| 摘要 |
PROBLEM TO BE SOLVED: To provide a print head drive circuit capable of preventing a print head from erroneously operating when a power source is turned on. SOLUTION: When a main power source 1 of 42 V rises, a TR 33 is energized at a time point when VZ<SB>2</SB>of a ZD<SB>2</SB>31 reaches a voltage of 3.3 V by a current from the main power source 1 of 42 V. A voltage of 2.7 V is outputted to a logic circuit 15 from the TR 33 (the emitter terminal thereof). After that, when a switching regulator 3 is turned on, a voltage of 3.3 V is outputted from the switching regulator 3 through a TR 39, and then when a voltage of Vbe of the TR 33 is not 0.6 V, the TR 33 comes out of continuity. As a result, the voltage of 3.3 V outputted from the switching regulator 3 as an inherent power source through the TR 39 is supplied to the logic circuit 15 as a driving voltage of the logic circuit 15. COPYRIGHT: (C)2005,JPO&NCIPI
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