| 摘要 |
<p>A photometer (10) includes a light source (12) operable to direct light toward a sample (14), a detection circuit (16) operable to detect light after it has passed through the sample (14), and a drive circuit (18) for powering the light source (12). The drive circuit (18) includes an input (20) for coupling with a source of power, and energy storage circuitry (22) coupled with the input (20). The energy storage circuitry (22) is operable to store energy from the source of power when switched to a charging state, and to deliver current to the light source (12) in a ramped manner when switched to a discharge state so that the current peaks at a selected time. The drive circuit (18) delivers a controlled amount of current to the light source (12) that peaks only after the detection circuit (16) has settled so that power is not wasted at the startup of the oximeter (10).</p> |
