Integrated circuit with self-proofreading function and measuring device using the same

An integrated circuit (IC) includes a micro control unit (MCU), a one-time programmable (OTP) memory directly connected with the MCU, an electrical charge pump having an output port and an enable port connected to the MCU, and a switching circuit having a control port connected to the MCU, a first input port connected to the output port of the electrical charge pump, a second input port connected to a power source of the MCU, and an output port connected to the OTP memory to provide an operating voltage and a recording voltage for the OTP memory. Because the OTP memory can choose the operating voltage or the recording voltage, a measuring apparatus using this IC doesn't need an external power source to provide a VDD voltage being 5.8 volts. Therefore, a power consuming of the IC can be reduced.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an integrated circuit (IC) for measuring and an electrical measuring apparatus using the IC.

2. Description of the Related Art

Currently, a conventional integrated circuit for measuring includes an analog digital converter (ADC), a micro control unit (MCU), a system memory, and so on. Furthermore, the MCU includes a random access memory (RAM), a central processing unit (CPU) and a programmable interface, etc.

When an integrated circuit is utilized in measuring devices, sensors for measuring pressures or weights are receiving measuring signals. The sensors convert the measuring signals to electrical signals, such as voltage signals or current signals. The electrical signals are converted into digital signals by the analog-to-digital converter of the integrated circuit. And then, the digital signals are computed, processed or further converted by the MCU, and are displayed on an external display. The MCU computes, processes or further converts the signals by an instruction set stored in the system memory. The total and order of the instructions construct a program.

However, in the above utilizations, many of the integrated circuits having an analog-to-digital converter must perform a proofreading process before displaying an accurate measuring value. In the proofreading process, a standard measuring object having standard values is used. A sensor communicates with the standard measuring object to send out a standard signal. The standard signal is converted to a digital signal used as a standard value to be stored in the memory. When the MCU performs a normal measuring program, the standard value is taken out to compute an actual measuring value according to a measuring signal. After the proofreading process, a proofreading coefficient is produced correspondingly. The proofreading coefficient must be stored and can be read by the MCU, so that the MCU can accurately perform a computation or a conversion to obtain an accurate value. Therefore, most of electrical elements require an electrically erasable programmable read-only memory (EEPROM) to store the proofreading coefficient.

However, an additional burner is needed to write the proofreading accurately in the EEPROM. After the step of writing, the EEPROM is taken out from the burner and is communicated with an electrical measuring device of a terminal system to finish the proofreading process.

At present, there may be some better methods for recording the proofreading parameters, and it's not necessary to take the EEPROM out of terminal system product as described above. Referring toFIG. 1, a conventional IC100is shown. The IC100is connected to a display115, an EEPROM105and a sensor101. Before performing a measuring program, the IC100must perform a proofreading procedure. The proofreading procedure includes the following steps: a first step of directly contacting the sensor101with a standard object (not shown), a second step of outputting a standard analogical signal to an ADC103by the sensor101, a third step of outputting a standard digital signal to an MCU109by the ADC103according to the standard analogical signal, and a fourth step of storing standard parameters into an EEPROM105through a serial interface circuit107after processed by MCU109. When the MCU109performs any instruction, the MCU109must access instruction sets from an erasable programmable read-only memory (EPROM)111.

After finishing the proofreading procedure, the standard parameters are stored into the EEPROM105. When a normal measuring procedure is performed, the sensor101directly contacts with an object to be measured and outputs a measuring signal to the ADC103. After a step of transforming, the ADC103outputs a digital measuring signal to the MCU109, and the MCU109reads the standard parameters form the EEPROM105through the serial interface circuit107. After a step of computing, the MCU109outputs a measuring result to the display115through a timing-controller113. The MCU109must compute the measuring result according to the standard parameters stored in the EEPROM105. The MCU109must use the serial interface circuit107to access the standard parameters. The EEPROM105is externally connected to the IC100.

The above way of storing the standard parameters into an external memory has an advantage that the EEPROM105is easily accessed, but it increases a cost of the whole measuring system. In addition, when the proofreading procedure is performed or the program memory is recorded, terminal system products need two extra voltage source VPP=12 volt and VDD=5.8 volt, except for a normal chip power source.

