KR100541778B1 - Lcd controller having mode selection control unit employing fuse and mode selection method - Google Patents

Abstract

An LCD controller having a mode selection control unit employing a fuse and a mode selection method thereof are disclosed. The mode selection controller of the present invention controls the mode selection circuit in response to the short circuit of the fuse and the power-up signal. The mode selection controller includes an input unit for inputting a power-up signal indicating power stabilization of the LCD controller and outputting a predetermined output signal according to whether a fuse is shorted, and a latch unit for latching the output of the input unit. Is provided as a mode selection circuit. Therefore, since the mode selection control unit of the present invention is built in the LCD controller, eliminating the arrangement of the power line and thus the complicated wiring pattern arrangement on the glass substrate of the LCD device for connecting the power supply voltage or the ground voltage to the conventional mode terminal. Can be.

LCD controller, mode selection, glass substrate, power line layout, complex wiring pattern

Description

LCD controller having mode selection control unit employing fuses and its mode selection method {LCD controller having mode selection control unit employing fuse and mode selection method}

1 is a circuit diagram of a mode selection controller in a conventional LCD controller.

2 is a circuit diagram of a mode selection controller in the LCD controller according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor integrated circuit device, and more particularly, to an LCD controller having a mode selection control unit for controlling a mode of a liquid crystal display device according to whether a fuse is shorted and a mode selection method thereof.

Liquid crystal displays (hereinafter referred to as "LCDs") are characterized by being manufactured in a very thin form and driven at a low voltage to consume low power. Thanks to these features, a large number of LCD devices are widely used in various electronic devices. These electronic devices include handheld electronic calculators or digital clocks, portable telephones, laptop computers, and PDAs.

The LCD device used in the portable telephone is simply an LCD module consisting of an LCD panel and an LCD controller. The LCD controller is made of a single semiconductor integrated circuit to control the LCD panel and mounted on the LCD panel in a chip-on-glass (COG) manner. The LCD panel is composed of a liquid crystal inserted and sealed between a pair of glass substrates. The LCD controller is mounted on either of the two glass substrates that make up the LCD panel.

The LCD controller mounted on the glass substrate is aligned with the liquid crystal output wires, the input / output wires, and the power wires. The liquid crystal output wires are connected to liquid crystal output terminals of the LCD controller for outputting liquid crystal drive voltages. Liquid crystal input / output wires are connected to the input / output terminals of the LCD controller to allow various signals to be input to or output from the LCD controller. The power wires provide a power supply voltage VCC and a ground voltage GND.

 On the other hand, an LCD controller having mode terminals such as IM, ID1 / CS *, ID0 is applied with predetermined voltage levels to the mode terminals to change its internal state (operation mode or device ID information).

FIG. 1 illustrates a circuit for controlling a change in an internal state of an LCD controller, which is shown in US Patent No. 6,323,930. Referring to this, the voltage level applied to the mode terminal 41 is input to the mode selection circuit 430 through the CMOS inverter 42. The mode selection circuit 43 changes the internal state of the LCD controller in accordance with the voltage level applied to the mode terminal 41. For example, the clock synchronous serial interface mode is selected when the power supply voltage VCC is applied to the IM terminal, and the I2C mode is selected when the reference voltage VEE is applied. The ID1 / CS * and ID0 terminals are used to set the 2-bit device ID assigned to the LCD controller when the LCD controller is in I2C mode. When the LCD controller is in serial interface mode, the ID1 / CS * terminals are used as chip select signals, and the ID0 terminal is set to the device ID assigned to the LCD controller. The ID1 / CS * and ID0 terminals are always supplied with supply voltage (VCC) or reference voltage (VEE).

In order to apply a constant voltage level to the mode terminals of the LCD controller, a wiring scheme that does not cross-connect in the middle over the glass substrate of the LCD module is required. This method is different from the cross connection method in a general printed circuit board (PCB), and many complicated wiring patterns are required on the glass substrate. Accordingly, the wiring pattern arrangement is not free.

