Patent Grant
7049798
1. Field of the Invention
The present invention relates to controlling a point-of-load (“POL”) regulator, or more particularly, to a system and method of utilizing a POL control unit to program and/or monitor a POL regulator.
2. Description of Related Art
Point-of-load (“POL”) regulators, which are also referred to as voltage regulators or DC/DC converters, are commonly used in conjunction with electronic circuits. This is because the voltage/current requirements of electronic circuits typically differ from the voltage that is readily available or the current that can practically be delivered. For example, some electronic devices only include a single voltage input (e.g., 12 v), but require different voltages for circuits contained within (e.g., 3 v, 5 v, 9 v, etc.). A common solution is to design multiple POL regulators within the device for converting the single input voltage into multiple voltage levels.
Similarly, some electronic devices include circuits that require low voltage (e.g., 1 v), high current (e.g., 100 A) power supplies. This is problematic in that it is impractical to deliver high current at low voltage levels over a relatively long distance and still meet desired regulation performances. A common solution is to use a high voltage, low current power supply and design a POL regulator near the internal circuit. This allows low current to travel throughout the device, and provides a low voltage, high current power supply (i.e., using the POL regulator) near the internal circuit.
Traditionally, POL regulators operate in conjunction with at least one power supply controller. The controller activates and partially programs the POL regulator by providing data directly to the POL regulator, and monitors the POL regulator by measuring data external to the POL regulator. Specifically, the controller provides the POL regulator with output-voltage-set-point data and enable data. The POL regulator, which has been manually pre-programmed (e.g., hard wired, etc.) to produce a particular current level, produces an output having a voltage level in accordance with the output-voltage-set-point data. The output of the POL regulator passes through a current sense resistor and a transistor switch connected in series with a load circuit. The controller, through its connections to the current sense resistor and the output terminal of the POL regulator, is then able to measure the output voltage/current that is being delivered by the POL regulator. If the output voltage or current exceeds a known value, the controller can disable the POL regulator by communicating directly with the POL regulator or disconnecting the load by opening the transistor switch.
The drawback with such a control system is that it adds complexity, expense and size to the control system by requiring the controller to communicate with multiple devices (e.g., a POL regulator and an external circuit) to program and monitor the POL regulator. Such a system also limits the type of programming and monitoring that can be performed. Thus, it would be advantageous to have a system and method of programming and/or monitoring a POL regulator that overcomes these drawbacks.
The present invention provides a system and method of utilizing a point-on-load (“POL”) control unit for programming and/or monitoring a POL regulator. Embodiments of the present invention operate in accordance with a power supply controller (“controller”) and at least one POL regulator, each POL regulator including a control unit and a storage device. Specifically, the controller is adapted to provide initial-configuration data to each POL regulator. The initial-configuration data, which may include output-voltage-set-point-data (i.e., a desired output voltage), output-current-set-point data (i.e., the highest desired output current), low-voltage-limit data (i.e., the lowest desired output voltage), high-voltage-limit data (i.e., the highest desired output voltage), output-voltage-slew-rate data (i.e., the desired output slew rate), enable/disable data (i.e., turning on/off the POL regulator output), and/or other POL programming data (e.g., voltage, current, temperature, timing data), is then received by the POL control unit and stored in the storage device. At least a portion of the initial-configuration data is then used to produce a desired output of the POL regulator.
The POL control unit is also adapted to store fault-monitoring data in the storage device and provide at least a portion of the fault-monitoring data to the controller. If the provided portion of the fault-monitoring data, which may include output-voltage data (e.g., actual-output-voltage data, voltage-comparison data, etc.), output-current data (e.g., actual-output-current data, current-comparison data, etc.), temperature-status data (e.g., actual-temperature data, temperature-comparison data, etc.), and/or other POL fault monitoring data, violates a known parameter, the controller may respond by performing a particular action (e.g., disable the POL regulator, closely monitor a particular parameter, store the provided portion of fault-monitoring data, notify an administrator, etc.). In another embodiment of the present invention, the POL control unit is also adapted to respond to a violation by performing a particular action (e.g., disabling the POL regulator, notifying the controller, etc.).
In another embodiment of the present invention, the POL regulator further includes at least one sensor circuit. The sensor circuit, which may be adapted to detect voltage levels, current levels, temperature levels, etc., is used to produce the fault-monitoring data (either alone or in conjunction with information stored in the storage device).
