Area-efficient apparatus and method for sensing signal using overlap sampling time
The present invention relates to an area-efficient apparatus and method for sensing a signal using overlap sampling time. In a preferred embodiment of the present invention, the sensing apparatus sensing a signal which detects degradation of a light-emitting device and transferring the signal to a compensating circuit comprises: M switching portions connected to sensing lines included in each group of M groups into which N sensing lines are divided, where N>M and N and M are natural numbers. The switching portion is characterized by alternatively connecting any one of N/M sensing lines to a sample-and-hold portion.
1. An area-efficient sensing apparatus using overlap sampling time, sensing a signal comprising mobility or threshold voltage of a driving transistor applying a driving current to an organic light-emitting diode, comprising:
M switching portions each connected to a sensing line included in a respective group of M groups of sensing lines into which N sensing lines are divided, where N>M and N and M are natural numbers;
M sample-and-hold portions connected to the M switching portions, respectively, and each receiving a signal transferred from any one of N/M sensing lines included in the respective group of M groups of sensing lines;
a multiplexer connected to the M sample-and-hold portions; and
an analog-to-digital converting portion ADC connected to the multiplexer,
wherein each of the M switching portions alternatively connects any one of N/M sensing lines included in the respective group of M groups of sensing lines to the respective M sample-and-hold portions,
each of the M sample-and-hold portions comprises (i) a sampling capacitor C S storing a signal input from the sensing line and (ii) a sharing capacitor C SH receiving the signal stored in the sampling capacitor,
the analog-to-digital converting portion converts M signals each stored in the respective sharing capacitors by being input through one sensing line of the N/M sensing lines included in the respective group of M groups of sensing lines into digital signals in sequence, and
each of the sampling capacitors starts storing a signal input through another sensing line of the N/M sensing lines included in the respective group of M groups of sensing lines before the analog-to-digital converting portion completes digital signal conversion.
2. The area-efficient sensing apparatus of claim 1 , wherein each of the M sample-and-hold portions comprises:
a first low reference voltage V REFAL ;
a second reference voltage V REFB ;
the sampling capacitor C s connected to a first node N 1 connected to each of the M switching portions and the second reference voltage V REFB ;
the sharing capacitor C SH connected to the first node and the first low reference voltage V REFAL ; and
a plurality of switching elements.
3. The area-efficient sensing apparatus of claim 2 , wherein each of the plurality of switching elements comprises:
a first switch SW 1 formed between the sampling capacitor C s and the second reference voltage V REFB ;
a second switch SW 2 formed between the sampling capacitor C s and the first low reference voltage V REFAL ;
a third switch SW 3 formed between the first node N 1 and the sharing capacitor C SH ;
a fourth switch SW 4 formed between the sharing capacitor C SH and the first low reference voltage V REFAL ; and
a fifth switch SW 5 formed between the sharing capacitor C SH and the first high reference voltage V REFAH .
4. The area-efficient sensing apparatus of claim 1 , wherein a point of time when each of the sampling capacitors completes storing the signal input through another sensing line of the N/M sensing lines included in the respective group of M groups of sensing lines coincides approximately with a point of time when the analog-to-digital converting portion completes converting the analog signals through the one sensing line of the N/M sensing lines included in the respective group of M groups of sensing lines into the digital signals.
5. An area-efficient sensing method using overlap sampling time for sensing a signal using a sensing apparatus comprising a switching portion alternatively selecting one of a plurality of sensing lines and transferring thereof to a sample-and-hold portion, the sample-and-hold portion connected to the switching portion, and an analog-to-digital converting portion converting a signal received from the sample-and-hold portion into a digital signal, comprising:
(a) a step in which the sample-and-hold portion stores a first signal input through a first sensing line of the plurality of sensing lines connected to the switching portion;
(b) a step in which the sample-and-hold portion shares the first signal;
(c) a step in which the analog-to-digital converting portion converts the shared first signal into a digital signal; and
(d) a step in which the sample-and-hold portion starts storing a second signal input through a second sensing line of the plurality of sensing lines connected to the switching portion prior to the completion of step (c).
6. The area-efficient sensing method of claim 5 , further comprising:
a step in which the switching portion connects the first sensing line to the sample-and-hold portion prior to step (a); and
a step in which the switching portion connects a next sensing line to the sample-and-hold portion prior to step (d).
7. The area-efficient sensing method of claim 5 , further comprising:
a step in which the sample-and-hold portion shares the second signal after step (d); and
a step in which the analog-to-digital converting portion converts the second signal shared in the sample-and-hold portion into a digital signal.
8. An area-efficient sensing method for sensing a signal using a sensing apparatus comprising M switching portions, each connected to a sensing line included in a respective group of M groups of sensing lines into which N sensing lines are divided, where N>M and N and M are natural numbers, M sample-and-hold portions connected to the M switching portions, respectively, each receiving a signal transferred from any one of N/M sensing lines included in the respective group of M groups of sensing lines, and each including a sampling capacitor C S storing a signal input from the sensing line and a sharing capacitor C SH receiving the signal stored in the sampling capacitor, and an analog-to-digital converting portion converting an analog signal into a digital signal, comprising:
(a) a step in which each of the sampling capacitors stores a first signal input through a first sensing line of N/M sensing lines included in the respective group of M groups of sensing lines;
(b) a step in which each of the sharing capacitors is shared with the respective first signal;
(c) a step in which the analog-to-digital converting portion converts the first signals each stored in the respective sharing capacitors, into digital signals; and
(d) a step in which each of the sampling capacitors starts storing a second signal input through a second sensing line of the N/M sensing lines included in the respective group of M groups of sensing lines prior to the completion of step (c).
9. The area-efficient sensing method of claim 8 , further comprising:
a step in which each of the M switching portions connects the first sensing line to the respective sample-and-hold portions prior to step (a); and
a step in which each of the M switching portions connects a next sensing line included in the respective group of M groups of sensing lines to the M sample-and-hold portions, respectively, prior to step (d).
10. The area-efficient sensing method of claim 8 , further comprising:
a step in which each of the sharing capacitors receives the respective second signals after step (d); and
a step in which the analog-to-digital converting portion converts the second signals charged in the respective sharing capacitors into digital signals after the completion of step (c).