Circuit for controlling driver strengths of data and data strobe in semiconductor device

A circuit for controlling driver strengths of a data and a data strobe in a semiconductor device comprising: a control signal generating unit which generates a first control signal in response to a first address code, generates a second control signal in response to a second address code, and generates a third control signal in response to a third address code; a data driver strength control unit which is selected in response to the first control signal, controls a driver strength of an input data in response to the second control signal, and finely adjusts the driver strength of the input data in response to the third control signal; and a data strobe driver strength control unit which is selected in response to the first control signal, controls a driver strength of an input data strobe in response to the second control signal, and finely adjusts the driver strength of the input data strobe in response to the third control signal.

BACKGROUND

1. Field of the Invention

The present invention relates to a data transmission of a semiconductor device for a high-speed operation and, more specifically, to a circuit for controlling driver strengths of a data and a data strobe in a semiconductor device capable of separately controlling strengths of a data driver and a data strobe driver to adjust a setup and hold time of a system.

2. Discussion of Related Art

With great requirement for a high-speed memory, the minimum data determining time of a data setup/hold time, which was not important in a low-speed memory, tends to be decreased into several hundreds ps unit. This condition gives a large difficulty to determination of data in the high-speed memory. In fact, a DRAM drives data (DQ) and data strobe (DQS) with the same strength, and the DQS is used as a reference signal for receiving the data in a system, which receives the data from the DRAM.

After constructing a system, a data setup/hold time required for the system exists. It is very difficult to change the setup/hold time set once in that system.

In general, in a low-speed memory, a sufficient data transmission is possible with the setup/hold time set once, but in a high-speed memory, problems may be caused. Therefore, in a high-speed memory, it may be required that the setup/hold time is re-adjusted.

If problems occur in a previously set system, strengths of data and data strobe thereof are simultaneously controlled. This conventional art will be described with reference toFIGS. 1 and 2.

In response to input of an extended mode register set (EMRS) code A1and A2, a control signal is outputted from an EMRS circuit10. In accordance with this control signal, a driver strength control signal is generated from a driver strength control unit20. A DQS driver30and a DQ driver40are simultaneously controlled by means of the driver strength control signal. As a result, DQS and DQ, of which strengths are controlled, are outputted, respectively.

FIG. 2is a detailed block diagram of the driver strength control unit20.

For example, output signals of the driver strength control unit20are classified into three kinds of signals, that is, a weak signal, a half signal and a full signal.

Since the strength of the DQS driver is not controlled or is controlled together with the strength of the DQ driver, a circuit for controlling the strength of the DQS driver is omitted in FIG.2.

A data strength control unit comprises a plurality of delay units310to380.

When a weak signal is outputted from the EMRS circuit10, the data DQ is inputted to the DQ driver40only via first to third delay units310to330.

When a half signal is outputted from the EMRS circuit10, the data DQ is inputted to the DQ driver40only via first to sixth delay units310to360.

When a full signal is outputted from the EMRS circuit10, the data DQ is inputted to the DQ driver40via first to eighth delay units310to380.

Conventionally, as described above, the strengths of the DQS driver and the DQ driver could not help being controlled at the same time. That is, since the strengths of the DQS driver and the DQ driver are controlled at the same time and in the same way, arriving times of the DQ and the DQS which is a reference for receiving the data in a party receiving the data could not be adjusted separately. For this reason, the setup/hold time could not be finely controlled in the previously set system.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention is directed to a circuit for controlling driver strengths of a data and a data strobe capable of separately controlling and finely adjusting driver strengths of a DQ and a DQS.

In order to achieve the above object, the present invention provides a circuit for controlling driver strengths of a data and a data strobe in a semiconductor device, the circuit comprising: a control signal generating unit which generates a first control signal in response to a first address code, generates a second control signal in response to a second address code, and generates a third control signal in response to a third address code; a data driver strength control unit which is selected in response to the first control signal, controls a driver strength of an input data in response to the second control signal, and finely adjusts the driver strength of the input data in response to the third control signal; and a data strobe driver strength control unit which is selected in response to the first control signal, controls a driver strength of an input data strobe in response to the second control signal, and finely adjusts the driver strength of the input data strobe in response to the third control signal.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 3is a block diagram illustrating strength control of a data driver and a data strobe driver according to a first embodiment of the present invention.

EMRS address codes A1, A2are address codes for determining which strength method should be used. That is, in accordance with the EMRS codes, the extended mode register set (EMRS) circuit100generates a weak signal, a half signal and a full signal. An address code A3is used for selectively driving a DQS driver strength control unit10and a DQ driver strength control unit120. An address code A4is used for classifying driver strengths of the DQS and DQ into up operation and down operation to control them.

For example, when the address code A3is in a high state, the DQS driver strength control unit110is selected, and when the address code A3is in a low state, the DQ driver strength control unit120is selected. When the address code A4is in a low state, the driver strengths of the DQ and the DQS are adjusted small by means of a down switching operation, and when the address code A4is in a high state, the driver strengths of the DQ and the DQS are adjusted largely by means of an up switching operation.

FIG. 4is a block diagram illustrating a strength control of the data driver and the data strobe driver according to a second embodiment of the present invention.

The address codes A1and A2are inputted to the EMRS circuit200, and the address codes A3and A4are inputted to a test mode control unit210.