In another embodiment of the invention, the initial-configuration data and the fault-monitoring data are transmitted over a bi-directional serial data bus (either synchronously or asynchronous). In other words, the bi-directional serial data bus is either a two-wire serial bus (e.g., I2C) that allows data to be transmitted asynchronously or a single-wire serial data bus that allows data to be transmitted synchronously (i.e., synchronized to a clock signal). In another embodiment of the present invention, the serial data bus (or a portion thereof is superimposed over (or coexistent with) a power bus used to deliver power from a front-end converter to the POL regulator.
A more complete understanding of the system and method of utilizing a POL control unit to program and/or monitor a POL regulator will be afforded to those skilled in the art, as well as a realization of additional advantages and objects thereof, by a consideration of the following detailed description of the preferred embodiment. Reference will be made to the appended sheets of drawings which will first be described briefly.
The present invention provides a system and method of utilizing a point-on-load (“POL”) control unit to program and/or monitor a POL regulator. In the detailed description that follows, like element numerals are used to describe like elements illustrated in one or more figures.
As shown in
The problem with such a control system 10 is that it adds complexity, expense and size to the overall electronic device (not shown) by requiring the controller 110 to communicate with multiple devices (e.g., converter 140 and external circuit R1, S1) in order to program and monitor a particular DC/DC converter (e.g., 140). Such a control system 10 also limits the type of programming and monitoring that can be performed. For example, while the output voltage level of the DC/DC converter can be programmed via the six bit parallel bus, other parameters (e.g., maximum output current, slew rate, etc.) need to be manually selected (e.g., hard wired, etc.). Furthermore, while the output voltage/current level of the DC/DC converter can be monitored via the three-wire output connection, additional parameters (e.g., temperature status, etc.) cannot be monitored without additional circuitry and/or connections.
In one embodiment of the present invention, as shown in
Referring to FIGS. 2 and 3-1, the controller 210 is adapted to provide initial-configuration data to each POL regulator (i.e., 220, 230, 240, 250). It should be appreciated that the initial-configuration data may include, but is not limited to, one or more of the following: output-voltage-set-point-data (i.e., a desired output voltage); output-current-set-point data (i.e., the highest desired output current); low-voltage-limit data (i.e., the lowest desired output voltage); high-voltage-limit data (i.e., the highest desired output voltage); output-voltage-slew-rate data (i.e., the desired output slew rate); enable/disable data (i.e., turning on/off the POL regulator output); timing data (e.g., turn-on delay, turn-off delay, fault recovery time, etc.) and/or all other types of POL programming data generally known to those skilled in the art. Once the initial-configuration data is received, the POL control unit 310 is adapted to store at least a portion of the initial-configuration data in the storage device 320. For example, if the storage device 320 is a plurality of registers, the output-voltage-set-point data may be stored in an output-voltage-set-point register, the output-current-set-point data may be stored in an output-current-set-point register, the low-voltage-limit data and the high-voltage data may be stored in a protection configuration register, and the enable/disable data may be stored in a status register. At least a portion of the stored initial-configuration data is then used to produce a desired output. For example, an output may be produced to include a particular voltage level, a particular slew rate, etc.—depending on the type of initial-configuration data received/stored.
After the output has been produced, the POL control unit 310 is adapted to receive fault-monitoring data (e.g., from an external device, a sense circuit, etc.). The fault-monitoring data, which contains information on the POL regulator or its output, is then stored in the storage device 320. The POL control unit 310, in response to a condition (e.g., receiving a request, exceeding a known parameter, having a register's contents change, etc.), is then adapted to provide at least a portion of the fault-monitoring data to the controller 210. It should be appreciated that the fault-monitoring data may include, but is not limited to, one or more of the following: output-voltage data, which may include actual-output-voltage data (i.e., the measured output voltage) or voltage-comparison data (e.g., whether the measured output voltage is above or below the highest desired output voltage, whether the measured output voltage is above or below the lowest desired output voltage, etc.); output-current data, which may include actual-output-current data (i.e., the measured output current) or current-comparison data (e.g., whether the measured output current is above or below the highest desired output current); temperature-status data, which may include actual-temperature data (i.e., the measured temperature of a POL regulator, or more particularly its heat generating components) or temperature-comparison data (e.g., whether the temperature of the POL regulator (or its components) is above or below a known value, etc.), and/or all other types of POL fault monitoring data generally known to those skilled in the art. It should also be appreciated that fault-monitoring data is not limited to data representing the existence of a faulty condition. For example, fault-monitoring data that indicates that the POL regulator is operating within acceptable parameters (e.g., within an acceptable temperature range) is within the spirit and scope of the present invention.
