| US 7,545,171 B2 | ||
| Input/output device with fixed value during sleep mode or at a time of supplying initial voltage to system | ||
| Sung-Hoon Cho, Gyeonggi-do (Korea, Republic of); and Jae-Young Lee, Gyeonggi-do (Korea, Republic of) | ||
| Assigned to Samsung Electronics Co., Ltd., (Korea, Republic of) | ||
| Filed on Aug. 28, 2007, as Appl. No. 11/895,931. | ||
| Claims priority of application No. 10-2006-0081753 (KR), filed on Aug. 28, 2006. | ||
| Prior Publication US 2008/0048755 A1, Feb. 28, 2008 | ||
| Int. Cl. H03K 19/0175 (2006.01); H03L 5/00 (2006.01) | ||
| U.S. Cl. 326—63 [326/68; 326/80; 326/81; 327/333] | 13 Claims |
| 1. An input/output device comprising:
a level shifter configured to convert an input signal of a first voltage into an output signal of a second voltage; and
an output driver configured to operate in response to the output signal,
wherein the level shifter is configured to generate the output signal with a predetermined level when the first voltage is
interrupted,
wherein the level shifter comprises:
a floating protection circuit supplied with the second voltage and to operate in response to the input signal; and
a level shifting circuit configured to generate the output signal of the second voltage in response to an output of the floating
protection circuit, wherein the floating protection circuit is configured to prevent an input of the level shifting circuit
from being floated when the first voltage is interrupted, and wherein the floating protection circuit comprises:
a first resistor connected between a first input of the level shifting circuit and the second voltage;
an NMOS transistor connected between the first input of the level shifting circuit and a ground voltage, responsive to the
input signal; and
a second resistor connected between the ground voltage and a second input of the level shifting circuit supplied with the
input signal.
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