Abstract:
A universal power measurement SoC includes an analog signal conditioning circuit, analog-to-digital converter circuit, memory and micro control unit. The analog signal conditioning circuit receives physical signals from a signal sensor and adjusts the polarities and amplitudes of the signals to produce suitable analog signals and gain status. The analog-to-digital converter circuit converts the adjusted analog signals into digital signals. The memory stores the pre-setup parameters of the power measurement. The micro control unit, according to users&#39; choices, processes the converted digital signals with the gain status to produce the output signals of the power measurement.

Description:
This Nonprovisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 092136930 filed in TAIWAN, R.O.C. on Dec. 25, 2003, the entire contents of which are hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to a programmable power measurement chip, and more particularly to universal power measurement chip architecture that external apparatuses can pre-setup required functions. 
   2. Description of the Prior Art 
   Power measurement circuits are applied in various measurement devices and industrial control apparatuses to convert analog power signals (such as voltage, current, . . . ) into digital power signals for further processing. 
   The architecture of the prior art of power measurement devices, such as voltmeters and ammeters, as shown in  FIG. 1 , includes a signal detector  1 , an analog signal conditioner  2 , an analog-to-digital converter  3 , a micro controller  4 , a power supply  5 , a memory  6 , a communication interface  7 , and an LCD interface  8 . 
   The signal detector  1  can convert physical (analog) signals into voltage signals. After the signal conditioner  2  adjusts the voltage signals into proper amplitude, the analog-to-digital converter  3  converts the adjusted analog signals into digital signals. The micro controller  4  processes the digital signals in accordance with the pre-setup programs. The processed power information can be saved in the memory  6 , shown in the external LCD through the LCD interface  8 , or directed to an external storage apparatus through the communication interface  7 . The power supply  5  is a battery for a handhold meter, or a linear or switching power supply for built-in meter to supply the needed power for each circuit. 
   The mentioned prior art of the circuitry architecture is applied in a voltmeter, then the signal detector  1 , analog signal conditioner  2 , analog-to-digital converter  3 , and programs in the micro controller  4  have to be designed for the characteristics of the voltage measurement. If the architecture is applied in the other power measurements, all the above circuitry and programs have to be redesigned. It lacks flexibility in application. Once the architecture is applied in a universal integrated power measurement apparatus, all of the desired signal detector  1 , analog signal conditioner  2 , and analog-to digital converter  3  have to be incorporated in a single system. Besides, if the micro controller  4  is designed to execute a variety of the power measurement programs, it is necessary to have a processing procedure to arrange the various programs properly to avoid the conflict of the execution. Consequently, the volume of the measurement apparatus is getting much bigger, and the hardware is getting more complicated to increase the chances of the interferences among the programs. Therefore, the prior art of the circuitry architecture is always a big burden for designers and manufacturers, because they have to design and manufacture the meters for each different use according to the need of the market, in no way to respond to the real-time requirement. 
   SUMMARY OF THE INVENTION 
   Obviously, the prior art can not satisfied the design and manufacturing. Accordingly, flexible system chip architecture with optional execution functions as a core of a power measurement apparatus is provided. Users use this chip architecture as the system core of their power measurement apparatus, and then they can select the required measurement functions by the power parameters, values, or input/output setup table of flags from external apparatuses. Or they can input new functions to the chip by the setup procedure of the power operating functions, also re-setup the built-in parameters by transferring data through the communication interface. 
   A further object of the present invention is the provision of a programmable power measurement chip to integrated all the elements in a single chip to reduce the volume. To satisfied the requirements of the IEC 60687, IEC 60256 and ANSI C12.20, the present invention can decrease the number of the necessary components, improve the system stability, reduce the calibration procedure of precision, simplify the manufacturing process, cut down the cost, and increase the flexibility of application. 
   A universal power measurement chip, a system-on-chip (SoC), with programmable execution functions including an analog signal conditioning circuit, analog-to-digital converter, memory and micro controller is provided. The analog signal conditioning circuit can receive an input signal and adjust the signal to generate an adjusted signal with proper amplitude or polarity and a gain status signal. The analog-to-digital converter converts the adjusted signal into digital signal. The memory is used to save the certain pre-setup power parameters. The micro controller processes the converted digital signal to obtain a power measurement output signal according to the measurement items selected by a user, one of the items of the power parameters and the gain status signal. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the invention as well as other objects and features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawings, wherein: 
       FIG. 1  is a diagram of the basic architecture of the prior art of voltmeters, ammeters, . . . etc.; 
       FIG. 2  is a diagram of the architecture of a universal power measurement chip with programmable execution functions; 
       FIG. 3  further shows the configuration of the memory in  FIG. 2 ; and 
       FIG. 4 , as shown in the three views of  FIGS. 4A ,  4 B, and  4 C, is the flowchart of the selection, setup and execution of the functions of the present invention. 
