Power supply unit
First Claim
1. A power supply unit which switches a DC signal to produce an AC signal, and supplies a power supply output based on the produced AC signal, comprising:
- a monitoring circuit for monitoring a previously set upper and lower limit threshold values to provide a threshold value range for said power supply output, and generating a normal verification signal indicating a normal condition when said power supply output is within said threshold value range;
a first switching element for passing or interrupting said DC signal for input to a primary side of a transformner;
a switching control circuit for generating a control signal for ON/OFF switching of said first switching element, which generates the power supply output based on the AC power supply output generated in a secondary side of said transformer with ON/OFF operation of said first switching element, and at the same time inputs said power supply output to said switching control circuit and compares the power supply output with a target level set within said threshold value range, and controls said control signal so that a level of the power supply output approaches said target level, to stabilize the power supply output; and
a start circuit for generating a start signal for starting power supply output, wherein said power supply output is supplied to outside of said power supply unit when the normal verification signal is generated from said monitoring circuit, and when at least one of said start signal and said normal verification signal is being generated, the control signal of said switching control circuit is supplied to the first switching element.
1 Assignment
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Accused Products
Abstract
The invention relates to a power supply unit which can fail-safely monitor not only for an excessive power supply output but also for an abnormal drop in output level. At the time of start-up, with the start signal from a start circuit, an AC signal is supplied to a primary side of a transformer and based on an AC output from a secondary side of the transformer, an output for supplying to an external load is generated and this output is monitored with a monitoring circuit. If the output level is within a set upper and lower limit threshold value range the output is judged to be normal and a high level normal verification signal is generated from the monitoring circuit, and with the high level normal verification signal, an AC signal is supplied to the primary side of the transformer, and the output supply to the external load is continued.
45 Citations
44 Claims
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1. A power supply unit which switches a DC signal to produce an AC signal, and supplies a power supply output based on the produced AC signal, comprising:
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a monitoring circuit for monitoring a previously set upper and lower limit threshold values to provide a threshold value range for said power supply output, and generating a normal verification signal indicating a normal condition when said power supply output is within said threshold value range;
a first switching element for passing or interrupting said DC signal for input to a primary side of a transformner;
a switching control circuit for generating a control signal for ON/OFF switching of said first switching element, which generates the power supply output based on the AC power supply output generated in a secondary side of said transformer with ON/OFF operation of said first switching element, and at the same time inputs said power supply output to said switching control circuit and compares the power supply output with a target level set within said threshold value range, and controls said control signal so that a level of the power supply output approaches said target level, to stabilize the power supply output; and
a start circuit for generating a start signal for starting power supply output, wherein said power supply output is supplied to outside of said power supply unit when the normal verification signal is generated from said monitoring circuit, and when at least one of said start signal and said normal verification signal is being generated, the control signal of said switching control circuit is supplied to the first switching element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A power supply unit which switches a DC signal to produce an AC signal, and supplies a power supply output based on the produced AC signal, comprising;
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a monitoring circuit for monitoring a previously set upper and lower limit threshold values to provide a threshold value range for said power supply output, and generating a normal verification signal indicating a normal condition when the produced AC signal is within said threshold value range;
a first switching element for passing or interrupting said DC signal for input to a primary side of a transformer; and
a switching control circuit for generating a control signal for ON/OFF switching of said first switching element, which generates the power supply output based on the AC power supply output generated in a secondary side of said transformer with ON/OFF operation of said first switching element and supplies the power supply output to outside of said power supply unit, and at the same time inputs said power supply output to said switching control circuit and compares this with a target level set within said threshold value range, and controls said control signal so that a level of the power supply output approaches said target level, to stabilize the power supply output, wherein said power supply output is supplied to outside of said power supply unit when the normal verification signal is generated from said monitoring circuit, and a switch means is provided in an output supply path for supplying said power supply output, and said switch means is driven by the normal verification signal of said monitoring circuit to thereby conduct the output supply path. - View Dependent Claims (38, 39, 40)
said monitoring circuit drives said second switch based on the output from said second off-delay means and drives said first switch based on the output from said on-delay means.
