| 摘要 |
A high luminance LED fresh module of a camera phone using a low power driving circuit is provided to reduce a fabrication cost by simplifying a circuit construction. Upon being connected with battery power of 3.3V~4.2V, a voltage setting unit(210) sets a reference voltage for driving a power MOSFET(MOS Field Effect Transistor)(230) for a rail-to-rail OP amplifier(200) in driving a photograph mode, a standby mode and a fresh mode by a controller(100). A rail-to-rail OP amplifier(220) controls the power MOSFET(230) with a comparison set value output value obtained by applying a voltage divided by a reference voltage source to a positive (+) input terminal of the OP amplifier(220) and voltage detected from a current detection resistor(Rcs) to a negative (-) input terminal of the OP amplifier(220). The power MOSFET(230) includes a drain to which one side of a power LED is connected, a source connected with the current detection resistor(Rcs) and a gate to which the rail-to-rail OP amplifier(220) is connected.
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