Electricity: power supply or regulation systems – Output level responsive – Using a three or more terminal semiconductive device as the...
Reexamination Certificate
2000-05-02
2001-04-17
Riley, Shawn (Department: 2838)
Electricity: power supply or regulation systems
Output level responsive
Using a three or more terminal semiconductive device as the...
C323S267000
Reexamination Certificate
active
06218817
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Taiwan application serial no. 88211845, filed Jul. 15, 1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to voltage supply means, and more particularly, to a voltage-switching regulator with built-in voltage-switching module for supplying a terminal voltage to a memory unit operating under DDR (DRAM of Double Rate) mode.
2. Description of Related Art
Computer memory devices, such as SDRAM (Synchronous Dynamic Random-Access Memory), are basically driven by a clock signal in such a manner that each access action is activated either by the rising edges or the falling edges in the clock signal. Under the so-called DDR (DRAM of Double Rate) mode, the access operations can be activated both at the rising edges and the falling edges in the clock signal, thereby doubling the access speed to the memory.
Under the DDR mode of operation, however, it is required to supply a drive current (I
d
) or a sink current (Is) to the data bus of the memory so that the terminal voltage (V
TT
) on the data bus to can be pulled up or down. This requirement is conventionally provided by using a separate voltage-switching regulator IC which is externally connected to the data bus of the memory.
FIG. 1A
shows a conventional configuration for the use of an externally-connected voltage-switching regulator IC (here designated by the reference numeral
14
). In the case of
FIG. 1A
, for example, the voltage-switching regulator IC
14
is externally connected via an SSTL (Series Stub Terminated Logic) line to a memory unit
12
composed of four memory modules
12
a
,
12
b
,
12
c
,
12
d
for the purpose of supplying a terminal voltage V
TT
to the memory unit
12
during access operations. A memory controller
10
is used to control the access operations to the memory unit
12
. The SSTL line includes a pair of first resistors R
T
and a second resistor R
S
, where R
T
=56 &OHgr; (ohm) and R
S
=33 &OHgr;, for example. The terminal voltage V
TT
outputted from the voltage-switching regulator IC
14
varies with the input reference voltage V
REF
.
FIG. 1B
shows the same of
FIG. 1B
except for the use of a GTL+ (Gunning Transceiver Logic) line instead of an SSTL line to supply the terminal voltage V
TT
to the memory unit
12
. The GTL+ line differs from the SSTL line only in that it includes only the two resistors R
T
(the resistor R
S
used in the SSTL line is here removed).
One drawback to the use of the foregoing voltage-switching regulator IC
14
, however, is that, since it is a separate IC device externally connected to the memory controller
10
and the memory unit
12
, it requires an additional layout area on the motherboard for mounting, making the manufacture of the motherboard more complex in process and thus cost-ineffective to implement.
SUMMARY OF THE INVENTION
It is therefore an objective of this invention to provide a voltage-switching regulator with built-in voltage-switching module, which is implemented in a single IC chip and can be used to supply various voltages to the motherboard, including the power to the CPU and a terminal voltage to the memory unit during access operations.
It is another objective of this invention to provide a voltage-switching regulator with built-in voltage-switching module, which integrates various voltage supply units in a single IC unit, so that the layout area on the motherboard can be saved to allow the manufacture of motherboard more cost-effective.
In accordance with the foregoing and other objectives, the invention proposes a new voltage-switching regulator with built-in voltage-switching module.
The voltage-switching regulator of the invention includes: an IC chip having an input port for receiving a reference voltage and at least one output port for outputting the terminal voltage. Further, the voltage-switching regulator includes a built-in voltage-switching module integrated in the IC chip, which is capable of generating an output voltage serving as the terminal voltage in response to an input reference voltage and outputting the terminal voltage via a transmission logic line to the memory unit operating under DDR mode. The terminal voltage is pulled up when the voltage-switching module supplies a drive current and is pulled down when the voltage-switching module supplies a sink current.
The foregoing voltage-switching regulator of the invention can be implemented as a single IC unit with the built-in voltage-switching module, so that the voltage-switching regulator of the invention is capable of supplying a plurality of working voltages for various purposes, including, for example, a core voltage and a working voltage to the CPU and a terminal voltage to pull up or down the voltage state on the data bus connected via the transmission logic line to the memory unit. the transmission logic line can be either an SSTL line or a GTL+ line.
REFERENCES:
patent: 4634903 (1987-01-01), Montorfano
patent: 5808455 (1998-09-01), Schwartz et al.
Huang Jiawei
J C Patents
Riley Shawn
VIA Technologies Inc.
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