Current limiting systems and methods

Patent metadata

Field	Value
Publication number	US-9793706-B2
Application number	US-201313867964-A
Country	US
Kind code	B2
Filing date	Apr 22, 2013
Priority date	Apr 20, 2012
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

Presented systems and methods can facilitate efficient switching and protection in electronic systems. A system can comprise: an input operable to receive a signal; an adjustable component configurable to operate in a first mode which includes a low resistance and the component configurable to operate in a second mode which includes a current limiting operation in which the second mode enables continued operation in conditions that are unsafe for operation in the first mode; and an output operable to forward a signal. The adjustable component can be configurable to turn off if unsafe to operate in either the first mode or second mode. The first mode can include a relatively large component configuration with a relatively low drain to source on resistance. Utilizing a small component configuration in the second mode can include a relatively increased gate to source voltage compared to a large component configuration in the second mode.

First claim

What is claimed is:

1. A system comprising:
an input component operable to receive a signal;
a control component comprising an amplifier, a switch, a control transistor and sense transistor;
an adjustable component coupled to the input component, the adjustable component configurable to operate:
in a first mode which includes a low resistance; and
in a second mode including a current limiting operation in which the second mode enables continued operation in a condition that is unsafe for operation in the first mode, wherein the condition includes potential thermal runaway, wherein the adjustable component comprises:
a small transistor component coupled to the amplifier; and
a large transistor component coupled to the switch, wherein the large transistor component is relatively large with respect to the small transistor component;

wherein if an over-current condition is detected the switch opens disconnecting the large transistor component from the small transistor component and the sense transistor while the control transistor turns on and shorts the gate of large transistor component to the input component; and

gates of the small transistor component and the sense transistor are regulated to support a designated current limit level; and
an output component coupled to the adjustable component, the output component operable to forward a signal.

2. The system of claim 1 wherein the adjustable component is configurable to turn off when the condition becomes unsafe to operate in both the first mode and the second mode.

3. The system of claim 1 in which the first mode includes a relatively low drain to source on resistance compared to the second mode.

4. The system of claim 1 in which the second mode includes a relatively small component configuration that has an increased gate to source voltage compared to an attempt utilizing a relatively large component configuration in the second mode.

5. The system of claim 1 , wherein the control component includes:
the amplifier coupled to the input component;
a first resistor and a second resistor coupled to the amplifier;
a current source coupled to the first resistor;
the control transistor coupled to the amplifier;
the sense transistor coupled to the amplifier; and
the switch coupled to the amplifier.

6. The system of claim 5 wherein the sense transistor, the small transistor component, the large transistor component share drain connections with the gates of the sense transistor and small transistor coupled to one another.

7. The system of claim 5 wherein the amplifier is an error amp of a control loop.

8. The system of claim 5 wherein the switch is closed during normal operation and the switch connects a gate of the large transistor component to gates of the sense transistor and the small transistor component.

9. A protection process comprising:
performing a current monitoring process; and
performing a configuration process of an integrated system comprising a first transistor and second transistor, wherein the second transistor is relatively large with respect to the first transistor, wherein if an over-current condition is detected a switch opens disconnecting the second transistor from the first transistor and a sense transistor while a control transistor turns on and shorts the gate of second transistor to an input component; and gates of the first transistor and the sense transistor are regulated to support a designated current limit level, in which one configuration enables continued operation of the integrated system in conditions that are unsafe for operation in another configuration, wherein the conditions that are unsafe for operation include a potential thermal runaway within the integrated system, wherein an implementation of the one configuration and the other configuration is based upon results of the current monitoring process.

10. The protection process of claim 9 wherein the configuration process comprises:
configuring components of a device to operate in a normal mode in which a relatively large component configuration is activated or implemented;
configuring components of a device to operate in a current protection mode in which a relatively small component configuration is activated or implemented; and
configuring components of a device for operation in a third mode which includes reducing current to at least some of the components of the device.

11. The protection process of claim 10 wherein the large component configuration is implemented with a relatively low drain to source on resistance when in the on state (Rds-on) as compared to the second mode.

12. The protection process of claim 10 wherein the relatively small component configuration includes a relatively increased gate to source voltage as compared utilizing the relatively large component configuration in the current protection mode.

13. The protection process of claim 12 wherein the increased gate source voltage moves operation of the relatively small component configuration into a region of characteristics with reduced propensity for thermal run away.

14. An integrated system comprising:
an integrated control component comprising an amplifier, a switch, a control transistor and sense transistor; the integrated control component configured to control a characteristic change, including changing characteristics that enable continued operation in conditions that are unsafe for operation under different characteristics, wherein an integrated adjustable component can be dynamically changed between a normal mode configuration and a current limiting mode configuration, in which the normal mode configuration includes a low resistance characteristic and the current limiting mode configuration includes detrimental current protection and thermal run-away protection within the integrated system; and
the integrated adjustable component of the integrated system comprising:
a first transistor component coupled to an amplifier; and
a second transistor component coupled to a switch, wherein the second transistor component is relatively large with respect to the first transistor component;
wherein if an over-current condition is detected the switch opens disconnecting the second transistor component from the first transistor component and the sense transistor while the control transistor turns on and shorts the gate of second transistor component to an input component; and gates of the first transistor component and the sense transistor are regulated to support a designated current limit level.

15. The system of claim 14 wherein the integrated control component includes a control loop and the sense transistor and the integrated control component is configured to detect an adverse current condition and direct a configuration change in the integrated adjustable component to protect against the adverse current condition.

16. The system of claim 14 wherein at least some configurations of the adjustable component configurations include an interdigitated design.

Assignees

• Vishay Siliconix

Inventors

• Terrill Kyle
• Vu Trang

Classifications

• H02H9/025 Primary

  Current limitation using field effect transistors · CPC title

• H02H9/02 Primary

  responsive to excess current {(current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025)} · CPC title

• H02H3/087

  for DC applications · CPC title

• G05F1/10

  Regulating voltage or current  (G05F1/02 takes precedence) · CPC title