What is needed is to provide an IC with a simple proofreading procedure, a low cost and having a self-proofreading function.

BRIEF SUMMARY

An integrated circuit (IC) with a self-proofreading function includes a micro control unit (MCU), a one-time programmable (OTP) memory directly connected with the MCU, an electrical charge pump having an output port and an enable port connected to the MCU, and a switching circuit having a control port connected to the MCU; a first input port connected to the output port of the electrical charge pump, a second input port connected to a power source of the MCU, and an output port connected to the OTP memory to provide an operating voltage and a recording voltage for the OTP memory.

The IC further includes an analog digital converter (ADC) connected to the MCU, wherein the ADC is used for receiving measuring signals and converting the measuring signals to digital signals. The IC further includes a timing controller connected to the MCU, wherein the MCU outputs a measuring result by the timing controller.

A measuring apparatus with a self-proofreading function includes a sensor, and a measuring circuit. The measuring circuit includes a micro control unit (MCU) for receiving digital signals, an analog digital converter (ADC) connected to the MCU, and a one-time programmable (OTP) memory connecting with the MCU. The ADC is used for receiving measuring signals from the sensor and converting the measuring signals to digital signals. The measuring circuit further includes an electrical charge pump and a switching circuit. The electrical charge pump has an output port and an enable port connected to the MCU. The switching circuit has a control port connected to the MCU; a first input port connected to the output port of the electrical charge pump, a second input port connected to a power source of the MCU, and an output port connected to the OTP memory to provide an operating voltage and a recording voltage for the OTP memory.

The measuring apparatus further includes a timing controller connected to the MCU, wherein the MCU outputs an actual measuring result by the timing controller. The measuring apparatus further includes a display connected to the timing conroller and used for displaying the actual measuring result.

As the above description, because the electric charge pump is provide in the IC or the measuring circuit, the OTP memory can have the operating voltage and the recording voltage to be chosen. According a working state of the OTP memory, the OTP memory can select a corresponding voltage. Therefore, the measuring apparatus doesn't need an external power source to provide a VDD voltage being 5.8 volts. And thus, the IC can reduce an external power source when standard parameters are recorded, and a power consuming of the IC can be reduced.

When the IC is applied, because the IC can provide the recording voltage and record standard parameters into the OTP memory without an external memory such as EEPROM, the amount of elements of the measuring apparatus is reduced, and the cost of the measuring apparatus is reduced. The manufacturer of the measuring apparatus doesn't need an external memory to record proofreading parameters before produce the terminal product. And the manufacturer of the measuring apparatus doesn't need to proofread different kinds of parameters according to different kinds of applications beforehand. Therefore, a proofreading procedure is simplified, and costs of the measuring apparatus and the IC can be reduced.

As the above-described, the parameter memory region of the OTP memory can be divided to many sub-divisions, each of which can be used for recording a standard parameter for proofreading at one time. Therefore, the OTP memory of the IC can record proofreading parameters at many times. The IC is more flexibly applied.

DETAILED DESCRIPTION

Reference will now be made to the drawings to describe embodiments of the present invention, in detail.

FIG. 2illustrates a schematic block diagram of a measuring apparatus with a one-time programmable (OTP) memory in accordance with a first embodiment of the present invention. The measuring apparatus includes an integrated circuit (IC)200, a sensor201and a display215. The sensor201outputs a measuring signal to the IC200. The IC200outputs a measuring result of an object to be measured to the display215. In a proofreading procedure, the sensor201contacts with a standard object and outputs a standard signal to an analog digital converter (ADC)203of the IC200. The standard signal is analogical signal and is converted to a digital signal by the ADC203. A micro control unit (MCU)209processes the digital signal to get a standard parameter, which can be stored in a parameter memory region220of an erasable programmable read-only memory (EPROM)211.