Therefore, there is a need for an LCD device that can simplify the wiring pattern and free the wiring pattern arrangement.

It is an object of the present invention to provide an LCD controller having a mode selection controller that does not require an external wiring pattern.

Another object of the present invention is to provide a mode selection method of the LCD controller.

In order to achieve the above object, a preferred LCD controller of the present invention includes a mode selection controller for controlling a mode selection circuit of the LCD controller. According to an aspect of the present invention, a mode selection controller includes: an input unit for inputting a power-up signal indicating power stabilization of an LCD controller and outputting a predetermined output signal according to whether a fuse is shorted; And a latch unit for latching an output of the input unit.

According to another aspect of the present invention, a mode selection controller includes: a PMOS transistor whose gate is connected to a power-up signal which is a power stabilization signal of an LCD controller and its source is connected to a power supply voltage; An NMOS transistor whose gate is connected to a power-up signal and whose drain is connected to the drain of the PMOS transistor; A fuse connected between the source of the NMOS transistor and a ground voltage; A latch connected to drains of the PMOS transistor and the NMOS transistor; And an inverter coupled between the latch and the mode selection circuit.

In order to achieve the above another object, the present invention provides a mode selection method of the LCD controller, comprising: shorting or cutting the fuse according to the mode of the LCD controller; Applying a power-up signal, which is a power stabilization signal of the LCD controller, to the gates of the PMOS transistor and the NMOS transistor in the PMOS transistor, the NMOS transistor, and the fuse connected in series between the power supply voltage and the ground voltage; Latching a logic level at a connection point between the PMOS transistor and the NMOS transistor; And providing the latched logic level to a mode selection circuit of the LCD controller.

Accordingly, the present invention is an LCD device for connecting a power supply voltage or a ground voltage to a conventional mode terminal because a mode selection control unit for controlling a mode selection circuit in response to a short circuit of a fuse and a power-up signal is built in the LCD controller. It is possible to eliminate the arrangement of the power lines and thus the complicated wiring pattern arrangement on the glass substrate.

DETAILED DESCRIPTION In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings that describe exemplary embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

2 is a diagram illustrating a mode selection controller according to an embodiment of the present invention. Referring to this, the mode selection controller 200 controls the mode selection circuit inside the LCD controller and is embedded in the LCD controller. The mode selection controller 200 includes a PMOS transistor 201, an NMOS transistor 202, and a fuse 203 connected in series between a power supply voltage VCC and a ground voltage GND. Gates of the PMOS transistor 201 and the NMOS transistor 202 are connected to a power-up signal PwrUP. The node NA, which is the drains of the PMOS transistor 201 and the NMOS transistor 202, is connected to the latch 204 and the inverter 205 connected in series, and the node NB, which is an output of the inverter 205, is a mode selection circuit 43. Is connected to.

The power-up signal PwrUP is initially powered up to maintain a logic low level until the power supply voltage VCC rises to a constant voltage level. When the power supply voltage VCC rises to a constant voltage level, the power supply voltage VCC level is maintained. Occurs at a logic high level. That is, the power-up signal PwrUP is selectively blown to determine the operation of the mode selection circuit 43 of the fuse 203 of the LCD controller. The mode selection circuit 43 is a mode of operation of the LCD controller, for example, serial interface mode, I2C mode. Switch to the device ID mode or the like.

The operation of the mode selection controller 200 is described as follows.

First, when the fuse 203 is connected without being cut, the PMOS transistor 201 is turned on in response to the initial logic low level of the power-up signal PwrUP, so that the node NA is at a logic high level. Node NA at logic high level is latched by latch 204 and node NB is generated at logic high level. The node NB at the logic high level is provided to the mode selection circuit 43. Thereafter, in response to the power-up signal PwrUP rising to the logic high level, the NMOS transistor 202 is turned on and a current path is formed through the fuse 203 to the ground voltage GND, so that the node NA becomes Logic low level. Node NA at the logic low level is latched by latch 204 and node NB is at the logic low level. The node NB at the logic low level is provided to the mode selection circuit 43.

