Comparator unit, display, and method of driving display
A comparator unit includes: a comparison section configured to compare a control pulse with an electric potential based on a signal voltage; and a control section configured to control, based on the control pulse, operation and non-operation of the comparison section.
1. A comparator unit comprising:
comparison circuitry configured to compare a control pulse with an electric potential based on a signal voltage; and
control circuitry configured to control, based on the control pulse, operation and non-operation of the comparison circuitry, wherein
the comparison circuitry includes a signal writing transistor configured to receive the signal voltage, an inverter circuit, and a capacitor configured to include an input point and an output point, and compares a voltage of the output point with a predetermined voltage,
the control circuitry is configured to receive the control pulse, and to perform ON-OFF operation based on a signal of a phase opposite to a phase of a signal used by the signal writing transistor, and
the capacitor is configured to retain, based on operation of the signal writing transistor, the electric potential based on the signal voltage, the input point being connected to the signal writing transistor and the control-pulse transistor, and the output point being connected to the inverter circuit.
2. The comparator unit according to claim 1 , wherein
the control pulse has sawtooth-waveform voltage variation, and
the control circuitry includes a first switching circuit, the first switching circuit being connected in series to the inverter circuit, the control circuitry being configured to perform ON-OFF operation based on the sawtooth-waveform voltage variation of the control pulse.
3. The comparator unit according to claim 2 , wherein the control circuitry includes a second switching circuit connected in parallel to the first switching circuit, and configured to be in an ON state during an operation period of the comparator unit.
4. The comparator unit according to claim 2 , wherein the control circuitry includes a resistive element connected in series to the inverter circuit.
5. The comparator unit according to claim 2 , wherein the control circuitry includes a constant current source connected in series to the inverter circuit, and configured to suppress a current flowing through the inverter circuit.
6. The comparator unit according to claim 5 , wherein
the inverter circuit includes inverters in two-or-more-stage cascade connection, and
the constant current source is connected to the inverter of a first stage on a side, with respect to the inverter of the first stage, where one of a power supply on high potential side and a power supply on low potential side is provided, and the constant current source is connected to the inverter of a second stage on a side, with respect to the inverter of the second stage, where the other of the power supply on the high potential side and the power supply on the low potential side is provided.
7. The comparator unit according to claim 1 , wherein the comparison circuitry includes
a differential circuit configured to receive the signal voltage and the control pulse as two inputs, and
a constant current source configured to supply a constant current to the differential circuit.
8. The comparator unit according to claim 7 , wherein the capacitor is connected to the signal writing transistor, and is configured to retain, based on operation of the signal writing transistor, the electric potential based on the signal voltage.
9. The comparator unit according to claim 7 , wherein
the control pulse has sawtooth-waveform voltage variation, and
the control circuitry includes a third switching circuit connected in series to the constant current source, and configured to perform ON-OFF operation based on the sawtooth-waveform voltage variation of the control pulse.
10. The comparator unit according to claim 9 , wherein the control circuitry includes a second switching circuit connected in series to a constant-voltage circuit, and configured to perform ON-OFF operation based on the sawtooth-waveform voltage variation of the control pulse, the constant-voltage circuit being configured to apply a constant voltage to a gate electrode of a transistor configuring the constant current source.
11. A display comprising a plurality of pixels arranged in a two-dimensional matrix, the pixels each including a light-emission section and a drive circuit configured to drive the light-emission section,
the drive section including
a comparator unit configured to compare a control pulse with an electric potential based on a signal voltage, and to output a predetermined voltage based on a comparison result, and
a light-emission-section driving transistor configured to supply a current to the light-emission section in response to the predetermined voltage from the comparator unit, thereby allowing the light-emission section to emit light, and
the comparator unit including
comparison circuitry configured to compare a control pulse with an electric potential based on a signal voltage, and
control circuitry configured to control, based on the control pulse, operation and non-operation of the comparison circuitry, wherein
the comparison circuitry includes a signal writing transistor configured to receive the signal voltage, an inverter circuit, and a capacitor configured to include an input point and an output point, and compares a voltage of the output point with a predetermined voltage,
the control circuitry is configured to receive the control pulse, and to perform ON-OFF operation based on a signal of a phase opposite to a phase of a signal used by the signal writing transistor, and
the capacitor is configured to retain, based on operation of the signal writing transistor, the electric potential based on the signal voltage, the input point being connected to the signal writing transistor and the control-pulse transistor, and the output point being connected to the inverter circuit.
12. The display according to claim 11 , wherein
the plurality of pixels are arranged in a two-dimensional matrix in a first direction and a second direction, and are divided into a P-number of pixel blocks in the first direction, and
the light-emission sections configuring pixels belonging to first to P-th pixel blocks are allowed to emit light simultaneously on a pixel-block basis sequentially in order from the first to P-th pixel blocks, and when the light emission sections configuring the pixels belonging to part of the pixel blocks are allowed to emit light, the light emission sections configuring the pixels belonging to rest of the pixel blocks are not allowed to emit light.
13. The display according to claim 11 , wherein the light-emission section emits light a plurality of times based on a plurality of the control pulses.
14. The display according to claim 11 , wherein number of the control pulses supplied to the drive circuits in one display frame is less than number of the control pulses in one display frame.
15. The display according to claim 11 , wherein light is emitted constantly from any of the pixel blocks in one display frame.
16. The display according to claim 11 , wherein the pixel block from which no light is emitted is present in one display frame.
17. The display according to claim 11 , wherein an absolute value of a voltage of each of the control pulses increases and then decreases over time.
18. The display according to claim 11 , wherein the light-emission section includes a light emitting diode.
19. A method of driving a display with a plurality of pixels arranged in a two-dimensional matrix, the pixels each including a light-emission section and a drive circuit configured to drive the light-emission section, the drive section including a comparator unit that includes control circuitry and comparison circuitry, wherein the comparison circuitry includes a signal writing transistor, an inverter circuit, and a capacitor configured to include an input point and an output point, the light-emission-section section including a driving transistor configured to supply a current to the light-emission section in response to the predetermined voltage from the comparator unit, thereby allowing the light-emission section to emit light,
the method comprising:
comparing, by the comparison circuitry, a control pulse with an electric potential based on a signal voltage;
controlling, by the control circuitry, and based on the control pulse, operation and non-operation of the comparator unit;
receiving, by the signal writing transistor, the signal voltage;
receiving, by the control circuitry, the control pulse, and performing ON-OFF operation based on a signal of a phase opposite to a phase of a signal used by the signal writing transistor; and
comparing, by the comparison circuitry, a voltage of the output point with a predetermined voltage, and
retaining, by the capacitor, based on operation of the signal writing transistor, the electric potential based on the signal voltage, the input point being connected to the signal writing transistor and the control-pulse transistor, and the output point being connected to the inverter circuit.