Imaging systems with improved circuitry to provide boosted control signals
An image sensor having rows and columns of image pixels may include row control circuitry that controls voltages that are sent to each row of the image pixels. The row control circuitry may include booster circuitry that converts a positive power supply voltage (such as 2.8V) to voltages that are negative or otherwise less than the positive power supply voltage and/or greater than the positive power supply voltage. The booster circuitry may have a plurality of switches that control an input to an amplifier, thereby allowing the circuitry to produce any desired voltage in a given range. The booster circuitry output may be shared between multiple rows of the image pixels, and the produced boosted circuitry may be fed to any desired one or more of the rows of image pixels.
1. An image sensor comprising:
an array of imaging pixels having rows and columns of pixels; and
row control circuitry coupled to the rows of pixels, wherein the row control circuitry comprises booster circuitry that is shared between multiple rows of pixels, wherein the booster circuitry comprises an amplifier and a plurality of switches that are configured to produce an output voltage from a power supply voltage, and wherein the switches are configured to be placed in a first mode during pre-charge operations to output a first voltage with the booster circuitry, to be placed in a second mode during pre-charge operations to output a second voltage that is different from the first voltage, to be placed in a third mode during pre-charge operations to output a third voltage that is different from the first and second voltages, and to be placed in a fourth mode during pre-charge operations to output a fourth voltage that is different from the first, second, and third voltages.
2. The image sensor defined in claim 1 wherein the power supply voltage is 2.8V.
3. The image sensor defined in claim 2 wherein the first voltage is between −1.0V and 0V.
4. The image sensor defined in claim 3 wherein the second voltage is 0V to 2.0V.
5. The image sensor defined in claim 4 wherein the third voltage is greater than 2.0V.
6. The image sensor defined in claim 5 wherein the fourth voltage is greater than 2.8V.
7. The image sensor defined in claim 1 wherein the power supply voltage is a positive voltage and the first voltage is a negative voltage.
8. The image sensor defined in claim 7 wherein the fourth voltage is greater than the power supply voltage.
9. The image sensor defined in claim 1 wherein each row of pixels has a switch coupled to the booster circuitry, and wherein the output voltage is configured to be fed to a respective row of pixels by turning on the switch coupled to the booster circuitry.
10. An image sensor comprising:
an array of imaging pixels having rows and columns of pixels; and
row control circuitry coupled to the rows of pixels, wherein the row control circuitry comprises booster circuitry that is configured to produce output voltages from a power supply voltage, at least a first one of the output voltages is greater than the power supply voltage, and at least a second one of the output voltages is less than the power supply voltage.
11. The image sensor defined in claim 10 wherein the power supply voltage is positive.
12. The image sensor defined in claim 11 wherein the second one of the output voltages produced by the booster circuitry is negative.
13. The image sensor defined in claim 12 wherein the power supply voltage is 2.8V and wherein the second one of the output voltages is −1.0V and 0V.
14. The image sensor defined in claim 10 wherein the power supply voltage is 2.8V and the first one of the output voltages is greater than 2.8V.
15. The image sensor defined in claim 14 wherein the second one of the output voltages is between −1.0V and 2.0V.
16. An image sensor comprising:
an array of imaging pixels having rows and columns of pixels; and
row control circuitry coupled to the rows of pixels, wherein the row control circuitry comprises booster circuitry that is configured to produce a plurality of output voltages from a positive power supply voltage, wherein a first output voltage of the plurality of output voltages is negative, and wherein a second output voltage of the plurality of output voltages is greater than the positive power supply voltage.
17. The image sensor defined in claim 16 wherein the first output voltage is between −1.0V and 0V and wherein the second output voltage is greater than 2.8V.
18. The image sensor defined in claim 17 wherein the positive power supply voltage is 2.8V, a third output voltage of the plurality of output voltages is between 0V and 2.0V, and a fourth output voltage of the plurality of output voltages is greater than 2.0V.
19. The image sensor defined in claim 16 wherein each row of pixels has a switch coupled to the booster circuitry, and wherein the plurality of output voltages are configured to be fed to a respective row of pixels by turning on the switch coupled to the booster circuitry.
20. The image sensor defined in claim 19 wherein the booster circuitry is shared between multiple rows of pixels and wherein the booster circuitry comprises an amplifier and a plurality of switches that are configured to produce the plurality of output voltages.