FIG. 3is a diagram describing the measuring apparatus in accordance with a second embodiment of the present invention. In this embodiment, the IC200uses an electrical charge pump216to enhance a voltage of the system power and supply an enhanced voltage for recording standard parameters under a proofreading mode. Under the proofreading mode, when proofreading instructions record standard parameters into the parameter memory region220of the OTP memory211, the MCU209outputs an enabling signal to enable the electric charge pump216, and chooses an output voltage of the electric charge pump216by a switching circuit217. The output voltage is provided to the OTP memory211. For example, if the power voltage of the IC200is 3 volts, after being enhanced, the IC200can generate a voltage being 6 volts. Therefore, the terminal system products don't need to connect an external power source with an output voltage being 5.8-volts. That is, the IC200can reduce an external power source when standard parameters are recorded, and thus the power consuming of the IC200is reduced.

According to embodiments of the present invention, the parameter memory region220is a part of the EPROM211. The MCU209can access standard parameters and instructions from the EPROM211directly. When the MCU209executes a computing function, the MCU209can access instructions from the EPROM211to perform.

According to embodiments of the present invention, the EPROM211can be replaced by an OTP memory. Because data stored in the OTP memory needn't to be deleted, it is feasible to replace the EPROM211with the OTP memory.

According to embodiments of the present invention, the sensor201can measure some physical parameters, such as a temperature, a voltage, a water pressure, an electrical current, a liquid flow rate, and so on. The sensor201outputs an analogical measuring signal after measuring the physical parameters.

When the IC200executes a normal measuring procedure, the sensor201directly contacts the object to be measured and outputs a measuring signal to the ADC203. The ADC203converts the measuring signal to a digital measuring signal and outputs the digital measuring signal to the MCU209. The MCU209accesses standard parameters from the parameter memory region220of the EPROM211and computes a measuring result according to the standard parameters. The measuring result is sent to the display215to display via a timing controller213. According to the first embodiment of the invention, the standard parameters for the proofreading procedure are stored in an inside memory region, and thus, the MCU209can access the standard parameters from the EPROM without accessing an outside EPROM. The MCU209can directly access instruction sets210and standard parameters from the EPROM211to execute the proofreading procedure and the measuring procedure, and thus, the serial interface circuit can be cut off and the operating speed of the IC200is enhanced. On the other hand, the standard parameters are stored in the EPROM211, and the MCU209can access the standard parameters from the EPROM211. Therefore, the measuring system using the IC200does not need an external EEPROM, and a cost of the measuring system can be reduced.

FIG. 4is a flowchart of the proofreading procedure and the measuring procedure according to the IC200with the EPROM211, as shown inFIG. 3. In a step301, the IC200starts to work. In a step303, whether or not the IC200is operating under a proofreading mode is judged. If it is, the proofreading procedure jumps to a step305; if it is not, the proofreading procedure jumps to a step331. In the step305, the ADC203provides standard parameters to the MCU209. In a next step307, the MCU209searches storing addresses of the standard parameters in the EPROM211. In a next step309, the MCU209judges whether the storing addresses are void, and whether the standard parameters have been stored in the storing addresses. If the storing addresses are void, the proofreading procedure jumps to a step311. If the standard parameters have been stored in the storing addresses, the proofreading procedure jumps to a step319, and the self-proofreading procedure is ended. In the step311, the MCU209executes programmable instructions to store the standard parameters in the EPROM211. After the step311, the MCU209judges whether the stored standard parameters are right in a step313. In a next step315, whether the stored standard parameters are right is confirmed. If it is, the proofreading procedure jumps to the step319, and the self-proofreading procedure is ended. If it is not, the proofreading procedure jumps to the step317to display an error information. After that, the proofreading procedure jumps to the step319, and the self-proofreading procedure is ended.

When judging whether or not the IC200is operating under a proofreading mode, if it is not, the step311is executed, and the IC200begins to execute the measuring mode. In the step331, the MCU209accesses the standard parameters from the EPROM211. In a next step333, the MCU209receives the digital measuring signal from the ADC203. After the step333, the MCU209computes a measuring result according to the standard parameters in a step335. Finally, The step319is executed, and the measuring mode is ended.

According to the above embodiments of the present invention, when the IC200uses the OTP memory211, the parameter memory region220can be divided into many sub-regions, each of which can be utilized to store standard parameters at one time under a proofreading mode. Therefore, the IC200can record many times in the OTP memory.