       FIG. 5  is a setup table about the input/output of power parameters, values, and flags in an embodiment. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the  FIG. 2 , it is a diagram of an SoC embodiment of the present invention to illustrate the architecture of a universal power measurement chip. A universal power measurement chip  9  includes an analog signal conditioning unit  10 , an analog-to-digital converting unit  11 , a micro controller unit  12  and a memory unit  15 . A universal power measurement apparatus with programmable execution functions can be set up by means of the universal power measurement chip  9  working with an external signal detector, power supply, LCD, communication peripheral circuit and setup keys. 
   Optionally, the universal power measurement chip  9  further includes a power and voltage reference unit  13 , timing unit  14 , temperature sensor  16 , communication interface unit  17 , LCD driver  18 , and power monitor unit  19 . The power and voltage reference unit  13  receives and stabilizes an external power to provide the stable power for the operation of the universal power measurement chip  9  and reference voltage source for the analog signal conditioning unit  10  and analog-to-digital converting unit  11 . In one embodiment, the power and voltage reference unit  13  includes a power stabilizer and a voltage reference input/output circuit. And the timing unit  14  includes a real-time clock circuit, a watchdog timer circuit, and a timing generation circuit to provide the timing for the operation of every part of the universal power measurement chip  9 . 
   The temperature sensor  16  works with the memory  15  to set up and pass the temperature compensated point to the micro controller unit  12  as the basis of the compensation for the power parameter calculation of the micro controller unit  12 . The temperature sensor  16  also provides the real-time temperature value and passes the value to the memory  15  to save to wait for outputting if needed. Besides, the communication interface unit  17  includes a general-purposed input/output interface, pulse and flag input/output interface, synchronous serial communication interface, asynchronous serial communication interface, and a parallel communication interface to pass the interface data provided by the universal power measurement chip  9  to the external apparatus. 
   The power monitor unit  19  monitors the supply status of the power and pass the data to the micro controller unit  12  to judge. If the supply of the power is abnormal, the measurement is paused, and the measured data is written to the memory  15  to save internally to avoid the data loss because of the power cut. And the LCD driver  18 , controlled by the micro controller unit  12 , displays various power data on the LCD in accordance with the pre-selected data item. 
   In an embodiment of the present invention, the analog signal conditioning unit  10  is responsible for receiving an analog signal to adjust the signal into a voltage/current signal with proper polarity and amplitude, and outputting the adjusted voltage/current signal and a gain control signal. In one embodiment, the analog signal is the physical signal, like voltage, current or pressure, that is received and generated by an external signal detect device. And the signal conditioning unit  10  includes an analog signal conditioning circuit with fixed gain and self-adjusted gain to generate a set of gain control signals. It can make the analog signal become a voltage/current signal with proper polarity and amplitude by means of the amplifying/attenuating the gain control signal to automatically adjust the amplification and attenuation of the input signal. 
   An embodiment of the analog signal conditioning unit  10  refers to the patents of the same applicant as the one of the present invention: ROC Application No. 091221128, filed Dec. 25, 2002, entitled “Analog Signal Section Auto Control Circuit”; ROC novelty Patent No. 188202, filed Dec. 15, 2000, entitled “Automatic Gain Control Circuit For Analog Signals”; U.S. Pat. No. 6,577,191, filed Nov. 8, 2001, entitled “Automatic Gain Control Circuit For Analog Signals”; and China novelty Patent No. ZL01261062-3 filed Sep. 7, 2001, entitled “Automatic Gain Control Circuit For Analog Signals”. 
   The analog-to-digital converting unit  11 , connected with the analog signal conditioning unit  10 , receives the adjusted voltage/current signals, samples and holds the adjusted voltage/current signals to convert into digital signals, and then outputs the digital voltage/current signals. The micro controller unit  12  is used for calculation, judgment, control of display, and control of communication. The micro controller unit  12  also receives the gain status signals coming from the analog signal conditioning unit  10  and the digital signals coming from the analog-to-digital converting unit  11 . And then the pre-selected power parameter calculation function and the output temperature compensation value saved in the memory  15  are read to be processed with the digital signals and the gain status signals for ensuring that the result is accordance with the amplitude of the external signals and the power information is correct. 
