# US 5,347,418 A · Fuse blowout detector circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,347,418 A - Document ID: US5347418A - Status: Granted - Kind: A - Application number: 07/842,658 - Filed: 1992-02-27 - Granted: 1994-09-13 - Earliest claimed: 1991-02-27 - Assignees: Mitsubishi Denki Kabushiki Kaisha - Inventors: Takahiko Ando; Toshihito Mizoe - Web page: https://patentgrep.com/patent/US5347418A ## CPC - H02H 3/046: {Signalling the blowing of a fuse (detecting non functioning of a lamp H05B47/20)} - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) ## Abstract A fuse blowout detector circuit wherein the primary side of an insulated signal coupler, such as a photocoupler, is connected in parallel with a series circuit connection of a power supply and a fuse, whereby a fuse blowout detection signal is output from the secondary side of the signal coupler, independently of the ON/OFF state of the switch, when the fuse is blown. ## Claims ### Claim 1 A fuse blowout detector circuit for insertion between a power supply and a load device of an electrical circuit which includes a switching means for controlling the supply of power from said power supply to said load, said fuse blowout detector circuit comprising: fuse means for protecting said load device from an overcurrent; an output circuit for outputting a fuse blowout detection signal; and insulated switching means having a primary side and a secondary side, said primary side being connected in parallel with a series connection of said power supply and said fuse means, said secondary side being connected to said output circuit for initiating output of a fuse blowout detection signal from said output circuit when said fuse means is blown, independently of an on/off state of said switching means. ### Claim 2 (depends on 1) The fuse blowout detector circuit of claim 1, wherein said insulated switching means comprises a photocoupler means. ### Claim 3 (depends on 1) The fuse blowout detector circuit of claim 1, wherein said insulated switching means comprises a phototransistor. ### Claim 4 (depends on 1) The fuse blowout detector circuit of claim 1, wherein a protective resistance means is connected between said insulated switching means and said fuse means. ### Claim 5 A fuse blowout detector circuit for insertion between a power supply and a load device of an electrical circuit which includes a switching means for controlling the supply of power from said power supply to said load, said fuse blowout detector circuit comprising: fuse means for protecting said load device from an overcurrent; an output circuit for outputting a fuse blowout detection signal; insulated switching means having a primary side and a secondary side; and an independent power supply means connected to a junction point between said fuse means and said power supply and to said primary side of said insulating switching means to supply power to the primary side of said insulated switching means; said primary side of said insulated switching means being connected in parallel with said fuse means, said secondary side being connected to said output circuit for initiating output of a fuse blowout detection signal from said output circuit when said fuse means is blown, independently of an on/off state of said switching means. ### Claim 6 (depends on 5) The fuse blowout detector circuit of claim 5, wherein a protective resistance means is connected between said insulated switching means and said fuse means. ### Claim 7 A fuse blowout detector circuit for insertion between a power supply and a load device of an electrical circuit which includes a switching means for controlling the supply of power from said power supply to said load, said fuse blowout detector circuit comprising: fuse means for protecting said load device from an overcurrent; an output circuit for outputting a fuse blowout detection signal; and insulated switching means, wherein said insulated switching means is connected in parallel with said fuse means and wherein a second power source is connected in series with said insulated switching means. ### Claim 8 (depends on 7) The fuse blowout detector circuit of claim 7, wherein a protective resistance means is connected between said insulated switching means and said fuse means. ### Claim 9 A fuse blowout detector circuit for insertion between a power supply and a load device of an electrical circuit including switching means for controlling the supply of power from said power supply to said load device and a fuse for protecting said load device from an overcurrent, said fuse blowout detector circuit comprising: a first insulated signal coupler means having a primary side connected in parallel with both ends of a circuit comprising a series connection of said power supply and said fuse, and a secondary side insulated from said first side for outputting a fuse blowout detection signal when said fuse is blown, independently of an on/off state of said switching means, and a second insulated signal coupler means having a primary side thereof connected in parallel with both ends of said power supply and a secondary side for outputting a power off detection signal when said power supply is switched off. ### Claim 10 (depends on 9) The fuse blowout circuit of claim 9, wherein at least one of said first and second insulated signal coupler means comprises an electronic switching means. ### Claim 11 (depends on 10) The fuse blowout circuit of claim 10, wherein a protective resistor is connected between said electronic switching means and said fuse. ### Claim 12 (depends on 10) The fuse blowout circuit of claim 10, wherein said electronic switching means comprises a photocoupler comprising a light-emitting diode and a phototransistor. ### Claim 13 (depends on 9) The fuse blowout circuit of claim 9, wherein at least one of said first and second insulated signal coupler means comprises a relay means.