Image sensor synchronization without input clock and data transmission clock
The disclosure extends to systems and methods for reducing the area of an image sensor by reducing the imaging sensor pad count used for data transmission and clock generation.
1. An endoscopic system for use in a light deficient environment comprising:
an endoscope comprising an image sensor located at a distal end of the endoscope;
a control circuit in electronic communication with the image sensor;
wherein the image sensor comprises:
a plurality of bidirectional data pads wherein there is no dedicated input synchronization clock pad, such that a number of bidirectional pads is reduced thereby reducing an area of the image sensor;
wherein electronic communication through each of the bidirectional pads is performed in three defined phases of a frame period:
a rolling-readout phase during which image data is output from the image sensor through the bidirectional pads to the control circuit,
a service-line phase during which non-image data is output from the image sensor through the bidirectional pads to the control circuit, and
a configuration phase during which image sensor configuration data is received by the image sensor from the control circuit through the bidirectional pads,
wherein signal transitions are encoded within pixel data that is output from the image sensor in correspondence to the defined phases of the bidirectional pads by adding an additional bit to the pixel data, where the additional bit is an inverted version of a specified bit out of a plurality of bits in the pixel data.
2. The endoscopic system of claim 1 , wherein the output data comprises signal transitions as service lines within frame data.
3. The endoscopic system of claim 1 , wherein a camera unit clock is used to synchronize incoming sensor data.
4. The endoscopic system of claim 1 , wherein a data recovery circuit is used to lock on incoming sensor data to keep it synchronized.
5. The endoscopic system of claim 1 , further comprising at least one transition within each of a plurality of pixel data values created within a pixel array of the image sensor.
6. The endoscopic system of claim 5 , further comprising at least one transition during a series of the plurality of pixel data values created by the pixel array.
7. The endoscopic system of claim 5 , further comprising a plurality of transitions within each of the plurality of pixel data values created by the pixel array.
8. The endoscopic system of claim 1 , wherein pixel data in at least one pixel data value is replaced with clock signal data for synchronization.
9. The endoscopic system of claim 1 , wherein pixel data in at least one pixel data value is replaced with clock signal data within at least one service line phase of one frame period.
10. The endoscopic system of claim 1 , wherein pixel data in at least one pixel data value is replaced with clock signal data within the service line phase just prior to the rolling-readout phase.
11. The endoscopic system of claim 1 , wherein clock signal data is transmitted during all frame period phases except during the rolling-readout phase.
12. The endoscopic system of claim 1 , further comprising a Phase Lock Loop built with blocks of the image sensor and blocks of the camera unit.
13. The endoscopic system of claim 12 , further comprising data lines and configuration lines electrically connecting together image sensor Phase Lock Loop blocks and camera unit Phase Lock Loop blocks.
14. The endoscopic system of claim 13 , wherein a camera unit clock and a data recovery circuit are used to lock on to incoming sensor data.
15. The endoscopic system of claim 1 , further comprising bidirectional data pads to issue image data during a defined portion of the frame timing.
16. The endoscopic system of claim 15 , wherein the data pads issue a plurality of types of data during and corresponding to a plurality of portions of frame data output.
17. The endoscopic system of claim 16 , wherein the data pads are configured to switch direction and receive commands from external system components during the configuration phase of the frame period while in receive mode.
18. The endoscopic system of claim 1 , further comprising a Phase Loop Lock based on a charge pump for driving a Voltage Controlled Oscillator.
19. The endoscopic system of claim 18 , further comprising Phase Loop Lock based on a Digital to Analog Convertor for driving the Voltage Controlled Oscillator.
20. The endoscopic system of claim 1 , further comprising a sensor configuration register to store changes in resultant operating frequency.
21. The endoscopic system of claim 1 , further comprising a local oscillator as a Phase Lock Loop reference clock.
22. The endoscopic system of claim 1 , wherein the plurality of bits representing the pixel data value include a most significant bit and a least significant bit.
23. The endoscopic system of claim 22 , wherein the most significant bit is transmitted first and the least significant bit is transmitted last.
24. The endoscopic system of claim 23 , wherein the additional bit is added after the least significant bit and is an inverted version of the least significant bit.