Interface circuit
First Claim
1. An interface circuit configured to receive a first voltage and a second voltage and generate an interface output signal based on an input signal, the interface circuit comprising:
- a first semiconductor logic gate which receives said first voltage and outputs a first output signal of low level when a signal level of said input signal is not less than a logic threshold value, alternatively outputs said first output signal of high level in response to said first voltage when a signal level of said input signal is less than said logic threshold value;
a second semiconductor logic gate which receives said second voltage and outputs a second output signal of low level when a signal level of said input signal is not less than a logic threshold value, alternatively outputs said second output signal of high level in response to said second voltage when a signal level of said input signal is less than said logic threshold value;
a third semiconductor logic gate which receives said second voltage and outputs a third output signal of low level when a signal level of said first output signal is not less than a logic threshold value, alternatively outputs said third output signal of high level in response to said second voltage when a signal level of said first output signal is less than said logic threshold value; and
a latch circuit which receives said second output signal and said third output signal and generates a 4th output signal and a 5th output signal to output said 4th output signal or said 5th output signal as said interface output signal, whereinsaid latch circuit generates said 4th output signal having an inversed signal level from said second output signal and said 5th output signal having an inversed signal level from said third output signal in a first state in which one of said second output signal and said third output signal is a low level,when, after said first state, both said second output signal and said third output signal transit to a second state of high level, said latch circuit generates said 4th output signal and said 5th output signal holding the respective signal levels of said first state just before transition to said second state.
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Abstract
An interface circuit includes at least one semiconductor logic gate and a latch circuit. The semiconductor logic gate configured to receive an input signal having a signal level changeable and outputs a logic gate signal which has a signal level becoming a low level when a signal level of the input signal is not less than a logic threshold value, alternatively has a signal level becoming a high level when a signal level of the input signal is less than the logic threshold value. The latch circuit fetches the logic gate signal as a first latch signal, while fetching a signal which is converted from the input signal and has a signal level varying between a second voltage and the ground potential, alternatively, the input signal as a second latch signal, to output the first interface output signal and the second interface output signal.
40 Citations
16 Claims
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1. An interface circuit configured to receive a first voltage and a second voltage and generate an interface output signal based on an input signal, the interface circuit comprising:
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a first semiconductor logic gate which receives said first voltage and outputs a first output signal of low level when a signal level of said input signal is not less than a logic threshold value, alternatively outputs said first output signal of high level in response to said first voltage when a signal level of said input signal is less than said logic threshold value; a second semiconductor logic gate which receives said second voltage and outputs a second output signal of low level when a signal level of said input signal is not less than a logic threshold value, alternatively outputs said second output signal of high level in response to said second voltage when a signal level of said input signal is less than said logic threshold value; a third semiconductor logic gate which receives said second voltage and outputs a third output signal of low level when a signal level of said first output signal is not less than a logic threshold value, alternatively outputs said third output signal of high level in response to said second voltage when a signal level of said first output signal is less than said logic threshold value; and a latch circuit which receives said second output signal and said third output signal and generates a 4th output signal and a 5th output signal to output said 4th output signal or said 5th output signal as said interface output signal, wherein said latch circuit generates said 4th output signal having an inversed signal level from said second output signal and said 5th output signal having an inversed signal level from said third output signal in a first state in which one of said second output signal and said third output signal is a low level, when, after said first state, both said second output signal and said third output signal transit to a second state of high level, said latch circuit generates said 4th output signal and said 5th output signal holding the respective signal levels of said first state just before transition to said second state. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An interface circuit configured to receive a first voltage and a second voltage and generate an interface output signal based on an input signal, the interface circuit comprising:
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a first semiconductor logic gate which receives said first voltage and outputs a first output signal in response to said input signal; a second semiconductor logic gate which receives said second voltage and outputs a second output signal in response to said input signal; a third semiconductor logic gate which receives said second voltage and outputs a third output signal in response to said first output signal; and a latch circuit which receives said second output signal and said third output signal being input and generates said interface output signal, wherein said latch circuit outputs an output value, as said interface output signal, reflecting said second output signal and said third output signal when said second output signal and said third output signal being input have logic values different from each other, when both logic values of said second output signal and said third output signal being input are the same, said latch circuit maintains said output value just before both the logic values become the same and outputs said output value as said interface output signal.
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9. An interface circuit configured to receive a first voltage and a second voltage and generate an interface output signal based on an input signal, the interface circuit comprising:
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a semiconductor logic gate configured to receive the input signal having a signal level changeable between the first voltage and a ground potential and to output a logic gate signal which has a signal level becoming a low level when a signal level of said input signal is not less than a logic threshold value, and, alternatively has a signal level becoming a high level when a signal level of said input signal is less than said logic threshold value; and a latch circuit which fetches said logic gate signal as a first latch signal, while fetching a signal which is converted from said input signal and has a signal level varying between the second voltage and the ground potential, and which fetches, alternatively, said input signal as a second latch signal, to output the first interface output signal and the second interface output signal, wherein said latch circuit outputs a signal having an inversed signal level from the signal level of said first latch signal as said first interface output signal and outputs a signal having an inversed signal level from the signal level of said second latch signal as said second interface output signal in a first state in which only one of said first latch signal and second latch signal is a low level, and when both said first latch signal and said second latch signal transit from said first state to a second state in which both said first latch signal and said second latch signal are in a high level or in a low level, said latch circuit outputs at least one of said first interface output signal and said second interface output signal holding the respective signal levels of said first state just before transition from said second state to said second state. - View Dependent Claims (10, 11, 12, 13, 14)
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15. An interface circuit configured to receive a first voltage and a second voltage and generate an interface output signal based on an input signal, the interface circuit comprising:
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a latch circuit to which the input signal and said first voltage are supplied, the input signal having a signal level changeable between the first voltage and a ground potential, to output the output signal, wherein said latch circuit outputs said output signal as a signal having a signal level varying with an opposite phase to said input signal in a first state in which the voltage level of said first voltage is higher than the logic threshold value, and when the voltage level of said first voltage transit from said first state to a second state in which the voltage level of said first voltage is less than said logic threshold value, said latch circuit outputs holding the signal level in said first state just before transition to said second state. - View Dependent Claims (16)
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Specification