Light emitting diode driver and image forming device including the same
First Claim
1. A light emitting diode driver arranged to supply a drive current to a light emitting diode, the light emitting diode arranged with a photo detector that forms a monitor signal based on a radiant output that is formed by the light emitting diode, the drive current comprising a first current and a second current and formed by comparing the monitor signal and a level control signal to form a comparison signal;
- providing a buffered output signal based on the comparison signal;
providing a voltage difference based on the buffered output signal and the drive current'"'"'s nodal voltage;
forming the first current based on the voltage difference and a resistor;
providing an amplified signal based on the voltage difference; and
providing the second current based on the amplified signal.
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Accused Products
Abstract
A light emitting diode driver is arranged to supply a drive current to a light emitting diode. The light emitting diode forms a radiant output and is arranged with a photo detector that forms a monitor signal based on the radiant output. The drive current comprises a first current and a second current. A comparison signal is formed by comparing the monitor signal and a level control signal. A buffered output signal is provided based on the comparison signal. The first current is provided based on the buffered output signal. A difference voltage is formed based on the first current. An amplified signal is provided based on the difference voltage. The second current is provided based on the amplified signal.
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Citations
34 Claims
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1. A light emitting diode driver arranged to supply a drive current to a light emitting diode, the light emitting diode arranged with a photo detector that forms a monitor signal based on a radiant output that is formed by the light emitting diode, the drive current comprising a first current and a second current and formed by comparing the monitor signal and a level control signal to form a comparison signal;
- providing a buffered output signal based on the comparison signal;
providing a voltage difference based on the buffered output signal and the drive current'"'"'s nodal voltage;
forming the first current based on the voltage difference and a resistor;
providing an amplified signal based on the voltage difference; and
providing the second current based on the amplified signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- providing a buffered output signal based on the comparison signal;
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11. A light emitting diode driver arranged to supply a drive current to a light emitting diode, the light emitting diode arranged with a photo detector that forms a monitor signal based on a radiant output that is formed by the light emitting diode, the drive current comprising a first current and a second current;
- the first current formed by a voltage difference across a resistor;
the voltage difference formed by drive current'"'"'s nodal voltage and a high speed, buffer output;
the high-speed buffer output formed by a comparison signal;
the comparison signal formed by comparing the monitor signal and a level control signal; and
the second current provided by a current source whose input terminal is driven by an operational amplifier, the operational amplifier having an input signal that is the voltage difference formed by drive current'"'"'s nodal voltage and the high speed buffer output. - View Dependent Claims (12, 13, 14, 15, 16)
- the first current formed by a voltage difference across a resistor;
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17. An image forming device comprising a light emitting diode driver, the light emitting diode driver arranged to supply a drive current to a light emitting diode, the light emitting diode arranged with a photo detector that forms a monitor signal based on a radiant output that is formed by the light emitting diode, the drive current comprising a first current and a second current and formed by comparing the monitor signal and a level control signal to form a comparison signal;
- providing a buffered output signal based on the comparison signal;
forming a voltage difference based on the buffered output signal and the drive current nodal voltage;
providing the first current based on the voltage difference and a resistor;
providing an amplified signal based on the difference voltage; and
providing the second current based on the amplified signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
- providing a buffered output signal based on the comparison signal;
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28. An image forming device comprising a light emitting diode driver, the light emitting diode driver arranged to supply a drive current to a light emitting diode, the light emitting diode arranged with a photo detector that forms a monitor signal based on a radiant output that is formed by the light emitting diode, the drive current comprising a first current and a second current;
- the first current formed by a voltage difference across a resistor;
the voltage difference formed by drive current'"'"'s nodal voltage and a high speed buffer, output;
the high-speed buffer output formed by a comparison signal;
the comparison signal formed by comparing the monitor signal and a level control signal; and
the second current provided by a current source whose input terminal is driven by an operational amplifier, the operational amplifier having an input signal that is the voltage difference formed by drive current'"'"'s nodal voltage and the high speed buffer output. - View Dependent Claims (29, 30, 31, 32, 33, 34)
- the first current formed by a voltage difference across a resistor;
Specification