The fault-monitoring data can be used by either the controller 210 or the control unit 310 to monitor and/or control the POL regulator. In other words, the control unit 310 can use the fault-monitoring data to either provide POL status information (i.e., data corresponding to a particular POL regulator or its output) to the controller 210 or disable the POL regulator if a particular condition is met (e.g., the status register changes; the temperature limit has been exceeded, etc.). Alternatively, the controller 210 can use the fault-monitoring data to either provide POL status information to an administrator, disable a particular POL regulator, or store the fault-monitoring data for future use. For example, in one embodiment of the present invention, each POL regulator includes unique ID data (e.g., serial number, date of manufacture, etc.) stored in an ID register. This enables the controller 210 to provide POL status information and unique ID data to an administrator.
In another embodiment of the present invention, as shown in
While the initial-configuration data and the fault-monitoring data can be transmitted via a parallel bus, one embodiment of the present invention involves transmitting the initial-configuration data and the fault-monitoring data over a bi-directional serial data bus (either synchronously or asynchronous). In other words, the bi-directional serial bus is either a two-wire serial data bus (e.g., I2C) that allows data to be transmitted asynchronously or a single-wire serial data bus that allows data to be transmitted synchronously (i.e., synchronized to a clock signal). In another embodiment of the present invention the serial data bus (or a portion thereof) is superimposed over (or coexistent with) a power bus used to deliver power from the front-end converter to the POL regulators.
The first and second acknowledgement bits 540, 570 are used to acknowledge the reception of the command set 530 and the data set 560, respectively. It should be appreciated that the device responsible for the providing the first and second acknowledgement bits 540, 570 varies depending upon whether the information is being sent to or from the POL regulator (i.e., whether the information is being written, read, or provided).
The command set 530, data set 560, and address set 520 enable the controller and the POL regulators to write, read and provide data. Specifically, (i) the command set 530 is used to identify whether and what the controller is writing (e.g., writing to the status register), the controller is reading (e.g., reading the status register), or the POL regulator is providing (e.g., providing status register information), (ii) the address set 520 is used to identify the POL regulator(s) that is being written to or read, or the POL regulator that is providing information, and (iii) the data set 560 is used to identify the actual data that is being written, read, or provided.
The start sequence 510 and address set 520 are used, in part, to identify the sender of the information. For example, the controller uses a different start sequence 510 than the POL regulators. Thus, the controller can determine, by reading the start sequence 510 of the communication cycle 50 being transmitted, whether a POL regulator is also attempting to send a communication cycle 50 at the same time. Similarly, each POL regulator has a different address set 520. Thus, a POL regulator can determine, by reading the start sequence 510 and address set 520 of the communication cycle 50 being transmitted, whether another POL regulator or the controller is also attempting to send a communication cycle 50 at the same time. If multiple devices are attempting to send a communication cycle 50, sequencing data is used to allocate or arbitrate bus use. It should be appreciated that the sequence data can either be stored (or hard wired) as a default value or provided as initial-configuration data and stored in the storage device (e.g., a sequencing configuration register).
One method of providing/utilizing initial-communication data is illustrated in
One method of providing/utilizing fault-monitoring data is illustrated in
In another embodiment of the invention, the fault-monitoring data itself indicates whether a monitored parameter violates a known parameter. For example, if output-current-set-point data (i.e., the highest desired output current) is received as initial-configuration data and stored in the storage device, the POL regulator (or more particular the POL control unit) can provide the controller with fault-monitoring data that indicates whether the measured output current is over or under the stored maximum current value. In this instance, if the received fault-monitoring data indicates that the output current is below the maximum value, the controller can continue to monitor the POL regulator as previously described. Alternatively, if the received fault-monitoring data indicates that the output current is above the maximum value, the controller (without making any additional calculations) can disable the POL regulator.
Having thus described a preferred embodiment of a system and method of controlling a point-of-load regulator, it should be apparent to those skilled in the art that certain advantages of the system have been achieved. It should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made within the scope and spirit of the present invention. The invention is further defined by the following claims.
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