the comparator, the current trip set point circuit and the watchdog timer are fabricated on a semiconductor integrated circuit die.
8. The system of claim 7 , wherein the semiconductor integrated circuit die is enclosed in an integrated circuit package.
9. The system of claim 6 , wherein the current measurement circuit, the power switching circuit, the regulator control circuit, the comparator, the current trip set point circuit, the watchdog timer and CMOS device are fabricated on a semiconductor integrated circuit die.
10. The system of claim 9 , wherein the semiconductor integrated circuit die is enclosed in an integrated circuit package.
11. The system of claim 1 , wherein the high current trip set point is programmable by the CMOS device.
12. The system of claim 1 , wherein the power switching circuit stays off for a certain off-time before turning back on.
13. The system of claim 12 , wherein the certain off-time is long enough for the CMOS device to un-latch before power is reapplied thereto.
14. The system of claim 1 , wherein the current measurement circuit, the power switching circuit, the regulator control circuit, the comparator and the current trip set point circuit are fabricated on a semiconductor integrated circuit die.
15. The system of claim 14 , wherein the semiconductor integrated circuit die is enclosed in an integrated circuit package.
16. The system of claim 1 , wherein the current measurement circuit, the power switching circuit, the regulator control circuit, the comparator, the current trip set point circuit and the CMOS device are fabricated on a semiconductor integrated circuit die.
17. The system of claim 16 , wherein the semiconductor integrated circuit die is enclosed in an integrated circuit package.
18. The system of claim 1 , wherein the power switching circuit and the regulator control circuit form a low dropout (LDO) voltage regulator.
19. The system of claim 1 , wherein the CMOS device is a digital processor.
20. The system of claim 19 , wherein the digital processor is a microcontroller.
21. The system of claim 19 , wherein the digital processor is selected from the group consisting of a microcomputer, a digital signal processor (DSP), an application specific integrated circuit (ASIC), and a programmable logic array (PLA).
22. The system of claim 1 , wherein the power switching circuit and current trip set point circuit comprise an over current protection circuit.
23. A system for monitoring and protection of a voting triad of complementary metal oxide semiconductor (CMOS) devices, said system comprising:
first, second and third complementary metal oxide semiconductor (CMOS) devices; and
first, second and third voltage regulators supplying regulated power that is capable of being cycled to the respective first, second and third CMOS devices;
wherein the first, second and third CMOS devices communicate with each other for determining operational health for each thereof;
each of the first, second and third voltage regulators comprising:
a current measurement circuit for measuring current therethrough and adapted for coupling to a power source, the current measurement circuit having a measured current output;
a power switching circuit coupled to the current measurement circuit and having an output for supplying power to a respective one of the first, second and third CMOS devices;
a regulator control circuit coupled to the power switching circuit, the regulator control circuit controlling a voltage at the output of the power switching circuit;
a comparator having a first input coupled to the measured current output of the current measurement circuit;
a current trip set point circuit having an input coupled to a respective one of the first, second and third CMOS devices and a first output coupled to a second input of the comparator, wherein the respective one of the first, second and third CMOS devices sends device configuration information to the current trip set point circuit for determining a high current trip set point; and
the comparator having an output coupled to the power switching circuit that causes the power switching circuit to operate normally as a voltage regulator with the regulator control circuit when the comparator output is at a first logic level, and to shut down the power switching circuit when the comparator output is at a second logic level, thereby cycling power on and off to the respective one of the first, second and third CMOS devices,
wherein the comparator output is at the first logic level when the measured current from the current measurement circuit is less than the high current trip set point, and is at the second logic level when the measured current is greater than or equal to the high current trip set point;
wherein the power switching circuit of a one of the first, second and third CMOS devices shuts down when the other two of the first, second and third CMOS devices do not receive an expected communication from the one of the first, second and third CMOS devices.
24. A system for monitoring and protection of a complementary metal oxide semiconductor (CMOS) device, said system comprising:
a complementary metal oxide semiconductor (CMOS) device;
a current measurement circuit for measuring current therethrough and adapted for coupling to a power source, the current measurement circuit having a measured current output;
a power switching circuit coupled to the current measurement circuit and having an output for supplying power to the CMOS device;
a regulator control circuit coupled to the power switching circuit, the regulator control circuit controlling a voltage at the output of the power switching circuit;
a comparator having a first input coupled to the measured current output of the current measurement circuit;
a current trip set point circuit having an input coupled to the CMOS device and a first output coupled to a second input of the comparator, wherein the CMOS device sends device configuration information to the current trip set point circuit for determining a high current trip set point;
the comparator having an output coupled to the power switching circuit that causes the power switching circuit to operate normally as a voltage regulator with the regulator control circuit when the comparator output is at a first logic level, and to shut down the power switching circuit when the comparator output is at a second logic level, thereby cycling power on and off to the CMOS device,
wherein the comparator output is at the first logic level when the measured current from the current measurement circuit is less than the high current trip set point, and is at the second logic level when the measured current is greater than or equal to the high current trip set point; and
a communications bus adapted for communicating with at least one other CMOS device, wherein if the at least one other CMOS device does not receive an expected signal from the CMOS device on the communications bus, then the at least one other CMOS device causes the power switching circuit to shut down, thereby cycling power on and off to the CMOS device.
25. A system for monitoring and protection of a complementary metal oxide semiconductor (CMOS) device, said system comprising:
a complementary metal oxide semiconductor (CMOS) device;
a current measurement circuit for measuring current therethrough and adapted for coupling to a power source, the current measurement circuit having a measured current output;
a power switching circuit coupled to the current measurement circuit and having an output for supplying power to the CMOS device;
a regulator control circuit coupled to the power switching circuit, the regulator control circuit controlling a voltage at the output of the power switching circuit;
a comparator having a first input coupled to the measured current output of the current measurement circuit;
a current trip set point circuit having an input coupled to the CMOS device and a first output coupled to a second input of the comparator, wherein the CMOS device sends device configuration information to the current trip set point circuit for determining a high current trip set point;
the comparator having an output coupled to the power switching circuit that causes the power switching circuit to operate normally as a voltage regulator with the regulator control circuit when the comparator output is at a first logic level, and to shut down the power switching circuit when the comparator output is at a second logic level, thereby cycling power on and off to the CMOS device,
wherein the comparator output is at the first logic level when the measured current from the current measurement circuit is less than the high current trip set point, and is at the second logic level when the measured current is greater than or equal to the high current trip set point; and
two communications buses adapted for communicating with two other CMOS devices, wherein if the two other CMOS devices do not receive expected signals from the CMOS device on the two communications buses, then the two other CMOS devices cause the power switching circuit to shut down, thereby cycling power on and off to the CMOS device.