Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1998-11-25
2001-07-10
Hofsass, Jeffery (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S660000, C340S661000, C340S662000, C361S091200
Reexamination Certificate
active
06259371
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Taiwan application serial no. 87112613, filed Jul. 31, 1998, the full disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention generally relates to a power surge detection device, and more particularly to a device for detecting power surges occurring in a computer system.
2. Description of Related Art
A power supply is an essential component in electrical equipment to provide the required power source. Computer systems are no exception. However, the reliability of a power source required by different electrical equipment can be quite different. A computer system typically requires a higher reliability from the power source so as to avoid data loss, calculation errors, or even system failures.
So far, emphasis on a power supply of a computer system is mainly on the following items:
1. The operating efficiency of the power supply:
A switching power supply is generally adopted in a computer system. Therefore, the load factor is maintained at a ratio of about 75%~85% to prevent overloading to the power supply itself.
2. Overload voltage protection:
When the output voltage exceeds the rated voltage by 10%, the power supply is turned off to protect the circuit from being damaged.
3. Overload current protection:
When the output current exceeds the rated current by 10%, the power supply is turned off to protect the circuit from being damaged and prevent further damages due to a short circuit from external circuits.
The power supply currently used in a computer system emphasizes on the above-mentioned protections. Generally, there is no power surge protection built within a computer system.
Power surges occur in many ways from, for example, lightning in the sky, or an operating machine that consumes large power. In the past, the computer can generally tolerate a poorer reliability from the power supply, because the operating speed and frequency are relatively low and the input/output voltages are relatively high. However, the operating speed of computers of the present generation has significantly increased. A central processing unit (CPU) has had an operating frequency up to several hundred MHz. With a pipe line computation, it can execute an instruction per one clock cycle. For example, the Pentium II CPU from INTEL, which adopts a specification of guning transceiver logic (GTL) PLUS bus, has a signal variation ranges from 0~1.5 volt. The threshold voltages for high and low levels are 1.0±200 mV. As a result, the computer system allows only a relatively small range for voltage variation. A power surge to the computer system will significantly affect the input/output signals. Also, since the pipe line of the CPU is well designed, almost an instruction is executed for every clock cycle, which means data are continuously transmitted for every clock cycle. The power surge occurred not only damages the data transmitted from or to the CPU, but also causes data losses, calculation errors, or even system failures.
From the above-mentioned descriptions, it is understood that there is a deficiency in detecting a power surge in a conventional computer system to provide a stable power source required by the computer system that allows only a relatively small range for voltage variation. When a power surge occurs, data losses, calculation errors, or even system failures might occur to the computer system.
SUMMARY OF THE INVENTION
It is therefore an objective of the present invention to provide a power surge detection device to examine if there is any power surge occurring in the power supply to a main processor of a computer system. When the width or frequency of power surges detected jeopardize the normal operation of the computer system, an alerting signal, for example, an interrupt signal or a power management signal, is sent to the main processor to intervene in the normal operation of the computer system so as to avoid the power instability period.
In accordance with the foregoing and other objectives of the present invention, a power surge detection device to detect power surges from a power source is provided, in which a control circuit, a high-speed voltage detection circuit, and a counter are included. The control circuit is responsible for monitoring operations of the power surge detection device. The high-speed voltage detection circuit receives a voltage-controlled signal provided by the control circuit, based on which a detection signal is generated and sent to the counter when a power surge occurs. The counter enumerates the times that power surges have occurred, and sends statistical results to the control circuit.
According to a preferred embodiment of the present invention, the power surge detection device further comprises a main processor interface, which serves as an interface to facilitate the communication between the control circuit and the main processor. The main processor interface can be an integrated circuit bus (I
2
C bus) interface, a system management bus (SMBUS), or an internal register. The power surge detection device further comprises an alerting signal generator coupled to the control circuit. When the counter reaches a preset value, the control circuit issues a command requesting the alerting signal generator to send an alerting signal to the main processor. The alerting signal can be an interrupt signal or a power management signal. The preset value can be set into the control circuit by the main processor via the main processor interface.
The high-speed voltage detection circuit comprises a comparator, a reference voltage generator, and a control gate. The comparator comprises two inputs connected to a reference voltage and a power source, and an output for generating a comparison signal. If the power source has a voltage larger than the reference voltage, the comparison signal from the comparator activates. Different reference voltages can be obtained by controlling the voltage selection control signal. Comparison signal from the comparator between the reference voltage and the power source is connected to a control gate, which outputs a detection signal when the clock is also activated. The control gate can be a AND gate.
The above-mentioned reference voltage generator comprises a voltage generation circuit and a voltage selection circuit. The voltage generation circuit generates a plurality of different output voltages, from which a reference voltage is chosen through the control of the voltage selection circuit. The voltage selection circuit comprises a plurality of switches and a decoder. The inputs of the switch are connected to the voltage outputs from the voltage generation circuit and the outputs of the switches are connected together to provide a reference voltage. The decoder is used to decode the voltage selection control signal into a plurality of switch control signals to control the switches, respectively. Only one switch control signal is activated at one time to turn on a switch.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.
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patent: 5440441 (1995-08-01), Ahuja
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patent: 5959537 (1999-09-01), Banting
patent: 6031705 (2000-02-01), Gscheidle
patent: 6107981 (2000-08-01), Fujita
patent: 6112136 (2000-08-01), Paul
Hofsass Jeffery
Huang Jiawei
J.C. Patents
La Anh
VIA Technologies Inc.
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