Second, when the fuse 203 is disconnected, the PMOS transistor 201 is turned on in response to the initial logic low level of the power-up signal PwrUP, so that the node NA is at a logic high level and the node NB is at a logic level. Occurs at high level. The node NB at the logic high level is provided to the mode selection circuit 43. Thereafter, in response to the rise of the power-up signal PwrUP to the logic high level, the NMOS transistor 202 is turned on but no current path to the ground voltage GND is formed, so that the node NA is previously latched ( The logic high level latched by 204 is maintained and node NB is generated at a logic high level and provided to mode select circuit 43.

In the present embodiment, a predetermined logic level is applied to the mode selection circuit 43 in response to the power-up signal PwrUP depending on whether the fuse 203 is cut off. This has almost the same function as connecting the predetermined power supply voltage VCC and ground voltage GND to the mode terminals by the complex wiring pattern as described in FIG.

Therefore, according to the present invention, it is possible to set the mode of the LCD device without arranging a complicated wiring pattern for applying the power supply voltage VCC or the ground voltage GND to the conventional mode terminals.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

In the above-described present invention, since a mode selection control unit for controlling a mode selection circuit in response to a fuse short circuit and a power-up signal is built in the LCD controller, an LCD device for connecting a power supply voltage or a ground voltage to a conventional mode terminal. It is possible to eliminate the arrangement of the power lines and thus the complicated wiring pattern arrangement on the glass substrate. This simplifies the wiring pattern of the glass substrate and frees the pattern arrangement.

Claims (8)

In the LCD controller having a mode selection control unit for controlling a mode selection circuit inside the LCD controller, the mode selection control unit An input unit for inputting a power-up signal indicating power stabilization of the LCD controller and outputting a predetermined output signal according to whether a fuse is shorted; And And a latch unit for latching an output of the input unit. The method of claim 1, wherein the input unit A PMOS transistor whose source is connected to a power supply voltage and whose gate is connected to the power-up signal; An NMOS transistor having a gate connected to the power-up signal and a drain connected to a drain of the PMOS transistor; And And the fuse connected between a source of the NMOS transistor and a ground voltage. The method of claim 1, wherein the power-up signal is LCD power, characterized in that the initial power-up maintains a logic low level until the power supply voltage rises to a predetermined voltage level, when the power supply voltage rises to the predetermined voltage level is generated at a logic high level of the power supply voltage level. . The method of claim 1, wherein the mode selection control unit And an inverter between the latch and the mode selection circuit. In the LCD controller having a mode selection control unit for controlling a mode selection circuit of the LCD controller, the mode selection control unit A PMOS transistor whose gate is connected to a power-up signal which is a power stabilization signal of the LCD controller and whose source is connected to a power supply voltage; An NMOS transistor having a gate connected to the power-up signal and a drain connected to a drain of the PMOS transistor; A fuse connected between a source of the NMOS transistor and a ground voltage; A latch connected to drains of the PMOS transistor and the NMOS transistor; And And an inverter coupled between the latch and the mode selection circuit. The method of claim 5, wherein the power-up signal is LCD power, characterized in that the initial power-up maintains a logic low level until the power supply voltage rises to a predetermined voltage level, when the power supply voltage rises to the predetermined voltage level is generated at a logic high level of the power supply voltage level. . In the mode selection method of the LCD controller, Shorting or cutting a fuse according to a mode of the LCD controller; Applying a power-up signal, a power stabilization signal of the LCD controller, to the gates of the PMOS transistor and the NMOS transistor at a PMOS transistor, an NMOS transistor, and the fuse connected in series between a power supply voltage and a ground voltage; Latching a logic level at a connection point between the PMOS transistor and the NMOS transistor; And And providing the latched logic level to a mode selection circuit of the LCD controller. The method of claim 7, wherein the power-up signal is LCD power, characterized in that the initial power-up maintains a logic low level until the power supply voltage rises to a predetermined voltage level, when the power supply voltage rises to the predetermined voltage level is generated at a logic high level of the power supply voltage level. How to choose mode.

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