Patent Application
20140333287
The present invention relates generally to integrated circuits, and more particularly, to a system for measuring power consumption of an integrated circuit.
An integrated circuit (IC) includes electronic components including processors, memories and interface circuits. The IC further has software programs installed on these electronic components to enable them to perform predefined functions. Examples of software programs include system software programs and application software programs. System software programs control and operate the electronic components, whereas application software programs facilitate a user to perform specific functions/tasks using the IC.
The overall power consumption of the IC depends on the power consumption of the electronic components, which in turn largely depends on the software programs within. The effect of electronic components and system software programs on the power consumption is determined and optimized during IC design and testing phase. However, effect of an application software program on the power consumption can be determined only when the IC executes the application software program when it is in a high power mode. The power consumption of the IC during the high power mode is measured using external current probes, and is monitored using external low voltage detectors.
However, use of external current probes and low voltage detectors increases the overall cost of operation of the IC and cannot determine effect of an application software program on the power consumption, as the current probes cannot identify coding instructions of the application software program that cause excessive power consumption. The current probes further are not effective in optimizing an application software program based on power consumption, when the IC executes the application software program.
Hence, there is a need for a system for measuring power consumption of an IC that does not require external current probes and low voltage detectors, that accurately determines the effect of an application software program on the power consumption, that optimizes the power consumption, and that overcomes the above-mentioned limitations of existing ICs.
The following detailed description of the preferred embodiments of the present invention will be better understood when read in conjunction with the appended drawings. The present invention is illustrated by way of example, and not limited by the accompanying figures, in which like references indicate similar elements. It is to be understood that the drawings are not to scale and have been simplified for ease of understanding the invention.
The detailed description of the appended drawings is intended as a description of the currently preferred embodiments of the present invention, and is not intended to represent the only form in which the present invention may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present invention.
In an embodiment of the present invention, an integrated circuit is provided that includes a plurality of electronic components, a voltage regulator connected to the plurality of electronic components, and a power consumption measurement module. The voltage regulator includes a voltage regulator controller, connected to an input power supply for receiving an input supply voltage and generating a control voltage. The voltage regulator further includes a voltage driver that has a gate terminal connected to an output of the voltage regulator controller for receiving the control voltage, a source terminal connected to the input power supply for receiving the input supply voltage, and a drain terminal connected to the plurality of electronic components for providing a regulated voltage thereto. The power consumption measurement module is connected to the gate terminal of the voltage driver, and includes an analog-to-digital converter (ADC),an averaging module connected to the ADC, and a current profiling module connected to the averaging module. The ADC receives and samples the control voltage and generates a plurality of digital control voltage samples. The averaging module receives and averages the plurality of digital control voltage samples to generate an averaged control voltage data. The current profiling module receives the averaged control voltage data and determines an average current, wherein the average current represents power consumption of the integrated circuit.
In another embodiment of the present invention, an integrated circuit is provided that includes a plurality of electronic components, a voltage regulator connected to the plurality of electronic components, and a power consumption measurement module. The voltage regulator includes a voltage regulator controller, connected to an input power supply for receiving an input supply voltage and generating a control voltage. The voltage regulator further includes a voltage driver having a gate terminal connected to an output of the voltage regulator controller for receiving the control voltage, a source terminal connected to the input power supply for receiving the input supply voltage, and a drain terminal connected to the plurality of electronic components for providing a regulated voltage thereto. The power consumption measurement module is connected to the gate terminal of the voltage driver, and includes a unity gain buffer for receiving and buffering the control voltage, an analog-to-digital converter (ADC) connected to the unity gain buffer, an averaging module connected to the ADC, a control register connected to the averaging module, and a current profiling module connected to the control register. The ADC receives and samples the control voltage to generate a plurality of digital control voltage samples. The averaging module receives and averages the plurality of digital control voltage samples to generate an averaged control voltage data. The control register receives and stores the averaged control voltage data. The current profiling module receives the averaged control voltage data, and determines an average current, wherein the average current represents power consumption of the integrated circuit.
In yet another embodiment of the present invention, a power consumption measurement module for an integrated circuit is provided. The integrated circuit includes a plurality of electronic components, and a voltage regulator controller that receives an input supply voltage from an input power supply, and generates a control voltage. A voltage driver has a gate terminal connected to an output of the voltage regulator controller for receiving the control voltage, a source terminal connected to the input power supply for receiving the input supply voltage, and a drain terminal connected to the plurality of electronic components for providing a regulated voltage thereto. The power consumption measurement module includes a unity gain buffer, connected to the gate terminal of the voltage driver, for receiving and buffering the control voltage. An analog-to-digital converter (ADC) is connected to the unity gain buffer for receiving and sampling the control voltage to generate a plurality of digital control voltage samples. An averaging module is connected to the ADC for receiving and averaging the plurality of digital control voltage samples, to generate an averaged control voltage data. A control register is connected to the averaging module for receiving and storing the averaged control voltage data. A current profiling module is connected to the control register for receiving the averaged control voltage data, and determining an average current, wherein the average current represents power consumption of the integrated circuit.
