Comparator circuit, comparator circuit control method, A/D conversion circuit, and display apparatus

Patent metadata

Field	Value
Publication number	US-9608614-B2
Application number	US-201414576824-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 27, 2013
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

A comparator circuit includes a differential circuit unit which detects a difference between two input signals, a current supply unit which supplies a current to the differential circuit unit, and a control unit which detects an operation timing of the differential circuit unit and controls the current supplied to the differential circuit unit by the current supply unit according to a detection result thereof.

First claim

What is claimed is:

1. A comparator circuit, comprising:
a differential circuit configured to detect a difference between two input signals;
a current supply configured to supply a current to the differential circuit; and
a control circuit configured to detect an operation timing of the differential circuit and to control the current supplied to the differential circuit by the current supply according to a detection result thereof,
wherein the current supply is arranged to selectively supply a first current at a first time and a second current at a second time which is lower than the first current to the differential circuit;
wherein the control circuit is configured to control the current supply to supply the second current when the differential circuit is in a standby state, and to switch a supply of the second current to a supply of the first current before the differential circuit is shifted from the standby state to an operating state; and
wherein the differential circuit includes a differential amplifier arranged to output a signal according to the difference between the two input signals, and a first amplifier having a first threshold voltage, to which an output signal of the differential amplifier is input, and
the control circuit includes a second amplifier having a second threshold voltage lower than the first threshold voltage of the first amplifier, to which the output signal of the differential amplifier is input, wherein an output from the second amplifier is coupled to the current supply to control the current supply to switch between the first current and the second current according to an output signal of the second amplifier.

2. A comparator circuit, comprising:
a differential circuit configured to detect a difference between two input signals;
a current supply configured to supply a current to the differential circuit; and
a control circuit configured to detect an operation timing of the differential circuit and to control the current supplied to the differential circuit by the current supply according to a detection result thereof, wherein the current supply is arranged to selectively supply a first current at a first time and a second current at a second time which is lower than the first current to the differential circuit, wherein the current supply comprises:
a first source of current configured to supply the first current;
a current limiter configured to constrain the first current supplied from the first source of current to the second current; and
a switch circuit arranged to selectively short-circuit between an input end and an output end of the current limiter, and
wherein the control circuit is configured to control the switch circuit to be in an OFF state when the differential circuit is in the standby state, and to be in an ON state before the differential circuit is shifted from the standby state to an operating state.

3. The comparator circuit according to claim 2 ,
wherein the first source of current includes a first transistor having a channel length corresponding to the first current, and
the current limiter includes a second transistor having a channel length longer than the channel length of the first transistor, and is connected serially to the first transistor and in parallel to the switch circuit.

4. The comparator circuit according to claim 2 ,
wherein the first source of current includes a first transistor configured to be biased at a first bias voltage at a first gate electrode to provide the first current, and
the current limiter includes a third transistor configured to be biased at a second bias voltage at a third gate electrode to constrain the first current supplied from the first transistor and provide the second current, wherein the third transistor is connected serially to the first transistor, and is connected in parallel to the switch circuit.

5. A comparator circuit, comprising:
a differential circuit configured to detect a difference between two input signals;
a current supply configured to supply a current to the differential circuit; and
a control circuit configured to detect an operation timing of the differential circuit and to control the current supplied to the differential circuit by the current supply according to a detection result thereof, wherein the current supply is arranged to selectively supply a first current at a first time and a second current at a second time which is lower than the first current to the differential circuit,
wherein the current supply includes a first source of current for supplying the second current, and a second source of current arranged to provide a third current that is added to the second current to provide the first current, and
the control circuit is configured to control the second source of current to be in a low state when the differential circuit is in the standby state, and to be in a high state before the differential circuit is shifted from the standby state to an operating state.

6. The comparator circuit according to claim 5 ,
wherein the first source of current includes a first transistor configured to be biased at a first bias voltage corresponding to the second current, and
the second source of current includes a second transistor connected in parallel to the first transistor, and is configured to output the third current at a time of the high state.

7. The comparator circuit according to claim 5 , wherein the second source of current is configured to selectively reduce the supply of the current with respect to the differential circuit in a predetermined period during which the differential circuit is in the low state.

8. The comparator circuit according to claim 7 ,
wherein the differential circuit includes a differential amplifier configured to output a signal according to the difference between the two input signals, and
the second source of current includes a first switch circuit configured to be in a first state according to a control waveform to reduce the supply of the current to the differential amplifier in the predetermined period during which the differential circuit is in the low state.

9. The comparator circuit according to claim 8 , wherein the second source of current includes a second switch circuit configured to stabilize an output voltage of the differential circuit by performing an ON/OFF operation.

10. The comparator circuit according to claim 1 , wherein the control circuit includes a third amplifier having a threshold voltage higher than the threshold voltage of the first amplifier, to which the output signal of the differential amplifier is input, and wherein the control circuit is configured to control the current supply to switch between the first current and the second current according to the output signal of the second amplifier and an output signal of the third amplifier.

11. The comparator circuit according to claim 1 , wherein the comparator circuit is configured to receive a projection signal as a first input signal of the two input signals and a control waveform having a voltage change of a saw tooth waveform as a second input signal of the two input signals.

12. A display apparatus comprising a plurality of pixels arranged in a two-dimensional matrix, light emitting units, and driving circuits for driving the light emitting units, wherein the driving circuits include:
a comparator circuit configured to compare a signal voltage and a control waveform; and
a driving transistor configured to drive a light emitting unit according to an output of the comparator circuit, wherein the comparator circuit includes:
a differential circuit configured to detect a difference between the signal voltage and the contr

Assignees

• Sony Corp
• Sony Semiconductor Solutions Corp

Inventors

• Sugiyama Takaaki
• Kitamura Ken
• Yoshioka Masaki
• Kikuchi Ken

Classifications

• H03K5/2481 Primary

  with at least one differential stage · CPC title

• G09G2370/08

  Details of image data interface between the display device controller and the data line driver circuit · CPC title

• G09G2310/066

  Waveforms comprising a gently increasing or decreasing portion, e.g. ramp · CPC title

• G09G2310/0297

  Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns · CPC title

• G09G3/3233

  with pixel circuitry controlling the current through the light-emitting element · CPC title