| 摘要 |
PROBLEM TO BE SOLVED: To provide a load drive circuit which prevents thermal damage to a switching element used for the load drive circuit, when the disconnection of wiring is caused between a temperature detecting element and an overheat protection circuit. SOLUTION: The load drive circuit includes the switching element (3) connected in series with a DC power supply (V<SB>CC</SB>) and a load (4); a drive circuit (5) to generate a control signal which turns on/off the switching element (3); the temperature detecting element (6) to detect a temperature of the switching element (3); the overheat protection circuit (7) to generate an overheat detection signal when the temperature detecting element (6) detects a temperature not lower than a predetermined temperature; and a disconnection detection circuit (11) having a current mirror circuit (12) which is connected to one and the other terminal of the temperature detecting element (6), and detects disconnection between the temperature detecting element (6) and the overheat protection circuit (7). When the overheat protection circuit (7) generates the overheat detection signal, or when the disconnection detection circuit (11) detects the disconnection between the temperature detecting element (6) and the overheat protection circuit (7), the control signal of the drive circuit (5) to the switching element (3) is suspended. COPYRIGHT: (C)2008,JPO&INPIT
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