Configurable light source driver device
First Claim
1. An integrated circuit comprising:
- circuitry configured to place the integrated circuit in a low electro-magnetic interference (EMI) mode of operation during a first time period, and to place the integrated circuit a low power mode of operation during a second time period different from the first time period, the low EMI mode of operation characterized by placing a light source in a pulsed mode of operation when the light source is coupled to a first externally-accessible terminal of the integrated circuit and a resistor is coupled to a second externally-accessible terminal of the integrated circuit, the low power mode of operation characterized by placing the light source in the pulsed mode of operation when the light source is coupled to the first externally-accessible terminal of the integrated circuit and the second externally-accessible terminal of the integrated circuit is left unconnected; and
a resistor presence detector circuit configured to detect a presence of the resistor when coupled to the second externally-accessible terminal and to generate a first detector output signal that is provided to the circuitry for placing the integrated circuit in the low EMI mode of operation.
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Accused Products
Abstract
A configurable light source driver device includes circuitry that detects the presence of a resistor when connected to a terminal of the device and automatically configures the device to operate as a differential driver circuit with low EMI emission and a level of circuit stability that is selected on the basis of parasitic impedance conditions of the differential driver circuit. When the terminal is left unconnected, the configurable light source driver device automatically configures itself to operate as a single ended driver circuit with low power consumption and a different level of circuit stability that is selected on the basis of parasitic impedance conditions of the single ended driver circuit. Furthermore, the configurable light source driver device can include a pulse width adjustment circuit for modifying certain operating characteristics of each of the differential driver circuit and the single ended driver circuit.
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Citations
20 Claims
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1. An integrated circuit comprising:
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circuitry configured to place the integrated circuit in a low electro-magnetic interference (EMI) mode of operation during a first time period, and to place the integrated circuit a low power mode of operation during a second time period different from the first time period, the low EMI mode of operation characterized by placing a light source in a pulsed mode of operation when the light source is coupled to a first externally-accessible terminal of the integrated circuit and a resistor is coupled to a second externally-accessible terminal of the integrated circuit, the low power mode of operation characterized by placing the light source in the pulsed mode of operation when the light source is coupled to the first externally-accessible terminal of the integrated circuit and the second externally-accessible terminal of the integrated circuit is left unconnected; and a resistor presence detector circuit configured to detect a presence of the resistor when coupled to the second externally-accessible terminal and to generate a first detector output signal that is provided to the circuitry for placing the integrated circuit in the low EMI mode of operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An integrated circuit comprising:
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circuitry configured to selectively place the integrated circuit in either a low electro-magnetic interference (EMI) mode of operation or a low power mode of operation, the low EMI mode of operation characterized by placing a light source in a pulsed mode of operation when the light source is coupled to a first externally-accessible terminal of the integrated circuit and a resistor is coupled to a second externally-accessible terminal of the integrated circuit, the low power mode of operation characterized by placing the light source in the pulsed mode of operation when the light source is coupled to the first externally-accessible terminal of the integrated circuit and the second externally-accessible terminal of the integrated circuit is left unconnected, wherein the circuitry comprises; a current source; a first switch operable to place the light source in the pulsed mode of operation, the pulsed mode of operation of the light source characterized by a first pulsed current draw from a power supply; and a second switch operable to effectuate a second pulsed current draw from the power supply and through the resistor when the integrated circuit is placed in the low EMI mode of operation, the second pulsed current draw having an opposite polarity to the first pulsed current draw; a control circuit configured to provide a first switch control signal for actuating the first switch to place the light source in the pulsed mode of operation, and a second switch control signal for actuating the second switch to produce the second pulsed current, the second switch control signal having an opposite polarity to the first switch control signal; and a resistor presence detector circuit configured to detect a presence of the resistor when coupled to the second externally-accessible terminal and to generate a first detector output signal that is provided to the control circuit for placing the integrated circuit in the low EMI mode of operation. - View Dependent Claims (12, 13, 14, 15)
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16. A method of using an integrated circuit, comprising:
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making a determination to operate the integrated circuit in one of a low electro-magnetic interference (EMI) mode of operation or a low power mode of operation; when determined to operate the integrated circuit in the low EMI mode of operation, coupling a light source to a light source driver terminal of the integrated circuit and coupling a resistor to a resistor sensing terminal of the integrated circuit; when determined to operate the integrated circuit in the low power mode of operation, coupling the light source to the light source driver terminal of the integrated circuit and leaving the resistor sensing terminal of the integrated circuit unconnected; using a resistor presence detector circuit to detect the coupling of the resistor to the resistor sensing terminal and providing a detector output signal from the resistor presence detector circuit to a control circuit; and using the control circuit to place the integrated circuit in one of the low EMI mode of operation or the low power mode of operation based on the detector output signal. - View Dependent Claims (17, 18, 19, 20)
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Specification