| 主权项 |
1. Circuitry for regulating a voltage, the circuitry comprising:
a regulator including an amplifier and a first transistor, the amplifier having an output node and first and second input nodes, the amplifier's output node being connected to a gate of the first transistor, the amplifier's first input node being connected to a first reference voltage, a source of the first transistor being coupled to a ground through first and second resistors in series, the source of the first transistor being connected to a line, and the amplifier's second input node being connected between the first and second resistors, wherein the regulator is to regulate an output voltage of the line in response to the first reference voltage, so that the output voltage is approximately equal to a target voltage; and pull down circuitry including a comparator and second and third transistors, the comparator having an output node and first and second input nodes, the comparator's output node being connected to operate a switch, the comparator's first input node being connected to the line, the comparator's second input node being connected to a second reference voltage, a drain of the third transistor being connected to the line and the second transistor being connected to conduct a substantially constant amount of current from a current source, wherein the pull down circuitry is to: in response to the output voltage rising above the second reference voltage, draw current from the line by the comparator operating the switch to connect a gate of the third transistor to a gate of the second transistor; and, in response to the output voltage falling below the second reference voltage by at least a predetermined amount, cease drawing the current from the line by the comparator operating the switch to turn off the third transistor, wherein the first and second reference voltages are based upon a same band gap reference as one another. |