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41. A power supply unit which switches a DC signal to produce an AC signal, and supplies a power supply output based on the produced AC signal, comprising:
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a monitoring circuit for monitoring a previously set upper and lower limit threshold values to provide a threshold value range for said power supply output, and generating a normal verification signal indicating a normal condition when said produced AC signal is within said threshold value range, wherein said power supply output is supplied to outside of said power supply unit when the normal verification signal is generated from said monitoring circuit, with an AC power supply unit incorporating an oscillator for generating an oscillating signal with input of said DC signal, and an output circuit having a switch circuit which is switchingly operated with the oscillation signal from said oscillator to generate an AC power supply output, supply of the AC power supply output to outside of said power supply unit is made possible when the normal verification signal is being generated from said monitoring circuit, the construction is such that when said normal verification signal is being generated, said oscillating signal from said oscillator is transmitted to said switch circuit, and a band-pass filter with a previously set predetermined frequency for the oscillator signal as a central frequency, is disposed in a signal supply path for supplying the oscillating signal from said oscillator to the switch circuit.
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42. A power supply unit which switches a DC signal to produce an AC signal, and supplies a power supply output based on the produced AC signal, comprising:
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a monitoring circuit for monitoring a previously set upper and lower limit threshold values to provide a threshold value range for said power supply output, and generating a normal verification signal indicating a normal condition when the produced AC signal is within said threshold value range, wherein said power supply output is supplied to outside of said power supply unit when the normal verification signal is generated from said monitoring circuit, with an AC power supply unit incorporating an oscillator for generating an oscillating signal with input of said DC signal, and an output circuit having a switch circuit which is switchingly operated with the oscillation signal from said oscillator to generate an AC power supply output, supply of the AC power supply output to outside of said power supply unit is made possible when the normal verification signal is being generated from said monitoring circuit, a switch means is disposed in an output supply path for supplying said power supply output, and said switch means is driven by the generation of the normal verification signal from said monitoring circuit to conduct the output supply path and supply the power supply output, there is provided a switch off verification circuit for detecting an OFF condition of said switch means and outputting an off verification signal, and said monitoring circuit is able to generate the normal verification signal on the condition that said off verification signal is being generated, said monitoring circuit incorporates a level verification means for verifying that a voltage level of the power output is within said threshold value range, a frequency verification means for verifying that the power supply output frequency is within a predetermined frequency range based on a pulse width of the power supply output, a logical product means into which the outputs of the two verification means are connected and a self hold means with an output from said logical product means connected to a hold input terminal, and the off verification signal from said switch off verification circuit connected to a trigger input terminal, and said self hold means holds the trigger input by its own input, and said switch means is driven based on the output from said self hold means. - View Dependent Claims (43)
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44. A power supply unit which switches a DC signal to produce an AC signal, and supplies a power supply output based on the produced AC signal, comprising:
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a monitoring circuit for monitoring a previously set upper and lower limit threshold values to provide a threshold value range for said power supply output, and generating a normal verification signal indicating a normal condition when the produced AC signal is within said threshold value range, wherein said power supply output is supplied to outside of said power supply unit when the normal verification signal is generated from said monitoring circuit, with an AC power supply unit incorporating an oscillator for generating an oscillating signal with input of said DC signal, and an output circuit having a switch circuit which is switchingly operated with the oscillation signal from said oscillator to generate an AC power supply output, supply of the AC power supply output to outside of said power supply unit is made possible when the normal verification signal is being generated from said monitoring circuit, a switch means is disposed in an output supply path for supplying said power supply output, and said switch means is driven by the generation of the normal verification signal from said monitoring circuit to conduct the output supply path and supply the power supply output, said switch means has two switches connected in series, and said monitoring circuit generates the normal verification signal on the condition that one switch is off, and there is provided a switch drive means for intermittently switching the other switch off based on said normal verification signal, and a switch performance verification means for detecting ON/OFF switching of said other switch and generating a hold signal so that the normal verification signal continues and inputting the hold signal to said monitoring circuit, and said one switch is driven ON by the normal verification signal of said monitoring circuit.
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Specification