Reference voltage generating circuit and generating method, display drive circuit and display

Abstract

A reference voltage generation circuit for driving a liquid crystal display comprises a positive polarity ladder resistor circuit including a first ladder resistor circuit (212) between first and second power source lines supplied with first and second power source voltages (VDD, VSS), respectively, and a negative polarity ladder resistor circuit including a second ladder resistor circuit (222) between the first and second power source lines. First to i-th reference voltage output switching circuits (VSW1-VSWi) are respectively inserted between first to i-th division nodes (ND 1 -ND i ) of the first ladder resistor circuit (212), where i is an integer larger than or equal to 2, and first to i-th reference voltage output nodes (VND 1 -VND i ). (i + 1)th to 2i-th reference voltage output switching circuits (VSW(i+1)-VSW2i) are respectively inserted between (i + 1)th to 2i-th division nodes (ND i+1 -ND 2i ) of the second ladder resistor circuit and the first to i-th reference voltage output nodes. When polarity inversion of a voltage outputted by a polarity inversion drive system at a given polarity inversion period is repeated, the first to i-th reference voltage output switching circuits are switched on during a positive polarity driving period and switched off during a negative polarity driving period; and the (i + 1)th to 2i-th reference voltage output switching circuits are switched off during the positive polarity driving period and switched on during the negative polarity driving period.

Description

technical field [0001] The invention relates to a reference voltage generating circuit, a display driving circuit, a display device and a reference voltage generating method. technical background [0002] Display devices typified by electro-optical devices such as liquid crystal devices are required to be smaller in size and higher in precision. Most of these liquid crystal devices achieve low power consumption and are mounted on portable electronic devices. For example, when mounted as a display unit of a mobile phone, image display with rich hues by multi-coloring is required. [0003] In general, a video signal used for image display is gamma-corrected according to display characteristics of a display device. This gamma correction is implemented by a gamma correction circuit (a reference voltage generation circuit in a broad sense). Taking a liquid crystal device as an example, a gamma correction circuit generates a voltage corresponding to the transmittance of a pixel...

AI Technical Summary

Problems solved by technology

Therefore, the power supply voltage into which the ladder-shaped resistors are inserted is alternately applied according to the polarity inversion cycle, and thus the required charge and discharge time cannot be fully guaranteed, and the resistance ratio of the ladder-shaped resistors must be small

In this way, the current flowing through the ladder resistor will increase, resulting in an increase in power consumption

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