Since all the operations except for the test mode operations are equal to those ofFIG. 3, only the test mode operation will be described.

In a test mode operation, when a test mode is activated due to a test mode enable signal E1, the DQ and the DQS are supplied to the DQS driver and the DQ driver without adjustment of driver strengths of the DQ and the DQS, so that the DQS driver and the DQ driver are driven at the same timing and slope.

After the test mode, the DQS driver strength control unit220and the DQ driver strength control unit230are selectively driven in accordance with the address codes A1, A2, A3and A4, so that the driver strength of the input DQS or DQ is controlled.

FIG. 5is a detailed circuit diagram of the DQ driver strength control unit ofFIGS. 3 and 4.

The DQ driver and the DQS driver have the same structure, and the DQ driver strength control unit and the DQS driver strength control unit have also the same structure.

For example, when a weak signal is outputted from the EMRS circuit100or200, pass gates T1, T11, T12and T4are turned on. As a result, the data (DQ) is inputted to the DQ driver700via delay units410and420.

At that time, when the address code A4is in a low state, pass gate T12which has been turned on due to the output signal from the EMRS circuit200corresponding thereto is turned off, so that the data (DQ) is inputted to the DQ driver700only via the delay unit410.

When the address code A4is in a high state, pass gates T11, T12and T13are turned on due to the output signal from the EMRS circuit200corresponding thereto, so that the data (DQ) is inputted to the DQ driver700via the delay units410to430.

For example, when a half signal is outputted from the EMRS circuit100or200, pass gates T2, T21, T22and T5are turned on. As a result, the data (DQ) is inputted to the DQ driver700via the delay units510to550.

At that time, when the address code A4is in a low state, the pass gate T22which has been turned on due to the output signal from the EMRS circuit200corresponding thereto is turned off, so that the data (DQ) is inputted to the DQ driver700only via the delay units510to540.

When the address code A4is in a high state, the pass gates T21, T22and T23are turned on due to the output signal from the EMRS circuit200corresponding thereto, so that the data (DQ) is inputted to the DQ driver700via the delay units510to560.

For example, when a full signal is outputted from the EMRS circuit100or200, pass gates T3, T31, T32and T6are turned on. As a result, the data (DQ) is inputted to the DQ driver700via the delay units610to680.

At that time, when the address code A4is in a low state, the pass gate T32which has been turned on due to the output signal from the EMRS circuit200corresponding thereto is turned off, so that the data (DQ) is inputted to the DQ driver700only via the delay units610to670.

When the address code A4is in a high state, the pass gates T31, T32and T33are turned on due to the output signal from the EMRS circuit200corresponding thereto, so that the data (DQ) is inputted to the DQ driver700via the delay units610to690.

FIG. 6is a detailed circuit diagram of the DQS driver strength control unit ofFIGS. 3 and 4.

For example, when a weak signal is outputted from the EMRS circuit100or200, the pass gates T1, T11, T12and T4are turned on. As a result, the data (DQ) is input to the DQS driver800via the delay units410and420.

At that time, when the address code A4is in a low state, the pass gate T12which has been turned on due to the output signal from the EMRS circuit200corresponding thereto is turned off, so that the data strobe (DQS) is inputted to the DQS driver800only via the delay unit410.

When the address code A4is in a high state, the pass gates T11, T12and T13are turned on due to the output signal from the EMRS circuit200corresponding thereto, so that the data strobe (DQS) is inputted to the DQS driver800via the delay units410to430.

For example, when a half signal is outputted from the EMRS circuit100or200, the pass gates T2, T21, T22and T5are turned on. As a result, the data strobe (DQS) is inputted to the DQS driver800via the delay units510to550.

At that time, when the address code A4is in a low state, the pass gate T22which has been turned on due to the output signal from the EMRS circuit200corresponding thereto is turned off, so that the data strobe (DQS) is inputted to the DQS driver800only via the delay units510to540.

When the address code A4is in a high state, the pass gates T21, T22and T23are turned on due to the output signal from the EMRS circuit200corresponding thereto, so that the data strobe (DQS) is inputted to the DQS driver800via the delay units510to560.

For example, when a full signal is outputted from the EMRS circuit100or200, the pass gates T3, T31, T32and T6are turned on. As a result, the data strobe (DQS) is input to the DQS driver800via the delay units610to680.

At that time, when the address code A4is in a low state, the pass gate T32which has been turned on due to the output signal from the EMRS circuit200corresponding thereto is turned off, so that the data strobe (DQS) is input to the DQS driver800only via the delay units610to670.

When the address code A4is in a high state, the pass gates T31, T32and T33are turned on due to the output signal from the EMRS circuit200corresponding thereto, so that the data strobe (DQS) is input to the DQS driver800via the delay units610to690.

Although the EMRS circuit has been described as an example in the above embodiments of the present invention, a mode register set (MRS) circuit may be used.

As described above, the present invention is available in both of a high-speed dram and a low-speed dram, and it is possible to efficiently adjust the setup/hold time of a system, by adjusting the DQ and DQS driver strengths in combination of the MRS, EMRS or other codes.

In addition, according to the present invention, it is possible to separately control and finely control the DQ and DQS driver strengths.

Although the foregoing description has been made with reference to the preferred embodiments, it is to be understood that changes and modifications of the present invention may be made by the ordinary skilled in the art without departing from the spirit and scope of the present invention and appended claims.