LED drive circuit for pulse oximetry and method for using same
First Claim
Patent Images
1. An LED drive circuit for a pulse oximeter comprising:
- a first current mirror configured to supply a first current to activate a first LED of a pulse oximetry sensor, wherein the first current mirror comprises three NPN bipolar junction transistors (BJTs), wherein a first and second NPN BJTs of the current mirror have their respective base leads electrically coupled together, wherein the first NPN BJT of the current mirror is coupled to a DAC output of a microcontroller.
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Abstract
In various embodiments, there is provided an LED drive circuit and a method for using the same. Specifically, the present disclosure is directed to an LED drive circuit for pulse oximeters. In an embodiment, the LED drive circuit includes a current mirror configured to provide drive current to an LED of a sensor. Additionally, the method includes providing current to first and second current mirrors, wherein the first and second current mirrors are configured to control first and second light sources.
881 Citations
19 Claims
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1. An LED drive circuit for a pulse oximeter comprising:
a first current mirror configured to supply a first current to activate a first LED of a pulse oximetry sensor, wherein the first current mirror comprises three NPN bipolar junction transistors (BJTs), wherein a first and second NPN BJTs of the current mirror have their respective base leads electrically coupled together, wherein the first NPN BJT of the current mirror is coupled to a DAC output of a microcontroller. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A pulse oximetry monitor comprising:
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a light drive circuit comprising; a first current mirror drive circuit with a first current input; a second current mirror drive circuit with a second current input, wherein the first and second current mirror drive circuits are configured to alternately supply current to at least two LEDs; and wherein the first current mirror drive circuit or the second current mirror drive circuit, or both, are configured to amplify a DAC output current provided by a microcontroller. - View Dependent Claims (11, 12, 13, 14)
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15. A method of operating a pulse oximeter light drive circuit comprising:
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providing a first current to a first current mirror, the first current mirror configured to control a first light source; providing a second current to a second current mirror, the second current mirror configured to control a second light source; and turning off current to both the first and second current mirrors for a period after each instance of either the first or second current mirrors being turned on; wherein providing first and second currents comprises providing first and second DAC output currents from a microcontroller. - View Dependent Claims (16)
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17. An LED drive circuit for a pulse oximeter comprising:
a current mirror configured to supply a current to activate an LED of a pulse oximetry sensor, wherein the current mirror is coupled to a DAC output of a microcontroller.
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18. A pulse oximetry monitor comprising:
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a light drive circuit comprising; a first current mirror drive circuit with a first current input; and a second current mirror drive circuit with a second current input, wherein the first and second current mirror drive circuits are coupled to a DAC output of a microcontroller and configured to alternately supply current to at least two LEDs.
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19. A method of operating a pulse oximeter light drive circuit comprising:
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providing a first current to a first current mirror, the first current mirror configured to control a first light source, wherein the first current comprises a first DAC output current from a microcontroller; providing a second current to a second current mirror, the second current mirror configured to control a second light source, wherein the second current comprises a second DAC output current from the microcontroller; and turning off current to both the first and second current mirrors for a period after each instance of either the first or second current mirrors being turned on.
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Specification