   Referring to  FIG. 3 , the embodiment of the memory  15  of the present invention, configured by the character of the information with the required storage addresses and length, includes a data output memory  20 , a data input setup memory  21 , a program storage memory  22 , and a user-defined memory  23 . In this embodiment, the data output memory  20  works as a temporary storage to provide certain options, such as power parameter values, quality of the power harmonic, measuring temperature, and power status. The data input setup memory  21  works as an eternal storage to provide the input options, such as the setup of the threshold value of the Wh-to-Pulse, Creep, Sag, Swell and Power Outage Time, the converting ratio of the Phase Correcting Angle, Wh-to-Pulse, Gain, and sampling rate, the on/off of the HPF, Channel, and BlankROM, the status of CT and the setup of the temperature compensation. 
   The program storage memory  22 , working for storing programs, stores the operation programs and options of the power parameters, the programs and options of the communication protocol, and the display programs and options of the LCD. In this embodiment, the built-in parameter operation program set and options includes communication protocol, data transportation, real-time calculation of the power parameters (Vrms, Irms, Vpeak, Ipeak, W, S, Var, PF, and Line Frequency), parameters for calibration (Gain, DC offset, Phase Correction, FFT, and measuring temperature), and LCD display parameters (power parameters, quality of the power harmonic, temperature, and power status). And the user-defined memory  23  is an empty memory to store programs and data. Users can input the needed programs and data in this area by themselves. 
   The other objects and their architecture designs of the present invention are illustrated in the next embodiment.  FIG. 4 , as shown in the three views of  FIGS. 4A ,  4 B, and  4 C. shows the procedure of the setup and execution of the functions of the chip. After starting, the chip is in the starting micro control unit state (step  30 ), ready for receiving the input from the external apparatus, and also inform the external apparatus that the chip is ready for receiving. After informed, the external apparatus transports a piece of beginning protocol, including the character of the input. The chip determines the character of the input in accordance with the protocol, and then starts receiving. 
   Then the input is judged if it is information (step  32 ). The input will be saved in the data input setup memory  21  (step  33 ), if the input is a power parameter operation execution option code, status flag, compensation setup value, judging limit value, transportation option, or display option. Unless the data input setup memory  21  is re-setup, the data will not be updated. If the input is a newly added function, it will be saved in the program storage memory  22  (step  34 ). Unless the program storage memory  22  is re-setup, the program will not be updated. In the mean time, a new function code will be sent to the data input setup memory  21  to wait for being read by the micro control unit  12  (step  35 ). The external apparatus will send a piece of ending protocol to inform the chip that the transportation is done and the chip will restart (step  37 ) after the external apparatus finishes sending (step  36 ). 
   Once the chip restarts, the micro control unit  12  will restart as well, and drive the analog-to-digital converting unit  11  (step  38 ) to execute the analog-to-digital convert (step  40 ), read the power parameter operation execution option code, status flag, compensation setup value, judging limit value, transportation option, or display option from the data input setup memory  21  (step  39 ), and wait for reading the information, like analog-to-digital converting value and gain status flag. After finishing converting, the analog-to-digital converting unit  11  will immediately write the converting value into the data input setup memory  21  (step  42 ) to wait for being read by the micro control unit  12 . The micro control unit  12  will proceed to operation or judgment in accordance with the power parameter operation execution program, and then save the execution result in the data output memory  21  (step  43 ). The first step result of the operation will be adjusted in accordance with the status flag, judging limit value, and compensation setup value. Then the micro control unit  12  sends the last result to the external storage (step  44 ) or to show on the LCD (step  45 ) by driving the communication interface unit  17  or LCD driver  18  in accordance with the transportation option and display option. By following the procedure, the chip operates continuously until re-setting-up functions. 
     FIG. 5  is a setup table about the input/output of power parameters, values, and flags in an embodiment. With the setup table and the above, the universal power measurement chip architecture with programmable execution functions of the present invention can simplify the design of the firmware and hardware of a power measurement apparatus, and build a low cost apparatus with flexible options to respond to requirements. Therefore, the present invention is very valuable in industry. 
   It is further understood by those skilled in the art that the foregoing description is a preferred embodiment of the disclosed device and that various changes and modifications may be made in the invention without departing from the spirit and scope thereof.