| 摘要 |
An intrinsic safety approach is provided for a battery powered communication device. Sparking is prevented at radio contacts during attachment and removal of a battery (104, 204, 304, 404) from a radio (102, 202, 302, 402) through the use of switches (112, 212, 312, 412/424) to isolate the radio capacitors from the radio contacts and/or dissipate energy from the radio capacitor through a discharge resistor (214, 314, 414). |
| 主权项 |
1. A communication device, comprising:
a radio having a radio capacitor and radio contacts, wherein the radio capacitor is coupled across the radio contacts; a battery coupled to the radio via the radio contacts; a first sensing circuit with a predetermined time constant coupled to the radio contacts; a second sensing circuit coupled to the first sensing circuit, wherein the second sensing circuit includes a comparator with a predetermined comparator threshold and an inverter; a first switching circuit coupled to the second sensing circuit, wherein the first switching circuit comprises first switching circuit switches that open in response to removal of the battery from the radio to remove access to the stored energy of the radio capacitor from the radio contacts; wherein the time constant of the first sensing circuit and the comparator threshold of the second sensing circuit causes the first switching circuit switches to open; and a second switching circuit coupled to the second sensing circuit, wherein the second switching circuit comprises second switching circuit switches that close in response to removal of the battery from the radio to dissipate the stored energy of the radio capacitor; wherein output from the inverter of the second sensing circuit causes the second switching circuit switches to close. |