Various embodiments of the present invention provide a system for measuring power consumption of an integrated circuit. The integrated circuit includes a plurality of electronic components, a voltage regulator for generating a control voltage, and a power consumption measurement module connected to the voltage regulator. The power consumption measurement module includes an analog-to-digital converter (ADC) for receiving and converting the control voltage to a plurality of digital control voltage samples, an averaging module for averaging the plurality of digital control voltage samples to generate an averaged control voltage data, and a current profiling module for generating an average current from the averaged control voltage data. The average current represents power consumption of the integrated circuit and may be used to diagnose effect of one or more instructions of an application software program that runs on the electronic components, on the power consumption of the integrated circuit. The average current may further be used to optimize the application software program during execution to minimize the power consumption. The average current may also be used to generate a low voltage detect (LVD) signal when the average current increases beyond a first predetermined threshold current, without using external low voltage detectors and external current probes, which reduces overall costs of the IC operation.
Referring now to
The voltage driver 110 may be a p-type metal oxide semiconductor (PMOS) driver that has a gate terminal connected to an output of the voltage regulator controller 108 for receiving the control voltage Vgs, a source terminal connected to the input power supply for receiving the input supply voltage Vdd, and a drain terminal connected to the electronic components 104 for providing the regulated voltage Vreg. The voltage driver 110 operates in a saturation mode to provide a drain current Idd to the electronic components 104 based on the control voltage Vgs. At constant regulated voltage Vreg, the drain current Idd is proportional to the control voltage Vgs and the relationship between the drain current Idd and the control voltage Vgs in saturation mode operation of the voltage driver 110 is given by the equation below:
Idd=k(Vgs−Vt)2 (1)
The power consumption measurement module 102 is connected to the voltage regulator 106 (i.e., to the gate terminal of the voltage driver 110) and includes a unity gain buffer 112, an analog-to-digital converter (ADC) 114, an averaging module 116, a control register 118, and a current profiling module 120.
The unity gain buffer 112 has a first input terminal connected to the gate terminal of the voltage driver 110 and a second input terminal connected to an output terminal thereof. The unity gain buffer 112 receives and buffers the control voltage Vgs. The ADC 114 is connected to the output terminal of the unity gain buffer 112 and receives and samples the control voltage Vgs. The sampling rate of the ADC 114 may be pre-programmed to generate a plurality of digital control voltage samples.
The averaging module 116 is connected to the ADC 114 and receives and averages the digital control voltage samples and generates an averaged control voltage data. In an embodiment of the present invention, the function of the averaging module 116 may be programmed in to an ASIC by way of software instructions. The control register 118 is connected to the averaging module 116 and receives and stores the averaged control voltage data. In an exemplary embodiment of the present invention, the control register 118 is a first-in first-out (FIFO) register.
The current profiling module 120 is connected to the control register 118 and receives the averaged control voltage data and generates an average current Iavg. In an embodiment of the present invention, the function of the current profiling module 120 may be programmed in to an ASIC using software instructions. The average current Iavg is approximately equal to the drain current Idd and is estimated by the equation below:
I
avg=β(Vgs+γ(Vdd−3)−Vt−δ(T+40))α (2)
The equation (2) is obtained by adding correction factors for Vdd and temperature to the equation (1) for accounting Vdd and temperature variations and minimizing a mean squared error between the average current Iavg and the drain current Idd.
The IC 100 may further include an internal low voltage detection module 122 that is connected to the current profiling module 120 and generates a low voltage detect (LVD) signal when the average current Iavg increases beyond a first predetermined threshold current. The IC 100 may then transition into a reset or interrupt or safe state based on the LVD signal.
In an embodiment of the present invention, an external diagnostic module 124 may be connected to the control register 118 by way of a general purpose input/output (GPIO) interface (not shown) and generates the current profile 200 based on the averaged control voltage data and analyses the power consumption of the IC 100, with respect to one or more instructions of an application software program executed on the IC 100. The diagnostic module 124 accesses the averaged control voltage data from the GPIO interface by way of direct memory access (DMA). The diagnostic module 124 may be a software program that determines the average current Iavg based on the averaged control voltage data using the equation (2) and diagnoses effect of one or more instructions of the application software over power consumption of the IC 100.
In various embodiments, the diagnostic module 124 may be connected to an oscilloscope 126 (external to the IC 100) that displays the current profile 200.
In another embodiment of the present invention, the diagnostic module 124 may be used to optimize an application software program during development of the software program, based on the average current Iavg of the IC 100. The diagnostic module 124 identifies and modifies instructions of the application software program that cause excessive power consumption during execution. The diagnostic module 124 may set a threshold power consumption for the application software program, and include a safe state mechanism in the application software program in case the IC 100 exceeds the threshold power consumption during execution of the application software program.
While particular embodiments of the present invention have been shown and described, it will be recognized to those skilled in the art that, based upon the teachings herein, further changes and modifications may be made without departing from this invention and its broader aspects, and thus, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this invention.
