Analog front end circuit for converting analog signal outputted by image sensor into digital signal
First Claim
1. An analog front end circuit converting an analog signal outputted by an image sensor into a digital signal, the analog signal comprising a first voltage level signal and a first reference signal, the analog front end circuit comprising:
- a sample and hold circuit comprising;
a variable gain amplifier circuit comprising a first input end, a second input end, and at least one output end, the first input end being used for receiving the first voltage level signal, the second input end being used for receiving the first reference signal, the output end being used for outputting at least an amplified signal,a first sample switch in the front end of the first input end,a second sample switch in the front end of the second input end, anda hold switch connected between the first input end and the second input end,wherein the first sample switch and the second sample switch are both controlled by a sample pulse signal,wherein while the first sample switch is at a first conductive state, the first input end receives the first voltage level signal, while the second sample switch is at the first conductive state, the second input end receives the first reference signal, and while the hold switch is at a second conductive state, the output end outputs the amplified signal; and
an analog to digital converter device for receiving the amplified signal and converting the amplified signal into the digital signal.
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Accused Products
Abstract
An analog front end circuit comprises a variable gain amplifier circuit (VGA circuit), a first sample switch, a second sample switch, a hold switch and an analog to digital converter device. The VGA circuit comprises a first input end, a second input end, and at least one output end. The first input end is used for receiving first voltage level signals. The second input end is used for receiving first reference signals. The output end is used for outputting at least one amplified signal. While the first sample switch is at a first conductive state, the first input end receives the first voltage level signal. While the second sample switch is at the first conductive state, the second input end receives the first reference signal. Finally, while the hold switch is at a second conductive state, the output end outputs the amplified signal.
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Citations
20 Claims
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1. An analog front end circuit converting an analog signal outputted by an image sensor into a digital signal, the analog signal comprising a first voltage level signal and a first reference signal, the analog front end circuit comprising:
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a sample and hold circuit comprising; a variable gain amplifier circuit comprising a first input end, a second input end, and at least one output end, the first input end being used for receiving the first voltage level signal, the second input end being used for receiving the first reference signal, the output end being used for outputting at least an amplified signal, a first sample switch in the front end of the first input end, a second sample switch in the front end of the second input end, and a hold switch connected between the first input end and the second input end, wherein the first sample switch and the second sample switch are both controlled by a sample pulse signal, wherein while the first sample switch is at a first conductive state, the first input end receives the first voltage level signal, while the second sample switch is at the first conductive state, the second input end receives the first reference signal, and while the hold switch is at a second conductive state, the output end outputs the amplified signal; and an analog to digital converter device for receiving the amplified signal and converting the amplified signal into the digital signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An analog front end signal process method converting an analog signal outputted by an image sensor to a digital signal, the analog signal comprising a first voltage level signal and a first reference signal, the method comprising the following steps:
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(a) receiving the first voltage level signal by a first input end of a variable gain amplifier circuit when a first sample switch in the front end of the first input end is set at a first conductive state; (b) receiving the first reference signal by a second input end of the variable gain amplifier circuit when a second sample switch in the front end of the second input end is set at the first conductive state; (c) outputting at least one amplified signal via an output end of the variable gain amplifier circuit when a hold switch connected between the first input end and the second input end is at a second conductive state; and (d) converting the amplified signal into the digital signals, wherein the first sample switch and the second sample switch are both controlled by a sample pulse signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification