| 摘要 |
A low-noise current source driver for a laser diode load is achieved by means of a current-regulated supply connected across the load, and a shunt regulator. The shunt regulator comprises a shunting element, a current sensing element for sensing current conducted through the load, and an error amplifier responsive to a difference between the current sensed by the current sensing element and a first reference current. The current regulator is designed to respond to a signal a signal representative of a second reference current to produce an appropriate corresponding output current. The shunting element is connected across the power supply and load, and is controlled by the error amplifier to conduct all current from the current regulated supply in excess of the first reference current. The second reference current is greater than the first reference current by an amount sufficient to ensure that noise and ripple currents cannot cause the output of the current-regulated supply to drop below the first reference current.
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