Monolithic overvoltage protection device
First Claim
1. A protection device against overvoltages liable to occur between two supply terminals (A, B) comprising, between said terminals, an avalanche triggered thyristor (6) having a determined break-over voltage (VBO) further comprising a zener diode (4) in parallel and reversely connected with said thyristor, said diode being selected so that its avalanche voltage (VBR) is lower than said break-over voltage and gets higher only for overvoltages having a duration of amplitude longer than a predetermined threshold.
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Abstract
A protection device against overvoltages liable to occur between two supply terminals (A, B) comprises between the supply terminals, an avalanche triggered thyristor (6) having a determined break-over voltage (VBO) This system further comprises a zener diode (4) in parallel and reversely connected with the thyristor; the diode is selected so that its avalanche voltage (VBR) is lower than the break-over voltage of the thyristor and gets higher only for overvoltages having a higher duration or amplitude than a predetermined threshold.
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Citations
15 Claims
- 1. A protection device against overvoltages liable to occur between two supply terminals (A, B) comprising, between said terminals, an avalanche triggered thyristor (6) having a determined break-over voltage (VBO) further comprising a zener diode (4) in parallel and reversely connected with said thyristor, said diode being selected so that its avalanche voltage (VBR) is lower than said break-over voltage and gets higher only for overvoltages having a duration of amplitude longer than a predetermined threshold.
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5. An overvoltage protection device comprising:
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a gateless avalanche triggered thyristor having a cathode and an anode and having a predetermined break-over voltage; and a zener diode connected in parallel with said thyristor, an anode of said zener diode connected to said cathode of said thyristor and a cathode of said zener diode connected to said anode of said thyristor, said zener diode having an avalanche voltage that is lower than said break-over voltage of said thyristor, said avalanche voltage increasing in response to overvoltages applied to said zener diode having a duration or an amplitude longer than a predetermined threshold. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. The monolithic semiconductor component, comprising:
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an N-type semiconductor substrate having a first P type region formed in an upper major surface thereof; a first vertical portion of said substrate including a first N-type region formed in said first P type region and a second P type region formed in a lower major surface of said substrate in said first vertical portion, said first vertical portion forming a gateless avalanche triggered thyristor; a second vertical portion of said substrate laterally adjacent said first vertical portion including a second N-type region formed in said lower major surface of said substrate in said second vertical region adjacent said second P type region, said second vertical portion forming a zener diode; and first and second metallization layers respectively formed on said upper and lower major surfaces of said substrate respectively connecting (i) an anode of said zener diode to a cathode of said thyristor, and (ii) a cathode of said zener diode to an anode of said thyristor, an NP junction formed between said substrate and said first P-type region having a higher concentration gradient in said second vertical portion than in said first vertical portion. - View Dependent Claims (14, 15)
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Specification